a new treatise of natural philosophy, free'd from the intricacies of the schools adorned with many curious experiments both medicinal and chymical : as also with several observations useful for the health of the body. midgley, robert, ?- . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing m estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) a new treatise of natural philosophy, free'd from the intricacies of the schools adorned with many curious experiments both medicinal and chymical : as also with several observations useful for the health of the body. midgley, robert, ?- . [ ], [i.e ] p. printed by r.e. for j. hindmarsh ..., london : . on verso: licensed, october , , robert midgley. attributed to midgeley by wing and nuc pre- imprints. numerous errors in pagination. imperfect: pages plus wanting. reproduction of original in the harvard university library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . science -- early works to . - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - rachel losh sampled and proofread - rachel losh text and markup reviewed and edited - pfs batch review (qc) and xml conversion a new treatise of natural philosophy , free'd from the intricacies of the schools . adorned with many curious experiments both medicinal and chymical . as also with several observations useful for the health of the body . london , printed by r. e. for j. hindmarsh , at the golden-ball over against the royal. exchange in cornhill . . licensed , october . . robert midgley . index . the first part of physick , wherein is treated of the causes and principles of nature . chap. i. of the efficient cause , and of its essence and differences . chap. ii. of the first cause . chap. iii. the perfections of the first cause . chap. iv. of second causes , and their actions . chap. v. of accidental causes . chap. vi. of sympathy , antipathy , and the effects depending thereupon . chap. vii . experiments about iron and the loadstone . chap. viii . an explication of many other effects which are commonly attributed to sympathy . chap. ix . of portative remedies commonly called amulets , of quick-silver , gold , silver , and copper . chap. x. of natural phoenomenas , which are attributed to antipathy . chap. xi . of emeticks , sudorificks , and specificks . chap. xii . of poysons , and toxicks . chap. xiii . of sublimate , arsenick , and other kinds of poysons , and their deadly effects . chap. xiv . of antidotes . chap. xv. of the true causes of our diseases . chap. xvi . of the causes of our health . chap. xvii . of formal , exemplary , and material causes . chap. xviii . of the first matter . chap. xix . of atoms , and their nature . chap. xx. the properties , magnitude , figure , weight , and motion of atoms . chap. xxi . the difficulties arising from the doctrine of atoms . chap. xxii . of a disseminate , congregate , and separate vacuum according to gassendus . chap. xxiii . of a congregate vacuum , against aristotle and cartesius . the second part of physick , wherein is treated of the coelestial world , and of those things which are above man. chap. i. of the immense spaces which are without the heavens . chap. ii. of the heavens , and their nature . chap. iii. of stars , and their substance . chap. iv. of the figures and magnitude of stars . chap. v. of the motion of the stars . chap. vi. the system of the world according to ptolomy examined . chap. vii . the system of the world according to copernicus examined . chap. viii . of the motion of the earth . chap. ix . of the sun , the true centre and heart of the world. chap. x. of the moon and its changes . chap. xi . of planets , comets , and the fixed stars . chap. xii . of meteors in the air. chap. xiii . of winds , tempests , and whirl-winds . chap. xiv . of thunder , lightning , and the thunderbolt . chap. xv. of aurum-fulminans , which imitates thunder . chap. xvi . of hail , snow , frost , &c. chap. xvii . of the rainbow , halones , and parrhelis . chap. xviii . of the air , its substance and qualities . the third part of physick ; of those things which are beneath man , ( viz. ) of the earth , and terrestrial things which are called inanimate . chap. i. of the earth and water in general . chap. ii. of terrestrial inanimate bodies in general . chap. iii. of the various qualities observed in compound bodies . chap. iv. of special qualities which arise from the composition of bodies . chap. v. of the quantity , weight , and figure of compound bodies . chap. vi. the difference betwixt natural , artificial , and compound bodies . chap. vii . of mettals and their formation . chap. viii . of gold , the king of mettals . chap. ix . of silver , copper , and other imperfect mettals . chap. x. of lead , tin , and iron . chap. xi . of quick-silver , arbor diana , or the silver tree . chap. xii . of minerals . chap. xiii . of salts . chap. xiv . of subterranean fires , aend earthquakes . chap. xv. of waters and their differences . chap. xvi . of the sea , its ebbing and flowing , and of the saltness of the sea-water . chap. xvii . of springs and rivers . the fourth part of physick : of those things which are in man , and of man himself , as he is a compound physical , and animate body . chap. i. of life in general . chap. ii. of the difference of lives . chap. iii. of the vegetative life ; common to man and plants . chap. iv. of the nature of seeds , and their propagation . chap. v. of nutrition , which is common to plants and brutes , as well as man. chap. vi. how and with what food an embryo is nourished in the womb 'till the time of its nativity . chap. vii . how a man is nourished after he is born. chap. viii . the sensitive life of man and other animals . chap. ix . of seeing , its organ and object , ( viz. ) light. chap. x. how illustrated objects are visible . chap. xi . of hearing , its organ and object . chap. xii . particular questions about hearing . chap. xiii . smelling , its organ and object . chap. xiv . of tast and its object . chap. xv. of feeling . chap. xvi . of speech , the pulse , and breathing of man. chap. xvii . of the motion of the heart . chap. xviii . of the irregular motion of the heart in animals , and in feavers . chap. xix . of the circulation of the blood. chap. xx. of the inward senses , and the inferiour appetite . chap. xxi . of sleep , want of rest , and death . chap. xxii . of the death of brutes , plants and mettals . chap. xxiii . of the rational soul and its powers . natural philosophy ; or , natural science freed from the intricacies of the schools . the desire of knowledge is natural to man , curiosity is inseparable from his spirit , neither is he ever at rest , until he hath attained to the perfect knowledge of things , that is , until he becomes a wise man. science is the knowledge of things by their causes ; therefore there is no man wise , who is ignorant of the original principles , and causes of all things occurring to him ; and since it is impossible for any man in this life to attain to a clear , distinct , and an undubitable knowledge of all things ; therefore there is no man that is absolutely wise : those who have the reputation of being wise and excellent philosophers , have obtained that preheminence , in regard they are less ignorant than others . sciences differ according to the diversity of mens conditions and professions . the noble man is conversant and wise in the art of war , the physitian in the precepts of medicine , and the advocate in matters of law and right , but all these sciences ( nay theology it self ) cannot subsist without philosophy , especially , without that part of it , which we call physick , or natural science . the first part of physick , wherein is treated of the causes and principles of nature . by nature is understood the universe , composed of heaven and earth , and all that is found between both ; this is the object of physick , this every natural philosopher ought to know ; and because this knowledge cannot be obtained , without knowing the principles and causes of things , hence it is evident , that a natural philosopher ought to use his utmost endeavour to enquire into the principles and causes of nature , and of all things which happen in this world. i shall not examine here , whether there be any difference betwixt a cause and a principle ; for every principle , after its manner , i conceive to be a cause of that thing whereof it is the principle , and no man doubts but every cause is a principle , and that all niceties concerning this matter are altogether useless . philosophers do commonly reckon all causes to be but five in number ; they give the first place to that which they call the efficient cause , which is that agent which produces the things that are in nature ; and gives them their essence and existences : in the next place , they rank the material cause , being that subject , which receives the impression of the efficient and operating cause . the third is called the formal cause , which gives a being to every thing , as the most noble and principal part of it . the fourth is called the exemplary cause , according to whose rule the efficient produces its action , when it operates by knowledge . the fifth and last is the final cause , which is the end , for whose sake the efficient produces its effect . in this first part we shall speak of all things which concern these several causes , not omitting any thing which shall be thought necessary to the knowledge of them . chap. i. of the efficient cause , and of its essence and differences . there is such a relation and connection between the cause and the effect , that we cannot have a true notion of the cause , unless at the same time we have a conception of the effect ; so in general , we say , that a cause is nothing else but that which gives being to another thing , which is the effect of it ; which way soever it happens , according to the five causes before mentioned . all philosophers do agree , that of all causes the efficient is the most noble ; because , properly speaking , this alone hath effect , though it be produced after several ways , as we shall shew hereafter . if the efficient cause acts by a power proper to it self , then it is called the principal cause ; but if onely by the force and impression of another , then it is termed the instrumental cause : so we distinguish betwixt the painter , and the pencil ; though both contribute to the production of the picture . also the universal cause , which produces many effects ( as the sun , the stars , and the elements ) is distinguished from a particular cause , which is determinate to one effect in particular : of this kind there are many sublunary causes acting in this inferior world. there is also a difference between the total cause , which produces its effect without the help of another , and that cause which cannot act alone , but only produces part of the effect . there are also necessary and free causes , the first acts necessarily and without choice ; as fire , the sun , and all created causes , except men and angels , for they act by a free will , wherein consists the essence of liberty . the efficient cause is likewise either physical , or moral ; the physical acts really and immediately , as fire consuming a house with its flame ; and he that sets fire to it for that purpose , is the next moral cause ; and he who advises it , is a moral , but a remote cause , of the consequential burning . but if the fire happens by chance , and by the imprudence of one that carries a candle in his hand , and some sparks fall into the thatch , which takes fire , whereby the house is burnt ; here this man is only an accidental cause of the burning . lastly , it is rightly distinguished between the first cause , which is author of nature ; and nature created , under which are comprehended all second causes , and such are all creatures . as to the efficient cause whereof we speak , it may be observed , that when it acts by knowledge , all the said causes , after their respective manner , do concurr to the production of one and the same effect : as , the painter drawing his picture , is the principal cause , the pencil the instrumental , the end proposed by the painter is the final cause , and the idea directing , is the exemplary cause ; the form and disposition of the parts of the piece that is painted , may be taken for the form of it , the colours , and the cloath whereupon they are laid , may be reckoned the material cause , because they are the constituent matter of the work. but if a limner in his anger throws his pencil ( as it is reported to have hapned to him who had in vain endeavoured to represent to the life a high mettled horse foaming at his mouth ) or if a limner undesignedly and by chance touches the picture , which thereby ( as it befell the former in his anger ) is made better , the representation more agreeable , the lines stronger , or more piercing , this would be only an effect of an accidental cause . there are some things to be observed in an efficient cause ( when it acts ) which are inseparable from it , such as these , the nature of the agent , the existence of the cause , the power which makes it act , the intervening act , the effect which is produced , the subject whereby , into which , and wherein it is produced ; as we shall see in what follows . chap. ii. of the first cause . the existence of the first cause , or first princple , is so evident , and so necessary , that it is like truth known by it self , and ought not to be supposed liable to any difficulty ; especially amongst christians , who are illuminated by the light of divine revelation . and since a man that submits himself to faith , hath not thereby renounced the light of reason , it will not be amiss to confirm this truth with natural reasons , lest any doubt should remain in spirits less tractable . which the better to effect , i suppose a truth so well known , that no man can deny , unless he hath a mind to be thought ridiculous and infatuated . this truth so obvious , that it ought to pass for a principle , whereupon , as a sure foundation , the existence of the first cause ought to be built , is grounded upon our own proper existence ; there is nothing so evident , nothing so certain , than that we are in the world ; this truth is confirmed by the testimony of all our senses ; whatsoever we think , whatsoever we say , and whatsoever we do , will not suffer us to imagine that our existence is an illusion : therefore it is certain , and more than evident , that we are in the world ; but that we are in it from our selves , or by our selves , or by casualty or chance , or by the necessity of being , is absolutely impossible ; so that it is necessary that we are in the world , by the means and assistance of a certain other being , who as the author , was also the free principle of that essence which we possess . this principle is necessarily either a first or second cause ; if the first , then you shall see that we are agreed , and that the true existence of the first cause , which some would deny , is rightly built upon the truth of our being , which no man can deny ; if we make the cause of our being to be a second cause , then it must be confessed , that this second cause is produced by a third , and the third by a fourth , and so in going upwards , as they do in the genealogies of ancient and noble progenies , at last we find the head of the family ; that is , the first cause , who by his great atchievements , purchased to himself the quality and title of nobility , and left those titles to his illustrious family . it is likewise true , that there is no family so illustrious or so ancient , but the genealogy of it terminates in one private person , who gave it both its name , and original , and which was the first cause of its nobility ; no certainly , unless we erect a ridiculous and an infinite genealogie ; or , like the egyptians who imagined themselves to be older than the moon , will say that its origine is as unknown as the head of nilus . in the same manner , after we have by way of ascent to our fathers , and ancestors , examined what kind of author we had of our being , whom we may call the first cause of all things which are in us , we do necessarily find a certain being which was before all things , and which is the effect of no other causes , and which is the cause of all things which are in the world , and consequentially the first , who is that god whom we adore . this demonstration doth abundantly convince any person , who hath in him the least spark of the light of reason : it is ridiculous to say , that we our selves were the cause of our being , because from thence it would follow , that we did exist before we had a being , that we gave our selves that which we were not in posession of , and that the cause and the effect was one and the same thing , which is impossible . it is no less an errour to affirm , that we are in the world by necessity ; for if we were so in the world , our existence would never have had a beginning , and we would have been immutable and independent , and infinite in every kind of perfection , which is repugnant to experience and right reason . that perswasion of epicurus and his followers is no less ridiculous , that the first authors of our existence were produced by chance , or by a fortuitous occurrence of attoms . this opinion of it self falls to the ground . let it be supposed , that the world was produced by this fortuitous occurrence of atoms , yet still the question will be , whether these atoms were created , or uncreated ? if created , they acknowledge a cause of their existence , and this cause must own another , and so ad infinitum ; which cannot be maintained ; for then the world would be eternal , and thence to this present time , there would have been an infinite number of rational souls in the world : aristotle who supposed the eternity of the world , and the immortality of the soul ; yet did deny the transmigration of souls , and would allow nothing in nature to be actually infinite ; whereby he makes himself guilty of an absurd contradiction . the same aristotle stumbles upon another contradiction , in relation to the first cause ; for if the world be eternal and without a beginning , this second cause is of no use ; for the same reason which proves the world to have a beginning , proves likewise the existence of the first cause ; on the other hand , the same reason which proves the existence of the first cause , does at the same time prove , that the world once had a beginning ; and doth demonstrate that it was not eternal . in the same manner , epicurus is guilty of an absurd contradiction , when he says , that atoms , ( which , according to his opinion , he makes to be the causes of all things ) were produced and created by another : but if he says these atoms were uncreated , and that they were eternal beings , necessary and independent ; then every atom must be some divinity , and that they are both the efficient and material cause of all things , which is impossible , because the opposition and relation , which is necessarily betwixt a principle acting , and the subject whereupon it acts , do imply a necessary distinction . chap. iii. the perfections of the first cause . they who are throughly satisfied with the existence of the first cause , must of necessity attribute to it all the perfections which are or can be in the world ; that it is not only the most perfect and most noble of causes , but also it ought to be supposed , that all the effects which it hath produced , or is yet capable of producing , are in its being in all perfections , and that every one of them is infinite , and ( as it is the first cause ) in the unity of its being ; for it is necessary it should have the perfections of those beings which it hath , or can produce ; for otherwise , it would or could communicate that which it neither hath , nor can have . the first cause would not be absolutely perfect , if it were not eternal ; for so it would have had a beginning , and might have an end , and then it could not be the first cause , in so much that it derives its existence from that which was pre-existent to it ; and by consequence , this cause which we suppose to be first , would be a second cause , limited in its being and perfections , as in its duration , and it would seem to have a dependence upon another : whereas , when we suppose it to be the first , all others must depend upon it , and be subordinate to it ; whence it follows , that these qualities of the first cause are inseparable from it , independence , eternity , infinity , and supreme authority , and that we cannot conceive any first cause , but at the same time we acknowledge the existence of god. this first cause , or to say better , this first being , which is god , must necessarily have that perfect unity which admits no multiplication either of nature or perfections . certainly , if god was not one in his being , but had several natures , the number of them ought to be infinite , and that none of these beings in particular would be infinite , because when the perfection of one cannot be the perfection of another , there will not be one to be found but will stand in need of the perfection of the other , that is , in whom there would not be requisite that perfection which the other beings do possess . i add moreover , that all these supposed beings would be opposite , independent , and all supreme , which is impossible ; or that all would be subject to one or other of them , which is ridiculous ; whence it follows , that there is but one only god , who is one in his existence , incapable of any multiplication , and who is the primary and universal cause of all things . the great number , or rather the infinity of perfections , which we apprehend to be in the first cause , is not repugnant to the supreme unity , because that does not divide the being ; and they are but one and the same thing , though we give them several names , and do consider them under several ideas , which we are forced to correct , since without that unity there would be necessarily a composition of parts , which would be the cause of the whole compound , and which would precede its existence , which cannot be the ingredient of that composition without something else intervening ; they might also be divided and separated ; so , by the dissolution of the parts , the compound would cease , which is plainly inconsistent with that idea which we have of god , who is simple in his nature , independent , and every way incorruptible . the first cause is not only one , and without its like in its essence , but also one , sole , and without a second , in that action by which the world was produced : and for this reason this action is called creation , supposing nothing but meer nothing out of which all things were made by the only power of god , without the help of any other , having either the quality of an agent or a subject . the world being produced by this first cause , remains subject to the will and pleasure of it . and in the same manner as it was produced by the sole act of this first cause , so it is preserved in the same state by the sole influence of the same cause , who as it did not want any other second cause in the creation of the universe , so neither doth it stand in need of any assistance in the conservation of it . being and nothing are so opposite to one another , that the philosophers always had it for a maxim , that out of nothing nothing could be made ; which is to be understood only in reference to second causes ; and not in respect of the first , whose power is infinite , and who can do what he pleases ; this power in the creation of the universe was not applyed according to the extensiveness of its activity , because it pleased god to terminate the being , qualities , and number of second causes , which are created . the creation was no necessary action , for the first cause did not create the world but at such a time , in such a place , and in such a manner as seemed good to it self ; so it made all those things with the highest liberty , there being no other cause either equal or superior to it self , who was able to compel , perswade , animate , or incite it to the creation of the world . the world it self could not terminate a necessary action , because it could not be eternal , for every thing that is of necessity is eternal , neither had it ever a beginning , nor can it have an end , because it is against the nature of a created being , which is limited in its qualities and duration , no less than in its natural substance . if the first cause was free in the creation of the world , thence it follows , that all things were made by direction of reason and understanding , and by consequence , according to a certain idea and rule : but because the first cause operates after an independent manner , it could not have the type of its production any where else but from it self , neither could it act by a rule distinct from its own being ; so god is not only the efficient , but the exemplary cause of all things . for the same reason it may be said , that the first cause , which is god , is the final cause of all things , for when he , as an intelligent and free cause , produced the world , he did propose to himself an end answerable to his dignity , that is , himself and his own proper glory ; so that the first cause is necessarily the ultimate end of all its effects . chap. iv. of second causes , and their actions . all creatures are called second causes , because they depend upon the first , neither do they operate but by the command and impression of the first ; this first or universal cause does act uuniversally with particular causes , but after a manner agreeing with the nature of every particular thing , and according to the power which was given it when it was created ; which does not alter the nature of the causes , nor the necessity or liberty of their actions . this power of acting , which is granted to second causes , is not a quality different from their nature and being : so the power which the atoms have of moving themselves , doth not differ from the atoms themselves ; the power of burning or heating doth not differ from the fire to which it is inherent , unless it be in the manner of our conceiving things , and of speaking of them according to our conceptions . so it is of an action which terminates from the cause to the effect , and which is nothing else than a certain relation , or an actual subordination , which is found betwixt the cause and the effect . this action is never without motion , or to say better , action and motion is one and the same thing , thence it is that a thing rests when it is without action , and then it begins to move it self when it begins action ; so according to three ways of acting , there are found in the nature of things three kinds of motion . the first is made without sense or reason , which we may see in stones , mettals , plants , and the heavens . the second kind of motion is made by sense and knowledge , as are seen in all living creatures : the third kind joins reason to sense , as we observe in man acting by phancy , who proposes an end to himself , distinguishes between good and evil , and hath the liberty of prosecuting the several objects presented to his view either with love or hatred . as an action is not indeed distinct from the cause acting , nor from the effect which it doth produce , so motion doth not differ from the thing moved , or from the thing which moves it , but both of them is , accordingly as they change their condition , or cease to rest , which from the creation was never done , without a certain local motion of the whole , or some part thereof ; so , the notion of rest is opposite to the notion of mutation and action , as well as motion . chap. v. of accidental causes . there are many causes which are called accidental causes , for , properly speaking , they are not true causes ; which sort of causes happens four manner of ways ; first , a musitian draws a picture , not as he is a musitian , but as a painter ; so that the art of painting is the true cause of this work : and as the art of singing contributes nothing here , since it falls out by chance , that the art of singing , and the art of painting meet together in this man , and since the art of singing is no way requisite for the making of the picture ; in this respect , we may say , that the musitian is only an accidental cause of the picture which he hath drawn . secondly , a remote or indirect cause is called an accidental cause ; as when we say , that the sun is the cause of darkness , because darkness is occasioned by the absence of the sun ; mirth is the cause of sadness , and peace arises from war : as a man endeavouring to save his friend , whose life is in danger , and thereby unwillingly exposing him to a certain death , is the indirect or accidental cause of his death : as he , who perswades his friend to cross the seas , whereby he is cast away . thirdly , an opposite cause ( which produces an effect quite contrary to that which it ought to produce ) is an accidental cause , as it was with the subjects of such tyrants as persecuted the church , and thereby procured glory to martyrs ; and as those , who were the death of our lord jesus christ , obtained us life , destroyed the synagogue , built the church ; they fulfilled the prophecies , and laid the foundation of the gospel . in the fourth and last place , that is an accidental cause which produces a particular effect not foreseen , and according to the course of nature unavoidable ; if it hath respect to an intelligent cause , and the effect be agreeable to wish , the heathens did point at this by the name of fortune , and according to their way of speaking , we say such a thing is the effect of fortune ; as when a man is digging up the foundation of a house , and by chance finds a treasure ; but if the effect be otherwise than prosperous , then it is misfortune , or the chance of fortune : as when a tile falls from the top of a house upon a mans head that is passing by , and kills him ; here the tile is the physical and accidental cause of this mans death , which was inevitable according to the course of second causes , having either their free or necessary motions : these accidental causes gave the heathens occasion to frame to themselves a blind goddess , which they called fortune , to whom they did attribute an unconstant , an uncertain , and a various disposition of good and evil ; to this man 's good , to that man's prejudice : of all errors this is not the least , neither was it entertained by any , but the ignorant and the meaner sort of people the wiser sort in that age did aim at a cause of all the effects which happen in the world , that was less feigned , and more solid ; this they would have to be fate , and that what without any reason was ordained by this universal and chief cause was inevitable ; so when any great misfortune happened , as the loss of a battel , the defeat of an army , the change of state , the subversion of a common wealth , or the sudden death of some illustrious person ; all this was ascribed to fate ; and they did commonly say , sic erat in fatis , this was the inevitable will of fate ; so the fates would have it : and when any person undertook any great enterprise , as it was said of aeneas , being in search of the golden fleece , ( if the fates call thee ) that is , if the fates favour thee ; thou shalt attain thy end . the great wits of our age are almost of the same opinion , concerning all the various successes of prosperity and adversity , and all things which come to pass in this life ; as if humane prudence had been of no use , and divine providence without any care had been idle . but that we may speak like a christian philosopher , supposing the existence of the first cause , and having demonstrated that it hath all the perfections of the chief cause , since wisdom and power are the two inseparable perfections of the supream being , and indeed so necessary for the conservation and government of humane affairs ; we ought to conclude , that nothing happens in this world , which is not decreed , foreseen , directed , and perfected , by the wisdom ; and strong hand of some supream cause , which so exactly directs all things , that they come to pass , according to the end that was proposed in the production of them , and indeed all those things , by means unknown to humane wisdom ; yet notwithstanding , in respect of god , who is the first cause , they are certain and infallible , who established the infallibility of effects , in such manner , that causes in their motion , should be neither forced , nor too violent : there is nothing but what god soresees , nothing but what is absolutely inevitable , and free causes act always freely , in actions which ought to be free . chap. vi. of sympathy , and antipathy , and the effects depending upon them . the wonderful effects which we see in nature , whose true and natural causes are not easily found out , obliges philosophers to have recourse to occult causes , and to attribute all these effects to natural sympathy and antipathy , which happens amongst the several bodies whereof the world is compounded ; but if you press these philosophers to tell you , and to explain wherein this sympathy and antipathy doth consist , they will give you no other reason , but onely tell you , they are done by certain occult and unknown causes , to which they ascribe all those effects , whose true causes they do not at all know . but they would do much better , plainly to confess their ignorance and say they know nothing of the matter . that we may the better understand what may be said upon a subject so nice and delicate , and give a reason ▪ of those wonderful effects which are attributed to simpathy and antipathy , without the help of occult causes ; in the first place , i suppose that the difficulty which occurs in explaining an effect of this nature , doth arise from this ; that the mind is not able to know the truth of things , but by the senses , which are the gates through which the objects enter , and form their ideas in our understanding ; but because there are abundance of things which escape our senses , it is no wonder , that it is so hard to give a reason of things which are so remote from the reach of our senses ; as for example , iron moves it self , and that by way of local motion , and joins it self to the load-stone ; we do not see that which draws the iron to it , though we see it attracted , but we know not by what ways or means it is done ; but if we explicate this , and such like effects , by saying they are wrought by sympathy , obscure and occult causes , we deceive our selves ; for that is only a shelter , and the true way of hiding our ignorance , which we are loath to discover , for there is no man in nature so blockish , but after this manner can resolve all the phoenomena in the universe . if it be asked why the needle turns always to the north pole ? is it enough to say that there is a sympathy betwixt this needle which is touched with the load-stone and the pole , and that the cause of this sympathy is obscure , unsearchable , and past finding out : but if this be the way of philosophising , i refer it to those who are competent judges of the matter . therefore that we may give a more ingenuous and solid reason , in the second place , i suppose that there are no bodies but that continually emit certain subtile particles and imperceptible corpuscles which are dispersed through the air , and are at sometimes carried at a great distance , unless they justle with other bodies in their way . by the help of this principle , we find the reason why a dog follows the foot-steps of a hare , or from a heap of a thousand stones , he readily knows that stone which his master threw , and picks it out , and by his command brings it to him . from this dispersion of corpuscles , we find the reason how the contagion of the plague , either from the person infected , or from the wind blowing from that region , is carried a great way of , as also the reason that the smell of rosemary is perceivable at a hundred miles distance , as sir kenelme digby observes ; and likewise the wonderful cure of persons wounds , which are far distant , by the means of the sympathetick powder ; so likewise of the fermentation of canary wine , brought into england , which ferment here at the time of their vintage , when the vines in spain flourish and are in the budd , and such like . i suppose farther , that all these small corpuscles do differ as to their figure and magnitude , and that they are not equally received by this or that body ; so one man is infected with the plague , in the same place where are many others untouched . for the same reason , the beams of the sun do melt wax , and not lead , unless they are collected and united by the help of a burning-glass , or the like ; and the heat of fire melts mettals after a very different manner . lastly , i suppose that it is somewhat difficult to give a solid and sufficient reason of all the experiments which daily occur in the nature of things . truly we are surprised with no small admiration , when we see iron move at the presence of the load-stone , and to approach it , as if it were endued with a kind of sense and knowledge ; the palm-tree of the male kind is barren , unless the female be planted near it , but if they be separated by a river , they both lean to one another , as if they would embrace each other . if you strike the string of a lute in one corner of a room , it shall cause the string of another lute , tuned to the same heighth , and placed in an opposite corner , to give a sound ; but not another . the cock always sings and claps his wings in the same moment that the sun ascends above the horizon ; all effects which we see from sympathy afford us matter of admiration , and compel us to acknowledge that sympathy to be the daughter of ignorance . the same thing may be said of effects which are attributed to antipathy , no less amazing , and no less difficult to be explained ; who can without much difficulty explain the natural aversion that is between the colewort , and vine , so that if it be planted near a vine , the vine will give back , and so will the golewort on the other side ? who can give a reason that sheep should shun a wolf though unseen ? or that a drum made of sheeps-skin , should not sound where there is in place another drum made of a wolfs-skin ? or that when we are seen by a wolf , before we see him , we are hoarse . who can give a reason that the basilisk should kill by sight ? and other effects of this kind , which are frequently observed . but because that phoenomena of the load-stone before mentioned , seems to me to be a matter most worthy of consideration , i shall treat of this subject in a particular chapter by it self . chap. vii . experiments concerning iron , and the load-stone . the load-stone is a stone sound in iron mines , not much different from the nature of iron , wherefore the particles which proceed from the load-stone , have a kind of agreeableness with the pores of iron , so these small corpuscles going out of the load-stone , and meeting with the iron in the way , do rush into the pores of it by troops ; but because all cannot enter at once , a great many remain without , and these are as strongly beaten back by the particles of the iron which they meet with , as if they were of the number of those corpuscles , which being at liberty , do return of their own accord , which at length do send these by a reflective motion to the load stone whence they first came : hence it is that iron is drawn towards the load-stone , principally by the agitation of those minute magnetick corpuscles moved in the concavities of the iron , and being shaken together by the sundry motion of those corpuscles which are twisted one within another , those corpuscles which do return , by reflection are complicated and annexed to those which are in the pores of the iron , or else have passed them through , and cannot be returned or moved towards the load-stone , unless they draw along with them those corpuscles to which they are annexed , and which cannot follow , unless by their motion the iron be carried with them ; so the iron follows , and is moved towards the load-stone , except the iron be bigger than the load-stone , for then the corpuscles which proceed from the load-stone are not so many , nor by consequence so powerful , as to draw the iron , or the impression which they make upon the iron is not strong enough to cause a renitency to pass that side by which they ought to be beaten back . this is the reason that the load-stone draws no other body but iron , because other bodies do not return the atoms , neither are their pores well fitted for those magnetick corpuscles . by the same reason it does appear that the load-stone ought not to approach to the iron , but the iron to the load-stone : it may be said , that hard and solid bodies , such as iron is , cannot emit such a great number of corpuscles as other bodies , which like the load-stone , are less solid , and more porous . also there may be a reason given why the load-stone being rubbed with garlick , or oyle , doth not so easily draw iron to it , especially if you also rub them with it ; because these strange corpuscles by their oyliness do hinder the emission of the corpuscles out of the load-stone , and also their entrance into the pores of the iron , and do break their elastick force . we may observe many other effects of the load-stone . as for example , that iron put upon a table , is moved by the vertue of this stone which is placed under the table , for it is certain that the spirit , or corpuscles of the load-stone , which moves the iron , penetrates through the vacuity or pores of the table , as if by small and invisible threads it had been tyed to the load-stone ; it is the same thing if the table be of marble , or glass , provided it be not greasie , nor too thick ; which proves the porosity of bodies . we see another effect of this stone in a needle , which being touched by it , always turns towards the pole , we suppose for this reason , because there are whole mountains of load-stones found under the poles , dispersing their spirits through the universal world. spirits which are entangled with those , which do adhere to the magnetick needle , whose force is lessened , as the spirits of it are dissipated ; especially if the compass be set in a place where there are pieces of iron , to which the spirits stick , and leave the needle , which had taken no greater quantity of them than what was requisite according to its capacity . that which is most wonderful in this stone is , that we see it draws iron on one side , and rejects it on the other , so that it appears in every load-stone that there are two poles of the world ; the north pole attracts iron , the south pole repels it ; because the spirit of the north pole enters in at the pores of the iron , but the southern cannot , for it strikes against the iron , and drives back too much its elastick particles . this explication presupposes the being of spirits , and atoms , and their figures and motions ; and as also , small occult vacuities which are dispersed through all bodies , as we shall shew hereafter . chap. viii . an explication of many other effects , which we endeavour to attribute to sympathy . i do not design in this place to shew all the effects which do proceed from sympathy , and to give the reason of every one of them in particular ; i conceive such a labour , besides that it is very difficult , is moreover useless , for an explication of one , will serve to explain the rest ; therefore instead of all , it will be sufficient to explain some few of them . that which first presents it self to our consideration , is the sympathetick powder , the sympathetick wood , and the sympathetick ointment , an amulet , and the medalls , which are of the same nature , which they call talisman . sir kenelm digby reports , that the sympathetick powder will cure a wound , when the person wounded is distant a hundred , nay two hundred miles , so that the cloath be dressed , to which the matter or blood sticks which proceeded from the wound ; but principally there must be care taken , that the wound be kept clean , and that the cloath be kept in a temperate place , for if it be thrown into a place which is too warm , it will cause an inflammation in the wound ; no solid reason can be given of this phaenomenon , so wonderful in it self , but that it is by a continual entercourse of the spirits proceeding from the bodies , which by continual motion , are coming and going , and keeping a tye or bond betwixt the bodies , and though our senses are too gross to perceive them , it doth not therefore follow , that there are not such things ; as it appears by the example of the spider descending , or ascending , and drawing after him an invisible thread which proceeds from his body ; so that he being in one end of the chamber , remains firm and fixed to the other end , by the same thread , by which he bears himself up , and is moved from one part to the other : i confess it is hard to conceive that there should be a thread of communication betwixt the wound , and the blood which issued from it ; but that is neither impossible , nor incomprehensible , though the phenomenon is not plainly infallible ; because this thread being broke , or interrupted , the wound cannot be cured , unless we take again fresh blood , and excite it by the means of this powder , whose spirits do drive those which are in the blood , and mixing themselves by the strength of the powder , do carry and communicate its vertue to the wound , and that at a considerable distance , but not indifferently , not at the distance of a hundred miles , as it is conmonly believed ; it is certain if that were done by sympathy , the effect would be the same , at any distance , neither would it ever deceive us . i cannot produce any more sensible or just reason to explain the vertues and effects of the sympathetick powder , which depend much upon the due preparation of it ; they do not extend themselves so far , nor are they so infallible , as some would have , for the reasons by us alledged . the same thing may be said of the sympathetick wood , which stops blood , if a little of the blood which runs out of the would be put upon this wood , where so soon as that blood is dryed the flux of the other blood is stanched , and this they say is done by sympathy ; but the true reason proceeds from the invisible adherence whereby both these bloods are so subtilly connected together by the astringent vertue of this wood , and by this thread of friendship , composed out of atoms variously twisted together , communicates it to the blood which flows in great quantity , whereupon this flux , if it be not too vehement , is stopped . if this effect did arise from sympathy it would never deceive us , because nothing can oppose sympathy ; but it is not infallible , as experience shews us . of all the effects which hold us in suspence , that which we call the divining-rod is not the least , for it is very strange to see a rod which is held fast in the hand visibly to incline , and bend it self towards that place where there is any water or mettal , and more or less as the water or mettal is nearer to the superficies of the earth , or is more remote from it , and more deep in the ground ; and that which is most stupendious , is that this rod which does it , shews no motion , but in the hands of those who have obtained a particular vertue to this purpose , which distinguishes them from others , though it cannot be said who gave them this power , nor why this rod hath this motion in the hands of one man , and not in anothers . concerning this subject , the cause of this motion is to be considered , which cannot be attributed to sympathy , for sympathy is a necessary cause , and then this motion would be always , and in the hands of every body , which yet we see is not done . therefore the most natural cause is to be enquired into , which i deduce from these mineral or aquatick spirits , issuing from those places wherein the mettals or waters are ; which meeting with the rod , whose pores are fitted for them to lay hold on , attracts it by a perpendicular motion , which is natural to them , and bends it as it were with a silken thread , or a golden chain . the difficulty is about the hand which holds the rod , for every hand is not qualified for this purpose ; nor is every tree fit for it , unless it be hazel , or some other of the same quality with it : as to the hand , it is certain that the hands as well as the men do differ , and that the spirits proceeding from them are different , and so it ought not to be looked upon as such a wonder , that there should be spirits which retain the rod , and hinders this motion , and that they should proceed from the hand of one , and not from the hand of another ; and that every sort of wood is not fitted to receive the hold of all atoms . of portative remedies , which are called amulets , i say nothing , but what experience taught me concerning them ; and of the manner how quick-silver sticks to gold , and silver to copper , which forces me to write a particular chapter concerning them . chap. ix . experiments concerning portative remedies , of quick-silver , gold , silver , and copper . there are certain remedies by physitians called amulets , which give ease to humane bodies in many distempers , as long as the person carries them about him , as experience teaches us of a spider shut up in a nut-shell , and hung about the neck , is good to cure all diseases of the lungs ; the true nephritick stone being carried about one , cures the stone ; a little bone of the thigh heals the sciatica ; quick-silver , or a toad hung about the neck , is a preservative against the plague ; the tooth of a dead man carried about you shall cure you of the tooth-ach ; oak-moss gathered at a certain time , and an elkes hoof cure the epilepsie : there are such as preserve children from having the small-pox , and others , which being tied to the wrist cure the tertian , and semitertian . so there are many others , whose effects are ascribed to occult causes , and to the sympathy and antipathy of things . i do not question the truth of these experiments , because i am certain as to the greatest part of them , having tryed them . without doubt there are many others which i do not know of , and which nevertheless others might have seen , but this i know , that the aforementioned effect is not infallible , and when it happens , it is done by the emission of certain spirits or atoms proceeding from those remedies , and penetrating the pores of mans body , and giving strength to the animal spirits to resist internal poysons , or resisting the external poysons , and fixing and hindring them from hurting those who carry the amulets ; i shall say nothing of medals ; which are called talisman , importing good luck to those by whom they are carried about them , nor of white magnets , which procure the kindness of all people , and the favour of a mistriss : i give little credit to such things , neither can i easily believe all things which are said of them ; and if stars ought to have place here , rather than demons , all is done by the means of atoms . now i come to that which i am better acquainted with , and of which i can speak with more certainty , i mean of experiments concerning quick-silver and gold ; it is certain that if any man hath quick-silver in his body , or any where about him , that the gold-ring which he hath upon his finger , or which he holds in his mouth will turn white , because the quick-silver sticks to the gold ; and if this gold-ring be thrown into the fire , the quick-silver flyes and evaporates ; and if the same ring be again put upon the finger , or held in the mouth , it will still grow white every time , as long as any quick-silver remains in the body . this phoenomenon is commonly ascribed to a sympathy which is betwixt quick-silver and gold ; as if the quick-silver should hastily go to the gold and embrace it , or that the gold did draw the quick-silver to it ; but gold enclosed in smooth glass does not turn white , no more doth it then when quick-silver is enclosed hermetically in a glass , there is no sympathy to call it forth thence , no more than out of a box or bladder wherein it is kept : we ought not therefore to say that it was the sympathy of these two mettals which was the only cause by which the one adheres to the other , for though we should grant that there is a sympathy , that is , an agreeableness , proportion , and likeness between these two substances , not in their imaginary qualities , but in the figure of their atoms ; nevertheless it must be confessed that the attraction of quick-silver to gold , is by an emission of their spirits and corpuscles , near after the same manner as we observed of the load-stone and iron . there is no less a connexion betwixt silver which the chymists call the moon , and copper , which they call venus , than there is betwixt mercury , that is in their dialect , quicksilver , and the sun , that is gold. if one ounce of silver be disolved in three ounces of aquafortis , made of nitre and vitriol , the silver is reduced to water , neither is it ever after seen , and if we would recover the silver after such a dissolution , you must take leaves of copper , and put them into an earthen vessel , and pour upon them one pint of common water , then to this water put the liquor in which the silver was dissolved , and it will turn it as white as milk , and in the space of two or three hours , the silver will leave the aqua-fortis , and joyn it self to the copper in the form of curd or white moss ; when the water is clear , throw it all out the silver sticking to the copper is dryed and reduced to a mealy powder , and this is called calx lunae , or silver calcined . as to this , we must take notice , that if in stead of copper , you put in leaves or pieces of gold , silver , lead or tin , the experiment will not answer expectation ; neither will silver stick to them as well as to gold , whence we must necessarily conclude , that there is a certain sympathy or peculiar connexion between silver and copper , as there is betwixt gold and quick-silver , so that we grant , that if the transmutation of mettals be not impossible , no mettal can be sooner changed into another , than copper into silver , and mercury into gold : the difficulty is in knowing the true cause of a connexion or affinity which is so remarkable . it is commonly said to be done by that sympathy or agreeableness which is between these two mettals . but in saying that , we say nothing , for we must enquire farther into the cause and foundation of this sympathy , so that we are forced to search for another cause of this effect , and to say that silver is not joined to copper , but by the means of a certain local motion of the particles of the silver , which are dispersed in this great quantity of water , and are congregated to joyn and unite themselves to the copper ; there is no other cause of this local motion , besides the spirits and scent of the copper which are dispersed thorow the water , and there meeting with particles of the silver which are wandring , separated , and dispersed , are fixed to them by reason of the conformity of their pores ; when the corpuscles of the silver are loosed , and set at liberty in the water , they leave it and descend , being forced downwards by the concurring particles of the water , and leaving no vacuity , wherein the particles of the silver may be contained , they find the atoms of the copper , emitting themselves like the odors of aromatique bodies , and mutually entangle one another like littlè hooks , they go directly towards the copper , and falls upon it as it lies in the bottom of the vessel ; this explication doth imply the doctrine of atoms and their figures , weight , and motions , as it shall appear in following chapters , after we have discoursed of antipathy . chap. x. of natural phaenomena which are attributed to antipathy . there are observed to be many effects , for which no reason can be given without the help of this feigned antipathy . i 'le instance to you some few , which i shall endeavour to explain . in the first place occurs the sight of the basilisk , who kills all whom he sees , which they say is by antipathy , which is betwixt it and other animals . but it may be said rather that it is done by the emission of certain venomous spirits , which penetrate the eyes of those which were seen by the basilisk . the nature of this poison cannot be explained , unless we know before what is said of poisons else-where . i thought that the deadly effects proceeding , which we attribute to antipathy , did deserve a particular tract by it self , because poison kills only by a contrariety betwixt us and it , so there is nothing more to be said of these matters , only that we are to discover and declare the principle of this contrariety : of the basilisk of whom we speak , i shall only say that the spirits issuing out of his enraged eyes , do kill those animals which they meet with , because the spirits do penetrate them by their subtilty , and sharp figure , like needles , which pierces the heart , as the poison of vipers , and such like , not so accute , nor so deadly , nor so ready in their effects , as that of the basilisk . in reference to this matter there are many things which occur , that are worth consideration . in the first place , it is certain that the basilisk is not ingendred but in moist , deep , and dark places , as in the bottom of wells , where there is nothing but muddy , thick , stinking water , as histories do relate to us , that some have died only by looking into those wells , or in going down into them , in order to cleanse them . in the second place , we do observe , that if you take a glass and hold it against the basilisk's eyes , those spirits which issue from his eyes , reflecting upon the glass , are sent back from whence they came , and do kill the basilisk : it cannot be said that the basilisk doth hate himself ; but it must be said that the venomous spirits , reflecting from the glass , do conceive a more violent motion , and do forcibly enter the eyes of the basilisk , and do drive back the other spirits which are issuing out of , or are extant in , his eyes , so that they penetrate his brain and heart , and thence occasion his death . in the same manner , as vapours do often arise with so great violence from the hypocondria , the mesentery , and the stomach , into the head , that they cause an apoplexy , epilepsie , diziness , or lethargy , and sometimes they are carried with such subtilty and violence into the heart , and presently penetrate it ; whereby men dye suddenly . it is also observed , that several men , and other animals were killed by a basilisk , from the corner of a deep and dark dungeon where he was ingendered , and nourished up to the bigness of a toad , it was contrived that one should enter into the dungeon to kill him ; care being taken , that he who was to enter for that purpose , should be covered with a glass before his eyes , by whose interposition the basilisk might be seen , though he could not see the person approaching towards him . by this means , he who entered saw the basilisk , and killed him , without receiving any hurt to himself ; which without doubt did proceed from this , that the poisonous spirits issuing from the eyes of the basilisk , could not pass freely thorough the glass , but were fixed in the substance of it , so that they could not hurt the person who was so covered . another effect which is ascribed to antipathy , and must be spoken of in this place ; is that which we meet with amongst some vegetables , as betwixt the colewort and the vine , betwixt whom as we observed before , there is not the least agreeableness , and that if they be planted near one another , they do insensibly give back , and lean sidewards , as if they really hated one another , this effect cannot be ascribed to any thing but to the emission of the corpuscles and material spirits of both of them , which do rush upon one another , and mutually repell by the irregularity of their figures . this truth is apparent in the juice of coleworts , which if taken by a man when he is drunk , he presently comes to himself , and is sober ; because the corpuscles of the juice of coleworts do blunt the corpuscles of the juice of wine ; in the same manner , we find by experience that spirit of opium , or laudanum , cures the chollick , head-achs , and all other kind of pains ; nay , it eases the tooth-ache , and blunts the sharpness of choller ; it cures the phrenzy , and procures sleep ; so there 's need of the greatest care in using the narcotick medicines , because it often falls out that the vital spirits are so stupified by them , that they are deprived of their motion , which causes a deadly sleep . but that we may return to our so much believed antipathy , which is betwixt the colewort and the vine , i observe , that it hath not the above mentioned effect ; and that neither the vine nor the colewort do lean sidewards , if there be cloth or paper set betwixt them ; and though the same antipathy remains , it doth so manifest it self , because the corpuscles flowing from both sides are stopped in their way , neither do they pass through the cloath or paper ; so the truth of that assigned by us , and the weakness of that reason which is grounded upon antipathy , clearly appears without any further scrutiny . there is a third effect which is ascribed to antipathy , and it is observed in the use of medicines , as well internal as external ; some whereof are catharticks , some sudorificks , and others specificks : the external of which we speak , are those which we carry about us , which by their antipathy , drive away the malign air , and preserves from the plague , and other contagions ; as prepared quick-silver , and a toad dryed and shut up in a box ; this phenomenon is not in the least to be ascribed to antipathy , but to the pestiferous spirits or corpuscles , which approaching towards us , do find subjects apt for their reception , and are fixed in them , but they do not approach us , at least in such a quantity as is able to hurt us ; which most evidently appears , in that prepared quick-silver , or the toad , being once replenished with these contagious atoms , become useless , and they ought to be changed and renewed ; and i know by experience , that quick-silver prepared white , and shining like an adamant , or polished silver , and being carried about a person who is frequent with sick people , in time becomes black , so that afterwards it is useless to him that carries it about him , because there are no small vacuities left to retain the airy poisons , unless he renews it by another preparation , whereby it may be made as white , transparent , and as useful as it was before . moreover quick-silver turns black , more or less , sooner or slower , according to the proportion of the lesser or greater malignity which is in the air where he lives , because these antidotes can never hurt ; nay , if rightly prepared , they do not only withstand the contagious air , when they hinder its nearer approach towards us ; but as it is evidenced by experience , they do suppress inward vapours ascending up into the head , which occasion many of our common distempers : it were to be wished that sacred persons , and princes , whose lives are so dear unto us , ( to the end they might preserve their health , and not be any way subject to any danger of this kind , ) would carry these antidotes about them , and that those who have free access to those sacred persons would advise them to it ; and likewise demonstrate the use and vertue of them . i proceed to purgative remedies , this carries off choller , that phlegm , others melancholly , and others do purge the blood and all the humours . it is hard very often to give a reason why rubarb and the leaves of sena do purge melancholly ; jallap and diagridium purge out phlegm and waterish humours . whether this be done by sympathy , which attracts the humours from the several parts , or by antipathy which expels and exterminates ; but it may be said that it is done neither way , and that a matter of so small a moment , did not deserve that strife betwixt the followers of galen , and paracelsus , for their axiomes concerning contraries against contraries , and like to like , contribute nothing to the explanation of these effects ; for i take it to be a certain and constant truth , that every purgative medicine doth comprehend in it certain spirits or corpuscles which are venomous , that is acute , sharpned , pungent and biting , so that nature being stirred up by them , and thereby the internal parts and membranes being touched and agitated , the animal spirits get together by troops , in order to assist the part affected , and they draw along with them the foreign humours , which are less fixed ; and then nature by the help of these spirits doth discharge it self , and expel them by their proper ways : but to say that rubarb makes choice of exterminating choller , or the leaves of sena of carrying off melancholly , is ridiculous . it is true , that after a purgation with rubarb , the waters proceeding from the body are yellow , and after the use of sena , or cassia , they are black ; yet it does not follow from thence , that this purges choller , and that melancholly ; they are only the superfluous humours which are discharged , neither doth the body afford any thing , besides that which it hath ; whether sena or rubarb be taken , the colour of what is purged , proceeds from a tincture of these medicines . chap. xi . of emeticks , sudorificks , and specificks . of all medicinal remedies those seem most admirable to me , which are called emeticks or vomitives , which have in them a great deal of poison , and likewise abound with arsenick spirits ; amongst minerals , antimony and arsenick are of this kind ; so are the herb asarum , and other herbs , amongst vegetables . it is evident that all these simples and minerals , consisting for the most part of many sharp and corrosive corpuscles , do not purge the body , but by pricking and irritating of the membranes , and that some times with such vehemency , that the belly and other contiguous parts being ulcerated thereby , there happens a breach of the internal continuity , &c. which occasions the death of the party who is thus affected . it is apparent , that it ought to be acknowledged for a certain truth , that these sort of medicines ought to be used but very seldome , but if necessity requires the use of them , none but the gentlest are to be applyed ; it being taken for a constant truth , that those persons who use these remedies too-often , do never enjoy a perfect health , and that their lives are always short and crazy . let us consider an emetick , and especially antimony , which being well prepared , performes wonders : i mean , by a good preparation of it , that it be freed from a great quantity of its pernicious and poisnous corpuscles . as to this , it ought to be prepared by judicious artists , for if it be so ordered , that the antimony purges neither upwards nor downwards , and that it retains only a sudorisick vertue ; being thus qualified , it is very proper , and very useful , to purifie the blood , to increase the animal spirits , the natural heat , and radical moisture , for reasons which i shall shew hereafter . but if these venomous , arsenick , and corrosive corpuscles be not separated from the antimony , it may prove to have very ill effects , in that it imposes violence upon nature : it is not to be administred but by a prudent and most expert hand ; though the substance of it be not taken , but only the wine wherein it is infused . but your crude and diaphoretick antimony which the late . mr. de l'orme called his milk of pearls , is very comfortable to nature , and may be safely used with very good success ; but to find the cause of that effect , the learned are very much puzled . i shall endeavour , according to my principles , to shew the reason of this effect : it is made in this manner , take crude antimony , and thereof make a starry regulus , which is all as one if it be not starry ; of this melted regulus you are to make a cup , put wine into it in the evening , pour out the wine the next morning , and you will find that it hath lost nothing either of its tast or colour ; yet notwithstanding , it is very purgative . that which is to be admired at , is , that this may be done continually every day , without any remarkable diminution of the cup , or loss of its vertues . if the wine loses or receives nothing , as it seems it does not , how then can it be purgative , or emetick , and if the cup communicates to it either its substance or vertue , how then is it possible , that either one or the other is not in the least diminished ? according to our principles i return this answer ; that the wine every time it is put into the cup , doth take from thence certain corpuscles , or invisible spirits , wherewith it is impregnated , and that little is sufficient to give the wine a purgative vertue , and to stir the membranes of the ventricle , and the inward parts , in order to evacuate the peccant humours ; which is evident from this , that the wine according to the proportion of time it hath stood in the cup , is either more or less purgative , though the cup suffers no sensible diminution in its substance , yet not withstanding , it is certain that it will suffer some small diminution in the course of some years ; which it were worth while to observe . i have spoken above of a regulus starry , and not starry , that i may let the reader see somewhat that is strange in the confection of regulus , when it is well prepared with mars , that is , with iron ; there is to be seen a great star upon the upper side of it , which hath five rays , like the rowel of a spur : i confess that in this strange phoenomenon there is something that is wonderful , and which is beyond the reach of humane understanding , especially if we observe , that this star is more bright , and its rays better formed , if the regulus be prepared either tuesday or friday , especially if the sky be clear and serene ; and if it be made between seven or eight of the clock in the morning , or two or three of the clock in the afternoon : and that i may build one wonderful thing upon another , it is certain , that if in the preparation of regulus , tin be added with iron , there will be seen two stars upon the regulus , with their distinct rays dispersed into one another , and if the regulus be driven to the last degree of perfection , the star disappears , and there is seen in the room of it a little thin net , like a fishers net : i am so far from delivering any thing upon the credit of others , that i set down nothing but what i my self have done and seen . having let you see the manner how it is done ; there remains only that i should give such a reason of it , as may in some measure satisfie the readers understanding ; i do not brag that i am able to do it , for there are few men which are rational ; i mean who are contented with reason , nevertheless you shall have my thoughts of the matter . no man doubts but that iron represents the planet mars , copper venus , gold the sun , silver the moon , and tin jupiter ; if the qualities of these mettals be compared with those of the planets , as the heavens do incessantly influence the earth , and the earth sends back its corpuscles to the heavens in the form of vapours , in the same manner do the heavens return them to the earth in rain , and dew ; and though there is a general commerce between the heavens and the earth , yet no man will deny , but that there is a certain invisible and particular commerce betwixt them ; and that we may not speak of things so general , there is a more special commerce betwixt the sun and gold , and betwixt the moon and silver , mars and iron , venus and copper ; so every planet hath a special influence upon its mettal , and the nature of it , by the means of the invisible atoms and corpuscles which proceed from the body of the planet , which plainly appears by all the former instances , and amongst the rest , for that the day and hour of the planet , contributes to the formation and perfecting of either the single or double star , as we have observed about the starry regulus . these things being supposed , i conceive that while antimony is melting with iron , there is much vapour and smoak arising , and this is most certain , that the smoak evaporates in such plenty , that it is troublesome to the artist , who is obliged to stand at some distance , if he will have a care of himself : these vapours and smoak do ascend up , which being met with by the spirit and corpuscles of their planet , do mingle with them , and descend upon the mettal and penetrate it , because , being melted , it is open . therefore these emancipated spirits do return more pure than they were , and do so well intermix themselves with the open mettal when it is melted , and that they draw others to stick unto them , whence the spirit of the planets , though invisible , descending from the body of the planets , not being able to enter into the regulus when it is removed from the fire , and begins to coole , are forced to stick upon the upper and superficial part of the mettal , and there form the figure of the planet or planets from whence they did proceed , and when copper is put to it , there appears a double star , and this star is the more elevated , when the spirits of the planets are more copious , which they are at the day and hour where in the planet rules . all these things agree with experience , for the single or double star doth not appear till the mettal begins to cool , which requires about the space of an hour ; and this star is formed by degrees , which is strange , nay , to be wondred at ; whence it appears , that there is an agreeableness between mars and iron , and betwixt venus and copper , and that there is an influence of their planets upon these two mettlas by the intervention of their corpuscles . as for the net ( which we spoke of ) it shews the conjunction of the planets of both mettals , having the sun in the middle , and i am not able to give any other reason for it ; unless that when the mettals , which are melted with the antimony , begin to grow cold , and that when the star enters into the body of the mettal , and disappears , there are still remaining certain corpuscles of the planets of both mettals , which are interwoven in the middle of the mass , which makes this net , whereof the fables seem to leave us an idea : we must confess by the by , that there are certain things in nature which surpass our understanding , and that we ought not to imagine with our selves that we are able to satisfie all the learned in every thing . but to go on with this chapter , i observe likewise , as there are mettals which rejoice at the commerce which they have with the influence of some planets , so there are parts found in our body which correspond with particular planets ; as the heart with the sun , the brain with the moon , the liver with mars , the spleen with saturn , the lungs with jupiter , and the reins with venus ; so we see that gold , which is the terrestial sun , is a soveraign cordial , or a medicine for the heart , and truly universally for all bodies , as the coelestial sun is for the whole world ; as i shall shew when i come to discourse of mettals silver in the same manner is a cephalick medicine , whereof are made wonderful remedies for diseases in the head ; the same may be said of iron in respect of the liver , when it opens its obstructions , and fortifies ; copper affords a spirit which wondefully heals the reins , and also venerial distempers . i shall speak something of every mettal in its proper place , and we shall more plainly see how every mettal doth administer a specifick remedy for that part which it hath relation to , as experience shews . as for sudorificks , i will not speak of them . medicinally in this place , neither will i explain the matter whereof those remedies , so benificial to mans body , are made . it is sufficient for me to speak of them philosophically ; and it being supposed ( which i have not seldom seen ) that one only grain of powder plainly insipid , and of the colour of calcined gold , given in half a glass of wine , doth provoke sweat in abundance from the whole body from head to foot , without any violence or alteration : this i have seen , and have done it , and can do it again at any time when i please . nothing remains , but that i should give the reason of this phoenomenon , and that we know whether it ought to be attributed to sympathy or antipathy . i suppose , and i know it very well , that this powder is compounded of the spirit of gold , and all other mettals reduced into one ; so that it ought not to be admired , that the atoms of which it is composed should be so penetrating , that they are carried from the stomach , through the whole body , and that in their passage they fix the most subtile corpuscles of humours , which pass through the pores in the likeness of vapours , and meeting with the cold outward air are reduced to the likeness of dew , which is called sweat. there are other sudorifick powders , but they are more violent , because they are less subtile , and less penetrating , and whose atoms are not so apt to rarifie the humours , and to draw them to the extream parts of the body with so much facility , and with so little danger , as that doth which we spoke of before chap. xii . of poisons , and toxicks . there are several sorts of poisons and toxicks ; some whereof do come at us with an infected air , others are communicated to us from animals , or some nutriment . it is not my purpose in this place to shew all the differences of them . it answers my purpose to reduce them to five , from the occasion of those things which i ought to speak of , about the antipathy that is betwixt poisons and our bodies . therefore i chuse three kinds of poisons or toxicks , and i shall endeavour to explain the manner how they act upon our bodies with the assistance of that fictitious antipathy , the refuge of ignorance : the first is the poison of the heart , because it immediately assails this part ; such is the poison of a viper , or the plague , the breathing of the infectious air draws and conveys the plague to the heart ; since we cannot say that the air is carried into the heart by a contrary quality , whence therefore doth this arise from antipathy , or repugnancy ? and after what manner doth the air , which gives life to the heart , and matter to the vital spirits , bring death to it ? which sometimes invades it upon a sudden , when the poison of the plague is violent , but ordinarily a man doth not dye so suddenly , and the poison only by the motion of the heart , disperses it self thro' the veins , and corrupts the whole mass of blood , and bubo's , and pustules arising are the marks of it : but when the poison goes out by suppuration , the person infected is sooner cured . it is very hard to say , what poison is , for if we say it is a contrary quality , or air corrupted , we talk foolishly ; we must know wherein that corruption doth consist ; if it be corrupted , it is no longer air , or if air be a corruption , it is a quality , so that still there remains the same difficulty : therefore to use no circumlocution , we say that deadly poison essentially is nothing but certain atoms or corpuscles , which are very acute , and crooked , figured like little piercers or small nails , which penetrates , cuts and divides the vital parts , and by this motion interrupts the motion of those spirits which give life . and that i may explain my opinion right upon this subject , i mention those things concerning poisons and atoms , which as far as i know , have not hitherto been mentioned by any body , which is , that poison is nothing else but certain loose and emancipated atoms , for many of such atoms being loosed and separated from the body we call poison . as to that , we are to observe , that being compounded in that manner which we are , our conservation doth consist in the composition , and as long as that lasts we live , and so our destruction doth proceed from the division and dissolution of our bodies , so that corruption is nothing but a solution of the body : this solution doth not happen but from emancipated atoms , who by their incomprehensible subtilty , do find an intermediant space in the most solid bodies , and if these be not speedily driven out and dissipated , or are repelled by certain aiding corpuscles , they will occasion diseases , griefs , and lastly death . therefore poison is not a pestiferous quality , nor is it the antipathy of the air , or of any thing , whereby they persecute our temperament ; nor is it corrupted air , but they are hard atoms which are set at liberty , and emancipated ; whence it does appear , how the plague may be brought to us from places remote within a short space of time , and how it may lye hid along while amongst cloaths in chests ; also the reason is obvious , why bleeding and purgation are not necessary in the curing of the plague , and why only cordials and sudorificks are convenient in a contagion . the same thing may be said of the poison of vipers , which is nothing else but some atoms divided and separated from the whole , which entring that part which is bit by the viper , do creep presently through the whole body , and divide , separate , and cut it , and at last dissolve and confound it . it is therefare incredible , that that poison should proceed from a great cold , because there are bodies which are much colder , which yet are not poison ; besides that cold doth not so readily , nor from so small a beginning , destroy the whole natural constitution of man's body . therefore i take that to be which wholy destroys us , is to dissolve our body , and that nothing can dissolve it but free'd and emancipated atoms , whence distempers do derive their original , and death , the consequence of it : i say it follows , that it is impossible but that there is poison in all our diseases , and that we cannot enjoy a full and perfect health , as long as we have in us the least atom of that kind , which i say are emancipated ; these are so many enemies which we cherish in our bosome , being the principles of division , dissolution , and death . but some will ask , whence come these emancipated atoms ? who emancipates them ? and after what manner are they found in the vesicle , which is broke , where the viper bites , or in the spittle which enters our flesh by the biting of this creature ? i answer , that they are atoms not firmly complicated , which get abroad , or they proceed from some dead body which is dissolved into its first principles , as it happens with the plague ; some of them get loose , like servants who wanting a master , do seek to be busied and employed in some business , and as long as they stick to no body they may be called desolate and depraved atoms , which are continually moved , drive others , and dissolve them by their reiterated concussions ; so a little poyson doth suddenly extend and disperse it self through the whole body , because these atoms by their emancipation being made venomous and pestiferous to emancipate others , and confound the whole body , and in this sense it 's most true , what the physiicans say , that the corrupt humours of the body do degenerate into poison , because these moist parts of our body are more apt to break and divide than the solid parts of it ; they are also the first which begin to be corrupted and divided . i know not by what instinct of nature we commonly say when we apprehend any distemper , that we are ill composed , and of a body that is crazy and full of humours , that is wholly ill disposed , because in truth the emancipated atoms do disturb it , and hinder the union and composition of its parts , wherein the state of perfect health doth consist . some will say that i have handled this matter after a strange and odd kind of method , but if truth and reason confirm my explication , as i hope it does , they have nothing to say against me , but i speak those things which were never said before ; or that i do not proceed in the same manner , and the same course in the progress of this philosophical tract ; wherein i will sincerely endeavour to bind my self up to the truth , without having any regard to the prejudices of the schools . i return to poisons , and after i have discoursed of pestiserous and viperine poison which attacks the heart , it will be time to say something of those which immediately invade the brain , and from thence the heart , the center of life , before i address my self to either general , or particular antidotes , which deserve a particular chapter by themselves . therefore i say according to the common opinion of physicians , that there are toxicks and poisons which immediately beset the heart ; as i have said of the pestiferous and viperine poison , and others like them , there are others which attack the head , such as the biting of a mad dog , opium , solan , and other narcotick and somniferous simples . there are also poisons which rush into the liver , and corrupt the whole mass of blood , as the venerial poison , and others of the same kind . th●s diversity is ascribed to antipathy , and an aversion , whereby poisons are carried to certain parts of our body , but the foundation must be shewed , whereupon this antipathy is built ; the water sticks , neither can any solid reason be given , why the poison of a mad dog attacks the head , or that of the viper , the heart ; besides that this antipathy is not sufficient to explain the nature of poisons , though we may confess , that they have an aversion to our nature , because they endeavour the destruction of it , and do procure the separation and division of our bodies . it being supposed ( as indeed it is ) that a mad dog biting a certain part of our body , doth leave in that part a certain spittle or foam , which enters the wound ( for unless there be a wound , there is no fear of danger ) the venomous atoms being dissolved and emancipated , and as it were raving mad , do insensibly and by degrees creep through the parts of the body , and finding no softer parts than the substance of the brain , and by consequence easier to be divided and destroyed , do produce the dissolution of it ; and therefore it must be granted , that if the brain could not so easily be dissolved , and that the fluidity of its substance were not the reason why it so easily receives the impression , that is the action and motion of the emancipated atoms ; the poison of a mad dog would produce but little disturbance in us . it must not be said that that poison ascends the head by sympathy , and ruins it by antipathy ; but according to our principles , it ought to be confessed , that the atoms of the spittle of the mad dog , being loosed and emancipated , are as apt to destroy the other parts as well as the brain , if the substance of the brain did not consist of certain corpuscles , yielding to these foreign corpuscles , whereby they enter into the vacant spaces of them , which having entred in at these little chinks or fissures , they raise a tumult and confusion in the castle . this truth is evident in slow poisons , which stagnate as well as that whereof we speak , until the emancipated atoms of it find out some part , whose vacuities give them free entrance , or they meet with some corpuscles , whose little hooks or angles do either accelerate or retard their motion : for these emancipated atoms being not received nor fixed , but by weak corpuscles , are like a bird having only his feet entangled in the birdlime , endeavours with all his strength to get himself free , or like a man , who is to be thrown into prison , and is withheld only by one arm , uses his utmost endeavour to obtain his liberty ; so it is with free and emancipated atoms , which are partly withheld by these tender little hooks , whereof the brain doth consist , whence arises a furious agitation in the brain it self , and at length madness ; for indeed the madness is in the dogs brain , to which some emancipated atoms came from abroad , or from some dead carrion which the dog did eat , or from the air in the dog-days , being then too much rarified , or from too much dryness of the brain , proceeding from too much drowth , and these atoms go forth with the spittle , when the dog bites some part of our body , and in time produces the same confusion with that in the dog. the third sort of poison which i promised to speak of , is that of the venerial disease , which sets upon the liver , and without a prolix declaration of the external causes which produce it , it will be sufficient for me , if i will declare in few words , that which is necessary to know , wherein they do consist , and why poison is so pernicious , that it corrupts the liver , and infects the whole mass of blood , and afterwards , tho' slowly , ruins the whole constitution of the body , and the oeconomy of its constituent parts . it is frivolous to say , that the venerial disease and its poyson , doth consist in an antipathy to the liver , and the mass of blood , for the cause and nature of this feigned antipathy , cannot be assigned . but in my opinion there is no difficulty in the matter , for by the common consent of physicians , this poison is nothing else but a malign quality , proceeding from the vapour raised from the corruption of the spermatick blood , which corruption is occasion'd by a mixture of divers seeds . this principle being supposed , we do reject this feigned maligne quality , for it cannot be said what it is , or from whence this malignity arises , but we acknowledge this vapour , and admit the corruption of the seed , and we say ( not mentioning , the malign quality ) that there are certain atoms excited by heat and motion , which do exhale and free themselves from the loose and corrupt blood , and finding the pores of mans body , and of the natural parts to be open and dilated , do creep and insinuate themselves into them , and in process of time , do penetrate into the spermatick vessels , from thence into the great veins , and from thence into the great vessels and the liver , being the trunk of them , which they by dividing do alter , and by separating do corrupt , whence , at length there follows a corruption of all the blood. the subtilty and continual motion of these emancipated atoms , appears from the gout , sometimes from the reliques of the venerial distemper ; for these atoms do penetrate into the marrow of the bones , and fix them above the articulations , where they find an allumenous matter , to which they stick : but because these venerial and other emancipated atoms are not fixed , therefore they are moved in those places where they are , like a captive fetter'd in prison , looking about him , which way he can most conveniently make his escape ; hence it is , that the pain of the gout doth not cease until these atoms are discharged , either by transpiration , sweat , or some other evacuation , or that they are wholly accumulated by other bodies , of the same figure ; or that they are altogether stopped in their motion by a condensation of those alluminous matters , whence the gout becomes knotty and incurable . chap. xiii . of sublimate , arsenick , and other sorts of poisons , and the deadly effects which proceed from them . there are two sorts of sublimate , the one corrosive , the other sweet . the first is a most violent poison : the other is a most excellent remedy for worms in children ; however , it is not without some malignity , and therefore , it is given but in very small doses ; and as to the first , fortified by the corrosive spirits of salt and vitriol , the least quantity of it cannot be administred , without inconveniency , nay death it self . in this place we are to enquire , wherein doth that poison , which is so powerful consist ; for as soon as sublimate is swallowed down , it produces ulcers , blisters , and excoriation in the tunicles , or coats of the ventricle , they ●re seized with an inflammation , over-run with a gangreen ; and unless a good antidote be taken , ( as i shall shew hereafter ) death it self is the consequence of it ; but let us see by what malignity that sublimate produces these deadly effects , and wherein the force of this poison doth consist . that we may be able to comprehend this truth , and discover wherein the malignity of this poison doth consist ; it is to be supposed , that sublimate is an artificial poison , being a compound of the most subtile particles of quick-silver , salt and vitriol , sublimated together , in the form of crystal or white powder , like sugar : so that the venomous and corrosive sublimate , is made neither of quick-silver , salt , or vitriol alone , and apart , but there ought to be the spirit of salt and vitriol to separate the quick-silver , and that though before it was fluid like water , is to be reduced into dry earth ; which is done by reason that these two spirits do separate the mercury in the sublimation , and in some manner kill it , and do penetrate it , as if they were poison to the quick-silver it self , they corrupt it , and force it to change its disposition , because they divide it , and reduce its corpuscles into small stings , whence it is that they are so sharp , penetrating , and corrosive : which doth not happen , if the quick-silver be sublimated by it self ; for then it ascends in its own fluid and gliding nature , and in this manner it may be taken inward without any danger , and also when the sublimate is sublimated with crude quick-silver . this being supposed , i conclude , that sublimate is a poison which suddenly operates in our body , to the destruction of it , because its corpuscles are reduced into stings , like the corpuscles of fire , salt , and vitriol , which does sharpen the corpuscles of the quick-silver , wherefore they produce the same effects in the body , as fire or the caustick stone swallowed do , for it presently burns every thing that it touches , and ulcerates the whole stomach , gullet , and all the parts through which it passes ; because its corpuscles being so sharpened , do penetrate and dart thro' , like flames of fire ; therefore antipathy hath nothing to do in this place , no more hath that feigned maligne and occult quality , as the less learned would fain alledge : all that is observed concerning this subject , ought to be ascribed to the disposition , subtilty , and figure of the corpuscles , which renders them corrosive and burning . the same thing may be said of arsenick , except only that arsenick , is the work of nature , and sublimate that of art ; for in truth , arsenick is a perfect mineral which is found in the earth , and sublimate , is prepared by artists in sublimatory vessels . the effects of arsenick , as well the white as the red , is near the same with those of the sublimate , and both of them by right may be ranked amongst the most prompt and violent poisons , in respect of the sharp and penetrating particles , whereof they do consist . there is nothing which disappoint these effects , except proper antidotes made use of in time , which change this disposition , and blunt the sharpness of those corrosive corpuscles . nevertheless , by special preparations , those venomous corpuscles may be taken away , both from the sublimate , and the arsenick : and by our fortifying and changeing of the compound , a most excellent remedy , for the health of man , may be made of the most pernicious poison , as the triacle is made of vipers flesh , which is the best antidote , as we shall see in the following chapter . chap. xiv . of antidotes . art , together with nature , supplies us with as many sorts of antidotes , as there are poisons : the viper , no less than the scorpion , carries its antidote ; if the serpent begins to creep out of the earth , nature affords us the leaves of ash ( which buds at the same time ) to heal its bite ; the same ground which bears a thora , hath also near an anthora , which is its antidote . there are also external antidotes , which do avert the plague , and preserve the body from the conragion , as we said before , speaking of amulets , where we did declare how this may be done , and how the body may be preserved from every malignant air , without any fictitious sympathy or antipathy . antidotes are general , and special , or specifick ; they are general which resist every poison ; they are particular , which are appropriated only to certain poisons . that it may be rightly explained how antidotes do work upon poison , and how they hinder its operation , we must suppose , that all poisons and toxicks , are reducible to two kinds ; the first doth consist of emancipated atoms , which are properly poisons ; under the second , are comprehended toxicks , as sublimate , and the like ; and that consists in sharp penetrating , cutting particles , such as the particles of fire , which burn , ulcerate , and tear the inward parts of the person who takes them : these things being supposed , it will be no hard matter to explain the nature of antidotes . having made this difference between poisons and toxicks , it is certain , that there are antidotes against poisons , and that they are diverse , according to the diversity of the toxicks : hence we see that triacles , of all the antidotes which we have , is most proper , and most specifick against the poison of vipers , because triacle is made of vipers flesh , and the emancipated atoms proceeding from it , finding the particles of that flesh , sit to receive them , do adhere to them , and are imbodied with them , and in this manner losing their motion , they lay aside their malignity , and remain fixed and quiet , in the same condition as they were , before their emancipation , they can no longer offend the heart , or effect any division of it ; so it is in the case of pestilent poisons , which we draw as we suck in the air , wherein , after a great contagion , these emancipated atoms are found , and with whom , they enter into our bodies . triacle , and cordial confections , are commonly used ; whose corpuscles are disposed and figured in such a fashion , as that the pestiferous atoms , running through all the parts of our body , are connexed with , and do wholy adhere to them ; whence there is a full and absolute cure , or partly ; which allays the violence of the distemper : but without doubt , or contradiction , the true antidote of the plague , is changing of the air , or correcting of it by good scents , which being attracted within us , together with the air , do attemper and correct it , and their corpuscles do check the impatience , and the too-free motion of the emancipated atoms . the poison of a mad dog is very hard to be cured ; and as that sort of madness is accounted incurable , and is publickly attended with a very deadly and fatal issue , we are forced to bind those who are infected or suspected , and at length to smother them between two feather-beds . the ordinary remedy is to send them to the sea , to throw them into it several times : experience teaches us that that kind of remedy is not altogether useless , but is to be accounted amongst those which are most safe , though it be not altogether infallible . the antipathy of the sea-water hath no room here , and it were vain to alledge it in the confirmation of this practice : therefore i say , that , according to our principles , the emancipated atoms proceeding from the spittle of the mad dog , while they penetrate the substance of the brain , or at least begin to penetrate it , or to be turned round its foldings , to enter into its cavities , are interrupted in their motion , so that they cannot enter into the cavities of it , nay and they are thrown partly out by those struglings which the patient must necessarily suffer when he is cast into the sea : i do not , nor will not deny , but that there are atoms or corpuscles proceeding from the froth of the sea , which entring into the patients body thro' the pores , made open by the agitation , or by breathing in of the air , and being comunicated to the blood , do with their cubicular figures , fix and withstand the emancipated atoms which produce the madness or nearly dispose the body to it : to comprehend in a word all that can be said concerning this matter , whatsoever can heal or give ease to a distemper so dangerous , it does it only by hindring the motion of those loosed atoms , or by quite expelling them out of the body . the same thing may be said of the third sort of poison , that is , the venerial , which is called the french disease , that also hath its general and specifick antidotes : quick-silver is commonly used for this business , and that by reason of that antipathy which is betwixt it and the disease , it is most certainly held to be the one only remedy for it : others use sudorificks , as guajacum , salsaparilla , or animal or mineral bezoar , or the salt of vipers : others are only contented with one remedy , which is mercury perfected by nature , and radically divided by art ; also the more industrious do use philosophical water , prepared from the beams of the sun and moon . but tho' we may provide an excellent remedy against this distemper ; nevertheless it must be confessed , that it is not radically taken away , but by the help of those things which expel the venerial emancipated atoms , from the centre to the circumference , whether it be done by sweat , or by an insensible transpiration ; this doth not happen by antipathy , or some occult quality , but by the motion of the particles of the medicine , which strike against these miserable atoms , and drive them out by those most convenient ways , that is , the pores of our body . therefore let us proceed to those antidotes which are opposite to toxicks , not by antipathy , or some occult quality , but by their different figures : therefore who will say that milk hath an aversion to sublimate or arsenick , though it be a most speedy remedy , and that no less than oyl which doth resist poyson , because descending into the ventricle , and in its passage touching the gullet and the orifice of the ventricle , as well as milk doth lessen the motion of the corpuscles of the poison , and blunts the sharp points and corners of them , and defends all those parts . but of all things a vomit is most useful in this case , being assisted with the help of milk , or oyle slackning the tunicles of the stomach , and making the passage more easie : for if a vomit should be given without smoothing and besmearing the passage , the venome in coming out would excoriate all the parts that it touched , by its sharp-pointed , saw-like , and hooked particles ; which are covered by the particles of oyl or milk going out with them , and are so prohibited and hindred from hurting . in the conclusion of this chapter i do observe , that corrupt humours in our body ( as physicians do affirm to us ) do degenerate into poisons and toxicks , but they are silent as to the reason of this confusion , and all the manner of avoiding it . first , they ascribe this corruption to external causes , or to inward occult and maligne qualities , or to the excess of certain qualities , ( as cold , hot , dry , moist ) or to certain unwholesom diet , and to ill digestion , or lastly , to obstructions , hindring the necessary distribution of them : but truly it is not demonstrated from thence , that crude and an undigested diet , or corrupt humours , do degenerate into poison , therefore the true cause of this thing , and the solid reason of it , must be enquired into . to this purpose , i do suppose , that the humours or nourishment being any manner of way divided , may be said to be corrupted , because i acknowledge no difference between a division and a corruption of a thing ; but in a separation which is not total , there remain some bodies which are neither poisons , nor toxicks , though they oppress and obstruct the parts , and hinder the intercourse of the spirits , as it happens in phlegm , melancholly , and slimy humours , which are joyned with the earthy part of the excrements . besides these bodies , there are other corpuscles which with their hooks , sharp points , and stings , do pierce , prick , and penetrate man's body , and the membranes of it , as also the veins , muscles , and nerves , and do corrode the stomach ; and in the same manner with poison , do occasion ulcers , imposthumes , and pustles . these are those which the physicians do call sharp , biting and chollerick humours ; whereof ( that i may end this tract concerning sympathy and antipathy , and the actions depending thereon , and without these occult causes assign a true and an efficient cause of all our distempers ) i am compelled to treat in a chapter by it self , and in that which follows shall be delivered the general means whereby the causes and roots of all diseases may be removed . chap. xv. the true cause of our diseases . the effects of our diseases are pernicious , and have their origine either from within or without ; the causes of them sometimes are so obscure , that the original of them cannot be discovered ; and though we define a disease to be a disposition against nature , or an inordinate constitution of those qualities which are constituent of a right temperature , yet for all this , we are not wiser or more learned than we were before : therefore after i have discoursed physically of the causes of our diseases in general , it will not be amiss to trace òut the particular causes of them . that this doctrine which may be accounted new , may the better be understood , i suppose , that we are never subject to any disease , but whose immediate cause is either some poison or toxick . ly . this poison consists only in emancipated atoms , and toxicks in loosned corpuscles . ly . these atoms are not emancipated ; nor these sharp corpuscles loosned , but in the corruption of bodies , ly . corruption is nothing but a total or partial division and separation of bodies . ly . there is no new generation by which a new body is made , but by a precedent corruption or division of another body , which ceases to be in nature , when one or more other bodies possess the room of it . so when meat in the stomach is turned into chyle , when the chyle in the liver , and the branches of the vena porta is changed into blood , and lastly , when the blood is changed into our substance , as flesh , muscles , nerves , and other parts of our body , by the last degree of concoction , there is necessarily a corruption of the meat , which begins to be divided and separated by chewing of it in the mouth , and it is digested and separated , or corrupted in the ventricle : chyle , to the end it may be turned into blood , is altered in the branches of the vena porta , and the meseraick veins ; and thence it is wholly and perfectly digested , that is , corrupted , concocted , and divided in the liver , unless that hath lost something of its own substance . the blood designed for flesh , is filtred out of the veins into the arteries , and circulates until it be sufficiently purged , and freed from foreign bodies , and then it is changed into the substance of our body . this doctrine being supposed , i say there are made in us three principle corruptions , which are the concoctions or digestions whereof we speak : and i say moreover , that there are atoms in every one of them , which are emancipated and loosed , as likewise corpuscles , flying and deserting more or less , as the digestion is the better performed , that is , as the pure is more rightly separated from the impure . therefore it follows , that we cannot be nourished , unless we take together into our bodies the causes and seeds of many diseases ; it follows likewise , that these diseases are diverse , according to the difference of the corruptions of the emancipated atoms , or the loosed corpuscles , and that these atoms are poisons , and the corpuscles toxicks , which do produce diseases by their violent motion , and they labour so with reiterated corruptions , that they deprave , separate , and divide all the parts of our body . here we may behold the just cause of the pains of the stomach , and of the wind chollick , and also of the wind proceeding from the first concoction of our meat in the stomach , these winds are the corpuscles or the more subtile parts of that corrupted nourishment ; and when the more subtile and sharp corpuscles are received into the body , they do , proportionably to the nourishment which is taken , produce most troublesome and dangerous pains , and vellications , such as we observe in the chollick . and if it should happen , that amongst corpuscles there should be abundance of emancipated atoms , they do ordinarily betake themselves to the brain , whence do arise apoplexies , and lethargies ; or if they penetrate into the muscles and nerves , they occasion the palsie , which ordinarily follows these bilious chollicks . this indisposition degenerates the disease into a vomiting , and loosness , when the wind or the subtile particles , the loosed corpuscles , and the emancipated atoms are so plentiful , that all the symmetry of the humours , the intercourse of the natural spirits , and the whole anatomy of the body are overthrown by them ; whence it is conspicuous , what great confusions , winds , vapours , and little bodies , and depraved atoms are capable of producing in our bodies : and that i have concluded upon good reasons , that there is poison to be found in all our diseases ; whether we consider them in their beginning , when we perceive our selves grieved , indisposed , and to have lost our appetite ; or that we take a view of them in their progress , when those winds , those little bodies or little atoms are advanced in the body , and do work a division ; or lastly , if we consider the end , when these poisons and toxicks , and these corpuscles being freed from their chains , and these emancipated atoms bear the sway , by the confusion of the principal operations , they are the cause of death . in the second digestion , which is in the liver , we find winds and vapours , which are called flatus's ; and sometimes those loose corpuscles , and also the emancipated atoms ; these winds do produce a murmur and flatus about the liver , spleen , hypocondria , and the reins ; and the corpuscles which are lodged there , do prick and exulcerate the inward ●●rts , and are the causes of imposthumes , which are so hard to be cured . besides the emancipated atoms flying , do sometimes ascend up to the head , where they beget vertigo's and buzzing in the ears ; and also convulsions by their vellications in the principal of the nerves ; thence proceed epilepsie , and other diseases , which have the same malignity ; which in the opinion of all men , being not a quality , is a poison , that is , the atoms of the blood are emancipated , which are a poison to the brain , and especially to the membranes and nerves . from the same fountain proceed shakings , and the duplications of continuant fevers , as the periodick fits of intermittent fevers do happen from loosed corpuscles and atoms which are emancipated in the first digestion in the stomach , by reason of a fermentation which they make . these loosed bodies are also the causes of swellings in the feet , hands , and other parts ; as inflammations , erysipela's , as also itch and sore puscles do arise from atoms which are emancipated in the last digestion ; as for the dropsie we may say that it derives its original from atoms which are emancipated in the first and second concoction , for they penetrate the substance of the liver , and render it unfit to produce a well constituted blood. sudden death is often occasioned by the sudden motion of the flying atoms , which escape in the circulation of the blood ; and the emancipated atoms opening the heart , and by this passage giving an opportunity to the vital spirits to make their escape , is the cause of that present death which follows it . chap. xvi . of the causes of our health . if that be true , which i suppose , that all our diseases do not arise from natural qualities , nor from antipathy , which is in the nourishment we take ; and that they are nothing else but a confusion , and an inordinate constitution of the spirits , humours and parts , and that this confusion doth proceed from the impetuous and disorderly motion of the winds , corpuscles and emancipated atoms , as i said before : then it is certain that our health , which consists only in the just intercourse of the spirits , and a proportionate mixture of the humours , doth not proceed but from things constituting and preserving this just temperament , and by the same it is conserved . as there are many things which destroy health , so there are also a great number of those things which restore and confirm it . the things which destroy it , are those which rarifie the humours , and occasion winds which dissolve bodies , and do emancipate atoms : those which restore it , are such things , or such remedies , which hinder the division , rarefaction , and dissolution of the humours and parts of our body , or since it happens that necessarily there is a corruption in every digestion , and a division of the aliment , chyle , and the blood , as we observed before from the same principle , it necessarily follows , that every thing that preserves health , hinders the alteration of it , and also restores it , being lost , which drives out of the body these winds , these corpuscles , or these injurious atoms : and that also which removes these seeds , or internal principles of our diseases out of our bodies , doth not produce that effect by a certain vertue , or physical quality , or by a certain antipathy , as it is said of rubarb and senna , but by motion and action which is made upon these rarified bodies , these loosed corpuseles , or emancipated atoms , proceeding from every digestion in the bodies of those which are most healthful . this motion is performed either by purgatives or emeticks , or by sudorificks , the two former of these are fitted to eject those which arise from the first and second digestion , and sudorificks do expel corpuscles or atoms of the third digestion , but here is no room to shew the differences of these remedies ; however we must trace out the manner of those operations . i said a while that medicaments do operate only by a vellication of membranes , nerves , and fibres , and which is produced by sharp corpuscles flowing from the medicines , and sticking to the aforementioned parts , whose motion is communicated to the subtle foreign bodies , that is , the excrements of every particular digestion , whereby these matters are driven forth the nearest and most commodious way for evacuation . i 'le make an end of this chapter , with an example of a familiar remedy , by means whereof every man may preserve his health , without either bleeding or purging ; nevertheless , i do allow that bleeding sometimes is necessary , and very useful to evacuate those emancipated atoms or corpuscles , which are loosed in the veins , from the digestion in the liver , especially when they being shut up , and cannot find their way out , they stick to the pleura membrane , and prick and vellicate it , and thereon produce an inflammation , known by the name of pleurisie , therefore in this distemper , as also in continual fevers , bleeding and sudorificks are by no means to be omitted . the same thing may be said of using purgative remedies or emeticks , to evacuate earthy excrements , as flegme and slimy humours arising from the first digestion ; and also serosities or choller , and melancholly being the excrements of the second concoction , but because the defects of the first concoction are not mended or repaired in the second ; and the first is more perfect , as the ventricle is more pure and more clean , and cleared of that viscous flegm which disturbs its action , and hinders digestion . without either envy or prejudice , i do here produce a vulgar remedie as most useful to preserve or restore health , if it be rightly used as it should be , as i have found it by experience , besides that it manifests the truth of my principles , which supposes every evacuation to be made by motion and vellication of the sharp corpuscles or penetrating atoms . therefore i take every morning a goose feather ; fit and slender , as it is in its own nature , i put this gently into my mouth , and i thrust it further to my jaws , and hold it there for some time , and i draw backwards and forwards , and i perceive a vellication made by the feather on my jaw , palate , and the other parts adjoyning , and likewise after this vellication , i do observe that water , phlegm , and viscous humours , being dissolved , do flow in great quantity for the space of a quarter of an hour ; and all this is done without any violence or danger , hereby i find that the head is lightsome , and the stomach freed and disburthened , and that thereby the appetite is increased , and that the corpuscles which before ascended to the brain by way of vapours are evacuated , incarcerated , or involved in the viscuous humours which are flowing , and afterward the first digestion is better made ; and it is evidenced by experience , that as the ventricle is less burdned , so our sleep is longer , sweeter , and less interrupted : were it not that i fear to exceed those bounds which i proposed to my self , i could make many useful observations upon this subject . but i must remember that i do not speak of medicine , remedies , health , and diseases , but by chance and occasionally , and it is sufficient , if i oblige the publick and the learned with the doctrine of atoms , and that i be helpful to them as well as to the sick , by the means of those remedies which i discover , and which i freely propose : and though i offer many things which were neither said , taught , nor writ before ; nevertheless i beg the readers pardon , for that i add no more to this matter , for i am afraid if i should , to be tedious to him , and if i have enlarged my self too far , i hope he will forgive me ; it were hard to say less of these things , except a man would say nothing at all of them , besides that it is grateful to every man to speak and write of those things which he loves , and are agreeable with his profession . chap. xvii . of formal , exemplary , and material causes . form and formal cause is one and the same thing ; and when we say there are two sorts of forms , that is only according to our manner of conceiving things . so we say there are two sorts of formal causes , the substantial and accidental . but all these forms are imaginary , neither do true philosophers acknowledge any other substance to be in natural compounds , than matter , except only in man ; nor any other form than the disposition of the parts , because all these forms are altogether useless . moreover these great sticklers for forms , cannot say what they would mean by a substantial or accidental form , therefore we do with a great deal of justice lay aside these fictitious forms , as being but chimeras , and of no use . the exemplary cause may be referred to the formal , because it is the idea and inward form of that which we frame in our spirit ; so the formal cause of a picture , is the disposition of its parts , according to the disposition and ordination which it then had in the spirit of the painter . the same may be said of all rational agents , which are endued with understanding . there is no difference be twixt matter and a material cause , and there are two sorts of material causes , as well as of matter ; that is the first matter , out of which all bodies are composed , and into which , by an universal division , they may be reduced ; the second , is nothing else but bodies made of the first , and upon which the efficient causes do exercise their activities . therefore it is apparent , that there is nothing in the world , but what is a compound , and that there is no compound without matter : it is also certain , that there is nothing made without an efficient cause , which acts upon compounds and destroys them , that of them others may be made ; because the matter of the first , serves for the composition of the second ; the matter which goes to the composition of the first and second , is the first matter , or material cause of the compound , and that matter which serves the efficient cause for a subject and patient , is called the second matter . both of them may be an efficient cause , for compounds do act upon one another , as the elements which drive one another backwards and forwards ; that which drives another is called the agent , as that which is driven is called the patient ; and if there be any thing which resists it , and drives back another , this regress of the motion is called a reaction ; so one and the same thing , may be the subject and cause of motion ; and that to give and receive , being the principle of agent and patient , may be at the same time , but in divers respects . chap. xviii . of the first matter . all philosophers do unanimously agree , that there is a first matter in the world , which was produced from the beginning , and tho' it can never be altered by any change , yet it is to be seen in all the generations and corruptions which are in nature ; this doth suppose , that the first matter did exist before the generation of the compound wherein it is found , and that it still remains , and survives the corruption of it ; as fire is made of chips , the matter of the fire was in the chips , and it is found partly in the fire , partly in the smoak , and partly also in the ashes : it is agreed by all men , that nothing is made out of nothing , and that there is nothing in nature , which can be reduced into nothing , so that the first remains one , and the same in all the revolutions which do happen . therefore in respect of matter , we may justly say , that there is nothing new in the world , since the creation of it , and that this matter , in its nature , is incorruptible , so that to explain the essence of this first matter , is all , and the one only difficulty : if we hearken to aristotle , he makes it the subject of all forms , and that it is nothing but a passive power , or a meer capacity of producing , and receiving them in its bosom ; he says in another place , that matter in it self hath neither quality nor quantity , nor any essence , beside that which it received from that form which perfected it : but this explication gives us no idea of matter , neither doth it teach us any thing of the nature of it ; on the other hand , according to this doctrine , we may say that matter is something , and we may say at the same time , that it is nothing ; and that it gives that being to form , and receives the same from it ; and lastly , that it hath distinct parts without any quantity ; which seems to be impossible . they were more in the right , who said , that the first matter was nothing else but the first elements , into which compounds by a total dissolution are reduced , also these elements ought to be simple , and indivisible , for otherwise , the first elements are not such as we suppose them to be : it follows , from this doctrine , that neither water , nor air , nor earth , nor fire , are the first elements of things , because they are compounds : therefore we must look out for other elements , which are simple and indivisible ; those things which the chymists would fain establish , that is , salt , sulphur , and mercury , cannot be taken for the first elements of bodies , since they are but compounds of many other bodies . i am of the same opinion concerning descartes his three elements , which he would have to be the principles of things , which is impossible , because they are divisible . therefore we must acknowledge , that only simple and indivisible atoms , are the first matter , and first principles and elements whereof bodies are composed ; out of these atoms are corpuscles made , out of these corpuscles small masses , out of masses greater parts , & then of these parts greater bodies , whereof the universe doth consist ; in the same manner , going backward in an analytical method , the world is divided into great bodies , those into parts , parts into small masses , masses into corpuscles , and lastly , these corpuscles are divided into atoms . chap. xix . of atoms and their nature . that we may solidly evince the existency of atoms , we must suppose , that every compound may be divided into so many parts , as there are which make the compound , therefore division ought necessarily to cease , when there is a failure of parts to be divided ; on the other side , there is no end of it , as long as there are particles to be divided ; one of the two we must allow ; that is , either that a body cannot be so exactly divided , but that there always remain divisible parts in infinitum ; or , that there are parts after a certain number of divisions , which will not admit any further division ; aristotle stands for the former , but gassendus and the ancient philosophers do defend the latter and according to this last doctrine , after all the divisions are made , nothing can remain besides atoms , that is , indivisible beings , which are the first elements of natural bodies . i confess , it is hard to imagin a corporeal thing to be indivisible , because we see nothing in this world , which is not divisible , but this makes nothing against atoms , which are corporeal , because they compose bodies , and are indivisible , because they are the first , and most simple elements of bodies : hence arises another difficulty , because it cannot be easily explained ; after what manner a thing that is divisible , is composed of parts which are indivisible . impartial minds do not find so much difficulty in conceiving this matter , as those do , who follow the prejudices which they have received : first , these men who are thus so prepossessed , do not consider , that there are many things which escape our senses , and yet are most real . secondly , they do not consider that that which composes a body , is not a compound , as we see that unity makes number , tho' it self be not a number : letters , whereof nouns and words are framed , yet are neither the one nor the other . the drops of water whereof rivers do consist , are not rivers ; so atoms though they are invisible and indivisible , yet they compose bodies which are visible and divisible . aristotle and his followers , do teach us , that a small body , as for example , a millet seed , is divisible in infinitum , and that it contains an infinite number of parts ; which being supposed , it may be concluded , that there are as many parts in the millet seed , as there are in the whole terrestrial globe : also according to this opinion , we must grant , that a body cannot be divided into as many parts , as really it may , and that neither the hither or further end of a staff can be found , nor that there is a circle or perfect piramid , nor that the parts of a body can be immediately divided . all which consequences as they are absolutely necessary , so they are all equally absurd . descartes did endeavour to free himself from this difficulty , by saying that the number of the parts of the millet-seed , was neither finite , nor infinite , but only that they were indefinite : but the evasion is ridiculous , and these two philosophers are forced to confess , that every part of the millet-seed hath its extension , and if their number be either infinite or indefinite , then their extensions also will be either infinite or indefinite at the least , which is absurd to affirm . i add no more , to avoid scholastic intricacies and distinctions . chap. xx. the properties , magnitude , figure , weight and motion of atoms . an atom is a corporeal being , simple , invisible , and indivisible : solidity constitutes its essence , or essential property , which distinguishes it from spirits and vacuity , which have no power of resisting . atoms do necessarily avoid all our senses , because these are composed of many distinct and gross parts , whose object ought to be composed , e're it can be perceived by the external organ , which nevertheless doth not destroy the truth and reality of atoms , because small corpuscles do escape our senses , as we observe in dust which sticks to our cloaths , and also in the corpuscles of a ring , which is wasted and diminished by time and use , in the corpuscles of a stone , which is made hollow by the drops of water which fall upon it in divers occult parts , in a mite which cannot be seen without the help of a microscope , and lastly , in small corpuscles , which are seen to move in a chamber , by the help of the sun-beams ; that we may omit many others which are smaller , which without doubt we could see , if our sight was sharper , as i shall mention in my animadversions about experiments of miscroscopes . though atoms are most subtle and inperceptible , yet they have their particular extension , magnitude , and figure , from whence their differences do arise ; for the figure of some of them is round , as the atoms of water , oyl , and quick-silver ; others have cubicular figures , such are the atoms of sea-water ; and others are pyramidal , as those whereof nitre doth consist ; there are some which have sharp points like needles ' as fire , whence we are to suppose that there are others variously figured . this difference is necessary to distinguish compounds : and as these atoms , as to their solidity , or invisibility , and indivisibility ( which are their inseparable properties ) are alike ; so also if they did not differ in their figure and thickness , all bodies would be of the same likeness . weight is the principle of the said natural motion , insomuch as it doth resist a violent motion : that i mention here , that we may know whether motion of atoms hath an internal or an external principle , or whether weight be determined only to one motion , or that it be indifferently inclined to many : and whether the motion of atoms do tend to some center : and whether it be continuant or interrupted : and lastly , whether it be perpendicular or horizontal , parallel or declined , right or parabolical , or circular . in order to resolve well this difficulty , i suppose that atoms may be considered in a double state , the first state of them is before the composition of the bodies which are made of them , which may be called the state of liberty : the other is that which they have in the bodies which do consist of them ; which may be termed the state of obligation or servitude . if attoms be considered in their first state , their motion is perpetual : so that an atom that is loose and freed from any composition , is essentially in motion , which ought not in the least to be wondred at ; for motion in respect of a free atom , is the same that understanding is in respect of an angel● which is never without knowing , unless his intellect is bound and clouded . from this principle it is evident , that atoms are in continual motion , unless they are hindred , or that there is some obstruction in the way , or that there are other atoms resisting and repelling of them , or that they find such as will stick unto them , or that they insinuate themselves into the atoms of certain bodies , or or that they enter into some composition , whereby their motion is stopped . nevertheless , atoms in compounds are not altogether void of motion , because they are not so straitly imbodied together , but that they have some motion , like vibrations and palpitations , according to the liberty which is granted them by the disseminated vacuities ; nay , some of them sometimes do attempt their escape , especially in porous bodies , which therefore are sooner corrupted and perish , than other bodies which are more solid , and more close . it is yet more evident in living bodies , out of which the animal spirits , which are but the bodies of atoms , and most subtile corpuscles , are dissipated by transpiration , whence aliments are necessarily requisite , for to supply the spirits of the whole body , which are dissipated by motion and agitation . this motion of atoms , or the least corpuscles , in living bodies , may be deservedly accounted the image of their first liberty , and tho' they do but seldom enjoy their full liberty , yet they are apt to raise the greatest commotions , in order to be freed , and to gain their liberty ; this is the origine of many distempers , as in acute fevers , the atoms or corpuscles of the boiling blood , or obstructed choller , are carried and driven into the brain , where they produce watchfulness , deliriums , and phrensies . according to this principle , that which we said before may be concluded , that many distempers do arise from minute corpuscles , and emancipated atoms . for these being driven forwards by other atoms , and forced back , do run into the membranes , periostiam , meninges , or intestines , and cause pains , which they call the collick , headach , gouts and rheumatisms ; so that this solution of corpuscles , and emancipation of atoms in our bodies , are much to be feared , and to prevent this danger , all motions of the body which are too violent , must be avoided ; for these are the external cause of the confusion of the spirits , and the emancipation of the atoms . the emancipation of atoms , and also of the small corpuscles , which are composed of those atoms , are to be feared no less in the great than little world , for the winds are nothing else but emancipated atoms , which by their impetuosity , being driven backwards and forwards , do force all bodies which they meet with in their way : it is these atoms which agitate the air and the sea , and cause earth-quakes , and also over-turn all things which resist their motion : therefore , the motions of atoms , are neither equal nor every where alike , but they do vary according to the diversity of bodies whereby they are driven , or as the figures of them are more or less fitted for motion , or otherwise , according to the proportion of vacuities , which are dispersed in bodies ; so that some atoms are moved quicker , and others slower , not because some are heavier than others , but because they are driven backwards and forwards , or are stopped by others which do fix them , with the greater or less violence . chap. xxi . difficulties arising from the doctrine of atoms . the first which presents it self , is in relation to the being and nature of atoms , therefore it is hard to conceive , that an atom is corporeal and material , and at the same time , that it is indivisible , or that the same being indivisible , should at the same time have its grossness and extension ; but this difficulty proceeds from nothing else , but the prejudice of our senses , which can conceive no objects , but as they are divisible and gross , neither can they give to our soul , ( which is an indivisible being ) an idea of an indivisible thing . it is only our soul which is indivisible , as well as an atom , is able to conceive the nature of them , which being elevated above the senses , can correct the errors of them ; therefore i say that an atom is not a body , according to the notion which we have of it ; that it is a compound being ; but i affirm it to be a simple being , and also corporeal ; that is to say , simple , because it is indivisible ; and corporeal , because it hath a certain extension , and makes up the composition of bodies , which , in the total division of them , are reduced again into atoms . there are two other difficulties which do arise from the former , for , if an atom be indivisible , after what manner can we propose to our selves , that it hath extension , or how can it be an ingredient in the composition of divisible bodies ? to which it is answered in few words , that extension is according to the nature of the thing extended , for if the thing extended be divisible , in the same manner is the extension , and so on the other side ; so it is of the rational soul , which is possessed of the whole body , and exercises its operations in all the parts of it , nevertheless it is , like an atom , indivisible , and though it be divisible in respect of the space it occupies , yet it hath an internal extension , which is indivisible : it is the same thing which divines are forced to say of angels , and some philosophers , about their physical tumid points . but some will say , that atoms are like neither to souls , angels , or physical points , because they have parts , and these have none , because that which doth consist of parts is divisible , it follows also that an atom is divisible . to this difficulty , i answer with the divines , that angels and our souls , which are spirits ; and also with philosophers , that physical points which are material , have no real , but only potential parts ; that is , an angel and the rational soul , in respect of the operations which they exercise , and the space which they occupy ; and the tumid points , in respect of the space which they fill up : indeed an angel and the soul have two powers , whereof the one is the intellect , the other the will , which being no more but an indivisible substance , which are capable of understanding , and willing ; yet no man will deny but that they , notwithstanding their indivisibility ( which at least , is equal to the indivisibility of an atom ) do fill up a divisible space ; as no man can doubt , but that an angel can be at the same time in the four corners of the room , and likewise can be in the middle of it , and that it hath a foursquare figure , by communication with the four angles or corners , and that it can quit this , and assume another figure at its pleasure , which cannot be said of tumid points , and atoms , which are destitute of understanding and will : the rational soul being equally indivisible with an atom , angel , or point , doth wholly possess a great body , no less than it did then when the body was little ; therefore it does dilate it self without being divided , because in its nature it is simple and indivisible , and is without distinct parts . this is the opinion of aristotle , and indeed it is the most common opinion . but if the soul were not by its own substance extended through the whole body , and had its seat only in the heart , as empedocles would have it , or in the spleen and the stomach , as van helmont places it , or in the glaudula pinealis of the brain , according to cartesius , or in the striate bodies of the brain , where the common sense is , or the sense it self , as it is called by way of excellency , and in the callous parts , because there it forms the ideas of things , and judges of them , and in the cineritious part of the brain , because there it performs the functions of the memory , according to the opinion of duncane ; it is certain , that all these parts which are taken to be the feat of the soul , are divisible , and that they have distinct parts and figures ; so the soul , as it is indivisible , occupies a space or place which is divisible , whence i conclude , that the indivisibility does not hinder , but that a substance may have a certain indivisible extension , but divisible as to the place which it possesses , or that it may have angles and figures , in respect of place , though its substance essentially remain one , simple , and indivisible ; delugo and his followers , do apply this doctrine to tumid points ; and truly , i conceive i may take the same liberty to apply it to atoms ; from this principle , which is , that an angel , or the rational soul , are neither more simple , nor more indivisible than a material atom , as we have supposed it , and laid it down as a principle . to these i add , that it is not sufficient that any thing be divisible because it hath parts , but they ought to be physically distinct and joined together by a physical union , nor that each of these parts should be of the same essence with the whole compound whereof they are parts . but it is certain that the parts of an atom are not physically distinct ; for the one could neither be , nor cease to be without the other , no more than the two essential perfections of man , that is to be an animal and rational creature : and briefly the parts of an atom are the parts of a simple being , which are in unity , but not in union : and by consequence really inseparable ; which is no hindrance , but that the mind of a man may be able to conceive some kind of interval , and some diversity betwixt the parts of an atom , in the same manner as the animal and rational natures are represented in a man , as if they were two physically distinct things . gassendus reasons from another principle which is very solid , and built upon the solidity of atoms , but upon the insolidity of a vacuum ; he takes an atom to be indivisible because it is solid ; but that that solidity and bodies likewise are not divisible , unless by reason of the void spaces which are found in them , and which do desert the interval ; by which the body may be divided 'till we come to those bodies , which , having no vacuum within them , can be divided by no natural cause , because a vacuum having neither solidity , nor any power of resisting , is the passive principle of every physical division . by a vacuum i understand the intermediate space betwixt the parts : and as that which has not a passive principle of motion is immoveable , so also that which hath not a passive principle of division , is indivisible ; and that we may wholly silence all the cartesians , i do affirm an atom to be indivisible , because there is no interval in it , by which means some agent may divide it , in the same manner , that they deny that god is able to remove the universe , because they say there is no other place wherein it can be posited ; which i would willingly grant them , if there was no place without the world. it is necessary that they should agree with gassendus , if there be no interval in an atom . the question is , if three atoms be placed together in order , whether the middle one doth touch the other two which are on both sides of it ? this being supposed , it must have two sides , and two several faces . i also ask , whether an angel being immediately placed betwixt two angels , together with a third , in a straight line of three foot long , whether one of them be touched by one on this side , and by the other on the other side ? and since there is the same difficulty , it requires also the same answer . but i answer directly , and say , that all these , for example , square sides of an atom and their faces are not parts physically distinct , but only simple beings , and physically indivisible , as the philosophers do teach , that there is in man a principle of sense , and a principle of reason ; though these two are but a simple being , and indivisible like an atom , and the sole difference doth consist in the respect of their divers effects , and of our spirit , which finds an interval where really indeed there was none . chap. xxii . of the disseminate , congregate , and separate vacuum of gassendus . the doctrine of a vacuum is contrary both to the doctrines of aristotle , and cartesius ; the first was of opinion , that it was impossible that naturally there should be a vacuum , because , saith he , the universal nature is against it . the other ridicules this fear of nature , though notwithstanding he teaches that there can be no such thing as a vacuum in nature . gassendus on the other side affirms three sorts of vacuums , the first of which he calleth a dispersed vacuum , which he saith must necessarily be in all bodies , and this doctrine he endeavours to prove by motion , which cannot be done but in a vacuum : for that truly no body can be moved in a space that is taken up by another body , because there is no penetration of bodies , and therefore cannot be moved but in a void space . the cartesians do endeavour to elude this difficulty , by saying that there is a yielding , subtile , and fluid matter , which is not able to resist the motion of a solid body forcing the same . but that this is but a flight evasion , a poor shift , appears from hence , that this matter is uncapable of yielding , unless it were filled with small empty pores which are dispersed thorow , which being condensed and pressing themselves together , do suffer it to yield , and when it is condensed so far that there is no vacuum , it yields no farther , but it resists natural agents , though of great force . so we see air , condensed and compressed in an iron tube doth resist a staff which we endeavour to thrust into it , therefore air , which is a matter apt to yield , ceases to be so , when there are no more vacuums dispersed in it , neither can bodies enter into it , without a peneration of the dimensions : whence it appears , that there is no such thing as a yielding matter , and that every matter in its nature is equally solid and resisting . to this demonstration i add further , that not so much as a gnat cou'd in the least move it self , unless there was a vacuum in the air , ( which is a matter● of it self apt to yield , ) but that at the same time the region of the air , nay and the heaven it self must be in motion ; because if all things be full of bodies , the gnat cannot be moved but by driving the ambient air , which air also drives the next , and that again the next , and so in a right line to heaven it self ; and if the world according to cartesius's doctrine had no bounds , this motion wou'd have an infinite continuance , which wou'd be a thing both absurd and ridiculous in the highest degree . this philosopher did believe that he was able to elude this reason , by supposing this motion not to be in a right-line but circular ; but besides that the air is not moved but in that manner that it is driven , and that indeed it is forced in a right line , but not circularly , as it is supposed it ought to be moved , it is most certain that this circular motion , by altogether supposing all privation of a vacuum in this element , is impossible : for if there be no vacuum , all things are full : if full , the first part of this supposed circle cannot be moved , because it finds no place through which it can be moved : therefore it ought to remain immoveable with all other things , which are in the universe , unless there were a vacuum , through which it might commence its motion . gassendus builds the truth of these small dispersed vacuums upon the truth of the figures of atoms and their angles , because angles cannot but leave void spaces in bodies , as we see a great many grains of corn do leave void spaces in the bushel wherein they are contained , and do touch one the other . i confess that these vacuums are replenished with air , but vacuums which for the same reason are amongst the smallest parts of the air or atoms , can be replenished with no matter ; and if they be replenished with it , i do demand whether the parts of this subtile matter have figures ? which if they have , they cannot be united and joyned together without a vacuum , which if they have not , neither have they extension , nor are they material according to the very principle of the cartesians . to all that has been said , we may joyn an experiment about the rarefaction and condensation of bodies , and the confirmation of disseminate vacuums , for example , take a glass-phial with a long neck , which being well heated , put it into a vessel full of water , so that the end of the neck of the vial may go a little way into it , we shall certainly see that the water presently ascends to a certain height , as the air in the vial is condensed , and gives way . from this experiment i conclude two things in defence of a vacuum . whereof the first is , that the air is before rarified in the vial , and that the parts of it are more dilated : ( but this rarefaction of the air cannot be done but by the help of the great and more copious vacuums : ) the other is , that the water could not ascend in the vial , unless the air did give way , and was condensed : but air cannot be condensed , unless the parts of it close nearer together , and that they could not do without a vacuum ; therefore we must conclude , that air is condensed by the help of vacuums , which are partly taken away , and lessened as well in quality as in number ; as it happens in a bushel full of corn or salt when it is moved , by which motion it is not a little condensed ; and the atoms of fire beget a dilating motion to the air in the glass , but cold produces a condensing motion , and as it is condensed and becomes more gross , the aiery atoms do also draw the water as it were with small hooks , or the external air lying upon the water makes it ascend by reason of the vacuum which gives place , or at least does not resist the weight of the air. but perhaps they will say that there is no vacuum in the air , but that many particles of subtile matter do go out from the vial , and give place to the ascending water . but this answer gives no manner of satisfaction , because there is no body to force this subtile matter , neither is there any way through which it may pass , as also there is no cause assigned why the water is forced upwards . as to this , we must have recourse to the small empty spaces which are found in all bodies , which bodies are more or less fluid or solid , as they have more or less of matter or renitency , as there is the greater or lesser number of those vacuums , whereof we speak , dispersed through them . chap. xxiii . of a congregate vacuum , against aristotle and cartesius . gassendus is not only against these two philosophers concerning a dispersed vacuum , but also about a congregate one which is very remarkable , and is to be found about divers compound bodies . aristotle who fights for quality , or accidents distinct from substance , rejects a vacuum as a thing which nature can no ways endure . but cartesius speaks yet more hardly of it , for he affirms that the production of it in the world , does not only exceed the power of second causes , but even of the first cause it self . aristotle endeavours to prove his doctrine after this manner , to wit , that in his opinion a vacuum would interrupt and hinder the motion and action of natural causes : for if indeed light and heat be accidents , the sun could not produce either of them in a vacuum , or through it , though there was never so little of it in the air , equal to the least imaginable point ; for according to this opinion , they are accidents , and have need of a subject , which a vacuum does not afford them . descartes builds upon another foundation , for he acknowledges no difference between extention , and matter extended ; and therefore he affirms that there is no distance between two walls , betwixt which there is no air nor matter , but that they would fall close together : which how ridiculous it is , we shall see by what follows . i affirm therefore , that nature doth not abhor a vacuum , nor that it is impossible that there should be a vacuum in nature ; for indeed there is no ground for this imaginary fear , and the experiment which i bring , will most solidly demonstrate the existence of a vacuum . this experiment was made at clermont by the late mr. paschall , a man well esteemed by all that knew him , he took a glass tube four foot long , divided into inches and lines , open at one end only , through which being filled with quick-silver , and then put into an earthen vessel full of water and quick-silver , immediately the quick-silver that was in the tube did descend , and stuck at the height of twenty five inches , and five lines and a half , and remained visibly in that state for the space of five hours . this experiment was afterwards made in several places , two or three times , i , and several persons of quality and learning being present , and indeed every time it did more or less sink down , according to the highness or lowness of the place where the experiment was made , without any visible alteration in one and the same place ; i conclude , that the space which remains above the quick-silver , is a vacuum , and that nothing but light is contained within it , we must therefore say either that light is not an accident but a body , which fills the space , or else that this space is a vacuum , and that light is in it without its subject . it may be said that the glass being porous , the air or some other body more subtile , might enter into the tube , and replenish the space left by the descending quick-silver ; but that cannot be , because the quick-silver descends on a sudden , and the air could not so suddenly enter in without breaking of the glass : but if it did enter , why does not the quick-silver descend to the very bottom , but remain suspended at a certain height ? from this experiment it appears , that a vacuum , according to the conception which aristotle hath left us of it , is not impossible to be in nature . secondly , that the external air by its weight presses upon the water and quick-silver in the earthen vessel , for otherwise all the quick-silver contained in the tube , would fall down to the very bottom . thirdly , that the same air hath a greater pressure in vallies than in mountains , especially upon those that are very high , because here it is more subtile and rare , and more dilated by disseminated vacuums , whereby its weight is lessened , together with its strength and resistency . the opinion of cartesius is yet more ridiculous , who affirms , that a vacuum is impossible even in respect of the divine power ; which opinion is no less impious than it is rash , for no man can deny , but that god is able to reduce into nothing , the air that is contained in the vial , and also to hinder any other body from coming into its place . descartes says , that this hypothesis is impossible , and that if this air was annihilated , the sides of the viol would immediately touch one another , because says he , things betwixt which nothing interposes , do touch one another ; that is true , that when nothing was there , nothing could be there , or when things come together to be joined ; but we suppose here , that the parts of the vial remain in their first state , as indeed they do , if they are not any ways moved , which they do not , god almighty hindring ; and whosoever denys that god almighty is able to hinder this motion , and this contiguity ; in so supposing is ridiculous and rash , prescribing limits to god almighty's power . there is moreover a separate vacuum , that is , a space beyond the world , which some do call an imaginary space , in which god hath not indeed produced , but nevertheless can produce something . of this we will speak in the second part , which we now begin . the second part of physick . in which is treated of coelestial things which happen above man. the world in general is a theatre of the wonderful things of god , and a collection of all things which he hath produced , whereof the world is the lowest , and least noble ; but the heaven the most high , and the most noble ; we do now here propose to speak of this coelestial world , and of all those things which are above us . chap. i. of the immense spaces which are without the heavens . descartes hath absolutely concluded that there is no space without the heavens , because all are full of matter , and that the world is not encompassed about with bounds and limits , by way of a circumference . aristotle and his followers affirm , that the world is bounded by the exterior and convex part of the heavens ; and beyond that , there are void and imaginary spaces , in which there is nothing real . gassendus and his disciples are of the same opinion , concerning the limits and circumference of the world ; but he denieth that there are imaginary spaces without the heavens , and he says indeed , that they are vacuums , and yet nevertheless that they are real ; and this is it which he calls a separate vacuum . the opinion of renatus descartes is intollerable ; because the world is limited in its being , as well as in its duration , that is to say , by a fluid space , or by time ; it is therefore limited in respect of place , which is a permanent space which it possesses , even to the circumference , ( that is to the convex part of the heaven ) otherwise the world would be infinite , and absolutely immensurable in its extension ; and indeed if the world had not limits , in respect of time , or that the instant wherein it begun could not be found out , it would be eternal . in like manner , if we acknowledge no end of the world's extension , we may say it is immensurable : but if the whole world be immense and indefinite , as descartes would have it , if it hath neither figure nor extream parts , it must evidently follow , that it is infinite , for that which in all its parts is real , or hath any part which we cannot count its last , is absolutely and actually infinite in its extension : but if descartes will play with the word indefinite , and say indeed , that the world is indefinite , because it hath no end in its extension ; but yet from thence it does not follow that it is infinite . i would ask him to tell me the difference betwixt an infinite line , and an indefinite one , and also between the immensity of god , and the indefiniteness of the world ? for if the world is indefinite , the same thing may be said of it , that trismegistus said of god , to wit , that it hath neither centre nor circumference ; whence it follows , that this world occupies all spaces , and that it is immoveable , nor can it be moved out of its place , and that god cannot create another world without destroying this , because there is no room in which god almighty might place it . all which consequences are inevitable , and the principle of it more than rash . the opinion contrary to the former , which is gassendus's , and which we embrace , is more firm and agreeable to reason ; for it teaches that this world is limited in respect of place , and that it hath both a circumference as well as a centre ; beyond which there are void spaces , in which god almighty could produce another , or more worlds , greater , or equal to this of ours wherein we dwell , if he pleased . from this most true opinion it is concluded , that god fills by his immensity all infinite spaces , and that he is really in them , and that he is no ways limited by the circumference of the heavens , and that he can there produce another world , remote from this of ours ; and according to this hypothesis , this distance or that interval will have its dimensions , although void and immaterial , yet mensurable . from thence it is concluded , that since space is ( as indeed it is ) immutable and immoveable , it is the proper place of bodies , actually , or potentially as they do or do not exist ; for if a body be in it , the space is filled , otherwise there is a vacuum , as we suppose , beyond the heavens where there are no bodies , so that i say that the place and extension of bodies is a permanent space , in like manner as time the measure of the duration of things is a fluid space . chap. ii. of the heavens , and their nature . all that can be said of the heavens and their nature , relates to their substance , figure , number , and motion . the substance of them is the same with that of the inferiour world ; for there are not two sorts of matter essentially distinct , and all material bodies are equally solid and impenetrable ; in that the essence of matter consists : and although there be some kind of difference between terrestrial and coelestial matter , it cannot yet notwithstanding be thence concluded that they are of a several nature ; because all the diversity proceeds from this , that the atoms of the coelestial matter are more subtile than the atoms of the terrestrial matter , and more exact , more moveable , and more perfect in respect of their figures , and the more perfect bodies compounded of them , and their mass better united , and lastly , the whole body more compleat . this doctrine may be illustrated by the example of letters , for those which compose a word , and which are accurately delineated and written , do not differ from those which compose the same word , and are ill delineated and written ; the first nevertheless are better , more exact , and more elegantly formed ; which happens , in respect of the same hand which makes them , according to the difference of the pen or ink , or the design of the writer , who makes longer , or rounder , or after any fashion he pleases . i say therefore , that the heavens which declare the glory of god , differ as much from the earth , as a printed book from a manuscript . atoms like letters are the same in both , which although they are of the same author , do not agree in their figure and shape , because almighty god would have it so , in order to the fairness and beauty of the world. the figure of the heavens appears round to us : this figure is most perfect , and therefore accounted most fit for motion , and nothing perswades us to affirm the contrary ; but on the other hand , all things perswades us that the figure of the heavens is round , since it encompasses the earth which is round . and since we observe the stars to have their nocturnal risings and settings , which could never happen , if the heavens were not round . the number of the heavens cannot easily be found out ; there are some who say there are eleven , others reckon nine , but the greatest part conclude that there are only three ; that is to say , the heaven of the planets , which they say is wholly fluid , in which they swim like fishes in the water ; the next that follows according to this opinion , is the firmament , altogether solid , where all the fix'd stars are placed like so many golden nails , or diamonds set in blue ; but the third is the imperial heaven , the seat of the happy , partly solid , and partly fluid : because the blessed bodies ought to dwell in a place where they may move , and freely breath the air of paradise . this opinion seems the rather to be embraced by me , because it is most consonant to the holy scripture ; wherein we read that the apostle paul was rapt up into the third heaven ; whereupon , from thence he testifies that he was lifted up into paradise . lastly , the motion of the heavens is uncertain : for it is a received opinion , that the heaven of the planets , or at least the planets themselves are moved about the earth , as also the firmament with the fix'd stars . but others teach us , that the firmament as well as the sun is immoveable , and the planets together with the earth , as being a seventh planet , are wheeled about the sun. this we examine in the following chapter . chap. iii. of the stars , and their substance . as mettals and stones are the ornaments of the terrestrial world , so are stars of the coelestial ; some of which are called fixed stars , keeping always the same place ; other wandring stars or planets , always changing place , and in their reciprocal conjunctions and oppositions coming nearer , or going further of ; the first are fixed to the firmament or starry heaven , the others to the heaven of the planets . the substance of the fixed stars and planets is of the same matter with the heavens , and the earth , for there are not two first matters , but there are many differences to be found amongst the compounds of the first . between these compounds there are degrees of nobility ; even as we see upon earth , that gold is more noble , more perfect , and more precious than silver , silver than other mettaline bodies ; rubies , and diamonds than other precious stones . in the same manner it is in the heavens , where the sun which is the most perfect of the planets , and each star hath its particular splendour , which doth not happen from the diversity of matter , but from its depuration , which consequentially arises from its distance from terrestrial and opake bodies . how many different pictures can one and the same painter make out of the same colours , only by a different disposition of them ? how many different sorts of books can there be made out of the same syllables and words by transposing of them ? what then hinders , but that we may grant the author of nature power to make out of so many atoms diversly disposed , so many bodies differing in elegancy and clarity , as are the stars or planets ? the matter therefore is the same of the heaven and the earth , of the dirt under our feet , and the stars above us . whereupon a certain ancient and eminent philosopher said , that the things above are like the things below : and so on the contrary . and we know very well that gold , as precious and beautiful as it is , is of the same matter with lead , and there is nothing requisite to the making of gold , besides the depuration of the atoms which are its first matter . i do here endeavour to deliver an idea of the substance of the stars , upon an experiment grounded upon melted mettals , and yet flowing in the crusible ; for gold falling into aqua-fortis is like a black powder , silver dissolved with the same aqua-fortis , and precipitated by sea water , or separated by the means of copper-plates , is reduced into a calx , or white , or greyish earth : tin calcined , becomes yellow like oker ; likewise lead calcined , becomes yellow , white , black , and red , as we will ; copper is turned into verdigrease , or into a yellow and red powder , and in like manner iron into a red powder called crocus martis , where by the way it appears how compound bodies become different , and vary , without the change of their first matter , by an only separation and division of their parts , corpuscles , or atoms . yet if you take these mettals so calcined , each by it self , and put them into a crusible in a melting furnace , with a strong fire , this powder will return into mettal again , and shine and sparkle in the fire ; you see then that the same matter is in a threefold different state , for being a solid body , it is afterwards reduced to a powder , and then again it is turned into a fluid matter , melting and sparkling in the fire . and this is the thing from whence i frame the idea , which i promised , concerning the fixed stars and the planets ; for nothing better represents the nature of the sun and its substance , than melted gold flowing in a great crusible , nor nothing better represents the fixed stars , than the same gold melted in lesser crusibles ; there is nothing more like the moon , than silver melting in a crusible . the same thing may be said of lead , in respect of saturn , and of tin in respect of jupiter , and of copper in respect of the bright and sparkling venus : so also iron melted with the matter which fluxes it , leaves an idea of the planet mars , yet without this mineral which fluxes , it better shews its refulgent redness . so it may be truly said , that the sun is like melted gold , and the moon like melted silver ; and so of saturn , and the rest . chap. iv. of the magnitude of the stars , and their figures . since the substance of the stars is like melted mettal , it may be likewise concluded , that the same is likewise round , because a melted mettal is always round , unless it be hindred by the mould in which it is cast , or by the crusible in which it is melting , and since there is nothing that compels stars to assume another figure , than that which is natural to them , and which is the most perfect of all figures , which is most agreeable to the first matter , out of which they are made by the author of nature ; we ought to grant that they are round . as to their magnitude , astronomers represent them to be immeasurable , and they take their hypothesis from the rules of the opticks , and from the experience of those great optick tubes ; the invention of which is attributed to campanella , but the restoration and improvement of them to anthony de reïta , as appears by his book entituled oculus enoch & eliae . the sun is commonly taken to be an hundreed and sixty and six times greater than the earth , and the earth to be three times as big as the moon , and the other stars are some bigger , and some lesser ; i would not dwell long upon a matter so far above us , especially when i consider the weakness of all those things which astronomers tell us concerning them , and the dissention which is amongst the most learned about them . epicurus is quite of another opinion , for he says that the true magnitude of the sun and stars is not much greater than they appear to us ; because , says this philosopher , since we see them to have natural colours , it follows then , that we see them in their just magnitude ; and he adds , that we never see objects in their true magnitude , but when we discern their colour , figure , and circumference : he endeavours to prove this his opinion by the example of fire , which we behold truly as it is ; greater , or lesser , accordingly as it flames : and after this rate , fixed stars would not be much greater than they appear : the same thing may be said of the planets also , because they are less remote from us than the fixed stars . i should not much dislike this opinion , if it were not rejected by the whole world , and that the shades , paralaxes , and eclipses evince the contrary . therefore we embrace the most received opinion , and positively affirm , that the most experienced , with the help of all their optick tubes , are not able to delineate the true and just magnitude of the planets , much less of the fixed stars , whose shadow is small , and they a great way distant from the earth . chap. v. of the motion of the stars . aristotle endeavouring to avoid or shun all the difficul 〈…〉 which occur in great plenty , concerning the motion of the heavens , thought he was easily able to explain it , together with its swiftness and regularity by the help of an intelligent mover , sent by god as an adjutant form , to move , push on , direct , and order the heaven , and each planet in all their motion . this doctrine seems to be at once both very easie , and very clear ; for if heaven and the planets have really a kind of motion , ( of which there is no doubt , ) there is nothing more easie than to have recourse to an angel , who , by gods command , is the mover and directer of it . but we should sooner agree upon the point , by having recourse to god , the author of nature , and saying , that he as the first author hath impressed this motion upon the heaven , and the stars , from the beginning of the world , and that he doth continually conserve it as the first cause , by his general concurrence , without using the ministery of angels to perform it , which would be no more necessary , than to assign a helping angel to the motion of animals , and the vegitation of plants , which no ●an will go about to do , unless he deligns to make himself ridiculous . ¶ this opinion supposes the earth to be in the center of the world , immoveable , and that the heavens are wheeled about this center upon the two poles of the world : the asserters of this opinion do affirm , that the imperial heaven is fixt , and immoveable , of a round or square figure , and that the firmament observes the motion of the primum mobile ; and by the impression of it , is rapidly moved from east to west , together with the fixed stars which it violently carries along with it . as to the planetary heaven , they who affirm it to be fluid , do also teach us that the planets do likewise in this vast space move with the like liberty that fish do in the water , or birds in the air , excepting only that the motion of the stars is regular , and that of fish and birds is not . they who make to be as many heavens as there are planets , or that every planet hath its orb , are forced to confess , that either their heaven is fluid , or if it be solid , that there are passages and ways through which they are carried ; and to explain these appearances , they are under a necessity of feigning certain circles which they call epicicles , or excentrix ; from whence arises unexplicable confusions ; whilst others say that these circles are only imaginary . but they who affirm the sun to be immoveable in the center of the world , who conclude that the earth is in its place a seventh planet , and hath a motion round it as well as the rest , and that the firmament and the fixed stars ( which are annexed to it , and implanted in it , and seen with their orbs to wheel round over our heads ) to be like the sun , equally immoveable ; are forced to explain the motion of the planets , and find no little difficulty in explicating their appearances ; we will enquire into those which are chiefly built upon truth ; by examining first those two most famous systems of the world , i mean that of ptolomy and copernicus . chap. vi. ptolomy's system of the world examined . ptolomy and aristotle with their followers , affirm the earth to be in the centre of the world immoveable , encompassed round with air , which they think is next environed with fire ; and so in order there are orbs of the moon , mercury , venus , the sun , mars , jupiter , saturn , and of the fixed stars encompassing one the other , called the firmament : then the ninth heaven , which they call the chrystaline ; and lastly , the primum mobile , which by its incredible rapidity carries all the other heavens with it , from east to west . this opinion seems to me to be absurd , because it supposes the heavens , and especially the primum mobile , to be of an immense magnitude ; so that the earth would be but a point in respect of heaven . yet ptolomy will have these immense bodies , and vast machines to be moved round this point of earth , which seems little consonant to reason , which dictates to us , that little bodies are much more readily moved round greater , than great bodies round less ; and we commonly say when we are roasting meat , that the meat must turn round to the fire , and not the fire turn round it . it is therefore more commodious , and more consonant to reason , that the earth which is only like a point , or a gnat , should be moved round the heavens , than the heavens should turn round about it . most wisely therefore hath the creator of the universe disposed things in such a manner , that the reasons of them are conspicuous every where ; that we may say that god does not only produce works which are good in their substance ; but also that he hath done good unto all that he hath made ; that is , exactly in number , weight , and measure . besides this general reason which destroys and over-turns the opinion of ptolomy and aristotle ; we may take another from the incredible rapidity of the heavens motion about the earth ; for if their opinion be true in this hypothesis , and according to the reckoning of astrologers , we must confess that the distance of the primum mobile from the earth , is above an hundred thousand miles ; from whence may be computed the greatness of this heaven , and the manner of its motion , that it should perform and compleat its circle in the space of twenty four hours ; whereas all people agree in this ( viz. ) that the earth compleats forty miles in every hour , when in the mean time its circle is but a point in respect of the primum mobile . we must conclude therefore , that its swiftness is incomprehensible , and that every one point of its circumference , compleats each hour more than forty times an hundred thousand miles , which is incredible . to all these i add another difficulty which i have concerning this opinion , in explaining the manner , and the little hooks by which the primum mobile carries the inferiour orbs along with it from east to west ; and that the heavens and the planets go to this pole , but come back from the other , and then at last return to their first point , by the sole collibration or ballancing of the ninth heaven or chrystalline : to which if we add the solidity of the coelestial globes in that manner as ptolomy has affirmed , then neither aristotle nor tyco brache with his epicycles , and excentricities , will be able to take away these difficulties , or avoid horrible confusions ; lastly , these philosophers could not explicate the regular or irregular motion of commets , unless by appointing angels to guide them , which is ridiculous . chap. vii . copernicus's system of the world examined . this philosopher , and many other modern ones have built systems of the world after another manner ; for they place the sun in the centre , and will have the earth and the other planets to wheel round it , as we have said heretofore . this system would be sufficiently enough confirmed by refuting of that which ptolomy , aristotle , and their followers have framed ; but onely this likewise labours under its peculiar difficulties , the first of which is the experience of our senses , which seems altogether repugnant to this system , for according to this opinion , we must conclude the heavens which seem to move , as also the sun it self , to be immoveable ; and on the other hand , the earth to be in continual motion , which seems to be immoveable . but this prejudice is very uncertain , nor do our senses always so exactly and infallibly distinguish the motion of bodies , or bodies that are in motion , as experience teaches : that when any one goes on ship-board , and the ship sets sail , the shoar and the houses go away from him : for to this man the shoar seems to go away from him , though indeed he goes away from the shoar . which happens from hence , that the eye does not discern the motion of the thing which is moved , when it moves along with it ; which happens to a man at sea , who does not at all take notice of the motion of the ship which is under sail , because he himself is carried on by the same motion . to this opinion also is opposed the experience of a stone thrown up into the air , and there falling down upon the head , or before the feet of him that threw it ; for if the earth is really wheeled round and moved , while the stone is moved , it ought to fall far enough from him who threw it . for we must conclude that the earth is not turned round , and by consequence that this system of copernicus is false . to this difficulty descartes answers , that a stone must so descend , as if the earth was not in the least moved , because both from the same vortex , and by the same impression , the stone as well as the earth is carried round . to this very same difficulty gassendus answers after another manner , saying , that the stone falls before the feet of him that throws it up , because it receives two motions from the hand of the thrower , ( to wit , one horizontal , and the other perpendicular ) which since it hath received , it ought to keep also , and to describe a curve , regular , and parabolical line ; and after this manner fall down at the feet of him that threw it , if he ( viz. ) threw it up streight , and the wind not contrary to it : just as we see in a great bullet tumbled down from the top of the mast , falls streight down to the bottom of it , though the ship sails with a very violent wind. lastly , it is objected , against the doctrine of copernicus , that if the earth be moved about the sun , it would sometimes be nearer the firmament and the pole , and sometimes farther off ; and then that for that reason the fixed stars , especially the pole star , must sometimes appear bigger , sometimes lesser , which is contrary to experience . but they who defend this opinion , make answer , that the mighty distance which is betwixt the earth and the fix'd stars , is the cause why this difference is not observed . but indeed , in that manner that i shall explain the motion of the earth , this objection will appear to be of no moment . chap. viii . of the motion of the earth . copernicus attributes to the earth three motions , the first of which is called diurnal , by which the earth is moved about its axis , as a wheel , from west to east , when as the sun seems to be moved from east to west . another motion is from one pole to the other , according to the latitude of the zodiack , that is , from one tropick to another ; which motion is called annual or rather half-yearly , because the earth in six months time runs through the whole latitude of the ecliptick , and after other six months it returns to the same point from whence it had departed at the beginning of the year : so it passes through the same line twice a year , to wit , at the time of the aequinoxes . lastly , the third motion is made round the sun , whereby according to this philosopher's opinion , we are sometimes nearer the fixed stars , and sometimes farther off . there are not wanting some who attribute a fourth motion to these three , which we call a libration from east to west , and so on the contrary . but to explain all the appearances , the two first would be sufficient , were we not compelled to take in the other two likewise . the diurnal motion of the earth by which it is turned and wheeled round its axis , and which is performed from west to east in twenty four hours time , is hard enough to be explained , but here 's the comfort , that there is no less difficulty found in the opinion of aristotle and ptolomy about the explaining the motion of the heavens which ought to be performed in the space of four and twenty hours . therefore to clear up this difficulty , i suppose , if we should be compelled to have recourse to an intelligence , as a mover sent by god for this purpose : we have as much reason to assign one for the motion of the earth , as well as aristotle , to assign many for the motion of the heavens and the planets . by the same right we might have run back to the first cause and its general concourse , after the example of cartesius , who is not ashamed to call in this to help him in explaining the motion of his materia subtilis , and the vortex surrounding the earth ; as also of all other natural motions , which god , saith this philosopher , hath produced from the beginning , and always preserves without diminution , but only that this motion does transmigrate from one body into another , and as much of it as is lessened in one body , is increased in another : this is the cartesian opinion . but we are endeavouring to explain this motion of the earth by more natural reasons . i say therefore , and suppose that the sun is immoveable in the centre of the world , and yet notwithstanding , that like a wheel it turns round about its proper centre ; and this is that motion which is called circum-rotation ; and by this motion it disperses on all sides , on every part these corpuscles which produce light and heat : these corpuscles compose that great vortex which is about the sun , and which with it is carried round , and moves the earth which is plac'd in the same vortex with it ; like as a stone is moved by the motion of a rapid stream , and this same vortex carries other planets along with it , accordingly as they are more or less immerged in it . according to this explication , one may fancy the sun to be like the wheel of a clock , which moves that which is next to it another way ; for when one wheel is moved towards the right , the other which it carries with it , must of necessity be moved towards the left : so whilst the sun by its circum-rotation is moved from east to west , the earth must likewise be moved from west to east . the other motion of the earth is that which is called annual or half-yearly , and which arises from the libration of the solar body , and of the vortex which drives the earth from the part of the pole , and makes it daily go a degree farther ; and so the annual as the diurnal motion each day declines one degree onely , from a parallel , from whence arise the vicissitudes of days and seasons ; but if the earth returns by the same steps , as i may so say , it happens because the sun by its daily libration drives it on from one part ; and then after six months assuming an opposite libration , it draws it back for three months , and for the other three months which makes up six , it drives it forwards , so that the rotation and the libration of the sun makes a double or a triple motion of the earth , without the former's changing either its place or its centre . all that we have hitherto said , according to the mind of these authors , doth not as yet satisfie a spirit curious to know the truth . so here are other difficulties remaining which must be taken away by more sensible and more natural reasons . first , though we affirm the sun to be immoveable , and the earth to be wheeled round about it ; or though we affirm the contrary , there remains nevertheless , that we give an account not only of each of these motions , but also of the motions of the other planets . it is demanded what is the internal or external cause of the earths motion ? if it be answered , that the sun by its libration is the cause of it , as we have said , and as our opinion is ; it remains that we demonstrate the cause , whether internal or external , that gives the sun this motion : by means of which being librated from one side for six months , it is also librated for as many from the other side ; and by this so regular motion , it sometimes draws the earth towards it , and sometimes drives it from it , as we shall see in the following chapter , what can be said about this matter . chap. ix . of the sun the true centre , and heart of the world. the sun being placed in the centre of the world , is like the heart , inspiring life into all things , and presiding over all the works of nature whatsoever , even as the heart in an humane body is the principle of its life and all its motions ; this is that admirable machine , which without being moved out of its place , moves the spirits , humours , and all the parts , of our bodies ; in like manner , the immoveable sun by his double motion , shakes and moves the earth as well as the rest of the planets . one only difficulty remains in explaining the motion of the heart in the microcosme , and of the sun in the macrocosme : but being about to treat else-where of the earths motion , we will here only speak of the suns motion , which i call a wheeling of it round about the earth , and afterwards we will speak of its libration . elsewhere , we have said the sun to be , not only of the same nature with gold , but to be gold indeed , melted in the centre of the world , and cupellated by the fire of the fix'd stars , which are every where about it : no wonder therefore that it is wheeled round like melted gold in a crusible ; and there sparkling , and purified . that this hypothesis which will bring no little light to many things , may be better comprehended , i will bring an experiment to confirm this doctrine , which seems new indeed , but nevertheless it cannot be denied to be built upon the foundation of indubitable experience . i say therefore , that if you take gold and put it into a great crusible , with lead , copper , or other mettals ; and make a fire every where round it , these mettals will be melted together , and compose a sparkling smoaking bath ; this bath or melted matter is in perpetual motion , and so soon as the matter is made hot , it wheels round its centre without intermission . it would be much more conspicuous if this melted matter in the centre of the world were equally distant from all the points of its circumference ; for this being supposed , no man will deny , this melted matter fixed in the centre of the world , and fire being put to it every where , and on all sides , to remain in fashion as in a crusible , and to have the same motion of circum-rotation and libration which we attribute to the sun. all the obstacle we meet with at first sight consists in this ( to wit ) how this solar melted matter can remain suspended , not falling down on any part . secondly , by means of what fire it remains always melted . thirdly , how it comes to pass that since gold so soon as it is cupellated or refined , remains in the crusible in a fix'd mass , yet the sun which is like to this gold , is neither fixed , nor stands it still immediately , but being wheeled perpetually round its centre , it continues in motion , and is librated in the cupel without any intermission . to the first of these difficulties i answer , that we ought not to stand upon it , because they who place the earth in the centre of the world , do teach us , that if a great hole were made through the earth , even as far as our antipodes , and if a mill-stone were thrown into it , it would stop in the middle , which is affirmed to be the centre of the world , and there remain suspended ; for to move forwards either way would be to ascend : the same thing may be said likewife of water or other liquids which would remain suspended . if therefore the sun be in the centre of the world , why should it seem a wonder that it should remain there so suspended , since that may serve him instead of a cupel ? as to the other difficulty which belongs to the fire . i answer , that there is no want of that , because we have the fire of thefix'd stars encompassing the sun every where on all sides , and keeping this same gold in cohtinual fusion , as if it were under a great winters glove bored through every where with little holes , as we find in essaying gold. i do not say with epicurus that the fixed stars are really little holes and apertures by which the empyrial heaven which is altogether fiery , transmits its ardors ; but i affirm , that these are either little empty holes , or else filled with so many diamonds , or chrystals , through which the heat of the coelestial flames pass through ; or else that they are as it were so many carbuncles , or burning coals . this is sufficient to convince them of great ignorance , who have affirmed these coelestial fires to flow from the solar globe , and to be borrowed thence ; whereas on the contrary , they are coelestial fires and flames , which passing through this great globe of the heavens causes the gold in the cupel in the middle of the universe to be boyled and wheeled round by an equidistant and equally distributed heat . i confess as to what belongs to the third difficulty , it is very subtle , and supposes a very fair experiment : for in the course of all my curious labours , i have wondred how gold after it had a long while smoaked in the cupel , and circulated to expel in smoak all forreign bodies mixt with it , does at last stand still , and remains suddenly fix'd in the bottom , and is so condensed , that it cannot be melted again by the strongest fire , or made to circulate , unless lead be added to it either with or without some other mettal ; for by the addition of these bodies it is at the same time melted , and by the same degree of fire , and begins a new to boyl , to be librated , and to be turned round as before : and it will continue so as long as the lead or other foreign matter is in it : from whence we may conclude , that so long as the sun like melted gold is wheeled round its centre , mixt and infected with foreign corpuscles which it receives on every si de , as being placed in the centre of the world , and of the planets , which like imperfect mettals furnish it with corpuscles which are exhaled and are emancipated , and being mixed with it cause it to wheel round , and supply it with matter for motion , and so long as he returns them back in the form of smoak , like a vortex , excepting only those which are digested and turned into gold , which he reserves within himself , and does farther digest and circulate ; and when they are sufficiently subtilised and purged , although involved with grosser fumes does send them forth ; which meeting with the vortex of the earth , penetrates into the pores of it , and are changed into gold , silver , or some other mettal ; according to their greater or lesser purity , and according to the various disposition of the matrixes or beds wherein they lodge : so long i say we may conclude , that from these fumes which are sent towards the sun from imperfect bodies , are made a liquid and mercurial water , out of which , in the bowels of the earth , gold and other mettals are made . the experience which we acquire by essaying gold , ( although after a rude manner , in comparison of it with this great natural cupel ) shews us this this truth before our eyes ; for i have with pleasure tryed , that the fumes arising from the common cupels , being collected in an alembick , are condensed into a clear viscous , pulverulent , or gritty , and consequently mettalline water , whose value the curious may be able to know . i represent therefore to my self gold wheeled round in this great cupel , which is the sun it self placed in the middle of the world , and which emitting subtile fumes , receives other more gross , which it so long and so often circulates , that they being in the bosome of the earth , ( the matrix of seed , and only habitable planet ) purified and collected , do there make gold , silver , or other mettals . so the sun is the father of mettals , and especially of gold its legitimate off-spring ; whereas the others are only bastards , and being defiled in the matrix or womb , they cannot attain to the dignity of gold , unless they are free'd from their original impurity . he then that can tell how to purifie and consecrate these solar influences , which are the fumes of this admirable cupel , hath found out a great secret in nature , extreamly profitable both for health , and wealth . let me tell you an experiment which i did not see , but heard related , by the late monseigneur bezancon , a gentleman well known in paris , who professed himself an eye-witness of it . he said that when he was governour of provence , he sav'd a man's life that was unjustly condemned to dye , who in a grateful acknowledgement of it , shewed him a thing wonderful . this man , said he , took a vessel , in which put three simple things , and buried them in the earth , in a place exposed to the sun-beams , ( which are the most subtile fumes ) and having taken a concave , parabolick , or burning-glass , which he placed opposite to the place wherein the vessel was put ; the sun beams being collected and concentred , descended into the vessel in troops , in which , at length was found a very clear yellowish , and gritty water ; which being boyled in a bolt-head , was brought into a powder , and afterwards being put into a crusible with borax , turned into gold : this was performed three several times . from this experiment we must gather , whether or no the sun beams do supply water and flames serving to the production of gold , which , as i have said , is the legitimate son of the sun , and is in the earth the image of its father . but to make an end of this digression , i conclude that the sun will so long persevere in its cupel in continual motion , and circum-rotation , till these planets shall deny it vapours , for then it would receive no foreign matter , but would be throughly purged , and so would be wheeled round no more , but would remain fixed . the world it self , with its motion and circulation would be at an end , as well as all generations , which proceed from this continual circulation , by which the seminal and luminous spirits are dispersed every where throughout the world. i add another reflection concerning the sun's motion , like the motion of gold in the cupel ; to wit , that whilst the fire of the superiour stars do without intermission heat the body of the sun , foreign corpuscles through its pores enter into it , nor is it ever at quiet till they go out again ; for as much as the figures of these foreign bodies can by no mean be accommodated to the figures of the corpuscles of gold , for they drive one another backwards and forwards ( and from hence arises the equilibrium , and agitation of the atoms of gold , which is in motion ) and seeing that they cannot have a perpendicular motion , unless they forsake the rest , they are compelled to turn round like a horse in a mill , which goes on , and thinks he goes ? streight forwards , whenas he continually treads the same steps , in the same circle : but to do this , there must be a propulsion on every side ; for gold would not be turned round in the cupel , if fire were only applyed to it from beneath , and not from above , and quite round it ; which ought to be well taken notice of . we will say then that the sun cannot be moved about its own centre , that is the centre of the world ; unless at the same time it moves the ambient bodies , by the assistance of the corpuscles coming out of its globe like so many streams of light , just as we see rivers of water flowing out of the sea , and yet the sea is never the less for this effusion , no more than the sun is lessened by a continual effusion of his light ; because it receives in as much as it pours out , and these waters return back to the sea , as these corpuscles of light do to the sun , by a continual circulation . chap. x. of the moon and its changes . the moon is like an optick looking-glass , in which light and the corpuscles flowing from the sun are concentred and gathered together ; from whence for divers respects and changes they are sent towards the earth . one of the antients affirmed the moon to be a planet , very near and familiar to the earth , it is moved about the sun , because it is in the solar vortex by which it is carried round , and in it three kinds of motions are observed ( viz ) its annual , monthly , and diurnal , from these divers motions , divers aspects , in respect of the sun and it do arise , from whence are its various yet constant appearances . it s figure is round , but its mass is partly solid , partly fluid , like earth and water ; its roundness appears at full and new-moons ; without this roundness we could never see its increase or decrease . it s solidity is the cause why the light of the sun is from thence reflected to us , even as by reason of its fluidity , we observe in it obscure parts like spots , because they do not reflect the sun so much as the solid parts do ; but if in the body of the moon there are some parts higher than others , in the shape of mountains or hills , the sun beams do there produce small shadows , which are observed by the help of perspective glasses . that it cannot be half so big as the earth , is proved by optick principles , shades and paralaxes ; in respect of it self it is always in the full , because one half of it is continually illustrated by the sun : but it does not always appear full to us , but only at the time of its opposition and recession from the sun , and then also in respect of us it may be eclipsed ; because our earth at that time is directly placed between it and the sun , and by its shadow makes the moon more or less obscure , as it is nearer or farther off and as it is more or less opposite to it . these two opposite points , in which , when the moon suffers an eclipse , those great lights are found , astrologers call the dragons head , and tail. but as the earth by its interposition is the cause of the moon 's eclipse , so also by the interposition of the moon betwixt the sun and the earth , is produced an eclipse of the sun ; which is either greater , or less , according as the moon is more or less posited between us and the sun , or is nearer or farther from us . lunar eclipses can happen naturally , only in the time of full moon ; but these of the sun , in the time of new moon . an eclipse of the moon may be total and universal . but that of the sun can never , without a miracle , be so at the same time ; but this is not a real defect of light in the body of the sun , as it is in the moon , which is a dark body , and possesses only a borrowed light. we may hear what astronomical philosophers and astronomers say of it . i told you before that the sun is like melted gold , i told you likewise by the way , that the moon might be compared to melted silver ; but i think it may be truly said that its matter , as to its circumference , is more like to real silver ; but be it as it is , it continues in the manner we see it , suspended in one massie lump , a most subtile aetherial matter , full of many empty spaces , being by the creator shut up in its circumference , which hinders the moon chiefly from changing its place , and from being immerged more deeply in the sun 's vortex , whose atoms are indeed more thick and gross : by reason of its vacuities there is no fear that it should descend nearer the sun , or be able to resist the impression of its vortex , any more than the earth , which has plenty of pores , cavities , and empty spaces , without which it would too much resist the solar vortex , and would be able to get nearer its centre , that is , the sun. but its empty cavities hinder that , like air contained in a bladder , which hinders it from sinking to the bottom ; and as the hollowness of the quils of birds bear them up in the air. the moon in her daily motion finishes her course round the earth in the space of twenty four hours : or rather the earth performs its daily motion about the sun , and its own proper centre , in twenty four hours time , the moon being carried away by the same solar vortex with the earth , is daily retarded some degrees , whereupon we say it rises every day later and later , until by this resistance or retrocession in twenty nine or thirty days it hath compleated its monthly motion : and besides this retrocession it is moved by the libration of the sun from one tropick to another , and twice in every month runs through the equinoctial line ; after the same manner as the earth does it twice every year . there can be no annual motion of the moon , unless about its own proper centre . but i will wander no further about a matter meerly astrological . chap. xi . of the planets , comets , and fixed stars . saturn , jupiter , mars , venus , and mercury , are five wandring stars , called planets , of the same nature with the sun , but less pure ; whose corpuscles are sent and driven towards the body of the sun ; they are likened to divers melted mettals , and sparkling in chrystalline or adamantine cr●●bles , and the fire melting them , is that of the sun and the fixed stars . if it be asked why they are not joyned with the sun ? i answer , that they consist of a matter full of many empty spaces , and besides that , they daily disburthen themselves upon the body of the sun , and supply it with matter for depuration and resining : which the sun sends back to them more subtilised , and they distill down these seminal and mettalline spirits upon the earth . they are diversely whirled about by the solar vortex ; after which manner they obtain divers motions , as astronomers teach us . who affirm the planets mars and venus to be less than the earth , and the three others much greater ; although according to their opinion , the diameter of the earth is three thousand five hundred miles , but its circumference seven thousand miles ; including the water , which together with the earth , make up one globe . comets according to aristotle are planets or stars , produced de novo , from exhalations : by which saying , this philosopher is compelled to place all comets under the moon , which is found to be an error , by the experience of a great many comets which have appeared above the moon , and the sun too ; whither exhalations from the earth can never reach : all the time of their continuance they have a regular motion , for the explication of which , aristotle could never assign them an intelligence to guide them . seneca , the antients , and copernicus , teach that comets have been produced from the beginning of the world , and the reason why we do not see them so often as we do the planets , is because they are elevated too high above us , and since they have an excentrick motion , according to this opinion , they sometimes , and for some continnuance of time appear , that is to say then , when they descend into the heaven of the planets . but all these opinions are very uncertain . this is my opinion , that if the sun is gold melted in the cupel ( as i really believe ; ) and that from thence fumes and vapours arise ; it is no hard matter to conceive that in the solar vortex , and in the corpuscles exhaling from the sun , a great part of them are very gross , thick , and inflammable ; which taking fire , make these comets we speak of ; whose motion is regularly directed by the vortex of the sun ; yet nevertheless this does not hinder but that some comets may be generated nearer us , from terrestrial exhalation . the fixed stars are fastned to the firmament as so many little suns , they are as immoveable as the heaven in which they are included ; nevertheless like the sun they move about their centres , although this motion be neither useful , profitable , nor necessary . and so nothing compels us to say that they are actually moved . they are all said to be bigger than the earth , and to be in number ; the heaven in which they are , is said to be solid , clear , and transparent like ice ; and this is that heaven which was made in the midst of the waters , and which any one may represent to himself like a great circle of water congealed in the form of chrystal : but according to my foregoing hypotehsis , i had rather say that the fix'd stars are like so many round holes or rings , furnished with so many large diamonds or carbuncles , which serve as a medium or vehicle to the light and heat of the empyrial heaven , as we have said already . chap. xii . of meteors in the air. aristotle hath constituted two sorts of bodies , to wit , simple , and mixt ; he placeth meteors under these latter , but he calls them imperfect mixt bodies , because he did believe them not to have a substantial form , as perfect bodies have , nor to be produced by the ordinary way of generation . this doctrine is contrary to our principles ; for we say that those meteors which we see in the air , are in their kind and condition perfect bodies not differing from others , neither in respect of matter , which is one and the same to them all , nor in respect of substantial form produced in the formation of them ; for we acknowledge no such forms , but as unprofitable , and chimerical . all the difference which we take notice of betwixt them , ought to be taken upon the account of their formation and different conditions under which one and the same matter , that is to say atoms , do meet together by a disposition of their parts , by an addition of strange bodies , by an introduction of vacuities , and by a conversion of their figures . after this manner are formed clouds , which are the meteors of the middle region of the air , and which have water , air , and earth for their matter ; for from the vapours of water , and the subtile particles of earth , together with the air with which they are carried up , clouds are formed , which are sometimes so thick , that they rob us of the suns light , which happens when more of earth , than of air or water goes into their composition : on the other hand sometimes they are so subtile , that they can hardly or not at all be seen by us , which happens when air obtains the chief place in their composition : for in a word , clouds are nothing else but a congregation and mixture of corpuscles or little bodies of earth , water , and air , which are the proximate matter of them ; the vortex of the sun , the motion of the earth , and the winds , are the three concurring causes of their mixtion and elevation into the upper region of the air. other sorts of meteors are rains descending from the middle region of the air , and generated from the solution of clouds ; that is to say , when water , which hath the greatest share in their formation , freeing it self from the particles of earth , and parts of air , thence forward distill as it were by an alembick , which happens , because its particles being incrassated by the coldness of the air , the water is separated from the air , and falls down again to the place from whence it came , in the form of little drops : from this rain proceeds the earths fruitfulness , for it never descends , but it brings some portion of the little seminal bodies flowing along with it . in rains therefore is contained salt , and the balsom of the stars , which basilius valentinus speaks of , and from hence all vegetables bud and increase . the curious enquirers into nature may try whether i speak truth or no , and whether they may not find a salt as white as sugar , if they take away by distillation the unprofitable parts with which it is involved . dew is almost of the same nature with rain , only it is more pure , more subtile , and more fruitful , by reason of the seasons of the year which chiefly enjoy it , ( viz. ) at the time of the aequinoxes , when the sun and the earth are nearest to each other , which happens when the earth passes the aequator ; wherefore at that time it receives and carries along with it a greater number of solar corpuscles , depurated by his motion , than rain , or dew it self that falls at other times . dew falls down in round drops , because its corpuscles are round , and its atoms are of the same figure with the sun , whether whole or in parts . dew penetrates the earth , and moistens those places where there are seldom rains : but the sun's shining beams presently carry it away along with them into the vortex ; in the mean time , part of this salt or balsom of the stars contained in the dew , remains upon the herbs and flowers , where we observe a kind of viscousness like sugar , or honey ; thus bees gathering this dew , lade themselves with it , and make honey of it : this dew in the hot countries of palestine , aegypt , arabia , and calabria , is condensed into little grains which are called manna from this same matter sugar is made in the madera-islands , and in both the indies , where it is found inclosed in reeds . lastly , after the same manner pearls are formed and nourished in shells . he that studies to know the wonders of dew , and the vertue of the spirits it contains , may extract from thence admirable secrets for health , but for nothing else that i know of . chap. xiii . of winds , tempests , and whirl-winds . winds are the same thing in the air , as billows are in the sea , or as floods are upon land. and indeed they do sometimes disturb and move the air so violently , that the best rooted trees , and strongest built houses , are now and then pulled up by the roots , and overturned by them : and yet winds are nothing but air agitated , nor tempests , but air floods , or violent agitations of the air. some philosophers seek for the causes of these agitations of air , in the rarefaction and condensation of bodies ; and to illustrate this effect , they bring an experiment of air rarified , and going out with great force , out of a large glass bottle , and of air condensed in another phial or glass , in which the least opening being made , the external air breaks in with great force and noise ; of both which experiments , i with others have been an eye-witness . we took therefore , a great round bottle , and placed it in a cold place , and then covering it with a double skin made wet , it was placed to a gentle fire ; which by degrees being thorowly hot , and the skin prickt with a needle , the air or wind broke out from thence with so much violence , that it blew out a candle two paces distant from it , more than once . the same tryal was made with another bottle , in which pease were put , and the hole shut with the thumb , which afterwards being taken away , the air immediately with the pease , burst out with so much violence , that they like pistol bullets entred into a deal-board . a second eperiment was likewise made , a bottle was placed in a hot place , and well stopped with leather , which being brought into a cold place and the skin pierced through , the external air for half a quarter of an hours time , rushed into the bottle with so much noise and hissing , that it seemed to indanger the breaking of it . i confess these experiments have left us an idea of winds and their vehemency , but there always remains this one difficulty , ( to wit ) what should be the principle of this rarefaction and condensation of the air ; for in the first experiment , refrigerated air is shut up in the glass bottle , and dilated with heat , and then it goes violently out of the little hole that is made ; but how can cold condense , and heat rarifie and dilate this air ? lastly , what is it that presses it , and forceth it with violence to seek its exit ? and as to the second experiment , in which rarified air is condensed in the bottle ; how being rarified , can part of the glass remain empty ? and lastly , from what cause is the external air forced to break in with so much precipitation . all these things i mention , that it may be seen that these difficulties do not escape me . as to the first instance , i say that cold condenses air , in as much as it makes the vacuities dispersed through it lesser and more closely shut together ; so that there is ●uch more of matter in refrigerated air , than in the same made hot : but that this doctrine may be rightly apprehended , we must know in what heat and cold consists ; for when cold condenses the air and presses it together , it performs it by its close , solid , heavy , and plain particles , as shall be treated of elsewhere . secondly , heat rarifies air by an introduction of its corpuscles , which are almost destitute of all solidity , by which the vacuities of the air are increased , and enlarged . thirdly , the air rushes forcibly out of the bottle , because their corpuscles are compelled to dilate themselves , which they cannot do ; nay , from hence they break the glass bottle , unless a hole be made in the skin . it is true also , that the air going out of the hot bottle is altogether cold , for they are the corpuscles of cold which go out , and the noise with which they break out proceeds from the plain figures of the corpuscles of cold , which cannot pass through the litle round holes without being entangled together , and dashing one against another ; besides these corpuscles being plain , they are subtile also like little razers ; thus in the winter time we see the hands and feet of such as are tender hurt with chops and cliffs . to the second experiment i say , that the air in the bottle being rarified by the help of heat , is afterwards compressed and condensed by the help of cold , passing through the substance of the glass , and breaking of it if it be not looked after . secondly , the cold entring in , drives out or into the sides the particles of heat , and the glass on the part of its orifice remains without air , and the disseminated vacuities are gathered together into one vacuum . thirdly , the external air enters with precipitation , because it is pressed against its nature by this great cold ; and finding a place where to betake it self , it possesseth it immediately . we must here observe that rarefaction is never made on the one side , but condensation is made on the other ; and so on the contrary , and this is the first or immediate cause of winds , when the air is rarified by heat in subterraneous places , and caverns of the earth , and breaks out with violence , or when it being condensed , other supervenes with violence rushing towards it another cause of winds , or rather of tempests and storms by sea and land , are the emancipated atoms of which we have spoke already ; and which by justling one another , more agitate the air from divers parts , diversly opposite , from whence comes the reciprocal meeting and incursion of winds in the region of the air , which when they happen near the earth , they cause fearful and dangerous whirl-winds . this opinion concerning the emancipation of atoms , supposes that in the dissolution of greater bodies , the lesser particles and atoms are emancipated , and procure themselves liberty , so that enjoying their own power they run through the air , and easily and vehemently move it . these emancipated atoms in the great world are not only very much to be feared where they use greatest violence , but also in the little world , where they produce most diseases , as are horrors , fits of feavers , and their duplications , translations to the brain . diliriums or light-headedness , and phrensies : to cure which , sudorifick medicines opening the pores , and driving out those sharp-pointed atoms , are chiefly to be commended . chap. xiv . of thunder , lightning , and the thunder-bolt . thunder , lightning , and the thunder-bolt would be more stupendious , were it not that there is something on earth , from whence we learn the manner how these things are done above us . the first thing which gives us light concerning these three meteors , is the shooting off of a gun , for the thunder-bolt is represented by the bullet , the fire coming out of the muzzle represents lightning , and the report from thence holds the place of thunder . another thing which gives us a lively and more just idea of them , is aurum fulminans , which like the thunder-bolt carries its stroak downwards ; three grains of which , though never so little made hot , takes fire , and gives a greater report than two ounces of gunpowder . i will shew you its preparation in the following chapter , and give you an account of it , and i will endeavour to explain how it comes to thunder , and how the thunder-bolt falls . epicurus attributes the falling of the thunder-bolt to the apertures which the winds produce in the clouds , but the lightning he thinks arises when the thunder-bolt , by reason of its violent motion in the air , takes fire , or , saith this philosopher , the flame of the lightning is excited by the mutual meeting of clouds , which are bodies made hard by vehement cold ; or else that it is excited by the blowing of winds , or by the heat of the stars , which sets on fire the nitrous and sulphurous matter collected in the cavity of the clouds . the sound of thunder may be divers ways . first , by the revolution of a strange body contained in the thickness of the clouds , and rolled through it , as we see a solid body shut up in a pot , excites a sound and murmuring noise if the pot be moved . the same noise may likewise proceed from the breaking or bursting of the clouds , as well as it does from the bursting of a blown-bladder , or paper suddenly and forcibly extended , or the sail of a ship torn by the violence of the winds . in like manner , this sound may be caused from the mutual meeting together of hardned clouds , like that we hear , when pieces or flakes of ice dash one against another , either in the river or on the bank ; after the same manner also woods indeed stirred by the winds , the flowings of the sea interrupted , linnen and paper suspended in the air , by their violent motions excite sounds , like the sound of thunder . we may say besides , that the thunder-bolt being throughly lighted , and falling upon a moist cloud excites a great noise , such as we hear when red hot iron is thrown into water , or melted mettals into oyle , urine , honey , or the lees of wine : where we also find a certain kind of murmur , and at last we percieve so great a noise or sound , that it threatens the breaking of the vessel . but this mighty noise may be ascribed to the vehement separation of the salt , nitre , and sulphur , which being mixt together are included in the thunder-bolt , and the cloud , as gun-powder is in guns and mines . for the violent and sudden separation of nitre and sulphur forcibly seperates all bodies near them , which cannot be done without a mighty sound . therefore that we may the better comprehend the nature and wonderful effects of this meteor , i will make the following digression concerning aurum fulminans . chap. xv. of aurum fulminans , or gold imitating thunder . experience shews us upon earth a much more natural image or representation of thunder , than that which is seen in the effects of gun-powder ; and the noise and disturbance which this gold when set on fire produceth , doth so properly imitate the horrid noise of thunder ; that for this reason it is called aurum-fulminans . i will here give you its preparation , and i shall endeavour to give the reasons of its wonderful effects , and apply them to the production of thunder and lightning . take therefore ( for example ) one ounce of calcined gold , or leaf gold , or else gold dust , and put it into a bolt head , and pour to it three ounces of aqua regis , which being done , place it upon hot ashes , and the gold will dissolve , and be reduced into water ; to which pour on a sufficient quantity of fair water , and after that a few drops of oyle of tartar , for then that will cause an ebullition or boyling ; which being over , the gold will fall to the bottom , in the form of dust ; then afterwards pour off the water that swims a top by gently stooping the vessel , and dry the powder in the air , so have you aurum-fulminans , for it produceth all the effects we told you of . the reason why it so soon takes fire , is taken from the atoms or corpuscles of nitre , which are in aqua-regis , as also of the sulphur , vitriol , and sal armoniack of which it is made ; these sulphurous , and acid , and volatile salts are united together , and the precipitated particles of gold , ( for as much as the particles of the salt of tartar possess their place ) dissolve their union , and force them to give way and be separated ; so that nothing remains in the water but a dissolved salt , part of which adhering to the atoms of gold , falls to the bottom with them , as the increased weight of the powder evinces : these same particles therefore which remain in the powder , stick to the gold , so that heat penetrating this , and dilateing this matter , produces a sudden and violent separation ; hence it is that the spirits of the volatile salts being made hot , rarified , subtilised , and set on fire , the gold which before was fix'd , being accompanied with these spirits , flyes away with a thundring noise , by reason of the contrariety that is between the alcalous salt of tartar , and the acid salts , as it happens in gun-powder , where the alkali that is in the charcoal produces the same effect as is seen in this thundring gold ; excepting that the stroak of the gold and its explosion is made downwards , by reason of its fixity and weight . we see the same in the thunder-bolt , for the stroak is made downwards , the flash is seen , and the noise is heard : besides the thunder-bolt produces wonderful effects , such as are consuming of wine in the vessel , melting of the sword in the scabbard , the scabbard and the vessel being both untouched . therefore i conclude , that the stroak of thunder moves downwards , as well as aurum-fulminans ; because these terrestrial particles predominating , they fix the volatile spirits of the salts , and precipitate them downwards . the flash arises only from the rarefaction and emancipation of the solar and coelestial particles therein contained ; but the noise in aurum-fulminans , as well as in thunder , is produced by the violent separation of the more solid and more fixedly-adhering particles or atoms . but thunder consumes wine in the vessel , the vessel being unhurt , because it consists of emancipated atoms , which are therefore so subtile , that they penetrate the vessel , subtilise and rarefie the wine , and convert it into atoms , which pass through the vessel , and flye away into the air ; but in aurum-fulminans the strength of the volatile spirits not being sufficient to raise the gold on high , it is carried downwards . the principle of this wonderful effect relies upon this truth , ( to wit ) that subtile bodies are more subtilised , volatile bodies more volatile , and fix'd bodies rendredmore fix'd . for this reason , the powder of projection so called , being cast into melted mettal that is not fixed , penetrates it , and sixeth it by its own fixity : but this experience is not yet found , but is still to be found out ; so that no experience can be taken from a thing that is not equally as certain and as common as aurum-fulminans , and gun-powder ; which if there be such a powder , and it be such as they report it , it is a miracle , both of art , and nature . chap. xvi . of hail , snow , frost , &c. hail descending from the clouds , and falling down with violence , is composed of drops of water hardned by cold , and it falls down with violence , because it is expelled the clouds by a strong expression ; almost after the same manner as your smallest shot are discharged out of a musquet . snow is water congealed in the form of froth ; the slakes of it in its falling are puft up , and filled with air , which makes it very porous and light : it contains also many terrestrial particles , as appears in dissolving it , it is white , but may be made black by a sole inversion of its atoms . there are also in it many fiery particles , which warm the hands of those that long handle it . there is another kind of hail also , which falls in the spring time , it is like your smallest shot , or your seeds of coriander : this only differs from snow in the purity of its parts , or in as much as it hath more vacuities in it than there are in snow ; and on the contrary , snow has more of air and fire in it than this kind of hail , but both of them are , by the help of heat disolving their parts , reduced into water . hoary frost is air incrassated by cold , and congealed upon the boughs of trees , upon the hair of travellers , and upon the herbs of the field ; and it is called white ice : in this chrystalline whiteness a bloody redness is included , which may be extracted out of this hoary frost , and which , if it be well prepared , conduceth very much to health . chap. xvii . of the rain-bow , halo , and pareliae . the rain-bow is the most beautiful of all meteors , and the miracle of nature ; it is seen when the sun either rising or setting darts his rays upon a cloud full of little globular suspended drops of water , which by diversly breaking and reflecting the light , produce that diversity of colours which we observe in it , which ceases either by a different position of the cloud , or by the absence of the sun. this meteor appears like a beautiful arch , adorned with all manner of colours , which happens for as much as the sun looks only upon its superficies , and then when it is rising , or setting , and the clouds are either in the north , or in the south . some will have these colours of the rainbow to be only appearances , and by no means real ; but this is an error , for there is nothing hinders but that these may be equally as real as all other , though they are not so lasting . an halo is the appearance of a circle about the moon , which ariseth from a gross and thick cloud , upon which the lunar rays fall directly , so that its middle is made pervious to them , and broke through by them , though the circumference be not , which is therefore the appearing circle , and which is not as it is vulgarly imagined , nigh to the moon , but it is in the expansion of the air , and far remote from the moon . parheliae are counterfeit suns , formed in the clouds , either by the reflection or refraction of his beams , just as we see them in water , where sometimes many suns are seen , though there was never more than one . we may say likewise , that the clouds in respect of us are like those prospective looking-glasses , which represent many images of one thing placed upon a table , which one thing is only real , and all the rest imaginary : yet this does not hinder , but that these parheliae may be true lights , and suns painted without artifice . chap. xviii . of air , its substance , and quality . air is that element out of which the meteors are formed which we speak of : its substance is most subtile , and most fluid , by reason of the vacuities dispersed through it . it is nevertheless thicker and heavier in the lowest region , by reason of the mixture of corpuscles coming out of the earth and water . some think it only a mixture of the little bodies or particles of earth and water ; whereupon the quality of the air we breathe in , depends upon the climate which we inhabit : so that air is not every where alike wholsome , but very unwholesome in moorish and fenny grounds , from whence ordinarily gross and malignant vapours , thick and putrid clouds arise , which we take in when we draw our breaths . the very same air we breathe in , and which , when we take our breath , preserves our lives by its wholsome gales , is able to bring death to us , when it comes laden with sharp particles , which in their passage vellicate the lungs , and cause most vehement coughings . oftentimes also emancipated , pointed , and penetrating atoms flow in the air , which entring in at the pores of the body , disturb its whole oeconomy or frame : others ascending by the nostrils to the brain , stick to its membranes , and produce pains and convulsions , and are the causes of violent head-achs , vertigoes , and apoplexies : and there are some also which penetrating the organs of hearing , cause hummings and noises there , which continue for some time , because their particles are of a figure fit for adhesion . the air most malignant , and most to be feared , is that which is pestilent , by reason of the atoms which come out from putrid and corrupt bodies , as we have said elsewhere . the fluidness of the air does not arise from its not being compounded of solid and material atoms , but from its being rare , or loose ; and it is rare , because its parts are far distant from one another : this distance necessarily is space , this space is again either full or empty ; if empty , we have rightly concluded that there are desseminate vacuities , if full , it must be material . let there be therefore material atoms , all which mutually touch one another , and all things will be solid , and there will be nothing fluid in all nature , unless we acknowledge dispersed vacuities , from whence the rareness and fluidness of bodies arises , as shall be more fully discoursed of . the end of the second part of physick . the third part of physick . of those things which are under a man ; ( viz. ) of earth , and things terrestrial , which are called inanimate . having discoursed of those things which are , and happen above us , it is time now that we speak of those things also , which are under , or beneath us , as also of all things worth taking notice of in the earth and water , which constitute one globe , which we call terrestrial . but in this part we will consider terrestrial things only as they are inanimate , according to the common opinion . chap. i. of earth and water in general . the earth as hath been said , is a planet habitable , having three motions : the first of these is about its own proper centre , which is not the centre of the world , for the circle of the earth is excentrick : this motion is impressed upon it by the solar vortex , as a greater wheel carries a less along with it , and this is called its diurnal motion . another is about the sun , as the centre of the world , to which it is concentrical , and requires a years time to return to the same point ; and this arises likewise from the solar vortex , for the earth , being driven on by the flux of the centre of the universe , cannot be moved about its proper centre , without sensibly making an excentrick circle : and from this two-fold motion of it arises the other third , ( viz. ) from one pole to the other in the space of one six months , and returning back again in the space of six other ; which happens , because it can go no farther , nor pass the tropick , unless it recedes from the solar circle , for here it hath only the latitude of the ecliptick . for if it should recede , it must ascend too , for whatsoever recedes from the centre of the universe , in respect of that ascends , and so likewise from its proper centre . the earth in all these motions carries the water along with it , for they both make but one and the same globe , which is altogether exact and regular on the seas part , but less accurate on the earth's part , by reason of the vales and mountains . and though it be true that the earth does not seem to us to be of a round figure , yet it is proved by experience ; for that teaches us , that the last part of the ship which can be seen by those on shoar is the top of the mast , and the first things they on ship-board see as they approach their haven , are the tops of towers : from whence it may evidently appear , that the sea is as it were a belly , and eminence , which insensibly is lifted up into a convexity , that so with the earth it may constitute one entire globe . earth and water are two immediate principles of all compounds which are to be seen in this lower region of the world ; yet notwithstanding , not they , but atoms are the first elements , as it is said else-where : there is moreover a lesser number of vacuities in terrestrial than in aqueous bodies ; and this is the cause that the earth is more solid , and the water more fluid , that is to say , less solid than the earth . chap. ii. of terrestrial inanimate bodies in general . there is nothing simple , but god , an angel , the rational soul , atoms , and a vacuum . god is essentially simple in a simplicity of essence , power , and act ; for whatsoever is in him is an act , his essence is no ways compounded , nor his power idle , nor his action ever interrupted . an angel is simple in respect of essence , but his power is not always in act , nor his action ( at least the same ) without intermission . the rational soul , which is a spirit laid in pledge , or at least a physical compound with an organical body , is simple , because it hath neither integral , physical , nor contained parts ; but it self is a physical part , saving only that its powers are often idle , and its actions are changed and interrupted ; a vacuum is simple , for since it is neither a spirit , nor matter , nor any thing else but a capacity of receiving a body , and it hath an essential emptiness ; it cannot be called simple , but for as much as it cannot suffer composition by reason of its imperfection . lastly , atoms are simple , because they are indivisible , and the first elements of bodies , out of which all compound bodies are framed . i acknowledge no other elements , no other substantial material forms in bodies ; for they are not only unnecessary , but impossible : yet it doth not follow from thence , that the diversity which occurs between bodies constituting the world , and which are the compounds of the lower world , is no other than meerly accidental , and not at all essential : for , according to our principles , we determine one composition to be substantially distinguished from another , by atoms , which are the first principles of its composition , and essentially by the manner of composition , that is , by the disposition and ordination of its atoms , corpuscles , and all its parts . they who conclude that there is no physical compound without a substantial form , think matter alone with its diverse figures , and in all its dispositions , cannot possibly be the cause of the special properties which we observe in every one body , and that therefore a form distinct from matter is required to produce qualities proper to every one compound body . as for example , earth is in its nature dry , and water is cold ; which could not happen , unless earth did obtain a substantial form , which is dryness ; and water such a one as cold requires . this is that form which restores dryness to the earth , and cold to the water , when they are put out of their natural state and condition , to wit , by introducing moisture into the first , and heat into the latter . this objection how strong so ever it may seem , is nevertheless but vain ; for we say that neither the moisture of water , nor the dryness of earth are accidental qualities ; so that this ought to gravel none but those who acknowledge accidental qualities distinct from matter . ours is quite another opinion , and our language quite otherwise : for we firmly conclude , that all compound bodies which are in the world , are compounded of matter , every thing else being excluded , and that all contingent changes in them arise from matter newly added , or taken away , or changing place , or by some confused atoms or corpuscles brought thither from else-where ; or lastly , by the more notable parts changing place , or other ways disposed by the action of external agents . chap. iii. of the various qualities to be observed in compound bodies . there is a difference betwixt the qualities of simple elements which are atoms , and the qualities of bodies compounded of them ; for the first as well as atoms are immutable and incorruptible ; the others as well as the compound bodies are mutable and fleeting . for indeed propriety follows the nature of that being of which it is the propriety : so that if atoms are immutable by their solidity , the same must be said of their qualities ; but bodies compounded of many distinct parts , are forced to be changed , as often as their parts change places , or are wholly separated . that which is corrupted , as well as that which is generated de novo , is a composition ; for as corruption is a division of substance , so generation is a composition of it . to explain this opinion , there is nothing more commodious than the example of syllables , and words : for truly letters are immutable indeed , and according to their different place they vary a syllable or word without changing their figure , substance , and essence , remaining always the same , in what state or disposition soever they are placed ; and it is certain that the twenty four letters serve to the composition of all syllables , words , sayings , discourses , nay , of all the books which are composed in the world. and even as words , sayings , syllables , discourses , and books themselves are changed , the letters being still the same unvaried ; so also the greater and lesser compound bodies are changed and corrupted , the atoms being unchanged , and remaining the same ; nothing new happens to them , unless it be that they are no more the parts of one compound , but may be of a second , third , and others , successively to the end of the world. when all generations , corruptions , and motions in things of nature shall cease . letters are the true image of atoms in respect of the compositon or division of things : and as the substance , essence , and quality of words depend upon syllables , and syllables upon letters and their disposition : so after the same manner , the substance , essence , and quality of bodies , arises from corpuscles or smaller bodies , and the diversity of these from atoms and their various dispositions . from these principles may be taken away a question no less agitated , than unprofitable in the schools : ( viz. ) whether in the corruption of bodies a reduction or resolution of the compound may be made , even unto the very first matter . to this it may be answered , that this reduction is continually made , in respect of some emancipated atoms , but not in respect of all atoms , for the division is not always so general , as that all the atoms should be entirely separated , and the small number of those which flye away is scarce able to be taken notice of ; besides that , they almost all mutually adhere together , or it is seldom but they meet with others , to which they remain affixed , or with bodies into which they enter , or on which they are stayed . chap. iv. of the special qualities depending upon the composition of bodies . our doctrine rests upon two general principles , that is to say , the doctrine of atoms , and of a vacuum . atoms are the first elements of bodies , because forsooth , in their universal and radical division and solution they are reduced into them , and the division can proceed no farther . and a vacuum is necessary to the explaining the motion of bodies , and to the giving a reason of the diverse and particular qualities of every one compound body : for there are bodies thin and thick , transparent and diaphanous as air , and glass ; thick and dark as the earth ; and lastly , dry , and moist , hard , and soft , solid , and fluid . we will begin with thickness , and thinness , the parents of so great difficulties to the followers of cartesius , and aristotle : and i determine one body to be more thin than another , when it is endowed either with greater vacuities , or with a greater number of them ; so air is thinner than water , and on the other hand , water is thicker than air , because air has more and greater vacuities than water ; and this is thicker than air , because this has fewer , and lesser . they that reject a vacuum , and set up a plenitude , find themselves very much intricated , when they are compelled to say wherein the thinness and thickness of bodies consist ? for if they say that either of them is a quality , or accidental form , brought out of matter in power , or out of the power of matter , they conceive not what they say , nor can they assign the nature of these imaginary forms . but if with cartesius they say , that there is much more of the materia subtilis , or subtile matter , in thin bodies , than there is in thick and condensed bodies ; i would ask them , why this matter is more subtile and delicate than all other matter , for as much as all matter is equally gross and solid ? but then they will say , that this matter is highly rarified . yet nevertheless the same difficulty remains still , ( viz ) how it comes to be more rarified ? they will say that it arises from this , that its parts are not so much compressed , therefore they will be at a greater distance from one another : for that cause there are vacuities , and intervals : for unless they be granted , the parts are alike compressed in that , as well as in condensed matter . if they are alike compressed , than they are not more remote from one another ; and lastly , if they be not more remote from one another , they are no more rarified , and so this subtile matter will be no less gross than any other . we therefore explain the thickness and thinness of bodies in a more easie method than these philosophers , and the reason which we give of them is more clear and more natural than theirs : it is the same thing concerning clear , bright , and dark bodies ; and we say a body is more or less pellucid or transparent , as it possesses a greater or lesser number of vacuities , or as they are placed in a right or oblique line ; so air , for example , is pellucid at a certain distance , by reason of the great number of its great vacuities ; and glass is transparent , by reason of the vacuities dispersed through it , which are placed in a right line , and are very long , as they are observed to be by the help of a new microscope . the moisture and dryness of bodies arises from a mixtion of atoms , or particles either of air or water predominating : for if the aqueous particles predominate , the composition is moist ; if on the contrary , the earth is more eminent , it will be dry ; and it may be justly said , that moisture is nothing else but moist bodies , which are air and water , as they insinuate themselves into compounds , which are therefore moist by reason of their presence , and dry when they are evaporated : after the same manner as it happens to wood which hath a long time lain in the water , and becomes dry by the evaporation of that water which it was full of . a linnen cloth dipped in water , and taken out from thence , is more heavy , because its pores are filled with water , and it remains moist , and equally heavy , until the corpuscles of water are exhaled and evaporated , which suffices to make it afterwards dry and light , without the addition of two physical accidents , distinct from matter . water therefore , to speak properly , is not moist , but the moisture it self that moistens all things . from the same fountain the hardness and softness of bodies arises ; for a body is soft when it yields to the hand that touches , and the less it resists , the softer , it is , but if it hath no sensible resistance , it is fluid like air , but if it hath a little more than that , then it is liquid as water , in which if with your hand you thrust a stick , it enters and goes even to the bottom . it is otherwise in a soft body , as wax , and flesh , into which indeed one may thrust ones finger , but it finds some kind of resistance , and there are always found some compressed particles that strongly resist : all which arises from the disposition of the little bodies , atoms , and dispersed vacuities , for an atom being in its own nature solid , is resisting and impenetrable to another ; and if all things were so filled with atoms , as that there should be no vacuum , all things would be hard and impenetrable ; nor would softness , fluidness , or liquidness be found in any body , but there would be every where hardness , and an impenetrable resistency ; but a vacuum which alone does not resist , as it is more or less mixt with bodies , renders them less resisting , more soft , more liquid , and more fluid : to which may be added the figure of atoms , which is more or less fit for motion , and which admits of more or less intervals or vacuities . chap. v. of the quantity , weight , and figure of compounds . the same three properties which constitute the essence of atoms , are found likewise in compound bodies : atoms have a certain quantity or grossness , and obtain also weight and figure , but they differ only in respect of their figures . this magnitude or grossness of atoms , which we find out by reason only , is visible to the eye in compound bodies . the quantity or grossness of compound bodies arises from the addition and gathering together of atoms , and of little bodies which are thus formed of them ; which again is lessened by taking away the same atoms or little bodies . besides this general cause of greatness , magnitude , and grossness , we yet acknowledge two others , ( viz. ) an exteriour , and an interiour ; the first of these regards artificial compounds , where the artificer as an external cause encreaseth or diminisheth matter as he thinks fit : but it is otherwise in natural compounds , whose magnitude and thickness arises from the magnitude of corpuscles , and their grossness , and from the figure of the atoms determining bodies to such or such a magnitude : so that each tree , fruit , and animal obtains a natural and determinate magnitude and grossness , in respect of the magnitude and grossness of the little bodies , and the figure of the atoms contained in their seeds : hence it is that giants beget giants , nor do dwarfs ever come from tall parents : but if in either kind the individuals are unequal to their sires , it happens accidentally , by reason of hindrances caused by contrary agents , or by a defect or an excess of matter , or lastly , by an intromission of many strange bodies which in some particular individuals produce this irregularity . figure is the propriety of bodies ; which if they be artificial , the artificer is the cause of determining it according to his purpose , either by adding or taking away some particles or small bodies ; but if the compound bodies are natural , they obtain their natural figure , which depends upon the figure of atoms and corpuscles . after the same manner water is round , because all the atoms of which it is made are round . the weight of bodies arises from matter , that is , atoms ; for that body in which there are ten hundred thousand millions of atoms , is heavier than another in which there is not so great a number ; provided the vacuities are equal , or the air it self being in their pores be in an equal quantity : but if you take two bodies of the same magnitude and extension , that precisely will be more heavy wherein more atoms and lesser vacuities are found ; and consequentially the other more light . the motion of compound bodies proceeds from external agents , driving them on with a greater or lesser force ; and the easiness , or difficulty of the same motion proceeds from the figures of atoms , and of all bodies , and from the inclination which they receive from half emancipated atoms which agitate all bodies . so we see that round bodies are more easily moved upon a plain , and again , those that are pointed , more easily enter into the pores of others . but this pointed figure is sometimes occasioned by the artificer , although not altogether from his hand ; for it is confest that he cannot make an absolute perfect point out of a matter whose atoms are all of them round : from whence it appears , that the figure and position of atoms doth very much contribute to this ; but if a body naturally ends in a point , as fire does , it is because all the atoms of which it consists , are all of that figure . chap. vi. the difference between natural and artificial compounds . those who reject atoms , and are the asserters of substantial and accidental forms , imagine with themselves , that according to our opinion there cannot be an essential difference assigned between natural and artificial compound bodies ; because , say they , they both consist of the same atoms , and are alike made from them three ways . ( viz. ) by addition , detraction , and transposition ; after the same manner as it comes to pass in the composition of words , sayings , and discourses , which are made by a various addition , detraction , and transposition of letters . this is the very same example which we have brought , nor do we desire any other ; for from hence it is manifest , how from the same letters , without the addition of any thing else , words , and discourses essentially different are framed : and after the same manner , out of the same atoms nature formeth compounds essentially different ; so that there is no need at all either to admit or have recourse to either substantial or accidental forms , which are plainly useless in nature . we may here observe , and add further , that all letters are not fit to compose the name of king . by a parity of reason , all atoms are not fit to make gold ; so that all things are not made of all : but , as by the help of twenty four letters we express a great number of different and contrary things ; so , after the same manner , nature out of the same atoms composes mettalline bodies , plants , and animals ; by adding , taking away , and transposing of atoms ; yet not indifferently , but such and such atoms , of such and such a figure , for all atoms are not fit to enter into the composition of all kind of bodies . from hence is the first difference between natural and artificial compounds , i mean from this addition of atoms unknown to the artificer , yet which nature hath known rightly how to chuse ; so the artificer makes an arrow out of all sorts of wood ; but nature does not make this wood out of all kinds of atoms . secondly , artificial compounds depend upon an intelligent cause , which in its mind conceives an idea and end of its operation ; whereas the works of nature depend upon a necessary cause , which operates without any idea . thirdly , art takes perfect and compound bodies , and gathers them together , as a builder collects and gathers the materials out of which he frames a house ; whereas on the other hand , nature first divides bodies , and takes those atoms which are left after dissolution , and fits them to the work it designed ; and out of them , by the addition of some others which it meets withal , and which are in state of freedom , it produces new compound bodies . there is a difference therefore betwixt mixtion and composition , as there is betwixt the combination of gold and silver , and the generation of these mettals whether in the bowels of the earth , or in glass vessels , where ( if it be possible , ) there is a transmutation of one thing into another : for this combination does not in the least vary their nature , and they are easily separated , which does not happen in things which nature alone , helpt by art , rightly and duly composeth . chap. vii . of mettals and their formation . if those things which are above us are unknown to us , no less are those things also which are beneath us , and which happen in the shade and in the dark ; and it may be truly said that the production of mettals in the bottom of mines , is the most obscure mystery in nature ; and without any manner of trifling , to speak like a philosopher , all that can be said concerning this subject i reduce to the cause producing mettals , to the matter from whence , and the manner whereby they are produced . the principal cause , chief agent , and parent of all mettals is the sun , the planets and fixt stars concurring likewise to it : the fixt stars by their heat keep the celestial gold in fusion , and turn it round in the cupel in the centre of the world , that is the sun ; from whence issue bright fumes without ceasing , out of which proceeds light , and which carry heat , together with seminal spirits , which penetrating the pores of the earth , generate gold in the very bowels of it : so coelestial gold , that is the sun , is the parent of terrestrial gold , as it is of all other mettals , by the reflection of its light upon each planet , each of which , together with the sun , produceth its particular mettal . and the earth performs the office of a womb , which furnisheth the greatest part of the matter out of which mettals are produced , and nourisheth them afterwards : but the sun bestows seminal spirits all pure for gold , but mixed with the spirits of other planets , for other mettals . but that this generation of mettals may be rightly understood , we must call to mind that out of letters syllables are formed before words , words before speeches , out of which all discourses are compounded . nature does the same in the production of mettals , for she begins with little bodies , out of which she makes the three immediate principles of mettals , ( to wit ) salt , sulphur , and mercury . of which , salt is the grosser , sulphur the more unctuous , and mercury the more fluid and moveable part ; and out of these three , by divers preparations , digestions , sublimations , and fixations , she makes a mettalline or mineral body . but it might be said , as it seems to me , that the spirits or corpuscles flowing from the stars , purified in the sun , and received into the earth's lap , are incrassated , and brought into clear and limpid water ; which water is that viscous , sweet , and mercurial matter , which after some few ages is elaborated and digested , till at last it becomes a yellow and fixt earth , in which the spirit and seed from above resides ; which spirit makes all the corpuscles of water it meets withal like to the former , which piercing into the veins of the earth , and finding a matter that is pure , encreases the golden mine , until it meets with dead earth which hinders its propagation . but if the mixture be impure , and strange matter mingled in it , instead of gold , it only produces silver , iron , or copper , which are imperfect mettals . from this doctrine i conclude first of all , that by nature producing mettals , ought to be understood this seminal spirit consisting of corpuscles flowing from the fire of the stars , and working these miracles under the earth . secondly , that mettals enjoy a mettalline life , and after their way , a vegetative also ; that they are generated out of mettallick seed : gold out of the seed of gold. and that this mettallick embryo is nourished by the air of the stars , by the spirit and dew of the heavens ; that it grows , buds , and puts forth branches like a tree , which metallourgists call a mettalline tree , furnished with boughs , trunks , and roots , which could ne-never be , without a vital principle included in it . which things will more clearly appear , by what shall be said hereafter ; and especially in the experiment about the tree of diana . chap. viii . of gold , the king of mettals . there are seven mettals , ( viz. ) gold , silver , copper , iron , tin , lead , and quick-silver ; which chymists call , sol , luna , venus , jupiter , saturn , and mercury ; because they suppose each single planet operates upon each mettal ; which is done as i told you by a remission of coelestial spirits which are in the solar globe , and out of its vortex are carried into each planet ; who , according to the various opposition of the sun , recieve more or less of his light , and send it towards the earth , as being the womb in which pure , and impure mettals are formed , according to the purity or impurity of the subterranean lodgings . first , gold is the chief and noblest of all mettals , it is the chiefest and principal work of nature , and the heaviest of all mettals ; because the mettallick corpuscles are so firmly shut and united together in it , that very small numbers of vacuities are left in its composition ; and in respect of bulk , there is a much greater quantity of matter in gold , than in other mettals . notwithstanding this great solidity , and firmness of gold , yet nevertheless there are some small vacuities between its atoms ; for there is nothing absolutely solid and without a vacuum , but an atom in particular ; besides atoms , since they have figures , cannot be united without leaving some empty spaces ; for unless it were so , gold could not de divided , no more than an indivisible atom : there are therefore vacuities betwixt the atoms of gold , though but very small , and also betwixt its corpuscles , and lastly , between its little pieces . from this well-grounded principle , i discover the difference of the dissolutions or divisions of gold. the least and grossest of them all is that which is made by melting it with other mettals ; when therefore it is melted with some , or with the least of the seven ; it is mixed with them , and divided into infinite particles especially if it be mingl'd with a great quantity of an imperfect mettal ; as for example , if an ounce of gold be melted into ten pounds or more of lead or copper ; but the division of it is apparent from this , that not the least quantity of this mixture can be brought to the test , but some portion of gold will be found in it . another separation is made in respect of the small masses of gold , which is made by the help of aqua regis , which divides gold after that manner , that it may as in the first division be melted with any mettal ; so in this second , it becomes like the water in which it is dissolved and divided : but since it is only separated into very small masses , it is easily again reduced into a body , and to be melted with borax , and fit to become the massy gold it was before . the third division ; which is called radical , ( although it be not so ) is made by a proper dissolvent of the philosophers , which is a water clear , sweet , pure , and not at all corrosive ; fetch'd from the beams of the sun and moon ; in which gold is reduced into a clear and heavy water , and is as easily melted as ice in warm water ; and then lastly , gold cannot be said to be reduced to its first state , that is , body , unless this water be turned into earth , and this earth be made fusile , fixt , tinging , and fit to elevate inferiour things , making poor people rich , and to make that perfect which was not actually so , although it was potentially . i say this division is hardly radical , because it doth not proceed from a separation of its atoms : for gold is only brought into water , and that is sufficient ; for to bring it into atoms were to destroy it , and it would be to no purpose ; and this i think exceeds the power of all natural agents : for god only is capable of reducing gold into its first elements , and to cause it to be no longer gold , either natural , or philosophical . chap. ix . of silver , copper , and other imperfect mettals . silver is a mettal much less perfect than gold , because its atoms are endued with figures scarcely so perfect , for there are mixt with it , particles reflected from the body of the moon , nor is that mettal so heavy as gold , by reason of vacuities dispersed through it , which are both greater , and more numerous in it than in gold ; for which reason aqua-fortis dissolves it without hurting the gold. it is true indeed , that aqua-regis dissolves gold without touching silver , but that ariseth from the different disposition of vacuities in these two mettals , and because the vacuities of silver are too vast for the subtile spirit of aqua-regis , which passeth through them without division , and from the magnitude of these vacuities in silver , arises a greater sound from silver , than is given from gold. for the same cause , a greater and clearer sound arises from copper , than from silver , by reason ( to wit ) of its greater vacuities , into which , not a few bodies of air penetrate ; which by their motion produce this sound . and for the same reason that is also lighter than silver ; for as much as metallick bodies are not so strictly bound together by reason of strange corpuscles of impure sulphur mixed with them , hence it is , that copper is not so flexible or ductile as is silver . they are both of them softned in rust , because silver has too little and copper too great a quantity of sulphur ; wherefore they mutually temper each other , and the particles of each lose their acrimony . silver may be made potable as well as gold , and as potable gold is the best medicine in diseases of the heart ; so potable silver is a wonderful specifick in affects of the head. these medicines are potable , and extreamly profitable to health , when they are dissolved the third way we spoke of , and are brought into water , by a sweet water , and a friend to nature , and which the sun and moon make use of as a bath . as to copper , from it is drawn a potent and innocent sudorifick extract , performing wonders in chronick diseases . the spirits of these three , united by a fourth , make a most excellent medicine . chap. x. of lead , tin , and iron . iron is heavier than copper , because its vacuities are not so great , and besides it is burthened with much strange earth , the corpuscles of which enter into its composition : it is the only mettal hard to be melted , because of this not mettalline earth it possesseth also many corpuscles of a dry and not fusible sulphur , and very little of mercury , ( especially crude ) which melts mettals ; so that to melt it there is required a body abounding with mercury , such as is antimony : but if it be mingled with a sulphurous body , it is brought into a red yellowish saffron-colour'd calx , out of which are made the powerfullest medicines for obstructions of the hypocondria . the salt of it is sweeter than sugar , and the salt of antimony is like it ; nor is there in nature above one salt that exceeds it in vertue and eminency . these three salts are the restorers of the radical moisture . tin is a mettal abounding with much mercury , much salt , and but a little sulphur ; the salt of it is the sweetest in the world : the particles of these three substances leave many vacuities in the mettalline body , from whence ariseth its greater sound and lightness . there are three wonderful things to be observed in tin : the first of which appears in its calcination , in which we see the weight of this mettal encreased , although many vapours rise up from it ; and one would think that should much abate its gravity . this according to our opinion arises from this , that the pores of tin are opened in calcination , that the compound is inverted , and a great many atoms enter into them and fill them , and leave fewer vacuities than there were before ; and so upon that account there is more matter or weight . another that i observe , is , that the calx of tin is very hard to be melted , and indeed so very hard it is , that the wished for end cannot be obtained , unless you add a special melter : but this difficulty arises from strange and immettalick particles which have parted the body of tin , and have entred into its pores , and hinder the re-union of the parts of this mettal in melting . the third is , that tin when it is mixed with other mettals , calcines them , and hinders their refining ; and on the contrary , makes them volatile : which ariseth from the irregularity of its composition ; from its fixed salt , incapable of being melted ; from the subtilty of its atoms , and the aptitude of its figures , arising from their easily being divided . lead as it is more sweet , so it is more sociable , it purifies and refines gold and silver from all impurities and foreign mixtures : it is the heaviest of all mettals but gold and quick-silver , because there is a fewer number of vacuities dispersed through it : after the same manner , and for the same reason , in calcination it is increased as tin is , and it is easily melted , because it abounds with a crude and indigested mercury , which makes all mettals fluid and fusible : it may be separated also from its terrestrial part , and from its very sweet salt. there are many things more worthy of note which i observe in lead . the first of which is its weight , not much differing from that of gold , and arising from that , because this mettal is in a manner almost altogether quick-silver ; as also that the void intertities are filled with terrestrial and impure matter , which hinders the fixity of the quick-silver ; from whence an ill and imperfect coagulation precipitates it self ; but he that can separate this quick-silver , and digest it by an agreeable sulphur in a vessel appropriated to this work , hath found a most excellent remedy against most diseases : for the aforesaid cause this mettal is lighter than quick-silver ; and if quick-silver be poured upon leaden-bullets laid at the bottom of a pot , the bullets will ascend , and swim upon the quick-silver , as ships upon the sea. another thing that i observe , are the various colours found in lead , which are conspicuous only by an inversion of atoms , and division of bodies ; as black , white , yellow , red , and all the colours of the rain-bow . a third thing , lastly , is the salt of lead ( which the chymists call saturn , ) which powerfully refrigerates , and is of great use against the too libidinous provocations of venus , for it quite extinguisheth them . it is extracted by the help of vinegar , from whence it becomes sweet , and loseth its acrimony ; which happens only from the mixtion of the atoms , as does the milky whiteness , which upon this occasion , the vinegar is endowed with . chap. xi . of quick silver , and arbor dianae , or silver-tree . quick-silver , the last , and , to appearance the most imperfect of all mettals , because it neither endures the stroak of the hammer , nor melting , nor indeed any other tryal , is yet most perfect , because it is nearest to gold , that is , to the most perfect body ; the atoms of it are round , and in continual motion , they adhere so loosely together that they may be separated with never so little fire ; and be sublimed into a mass , of white or chrystalline powder : it degenerates likewise into poyson , by a sole inversion of it , and by being sublimed with an addition of salts . it can also be reduced into its first state , if the artist so pleaseth ; and it may be truly called protheus , every moment putting on a new shape , and receiving , and exhibiting various qualities , and colours , according to the diverse preparations which it undergoes . there are three kinds of mercury or quick-silver , there is ( to wit ) a mettalline , a mineral , and lastly , a common quick-silver ; the first of which is extracted out of mettals , the second out of minerals , and the third is the vulgar quick-silver ; which last is also of three sorts , ( viz. ) either running , or sublimated , or precipitated ; the sublimated is again , either corrosive or sweet ; it is sweet ( to wit ) when the sublimated is mingled with running quick-silver ; for if these two are a second time sublimed , the corrosive becomes sweet , because the sharp points of the sublimate are softned and blunted by the round particles of the crude mercury , which destroys the sharp and sharp-pointed atoms of the sublimate . it is therefore needless to look for physical qualities in the names of sweetness , or acrimony , since the only mutation of atoms is sufficient to make that matter sweet , which before was sharp , and sowre . this mettal is call'd mercury and quick-silver , because it is in perpetual motion ; so that it seems , as it were , to live : and to make manifest that there is in it a certain internal , and hidden principle of life , we need only examine what happens in the making of the silver-tree , or arbor dianae , whose preparation is as followeth . take one ounce of fine silver , and pour upon it in a bolt-head , three ounces of aqua fortis , and let these be left in hot ashes , till the silver be turned into water , then take nine ounces of quick-silver , divide them into three parts , and put them into three bolt-heads , or other vessels ; to which pour on first warm water to the height of four fingers , and then the solution of the silver , taking care of each of the vessels , and of the matter contain'd in them ; which afterwards let them stand all night in the window , and , in the morning , in every vessel you will see little trees , rightly distinguished with a trunk and branches . there seems here indeed a certain principle of seminal and vegetative life , since these trees are shaped after the manner of plants , although there is some difference : from whence it plainly appears , that mettals have their seeds likewise , and as well as all things else are generated out of seed . but how this comes to pass i shall not now explain , because i shall speak of it elsewhere , in the generation of plants ; where i shall give an account of their coming out of the earth , and of their growth . what is specially to be taken notice of , is , that these trees are produced in one night , which is never seen neither in fruits , nor corn. and all that can be said upon this occasion is , that from this very thing the motion of atoms , and the various disposition of corpuscles ( which by their dissolution in so little a time form these trees , ) is best of all demonstrated . these trees would without doubt bear their fruit if we knew how to water them with a water of their own kind , and to transplant them into a earth convenient for them . chap. xii . of minerals . minerals possess the next rank to mettals : the first of which is antimony , called the lead of philosophers , containing in it self an arsenical sulphur , which is poyson by reason of the subtilty of its corpuscles ; by means of which it vellicates and corrodes the inward membranes , as also produceth ulcers , after which follows a gangreen , with a corruption and division of the parts , as also of the whole body , and then death . from hence it is that the scent or fumes of antimony melting in a crusible , and drawn in by the nostrils , is deadly ; for its sharp and rough particles hurt the brain by their continual motion and agitation : yet notwithstanding the harmfulness of this fume , it conduceth not a little to correct places infected with the plague , because one venom sixeth another , and hinders its activity . gold is purified by antimony , for both being melted together , and the antimony being evaporated by the fire , the gold remains most bright and most pure ; antimony carries along with it all the foreign particles of the gold , in as much as they adhere to the atoms of antimony ; from this also is made a vomiting wine , wonderfully purging the body , yet not without some violence , by reason of its vellicating the inward membranes . the mineral that next follows , is cinnabar , compounded of mercury and sulphur , it is found in gold-mines , especially in hungary , from whence it is brought to us ; there is found in it some portion of gold , but volatile and indigested ; mercury is separated from it by distillation , in a retort , because the mercurial ▪ atoms do not closely adhere to the sulphurous ones , and this sulphur is foreign , crude , and not very well digested ; but if the seminal spirit could without hindrance have caused that the sulphur should have been by degrees separated from the mercury , and the mercury digested by a central and astral heat , nature would have produced gold out of it , but the impure sulphur hinders the action of the seminal spirit in that place where the cinnabar is found , although below , or round about it gold may be found ready made ; having branches like the branches of trees : there is an artificial cinnabar also , made of sulphur and common mercury , from these mixed and sublimed we see a most beautiful red is made , by a sole inversion of the atoms . the third mineral is emmery , or the smiris-stone , which is a marcasite found in the gold-mines of india , from whence it is brought into spain ; out of it is extracted the best and purest gold , whose corpuscles were wrapt up in the particles of a crude and unprofitable earth : the same may be said of lapis lazulus , or the azure-colour'd stone . litharge and tutty are not properly minerals , because they are not digged out of mines : for the first is only the grosser part of gold , silver , or lead : but tutty is the purer part of copper , the atoms of which , being set at liberty , ascend , and stick to the arch of the furnace wherein copper is melted . the fourth mineral is vitriol , containing in it self saline , sulphurous , and mercurial corpuscles , all of a different figure . the spirit which is distilled from it consists of atoms so acute , as that they cut thick humours , and hinder vapours from ascending to the brain : it penetrates likewise into imperfect mettals . arsenick is a white and chrystalline mineral ; there is a yellow one also called orpiment , and a third , which is red , called sandover ; all these three are very violent poisons , for the reasons above alledged . sulphur also is a mineral , easily taking fire , as being of a fiery nature ; it disolves and melts iron , just as a burning coal does wax . there is extracted from it a spirit , an oyle , or balsom performing wonders in diseases of the breast . there is also another sulphur in perfect mettals which is incombustible . chap. xiii . of salts . salt is the principle of savours , because the saline atoms have figures fit to affect and vellicate the organ of taste , that is , the tongue ▪ and pallat ; sea , or common salt is made out of sea-water , by the help of evaporation ; this very same salt is dissolved in water , a certain quantity of whose spaces it fills ; all which being filled , the salt falls to the bottom , unless something else be put into it , as nitre , or the like , which the water carries with it over and above ; from whence it appears , that the vacuities of water are not all equal , and that there are some of them which the atoms of nitre can enter into , but not the atoms of common cubical salt. common salt , vitriol , nitre , and the like , have atoms , not only sharp or pointed , but also like little hooks , adhering to glass it self , though endued with few and very small pores ; and what is wonderful , sea-salt , or vitriol , or nitre , or all of them together dissolved in water , and the water evaporated by degrees , the salt or salts we see ascend according to the heighth of the glass , to the very brims of it , whither when it is come it descends on the other side , to the very bottom of the glass , so that it is quite covered with salt. from this experiment , three things are manifest : first , that there are little cavities in glass . secondly , that salt like ivy is endowed with little hooks . and thirdly , that salt grows , and creeps up according to the heighth of the glass , just as the sap of trees , and nourishing humour ascends from the roots to the trunk , and from thence afterwards to the higher branches , as shall be said elsewhere . husbandmen experience this to be true , when they burn their stubble ; that so the rains falling upon the ashes , may carry along with them the salt which is to penetrate into the earth , from which afterwards seed , and the fruitfulness of the earth ariseth : salt does also preserve bodies from corruption , by creeping into their pores , and by that means hindring the air from entring in , which would divide and dissolve their parts , or cause a fermentation in them . there are a great many kinds of salts , ( to wit ) sowre and sweet , and acid , and bitter , and as many others as there are tastes : which ariseth only from a different disposition of their atoms . as salt is found in all things , so from them it may be extracted ; and they who extract salt out of the earth for the making of nitre , do afterwards expose that earth to the air , where it is impregnated again with salt , either from the air or rain . salts have as various motions as they have figures , which appears in the evaporation of four salts dissolved together in water ; for they do not only , after the water is evaporated , remain at the bottom , but also each of them chuseth to it self a proper place , and fastens it self to it , without mixing at all with the others , by reason of the irregularity of their figures . from the salt of urine is extracted a spirit , which mixt with spirit of wine , composeth a body hard enough , because those spirits by filling each others vacuities , are hardned ; for nothing becomes ▪ hard but in as much as its vacuities are either filled or made less . from tartar a salt is extracted , which is the salt of wine , out of which calcined , and dissolved in a cold place , is made an oyle , which being mixed with oyle of vitriol , a great boyling ariseth , and that being over , a white powder falls to the bottom , called tartar vitriolate ; for all the moisture of the tartar enters into the vacuities of the spirit of vitriol , and the salt of tartar recovers its first state , that is , of a white powder . but the strife betwixt them proceeds from the disagreeableness of their atoms , by reason of which , they very much justle one another . that salt which is called sal ▪ polychrestum , is not of less usefulness , because it drives out peccant humours extreamly well . it is compounded , that is to say , of nitre , and sulphur : d. seignette adds to it moreover another salt , and indeed i must say , that that has succeeded better than all others ; and that his sal polychrestum is a very innocent , and a most excellent remedy . chap. xiv . of subterraneous fires , and earth-quakes . there is no man can doubt , but that there are subterraneous fires , the mountains of hecla in island , aetna in sicily , and vesuvius in the kingdom of naples are invincible arguments of them ; as there are the fires of the stars above us , so there are fires below us , called subterranean , lighted beneath the earth , from the beginning of the world ; or at least , bituminous and sulphurous matters were never wanting beneath the earth , no more than coals or bituminous stones , which easily take fire , and flame . therefore the setting them on fire was not at all difficult , for there needed only one little spark arising from the striking together of two flints , or from a lamp or candle , which miners carry along with them into the pits , that so they may the better work there : the same also might happen by lightning ; or lastly , fire might be kindled of its own accord , by a fat and unctuous humidity ; after the same manner as wet hay , and such like bodies , heat and take fire . from these subterranean fires , the heat of mineral waters ariseth ; nor is there any fear that these should extinguish these fires , for bitumen burns in water , as the experiment of camphire teaches us . earth-quakes are produced by winds , that is by a troop of emancipated atoms which shake the earth ; places most obnoctious to these , are the sea-coasts , by reason of winds and tempests creeping into the bowels of the earth , through the holes made hollow by the water . but these earth-quakes arise when the earth recedes never so little from the centre of its gravity , or is interrupted in its motion about the centre of the universe , that is , about the sun ; or else , when it is driven to and fro by the solar vortex , and this is a fourth motion of it , by means of which it is sometimes nearer the sun in a streight and perpendicular line , from whence sometimes happen intolerable summer heats , or mild winters , or on the contrary , as we may have experienced . chap. xv. of waters , and their differences . there are many kinds of waters seen , which i here propose to speak a little of : the first of them is that which is called the common elementary water , whose atoms are round , and vacuities plenty , and triangular . this may be rarified , and condensed , as the corpuscles of fire entring into its vacuities , either dilate them , and remove the parts of water from one another ; or the particles of cold compress them , and shut them up by their gravity , or else expel from thence the particles of air , which had insinuated therein : sometimes water is so closely shut up by cold , that it is congealed , and brought into cones of ice , from whose lightness appears the quantity of air that has got into the pores ; and from its hardness is manifested that the vacuities of this air are very much compressed . another species of water is that , which is called destilled water , and which by the help of alembicks , is extracted out of all kinds of simples , which is thus done ; the particles of water which are in plants do free themselves , and are driven upwards in the form of vapours ; which striking against the head of the vessel are incrassated , crushed together , and condensed into little drops of water , which fall down through the beack of the alembick : after this manner rains arise and fall upon the earth ; and from hence we may learn that vapours are nothing else but water rarified , and that in nature there is a continual circulation , whilst water ascends , and descends ; it ascends in the form of vapours , and makes the clouds ; and it falls down again in rains and dew . a third sort of water is called aqua-fortis , extracted out of mettalline salts , so that , to speak properly , it is not water , but spirits , that is , the most subtile and most acute particles that are in the salts , and by force are freed from them , and which forsaking their terrestrial parts , carry only the watery parts along with them , with which they compose a sensible and fluid body . this water dissolves mettals , and brings them into a corrosive liquor : so we may see what saline corpuscles are able to do when they are freed from their earthy part , nor shall we any more wonder at the effects which proceed from serosities and salt phlegm in humane bodies : we may from hence also learn from whence the intolerable pains of the gout , gripes , and the cholick do arise ; for these are corrosive spirits freed from their earthy part , which become so sharp and penetrating , that they pierce through the parts on which they fall , pulling and tearing them asunder . the following species of water is that which is called aqua-vitae , which is nothing but the more subtile corpuscles of wine , which are of a fiery and sulphurous nature , and do very easily burn , and take fire , by the means of fermentation . an aqua-vitae is extracted out of all kinds of grain , pulse , and plants : it is a wonderful thing truly , that we see a linnen cloth dipped in aqua-vitae , and set on fire , and yet nevertheless it is not burnt , nay not so much as scorched : which proceeds from this , that in aqua-vitae there is a kind of salt , whose corpuscles sticking to the linnen , defend it from the burning heat of the flame , which applies it self to the sulphur only ; not being able to touch the salt , or the subject to which it adheres . under the fifth species of water are comprehended mineral waters , so called , because they contain in them a great many mineral spirits , as various as the places through which they pass , and as various as the mettals and minerals which they meet with in their passage : amongst them some are hot and boyling , because they run through places in which sulphur and ●itumen are heated : of these there are a great many in france , but the most natural and sweetest of them are the waters of bourbon , which conduce very much to the breast and stomach , and to the whole body , by opening their pores and vents , taking away by transpiration head-achs , rheumatisms , and pals●es ; and they might deservedly be called an universal medicine , because besides the vertues above described , they possess wonderful ones also in the stone of the kidneys , and curing fits of the mother ; unless that they too much irritate ulcers and inward apostems , as also they discover them if they lie hid . i have chymically extracted out of these waters a salt as white as snow , and altogether like to sal polychrestum ; and i can affirm that nitre also and sulphur are contained in them : for this reason , their sharp particles enrage inward ulcers , and for the same cause , sharp-pointed dock-leaves being ca 〈…〉 into the wells of bourbon , the salt hinders them from withering . after the same manner as the salt of the aqua-vitae keeps the lighted handkerchief without being hurt , as we observed before . there are also other hot waters , which instead of nitre are impregnated with vitriol ; whereupon they purge by stool much more than the others , but they are not altogether so safe . of these there are many kinds , but all the bourbon waters are alike , except the waters of jonas , which are not to be reckon'd amongst the best . moreover the waters of bourbon-lancius in b●●gundy are the hottest , and have some parts of nitre and sulphur , but the greatest part of bittumen ; wherefore they serve for bathing indeed , but not at all for drinking , because they purge only by transpiration , and plentiful sweats . there are also a great many cold mineral waters in france , and amongst the rest those of passy les paris , which besides that , they as well as other spurge by stool and urine , they have this peculiar quality , that they cure agues , and cool in burning feavers ; they open inward and inveterate apostems , they open obstructions of the liver , spleen , and bowels , by the help of the spirits or corpuscles of iron which they carry along with them out of the mines through which they pass : some of these are stronger , some sweeter , and lastly , some decayed . chap. xvi . of the sea , its ebbing , and flowing , as also of the saltness of sea-water . the sea goes about the earth like a circle or girdle , and the earth is like an island in the midst of it : but if by the author of nature cavities had not been digged in it , in which the sea might be placed , it would overflow the whole earth . the first thing in the sea that offers it self of note , is the saltness of its waters , originally produced from saline massy bodies , produced at the beginning in the earth , and melted by the help of the waters , which from thence as now they are , were impregnated with saltness . the heat of the sun does not a little contribute to th●● saltness , consuming its humidity and phlegm , as do also the salt which rivers and floods wash out of the earth in their passage thither : from whence it appears , that it may be truly said , that all the salt which is contained in the earth , is carried into the sea , and drawn out of the earth by the help of rivers , and waters derived from them , and running through the earth , whilst they are filtred to constitute fountains of fresh water . now if we could filter sea-water after this manner , there would never be any scarcity of fresh-water in ships , and long voyages . another thing that i observe in the sea , is the ebbing and flowing of its waters , in some places so very remarkable , and regular in their turns every six hours . there are some who have thought that rivers entring into the sea on one part are the cause of its flowing , but falling into it from another part , are the causes of its ebbing . others have attributed this effect to winds , but the greatest part to the motion of the moon , and to the condensation and rarefaction of the lunar air. this is the opinion of antonius à reita , extant in his book entituled oculus enoch & eliae , where he supposes that rarified air presses the sea , and lifts it up on both sides like mountains , from whence there ariseth its flowing : which air being afterwards condensed , the sea begins to subside , and the waters to return to their first state , that is , they ebb. he endeavours to build this opinion , by this argument , ( to wit ) that this motion is most observable at the full of the moon , at which time the air is very much rarified , and at the new of the moon when it is very much condensed . for my part i would rather say that the ebbing and flowing of the sea ariseth from the earths motion from one tropick to the other : for it cannot possibly in its diurnal motion move a degree forwards daily as it doth , without driving the waters from one part , and attracting them from the other . according to this opinion a reason may be given why its ebbing and flowing is only from south to north , and from north to south , and that they are lesser between the tropicks : besides , there is nothing contained in this opinion which is not very probable . but if there are some irregularities observed in ebbing and flowing , they arise from islands , rocks , straights , or promo 〈…〉 tories , which very much hasten , retard , or lessen this motion ; and partly upon this account , that is to say , by reason of the straights of gibralter , there is no notable ebbing and flowing in the mediterranean sea ; besides it is seated between the two tropicks , and is neither too much northerly , nor too much southerly . chap. xvii . of springs and rivers . there are two kinds of springs , ( viz. ) those that sometimes run , and those that run always ; the first proceed from rains , but these arise from the sea : but to speak properly , the sea is the source of all springs , and fountains ; for rains arise from vapours raised out of the sea by the help of the sun , and then falling down by drops , out of which arise the first sort of springs , which are not perpetual . but perpetual springs are derived from it more immediately , by the help of some subterraneous watery store-houses which are filled by aqueducts proceeding from the sea. it is commonly asked why sea-water is salt , and yet spring-water which comes from it is sweet ? to which difficulty it is answered , the aqueducts rising out of the sea run through subterraneous sands , by which the water in its passage 〈◊〉 filtred , and deposits its salt , or else the salt is precipitated and falls to the bottom of these subterraneous watery store-houses , as we see in salt-pits , or after the mixing of oyl of tartar and spirits of vitriol ; or that the atoms pass through imperceptible aqueducts through which the saline atoms cannot pass , by reason of their square figures : so water is made fresh by the help of straining : or lastly , by the means of distillation . so water being raised up in vapours , and then condensed , distils into other receptacles which recieve it , and send it to others , till it comes to the place where the spring breaks out . it seems a wonder , that springs arising out of the sea should be able to ascend to the tops of mountains . to which difficulty it may be answered , that the water of the sea is equally as high as the highest mountain , because the earth and water make but one globe , and the mountains of the earth do appear to us to be high and lofty , only in regard of the plains and vallies in which we are placed , and from whence we look upon them : but the sea is higher than the plains and vallies , if you conceive it all universally , because it makes a perfect circle : and if a line should be drawn encompassing the whole terraqueous globe , it would be found a perfect circle , without any irregularity . from this supposed principle it is evident , that sea-water does not ascend , that it may find an exit out of the tops of mountains , but that going out of them it descends , and produces rivers in the middle of plains , and bottom of vallies . and this they ought to mind , who have said that water ascends out of the sea to our mountains , three ways , by which it is wont to be raised ; ( to wit ) by the means of pumps , pipes , or woollen cloth ; so they say sea-water may be drawn up to the heighth of mountains , by help of the beams of the sun , and stars ; or by channels or pores unknown to us , and made in the shape of pipes , and disposed of after the manner as we see all the wine in the vessel taken out from thence by the help of a pipe ; or lastly , sea water may insinuate it self into a spongy and light earth , which imbibes it , and causeth it to ascend and flow ; after the same manner as we see all the water contained in a bason , to ascend to the brims of it , and by degrees to go beyond , by the help of cotten , or a little woollen cloth : as pleasant and as subtile soever as this fancy may be , i think my opinion is better grounded , and more agreeable to truth . by what hath been said , it is apparent hitherto , that sea-water supplies matter to springs and fountains ; these do supply matter to rivulets , and rivulets to streams and rivers , which empty themselves into the sea ; from whence they come out to moisten the earth , and that , as i said before , by a continual fluid circulation . it may be lastly asked , what may be the cause of this circulation , and from whence proceeds that force , with which we see floods and rivers to run downwards ? for to say that water will seek after its proper centre , is to flye back again to an occult cause , and to renounce our principles . i conclude therefore , that the atoms , corpuscles , and drops of water are of a perfect round figure , and since they have a certain inclination without hindrance nothing can keep them back , but that without interruption they do and will drive one another forward even to the world's end. the fourth part of physick . of those things which are in man , and of man himself , as he is a compound , physical , animated body . we are now come at length to our fourth and last part of physick , wherein according to what we proposed , we are to speak of the things which are in man , whom now we consider as a body animated : which compels us to speak of the soul , and of life in general , and afterwards descending to special , we will explain the life of man as he is rational , and we shall endeavour by natural reasons to prove the immortality of his soul. chap. i. of life in general . life , as we have said elsewhere , appears only by action and motion : so those beings which have most of action and motion , obtain also most of life : and we say a man is dying , when there is but little motion left in him , and dead , when it is quite abolished . every motion is not a vital motion , for that it may be so , it must be internal of the thing that acts , and proceed from a principle that is not external : wherefore the motion of a stone that is thrown into the air , is not a vital motion , because it comes from an external cause ; ( to wit ) from the hand of him that throws it . i say further , that it must be the motion of a compound body , if it be a vital motion ; and for this cause , the motion of atoms is not so , because they are simple and indivisible beings , neither capable of life nor death . and for as much as atoms are not compounds , tho' they compound bodies ; so they are not said to live in the least , although without their impression and ministery there is no life , nor no motion in the bodies we speak of . life therefore is an action and motion of a compound and organical body arising from an internal and seminal principle : and in this sense mettals may be said to possess a certain kind of life , since they obtain a certain motion of vegetation , by which they grow : and we may determine this motion to arise from an internal and seminal principle , though it be abstruse enough , and the organs of life scarcely appear ; so that it is a very difficult matter to distinguish them in plants , and in some animals , as in the fish called a muscle , and in oysters , which are nevertheless endowed with a more perfect life than mettals and plants . we shall in the following discourse tell you wherein this life consists , and how mettals and plants dye as well as other living creatures . there is a great difference between life and the principle of it , tho' not in like manner between life and motion , or vital action . for life is the action and motion of divers beings gathered by nature together , and united after such a manner , as that the parts of it move one another , as we see in machines ; and what the pullies and springs are in these , the same are the spirits in natural compound bodies , that is , the most swiftly moving atoms . from this doctrine is collected , first of all , that there are atoms more swift , and fuller of motion than others , by reason of their subtilty and figure , such as are coelestial , fiery , and luminous atoms , to wit , such as heaven , the stars , fire , heat , and light are compounded of : this we judge by the compound bodies that are made and framed out of them : for humane spirits instructed with material senses , is not able to penetrate into the essence of atoms , and their special difference . but we determine that the atoms out of which heaven , the stars , and light are made , have figures , and activities greater , more perfect , and more fit for motion , than those that compound cold and heavy bodies , although ( when the thing is well considered ) it may arise from their greater liberty , and more perfect figure . secondly , according to our principles , we must say , that the vital spirts so called , are nothing else but a certain number of atoms free from all composition , and such whose figure and condition renders them unfit for service and slavery : this doctrine supposeth that there are two sorts of atoms in nature , some of which like common-people are destined to imprisonment , service , and bonds ; but others , like nobles to liberty , and command over others : now those whose lot it is to be like the commons , are made to compose the machines of our bodies , and they are such as entangle one another , and are linked and bound together in the formation of bodies ; whereas those which cannot be bound nor undergo slavery , are destined to move the whole machine of our bodies , as not being fastned to any part , but running through all parts , and bestowing every where motion , sense , and disposition : these are what are called vital spirits , because they bestow life , that is , motion : these atoms therefore are not life , but the principles and authors of it . sometimes atoms that compound bodies get out of service , and as often as occasion offers , and bodies ●uffer division , are emancipated ; for in all separations and corruptions of bodies some atoms do flye away , and like the first seek to recover liberty ; and when it happens that these fugitive atoms are mingled together with those that are essentially free , from thence arise conflicts in our bodies , and from these , ill dispositions and our diseases , which there is no help to be hoped for , nor any cure , unless these rebellious and emancipated atoms are restored to their first confinement , or else driven out of the body , that so by this means the spirits may remain pure and altogether free in their motion , and not be interrupted by these irregular atoms which are the common disturbers of nature and health . and for as much as some atoms continually flye out of those bodies which we use for nourishment , by reason of divers degrees of corruption which they are forced to undergo before they can be changed into our substance : so it is certain that there is always in us some principle of a disease to be found , and that we never in this world enjoy a perfect health , and that those are only most healthy who are less sickly than others : as i have said elsewhere , that there are no men absolutely wise , but that they that are called wise , are less ignorant than others . but moreover , if captive atoms are sometimes free'd by emancipation , so on the other hand , those which are not used to be detained , are sometimes incarcerated , and involved with others , nor can they stir beyond the limits of their prison : and there are some which in like manner are so included with others by the providence of the creator , and necessity of nature , and some only by accident , and the power and plenty of matter encompassing them . so the atoms shut up in the heart , that they may give motion to it , and to the whole body , were incarcerated at the beginning of its formation , or rather being cast into seminal bands when god created it ; afterwards they are translated out of this first prison where they had little or no motion , into another , where they enjoy a more free and wandring motion , as shall be more fully discoursed of in the following chapters . the third thing that flows from this principle , is , that these same atoms are the cause of motion and life , and that there is more of action , and more of life , where these are in greater plenty and number ; provided the corporeal machine be disposed to motion : for one of the principal springs being broke , the vital atoms lose their action , the greatest part of them exhale and withdraw themselves , and others wandring about , continue vagabonds without any order or method . so that it is necessary that the parts of a compound body should be disposed in some order , which when wanting , the vital atoms exert no motion ; but this order of parts would be to no purpose , unless the vital atoms were present to give them motion : the same thing we observe in a clock , where an integrity and just disposition of the wheels are required , together with the force of a spring to set all the wheels in motion . although there be a great proportion and likeness between living natural bodies , and these artificial machines , yet nevertheless there is a great difference between them , for atoms are natural springs , and exist originally in the seed out of which the body is produced , and they themselves are the artificers of the machines which give encrease to it , and dispose the parts of it in such manner , that they may there exercise their motions , and this is that great artifice of nature , which operates by seeds produced from god , which exceeds all that ever art can devise . chap. ii. of the differences of lives . the difference of lives are only known by the difference of vital actions , of which there are four kinds , ( to wit ) the mettallick , vegetative , sensitive , and rational . man the little world , enjoys a life , under which all others are comprehended , and chiefly in him we observe a vegetative life , as in plants , and a sensitive as in brutes ; besides which two kinds of life , he possesseth a third of his own , which is a rational life ; he is nourished , that is , and grows like plants , he is begotten of another , he is sensible as an animal , and he speaketh and reasoneth as a man ; all these different operations which we see in man , perswades us to consider him especially , and to begin with the life of plants , which seems less considerable than the sensitive and rational , and which comprehends under it , their generation , growth , and nourishing , which three are equally conspicuous in man as in plants , though in a more noble and more eminent manner . chap. iii. of the vegetative life , common to man and plants . the life of plants appears from their growth which supposeth nutrition , and both these suppose a birth , and this implies a generation : for whatsoever grows in a vital manner , and by nature is nourished ; so likewise whatsoever is nourished , hath a birth , and every thing that is born , is begotten . we will therefore begin to speak of man's generation , and of the first forming of him . the generation we here speak of , is the production of a thing out of seed , under this generation are comprehended . conception and birth , as separation and death are included in the corruption of things . this is that which is not found in the works of nature , whose conception is made in the mind of the artificer , and its formation depends upon his hand , but all that is external to the work , which may be afterwards broken and divided ; when in the mean time it cannot be said that we take away life from it , or bring death upon it . so that whatsoever is begotten , to speak properly , lives , and whatsoever lives is produced out of seed : now seeds are created from the beginning , and by the author of nature ingrafted into every plant , and kind of tree bearing fruitful seed : so we see that there is a perpetual propagation and encrease of individuals in every species in the earth , as well as in the waters and in the air. all and the only difficulty remains in explaining the nature of this seed , and the manner of its propagation . these two are mysteries in nature , which seem to surpass all humane reason : nevertheless i will give you my meditations of them . and first of all , i suppose we may consider seed in general , and as it is to be found , as we have said , in mettals , plants , animals , and man. for after this manner being looked upon in general , it is nothing else but a medium disposed by god to the propagation of these four several kinds in the world , so that one substance as to its kind produces its like in the same kind ; as mettal is produced from mettal , and a plant from another plant , &c. from whence appears the fanciful folly of chymists , who strive to multiply mettals without a mettallick seed , and to produce gold without its peculiar seed : for the same thing that in general seed , is in respect of the four named generals ; the same in special , is seed in respect of the individuals which are produced of it . for indeed to produce plants , the seed is only to be sought for in the vegetable kingdom : so in like manner to produce corn seed is required , that is , a grain of corn ; to produce an apple , there is need of the kernel of an apple , or at least a sien of it , which contains in it part of the spirits and seminal corpuscles , which insinuate themselves into the wild stock of the tree in which they are ingraffed or inoculated , and produce the same effect that a grain does which is thrown into earth fit to receive it . this is that vegetative seed which we here speak of ; and in this regard we consider man , as he is partaker of the life of this species , and begotten out of seed . nevertheless we are to distinguish the two substances in man ; ( viz. ) the material part , which is his body ; and his spiritual part , which is his soul , created by god , whereas the other is begotten . so that we here speak of man onely , as he is a material compound , without medling with his soul which is immortal . these things being supposed , i turn me to the two difficulties , which i have obliged my self to explain , and i design them a peculiar chapter . chap iv. of the nature of seeds , and of their propagation . the learned fernelius affirms that seeds contain an astral and coelestial spirit , but galen , that they contain something divine . these great wits have spoken most wisely , and have considered the seminal spirit as a thing surpassing the capacity of our spirits ; but what is much tobe lamented , they have left us in admiration , and ignorance . therefore i try as well as i can to resolve these difficulties , that i may perform my promise . first of all , therefore , since matter is every where one and the same , nor does the astral and coelestial differ from the terrestrial , as we have said elsewhere , but only in this , that atoms which make coelestial bodies , have figures different from them which compose terrestrial bodies , and that the particles of those are better and more strictly united than these : i say we must not conclude with fernelius , that the elements of the stars are different from the elements of the sublunary world ; nor with galen , that that divine thing in the seed , is a certain part of divinity : but we must confess , that seeds are bodies composed of many parts , not only in respect of the sperm and diverse coverings in which the seminal spirit is shut up and kept , but also in respect of the seminal spirit it self , which is not a simple thing , but a body compounded of most subtile atoms , excellently figured , made , and proportioned , that as an original they may serve to the forming all copies afterwards in the propagation of the species . these are the atoms , as i said , shut up , yet without bonds or servitude . this doctrine is agreeable to our principles , and as we have compared atoms with the first elements of grammar , which are letters ; we say likewise , according to this opinion , that letters may be made and written so exactly , as to serve as a pattern to make others by : in like manner , among atoms there are some so well made and formed , and disposed in so just an order , that they may serve for samples and patterns to others ; and in this manner i conceive of seeds . i come now to the next difficulty , which represents the multiplication of every individual , by a sole dilatation of seeds : but the manner how this dilatation is made , is not easie to be explained ; but i apprehend it after this manner . a grain of corn , which is a seed , is thrown into the earth , where it putrifies , and is dissolved by an acid menstruum which contains in it a spirit , whose atoms are partly of the same nature with the spirits of the seed , or at least are subtile enough to penetrate into the vacuities of the husk of the grain , and sperm in which the seminal spirit is shut up , which spirit ( the coverings of it being dilated by these apertures ) frees it self from the prison wherein it was detained , and the atoms and original corpuscles begin to drive on one another , they being themselves driven on by the atoms of the acid or dissolving spirit , which acted the first part in the play , and received its motion from the others : for whatsoever is moved , is moved by another , and so successively the parts of the world , particles , corpuscles , and atoms mutually drive on one another , and this motion began with the world and will continue 'till the end of it , when god will fix all things , and put a stop to all generations . so that these seminal spirits being thus loosed , and endowed with liberty by the acid spirits , are still driven on by them , and being pressed , rise upwards , and form a stalk with a very slender top , by the concourse of the salt of the manure , and out of the corruption and division of dissolved atoms of the neighbouring bodies which they luckily meet withal , or which are thrown into the earth near that place on purpose ; this is what husbandmen know very well , who for this reason dung their grounds , and burn the stubble . but if they knew how to steep their grains , or seeth corn in an acid dissolvent ; or water their grounds with it , there would be none found so barren , but would become fruitful , nor would the husbandman be a little pleased with his plenty of corn , and from thence the truth of our principles and experiments would be manifested . man , who is generated out of humane seed , and like plants receives his first formation , does in this case very much excel them . for as in his dignity he excels all things that have material life , so also he is begotten and conceived after a more noble and more eminent manner ; and we may say with plato , that a man of all wonders is the most wonderful , not only in his perfect being , but also in his first formation . this formation is indeed a miracle of nature ; which cannot be more naturally explained , than by saying , that the womans womb after having received the man's seed , is shut up by the contraction of its fibres , and the seminal body , finding there an acid juice , putrifies and is corrupted , in the space of eight or ten days : the seminal spirit thus extricating it self , and joyning with the blood that is there , and even now at the beginning being joyned to the womans seed , out of two is made one , partaking in the conception of father and mother , which is then afterwards formed by the help of this acid blood which dissolves it , and is the cause why these two seminal spirits are joyned together , and out of two , compound one only being , which is called embryo . the whole wonder consists in this ordination of parts , which are disposed in so elegant an order , that there is no man in the world able to give them so just an order and disposition ; and now , behold what i think of this business . besides the general providence of god , which i acknowledge in all things , and besides that particular one , which he takes care of man as of his own image , i cannot but return to the motion of spirits or seminal corpuscles which form a body fit to undergo their operations . as many as proceed from every one part of the body generating , produce a part in the body generated ; and form it like themselves : the corpuscles or seminal spirits derived from the eyes , form eyes , and we may say the same of the other parts of the body ; this supposes seed to proceed from all parts of the body , and from hence we gather , that their parts who exceed measure in the venerial act , are all weakned , especially the brain , which is sometimes so shaken together , that it heavily decays , and the powers of it are dissolved : so that these sort of men often dye , seized with epileptick convulsions , palsies , tremblings of the nerves , arthritick pains and defluxions . it remains therefore to know how the parts of the eyes form the eyes , the parts of the brain the brain , and the parts derived from the hands and arms , the hands and arms of an embryo : for we see that the blind beget blind , and the lame the lame , unless the mothers blood supplies this defect . i say therefore that in the resolution or dissolving of the seminal body , there is necessarily caused a motion of corpuscles mutually driving one another to and fro , each possessing that place which gives them its figure , by which they are detained in a due site , nor can they abide elsewhere . so the corpuscles which form the eyes , are of that figure that they cannot be placed elsewhere , without a violent concussion of these mutually self impelling atoms , and these concussions are sometimes the cause why when the women are hurt , the child is not at all formed , and that by reason of the sole inordinate motion of one corpuscle , which either does not , or being hindred by others which cause this motion , cannot find a place due to its figure . it is plain therefore that seminal corpuscles have the figure of that part from whence they are derived , and the whole humane body is no otherwise shut up in a small part of matter , than an whole oak in an acorn , and an apple in a kernel . the example brought by me above concerning the divers kinds of salt dissolved in water , which in evaporating part asunder from each other , and each possesseth his place , not without a difference of figures , will give some light to this my doctrine . chap. v. of nutrition , which plants and brute beasts have , common with man. nutrition is a vital action , and so proper to living creatures , that as there is nothing nourished that is not living , so there is no living thing that is not nourished . all the difficulty lies in the manner of nutrition , for no man doubts but animals and plants at the beginning of their existence are nourished , and grow , which could not be , without the addition of new matter , which is changed into the substance of the thing living . this addition of matter takes in , its attraction , preparation , digestion , and its distribution through all the parts of the body nourished . these opperations appear in plants , wherein it is amiss to attribute that to nutritive , attractive , digestive , and distributive qualities , which may be explicated by the motion of the atoms or seminal corpuscles contained in the seed . but because nutrition is much more conspicuous in living creatures , and especially in man , it will be necessary to explain the reason how that is performed in him in the first state after conception ; and afterwards , when the organs are formed : for there is need of aliment , that the organs which are just formed , and tenderer then , to be sufficient to undergo their operations , may grow and be encreased . so that at the very moment he begins to live , there is a necessity that he should be nourished . chap. vi. how and with what aliment an embryo is nourished 'till the time of his birth . the first thing that is done after the laying together of the parts of the embryo , and the disposition of its organs , is , the infusion of the rational soul , which god in one and the same moment creates , and gives to this little body as its lodging , forty , or sometimes more days after its conception : what is done before the infusion of this soul , to speak properly , is nothing else but a disposition of the organs to receive it . this admirable structure begins from the heart , head , bones , and other particular fundamentals ; and when it is already compleated , and the soul infused , the seminal atoms presidents of the formation of the body , persevere in performing their works , taking as companions of their office these particles of the mothers blood which may serve to nourish the infant , being sensibly solicitous for its increase , 'till the time of its nativity . yet nevertheless it is very difficult throughly to declare the true reason of the nutrition and life of the infant for seven or eight months together . gassendus recounts three opinions of the antients concerning this thing , the first is of alcmaeon in plutarch , affirming the infant to be nourished by all parts of the body , drawing in by the help of the pores a necessary aliment . the second opinion is by the same plutarch attributed to democritus , this philosopher teaches , that the infant is nourished in the mothers womb , in the same manner as it is nourished when born , to wit , by the mouth , and this is the cause he says why the newly born seek the breast with open mouth . the third is aristotle's , galen's , and many others , who conclude that the infant takes no nourishment in the womb but by the umbilical veins , which taking their original from the bottom of the matrix , insinuate themselves into the middle of the abdomen or belly , where being collected into one trunk , they lead on the mothers blood into the hollow part of the liver , where part of it is carried into a branch of vena-cava , and part into a branch of the vena-porta , and the two arteries which accompany the umbilical veins , having passed the liver , each of them apart go to the two branches of the aorta or great artery , and carry the arterial blood which they bring thither , that it may all be distributed through the whole body of the infant , and changed into a substance fit for its nutrition . this opinion is confirmed by the refutation of the two former . for the first is false : for if the infant was like a sponge , it would not be nourished , but swelled , by the water or serous humour in which it swims , and which is contained in the amnion . the second opinion is not probable : for the infants head is placed betwixt both knees , nor can it suck the caruncles , which are covered with a skin , as is supposed , unless at one and the same time it should attract the water wherein it lies hid , or penetrate the membrane in which it is involved . the third opinion standing firm , which i believe rests upon a better foundation , nor does the infants stomach generate chyle , nor its liver blood , the mothers blood subministring all those things : and from hence it is , that a woman with child communicates to the fruit of her womb the purity or impurity of her blood , her good or ill nourishment , as also her health and diseases ; and these diseases are hereditary , not but that there are some which proceed from the fathers , whose impure blood , licentious living , ill nourishment , and frequent excesses afford matter to these evils . besides , we may say , that the infant in the mothers womb does neither live nor breath , but by the mouth , heart , and lungs of the mother ; from whence it comes to pass that the infant for the most part follows the mothers affections and inclinations ; and seeing that in the state wherein it is in the womb , it is tyed to its mother in so strict a bond of union , it is impossible that she alone should be feaverish , nor that the big-bellied woman should dye , the child remaining alive and healthful . chap. vii . how man is nourished after he is born. aman born hath need of nourishment : now nothing can nourish him which hath not some spirit of life : so roots , plants , corn , pulse , flesh , serve to the nourishing of a man , and all this business is performed by the benefit of atoms and vital corpuscles passing from one compound body to another . this nutrition is necessary to encrease the substance of the born infant , and so there is need of a new compound body to serve it for aliment : and this compound body must of necessity perish and be destroyed , that so it may nourish the other compound body that is to be produced . such a compound body is milk , being blood made white , and fit to nourish the infant ; and the same blood wherewith the infant was nourished in the womb , being brought by the epigastrick veins to the mammillary's , is there prepared , and by a sole inversion of the atoms , or a different combination of the corpuscles , this blood is turned into milk , which by the childs sucking being drawn into its mouth , is received into the stomach where the first digestion is perfected , and without any other mystery , the chyle becomes milk by the sole inversion of atoms , their site being changed : moreover , this chyle brought by the branches of the vena-porta ( according to the antients opinion ) to the hollow part of the liver , is converted into blood , and becomes what it was just before ; this demonstrates the circulation of compound bodies , which are turned from one thing into another , the first elements of things always remaining in their own nature in such a number of mutations . blood being in this manner prepared in the liver , is carried from the greater vessels into the lesser , and out of theseit distils like dew into the parts of the body , and is there converted into a substance homogeneal to the parts that are nourished , and by this addition of substance the body is nourished , and encreaseth . this addition differs much from that , by which stones take their encrease ; for this accretion proceeds rather from an external agent , than from an internal principle , and is almost totally performed in the superficies ; whereas in living bodies , animals , and man especially , it is done by internal agents which make part of the compound , and universally extend themselves into all the inward parts which are nourished . we must constitute also another kind of difference between the reason why plants and animals are encreased , and the manner how stones and mettals themselves take their increase . and in animals indeed , three divers states are to be considered . the first is of augmentation , in which an animal by nutrition acquires more of substance than is dissipated , which happens in a man from the time of his nativity to the age of two and twenty . the second is a state of consistence , where the animal by aliments acquires so much substance as it loses in taking pains , which happens to a man from two and twenty to forty four . the third is of decrease , wherein a man loses and dissipates , more substance than he acquires by aliment , and this happens to a man from forty four to the sixty eighth year , and longer . aliment therefore is the support of nature , without which it could not make up the losses which we suffer by the evaporation of the more subtile parts , or by a consumption of the moist , or by an alteration , loss , and ablation of the solid parts : but besides that , this very thing discovers that continual loss which the substance of living bodies makes , by reason of the opposite motions of atoms which mutually drive one another to and fro , some reciprocally moving others , and the more fixed those that are less fixed : it does also constitute a difference between this , and the life of mettals , which doubtlesly increase inwardly , and outwardly , by reason of an internal and external principle , and new addition of substance : but some contingent loss or dissipation is not repaired by this addition , which we may see in plants , and more distinctly in animals . the life of animals , which in some things they have common with plants , doth yet differ from it in many circumstances , which do not occur in plants , for plants have neither bones nor teeth to take and chew their meat , but they take their aliment by sucking , without chewing , by which very thing the first digestion and resolution of aliments is performed . hunger and thirst precede this chewing , which does not appear in plants . hunger is the desire of a solid , and thirst of a moist body . sharp-pointed atoms move hunger , and the corpuscles of the acid liquor which velicates the tunicles of the stomach . thirst hath its beginning from the drying up of this acid liquor , its moisture being consumed by the heat of the liver , or by violent labour , by reason of this dryness the orifice of the stomach wrincles it self up , and the parts of the jaws , palate , and tongue perceive pain and pricking ; to which it requires no other remedy but liquor , when the atoms fill the wrincles and tissures proceeding from the evaporations of the humid parts . chap. viii . the sensitive life in man , and other animals . man would not be in the number of animals , if he did not enjoy a life of sense as well as other animals , but he is an intelligent and rationable animal , and by a special priviledge bears the image of his author . he possesseth a spiritual and immortal soul , than which there is no other substantial form in the world , and consequentially , only man is compounded of matter and form. so that all those substantial forms which go by the name of vegetative souls in plants , and in brutes by the name of sensitive souls , are nothing else but vain illusions , since atoms and corpuscles are the internal principles of all the sensitive operations which we distinguish in living creatures . five of these operations are thus numbred , ( viz. ) seeing , hearing , smelling , tasting , and touching . to these we may add respiration in all animals , or the greatest part of them , and speech specially in man. these operations are not made after the same manner in all animals , for man the noblest of them all , is neither sharper sighted , nor quicker of hearing than the rest : and in the same respect the other senses are much more perfect in other animals than in man. the lynx is sharper-sighted , the hare hears more distinctly , the dog smells better , the ape enjoys a more exquisite taste , and the spider a more delicate touch : for all these kind of operations are purely natural and animal , and do not depend upon the will or reason , but upon the sole disposition of atoms , and the construction of the organical parts . chap. ix . of sight , its organ and object , ( viz. ) light. sight is the chiefest and most noble of all the senses , whether we consider its organ and object , or the operation of it by it self , and the necessity of it . the eye is the organ of sense , its object is a coloured and lucid body , for without colour and light there can be no seeing . the eye is made up of three tunicles , ( viz. ) the horn-like , the grape-like , and the net-like : this last is in the bottom of the eye ; the grape-like tunicle has a perforation called prunella , and the horn-like is the outward covering of the eye , some part of which we call the white of the eye . the eye enjoys likewise three transparent humors , ( viz. ) the watery , chrystalline , and glassy : the optick nerve , rooted in the brain , and applying it self to the bottom of the eye , brings hither the spirits or visual corpuscles woven together out of a luminous substance . the particulars belonging to the composition of the eye anatomy will teach : let us speak something of the object of sight , and first of colour . colour which bodies exhibit to us , is nothing else but light reflected and interrupted by the angles of the atoms , and the very small cavities in the extremities of bodies , as also a diverse reflection and refraction of that light , upon which the variety of colours depends . experience favours this doctrine , for galls being broke and thrown into artificial or natural vitriolated-water , give a black colour like ink ; and hereby is known whether waters contain any high of vitriol , iron , or copper : for mineral-waters when they pass through an iron mine by an addition of galls grow black , but others not ; and this blackness is not any physical and accidental quality produced in water by the throwing in of galls which are not black ; but this change arises only from a new position of atoms and corpuscles , whereby the rays of light are bended and broken after a new manner . the same thing happens if you mix minium which is red in its own nature , with wine-vinegar , for that will turn white ; and the yolk of an egg mixt with turpentine looks altogether like a white kind of cream . now in all these and other experiments nothing happens besides a perturbation of atoms which take a new place , and reflect or refract light after another manner , without any production of any new accident . nor is light any accident or physical quality , as the disciples of aristotle will have it , but a real effusion and spreading of corpuscles , which flow from the substance of the sun and upper stars , and more or less penetrate through the empty spaces of the air , as the air is more rarified , or more condensed . it will be convenient to remember here , that we place the sun in the centre of the world , and say that the sun is of one and the same substance with gold , gold melted and purified , and that its glittering and rayes is properly that which we call light , and which is reflected upon all the bodies of planets , amongst which , the earth only is supposed habitable ; these sun-beams are nothing else than that which we call light , so light is a certain thing compounded of the atoms of gold , by a mutual connection amongst themselves bound together , and which tye all the parts of the world to their centre the sun. from whence it is easily gathered , how all things act by vertue of the sun , and that the sun it self also is an helper that man be produced from man. the truth of this our doctrine appears from those things which we brought from monsieur bezancon's experiment . light therefore is of the same nature with gold and the sun , and is therefore gold , or the sun rarified , and air in the day-time is full of this dispersed gold ; so that in breathing we draw in some atoms of this rarified gold , which brings life to us , in bringing to us the principle of natural heat , and radical moisture . no wonder that aurum potabile is of so great esteem , and sought for by every illustrious personage to restore health : but since true aurum potabile is scarce , by reason of the defect of a solvent , and of a natural and radical vehicle , god provides for this , by giving us light , which we take in by the air , which serves instead of a vehicle to it . light therefore is our life , and preserves it ; and we say of a man that is dead , that his light is extinguished , and of a man tha lies confined in a dungeon , that he dwells amongst the dead . upon the occasion of this sentence which i have thought fit to confirm , i observe that light is the universal spirit of the vulgar , varying according to the subject it meets withal ; and that the same is that famous dissolvent from which only , or by the addition of common gold , may be made the universal medicine . but for as much as to the obtaining this effect there is required that this light be made liquid , and out of it be made a living water , and stream , or rain of gold , which few can perform : from hence it is that few possess this supream remedy . i observe , secondly , that light excites the seminal spirit , which is of the same nature , and is contained under divers seeds , and divers coverings , and that the same light produces in us and reproduces those spirits which are called vital and animal , and which are nothing else than luminous corpuscles which are always in motion , whilst they take air , and together with the air , the light annexed , without which their motion ceaseth . we see also that a man dyes for want of air , and by the hindrance of respiration ; and these spirits are more dulled by night than by day , and so do partly fail in the body , the light failing : and unless there did still continue some luminous and solar spirit in the air , or if the stars did not afford a sufficient quantity of it in the night , in the night it were impossible we should be able to escape death . besides we may observe that by this light , which penetrates and creeps through the bowels of the earth , mettals are produced , for it is their seed lying invisibly hid in their bodies : we may say likewise , that every living thing receives life from this light , so that we live by gold only , we subsist by the benefit of gold , and all things are filled with gold , that is , with the sun rarified , and expanded through all things , through all the most secret places , and through our very hearts , whose motions will cease when the light of the sun and other stars shall cease ; whose motion will likewise cease at the end of all ages . by the help of this doctrine we understand what the antients meant , when they said all was full of jupiter and gold , and that the commerce of heaven and earth was bound together with a golden chain : that the universal medicine cannot be extracted but out of the water of the beams of the sun and moon . by this means also we comprehend the truth of the saying about apollo and his golden hairs , and we shall know that which the philosophy of the antients could not explain , to wit , from whence the motion of the spirits in our bodies proceed , and in what the life which we enjoy does properly consist : and so even the new philosophy will no less labour in explaining the essence of life , unless it follows these our principles . as many as shall have been sufficiently illustrated by this light , will here find a secret for the nobility , by which for many years they will be able to preserve health and vigor beyond the ordinary term . i say enough of this thing to move illustrious wits , as being enlightned people , to enquire into the nature and effects of the light and colours which we see , which the sun produceth in the rainbow , and in the peacocks tail , where , by the help of a microscope a thousand golden threeds are seen . nor is there any reason why we should stand amazed at the sight of these colours , since they are nothing else , than light reflected and refracted , wherein all colours are contained , as i have said ; for it is of the same nature with gold , out of which all colours may be produced , although the yellow only is apparent . they who have divers ways dissolved gold , and mercury , or crude gold , have there found all of them as many colours as ever they had seen , and many more colours than they knew . chap. x. how illustrated objects are seen . aristotle and his scholars will have vision to be made by certain qualities commonly called the intentional species , which , as is reported , joyn the visive power , that is the eye , with the visible object , and the powers represent the object . these species according to this opinion are discernable , and are in the air as in their proper subject : but this is not to be endured , for if these are accidents , and have air for their subject , the air being changed by the least breath of wind , the accident would pass from one subject to another , which is refractory to the principles of these philosophers . these species bring in a great many other difficulties , which relate to their nature , production , propagation in the air , eduction , extension , and reception into the eye ; all which cannot be solved without captious contensions , and when all shall be throughly canvased , no body will be e're the wiser , from whence it happens , that all these accidents which are neither bodies nor spirits , i am forced to send back to school with their doctors . some believe vision is made by an emission of visual rayes out of the eyes ; but neither will this opinion subsist , in as much as it supposes , that to see an object ten leagues distant from us , it is of necessity that the eye should send corpuscles thither , and even to the very heavens , to see the stars there . gassendus would have vision made by the species or figure of the object , composed of corpuscles or most subtile atoms proceeding from the object , and received by the eye : but it cannot be conceived , that a man placed in the midst of a plain can continually emit ( without diminution ) corpuscles from every part , or that these corpuscles can be in the air without perturbation and confusion at the same time , whilst other objects emit an infinite number of theirs ; and all this transmitted in a right line through the vacuities of the air , from whence it follows that through one , and that a little space of a vacuum in the air , that vast number of atoms or corpuscles must pass without penetration and confusion . gassendus answers , that the difficulty arises from this , that we do not enough conceive the subtilty of atoms , nor the rapidity of their motion . this reason does not satisfie , since we know that the vacuities of the air are not greater than atoms . how then can a thousand atoms of matter pass in a right line through one only vacuum , no bigger than one single atom , without penetration ? this difficulty , besides some others , hath moved some philosophers to say that the eye is a natural seeing-glass , endued with such a convexity as those glasses have which are put into perspectives , by which we see things a great way distant . these philosophers say , that light , wherein is contained every kind of divers colours , as it is determined upon the objects by the angles of the atoms , does also comprehend all kind of objects too , and represents them with all variety of colours , according to the divers determination of the objects : or to say more truly , that light represents it self to the eye , as it is determined by objects , and it is certain we see nothing but light , and colour , that is light with its determination ; and when we distinctly see an object , its extention and figure , that proceeds from nothing else than that we see light determined by the dimensions and circumstances of the object . the nature of light therefore is solely to be considered , and it will no ways hinder , but that we shall avoid all the difficulties of the others , by embracing an opinion which rests upon truth , which very well , and with the consent of all , conceives that light is seen by it self , nor is there need of any species to see light : and since we , to speak properly , do not see the objects , but light the object of sight , there is no necessity , that the object should transmit accidents or corpuscles , as if light could not be seen of it self . from this doctrine , that which appears new , follows , that light is to be considered in a threefold state ; and first of all in the quality of the object ; secondly , in the quality of the term. the first state is light , determined by the object , the second is light expanded in the air , the third is light received by the eye , and represented with all its determinations . and this is it which we call the image of the object in the eye , as it were in a glass . in prosecuting this subject , we might have treated of the reason why we see objects by the help of perspective glasses multiplying their figure ; or by microscopes , a new invention , by the help of which many things are discovered which before lay hid , such as are worms in wine vinegar , gnats in water and dew , as also , pores in glass , and a thousand little animals in seeds . but of these i shall say nothing now , since i have done it already in a little peculiar tract , which i will print the first opportunity , where the application of the principles of my physick will be seen to explicate more illustrious things which are discovered by the help of microscopes , if the reader pleases to spend his time to see and judge of what i say concerning these things . chap. xi . of hearing , its organ , and object . the organ of hearing is the ear , composed of a cartilage and hollowness's , wherein the air insinuating it self by its motion causeth sound . besides these external and apparent particles , there are others also internal , which are composed of membranes , as also some little bones and included air , the auditory nerve doth also run down thither , that it may bring the animal spirit , necessary to all the operations of the senses . the object of hearing is sound , to wit , the motion of two or more bodies mutually meeting one another ; and as no body that wants heat and light is the object of sight , so no body that wants motion can be the object of hearing : or rather , as light alone , without the intervention of any other medium , is the object of sight , so is motion the object of hearing , so that there is no necessity to have recourse to the pretended quality which is commonly called sound ; nor to any intentional species , no , nor so much indeed as to corpuscles sent out a great way off . i say therefore , that as light is seen by it self , and truth immediately and without any other intermedium is known by it self , so motion is apparent of it self , without the pretended qualities of aristotle , or corpuscles of gassendus , except those of the air , which are in motion : for they being wanting or stirred up by an opposite motion , little or very little is observed of it . the motion therefore of bodies , is the object of sounds , but there is a necessity for a fluid body to be present , that it may be violently moved to and fro , which happens in irregular sounds , or with method and measure ; as in musick , and the use of instruments . this fluid body is sometimes intercepted by two solid bodies , and is forced to go back with violent motion . chap. xii . particular questions concerning hearing . the first question is concerning the penetration of sounds , and it is asked , how it comes to pass that a sound constant in motion can more easily penetrate through a thick wall , than through glass or water ? i answer , that the thickest walls have great cavities , into which the air insinuates it self , or lies shut up in them whilst they are building : after which manner without doubt it is shut up in guns made of melted brass , which is the cause that when they are tryed , they sometimes burst asunder , which hapned about two months ago at niverina in a field near st. germans . air therefore is more easily shut up within walls whilst they are building , than in guns whilst they are casting : and this included air , receives its motion from the external air , and communicates the same with that which is found in the breech or adverse part of the gun. which thing does not happen in glasses , which have but very small pores , into which the external air cannot enter , only light and the most subtile air enjoying this priviledge . from hence it follows , that bodies which have none , or but very small vacuities , and contain no air , or but very little , are more surd , and less resounding , as gold , and lead , however lead is more surd than gold , although it hath more frequent vacuities , but they are less regular ; for since it is endowed with more pores than gold , it ought to give a greater sound than gold. for to the making a sound , it is not sufficient that the body contains air , but that the air be so bound up that it cannot sind a way out : and as to the sound of bells , that depends upon the air intercepted between the clapper and the bell , and wandring round the compass of the bell , before it can get out , and drive on other air , yet so , as that it presupposes air shut up in the pores of the mettal . the second question regards the propagation of sound ; or the sound of bells and guns are heard a great way off : but the reason of this is not difficult to be given ; for the air violently driven on , because it is easily moved , gives a sound according to its motion , greater , or lesser , and because the motion of air is not momentaneous , so the sound likewise is not in a moment brought to the ears . certainly the air that is impelled , drives on other air on every side , until that circular motion ceaseth , as we see when a stone is thrown into a pool the water is moved in circles : this motion in respect of sight is not in the air , we see the stroak ere we perceive the sound , for light is determined in a moment ; nor does a contrary wind hinder light as it doth sound ; for light does not depend upon the motion of the air , and the light of the air is fixed , in the same manner as the centre of the world , from whence it draws its origine , to which it is firmly and immoveably annexed , at least that it be not condensed and grow thick . the third question regards the repetition of sound , and is called eccho ; and it is nothing else than a repercussed and reflected motion of the air by hard bodies , or retained and renewed by other air shut up in the cavities of bodies , and if there are many cavities in a streight line , there are made many reflections , and the eccho is multiplied , and that more or less distinctly , as the reflections are more or less perfect , and the ear more or less distant from the angle of reflection , which is always formed right forwards , and is streight , unless there be some hindrance , and hath always a certain and determined distance . fourthly , it is asked how it comes to pass that the strings of two harps tuned alike , although they be distant two or three paces from one another , the one being struck , the other will give a sound ? i answer , that the air of one being struck into motion , does by its motion excite the motion of the other , which is constituted in the same state , or tuned alike . for here to alledge sympathy , would be nothing else but to flye to the sanctuary of ignorance . fifthly , it is asked , why some sounds are sweet and very pleasant , and others on the other hand harsh and displeasing ? it is answered , that this proceeds from a diverse motion , and from the ruggedness and smoothness of bodies , as also from the smiteing of the air that is driven to and fro . sixthly , it may be enquired from whence the noise in the ears proceed ? and it is answered , that this inconvenience proceeds from a motion of the interior air , against nature , which sometimes happens from the breaking in of foreign corpuscles , or from the solution and emancipation of some atoms , or from the pulse of the arteries , or motion of vapours , which striking against the drum of the ear , make that humming noise of the ears . lastly , it is asked why some people hear better than others ? and we may answer , that this proceeds from the impurity of the interior air : for not to say any thing of those that are born deaf , or have their organs ill formed , or have no interior or included air ; or of old men , in whom this air is dissipated , or of those whom a kind of thick humor falling upon the organ after a long disease makes deaf ; or who are wounded , or have an imposthume in their ears , i say that those who have most of this interior and purer air , have their ears more accurate , and their hearing more distinct , if withal the auditory nerve be well composed . chap. xiii . of smelling , its organ , and object . smelling is an action by which we perceive and distinguish smells ; the external organ is the nostrils , the internal are some glandulous and spongy parts like teats , which descend from the brain to the nostrils , or the olfactory nerve ; or odours which affect the spirits contained in the nerve , and move them ; and these spirits being moved and stirred up , carry the sense of the odor to the common sense . the object of smell are odours , in quality not distinct from bodies , but are rather atoms or sulphurous particles going out of bodies , their figure is hooked and adhering ; from whence it comes to pass that they adhere like oyle or fatness ; and are preserved a long time in chests among cloaths , especially woollen ones . and therefore contagious particles lye hid for many years in ward-robes ; and they who frequently visit those that are sick of the plague , do not use woollen garments , but linnen ones , to which the contagious particles do less adhere . from this doctrine it appears , that smells are little bodies which issue out of all compound natural bodies , especially living ones ; by reason of their frequent agitation ; and which have pores more open than bodies not animated . besides , it appears that these corpuscles do never go out of bodies in greater number , than when they are a dissolving ; after which manner , a smell exhales out of gold and silver dissolved , excelling that of musk and amber . from antimony dissolved , an oyle is drawn of a very grateful smell , and by another way a sulphur is drawn out , not to be endured for its stink . and by the help of these odoriferous corpuscles dogs hunt hares , and find out their forms , and by this means they discover their masters foot-steps : it is an argument that this is done by the help of these corpuscles , because they are dissipated by wind , and hindred by dew , and experience teaches that those that handle musk , carry the smell of it a long while about them : from whence it is known that these very small bodies are adhering , and that they have hooked figures , and that they do please and tickle according to that proportion which they have with the organs . chap. xiv . of tast , and its object . tast is a sense natural and proper to animals , and by the help of that they distinguish savours , making a difference between the grateful and the ingrateful . the organ of this sense is the tongue and palat , and it is done by the help of spongy flesh , and of nerves which terminate in the tongue , and ●arry the animal spirit to the organ , and the savour to the imagination . savour the object of tast , consists in certain saline corpuscles of aliments , or other bodies , out of which they come , and pleasantly or unpleasantly vellicate the tongue and palat , according as their figure is more or less rough and pungent , or smooth and round , and more or less adequetated to the organ . since savours are corpuscles of salt , it follows that they differ according to the diversity of salts , to wit , that they are sharp , sweet , bitter , sowre , and the like , according to the nature of the salt that bears rule in their composition , and according to the quality of corpuscles coming from elsewhere ; which change the natural savour of things , as wine , by the addition of water , loseth both its strength and savour , although in this condition it is more grateful to some , than when pure wine . from whence we know that the diversity of tasts does not proceed from the sole diversity of savours , but also from the diversity of the organs ; and hence it is , that all people do not relish alike one and the same thing ; nor have all people a tast equally delicate , from whence it comes that some are delighted with those meats that others abhor . the organ also is sometimes so ill disposed , and the tongue burdned with so great a quantity of ill humours , that things of the most grateful savour seem insipid , as also things not very sweet seem bitter ; which thing happens in a double and a continual tertian ague , by reason of the dominion of choler . chap. xv. of feeling . feeling is a general sense extended throughout the whole body , and is made by the help of membranes , such as the skin , the scarf skin , and the skin that covers the bones called periostium , and others that are internal ; and this sole sense distinguishes every thing that by its contiguity brings pleasure or pain . the object of it is hot and cold , soft and hard , moistness and dryness . concerning these different qualities of a body we have treated elsewhere ; excepting heat and cold , as which are not physical accidents , but two particular bodies . heat is a heap amassing or flowing together of sharp pointed corpuscles which penetrate into solid bodies , and do there cause a division , and do dissolve the more perfect bodies ; and this is what we call to be set on fire , and to be burnt : for fire does not burn wood , but by dissolving , nor dissolves it but by burning . cold is an heap amassing and flowing together of atoms and corpuscles of a blunt and plain figure ; and hence it is that cold does not penetrate into the body but with pain and torment , as also it excites a frequent motion of the parts , or shivering . besides there are not wanting some particles so gross as to stop up the pores of the body , and to drive the heat into the inward parts , which we call antiperistasis , by reason of which the included heat becomes stronger , which is the cause why the heat of the stomach in winter time is greater than it is in summer , and why wells are warm and reak like smoak . for the same reason , heat being shut up in our bodies by the external cold , sometimes such like fumes are raised up in the brain , which are not without a great deal of danger . feeling is several ways performed , and first of all by application , where body is moved to body , and hand to hand , by penetration , in making a solution of that which was whole ; as a needle pricking the hand . secondly , feeling is made by separation , one body coming out of another , which if occasioned by nature , is always accompanied with pain , as in non-natural ejections . thirdly , this sense appears in the motion of those bodies which are contained by others ; for sometimes they move themselves with so great force , and do so press , rend , and tear , that they excite pains not to be endured , as in violent head-aches , the pleurisie , and pains of the gout and cholick . chap. xvi . of the speech , pulse , and breathing of man. voice is common to all perfect animals as well as men , but so is not speech , or an articulate voice . brutes express their sense of things by natural voices : and men their interiour speech , to wit , thoughts , by outward speech as its interpreter : and this is done by the motion of the tongue , as also of the air after a certain manner driven to and fro between the teeth , and the fluctuating windings and turnings of the throat . this motion is natural and voluntary : for discourse or speech is an expression of an action of the soul , to wit , of thought : but this thought cannot be outwardly made manifest , without the command of the will , or the strength or weakness of the imagination . the dilatation and contraction of the lungs , as also the action of the muscles of the breast serve to the formation of speech , and a voice becomes sweet and harmonious , when the lungs and the aforesaid muscles act methodically , as also when the air is duly reflected , repelled , and interrupted by the passages and turnings and windings of the rough artery , and where the corpuscles of this natural little tongue are less rough and more free from strange bodies . the diaphragm , stomach , and belly move when we speak , and follow the motion of the lungs , and the muscles of the breast . the pulse is nothing else but a percussion of the arteries , upon the variety of which , the difference of pulses depends . the cause of the pulse according to aristotle , is the natural heat of the heart , according to galen it is the moving faculty ; according to harvey , this motion of the heart , and pulse of the arteries depends upon the circulation of the blood , which we will examine in the next chapter . breathing comprehends two actions , inspiration , and respiration , by the action of the first , the lungs receive the external air , and by the help of the last they drive it out . the first is made by a dilatation of the lungs and breast , as also by the motion of the diaphragme , by which the lungs are opened like a pair of bellows , and are by that means filled with air , the second is made by a pressing downwards of the diaphragme , by which the lungs are unlocked , and the air driven forth . breathing conduces to the tempering the heat of the heart , and to the exciting and preserving natural heat , besides it conduceth to the forming the voice , to perceiving smells , to expelling excrements , and dissipating the fumes of the blood , and lastly to produce vital spirits , in promoting their motion , by which it happens that we dye when breathing ceaseth , or when we take our last breath . chap. xvii . of the motion of the heart . that i may rightly explain the motion of the heart , i suppose it is moved by two different motions , the first of which is natural , the second against nature . that resembles the motion of machines and clocks , which are moved by help of strings and wheels . so the heart is the principal and chief wheel of this animated machine , and moves and drives on all the others , and takes its motion from the weight and impression of certain fiery and coelestial atoms , which like the silk-worm are shut up in the seed and its covering , and which give motion to it , until they flye away from it , which slight of the atoms death follows , and an end of motion . the authors of the circulation of the blood , deduce the motion of the heart , from the bloods entring into it , saying that the heart is opened by the motion commonly called diastole , the blood entring into the heart ; and that by the motion commonly called systole , the blood returns back , and this returning , is the cause of those two motions ; but it is more reasonable to say , that the motion of the heart hath its principle in its self , for it is vital , and the passing through of the blood is rather an effect than a cause of this motion , for the heart opens it self before the blood enters in , nor does the blood go out , but as it is driven by the opened heart . the second motion of the heart is accidental , and against nature , and proceeds from the intemperies of the blood that passeth through the heart , and which impresseth this febrile motion , whether as being more hot and subtile than it should be , or having certain foreign corpuscles mixed with it , or being too thick and viscous , or else offending in quantity , it overwhelms the heart ; and hereupon depends the difference of motions , contrary to nature , as also the difference of pulses and feavers ; from hence proceeds the palpitation of the heart , intermitting pulses , convulsions , suffocations , and sudden death . and it is commonly said that the life is in the blood , nor does any thing hinder why we should not say that death is in it too , when it is corrupted , or very sharp and corroding , or unfit for motion , and containing such like bodies as lie hid in venoms and narcoticks . the motion which is observed in the hearts of animals taken out of their bodies ; as for example , that of a viper , which continues a long while , does not disanul circulation , but only lets us see that circulation is not the cause of the natural motion of the heart , and if you stretch it never so far , it is only its condition which makes it continue , and keeps the same in its natural state . whatsoever we say concerning the heart and its motions , does not make up that idea which we conceive in our mind , nor does it satisfie the mind of the reader , who expects we should explain from whence this motion of the heart while it is in its natural state proceeds , and what is the cause of its immoderate motions . that i may therefore satisfie the reader , i affirm the natural motion of the heart to be in the motion of the vital spirits , shut up in the central vacuum of the heart , where they are detained by little membranes , made firm by the interweaving of fibres , and of thin threads , so that they cannot escape out , since the pores of these membranes have a figure opposite to the pores of those spirits or vital atoms : and seeing that atoms enjoy an actual motion , and which can no more be separated from their essence , than intelligence from an angel or separated soul , or the inclination from the will , it follows , that they are always in motion , and by their motions by turns dilate the heart . this doctrine supposes what has been said of vital spirits , being as it were the internal principles of life and motion , as also of the essential and proper motion of atoms , and of bodies compounded of atoms ; but it is convenient that we remember that we have said , that motion is natural to atoms , and that god who hath created them essentially moveable , preserves their motion and moveable nature in the same action that he created them . besides it may be convenient to remember , that there are such a sort of atoms which may be detained , and constitute the parts of a compound body , and others , which are not naturally such , yet may be shut up , such as those are , which we have said are shut up in the central vacuum of the heart of living creatures : and these indeed are shut up by the decree of the creator , and the determination of the seminal covering . the comparison of an angel , and the rational soul seems to contribute much to the illustrating this doctrine . an angel is a certain indivisible , spiritual thing , and an intelligence free from matter ; and the rational soul is no less a certain indivisible spiritual thing , endowed with understanding and will as an angel , yet they differ in this , that thesoul is consined , or , as being a part of the compound , can be consined by a material body , whereas an angel neither is nor can be confined , which notwithstanding does not hinder but that it may be shut up into a body , as it were an assisting form , yet it hath not any respect to an internal and substantial form. besides i look upon an angel , and consider it under the notion of atoms naturally free , and the rational soul under the notion of those which are subject to confinement . it is true , that a rational soul going out of this dungeon or physical prison , by reason of the corruption of the body , which permits it a free exit , is like to an emancipated atom , which being free from the bonds of the composition , never returns thither again , unless that be restored to its pristine , or to a better condition . chap. xviii . of the irregular motion of the heart , in animals , and of feavers . i cannot but say something of the inordinate motions of the heart , stirred up by divers feavers , and from that occasion , discourse of the difference of feavers , their causes , and remedies . feavers are either diary , ( viz. ) an inordinate motion of the spirits which are agitated and disturbed by emancipated atoms ; or they are hectick , which attack the fleshy and solid parts : and these feavers are excited by emancipated atoms , which insinuate themselves into the substance of our bodies , and are the cause that the corpuscles of the radical moisture are driven away , and exhaled ; by reason of which , the body is sensibly dryed . the other feavers consist in the humours , and in their fermentation and ebullition , and when this fermentation never remits , the feaver is continual ; where it keeps its periods by turns , it is an intermitting feaver , and it is called either a quotidian , where it comes every day , or a double tertian , or quartan , as phlegme , choler , or melancholly predominate . when it comes one day and not the next it is a tertian , when it remits for two days it is a quartan , when it rages for two days together , and remits the third , it is a double quartan : and all these fits , or redoublings , are owing to emancipated atoms , or relaxed corpuscles , which provoke , move , and stir up this or that humour , which cannot be done without an agitation of the heart , and a manifest pulsation of the arteries . that which in this subject is difficult to be explained , consists in the regular fits and intermission of feavers ; that is to say , what is the beginning , and what the cause of this flux and reflux , and of this periodical motion and state of rest , and how it comes to pass that phlegme ferments daily , choler but every other day , and melancholly after two days of rest . physitians say this motion proceeds from the diversity of humours , and that phlegme has its motion and fermentation every day , choler every other day , and melancholly every fourth day . but the physical philosopher examines this difficulty more nearly , and the sick person has reason to rest satisfied , when the physitian knowing the quality of the feaver , administers remedies which evacuate the offending humours , and prohibit the generation of the new ; and by this means , the cause being taken away , they raise him up , and restore him to health . the physical philosopher who enquires into the true causes of the motions in nature , and does not like the physician precisely respect the health of this or that person ; but endeavours to discover the truth of all things , supposeth first , that there is no humour in our bodies which goes on from rest to motion , unless it be stirred up by some agent and mover . so it is questioned , what may be that principle by which choler after twenty or twenty-four hours rest is stirred up , and what should excite the fermentation of melancholly , after it has sat down quietly and unmoved two days , or there abouts . physicians who are truly philosophers , and ought to be so , teach us , that in a cachochymick body there is always a new generation made of these sort of humours , and when they are already arrived to a due state of plenitude , some sooner than other some , and sometimes where there is a complication , many of them go on together to a fermentation ; and that all this proceeds from the different nature of humours , and their more easie or more difficult motion , as also from a greater or lesser quantity of one or more humours . but it may also be asked , what is the principle of this agitation or fermentation in that state of plenitude , and for what cause these febrile motions are so very regular and periodick ? here , and every where , we will speak bona fide , and without a fallacy , and say according to our principles , that the atoms asserting their liberty , with every dissolution of the aliment , chyle and blood , as we have said elsewhere , do by their sharp-pointed figures tear the internal membranes and tunicles of the stomach and intestines , as also excite those horrours and tremblings at the beginning of the fit , and which are longer , or shorter , and more , or fewer , according as their figures are more or less aculeated and rugged , or smooth and orbiculate . according to this principle we may say , that the atoms , from the first digestion of the stomach challenging to themselves a liberty , and being weary of the covering of phlegme and salt-water , do daily stir up this agitation ; but those , which in the dissolution of chyle , withdraw themselves from servitude , and which abound with a sulphurous water , which we commonly call choler , do stir up a motion more slow by a day than the former , and as many as are emancipated after the third concoction and dissolution of the aliments , and are wrapped up in adust blood , or that black excrement which they call melancholly , do produce this febrile motion two days slower than the first , according to these different dissolutions . where we must first of all take notice , that the shakeings in the motion of these differing humours are not equal , nay , not in the very fits of one and the same feaver , proceeding from one and the same cause , but which hath different degrees of activity : to which thing , besides what we have said , the quality of the food given to the sick person in the time of the intermission doth much contribute . secondly , the fits of one and the same feaver are not so very regular , but that they frequently are perceived sooner or later , as the atoms the disturbers of health are sooner or later set at liberty . to which thing the regimen of the sick persons manner of living does not a little contribute . hence it follows in the third place , that the true remedy of intermitting feavers doth consist , first , in an order of living . secondly , in an evacuation of peccant or strange humours , which hinder , retard , or interrupt , or precipitate the digestion of aliments , which must be well observed by an experienced physitian ; and lastly , the parts which serve to the first concoction are to be strengthned , because their faults and defects can never be corrected afterwards . moreover if it shall happen that there are some emancipated atoms , as without doubt there are more or less of them in all bodies , they are to be expelled by transpiration , or their figures to be inverted by remedies called febrifuges . for experience teacheth us , that there are some of those sort of remedies very profitable , which are administred with extraordinary good success , and which are not fruitlesly administer'd by me : and i have now some of these sorts of remedies found out by me , and administered , which in one day have cur'd the quartan and double quartan . i speak the truth ; but i should injure the truth , if i should go so far as to say that my remedy is infallible : for truly i believe , and not a few of the most eminent and ablest physitians of the faculty in paris are of the same opinion with me , that there is not a remedy which can be called infallible and made publick . of which thing , in the occasion of the fermentation of humours , i will a little more specially treat in my philosophical reflections , which in a little time will see the light. i only add this here , that the heat which follows the shakeing , does proceed from an agitation of the spirits , stimulated by the violent motion and repeated stroke of the emancipated atoms , which are at last expelled through the pores of the body , as the rebellious angels were thrown out of heaven by the more powerful good spirits . chap. xix . of the circulation of the blood. as many as have delivered themselves from the prejudices of antient physick , and vulgar philosophy , have taught , after harvey , that the blood in our bodies is moved in a circular motion , from the extream parts to the centre , and not from the centre onely to the extream parts , as was heretofore believed . gassendus does not disapprove this opinion , although he does not embrace it , for reasons alledged in a particular treatise set forth by him . i use his reasons to establish it , as being better founded in reason , and more agreeable to the disposition of the veins and arteries . let us see therefore how the circulation of the blood is made , according to harvey , and the most learned physitians . the blood , say they , passeth into the heart , from the vena cava , and arteria venosa by two valves , where they are ended , and as often as the heart dilates it self , a drop of blood falls into each of its cavities ; and as often as the heart contracts it self , the blood passeth into the lungs from the right cavity , through the vena arteriosa , and from the left cavity , into the aorta ; so that the blood is moved from the extream parts of the body , to its centre , into which it is carried by the vena cava , where it exonerates it self in the right cavity , from whence it passeth into the vena arteriosa , and drives on the blood which is contained in that , through anastomoses already discovered , and through pores less sensible into the arteria venosa . and as much blood as the arteria venosa hath received , so much of it deposits into the left cavity , from whence passing into the aorta , it is carried into the extream parts of the body , through branches which go to the branches of the vena cava , from hence the blood being brought into the trunk , continuing its journey by the same way it returns to the heart , and by the same reason as i said , it wonderfully and without intermission performs the circulation . this circulation of the blood relies upon some experiments , the first of which , is taken from blood-letting : for chyrurgeons when they bleed a vein , tye the arm above the orifice , and if they put their finger upon the vein on the other side of the ligament , the blood is stopped immediately : from whence it is apparent , that it comes from the extremity of the fingers to the trunk , and not from the trunk to the extremity of the fingers , but by circulation , of which we are discoursing . the second experiment is made , if a vein be tyed in a part of the body , separated from the artery : for it will be emptied on that side towards the trunk , and it will be swelled on the other side ; on that side , that is to say , from whence the blood according to this opinion ought to proceed . there is nothing therefore so certain as this circular motion of the blood , and its passage into the heart , but here are three things to be observed . first , that the motion of the heart does not depend upon this circulation of the blood , although it conduce to its conservation and inordinate motion , as this circulation is made more or less hastily , and as the blood is more or less temperate in the disposition of its particles , and in its saline serosities which serve for a vehicle to it , and render it more fluid . secondly , that the circulation of the blood as the moderns indeed will have it , may be performed three times in an hour , yet so that all the blood does not enter into the cavities or ventricles of the heart , as not once every hour , but either sooner or later , according to the greater or lesser quantity , or greater or lesser subtilty or mobility of the blood. thirdly , i say , that the blood in some cases , cannot pass out of the arteries into the veins , through the extremities , that is , when the extremities are cut off ; in which case , it goes on another way , through insensible pores , which they call transpiration , or transudation . chap. xx. of the inward senses , and the inferiour appetite . besides the exteriour senses of which we have spoken , there are also found to be in man interiour senses , ( to wit ) the imagination , common sense , and sensitive memory . the first forms a lasting image of objects . the second judgeth of the agreeableness or disagreeableness of them . the third retains and preserves these images or ideas ; which is manifest in dogs , who represent to themselves persons absent , and distinguish both between the good and the evil that hath befallen them , witnessing that they remember the thing by running away if they have an opportunity , or by fawnings . appetite follows the interiour senses , and is common to all animals , and which is performed by the weight of atoms , whereby it comes to pass that an animal hath a propensity , and is driven to seek for that with which it is delighted , and to abstain from that which might bring trouble : so that delight and pain are the two great importances of the life of an animal . pleasure according to the opinion of epicurus , depends upon corpuscles which have a soft , round , and agreeable figure , especially to the brain , as to which the object is represented by the imagination , and from which it is carried by the senses : pain on the contrary , and both of them are performed by those corpuscles , whether they come to , or go from , or continue . in morals , we will speak concerning these passions , as the two scales of sensitive actions ; in the mean time i may here say , that the interiour senses receive these corpuscles , which bring pleasure or pain by the ministery of the exteriour senses ; from whence it comes , that those that sleep , or are lethargick , or apoplectick , feel nothing , though they are pricked : for the brain is filled with strange humours , which hinder the motion of the aforesaid corpuscles , or else that motion is stopped by vapours , brought from the lower parts to the brain , which happens to those that are asleep . chap. xxi . of sleep , wakefulness , and death . sleep is the image of death , for all the senses are at rest , nor is there any motion left but that of the heart , lungs and arteries ; this rest proceeds from vapours arising out of the stomach , which by their clammyness , humidity , and viscousness , do stupifie the animal spirits , and sleep is sweet or restless , according as those vapours are sweet , or abound with corpuscles , or are stirred up from choler , or other things of an irregular figure , or where some emancipated atoms make the disturbance . the mixture of these atoms is often the cause of light-headedness , madness , and hypochondriac melancholly ; and they likewise produce watchfulness , by an inversion and confusion of the ideas in the imagination ; from whence it happens that we see that which we never see directly ; and sometimes monsters and horrible things . this motion of the images or ideas is sometimes so very violent , and there is so great a troop of these emancipated atoms in the brain , that those that are asleep , do sometimes rise out of bed , talk , climbe up walls , bathe themselves , and then go to bed again , without ever waking all the while . death is commonly called a perpetual sleep , and in animals ( excepting man ) it is nothing else than a total dissipation of the vital atoms , or a cessation of motion , in which their life consists . in man these things are not after the same manner , although however all these things cease in a dying man , either immediately , as in a violent death ; or by degrees , as in a natural death ; we must confess nevertheless , that in that respect something else is to be accomplished , to wit , the separation of the soul which god gave him , and which returns unto him that gave it . before we go any further , and that we may make an end of this chapter , and be as good as our word , i am forced a little more specially to discourse concerning the death of those things which have life : for whatsoever is created and compounded of many parts , and liveth , is subject to death . man , who is compounded of a material and organical body , like other beings , dyes at last ; but because he hath an immortal soul created after the image of god , he only dyes that he may live eternally with god , if he be faithful ; and his death is no more than sleep , and a passing into eternity . what a christian philosopher ought to think of this soul i shall declare in the last chapter of this book : here i will say something of his body , as also of its corruption and dissolution . the rational soul never goes out of this mortal body before the motion of the heart is stopped ; this motion , which is not voluntary , ceasing , life can no longer continue , since it consists in this motion . if the rational soul was only in the brain , as duncan and some others will have it , it would be hard to tell why it should depart , upon the cessation of the hearts motion , whilst the rest of the parts are in good order . as for my part , i consider it in its spiritual nature , believing that he must have too mean an idea of this spiritual substance who confines it to the brain , and to the smallest part of it . that opinion which affirms it to be present every where in the whole body , although it operates more particularly in the brain and heart , seems to me to be more reasonable , and for this reason , the soul acting in the heart , the organ ceasing , it departs in the same moment . it may seem a wonder to not a few , that the rational soul should so depend upon the material body , but since it so seemed good to the author of nature , we ought to rest satisfied . the body is endued with organs for the sake of the soul , and the soul is created for the sake of the body , and one is made for the other , and the conjunction of these two make a compleat man. one part onely does not make a man , nor does a separate body make up the essence of a man ; and indeed a dead man is not what he was , 'till he rises again . the soul therefore is annexed to the body by such a sort of tye , that it cannot act but by organs . so that he sees nothing when his eyes are out , he hears nothing when his ears are stopt , and the chief organ being deficient , the soul departs because it can do nothing . this chief organ , to wit , the heart , is deficient many ways ; it may be stopped and suffocated for want of air and respiration , for the atoms of light implanted in the heart at the time of a man's conception , ( the commerce of the solar spirits being intercepted for want of air , ) do sometimes suddenly stand still , they flye away , finding a passage through a solution of the continuum , or through pores made fit by a burning feaver in the heart , all the water of the pericardium being dryed up : thick and viscous blood does sometimes stop the motion of these vital atoms . poyson also does by its acute particles pierce through the heart , and give an exit to these spirits of light , which are tyed to those which the sun bestows upon us , and are attracted by them , returning thither from whence they came . let us see now what the body does in the grave ; it putrifies there , that is , it is dissolved , some corpuscles or atoms withdraw themselves , some part of the body is changed into worms , some of the vital spirits resisting . it is a folly here to imagine any substantial form of the dead carcasse , or to acknowledge partial forms of the bones , flesh , veins , arteries , and such like things , subjects to the form of the dead carcasse , or alone without this form. these are illusions and chimera's . matter is the same , and all the change that happens , consists in this , that when the rational soul is absent , there remains nothing besides matter ; the organs by little and little lose their figure , and having lost their composition , they lose their action , that which was compounded is dissolved , and the greater part goes into dust and ashes ; the luminous spirits recede , and follow the motion of the spirits of their kind : some parts or corpuscles joyned to the putrifying body , purtifie in the place where they are : experience favours this doctrine . a certain servant to a noble-man , whose nose had been by great misfortune newly cut off , freely parts with his own nose to serve his master . this nose being put in the place of that which was newly cut off , took root , and grew together , after such a manner , with a cartaliginous flesh , that it seemed to be natural . about twenty years afterwards , the servant dyes in a far countrey , and was buried , and as by degrees he putrified , so after the same manner , this end of a nose began to putrifie , to be corrupted , and to fall off , parting from that part to which it had so long stuck without withering , whilst the servant lived , the part following the condition of the whole . i say moreover , that the least parts or corpuscles which proceed from a body , the body being dead and corrupted , they also are corrupted , and joyned in commerce with atoms of the same nature , which they do , by inviting them to joyn and come together . and here 's an experiment which every one can understand . it is very well known , that he that puts on a garment , or touches it , leaves upon it his scent , that is , corpuscles which proceed from his body , and which constitute part of it ; and by the help of these corpuscles a dog is able to know his masters handkerchief , hat , or garment from ten thousand others . this being supposed , if the dead man's garment or gloak be put into a press or chest , first , and for some days , when the body that is buried begins to putrifie , there will be a considerable noise and disturbance in the press or chest , enough to frighten children , and other folks too , and the corpuscles of the dead body being attracted by those that are going away , by their motion make this noise among the cloaths : and whereas this attraction is made in a streight line , and these corpuscles cannot pass through the bords , but obliquely , the wood suffering violence , makes a noise as if it were crackt . any one may trye this , and know whether this experiment made by others be true or no : i see no reason to doubt of it : from hence appears that invisible bond of the parts with the body from whence they did proceed . a third experiment may be made , which will serve to the illustrating this subject . take a piece of veal , or any other flesh from the shambles , and with it rub the warts of any ones face or hands , then afterwards fling it upon the dunghil , or bury it , and as that putrifies , the warts will fall off , which denotes that the corpuscles of flesh returning to their whole or greater part , and being violently attracted , do in the same manner attract the warts , and make them go away , which some learned men say they have experienced . we may admire in all these things the providence of god , who hath created atoms , and out of them hath compounded the universe , wherein we find so great a number of wonderful things , which are the subject of our admiration , and convince our ignorance . chap. xxii . of the death of brutes , plants , and mettals . seeing that man dyes , other animals cannot escape death ; let us see wherein it consists . the followers of aristotle are very much puzzled in explaining the death of a dog , for when it is destitute of all sense and motion , it is dead without doubt , yet in the mean time it hath all its parts and organs . what therefore happens to this animal ? it s soul is separated from its body , say they , and the spirit of life is not in him ; they do the beast much honour who speak thus in his favour . but what becomes of this soul ? is it corrupted or annihilated ; or does it subsist apart in some other place , or is it taken into some other body ? no , by no means , say they , it is not , it is destroyed , and that 's sufficient . so it is sufficient to people who don 't seek after the truth : for if this soul be a substance as they say it is a material one , it is impossible but it must go into some other thing , or else be reduced into nothing . it is reduced into nothing say they ; therefore it is annihilated , therefore it is created and made out of nothing , which is ridiculous , and unbecoming a christian philosopher . it is true , this opinion is very common in the schools , but this errour is detected , and they who are wiser than others , say with us , that the spirits of life , or corpuscles of light being altogether dissipated or hindred in their motion , do withdraw and return to their original , and copulate with others which are in the air , so dyes a dog , without the loss of that which god made ; the parts are separated , the spirits seek the air , the body the earth . plants dye like other living creatures , but their death very much differs from the death of animals , for as much as their organical parts do not appear so as they do in animals , nor does a plant dye so easily as an animal : for a plant is not dead so soon as it is pulled out of the ground , its life continues to the extream dryness , or evaporation of the radical moisture , which contains all the spirits of life ; and though the plant be calcined , or burnt to ashes , part of the spirits will remain in those ashes ; for the lixivium that is made , or the salt that is extracted , gives all the savour of the plant ; and where that lixivium is congealed by the cold of the night , the figure of the burnt plant will appear in the very ice . but what is more to be observed , is , that a plant dryed in a kilne , and put into a particular water whose virtue is universal , receives its pristine greenness , leaves , and flowers ; without doubt in this dryed plant some vital spirits were shut up , which are relaxed by the spirits of this water , or the vital spirits exhaling , give way to the spirits of the water we speak of , to take their places . this water is endued with vital spirits , which can fill the place of those that exhale in us , and with this sole remedy life may be prolonged , and the losses of ruined old-age be repaired , by filling up the vacuities of the radical moisture which is dissipated . but you will say , where is this water , it is to be found in light , according to our principles , and certainly no where else . this water is the true elixir-vitae , and the universal medicine of the antients , and it is meet that we use it to the preservation of the most sacred persons . mettals have a more abstruse life than plants , nor is their death more conspicuous : their life consists in a certain disposition of parts , which permits a free motion to the atoms of life and light. this is the state of mettals in their mines , and when they are melted , this liberty is lost , by the intervention of the atoms of fire ; and when after melting they grow cold , they may be called dead , for they are deprived of motion , nor do they perform any action . gold melted when it is grown cold is dead ; it lived in the mine , it is dying whilst it is melting , and it is dead , when cast into ingots . in vain therefore do the chymists seek for the living among the dead , common gold is dead , and good for nothing but to make money of ; but if any one can dissolve this body , and bring the dead to life again by the benefit of that resuscitative water which we spoke of before , he may prepare a medicine , profitable to humane and mettalick bodies . it is said before , that stones want life : but this i meant , that they not a life so notorious as mettals , whose life hitherto is yet obscure enough ; for i have learnt being convinced by experience , that the greatest part of stones are multiplied , and encrease , according to all their dimensions ; and that sand is turned into shells . and this very thing is the cause that i conclude , light to be the spirit of life , that by the benefit of it all things live , the very stones also take their life from hence , seeds owe all their vigour to light , and seeing that light is woven out of thin threads of gold , all things therefore live by the spirit of gold. but the soul of man is spiritual ▪ and a ray of divine light , and owes its life to god and his word , as also it is an immortal substance , as we shall say in the next and last chpater . essayes of natural experiments made in the academie del cimento, under the protection of the most serene prince leopold of tuscany / written in italian by the secretary of that academy ; englished by richard waller ... accademia del cimento (florence, italy) approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing a estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. 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ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - robyn anspach sampled and proofread - robyn anspach text and markup reviewed and edited - pfs batch review (qc) and xml conversion essays of natvral experiments made in the academy del cimento under the protection of the most seren prince leopold of tuscany englished by ric. waller s.r.s. london printed for benj : alsop at the angell & bible in the poultry . . essayes o f natural experiments made in the academie del cimento , under the protection of the most serene prince leopold of tvscany . written in italian by the secretary of that academy . englished by richard waller , fellow of the royal society . london , printed for benjamin alsop at the angel and bible in the poultrey , over-against the church . . to sir john hoskyns knight and baronet , president of the royal society , &c. sir , as your commands gave the first being to this attempt , so 't is but justice to offer it to your self ; and 't was but necessary to crave so advantagious a protection , to defend it against the difficulties , things of this nature meet with , in this censorious age. i shall wave , as less grateful to you , a large description of the happiness the royal society enjoys under such a president , whose perspicacious judgment is actuated by a true desire of promoting real knowledge ; and shall rather give some account of the work it self : it was presented in a publique meeting of the royal society , march . ⅞ by sig r. lorenzo magalotti , and sig r. paulo falconieri , from the most serene prince leopold , brother to ferdinand the second , great duke of tuscany ; and has ever since layn in our library expecting a more skilful pen , to perform what i have here aimed at . the experiments are many , and curious , made under the favour of that prince , by the members of the academy del cimento , men of great ingenuity ; and related with much sincerity by the secretary of that academy ; which society ( i hear ) is now scatter'd , and the hopes of those benefits the learned world might justly expect from them , frustrated . many indeed of these experiments have been made , and shewn in several meetings of the royal society ( before , and since the publication of this in the italian , in the year ) by the honourable robert boyle , esq and other worthy members thereof ; but for all this , i hope it may not prove unacceptable to find the ingenious in other parts of the world , have not thought their time mispent in these endeavours , what contrary sentiments soever some may have ; nor will the agreement between the success of experiments made there , and what has been attempted here ( often with a differing apparatus ) be less pleasing ▪ very many , i dare undertake , are new to most persons , except your self , and upon that account will prove more diverting . i need not add the great expence of care , and charge , and fatigues of the academy in this work ; nor the scarcity of this piece in the original , no small motive to this undertaking ( that it might be obtained with more ease , and at a cheaper rate ; ) which how performed , i submit to your self , and the worthy members of the most illustrious royal society ; begging pardon for this presumption ; desiring onely to subscribe my self , sir , your most humble servant , richard waller . to the most serene ferdinand ii. grand duke of tvscany . most serene prince , the publishing of these first essays of natural experiments , which for many years have been made in our academy , under the protection , and with the indefatigable assistance of the most serene prince leopold your highness's brother , will prove the happy occasion of giving fresh testimonies ( of your highness's great liberality ) to all those parts of the world where vertue is adorn'd with its deserved lustre ; and will create a new sense of gratitude and respect in all true lovers of the more curious arts , and nobler sciences . especially we ought to frame our thoughts to a more humble acknowledgment , as we are more nearly concerned and warmed by the cherishing rays , and invigorating influence of your highness's bounty . which with the favour of your patronage , the incouraging invitation of your mind , and proper genius that way ; but above all , with the honour of your presence , sometimes stooping to our academy , sometimes commanding us to your royal apartments , has bestowed upon it an immortal name ; kindled active desires in our breasts , and given an happy encrease to our studies . these considerations easily demonstrate , with what duty we are engaged to consecrate the first fruits of our labours to your highness's most illustrious name ; since nothing can proceed from us , wherein you can have a greater share , and by consequence more due to you ; nor any thing that may make fairer approaches to merit the happy fate of your generous acceptance . 't is certain , that through the excess of so large and signal favours , we can be sensible of no greater resentments than to find our selves so much obliged to your highness : not that we refuse to bear the weight of so endearing and inestimable an obligation ; but onely because we would wish to be able to offer something not purely your own ; whence we might at least flatter our selves , that we had made some small return which your highness might impute in some degree to our choice , and not wholy redewable to your highness self , or necessity· but we must rest satisfied with the bare desire of so just and deserved a passion ; since these new philosophical speculations are so deeply radicated in your highness's protection , that not onely what is now produced by our academy , but what ever shall be brought to maturity in the most famous schools of europe , or after ages raise up , shall be likewise due to your highness , as the gift of your beneficence : since as long as the sun , planets , and stars retain their glory , and heaven endures , there will remain a glorious memory of one that contributes so much with his auspicious influence to such new and strange discoveries ; opening an unbeaten path for the least fallacious method of search after truth . yet in so great a scarcity of tributes , some little thing presents it self to manifest our grateful observance ; which is the onely joy wherewith we support our deficiency , while all redounds in more resplendant glory to your highness , who having already acted your full proportion of what ever new , good , and great , is at any time to be found in the repository of sciences , has enervated and discouraged all thoughts of emulation in others . this , and this alone are we able to lay at your highness feet , whose continual protection we crave with respect and reverence , begging from heaven the height of prosperity and grandure to your highness . highness's most humble servants of the academy del cimento . il saggiato segretario . florence july th . . the preface to the reader . among all the creatures of divine wisdom , the birthright doubtless belongs to the idea of truth , which the eternal artificer so exactly followed in the vniversal fabrick of nature , that no being was made with the least irregular bias of falshood : but man afterwards , ( in the contemplation of so high and perfect a structure , through an extravagant desire of comprehending the admirable design , and finding out all the measures and proportions of so beautiful an order ) when he aims to penetrate too deep into the truth , frames to himself an indefinite number of falsities , which proceeds from no other cause but his ambition to take those wings nature never design'd ( perchance fearing to be some time or other discovered by him unwillingly in the preparation of her greater works ; ) yet upon these he begins to raise himself , and tho charged with the weight of a material body , stretches forth these pinions to soar higher than the scale of sense leads , and fixes himself upon that light , whose rays , too powerful for his eyes dazle , and blind him . thus we see from mans rashness , the first seeds of false notions came ; from which yet it happens , not that the bright splendor of gods excellent creatures is at all shaded , or by their commerce with them in the least vitiated : since all these imperfections are to be attributed to mans ignorance , vitiated whence they had their beginnings ; when improperly applying the causes to the effects , he takes not from either the verity of their beings , but onely delineates in his own mind a false conception of their relation to each other , and agreement ; not that the soveraign beneficence of god when he creates our souls , denies them to pry , as we may say for a moment into the immense treasure of his eternal wisdom ; adorning them as with the most precious jewels , with some first sparks of truth , sufficiently evident from their retaining notions not to be acquired here , whence we must conclude , they received them from some other place . but it happens through our misfortune , that these rare gems , as they are but loofly set in the mind , yet too tender when she first falls into her earthly habitation , and wraps her self in this clay ; so for a time they fall out of their collets , are sullyed , and worth nothing till by assiduous and careful study , they are again reset in their proper places . this is what the mind attempts in the search of nature ; wherefore we must confess , we have no better means then geometry , which at first essay hits the truth , and frees at once from all doubts , and wearying researches . and indeed she leads into the way of philosophical speculations , but at last leaves us ; not that geometry has not a large field to expatiate in , and travels not over all natures works ; as they all submit to those mathematick laws , by which the eternal decree freely rules , and commands them ; but because we hitherto are unable to follow her in so long , and wide a path onely a few steps . now where we may not trust our selves to go farther , we can relye on nothing with greater assurance than the faith of experience , which ( like one that having several loose and scattered gems , endeavours to fix each in its proper collet ) by adapting the effects to the causes ; and again the causes to the effects if not at first essay , as geometry yet at last succeeds so happily , that by frequent trying , and rejecting , she hits the mark. we ought then to proceed with much circumspection , lest too great a relyance and trust in experience , turn us out of the way , and impose upon us ; since it sometimes falls out , that before the clear truth appears to us , when the first more open vailes of deceit are taken off , we discover some cheating appearances that indeed have some likeness , and resemblance of truth : and these are the imperfect lineaments that are seen through the last coverings that more nearly vail the lovely face of truth ; through the fine web whereof she sometimes seems so plain and lively , that some might conclude , she was nakedly discovered . here then we ought to carry our selves as master-workmen , to discern between truth and error , and the utmost perspicacy of judgment is but requisite , to see well what really is , from what is not ; and to be the better able to perform this task , doubtless 't is necessary to have at some time or other seen truth unvailed ; an advantage they onely have ; who have had some taste of the studies of geometry . nor is it of less use to search among experiments already made , than to attempt new ones , if haply any may be found , that have at all disguised the simple face of truth : wherefore 't is aimed at in our academy , besides what has been invented by us , to try also ( either for curiosity , or as we light upon them by chance ) those things which have been already done , or wrote off by others : observing too well , that under this name of experiments , frequent errors have crept in , and been entertained . this was the first motive to the perspicacious and indefatigable mind of the most serene prince leopold of tuscany ; who in the recess of those daily negotiations , and solicitous cares that attend his high quality , diverted into the rough path of the noblest sciences . but his highness's discerning judgment easily foreseeing that the reputation of great authors proves too often hurtful to the studious , who through too much confidence , and veneration of their names , fear to call in question what is delivered upon their authority ; wherefore he judges it an vndertaking worthy of his great mind to confront with the most acurate , and sensible experiments , the force of their assertions , and with the due rejection of errors , and embraceing of realities , to make so desirable , and inestimable a present to those that earnestly wish for the discovery of truth . these prudent instructions of our most serene patron , received with due reverence and respect by our academy , has not moved us to be indiscreet censurers of the learned pains of others , nor made us bold obtruders of our own sentiments for truths , and discoveries of abuses : but it is our principal intent to incite others also to repeat with the greatest severity , and niceness , the same experiments ; as we have now adventured to do with those of any other person : tho in publishing these first essays , we have , what we could abstained therefrom , that we might by this due respect , gain upon the adversary to believe the sincerity of our impartial , and respectful thoughts . and to the full compleating of so generous and useful an vndertaking , we desire onely a free correspondence with those several societies that are disperced throughout the more illustrious , and noted parts of europe : that with the same design of attaining such high ends , so profitable a commerce being in all parts round about promoted , we may all go on with equal freedom , enquiring as much as possible , and participating of the truth : and for our parts , we will concur to this work with the greatest simplicity , and ingenuity ; whereof 't is no small argument , that when we have related the experiments of others , we have still mentioned the authors name , when known to us ; and that we have often freely confessed , that supposition concerning some experiments , which when put in practice we were never so successful as to bring to perfection . but above all , to prove clearly the unfeigned sincerity of our proceedure , let that freedom suffice , wherewith we have still communicated the essays and experiments themselves to any that , travelling by our country , shewed any desire , or relish of such sciences , moved either by a gentile humor , esteem of learning , or spur of curiosity ; and that from the first time our academy was founded in the year , when the greatest part , if not all the experiments were invented , whereof these essays are now published . if it shall happen , that among them there shall be any found , thought of before , or after the time they were made here by other persons , and made publick , let us not be blamed for it , since we could neither know , nor see all things ; so that no man ought to wonder at the lucky accord of our minds , and inventions with other mens ; nor indeed will we , if we find those of other men agree with ours . lastly , we are unwilling any should imagine , that we pretend in this publication , a perfect work ; or in the least , an exact module of a large experimental history ; conscious to our selves , that more time , and greater abilities are necessary to so vast a design ; as may be seen by the very title we have prefix'd , onely of essays , which we had never put forth , had we not been much urged thereto by persons meriting from us , by their dear importunities , the sacrifice of a blush , for exposing such imperfect embrio's . and now we will close all with a protestation , that we never desire to entertain controversie with any , or engage in any nice disputation , or heat of contradiction ; and if sometimes , as a transition from one experiment to another , or upon what occasion soever , there shall be inserted any hints of speculation , we request they may be taken always for the thoughts , and particular sense of some one of the members , but not imputed to the whole academy , whose sole design is to make experiments , and relate them . for such was our first proposal , and the intent of that great personage , who with his particular protection , and far-reaching judgment , caused us to take that method ; to which sage , and prudent advice we have still punctually , and regularly conformed . the contents . the description of some instruments to discover the alteration of the air. page the description of instruments to measure time experiments appertaining to the natural pressure of the air that the pressure of the air sustains the quick-silver in the tube mr. roberval's exper. of the airs pressure repeated experiments against the airs pressure answered whether the air gravitates , and of its expansion when the pressure is taken off , that the mercury falls , with other experiments relating thereto &c. the efficacy of another fluid joyned to the airs pressure several experiments about the airs pressure to the description of instruments , shewing the alterations happening in the state of the natural compression of the air various experiments made in vacuo of the spherical figure of small drops in vacuo ib. of heat and cold applyed outwardly to the vacuum whether the air reflects the second image visible in a lens of amber in vacuo of the effluvia of fire in vacuo of the motion of smoak in vacuo of sounds in vacuo of the magnet in vacuo of hollow canes in vacuo ib. of the boiling of water in vacuo . of snow in vacuo of the dissolution of pearl and coral in vacuo . of several animals included in vacuo &c. of bladders of small fish in vacuo experiments of artificial freezing of the dilatation of water in freezing of the measure of the force of rarifaction in freezing water to measure the utmost expansion in freezing water of the procedure of artificial freezings tables of several fluids freezing . &c. experiments of natural freezing of common water in air ib. of the same in vacuo . of still'd water of sea water ib. of the power of sal armoniac , &c. in freezings of the metals that keep ice best of freezing a pieee of ice to a table ib. of freezing the dew upon the outsides of glasses of reflected cold experiments about the alteration of the size of vessels , &c. by heat & cold , that the vessel alters before the liquor contained of the alteration of a brass ring by heating in the fire of bodies dilated by imbibing moisture of the dilating and contracting of glass by heat and cold of the same in tinn in brass wires the same proved by a different observable that a vessel also may be distended by weight experiments about the compression of water &c. experiments against positive levity . experiments magnetical about diverting the passage of the magnetic virtue about the magnetic virtue passing through divers fluids about the placing the magnetic in respect of the poles of the earth experiments touching amber and other electic bodies experiments about altering the colours of several fluids of altering water ib. of altering wine of altering a tincture of red roses ib. of altering a tincture of saffron of altering greens ib. of altering violet colours experiments about the motions of sounds of sounds passing equal spaces in equal times ib. of contrary and favouring winds of the equability of motion in sounds ib. experiments about bodies projected of horizontal shot from the top of a tower ib. of perpendicular shot motion imprest , not altered by a new direction miscellaneous experiments of the absolute weight of air to water ib. of heat and cold of a wire seeming lighter hot than cold of the force of heat in rarifaction of antiperistasis whether cold be caused by the intrusion of frigorific atoms of ebullitions by salts , &c. whether glass be penetrable by odours whether glass be penetrable by humidity experiments of light of the instantaneous motion of light of firing bodies with a burning glass of bodies affording light ib. experiments about the digestion of some animals tab. . p. . the descriptions of some instruments to discover the alterations of the air , caused by heat and cold . it is most usefull , and indeed a necessary thing in the making of natural experiments , to be truly informed of all the alterations the air is incident to ; for since it receives into it self , and as it were , embraces all things , leaning on them with its whole weight from a vast height , they must needs all bend under this pressure ; and as this violence which they suffer , is more or less , so are they more imprisoned or enlarged . thus the mercurial standard either rises or falls , at the different height of the atmosphere , or as some think , correspondent to the various temperaments which the air receives from the sun , or from the shade , from the heat , or from the cold , when open , and free , or when shaded and opprest with clouds , when it either rarifies , or condenses it self , and so gravitates more or less upon the stagnant mercury , by which , with different pressures , it forces it higher or lower into the immersed cane . it is therefore requisite ( as well for that experiment which we shall amply treat of in the first place , as for others , which in the sequel of this discourse we shall handle ) to be provided with such instruments that we may be able to assure our selves , what is the true measure , not onely of the greatest changes of the air ; but if it be possible , the niceties of the smallest variation . we will therefore in the first place , describe those which have been serviceable to us , though they may have been already dispersed hence to several parts of europe , so that they will want the pleasing dress of novelty to recommend them : nevertheless , they will not be unacceptable to those that desire a more nice and particular information ( if not of their use , which is easily comprehended , yet ) of the way and artifice of making them . the first instrument to measure the degrees of heat and cold in the air. let the first instrument be that represented by fig. . which may serve , ( as likewise several others ) to shew the changes of the air , in reference to heat and cold , and is commonly call'd a thermometer : 't is made of cristalglass , after this manner . the artificer by blowing with his own mouth ( instead of bellows ) through a glass-pipe upon the flame of a lamp , forces it in one continued stream , or several , at pleasure , from one place to another , where it is requisite ; and by this means , shapes most curious , and admirable works of glass . such an artificer we call a lamp blower . let him then make the ball of this instrument of such a capacity , and joyn thereto a cane of such a bore , that by filling it to a certain mark in the neck with spirit of wine , the simple cold of snow or ice externally applyed , may not be able to condense it below the deg . of the cane ; nor on the contrary , the greatest vigour of the sun's rays at midsummer , to rarifie it above deg . which instrument may be thus fill'd , viz. by heating the ball very hot , and suddenly plunging the open end of the cane in the spirit of wine , which will gradually mount up , being suck'd in as the vessel cools . but because 't is hard , if not altogether impossible to evacuate the ball of all the air by rarefaction ; and the ball will want so much of being fill'd as there was air left in it ; we may thus quite fill it with a glass funnel , having a very slender shank , which may easily be made when the glass is red hot , and ready to run ; for then it may be drawn into exceeding small hollow threads , as is well known to those that work in glass . put the small shank of this funnel into the cane to be fill'd , and by forcing the spirit of wine through the funnel with ones breath , or sucking it back again when there is too much ; you may fill the instrument up to what mark in the neck you please . the next thing is to divide the neck of the instrument or tube into degrees exactly ; therefore first , divide the whole tube into ten equal parts with compasses , marking each of them with a knob of white enamel , and you may mark the intermediate divisions with green glass , or black enamel : these lesser divisions are best made by the eye , which practice will render easie . this done , and with the proof of sun and ice , the proportion of the spirit of wine found ; the mouth of the tube must be closed with hermes seal at the flame of a lamp , and the thermometer is finish'd . we rather make use of spirits , than simple spring water for these instruments ; because , first 't is colder , ( i. e. ) sooner sensible of the least change of heat and cold , and by reason of its extream lightness , it more readily contracts it self , quickly falling or rising . secondly , simple water , how pure and clear soever , yet in a little time le ts fall some sediment , or dregs , which sticking to the sides of the vessel , at last clouds its transparency : whereas the highest rectified spirit of wine , or the like burning spirits , always keep pellucid , nor ever abate of their first beauty . and since it is so clear and cristaline , that at first view 't is hard to discern the bounds between it , and the void space of the neck of the vessel ; we sometimes used to tinge it with the infusion of kermes , or sanguis draconis ; but when we observed , that how light and refined soever the tincture was , yet in time something still adhered to the sides of the glass , and augmented rather then lessened the difficulty , we at last wholly omitted the use of coloured liquors ; the other being discernable with a little straining the eyes . we might here add many other works and curiosities touching lamp working ; but as 't is very difficult to design , and draw things of this nature upon paper ; so 't is altogether impossible to make them intelligible in writing : wherefore our operator ought to be pretty well instructed before , and his art will improve with frequent practice . the second instrument , for the same use . this is but a copie of the former , in little ; there being no other difference between them , but in the length of the stages the liquor has to run : that being double the length of this ; that being divided into deg . this but . that at the greatest cold of our winter subsiding to or deg . this usually to , or ; and at a great extremity of cold one year , to deg . and this to deg . and on the contrary , the first being exposed to the greatest rage and heat of the midday sun in our climate , does not rise above deg . when the second at the same time exceeds little , or not at all deg . the rule of making these , so as they shall keep such a correspondence , is onely obtained by practice , teaching how to proportionate the ball to the cane , and so to adjust the quantity of liquor , as they shall not vary in their motions . the third thermometer . the third is also a copie of the first , but much larger , whence it is more sensible , and swifter near four times ; its length is deg . made like the other two , but as was said before we can lay down no certain rule to make it practice , and often trials being the onely way to effect it , by increasing , and diminishing the size of the ball , or the bore of the cane , or the quality of the liquor , till at length it hits right : and a famous man in this art , who served the most serene grand duke , us'd to say , he could make two or three , or as many as you desired , of deg . which being encompassed with the same ambient , should all agree : but that the case was otherwise in those of . deg . especially of deg . the smallest inequality and error committed , in making one with a large ball , and small neck , being very easie to be discovered : so that they will shew great disagreement and inequality when compared together . the fourth thermometer . this fourth instrument has a spiral canale , yet differs not much from the former ; indeed it comes not near the same scale of proportion , it being impossible to draw so very long a neck equal , and of the same size and bore throughout the whole length ; because there is a necessity to pass and repass it often over the flame to bend it ; whence it cannot be avoided when the metal is softned by the flame , but the cane will be straitned and contracted in some places , and in others relaxed and swelled . blow then a globe of a great capacity , with a very long slender neck , and coyl it round as in the fig. each turn being close to the other , and rising but with a small angle , that the whole height may be as little as possible , and so less subject to be broken to pieces ; then let it have at the top another less ball hollow , and sealed at the flame , to be a receptacle for the air in the cane to retreat to , from the pressure of the water in raising it self , lest for want of room , and being every way closed , it resists the ascent of the water , and so crack the vessel ; after this manner may be had a very ticklish thermometer : and as i may say , of so exquisite a sense , that the least flame of a candle , in an instant shall be able to make the contained spirit of wine move swiftly : which effect will be so much more conspicuous , as the ball is larger , which may be made very capacious at pleasure , without being tied to any rule : this instrument being made rather for fancy and curiosity to see the liquor run the decimals of degrees by the onely impulse of a warm breath , &c. than for any accurate deduction , or infallible proportion of heat , and cold to be learnt thereby . the fifth thermometer . this is more slow and lazy than any of the former , which immediately answer to the least change of the air ; but this is not so nice to move upon a small alteration ; yet since 't is made use of in divers parts of italy , and other places , we will not omit to say something briefly of its make . to make it , you must fill a glass vessel with rectifyed spirits of wine , and immersing a thermometer of deg . therein , place it in snow or ice to cool it ; you must also put into the same liquor many little glass bubbles blown , and hermetically sealed at a lamp ; these by reason of the air contained in them , will keep themselves floating upon the surface of the water ; and if by chance any one being a little heavier in specie than water , shall sink to the bottom ; take it out , and upon a plate of lead , with fine emeril grind off so much of the end as will make it light enough to swim . then the vessel being taken out of the ice , carry it into a room where the air is well heated by a fire , that the liquor which before was very cold , may receive equally on all sides the temperament of heat . so by little and little , as the liquor grows warmer , and by rarefaction lighter , the balls ( which at a more intense degree of cold kept just upon the surface ) shall begin to dive toward the bottom , and at the same time the spirit of wine in the thermometer shall creep up . that bubble or ball thereof which sinks when the thermometer is at deg . shall be reckon'd the first , that is , the heaviest , because it descended when the water was yet very cold , and little , or not at all altered . that which sinks when the thermometer is at . deg . may be accounted the second , at ° . the third , at ° . the fourth , at ° . the fifth , at ° . the sixth , and last , or lightest ; whence it appears , that the bubbles make a scale of equal differences ; that is , from ° . to deg . as likewise , whence this instrument is more gross then the rest , in that it shews by the rising and falling of the bubbles , the alteration of the air ; but to every th . degree of that thermometer which is divided into ° . and to about every th . or th . of that of deg . and to every ° . of that of ° . let these bubbles so tryed and chosen ( and it would do well , if they were of coloured glass , to be the more discernable in the midst of the liquor ) be inclosed in a large cane of glass fill'd with spirit of wine , but not quite to the top , leaving some space for the liquor to rarefie , when the heat of the season shall require it ; and then seal it hermetically . if the heat of the room is not sufficient to make the thermometer rise to , it may be helped , by putting the vessel in a bath of warm water , increasing the heat by gradual pouring in boiling water , if needful ; and so the spirit of wine contained therein will not be more heated in one part than another , but take its temperature as gently and equally as possible . the description of an instrument to discover the difference of moisture in the air. having already treated of those instruments which serve to shew the alterations happening to the air from heat and cold ; we come next to describe another , useful to discover the changes which the air is subject to purely from humidity : and though there may be many and different instruments of this nature , which have been invented by several ingenious persons yet we will describe this one : of which ( since it had its being first in this court ) we will say something out of gratitude concerning its invention and use , though perchance it is wrote of by others . it is part of a cone of cork hollow within , and pitched ; and covered on the outside over with tin : at the smaller end it is inserted into a vessel of glass with a conical point shaped as in the figure , and closed hermetically : the vessel being so made , and placed upon its pedestal , is to be filled with snow , or small beaten ice ; the water whereof as it melts , shall have its issue by the pipe made in the upper part of the glass . the vse of it is this , the subtil moisture carryed about by the air , adheres by little and little to the sides of the vessel , covering it at first but with a dew or mist , till by the coming of more moisture , it gathers into great drops , and at last stealing down the sides of the conical glass drops into a tall cup in the shape of a mum-glass divided into equal deg . and made on purpose to receive it . 't is evident , as the air is more , or less full of moist vapours , the force of the cold condenses a greater or less quantity of water , measured by the graduated glass cilinder . wherefore desiring to compare one air with another ; observe in the first air you would make use of , to what degree the cilindrical glass is filled in a determinate space of time , and then throw away the water , and carry the vessel to the other place , and mark to what degree the condensed water then rises in the same time : and so the difference between the moisture condensed into water at these two experiments being found , gives the true difference between the humidity of the two airs proposed to be compared . we may likewise by exposing this same instrument in the air when the wind blows , find which is the moister , and which the dryer . so we have observed , that when our south winds prevail , the glass sweats excessively , for the air is then very damp , it may be from the south sea , where probably the suns influence being great , exhales those moist particles which afterwards incorporate themselves with the winds ; and in a strong south-west wind , it happened , that from , to drops have fallen in a minute of an hour . one time , the north and south-west wind striving together , the weather being very thick , so that the clouds encompassed the hills , we told drops in the same time : but at last , the north wind getting the better , it gradually gave over sweating ▪ and in little more than half an hour the glass was dry , though there was still a great deal of snow within it : and so it continued all that night , and the next day , while the same winds kept abroad . likewise when the west winds blow , the glass is observed to be very dry . indeed , no certain rule can be given of these things , since they may be altered by so many accidents , not onely from the season of the year , and temperament of the air , but from the nature of the soils and countries themselves , which sometimes alter the criteria of these winds . and we know in some cities and places the south winds are colder than with us , because perchance they may be bounded southward with mountains of snow , the winds passing over which , are chill'd . nevertheless , our instrument remains still unalterably just to every place where 't is made use of , corresponding in all respects exactly enough to the ordinary indications of nature upon these winds . the description of some instruments to measure time. we need not go far to seek an experiment , requiring a true and exact measure of time , such as that by swings , and sounds , or stroaks ; since the foregoing experiment is a sufficient instance , where a comparison is made of the humidity of air , and winds , to find the difference and proportion of moisture which in equal spaces of time distills from divers airs , by means of a glass vessel fill'd with ice : which difference consists sometimes in so small , and scarce perceivable minutie , that the justness of the most acurate clocks cannot discover it , because we either count the time from stroke to stroke , and the ears may possibly be deceived ; or we take it from the spaces shewn by the hand , and then much more easily may the eyes commit an error ; we must therefore of necessity have recourse to an instrument , that may be a more exact time meter , than the sound of four strokes of the clock , or the minutes shewn by the hand can be , in which the judgment of the senses is so subject to mistake . for ( to pass by the errors that may be committed in the dividing of a clock , or other material instruments ) it is very difficult to distinguish , whether the hand is just upon the point marked , or not . and then of sounds , we must when all is done conclude , that the time is already past , before the clock has done striking . wherefore , we take the pendulum or puppet , to be the most exact instrument ; the swing and return of which , being taken for one vibration , we never knew that in the number of many vibrations one failure has happened , ( a thing which seldom succeeds so well in practise ) nor the least variation able to cause an error worth the regulating ; but because the usual pendulum hanging by a single thread in that free liberty of swinging ( whatever is the reason thereof ) in time deviates from its first direction , and towards the end when it approaches rest , its motion is no longer in a vertical arch , but in an oval spiral , in which we cannot distinguish , nor number the vibrations ; wherefore to keep the motion true to the same path , we hang the weight in a double thread , fastning each end thereof by it self at a little distance to an arm of metal , as in the figure . . so the ball or weight being hung on this thread by a small ring or staple , moves in the figure of an isosceles triangle ; for since it hangs free upon the thread , ( though at the first impulse of motion the figure may be rather a scalne ) yet by its weight , it slides down to the lowest part to which it can fall , and keeps it self fixt there : from this triangle it comes , that the motion of the pendulum is regulated , while the threads that make the legs of the triangle ( if we may use that similitude ) serve to stay the ball from swerving more to one hand , than the other , and keep it always directly in the same path. since all experiments wherein the pendulum is made use of , require not the same division of time , a grosser sufficing for some , such as is made by longer vibrations : and others again asking a division so nice , given by vibrations so quick one upon another , that the eye can scarce distinguish them ; to be able with expedition and facility to lengthen or shorten the triangle without every time untying the thread ; let there be added below the upper , another arm of metal also , filled with a square hole on the upright piece of the instrument , so that it may slip up and down upon it , and be fixt at any height by a screw on the back : this arm is cut through the midst , which slit being opened , and closed together by the means of two other screws , stops and holds fast the legs of the greater triangle at any desired space between the ball , and the upper arm , the lower part remaining at liberty ; while that part between the two arms is immovable : by this means the lesser triangle below the stop at the slit which is its base , vibrates freely , and so much the swifter as the ball is suspended shorter , and by consequence the legs of the triangle more contracted . to interpose here a word or two ; experience tells us , ( as galileo has already observed next the observation which he first made , of the very near equality of swings , about the year . ) that not all the vibrations of the pendulum fall precisely in equal spaces , but as they approach nearer to rest , so they dispatch themselves in lesser spaces of time than at first , as may be shewn in its place . wherefore in those experiments that require a greater acuracy , and so long a time of observation , that the little inequalities of these vibrations in a great number of them may at last happen to be sensible , 't was thought good to apply the pendulum to the movement of the clock : a thing which galileo first invented , and his son vincenzio galilei put in practice in . so the pendulum is moved by the force of the spring , or weight , and still carryed to the same height each way , with this great benefit , that not onely the length of the vibrations become exactly equal , but in a manner all the defects in the other parts of the clock are corrected and regulated . that we might be able to make use of such an instrument in several experiments ( which require the time , some more , some less subtilly divided ) we made divers balls of metal fastned to small iron wires , of different lengths , each to be inserted into the same female screw when desired : of these the shortest made its whole vibration , in half a second minute of an hour , the shortest needful ; all other returns of shorter vibrattons being so swift , that the eye is scarce able to follow them . let this suffice concerning those instruments of a more frequent use in the following experim 〈…〉 experiments appertaining to the natural pressure of the air. that famous experiment of the quick-silver is now spread throughout all europe , which first in the year . offered it self to the thoughts of the ingenious torricelli ; nor is the noble and curious inference he makes therefrom less enquired after , and known , when he comes to contemplate the cause of that strange effect ; for he proposeth , that it is the air pressing upon all bodies under it , forces them , and removes them out of their places , when ever there is a void and empty space whereto they may retire , and betake themselves ; and particularly fluids , from their great tendency to motion : whereas solid bodies , as gravel , and sand , &c. or pieces of greater stones ( when there is an endeavour to move them ) are rather joyned , and prest together the closer by that means , from the roughness and irregularity of their parts , so locking the whole mass together , that they sustain and prop up one another , and so resist more powerfully any force applyed to move them : but on the contrary , liquid bodies , it may be from the smoothness or roundness of their particles from some other figure they are of , are easily moved , their parts standing as it were in aequilibrio upon a point , that as soon as ever they are pressed , they yield every way , and spread themselves , as we see water from the least body that falls thereon , breaks away on all sides in orderly circles : and who knows , that from this incoherence and loosness of the parts , it may not happen that 't is seldom or never stable , though in its most proper receptacles , where it seems sometimes stagnant so that the smallest breath of wind curls and agitates it ; and even in standing lakes and pools , where it seems most sedate , though the eye perceives it not , yet there the water is in perpetual motion , and obedient to all the undulations of the air , which it may be is never at rest ; nor is this more peculiar to water than any other liquid ; in all which , as some think , the force of the airs pressure is very evident ; especially , when they are in a place which in any one part of its superficies has a vacuum , or as it were void space into which the liquid may retire : for the contiguous air pressing the fluid on the one part with so many miles height , when on the other part ( contiguous to the vacuity ) it touches not , nor can gravitate at all ; it must necessarily mount it into that void space , till the raised fluid becomes an equipoize to the airs pressure on the other part . this equilibrium with divers fluids , is at divers heights , as they are more or less heavy in specie ; a lesser or greater quantity of which is able to resist the force and weight of the air. we ( following the common practice , as likewise the first inventer torricelli ) make use of quick-silver , which being very heavy , is much more commodious for the experiment , making a vacuum in a far less space than any other liquid can . what is needful to be seen in this matter , the following experiments will manifest . an experiment , suggesting to torricelli the first inventor thereof , that it might be the natural external pressure of the air which sustains the mercury , or any other fluid , at a determinate height in the empty space of a cane , &c. tab. . p. . the space af shall contain no air , which is manifest by inclining the cane about the point c as a center , when you will find the internal level f successively move towards a , but never rise above the horisontal prickt line fg , drawn from the point f , the first height of the quick-silver , when the cane was perpendicular ; and if the end a be inclined quite to the line fg , the cane will be full of quick-silver , except a very little at a , whither still above the level of the included mercury , gathers together either some air wherewith perhaps it is impregnated , or some other invisible effluvia exhaling there from . this is most conspicuous , when a small quantity of water is in the cane , which in making the vacuum gets above the mercury , and discovers in their passage through the midst of it , that several small bubbles rise out of the mercury towards the empty space ; as may be shewn hereafter . this vacuity of air may likewise be proved by water poured upon the quick-silver in the vessel de. for lifting the mouth of the cane c out of the quick-silver , as soon as it is every way encompassed with the water , the mercury will fall down , raising the water in its place to the top of the cane ; provided it exceeds not the length of feet inches , to which ( as may be elsewhere discoursed ) it is usual for water to be sustained ; probably from the same power that bears up the mercury to / inches ; and indeed , there will be no great quantity of air at the top of the cane ; since there is onely some thin effluvia forced into an almost invisible space , which ( as we said ) rise from the quick-silver , or is some other subtil matter capable of penetrating thither . upon this ground we shall call ( as before for brevity-sake ) the space af , ( and any other left by the subsiding mercury in a like vessel ) the vacuum , or void space , ( i. e. ) empty , and void of air ; at least such as unaltered , and in its natural state encompasses the cane ; not presuming here to exclude fire , light , or the ether , or any other very thin bodies , which are either in part dispersed with little vacuities interposed , or wholly fill●d the space , which we call the vacuum , being stretcht and attenuated as some think . nevertheless , 't is our intent in this place , onely to discourse of the space fill'd with mercury , and endeavour to find the true cause of that wonderful counterpoise of this weight , without entering into any dispute with the deniers of a vacuity . and since many experiments have been made for this end , ( as well what is related by others , as what has been invented by our academy ) the success shall be faithfully set down ; our custome being always to deliver the matter historically , and not to defraud the inventors either of their invention , or due praise . an experiment of mr. robervals in favour of the airs pressure upon inferior bodies , tryed in our academy . let there be a glass vessel a , to the bottom of which bc perforated at d ; let the cane de inches long be affixt , over this hole set the square glass f , then close the vessel a with the glass cover gh , having an open nose hi , and a hole at g , through which let the cane ki be put open at each end , and about inches long , or not less then ; let this down into the glass f , but not quite to touch the bottom ; and fasten it there with mastic , or other cement at the fire , to the hole in the cover g ; this cement , or paste , is made of brick reduced to an impalpable powder , and incorporated with turpentine , and greek pitch ; 't is admirable to stop glasses to exclude the air ; let it be luted close with the same , round about where the said cover and vessel joyn ; and cover the lower mouth e with a bladder : then pour in at the upper end k so much mercury , till running over the glass f it falls upon the bottom bc , and thence by the hole d fills the lower cane ed , and after that the whole vessel a , the air having its way out by the open nose hi , which when the mercury begins to run through it , close well with the bladder i , and lift up the whole cane to k till a little runs over , that not the least air may remain when closed , which do with the bladder k. lastly , open the other bladder at the mouth e under the superficies of the stagnant mercury mn , into which the cane is immersed , and immediately the upper cane kl , and the vessel a will empty themselves ; the glass f and op , part of the cane de being about ½ inches above the level , mn remaining full . this done , the ingress of the external air upon opening , or pricking the bladder i , will immediately suppress the cilinder of mercury op into the lower vessel , and raise up another qr from the mercury in the glass cup f into the cane lk equal to the former op , and therefore ½ inches long ; and this cilinder will not subside until the external air entring at the top k , rushes in upon it through the cane lk . if in this vessel a , a little bladder be enclosed , taken carefully out of a fish , the air that is naturally therein being first expressed , so as very little be left in the folds thereof , and then the orifice well tyed together , as soon as ever ( by the subsiding of the mercury ) the bladder shall be in vacuo , that little air remaining in it will swell , and distend it ; nor will it shrink again , 'till by opening the vessel at k the external air gets in to press upon it . but we have observed more clearly the like expansion of air in vacuo , in a vessel made after another manner , as adb , wherein a lambs bladder squeezed together , and almost wholly discharged of air , is inclosed thus ; fill the vessel with quick silver by the mouth d , and tye it over with a bladder , the lower mouth e being before stopt with the finger , then immersing it into the quick-silver , in the vessel fg , open the mouth e , and let the quick silver subside ; then will the bladder c hung by a thread in the empty vessel adb swell it self , and so continue , till by opening the mouth d , the external air enters a the top , which at the same time will bear down the cilinder of mercury into the vessel at the bottom fg , and press together the bladder . likewise , if in closing the mouth d , there be put upon the mercury a little froth made with whites of eggs , or soap-suds , still as the vessel adb empties it self , the air imprisoned in these small bubbles will so swell them , that at length breaking through its thin confinements , it shall be at liberty , and quite released from the liquor , which will fall down upon the mercury like dew separated from that fine steame of air contained in the froth . tab. p. . experiments alledged by some against the pressure of the air , and the answer thereto . there have been two experiments , from which some of our academy judged a considerable argument might be raised against the pressure of the air upon inferior bodies , and the effect of sustaining fluids attributed to something else . one was , by covering the vessel a , and likewise the cane with a great bell of glass bcd pasted down close to a table round the edges : for then they imagine , that if it were true , that the weight of the whole incumbent atmosphere of air did protrude the mercury into the cane , and counterpoise it with its weight ; by defending ( with this cover of glass ) the stagnant mercury from so great a pressure , the small , and scarce sensible weight of the little portion of air included within the bell , must of necessity be unable to keep the quick-silver at the same height whereto the momentum of so vast a space of air had raised it ; but notwithstanding this , they never observed it to subside a jot from the usual height eg . the second experiment was of the same nature , but more artificial . we fill'd with mercury a small vessel ab ( which at first was made without the beak cd , added afterwards for another experiment ) and plunged into it when full , the cane ef , and making the usual vacuum , there was poured out from the vessel ab a small quantity of quick silver , so that a little air might be in the space ah to bear upon the stagnant level hg , and then the weight and pressure of the external air was kept off , by closing carefully with the afore-named cement , the round space a between the neck of the vessel , and the cane ; and yet in this case , when the bulk of the external air was so lessened to nothing almost , we saw no sensible abatement of the mercurial cilinder if below the usual height . but the assertors of the airs pressure answer these experiments thus . that these events on the contrary greatly favour their opinion ; for the immediate cause ( as they say ) that forces , and powerfully sustains the mercury , to the height of / ● inches , is not the weight of the incumbent air ; which indeed is taken off by the bell in the first experiment , and by the cement in the second , but is in reality an effect of compression , which was produced and wrought in the air ( contained in bcd fig. . and in ah fig. . ) by that weight before they were cemented close : whence 't is no wonder , that the quick silver subsides not from its usual height , the air keeping in the same state of compression as 't is forced to do , from the resistance made by the glass bell , and cement , which supplies the place of all that vast tract of incumbent air. and because 't is yet believed by some , that the force of a supposed spring in the air acts wholly in this effect , so as without it by no means it could happen ; 't was therefore attempted to insinuate the contrary , by the following experiment . taking the same vessel ab , with its cane ef ( before we poured off any of the mercury , as was directed in the former experiment , or stopt up the mouth of the vessel at a with cement ) and then setting all in a great vessel full of water klmn , the quick-silver was observed to be sensibly deprest from a to gh ; and on the contrary , raised in the cane from i to o ; this ascent being about the fourteenth part of the whole height of the water ef : then the mouth a was closed , that so onely the water in the space agh might press upon the mercury , which nevertheless lost none of the height lately gained by the weight of all the incumbent water ef , above the first level i ; yet in this case the included water agh , not by vertue of any springs ( which perchance it had not ) but because it had been forced by the charge of the whole height ef into the space left by the quick-silver rising from i to o , and kept there by the same force , and so hindred from returning . the same may be said to happen to the air. lastly , some desirous to see what effect a greater , or lesser rarefaction of the air included in agh would have , made this trial. joyning to the vessel ab the beak cd ( into which they fastned a mouth of metal with a female screw ) , they adapted a syringe ; then whenever a suction was made of the air in agh , and so what remained attenuated and weakned , the level i , might be seen to subside , contrarily when compressed more , by forcing in new air ; the same level i was raised . the same happens from fire or ice approaching it ; for the mouth c being closed , when fire is externally applyed to the air in agh , the mercury rises , and by the application of ice subsides ; as if after the same manner , as it happened in the contrary operations of the syringe ; the air had been condensed , and enforced by heat , and rarefied and weakned by cold ; from all which matters it seemed probable , that this sustention of the fluid does not absolutely depend upon the weight of the air , but also upon the compression which lower parts of the air receive from those above . an experiment to know if the air near the superficies of the earth , is pressed by the weight of the air above , and if it be put in a void space at its liberty ; whether it will expand it self to a greater space , and how much when yet it is still unaltered by any new degree of heat . the ingenious observation made by m. roberval with the little bladder of air enlarging it self in vacuo , moved some to believe , it might be determined how far the air is capable of expansion when at absolute liberty in any place ; for it seemed probable to them , that in any vessel proposed , a void space might be assigned sufficient for the whole increase of such a quantity of air ; whence whatever should happen to exceed that quantity ( requiring a more ample space to dilate it self in ) must proportionably more , or less depress the mercurial cilinder below the usual height of about inches : and on the other side , what ever comes short of it , will easily permit the mercury to rise to the usual height . the experiment is thus , let there be a vessel of glass abc , with a shank bc about inches long , open at g ; and let there be a tall glass provided , def fill'd with mercury to immerse the shank bc into , but such a vessel as may not onely serve to immerse it into , but capable when desired of receiving either all , or a great part of the shank into it self as a scabbard . let there be another vessel ghi equal in all respects , as near as may be to the former abc , in which make the usual vacuum , marking the height to which the mercury is sustained at that time , kl ; then fill with mercury the vessel abc fig. . being as was said of the same size by the mouth c up to m , and let mc remain fill'd with air. it is clear , that stopping with your finger the mouth c , and inverting the vessel , the small quantity of air left mc will pass through the mercury , and take its place in a. then plunge the mouth c beneath the level of the stagnant mercury df , and removing your finger make the vacuum pa. the height of the mercurial standard will be pq , measure it , and if it be found equal to lk in the vessel ghi fig. . in which no air was left to alter it , it shews that the cilinder of quick-silver pq is not in the least influenced by that little air remaining mc , because the space left empty from a to p is more than sufficient for its utmost expansion ▪ proceed then gradually to depress the cane , or shank bc into the mercury df , that the level p may be gradually raised also , suppose to r , successively lessening the space pba left for the air ; continue this depression as long as the height qr shall be found equal to kl . and note that r is the fixt and utmost bounds of the whole height of a cilinder of mercury equal to kl , all the subsequent heights towards b ( caused by a farther depression of the cane into the vessel de ) being successively diminished : whence 't is probable , that the void space abr is quite filled by the expanded air ; because from r upwards , the mercurial cilinder suffers some force from within : an evident sign ( as some think ) that the quantity of air mc will not be contented with a less space , than abr for its full , and free expansion ; the measure of this space abr , and by consequence of the expansion of the air mc , is thus obtained . all things being as in the vessel abc , where the air mc has its utmost dilatation in the space ar ; then seek the proportion between the space mc fill'd with air naturally comprest , and the space ar fill'd by the same air dilated , which is found at one trial by weighing the water that may be contained in the space mc , and likwise that which may be contained in ar ; as suppose they are found in proportion to each other , as to , we may affirm the same of the air , that ( when at its greatest expansion it takes up times a larger space , than when in the state of its natural compression . note , that having often reiterated this experiment , and at divers seasons it has not always succeeded in the same proportion : for when at first we made it with another kind of apparatus , though the operation was much the same , yet the proportion was as to . afterwards making use of the present instrument we found it as to ; lastly , the third time ( which also seemed to be more exactly performed than before ) it was ( as is set down ) as to ; nor is this diversity strange , considering that the experiment can never be made with the same air , but still either more or less comprest , as the season is warmer or colder , and as the place of observation is higher or lower , whence 't is impossible it should be dilated in the same manner , or in the same fixt and unaltered analogy . note also , that the ball gh was joyned to the cane hi , because if any invisible particles of air were disseminated through the mercury , they might rise into the ball , and have room enough to expatiate in without being able by their pressure to alter the natural height kl raised by the equipondium of the air. an experiment , proposed to shew , that where the pressure of the air is taken off , the mercury is no longer sustained . having chosen a small cane of glass ab not so long as the mercurial standard , close it s lower mouth b with a tab. . p. . bladder , fill it at a with mercury , and put into it a little dart ca , the one end gently touching the bladder tyed at the bottom of the cane , and the other a little above the mouth a ; which also close with a bladder . let there be another cane de ▪ longer than inches , the mercurial standard , made so that the mouth thereof e may be easily covered with the finger , and the end d large enough to receive the cane ab , which already fill'd with quick-silver must be put therein , observing to let it down so low , that its end b may be less than / inches from the superficies of the stagnant mercury fg , reckoning towards d ; then fasten , and close stop the two canes together at d with cement , that the external air be perfectly excluded . after this at e fill the whole cane ed with mercury , and stopping it at e with the finger , invert it into the stagnant mercury fg , and make the vacuum in the upper part dh , that the mouth b may still remain immersed in the quick silver hi ; close again the mouth e with your finger , yet not raising it out of the mercury fg ; whence the communication between the quick-silver fg , and that in the cane de being hindred by the finger , the cane de will be as a vessel , into which the little cane ab is immersed : then striking the end of the little dart ac , thrust off the bladder from the bottom b ; as soon as 't is opened , the mercury will all run out of the cane ab , ( although 't is shorter than the mercurial standard , and its mouth b still in the mercury hi ) contrary to what would have happened , if the space dh now void , had been full of air : as the following experiment will manifest . an experiment likewise proposed , to try if ( when the pressure of the air is taken of ) the sustained fluids will subside , and upon its return be raised again . let the cane ab be about foot inches long , and hermetically sealed at a ; let the beak ac be drawn so slender , that it may be easily nipt off with the fingers , and with as little trouble sealed again with the flame of a candle : fill the cane with quick silver at the mouth b , which ( as also the mouths of all canes and vessels employed in making a vacuum ) ought to be ground , and rubb'd smooth ; so to be more securely stopt with a finger . then let there be another cane de made of the length of the first ab , and seal it at one end , but let it be open at the other , not with a round mouth as the former , but cut a slope ; this when fill'd with mercury , is to be put like a sword into its scabbard into the cane ab , made large enough to receive it . then the mouth b being stopt with the finger , invert both the canes , and plunge them into the mercury in the vessel fg , making the vacuum as is usual ; which will be at the same height in both canes , levelling the mercury in the innermost and outermost two at h ; then with the finger stop the mouth b of the exterior cane , while 't is yet beneath the superficies of the mercury fg ; so that the mercurial cilinder bh may have no farther communication with the mercury in the vessel fg. but the exterior cane will be a vessel to contain the inner cane de , as in the former experiment ; and the mouth of the inner cane e , will by reason of its oblique figure , remain open : this done , nip off the end of the beak c , that the air entering thereat upon the quick silver h in the exterior cane , encompassing the other , and pressing thereon , may immediately fill the innermost cane de ; which it will do , provided that in the cane ab there is enough quick-silver to fill it ; and the space from a to h , which is the vacuum , exceeds not inches this experiment is easily made , and repeated in a short time . an experiment , proposed for the same end , to know if the air acts in the sustention of fluids . let there be a little glass vial as abc , whereof the mouth c is drawn so small , that being filled with any liquor , and turned downward , though open at c , yet it will not run out ; fill this with mercury with a small glass funnel , and stop it at c with wax , or mastick , then place it in the glass vessel de , so that the mouth thereof c may rest upon it , and the cover f be closed with the usual cement ; then fill by the mouth g , the whole vessel de with mercury , and make the vacuum ; which done , apply a candle ( on the outside of the vessel de ) to the mouth of the vial c , and so melt off the wax : as soon as ever 't is open , the little vial will begin to run , and empty it self of the mercury ; but upon admission of air into the vessel de , it will immediately stop . if instead of mercury the vial be filled with oile , or wine , or any other liquor , the effect will be the same . an experiment to shew , that in any vessel above / inches long , fill'd with mercury , provided it has a very small mouth , when it is inverted in the open air , a vacuum will be made in all that space which is above the height of / inches . take a glass cane ab of what size and length you please , above / inches , seal it at a , and let it be open at b , with a very small orifice ; fill it with mercury , and hang it in the open air perpendicular , with the end b downwards , the mercury will presently run out , ( not by drops , but ) in a continued stream till it subside to c , the usual height of about / inches , and then it will stop of it self . an experiment to shew more evidently , that where the pressure of the air is wanting , the bearing up of the fluid is lessened in a cane of any length ; and upon the return of the same pressure , raised up again . tab p note that kl is about the fourteenth part of the whole height of the water ml ( for what cause may be told presently ) but when it does exceed it , ( as it may sometimes happen ) 't is from two causes ; first , either the water wherewith the vessel is fill'd , was not poured in so hot , that the vacuum left by it , in condensing , is capable of receiving all the quick silver falling from the cane ef ; for when the space ai left by the condensing water , is fill'd by the subsiding mercury ( which falling into the vessel gb raises all the water ) there can no more mercury descend out of the cane ef , and so it will be above / of the height ml . or secondly , the other cause may be , when this void space ai is indeed sufficient for the mercury in the cane , but not for the air ; which may rise either from the mercury in the ball , or from the water in the vessel , which air requiring a larger field to expatiate in the● the void ai , may possibly make some impression upon the superficies of the water , and so communicate it to the cane , and bear up the mercury a little higher than the bare weight and pressure of the water would have sustained it at . an experiment from whence is shewn , the efficacy which the pressure of another fluid joyned with the air , has upon the sustained mercurial cilinder . the vacuum being made with the cane abc , wherein the simple pressure of the air raises the mercury to d , the usual height of / inches , pour water upon the stagnant level eb , and fill it up to a , and you shall see the level d raised to f , and the space fd will be / of the water ab poured in : and that because , to the weight of the cilinder of mercury df , the weight of the other cilinder of water will upon trial be found equal , having the same basis , and of the height of ab . but if instead of water the same space ab be fill'd with oyl , the mercury will rise to g onely ; if with spirit of wine to h ; whence we may ( from the proportion of the height of the fluid ab encompassing the cane , to the height of the increase caused by that fluid in the mercurial cilinder above the first height of / inches caused by the air ) find the proportion of specifick gravity between the mercury and any of the ambient fluids . and likewise as easily that of the specifick gravities of the fluids , in respect of each other . the same may also be obtained without a vacuum with a plain cilindrical glass ab in the former fig. into which by putting a little mercury , and the small cane ac ( now supposed open at each end ) and then pouring an equal quantity of several fluids , seperatim upon the superficies of the mercury eb , and all to the same height , suppose a ; from the different heights of the mercury in the little cane fg , hd , caused by their respective gravities , we may not onely have the proportion of their specifick gravity with the mercury , but also that of the fluids compared with one another . note , that ( in this , and all like experiments ) where it happens that the inward or outward level of the mercury is altered by the pressure of some fluid , or otherways , then the letters pointing at those operations in the figures , are supposed to be removed to the places requisite , and successively follow the level , as it gradually moves from place to place . an experiment shewing , that where the air presses not at all , a vacuum may be made not onely with mercury , but also with water , to any height of the tube , provided less than that whereto it used to be sustained by it . let there be a glass vessel ab containing about l. of water and the mouth a big enough to receive the cane cd / inches long sealed at c , but obliquely open at d : this cane must have at a , ( the place whereto 't is let down into the vessel ab ) two small anulets of glass close together , that the bladder with a hole therein may be tyed very fast between those two rugs : then fill the whole vessel ab with water as hot as possible , and the cane cd with cold , put upon it at the lower end d the plate of glass e fitted to shut the mouth of the vessel ab : immerse the cane therein , turn down the bladder , gather it together , and bind it close about the neck of the vessel , having first prest out the air from its folds . now as the water cools , part of the vessel fg will be empty , and likewise ( as in the former experiment ) part of the cane ch , where the water will rest , nor move but upon some alteration of the external heat , and cold ; but upon pricking the bladder , the air forcibly entring upon the level of the water in the vessel , will refill the cane as at first . it was thought by some , that the water in the cane does not fall at first when the vacuum is made to the same level with that in the vessel , ( supposing the space ag capable of receiving it ) it may be from a cause mentioned in a foregoing experiment ( i. e. ) from some air which raises it self from the water into the void space , perhaps too narrow for its full expansion : whence they imagine , that if the experiment were made with wine , oyl , spirit of wine , and other liquors , from a greater or lesser vacuum remaining in the cane , it might be determined which of the fluids has most air dispersed through its particles . an experiment first made in france , and after by our academy ; whence 't is probable , a more cogent argument for the pressure of the air may be drawn . m. pecquet in his book of new anatomical experiments , writes , that it has been observed by many , that the height of the mercurial cilinder in vacuo , varies according to the places where the experiment is made ; whence in higher places 't is less ; and in lower places , and deep pits , greater : provided the height be pretty considerable , as that of the highest mountain of auvergne , at the top whereof the mercury wants much of the usual height : which has been said to happen , because the higher air which is found upon the tops of vast mountains , having a lesser weight upon it , makes a more faint pressure , nor is able to raise the mercury to that height whereto the lower air of valleys and plains easily mounts it . howsoever , the truth of this assigned cause may prove , of which 't is not at present our intent to discourse ; yet we have observed the very same effect on the highest tower at florence , which is foot high : as likewise on divers of those small hills which surround the city : and we find it manifest , that the height of the mercury varies in different parts of the tower , or hill , subsiding as we ascend towards the top ; and as we descend lower , and lower , it gradually rises , till being brought into the plain , it ballances it self at the usual station . but to make this effect sensible , at least foot is requisite this observation has given some ground to hope , this instrument might be improved to shew and determine exactly the state of the airs compression ; believing that the divers heights of the mercurial cilinder ought infallibly to shew the various pressures of the air upon the stagnant mercury , upon account of the different height of the atmosphere above the said level . but from the many inequalities , and irregular movements , which in a long series of observations we have taken notice of , this thought is rendred dubious ; for this instrument being let alone fixt and unmoved in any place , its variations were very small , and seldom above or degrees , which came onely from the different temperament of heat and cold ; and on the contrary , very notable variations to above degrees have sometimes happened from other reasons to us unknown and hid . nevertheless , to arrive at this knowledge by other means , more certainly and assuredly , we thought of making the next following instruments , whereon though the external accidents of heat , and cold have some effect , altering them from their true and simple operation : yet these disadvantages are not so insuperable , but the accuracy and care of the diligent observer may easily avoid them . tab. . p. the descriptions of the instruments : shewing , the various alterations happening in the state of the natural compression of the air. the first instrument . chuse out the smoothest and evenest glass cane you can , being somewhat larger than an ordinary goose-quill , which must be bent in the figure of abcd , with its two arms ab , cd parallel , and very near of the same length , as is represented in the figure ; this must be acurately divided into equal degrees , so that the decimal marks upon each arm , may be upon the same level : which to do more easily with the small buttons of enamel , you may glew on the out-side of the arms two lists of parchment , equally divided ; which through the transparent glass cane will readily point at the place where the buttons ought to be fixt . the arm cd is to be widened like a trumpet at d , and the other arm is to be joyned to one , or more glass balls , as e , f , which are empty , and capable of containing some quantity of air ; the last of which must have a beak gh drawn small to be sealed with a flame , as occasion requires : then pour in some quick silver at the mouth d , which ( the vessel being open at each end , and the two arms of an equal size ) will stand both ways , at an exact level , as i , k. the instrument , being so prepared , is to be carried to the foot of some tower , where let it rest 'till the air contained within the balls , may be of the same temperament with the ambient : then presently seal it with a flame at h , but be sure to be very quick in doing it , lest the included air should alter by heat of the flame . this done , let there be one upon the tower , to draw up the instrument with a pack-thread ( fastned to the upper part thereof , so as not to invert the beak ; ) and when at the highest part of the tower , let it stand upon a plain , as at the foot thereof it rested ; then examining the temperature of the air above , and finding it the same with that below ; you may perceive , that whereas at the foot of the tower , the quick-silver rested at i , k ; at the top of the tower the level i will be sensibly deprest , as to l , and the level k in the same proportion raised for the space mk : caused , as they say , by the more vigorous pressure which the lower air makes upon that included in the balls e , f , in comparison of that above ; by which the level k is more lightly press'd . remember , that every little difference of heat and cold between the air above , and thar below , is able to cause a variation in the levels of the two arms ab , cd ; and so alter what should have happened from the diversity of pressures made by the air : wherefore this instrument is a sort of thermometer for the air ; and that , for the most part , very nice . therefore in the making this experiment , chuse the dawn of the day before the sun is up , or any other close season ; that the air above and below may be of an equal temper , as near as possible ; nor let the time between the observation made at the bottom and top of the tower be long ; take care also not to stand too near the instrument , when you observe the degrees , which should be done quickly , and be sure not to breathe upon it , lest it heat the balls : which should be of as thick glass as may be , to defend the better from any external impressions , the air contained in them . all this diligence must likewise be used in the management of the three following instruments , they being not at all less nice , and subject to cause the same mistakes as this first . the second instrument . let there be a vessel of glass ab containing about two quarts , with its beak cd open ; pour into it so much mercury as will cover the mouth e of a small cane ef ½ inches long , and open at both ends , but cut slopeing at e , and round at f ; which being divided into equal parts , or degrees , is to be immersed into the stagnant mercury gh ; and the space left round the mouth of the vessel a is to be closed with cement to shut out the air ; being so made , carry it to the foot of a tower , and let the internal air be reduced to the same temperament with the external ; immediately seal it , and let it be drawn up to the top of the tower ; where having placed it on a plain , you will find the mercury somewhat raised within the cane , suppose to i : which rise , ( they say ) follows also from the same reason which we gave in the description of the former instrument , viz. the lower air , such as is included in the space acgh , has a greater force and power upon the level of the mercury encompassing the cane , than the higher air has , which presses upon the level i , entring in at the mouth of the cane f , so that it raises the little cilinder ik , to make a just equilibrium between those two momentums , or powers . the third instrument . blow a glass ball a / inches in diameter , with its neck bc about / inches long , divided into very minute degrees , pour into the ball so much water as will fill half the neck , which is the space cd : stop the mouth c with a finger , and plunge it into the water in the bladder ef , which is kept from being fill'd to its whole spherical capacity , by means of a weight at pleasure hung at f : close then the folds of the bladder , and bind it very strait round the neck bc , at e , taking care when you bind it , to pour in water till it runs over ; so to be secure that no air is included , which might any way alter or spoil the due and right operation of the instrument ; every thing being performed after this manner , at the foot of a tower , fasten to the ball at g , a string let down from the top of the tower ; and having observed the degrees whereat the water stands , let it be drawn up : when again observing , it will be found deprest some degrees lower , as to h , which will be more or less according to the present state of the air ; and the greater or lesser height of the tower. this also they say happens , for as much as the bladder ef is encompassed with the air of the higher region ; and so not sufficiently armed externally to resist the force made on it by the air of the lower region ( which is included in the space gd ) in dilating it self ; whence it must necessarily yield to enlarge its internal capacity , which the small bulk of water dh sinks down to fill out . tab. . p the fourth instrument . cause a glass ball to be made a , with its neck bc like the third instrument , onely it must have an open beak drawn very slender d , round the mouth of the neck c bind the bladder ef very close : this bladder is to have in its lower ligature f a small thread of glass , or brass-wire , which passing through the bladder is to enter into the neck of the ball bc , and so point at the degrees it is minutely divided into : let this instrument be carried to the foot of the tower , seal it as the other at d , and take notice of the degree pointed at by the end , or dart g : raise it then to the top of the tower , and you will find the dart higher than before , by some degrees . to give the reason of this effect , they consider , that the vessel is filled with air of the same temperament with that below , which as it finds one part of the vessel less solid than the glass , yielding , and easie to be distended , such as is the bladder ef , so it no sooner perceives it self relaxed from the prison of the surrounding air , by being raised to a higher place ; but it immediately endeavours to enlarge it self , and be at liberty ; which it effects , by swelling the bladder a little more : now whilst this by being so puffed up comes nearer to a spherical figure , the transverse diameter of the ellipsis ef is shortned , as the bottom f is gradually raised , when also the index fg fastned thereunto , by obeying its motion , rises higher in the neck bc , and so comes to point at a higher degree than g. various experiments made in vacuo . from the series of the afore-mentioned experiments , torricelli's thought touching the airs pressure upon all inferior bodies , seems fully confirmed . and tho it may be a daring undertaking , and full of hazard , to determine of the causes where geometry gives no illumination ; yet this boldness is never more excusable , nor the danger more like to be avoided , than when our understanding , onely by a path of many , and all agreeing experiments , makes toward the attainment of its desire ; which tho it may sometimes fail off , yet it is satisfied in approaching as near as may be towards it . since then it appears from the effects already mentioned , that we have gained some reasonable probability of such a pressure ; it was judged not altogether a fruitless labour , to proceed to make divers experiments in vacuo : and observe , whether the manner of their operation would succeed contrary , or any way different to what they appear , when environed on every side with the free air. experiments to know whether small drops of liquid bodies , being freed from the airs pressure encompassing them , lose the spherical figure they naturally are off . some have attributed to the pressure of the air , that generally known observation of the drops of mercury , tab. . p. . or any other fluid ; which spurted , or raining through the air , or let fall upon any dry , or dusty body , always are nearly of a globular figure : wherefore they were willing to try it in vacuo , imagining there might then happen some notable variation . but experience it self shewed , that the effect proceeded from some other cause , than the airs pressure ; for having made the vacuum in the vessel ab , the cavity a being quite void , by turning the stop-cock there was let fall some drops of water , or mercury out of the ball c upon some colewort-leaves included in the ball a , ( which had some drops of dew hanging on them , with which they were gathered ; ) these drops that were admitted , contracted themselves as round , as if they had been upon a growing plant. so when the air in the vessel a was condensed , or rarefied by means of a syringe cb ; the drops of water , or mercury , sprinkled upon the bottom of the vessel were not altered from their usual shape . an experiment , shewing the effect of heat and cold , applyed externally to the void space . bind the bladder abc under the ball d , make the vacuum therein , turn the bladder upwards to be tyed there likewise ; then with a cane of glass , or any thing else that will not alter , or bend , take the exact height of the mercurial cilinder hg , from the stagnant mercury ef : after this , fill the bladder with hot water , and soon after measuring , you will find the cilinder a little depress'd below the former height . this observation made , throw out the hot water , let it stand till it returns to the former height h , and then fill the bladder with cold water mixt with beaten ice , and salt , and in a little while measuring ( as before ) you will observe the cilinder notably raised . nor will we omit , that the hot water made use of in this experiment raised a thermometer of deg . to ° . and with the same heat shortned the mercurial cilinder one th part of the whole height . and that the cold water increased to one th part , when in the same water the thermometer came to deg . ● / . if then a little air be admitted into the ball d , this because it becomes very thin , by reason of the dilatation it has in the void space ; quickly imbibes heat or cold , and by its rarefaction , or condensation causes that the alterations in the rise , or fall of the mercury are much more sensible , and swift . an experiment to manifest whether the air be that which serving as a foile to the lower superficies of a lens of glass , reflects that second image inverted more dimly and faintly which we see of a flame , or any other object visible there , as kepler thinks it is . on the mouth of the glass vessel ac we cemented with hard cement a glass lens ab : this mouth had its lips turned a little outward , and made smooth for the more easie fastning on of the lens ; then filling the vessel with mercury , we made the vacuum ; and inclining the tube we tyed it to the rest , as in the figure ; and having made the room dark , and bringing a candle near it , we observed in the lens , the two images of the object , as is usual : one of these was lesser , but very vivid , and always direct ; which was reflected from the convex outward superficies . the other was indeed larger , but more obscure and languid , and inverted , which nevertheless was not lost , though the imagined foil of air was wanting ( on the concave inward superficies of the lens ) by reason of the vacuum made . in making this experiment , we always us'd to put three or four fingers depth of spirit of wine upon the mercury , that when the vessel was inverted to make the vacuum , the spirit getting uppermost might wash , and cleanse the lens from all foulness left there by the mercury , lest that should give some occasion to imagine it might serve instead of the foil of air. but nevertheless ( as we said ) the appearance of the two images was the very same ; and when we permitted the air to fill the void space , it gave not the least difference . an experiment , to know whether amber , or other electrick bodies require the medium of air to make them attract . prepare a vessel of thick glass , big enough to stir , and turn the hand within the upper part thereof ab . let it have three mouths a , c , and de ; let a be open closed ▪ c with a bladder , and rest it upon a little bundle of cotton , or some soft cushion floating upon the mercury in the basin fg , that so the great weight of mercury to be poured in may not burst the ligature , or break the cane . the mouth de made large enough to receive a mans hand , must have an edge , or lip of glass round it , about which must be tyed very close and fast a large bladder open each way , as de , hi , through this the hand is to be put into the vessel , with a small piece of the best yellow amber , having first placed in the vessel a little light bit of paper , or straw where the amber may readily approach it , when it has been rubbed , and heated upon a piece of cloath k , fixed for that purpose within the glass : then bind the other side of the bladder hi , round the wrist , a little above the pulse , that so the hand may move freely in the vessel ; and let the place where the ligature is made , be armed with a ring of leather bound fast to the skin of the arm , upon which ligature the bladder may be cemented to the arm , which done , fill by the mouth a , and the vessel with mercury , taking care in filling it , that the folds and wrinkles of the bladder be all filled with mercury , that as little air be left as is possible ; when quite filled , close also the mouth a with a bladder , and untying the lower ligature c , beneath the stagnant level fg , let the mercury fall to make the vacuum . then holding the amber between your fingers , rub it strongly upon the cloath k , and present it to the paper or straw ; and observe whether it attracts it , as it do's in the air. tab. . p. . yet still desiring some fruit of this experiment , we thought of making another vessel , as abc : perswading our selves , that therewith we might more easily obviate the inconvenience of the airs entring , and also the difficulty of moving the wooden instrument forward and backward . wherefore , filling at the mouth a , this vessel , having first closed its other mouth c , and rested it as in the former experiment upon the cushion as was directed ; we then bound the bladder abc about the piece of wood , and thrust it into the mercury , so as the end thereof , whereto the amber was fastened , might reach a piece of cloath stuck to the side of the glass . then we threw in some small bits of straw , and turning down the bladder , we bound it fast down the neck a , the vacuum made , by moving the wood or handle which stood out we rubb'd the amber upon the cloath , and when we thought it might be hot , we apply'd it to several pieces of straw , which in the descent of the mercury stayed to the sides of the glass ; but we could never perceive that any were attracted by the amber ▪ but note , that this experiment is not to be much accounted of , nor the effect to be attributed absolutely to the want of air ; for in such a vessel at least a small quantity always gets admission ; nor could we ever so bind the ligature , but by some unseen ways it deceived us , which it may be happened from the motion required in this experiment to heat the amber ; so that we may almost judge it impossible , but the ligature must be relaxed ; at least , so much as is needful to let in the subtil air. 't was observed also , that when the vessel was full of air , though we rubbed the amber with great force upon the piece of cloath b , yet it had no attraction ; a thing which at first made us suspect that some dregs of the mercury adhered to the cloath , whence the amber by rubbing might acquire some foulness to close and stop up the imperceptible pores of those passages by which the attractive virtue issues out ; which suspition seem'd more probable , because we already knew some liquors wherewith the amber being wetted ( or any other electric substance ) refuses to attract . but since we after found , that the same amber rubbed upon a piece of cloath often dipped in mercury , did nevertheless draw with great force , we thought the humidity of the gum ( made use of to fasten it to the glass , being imbibed by the cloath ) might impede the effect : we therefore sealed a piece of shamois instead of cloath , with wax to the side of the glass , that all manner of suspition of any wet soaked up , might be avoided . nevertheless , all this diligence was in vain , for whether the vessel were full , or empty of air , the amber attracted not , which is all we can with truth report of an experiment attempted so many ways unsuccessfully . an experiment examining what may be the motion of the invisible effluvia of fire in vacuo . being already satisfied by many experiments , that the heat of fire is not equally carried every way , but diffuses it self , and has greater vertue upwards than any other way comparatively : 't was imagined , that on the contrary , if it were experimented in vacuo , some variation might happen , from whence some probable conjectures might be drawn of the principles of the natural motion of fire , and that by such an instrument . let the cane ab be about inches , long into which ( being open at a ) put a thermometer of deg . from one end to the other , made flat at that end , where sealed to stand fast at the strait place of the tube cd ; and lest when the quick-silver comes to be poured in at the mouth b , this thermometer should fall upon that placed above , and so by the collision of the balls , one or both be broken ; there may be fastned to the bottom a thread coming out of the mouth b , by which it may be stayed when the cane is turned with the bottom upwards to be filled . the first thermometer being thus placed , let there be put in another exactly correspondent to it ; this inclosing the mouth of the tube a , must be fastned there by its sealed end with the same glass cement at the fire . the instrument being fitted , the mercury must be poured in , and the vacuum made . note , that the strait cd , must be above the height of inches , that the whole thermometer may be exposed to the observers view , and not buried in the quick-silver . when the cane is fix'd , and immovable , apply a great degree of heat to the void space , by the help of two iron balls heated red hot , and held at an equal distance from the cane , but unequal from the balls of the thermometers , inclining more to the lowermost , that so the heat ( which is always carryed upwards by the air ) may be the more equally distributed to the two balls of the thermometers ; we having very often repeated this experiment , yet cannot otherways affirm , but the upper thermometer was indeed most affected by the heat ; we confess the difference is very small , in comparison of what we observed in the open air ; for whereas that was sometimes five degrees in the vacuum , it never exceeded two . neither did some think it would be otherwise , because the air encompassing the two balls , was more heated in its upper part , and so gave a greater heat to its neighbouring thermometer . an experiment of the motion of smoak in vacuo . within the ball of the vessel ab hang a pastile of perfume or other bitumen of a dark colour , upon which the fire has an easie effect . then making the vacuum , cast the rays of the sun thereon with a burning-glass , you may presently perceive the smoak issue from the cake , which instead of mounting upwards , as it uses to do , as soon as parted from the ball , or cake of combustible matter , descends like the spout of a fountain in a parabola : the air being admitted to move it , it immediately rises to the top of the ball. many experiments having been made , that did not require any peculiar apparatus of instruments ( as most of those hitherto related have ) it will be advisable , to avoid tediousness in the discourse , to give a short description of an instrument , and of its capacity , ( the size of our plates being too little to represent it in its full proportion ; ) and then succinctly explain what method we took to menage it most commodiously and easily . that so any who desire to try , and compare the truth of our experiments with their own , may be able to do it ; at least , till they light upon a more safe and easie way . tab p the description of a vessel made use of in many of the following experiments . the vessel then is ab made of glass , whose m 〈…〉 ac is turned outwards flat . the bigness of the neck or mouth is three fingers , the length of the neck ad is four fingers ; the diameter of the ball de is about ½ inches ; the height of the cane ed about inches . close the lower mouth b with a bladder , and set it upon a little leather cushion , swimming upon the mercury in the basin , ( tab . fig. . ) then fill it at the mouth ac ; but because in filling it , the mercury falling directly upon the tube , will intercept and detain a great quantity of air therein ; the small funnel abc ( tab. . fig. . ) was made to prevent it , being of equal length with the vessel : keeping the body of this ab always full of mercury , there can no air get into the shank bc : so the mercury falling gently into the vessel , raises the air before it quietly . when filled , we cover the mouth ac with a glass cover a little convex ( fig. . ) and then with a bladder bound fast about with a waxed thread below in the small of the neck . put then your hands under the ball on each side ; and gently lifting it up , take away the cushion , and immerse the mouth b into the stagnant mercury in the basin : loosen the knot of the ligature at b , and the mercury by its weight falling , will open it , and make a vacuum . when there is occasion to put such things in the ball as may not be covered with mercury , either to avoid mixing therewith , as liquors ; ( which we put in the vessel a , fig. . ) or to prevent their being stifled therein , as animals ; we then use to leave so much air in the neck of the great vessel ad , ( fig. . ) as may serve to receive this little vessel , or the animal we would include therein . this air when the vacuum is made , dilating it self to so large bounds as the capacity of the ball will be so extreamly rarified , as if almost it were not there at all , that in reality , it will be no impediment to any of the effects desired to be observed . but when we would inclose fish therein , we leave no air , nor do we fill the whole ball with mercury , but pour in so much water , as when the vacuum , is made , and the mercury sunk down into the cilinder , the water swimming thereon may fill about half the ball , that the fishes may move , and bear themselves thereon . when we had a mind to put small animals therein , as little lizards , or horse-leeches , or the like , we shut up with them a little ball of solid glass , which following the mercury in making the vacuum stops the mouth of the cane e , and keeps the animals in the ball to be more commodiously observed . all these advertisements may perhaps seem superfluous to some ; but those who are conversant in experiments , and know the difficulties they often meet with in making them , through the impediments and inconveniencies of a material apparatus , will rather approve of , than slight these niceties , it being almost incredible to tell their use , and how great an expence of time may be saved by them . an experiment of sounds in vacuo . hhaving hung a small bell by the thread , instead of the combustible ball in the former experiment , and making the vacuum , we began to shake the ball forcibly , and the bell gave the same tone as if the ball had been full of common air ; or if there was any difference it was too little to be perceived ; indeed , in this experiment the sonorous instrument ( tho the thing is impracticable ) ought to have no communication with the vessel , otherwise we cannot certainly affirm , whether the sound proceeds from the rarified air , and effluvia of the mercury in vacuo , or from the vibration communicated by means of the thread from the percussion of the metal to the glass , and so to the external air encompassing it . nevertheless , we thought of making this experiment with a wind instrument , because it receives its trembling , not from percussion as a bell , but from the impetus of the air rushing out of it . and because it might be too hard a task , if not impossible , to place such an instrument in a vacuum made with mercury , we resolved to enclose it in a vessel exhausted of its air by attraction , so as it has been lately practised by mr. boile , with admirable success , in those his curious and noble experiments ; among which , this was thought of also , though it was not put in practice for want of a fit artificer to make the apparatus . now tho the vessel can never be emptied so perfectly by that way , as by mercury ; yet the air is always so far rarified , as from the manifest difference which appears in those effects that depend really upon the ordinary natural pressure of the air upon them , we may easily come to form a right judgment what they would be in a perfect vacuum . we will here truly relate , what we happened to observe ; confessing , that it is more to shew the manner and method we thought of to make the experiment , than for any certainty we were able to gain thereby : since it may be said , we rather failed , than made the experiment . for this purpose we made a little organ , as abcd of but one pipe , and with the bellows having communication with the pipe by an hollow conveyance in the basis bc. this organ we included in the brass box f , and put the handle hi through the mouth g of this box. this handle we rested upon the pillar , or prop kl , when we had first put it through the ring m , sodered to a small iron rod passing each way through the boards of the bellows , and fastned to them , so that by moving the handle this way , and that way , either the one , or the other was opened and shut , forcing the air into the pipe. then taking a piece of soft leather , and making an hole in it , we put it over the handle , binding it fast upon the mouth g , and likewise gathering it together , we tyed it about the handle ( as in the fig. ) so that all ingress of the air might be prevented ; and through the pliantness of the leather , the handle easily moved every way . all being so prepared , and the cover e cemented on very close ; we began to exhaust the air out of the box with a pump screwed on to a hole in the cover n , and at every draught turning the stop-cock o , that when the sucker was forced down to drive out the attracted air at the valve , and nose p , the air might not re-enter into the box f , and frustrate the labour of the operator . after many draughts , that the air became so rerified , as the leather which closed the mouth g was quite drawn in , and the force of a very strong man was unable to draw back the sucker , or plug ; we began to move this way , and that way , the handle so to convey the subtile air out of the bellows , into the organ-pipe , and listned to the sound . but the truth is , we could not perceive it to differ at all ( not onely ) from that which was made in the same box , when shut up full of air in its natural state , but ( also ) not sensibly from that made in the box , when we had , by the pump forced and condensed a great quantity of air therein : wherefore ( some did say jestingly , either that ) the air has nothing to do in the production of sounds , or is able to do it alike in any state . an experiment , of the operation of the magnet in vacuo . hanging a needle by the thread by which the bell was fastned before , we applyed a magnet to the outside of the ball , and found it was attracted at the same distance as when the vessel was full of air . an experiment of the raising of fluids in small hollow canes in vacuo . amongst other effects of the airs pressure , some have reckon'd that of almost all fluids rising up in small canes therein immersed ; believing , that the small cilinder of air pressing through the little cane upon ( any fluid suppose ) the water , acts more faintly , by reason 't is lessened or straitned by the great adhaesion of the fluid to the inside of so small a vessel : as on the contrary they judge , that the air which freely presses upon the large superficies of the fluid round the out-side of the same cane , being permitted to bear upon it with its whole force ; raises it therein , until the momentum of the water raised , together with that little pressure within the cane , counterpoize that of the external air . to have some light as to the truth of this discourse , we attempted to see what the effect would be in vacuo . we therefore prepared the former ball as was directed for fish , ( tab. . fig. . ) that is , by filling the upper half with water , into this we immersed the small cane ab ( represented in the table of its full bigness ) which was open at each end , and had cemented upon it in the middle an hollow button of glass , counterpoised to keep the cane upright in the water ; then closing the mouth of our large ball ac , we made the vacuum , the water standing to the midst of the ball : and the small cane stood erect , by reason of its hollow button , and the water rose in it up to c ; then the lower mouth being stop'd with a finger , that the air entring might not empty our larger vessel , we unbound it above , and opened the mouth ac , to see if ( the air being admitted to press upon the water ) that greater and more violent impulse would cause any alteration in the level c of the small immersed cane ; but it did not . after this experiment , 't was yet doubted , that the wet received by the whole internal superficies of the little cane , when quite immersed in the water , before the vacuum was made , might serve like glew to detain the small cilinder of water cd whereto it might be kept by adhesion also , as well as it was before by the force of the external pressure : wherefore it was resolved , first to rarifie the air in the vessel which we intended to try the experiment in ; that the first immersion of the cane might be made with the air already dilated , and rarified , and with the inside of the cane dry , that there might be nothing in it to raise more water than that which the weak pressure of that thin air was able to do : and that afterwards reducing the air to its natural state , and then artificially compressing it ; it was thought we might discover some observable variation in the height of the water contained in the cane . tab. . . p. . there was also made another experiment , which was this ; within the ball so often made use of , we placed the syphon abcd , so hung , that when the vacuum was made , it might remain upright in the midst of the ball , and full of mercury ; we then observed , to what degree the mercury rose in the smaller leg ab , and then upon admission of the air could observe no alteration . this experiment was often repeated , always with the same success . lastly , they that took the raising of fluids to a determinate height , to be an undoubted effect of the airs pressure , were desirous to see , if the air ( which presses upon the stagnant level ) when forced to pass through the hole of a very small cane , and must necessarily do so to exert any pressure , comes thereby to be so weakned and lessened , that any observable alteration follows in the height of the fluid so pressed : which they thought would probably happen ; because if one momentum were weakned , the other must certainly preponderate , and so alter the first aequilibrium . to this end , there was taken the cane abcd , whose height ab was inches , and the return bc ½ inches , drawn to a greater degree of smallness than is represented in the figure : this being open at a , and d , was filled with mercury at the mouth a , till it came to d , the mouth of the return which we then sealed at the flame of a candle , and compleated the filling of the cane to a , and tyed it over fast with a bladder ; then we broke off the end d , and the mercury began to run out very slowly , contrary to what we have observed , when the air pursued it at the other end ; whereas , instead of air , the cane had now a vacuity , which increased gradually from a , so that the mercury was no otherwise forced out , but by the weight of that which was above / , reckoning from c towards a : and it immediately stop'd when it came to f the very same height above c , as the mercury was off in another tube immersed in a large vessel at the same time . after this , holding the cane perpendicular to the horizon , by lifting it gently up and down , we caused a motion in the mercury , so that by the vibration of it backward and forward , in the two arms of the vessel , there ran out at each vibration a little mercury at the beak d ; so that when the cane and mercury were at rest , there remained a small part of the little cane , empty of mercury gcd . so the air pressing upon g , tho strained through so narrow a passage as d , yet had not lost so much of its force , as to cause any sensible abatement of the height of the cilinder f c. from all these experiments , and some other of a like nature , which we have now no time to relate , some thought they saw good grounds to affirm , that that opinion of a more languid pressure made by the air through so narrow conveyances , taken absolutely so , is not sufficient to produce this , and the like effects ; but they believed , that there must be at least allowed some other concurrent cause . an experiment of water in vacuo . that noble observation of mr. boiles , of the boiling of warm water in vacuo , made us above measure curious , not onely to see so rare , and surprizing an effect , but also gave us an hint , and desire to try the same experiment with simple water , and also with water brought to as great a degree of cold , as it is capable of ; without freezing . there was put into the vessel ( represented by fig. . tab. . ) a quantity of natural water , unaltered from its ordinary temperament : in this , after the vacuum was made , there appeared a shower of small drops , which tho they were in great plenty , yet came very slow , and the water lost nothing of its transparency : their motion was upwards , till the showr gradually ceasing , the water became sedate , and quiet as at first . the warm water , as soon as ever the vacuum was made began violently to boil up toward the top of the vessel , with a noise not unlike that made by a cauldron boiling very fast ; but upon opening the ball , and taking out the included vessel , we could not observe any heat acquired by this ebullition . the chilled water threw up four , or five small bubbles , and then rested , without any other sensible change , or alteration . note , that upon the admission of the air , the shower of small drops ceased immediately in that water of a natural temperament ; as likewise the boiling of the warm water . an experiment , of snow in vacuo . at first we put in a small piece of snow , of which upon the fall of the mercury there scarce appeared other than the melted water . this so hasty dissolution thereof seemed strange to us ; wherefore to make the experiment more clear , we repeated it with a larger piece made somewhat cilindrical , as long , and big as could be put into the ball : which being filled with mercury , we thrust the cilinder of snow into it . but slipping out of his hand that immersed it , and so swimming upon the mercury , we might perceive that in the very act of immersion , the mercury had preyed upon , and eaten off a good part thereof ; and the dissolved water swam upon the mercury . so we concluded , that it was the mercury which melted the first small piece of snow so suddenly , and not the vacuum , as at the first view it seemed to be ; wherefore putting the snow in again , closing the vessel , and making the vacuum , the little that remained , was as slow in dissolving , as it used to be in the air . this experiment was made in the summer , so that the snow was not in flakes ( solla , we call the snow at florence , when it falls like down , before it is frozen together ; ) but some of that taken out of the conservatory where it was trodden down , and pressed together . an experiment of the dissolution of pearl , and coral in vacuo . this experiment we owe likewise to mr. boile , which was after this manner . pearles , and coral ( as is well known ) are dissolved in vinegar . tho this action proceeds very slowly in the open air , and consists in the curious discharging of very small bubbles , which rise from bodies of the pearl , and coral themselves : yet they do not rise so thick , as to hinder the transparency of the vinegar ; especially , from the coral , which if not finely powdered , is much slower in dissolving : but pearls being softer , afford a greater plenty of bubbles . we desired to see each of them severally in vacuo ; and observed so great a quantity of bubbles to arise from each ; that the vinegar was raised all in froth , and run over the vessel , which therefore shewed as if it had been full of milk , or pure snow : then we gave admission to the air , whereby the froth was immediately sunk , and the vinegar with its natural transparency began to act as before . we will not omit here an effect accidentally observed in this dissolution , which was this : the pearls when they sink to the bottom , gather into one , or more little bubbles of air , which naturally rising up , carry the pearl with them : but as soon as ever the bubbles rise above the vinegar , and by the chock of the air break , their covering is curiously scattered about . then the pearl sink down again , and at the same time other parts thereof gathering into new bubbles , raise themselves . and so all the while the ebullition , or fermentation lasts , there is a continual motion of them up and down through the vinegar . a relation of variovs accidents , observable in some animals included in vacuo . from the very time torricelli found out his first experiment of mercury , he had thoughts of including several animals in the void space , to make remarks upon their motion , flight , breathing , and all other observable accidents : but not being then provided with fit instruments for this purpose , he was contented to perform what he was able to do : for small , and tender animals oppressed by the mercury , under which of necessity they must lye , to be at the top of the vessel when inverted and immersed in the stagnant mercury , would be most commonly dead , or expiring ; so that it would be hard to determine , whether they had received more damage from the suffocation of the mercury , or from the want of air. and either for this cause he forbore , or was deterred from attempting the experiment in an open vessel , misdoubting the sufficiency of the ligature to sustain the air , bearing thereon with its whole weight : and besides , he was diverted soon after this invention by other employments which wholly took him up , that he had no time to apply himself to this , and give it a greater perfection , which it is probable he would have done , if a too hasty death had not prevented him . but we being satisfied , that the force of the air was not so great that the cement , and a bladder well tyed down , was unable to withstand it ; have always successfully made use of a vessel open at both ends , as already hath been shewn , and as we have also done in these . wherefore , we will now proceed to give an account of the accidents observed in divers animals included in this vessel ; as follows . an horse-leech being kept in vacuo above an hour remained alive , and well ; freely moving her self , as if she had been in the air. the same did a snail ; in both these , tho deprived of the air we could observe nothing to argue it had any effect upon them . two grass hoppers were for a quarter of an hour very lively , continually moving up , and down , but not leaping : upon the admission of the air they leaped away . a butterfly , whether hurt by the hand in putting it into the vessel , or whether it suffered from the want of air , 't is certain , that as soon as the vacuum was made , she was quite deprived of motion , except a scarce discernable , and languid tremour in her wings , which upon the ingress of the air shoke very much ; but we could not discover well , whether the animal it self , or the motion of the air caused it ; but upon taking out of the vessel , we found it dead . there are a sort of flyes larger than ordinary , commonly called moscone in italian , that make a great buzzing through the air with their wings : one of these ( which being shut up in the vessel , continued to buz very vigorously ) as soon as ever the vacuum was made , fell down as if it had been dead : and the noise of its wings ceased ; we presently gave it air , whereupon it moved a little , but the remedy was too late ; for it was scarce taken out before it died . a lizard in vacuo quickly grew sick , and soon after closing her eyes , seemed to be dead : but we agreed afterward , that we observed some respiration , perceiving a little swelling in the thorax , between the fore-legs : we continued the confinement for the space of six minutes , in which time it had lost all breathing , and appeared dead : we then admitted the air , which so recovered it , that presently the vessel being opened , she leaped out , and ran away ; catching it again , we included it the second time , and she appeared sick , as before ; but the air revived her again : we imprisoned her the third time , and in ten minutes after some strainings , as if poysoned , she vomited , and fell down quite dead in the glass . another little lizard in less time suffered the same strainings , or convulsions ; and then had a little rest , and as if she had taken breath , and gotten strength thereby , she endeavoured several times to creep up the sides of the vessel ; when the same convulsions returned with strange distortions of the mouth , and swelling of the eyes , as if they would have started out of her head ; she turned upon her back , and after a little gaping for breath , dyed . it was after observed , that she had discharged something by the mouth , and anus ; whence the belly became flaccid and empty . another beginning to suffer the same torments , had immediate relief from the air. a small bird , as soon as the vacuum was made , began to gape , and pant for breath ; and shaking its head , hung down its wings , and tail ; after half a minute , when it seemed almost dead , we gave it air , and so at first it seemed to revive , but in few moments shutting the eyes , it dyed . a gold-finch , and after that another , though presently succoured with the air , yet found it too late . so sudden is the irreparable hurt these tender animals receive from the privation thereof . the almost instantaneous death of these birds , may at first view seem to contradict an experiment of mr. boyles , wherein he mentions a larks living in the evacuated receiver , though one of its wings was hurt , about ten minutes . and a sparrow taken with bird-lime endured for seven minutes ; at the end of which , seeming dead , she was recovered with the fresh air : and being again included , and the vessel evacuated , in the space of five minutes dyed . but whoever reflects upon the different ways of making the vacuum in the one , and the other instrument , will confess that the two experiments , how different soever they seem ; do indeed wonderfully agree : for whereas in that , the air is thinned by repeated attractions , and slow , and little more then insensible acquists at each draught : in our instrument , 't is reduced to the greatest degree of rarity by the instantaneous fall of the mercury ; to which , when the air is brought , 't is no longer serviceable to their respiration . and if ( when we had included the animals ) we inclined the upper mouth of our vessel below the perpendicular height of / inches reckon'd from the level of the stagnant mercury in the basin , and opening the lower mouth , we gradually raised it by little , and little to an upright ; we have observed the very same effects , related by mr. boyle ; the air then of necessity passing through all the intermediate degrees of rarefaction , from a greater to a greater ( as it does in evacuating his receiver ) is not so soon rendered useless to the respiration of these animals . a soft crab at first putting in , moved ; then grew feeble , and began to faint away ; when he had stood a little while motionless , or rather with all his members contracted , we gave him air , whereat he seemed revived , and began to move slowly ; but taken out of the vessel , soon dyed . a frog was presently giddy , and notably swell'd all over ; but when the fresh air came in , with a sudden leap , he shewed himself recovered . we inclosed at another time , in the same vessel , an hard crab , and a frog together , the crab seemed to move , till the end of the experiment , which was a full half hour without any , alteration , except perhaps a little swelling . the frog in ten minutes was unmeasurably puft up in every part , and two great bladders appeared on the sides of his jaws , and vomiting up a great quantity of froth at his mouth ( which stood wide open , filled with his tongue , and all the membranes disformedly swelled , and blown up ) in this posture he remained motionless : at the entrance of the air the swellings fell at once , and he appeared quite changed , being extream lank , and thin ; so that we thought him much less than when he was first put into the vessel ; when we took him out , he was dead . the crab as we said before , was alive , but in few minutes dyed . another frog , much swell'd as the former , cast up a great deal of froth , and other things at the mouth : and in half an hour was found quite dead . at the entrance of the air he appeared shrunk up , and lank as the other . the thorax was opened by an acurate anaetomist , who at first could not find the lungs , they were so shrunk up together for want of the air : but by blowing with a straw in at the ductus by which they breathe under their tongue , ( they were redistended ; whence it was visible , the most part of the air which was contained in the animal when first included , was got out to enjoy a larger field in the evacuated space , without tearing , or hurting any of the vessels ; for upon blowing they were all tight , and swelled up . several small fishes which were very lively , were included with a sufficient quantity of water ; and as soon as the vacuum was made , they were remarkably swell'd , and fainting turned up their bellies . they endeavoured several times to keep their backs upwards ; but they still turned again : when the vessel was opened , they sunk to the bottom , where unable to recover , they dyed . we presently dissected one of them , and compared it with another taken alive , which had not been in a vacuum ; and examining the intrailes , we found the little air bladder empty in this ; whereas in the other , it was round and full , as is usual in all fish . in a pretty large barbel the eyes were much swell'd ; the fish turned on his back , stretching out the finns , as if they had been stiff and frozen , with the gills opened wide , and the whole body distended with wind , and so it lay at the top of the water . it attempted by several jerks to turn to its natural posture , but in vain ▪ after six minutes , upon the return of the air , the swelling of the eyes asswaged ; and tho the thorax returned to its due proportion , yet it was forced to keep at the bottom continually gaping , and unable to raise it self in the water ; and being put into fresh , it soon dyed : being opened , we found the bladder all shrunken , when that of another fish ( dissected alive , tho five times less than this ) was yet much larger , and turgid . an eele stayed a long time without fainting , or any diminution of its vivacity : but at last in an hour that dyed also ; and being opened , the bladder was empty , as they of the other fish were . another barbel having been in vacuo , and refresh'd again with the air ; by great chance was taken out alive : wherefore we gave him his liberty in a cistern where others were kept , being above inches deep . this fish , whether it was easier for him , or whether he was necessitated so to do by the emptiness of his bladder ; 't is certain , for the whole time he lived , which was about a month , ( altho we chased him about , and frightned him , by stiring the water ) he was never seen to raise himself , as the other fishes did ; but still left a mark behind him on the bottom , sweeping it with his belly : his bladder , when dead , to sight was swell'd with wind as it is naturally , but was very much softer to the touch , than those of other fish are . observations upon the bladders of fish in vacuo . the bladder of a great fish swell'd with wind , as it was taken out , being put in vacuo , shewed no alteration there : wherefore we opened the vessel , believing that nothing else could vary the experiment , except the coats of the bladder were of too strong a texture to be burst by the force of the air naturally included therein : but upon the first ingress of the air , the bladder appeared neither more nor less full than we had observed it in fish killed in vacuo ; a clear sign , that the greater part of the air in the bladder , by forcing , or taring the swim , gets out through some invisible passages ; and any little portion that remains , by the increase which it receives in vacuo , serves to keep the bladder distended as at first . then being desirous to find , where the air gets out of these bladders , if by any ductus naturally there , or made by the force of the air ; we took , with the greatest care possible , the bladder out of another fish , and tyed the two ends with a silk , supposing , if there were any passage , it must be at one of them : this in vacuo appeared full , as the other had done ; but upon the ingress of the air , it shrunk up after the same manner : wherefore , to find the passage where the included air breaks away , we made a small hole , to put in a little glass cane , and bound the bladder fast about it , ( the extremities being yet tyed ) and blew wind into it through the cane ; which being in great plenty , swell'd the bladder ; but at the same time , we perceiv'd it got out of a small crack at a , ( which must be that , where the air in vacuo found a vent ) to which , holding a lighted candle , we might perceive the flame to wave ; and viewing it attentively , when distended , it was not so small , but it might be discerned with the naked eye . having thus found , that the air did not get out at the ligatures made , whilst to free it self , it was forced to make a new crack , we had a mind to see if it gets out after the same manner in the bodies of fishes kill'd in vacuo ; that is , by breaking the thin membrane of the bladder , or by finding some hidden passage : wherefore taking carefully the bladder out of a roach that dyed in vacuo , we made a hole in the smaller end , and put a cane in , as before , and blew very strongly , but it held tight : an evident proof , that the air without breaking it , has some vent , which the weakness of our eyes could not discover . we then thought of making the experiment under water , which perhaps might detect something to us : so we took the bladder out of the fish alive , and well tying it in a net , fastened a convenient weight , and sunk it in water , and then made the vacuum , when we might see many small bubbles of air issue from the slender part thereof ; where 't is probable , the natural meatus is , which transmits it ; when the vessel was opened , the air shrunk it like the other . lastly , willing to see what way the air takes from the bladder to get out of the fishes body , whether by the gills , or mouth ; we covered a roach with the same net , that by affixing a weight it might be kept under water ; the vacuum being made , we saw a great deal of air come out of his mouth in large bubbles , as before from the submersed bladder . here should have been the end of these experiments ; but while these sheets were in the press ; one of our academy having thought of a way to facilitate very much the management of our vessel to make the vacuum , we will not omit to set it down here ; and the rather , because we found it indeed very convenient . the invention consists in joyning to the cane be ( tab. . fig. . ) the retum bfg ( designed in the figure by the prick'd line ) for putting as usual the mercury in at the mouth ac , when it comes up to g ; in the return , we tye it down close , and fill it up to ac , where being closed after the usual manner , it is sufficient to open the mouth g , and without any immersion , all the mercury above / inches taken from g towards e , runs out : and note , that the ball fg serves to keep in the mercury in the fluctuating motions it makes in the two branches of the cane , ( before it rests ) caused by the impetus of its fall . this is all at present touching the natural pressure of the air , and its various effects . experiments of artificial freezing . among the rest of the stupendious works of nature , that admirable power has been always much regarded , whereby she binds the slippery waves , changing their fleeting inconstancy into solidity and hardness . this effect , tho daily before our eyes , in comparison of others more secret and rare ; yet has continually afforded ample subjects of curious speculation to the mind of man : for , whereas fire , when disingaged in swiftly winged sparks , by insinuating it self through the close pores of flinty and metalline bodies ; opens , melts , and reduces them to a perfect fluid : so cold on the contrary ( a much stranger thing ) stops and consolidates the most fluid liquors , changing them into downy snow , and glassie ice ; which upon the least ray , or warm breath , break prison , and steal away in their first fluidity again . and ( which is yet more amazing ) so violent a force of cold in freezing , is observed penetrating not onely glass , but even the secret pores of metals . as in the subterranean caverns , and deep mines , the raging flames impetuously divide , and in fury open all those dark passages ; so cold in the act of freezing , cracks shut vessels of thick and strong glass ; stretches , distends , and at last , tears those of pure gold , and bursts asunder those of cast brass ; and of such thickness , as to break them by dead weight would require perchance , nay assuredly , some thousand weight : upon this strange phenomenon of freezing , observable in water more than any other fluid : some have thought , that where the cold operates in its proper laboratory with fit materials , it reduces the pure water to such a temperament , that it turns it into even the hardest rock-cristal , and gems of various colours , according to the different tinctures received from the neighbouring mineral steams ; nay , even into the invincible hardness of the diamond . and plato was of this opinion , that diamonds were generated of the remains of those waters whence in the secret caverns of the earth he thought gold was produced ; and therefore a diamond is called , the off-spring of gold , by that divine philosopher in timaeo . but to return to the causes of freezing . the ingenious in all times have had various sentiments thereof : whether it does indeed come from any real and proper body of cold ( which in the schools they call positive ) that ( as light , and heat are originally in the sun ) is either in the air , or water , or ice it self ; or any other part of the vniverse as its proper place , and residence , where it has its repository and treasury ; in which sence the words of the divine oracle in sacred writ may be taken . hast thou entered into the treasures of the snow , or hast thou seen the treasures of the hail ? or whether cold is nothing else but a total privation , or driving away of heat . touching this , and other curious observations of the artifice used by nature in freezing ( whether she atchieves her end by contracting , or rarefying the fluid ; whether the change proceeds slowly , or instantaneously , &c. ) we were induced to try several experiments of artificial freezing , made by the outward application of ice , and salt ; fully perswaded , that the operation does not at all vary from the procedure of nature , when by the pure and simple cold of the air she congeals water . what hitherto we have had the good luck to observe , upon so vast and boundless a subject , capable of so great and endless observations , will be offered to you in the following experiments . experiments to know , if water dilates it self in freezing . it was the thoughts of galileo , that ice was rather water rarefied , than condensed ; because , ( says he ) condensation consists in diminution of bulk , but increase of weight ; and rarefaction in the increase of lightness and bulk too ; but water in freezing gains in bulk , and ice is lighter than water , since it swims thereon , &c. this being supposed , ( which experience will sufficiently prove ) we were curious to see what water would do when confined in a vessel where it had not the least room to dilate , yet on all sides being encompassed with ice to freeze it ; since we still observed ( agreeable to galileo ) that water as well frozen into great mountains of ice , as in the smallest pieces , and of what figure soever , continually swims upon the surface of other water ; a certain proof , that in the act of freezing , ( the increasing of the bulk considered , ) it grows lighter ; whether it be by the interposition of small and insensible vacuities , or interspersion of minute particles of air , or the like matter , after the manner of little blebs in cristal , and glass , ( for such they appear to the eye through the body of the ice when held up against the light ) in some places thicker , in others fewer ; and if the ice be broke into small pieces under water , they rise up through the water in great numbers . the first experiment . taking a vessel of thin silver plate , with two covers to screw on , such as we use to cool our sherbet , and other drinks in summer ; we fill'd it with fair water cooled with ice , and then set it to freeze : it was cooled first , lest if it had been put into the vessel at all rarefied by heat , upon the first refrigerating it should contract , and by that means gain room to dilate in afterwards in freezing . when 't was thought the ice outwardly applyed , had done its work , we took the vessel out , and opening the first cover ( which was concave ) we found the second cover crack'd , and covered over with a thin cake of ice , caused by the water forced thither , by the rarefying of that within the vessel as it froze . neither can it be thought , that this crack was caused rather by condensation of the water in freezing ; which being constrained by the violent force of the cold , to withdraw it self into a less space , for the avoiding a vacuum , gradually drew down the cover as it retired , 'till at last , unable to stretch any farther , it crack'd . i say , this is improbable ; for if so , we should have found the cover bent inwards , whereas it was forced outwards , and considerably raised from the flatness it had before , as was also the superficies of the ice in the vessel ; moreover , the edges of the crack turned outwards : whence we gather , how great the impetus must necessarily be , that caused it ; and would have been much more considerable , if a larger proportion of water had been congealed ; whereas , breaking the first cake , we found almost all the water fluid . tab. . p. . the second experiment . finding that the force of freezing far surpassed the resistance of this our first instrument ; we thought of making a ball of cast silver of the thickness of a crown piece , and of an oval figure , to open in the middle with a screw , and with a top screwed on at the end of the neck , as in the figure : then shutting this vessel , and screwing fast the middle screw with a vice , we filled it with water at the neck , and screwed on the little cover , and set it in a mixture of salt and ice to freeze , and in a little while taking it out , we found it perfectly sound , and whole ; opening it in the middle , we took out a shell of ice , but it was very tender , and less transparent than usual ; and perchance more dense and close ; for being put in water , it did not seem to buoy up so well , but rather ( as all thought ) dived towards the bottom : in the midst was a cavity as big as a large almond without the shell . this experiment was repeated after by us , with the same success . the third experiment . there were some that wondered at this unexpected accident , seeming at first view to contradict , not onely the opinion of galileo , but what is more , to be inconsistent with it self ; seeing tho this ice appeared condensed , and heavy , in respect of that made by the cold of the air without any art ; yet it must necessarily be lighter than water , because it in some measure still swam thereon : and so much the less could they satisfie themselves , as they saw the vacuity always in the middle of the water congealed : whence it seemed necessary to conclude , that the water , which fluid , sufficed to fill the ball ; being frozen , withdrew it self into so much a less space as the aforementioned vacuity ; from so manifest an inconvenience , they were inclinable to think , there must be some fallacy , and therefore set themselves to observe very nicely the whole progress of the experiment ; so taking the vessel very often out of the freezing mixture , and carefully viewing it on all sides , they perceived an almost insensible boiling , and bubling out at the middle screw , from time to time ; a manifest sign , that the water ( so great is the force of its rarefaction ) crept through the spiral passages of the screw ; upon this , the screw being waxed , and the ball again filled , it was set in the ice and salt to freeze ; and tho 't was many times taken out , there was never observed any bubbling , or any hissing heard as before ; but after the freezing was done , upon taking it out of the mixture , the vessel was open on one side of the middle screw , the rarefying power of freezing being great enough to force the screw ; the experiment being often repeated , had still the same effect ; and being again tryed in a ball of brass with a screw of twice as many threads as the silver one had , it still shewed the same trick . the fourth experiment . to avoid this inconvenience of the screws , we got some balls made of glass half a finger thick , and filling them with water , set them to freeze , being first sealed at the flame of a candle : the effect was exactly the same as that of the first vessel made of plate ; for they all were diversly broken , and split : some had their necks quite thrown off ; others through the unequal thickness of the glass , or irregularity of their figure , were burst on one side ; others were tab. . p. . crack'd all over . and 't was observable , that the neck was generally broken off ; when the whole ball was covered in the mixture of ice , and salt , so that the water in the neck being of the least bulk , 't was first frozen solid there , and by that means stop'd , and forced the ball : for in the procedure of the freezing , the remaining water endeavouring every way , and either finding the neck the weakest part , or the ice therein being as a cone , or wedge to split it , it still most easily brake through there ; which never happened when the upper part of the ball was left uncovered with the freezing mixture . how great the force of this rarefaction was , may be gathered from this ; that when the necks were not turned downwards , upon the vessels bursting they flew off into the air , five , or six feet high , throwing up a great deal of the ice , with which the balls were covered . the fifth experiment . at last we resolved to cast a ball of brass all of one piece about two crowns thick , having but one mouth at the foot thereof , so made as to be very close shut with an exquisite screw . then to take the lump of ice out whole , we made a small crease round it , where by putting it again in the lare , it might be cut in two in the midst , which shewed a strange accident in the water ; for this small inequality , as little as it was , made the ball burst in that place . whereupon we made another ball , and without weakning it in any part , set it to freeze ; but this was broken , as all the other ( for we tryed it often ) in that place which the water found most defective . the sixth experiment . the last experiment was made with a ball of fine gold of the size represented in the figure : this having undergone many freezings without any visible crack , caused at first no little wonder : and some began to doubt , whether , or no , the space requisite for the freezing by the diminution of the thickness of the metal , by the force of the water , and by reason of its softness , might insensibly be comprest , ( as tin , silver , and gold it self , become more compact by being hammered : ) but at last observing , that whereas the ball before freezing , was flatted so , that it would stand upon the bottom ; when it was taken out of the freezing mixture , it would not stand upright ; every one was well satisfyed whence this happened : and because it seemed to us perfectly spherical , to be the better assured thereof , whether it would remain of its first size ( if it did not burst in repeating the experiment ) or whether it would stretch bigger ; we made a ring of brass exactly fitted to the vessels greatest circle . all along in the freezing , by examining it with this ring , we still found it grow bigger , and bigger ; that pure metal , by reason of its softness and pliantness , still dilating and stretching it self : and perhaps , if it had been made of cast metal , the effect would have been more conspicuous ; but being made of two pieces , it at last burst at the place where it was sodered with silver , and the crack beginning at the soder , ranslanting down into the gold also . an experiment , to measure how great the force of rarefaction may be in water shut up in close vessels , to freeze . to obtain this , we thought of making a metal ball of brass , like the former , but perfectly round , and according to our estimation , so much thicker , that the force of rarefaction should be unable to break it ; and filling it with water , to set it to freeze , as before ; the cover being fast screwed down . this was done , and at first we found that the water was frozen without any running out , or cracking the vessel : wherefore we put in the lare , and ( keeping it as near as possible of the same figure ) there was taken off every where a thin coat of metal ; and then 't was set to freeze the second time with water ; and not being burst also , altho it was frozen ; we again turned off a thin skin from the ball ; this experiment we repeated with three balls , the thickest whereof is represented by the . fig. which seemed to us the greatest thickness the force of rarefaction in freezing water could over-power : having proceeded so far , we were desirous to reduce this to the force of dead weight , and the most probable means we thought of , was to cast a ring of the same metals and hardness , and exactly of the thicknes of the ball , turning the inside conical , and fitting thereto an iron cone , so that the iron might rise about the breadth of the ring , above the upper edg thereof ; being thus prepared , we thought of putting the ring over an hole made in the midst of a thick stone table , something larger than the bore of the ring ; we then thought to proceed to lay on weights upon the top of the iron cone ; or at least , force it down with weights hung to an hook made at the lower end thereof , that so the force being perpendicular , it might equally drive the iron into the ring , and then leasurely adding small leaden weights , we might know the least weight capable of bursting the ring : and to be secured , that the bearing of the ring upon the roughness of the table might be no hindrance to its breaking , we thought to fasten round the hole of the table , a plate of polisht steel , and smooth the under-side of the ring , that it might upon the least touch slip upon the steel : but because an immense weight was but sufficient to conquer so great a resistance , we thought to obtain our end , by making the experiment with several much smaller rings , but of different sizes , and with more managable weights ; and so by examining the resistance of these rings , and comparing the repeated trials , to come near the knowledge of what would break the first ring , of the same thickness of the ball ; and by consequence , the force of rarefaction in freezing . these were our thoughts ; but still finding upon cutting our balls that were crack'd in the freezing , several inequalities , and defects in the founding , proceeding either from the wind , or dregs of the metal ; when infusion , we were discouraged from prosecuting the experiment , upon so many uncertainties ; nevertheless , we forbear not to relate our intentions freely , tho we came short of our end ; yet it may serve for an advertisement to others , not to take a wrong path ; and perchance , excite the ingenious to find out a means to obviate these difficulties , or a happier journey another way . experiments , to measure the utmost expansion of water in freezing . the first experiment . we made this experiment two ways , by measure , and by weight ; that by measure , was after this manner : we procured a glass cane , drawn as equal as possible ; we sealed it at one end ; and filling it to a certain mark with water , we set it in ice very well powdered , and incorporated with salt to freeze : then comparing the height of the cilinder frozen , with that of the cilinder fluid , having the same bases , the proportion was found to be as nine to eight . the second experiment . we did not think fit to rest satisfied with this one experiment , judging it little less than impossible , to find a glass cane , ( which has no other rule to draw it by , than the equal breath of the artificer ) so truly cilindrical as to take away all scruple of the proportion of the cilinders of water contained therein : wherefore to have a more regular vessel , we took the barrel of a pistol , and turned it within to the truest cilindrical figure attainable by a material instrument , shutting the touch-hole with a steel screw , and covering that with a polish'd steel plate , we poured in six fingers water , and thrust in a turned cilinder of box , of the exact size of the remaining part of the tube , well oyl'd and greased , that it might not imbibe any water : when it was driven in so far , that the mouth of the barrel was well stop'd , we inverted the cane , that the water might all rest upon the base of the cilinder , and unscrewing the touch-hole , we forced the cilinder ; of box in further , till the water began to run out ; then screwing in the pin again , we set the barrel upright , and marked how much of the wood stood out , and covered it with the freezing mixture sprinkled with aqua vitae , which , as is well known enforces the freezing very much . when it had lain there about minutes , the mark made at the nose of the barrel upon the box , was raised the thickness of a crown , and presently after two more , where it stayed , tho we reinforced the cold by a great quantity of fresh snow and salt : after a full hour , we took the barrel out , and found it so cold , that we could scarce endure it in our hands ; whence we gathered , it was throughly frozen : and that the rather , because unscrewing the touch-hole , and striking the end of the box cilinder against the wall , we were not able to force it an hairs breadth in ; and except a few drops at the touch-hole , we could not observe any water between the cilinder and barrel ; and by trying with a piercer , we found it solid ice : for all this , we were not certain the water was all frozen ; nor could we be easily satisfied , because of the opacous tube . and 't was possible some water might get out at the screw of the touch-hole ; and so part of the tube between the cilinder of ice and box , remain empty . or in fine , the water when at perfect liberty , may rarefie in a greater proportion , than it can do when under the constraint of a close vessel , as it was here ; for the box was so fitted to the barrel , and by imbibing the water , notwithstanding the oyl so swell'd , that after the ice was thawed , and the water poured out at the touch-hole , we were not able to pull it out with a pair of pincers , or a vice ; so that we were forced to burn it out . the third experiment . being sensible of the many difficulties we encountered in endeavouring to gain these proportions by the height of the cilinders upon the same basis , and a metalline tube , we betook our selves to the other experiment of weight : this we tryed with a transparent glass cane , and weighed the water put therein to freeze , and afterwards , as much ice as filled that same space in the cane , in a pair of scales that turned with the / part of a grane ; and the proportion was found to be , as , to / , little less than that observed in the first experiment of measure , which was as to , the same as to ⅛ ; finding so great an agreement in the proportions not to flatter our selves with this success , we repeated the first experiment with the same cane , and found it as at first , as , to : and we were satisfied , that the weight was not altered for keeping the glass cane close shut the whole time of the freezing , and till it thawed again ; our balance shewed it to be of the very same weight as at first . experiments , touching the procedure of artificial freezings , with their wonderful accidents . the first vessel we made use of in these experiments , was a bolt-head of glass , about / inches diameter , with a neck about inches long , slender , and divided into minute degrees ; into this we poured fair water to a sixth part of the neck , then setting the bolt-head , or ball in the freezing mixture , as we used to do to freeze liquors ; we attentively observed the motion thereof , by viewing its superficies : we knew before , ( as indeed , few are ignorant of ) that from the first application of cold , it contracts all liquors , lessening their bulk ; and this we found true , not onely in the aqua vitae of the thermometers ; but also , we had often made the experiment with fair water , oyl , mercury , and many other fluids ; on the other side we had taken notice , that the water passing from a simple coldness , to lose its fluidity , and receive consistency , and firmness by glaciation , does not onely return to its first bulk , but so far exceed it , as to burst vessels of glass , and metal with great violence . but we were yet ignorant , what period these several alterations ( produced by cold ) observed ; neither was it possible for us to attain it in opake vessels , as those of silver , brass , and gold were , hitherto made use of in the freezings : wherefore not to fail in this , which seemed to be the very life of all these experiments ; we had recourse to vessels of cristal , and glass , hoping by the transparency of the materials , to be satisfied in the procedure of the experiment ; since upon every motion of the level in the neck , we might take the vessel out of the mixture , and mark the correspondent alteration therein . but the truth is , we found greater trouble than at first we imagined ; to gain any certainty as to the periods of these accidents . but to relate the success more distinctly , you must know , that upon the first immersion of the ball , as soon as ever it touch'd the freezing mixture , we observed in the water in the neck a little rising , but very quick , which soon subsiding , it fell in the neck , with a motion regular enough and a moderate velocity retiring to the ball , till arriving at a certain degree , it stop'd for some time , as far as our eyes could judge , immovable . then by little and little it emounted , but with a very slow motion , and apparently equal , and then of a sudden without any proportionate acceleration it flew up with a furious spring : at which time it was impossible to follow it any longer with the eye , instantaneously running through the decades of degrees . and as this fury began of a sudden , so of a sudden it ceased , changing from that great swiftness to a movement , though very fast , yet incomparably less swift than the precedent : and with this it continued to rise most commonly , till it ran over the top of the neck ; and all the while these things happened , were observed several little corpuscles of air , or some other more subtil body to arise , and pass through the water , sometimes in a greater , sometimes in a less proportion : this separation was not visible , till the water began to receive an intense degree of cold , as if the force of the cold had the faculty of secreting such a matter from the water . after this , we were willing to see , if these alterations kept any kind of equality or proportion with each other ; wherefore we repeated the freezings , scarce one ice being dissolved , but we set it again to freeze : but the water always froze with the same series of changes : yet because they did not still every time rise to the same marks or degrees in the neck , we began to imagine , there was no fixt period ; for which , it seemed we had some reason . at last it happened , that in often repeating these experiments , we by chance let the water in the bolt-head freeze in the neck first : ( of which we spake in the fourth experiment of freezing , ) and so brake our vessel . whereupon , we were forced to make another ; this we blew less than the former , that the cold might soon insinuate it self through all the water ; we also made the neck longer , to the height of ● / inches , that it should not run over . this we filled to deg . and set it to freeze in ice very diligently ; heeding it we found at first , that all the accidents of subsiding , rising , resting , remounting , swiftly running up , and stopping again , were the very same ; ( i. e. ) happened always when the level of the water was at the same mark or degree in the neck ; for upon putting it in the ice , we observed , it was reduced to the same degree , as in the former tryal : that is to say , at the same temperament of heat and cold ; taking the whole instrument for a nice thermometer , by reason of the largeness of the ball , and proportion of the neck ; being satisfied so far , we proceeded to find the exact time of freezing ; and to obtain this , we took the ball out of the mixture often , yet as often as we tryed it , we were never so successful as to find the first small veins , or stiriae of ice , but it was either all fluid , or all over frozen ; whence it was easie to gather , that the act of glaciation must be very quick : and whoever should happen to take it out of the mixture in the very instant that the water begins its swift car●ere ; might certainly observe some notable alteration therein : and because we had so often taken out , and immersed the ball into the mixture , we were not well assured of the point of its change ; we let it stand therefore , and be reduced to its first mark , and placed it again in the mixture , and took notice of the degrees whereat it began to mount so swiftly ; and half a degree before it came to it , we took it out , and very needfully regarding it with the eye , the water in the ball , through the transparency of the vessel was easily discerned to be yet all fluid ; but the before received impression of cold still acting ( though it ▪ was now taken out of the ice ) when it was just arrived at the point , with a swiftness indiscernable by the eye , and therefore scarce to be conceived , forced the water through the neck , and in an instant took away all transparency from the ball , and changed its fluidity into ice . there was no reason to doubt of its being wholly converted into ice ; and that it was not onely outwardly crusted over , because in thawing it loosened first from the sides of the glass , lessening by degrees , till at last it was like a small lens of ice which was in the end dissolved . we were well satisfied by often repeating the experiment , that it was just as we have related it ; and that we were not imposed upon . tab. . p. . we were after this , very desirous to see the order and method observed by divers liquors in freezings which for brevity are set down in the following tables ; wherein state natural , signifies , the degree whereat the water , or other fluid stood ( before glaciation ) in the neck of the vessel . rise upon immersion , is the first leap made by the water upon the balls first touching the freezing mixture . this , ( as the following experiments will more clearly shew ) proceeded not from any intrinsic alteration of the fluid ; but from the extrinsic cause of the vessel : whence it is , that varying sometimes a little , it communicated some variety to the other changes through which the liquor passed in freezing ; but whereas this is it self but small , its variety is also but little , and what it communicates to the subsequent changes very inconsiderable . abatement , or fall , denotes the degree to which the water is reduced ( after the rice upon immersion ) when it just begins to receive the impression of cold. rest. is the degree whereat the water stands for some time after its fall , without any apparent motion . remounting , shews likewise the degree to which the water is raised from its lowest fall , by means of rarifaction , with a very slow , and seemingly equal motion , altogether like the first , wherewith it subsided . spring upon glaciation , signifies the degree to which the water rises with that extream velocity upon the very point of glaciation . we said before , that after this spring or start , the water does not stop upon a sudden , but continues to rise with a motion swift enough , though incomparably less than the preceding : but of this subsequent motion , we have taken no account , it proceeding onely from the prosecution of rarifaction in the ice already made , or to say better , from the ice shooting in the ball by little and little , as it hardens after the fury of the first impetus . this we call the first shooting of ice , which is ( as we have found upon breaking the balls ) from a very tender and weak beginning ; and like sherbet , when it is a little too hard , being of no closer a consistence than the first coagulations of liquors . moreover , it happens that this way of freezing , shews not the utmost rarefaction of fluids violently frozen , it being impossible without bursting our instrument to reduce the ice to a perfect solidity . we have likewise , to shew our utmost diligence , and exactness , made use of a thermometer and pendulum in each experiment of freezing : that with the thermometer we might see at what degree of cold , and with the pendulum at what time every change happened to the liquors : wherefore in the same box with the ball , or bolt-head , we put a thermometer of deg . but indeed , we found great inconveniencies , both in noting the degrees of cold shewn by the thermometer , and the spaces of time given by the vibrations of the pendulum ; so that we must confess , all our diligence was fruitless through the difficulty and impracticableness of applying an equal proportion of cold to the ball , and to the thermometer ; by reason of the inequality of the pieces of ice , and quantity of salt sprinkled . and the cause is , that in artificial freezing we make use of snow or ice , which though ever so well bruised , and as it were ground to powder ; yet upon mixing it with the salt , they become one solid mass , and as hard as stone ; so that it is impossible to close it round about the vessel , or be assured , that it touches every where alike : yet rather than be deficient , we have set both down in our tables , that is , the degrees of the thermometer , and the vibrations of the pendulum ; leaving it to the discretion of the reader , to make a due estimation of such remarques . the first freezing of spring water .   the deg. of the vessel . differ . deg. of therm . differ . vibrat . diff. state natural         rice upon immer . ½ ½ abatement . ½ rest .   remounting . spring upon glaciat .       note , that of the vibrations of the pendulum set down in this , and the four following tables made one minute . the second freezing of the same spring water .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural .   ½       rice upon immers . ½ ½ ½ abatement . ½ rest ½   remounting . ½ spring upon glaciat .       the third freezing . of the same . deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural   ½       rice upon immersion ½ abatement ½ ½ rest ½   remounting ½ spring upon glaciat . ½       from these three examples of freezing , the same water may be observed , that the state natural of the water was not all three times exactly at the same degree caused by the different temperament it had at one time , from what it had at another , from the external accidents of heat and cold ; whence likewise all the other alterations happening to the water , did not precisely keep their degrees ; nevertheless by reducing in the second and third experiments the state natural to deg . and also substracting in the like proportion from all the other heights , you will find that they differ from the degrees noted in the first table very inconsiderably . the first freezing of mirtle flower water drawn off in a cold still .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural ½   ½       rise upon immers . ½ ½ abatement ½ ½ rest   ½ remounting ½ ½ spring upon glaciat . ½       the second freezing of the same water .   deg. of vessel . diff. deg. of therm . diff. vibrat diff. state natural         rise upon immers . ½ ½ abatement ½ rest   ½ ½ remounting ½ ½ ½ ½ spring upon glaciat . ½       in the following experiments of freezing , we changed our pendulum taking one , of whose vibrations made an exact minute . the first freezing of simple rose-water still'd in a cold still .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural ½         rise upon immers . ½ abatement rest   remounting ½ spring upon glaciat .       the second freezing of the same water .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural ½         rise upon immers . ½ abatement ½ rest ½   ½ ½ remounting ½ ½ spring upon glaciat . ½       the first freezing of orange-flower water drawn off in a cold still .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural         rise upon immers . ●● abatement ½ ½ rest   ½ remounting ½ spring upon glaciat . ½       in all the tables of the second freezings of the above-named liquors many be observed how much longer time was requisite to freeze it the second time , than the first ; which we taking notice of , were willing to discover , whether it arose from any intrinsick cause in the liquors after their suffering the first freezing ; or from an external cause in the ice's being less cold after it had suffered the first incorporating with the salt : and for this intent , we emptied the case , and putting in fresh ice and salt , we made trial of the second freezing of the same water .   deg. of vessel . diff. deg. of therm . diff. vibrat diff. state natural ½         rise upon immers . ½ abatement ½ ½ rest ½   remounting ½ ½ ½ spring upon glaciat . ● ½       so that the disserence in time between the first and second freezings must not be attributed to the liquors , but to the ice , which being much dissolved , and weakned , its freezing power arising from the salt requires a longer time to perform its operation ; and indeed , the whole difference between the two freezings of the orange flower water amounted but to a minute and seconds ; whereas , when the mixture was not changed , it arose to minutes seconds ; nay , to minutes seconds ; as appears by the comparing of the first and second freezings of the rose-water , and the first and third freezings of the spring water ; and that the small difference of minute seconds observed in the second freezing of orange-flower water , was meerly accidental , and not from any resistance acquired by the water in being once before frozen ; is evident from the seeond table of the freezing of strawberry-water , following , where the ice being changed , the second freezing happened in minutes seconds less time than the first . the first freezing straw-berry water still'd in balneo .   deg of vessel . diff. deg. of therm . diff. vibrat . diff. state natural         rise upon immers . abatement rest   remounting ½ ½ spring upon glaciat . / ●       the second freezing of the same water .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural   ½       rise upon immers . ½ abatement / rest   remounting spring upon glaciat .       note , that the spring upon glaciation is more or less high , as likewise more or less swift in different fluids : and it seems to be higher and swifter in those that freeze stronger . the freezing of still'd cinamon water .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural ½         rise upon immers . ½ ½ ½ abatement ½ ½ ½ rest ½   rem●unting ½ the water rising with a very slow motion from the state of rest to deg . ½ instead of springing up as it then uses to do , it onely mounted with a quicker pace ; which perceiving , we immediatly took the vessel out of the mixture , and found the water shot into a very tender ice , which melted as soon as ever it was sensible of the air. and note , that of these artificial freezings , some were more weak and tender , as the ice of cinnamon water , and that of rose-water ; others more firm and hard , as that of orange , and mirtle-flower-waters ; than which we found no liquors so hardned at the first instantaneous freezing . we have omitted the repetition of this , and the following freezings , since their agreement may be sufficiently seen in the examples given of each liquor . the freezing of snow water .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural . ½         rise upon immers . ½ abatement . rest .   remounting . ½ ½     and then with a somewhat quicker motion ( tho very slow in comparison of that which the other liquors sprung up with upon the point of glaciation ) it began to congeal at the sides of the glass , and successively from the more outward parts approach'd the center of the vessel with the same equal slowness of rarefaction , and raising of the level in the neck . the ice was not throughout equal as the other , but broken , and shot into irregular veins and rays , and every where interwoven : being repeated , the second freezing was in all respects the same as the first ; and making it with the same water boil'd , we found no great difference . the freezing of fig-water .   deg. of vessel . diff. vibrat . diff. state natural       rise upon immers . abatement rest   remounting spring upon glaciat .     the freezing of the best red florence wine .   deg. of vessel . differ . deg. of therm . diff. vibrat . diff. state natural         rise upon immer . abatement . ½ ½ ½ ½ rest ½   ½ remounting . ½ from the ½ deg. it visibly accelerated the motion of the level , and by little and little froze without any other motion in the vessel , the freezing of white muscadine .   the deg. of the vessel . differ . deg. of therm . differ . vibrat . diff. state natural         rise upon immer . ½ ½ abatement . ½ being come to that degree of without any rest or stop , it began to rise with a little swifter motion than we observed the liquors used to remount with , which freeze in the instant of that they exert their violent spring . when we took it out , we found the liquor began to have some ice next the sides of the glass . the freezing of distill'd vinegar .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural .         rise upon immers . abatement . remounting . spring upon glaciat .       which velocity was less than that of the freezing water , but considerably greater than that of muscadine , cinamon water , and simple vinegar . the freezing of the juice of limons   deg. of vessel . diff. deg. of therm . diff. state natural     rise upon immersion abatement when it was fallen to the th degree of the vessel , it began to rise again with a very slow motion , gently freezing . the freezing . of spirit of vitriol .   deg. of vessel . diff. deg. of therm . diff. vibrat . diff. state natural ½   ½       rise upon immers . ½ ½ abatement ½ ½ this liquor did likewise not rest at all , but being reduced to deg . began to remount in the neck of the vessel with a slow uniform motion , and at the same time shot it self in several planes of ice from place to place in the liquor , as is the manner of fair water set to freeze by it self in the open air . the freezing of oyl .   deg. of vessel . diff. state natural   fall upon immers . abatement     when it had contracted it self all within the body of the vessel it there congealed without the least rarefaction : for it may be the frozen oyl sinks to the bottom of the fluid , whereas all other ice swims upon their fluids . spirit of wine condenses extreamly , but never rarifies afterwards , nor affords any ice . experiments of natural freezing . although the freezings we have hitherto treated of , have been called by us artificial ; yet that takes not from their being the true works of natures own hand . now the same nature acting by other methods , and it may be with the onely ingredient of the air , we were curious to know , if any variety in the procedure of the operations , might be discovered in producing the same effects by other means . and when we already had this before us , we attempted to draw thence some other conclusions ; as will appear in the following discourse . the first experiment . of the freezing of common water in the air. it is already declared , in the foregoing experiments , that the artificial ice ( in the then described vessels ) proceeded from a beginning very soft , and incompact ; especially , in regard of those made in the winter air ; which , tho they are not so suddenly made , but begin from a thin coat , or hair-like vein , scarce discernable ; yet those veins , or coats ( excepting their brittleness , which comes from their being so very small ) are more firm , and hard bodies , and as it were more cristaline , and solid ice . and very admirable is that lusus naturae which for many years we have observ'd in natural freezings , viz. setting water taken out of the same spring in several vessels , as of earth , of metal , and of glass ; in the shape of tall glasses , or broad bowles , some part-filled , some quite-fill'd ; some open , others covered , and in several sorts of bottles , with different mouths ; some onely stop'd with cotton , others sealed at a flame , being all set in the same place undisturbed , or beside one another upon a table : sometimes that vessel which had least , was first frozen ; sometimes that which had most , and so in all the vessels , without any regard had of the form , or fullness thereof . as to the materials , we may positively aver , that earthen vessels freeze the contained fluid sooner than either metal , or glass . but as to the rest , we have found nothing so constant , as the perpetual irregularity of the accidents ; and among others , there have some vessels stood all night without the least coat of ice , when some next to them have been frozen in an hour . moreover , in the same sort of vessels set to freeze , in the same night , we have observed the like varieties , whether placed north , south , east or west ; and as well those vessels which have stood more southwardly have been frozen first , as at other times , those that stood more northwardly , tho the cold generally comes from that tract with us : and sometimes those eastward , sometimes those westward have got the better ; nay sometimes both have surpassed the north , and south , and at other times been vanquish'd by them . the method also observed in freezing , is very curious : the water begins first to congeal at the top round the edges , and from that list of ice shoots several small threads to the middle , after which it sends others downwards , and that indifferently from all parts ; by degrees these threads became ragged , yet thicker , and broader at one end , and more acute at the other , like little daggers ; from the sides of these shoot out other small threads close together like feathers , or palm branches ; these are as it were the first warping , and with a confused , and disorderly filling up , they proceed shooting and increasing till the woofe closes all with a total freezing of the water ; the superficies whereof may be perceived to be all raz'd , and full of strait lines , like cristal scratcht with a fine graver . at first the superficies of all these ices appears plain ; but when the freezing is throughly finish'd , and all the water congealed , it at last becomes raised in hillocks , but without any regular figure . this effect made some call to mind what was registred in our first experiment of artificial freezing , where the innermost cover of the silver vessel was found crack'd , and all coated over with a thin ice made of the water that got out of the vessel at the crack in the instant of freezing ; thereupon they said , that the first crust of ice which spreads it self over the superficies of the water , and shuts it closer than any cover can , by sticking fast to the sides of the vessel ; does not leave space enough for the water under it to rarifie in , as it freezes , but it is forced to seek room where it can ; and finding the cake of ice weaker than the sides of the vessel , it makes its way there , and heaps it self up more in one place than another , according to the inclination of the plains in which it breaks , when the first cake splits , which afterwards likewise freezing , forms that little swelling mentioned : this happens sometimes to break the vessels , which ( as they think ) is most probably caused , by the slowness of the waters freezing at the bottom ; whereby the cake of ice at the top becomes so hard , that it is easier to break the sides of the vessels than the icey cover : but no certain rule can be given concerning these matters , since there may be many cases wherein either the vessel is onely burst , or the cover onely : or first one , then the other ; or both at the same time , according as the external accidents of the air vary ; as to cold , calmness , or winds ; and from the inequality of the vessels resistance , or from the nature of the liquors themselves . before we put an end to this discourse ; it will not be amiss to relate a trifling accident observed this year , which though of small moment , may nevertheless be some help to the former opinion . a cup of water being exposed to the air in the evening , we found in the morning all the water frozen ; and in the highest part of its superficies it had a point of ice a finger high , like a small sharp splinter of rock cristal : this in all likelihood was no other than the water issuing out at a crack in the first incrustation , being forced by the freezing , underneath , which violently rising in a small stream , ( and predispos'd to freeze , ) by the cold of the external air , was congealed to an hard ice , in that very instant , not having time to fall . the second experiment of the freezing of water in vacuo . we have likewise tryed to freeze water in a vacuum made with mercury : and that we might compare it with that made in the air , we put water in a vessel like that included in the vacuum . therefore exposing them all night , we found in the morning both frozen : yet with this difference ; that the ice made in vacuo seemed more equal and hard , and less transparent and porous than the other ; and upon examination , was heavier in specie . the way we took to discover this , was by turning a piece of each ice like a cilinder , and of the same bulk , as near as we could , and putting them in spirit of wine , upon which gently pouring some red wine , we saw the ice made in the air rise up before that made in vacuo ; and when upon the top of the water , it swam about lighter , and quicker because the fluid covered less of it , than of the other . the third experiment of the freezing of still'd water . having set common still'd water in several vials to freeze , we found the ice more limpid and transparent than usually the water is : onely in the midst there was as much as a small nut of a more opaque ice , and whiter than the rest , and round about it divers spiculae of the same kind of ice : in fine , to give a true picture of it , in each vial 't was like the burre or husk of a chestnut , frozen in a piece of rock-cristal , as we see flys , worms , or butter-flys entombed in amber ; or like little bits of straw , herbs , &c. in cristal it self . the fourth experiment , of the freezing of sea water . to see the freezing of sea water , we exposed one evening to the air ( when a thermometer of deg . stood at ° , two glasses full of it , to freeze : in an hour we found the shallowest began to freeze ; but in a manner somewhat different from common water ; for it shewed like a great many small scales of talke broken to pieces , and put in water . these took away the trasparency of the water , and gave it the consistence of sherbet , which is drank frozen in the summer , when the externally applyed snow growing more languid , it begins to dissolve . in a while looking upon it again , we observed it a little firmer , as the multiplying of the scales lessened the fluidity of the water ; in the morning it was yet harder , tho it came nothing near the hardness of common ice ; for upon any little agitation , it turned to water : the figure of the scales was narrow , and longish , and between them it was for the most part fluid : moreover , the mass stuck no where to the sides of the vessel ; but turned freely about in it . the superficies was altogether plain , without any prominences , or risings : and the difference consisted wholly in a more loose and thin order and texture then that of ordinary ice . the fifth experiment , of the efficacy of sal-armoniac , nitre , &c. in freezing . it is well known , that ice is most efficaciously cold when sprinkled over with salt. as to this we have observed , that sal-armoniac invigorates it more than any other ; for we have experimented it upon the same water , of the same temperament , and in like vessels of the same figure , capacity , and thinness , equally encompassed with the like quantity of beaten ice , and the one being sprinkled with sal-armoniac , the other with the same proportion of nitre , they were not frozen in the same space of time : for a thermometer of deg . being ( when it stood at deg . ) immersed in water set to freeze with nitre , subsided but to ½ deg . when at the same time a like thermometer put in water , encompassed with the mixture of sal-armoniac , fell down to deg . and the water began to be skinned over . we have already said , upon another accompt , that not onely salt , but strong-waters wonderfully intend the freezing ; and if besides the strong-water , you add salt , it will prove most powerful : nay , sugar produces such an effect , but not much in comparison of common salt , nitre , and sal-armoniac , which we found much more successful in the operation of freezing , than all the rest . the sixth experiment . touching what metal preserves ice best . putting ice in vessels of several different metals to observe which kept it the longest unthaw'd ; yet , of this we could obtain nothing certain , tho we may say at large from a very great number of experiments which we made , that it was preserved best of all in lead , very well in tin , but a short time in copper , and iron , less in gold , and yet a lesser time in silver ; nevertheless , at sometimes this order was changed , it melting sooner in tin and lead , than in silver and gold : wherefore ( as we hinted ) this experiment is not to be much confided in , but proposed here rather to excite others to attempt it by some more secure way , than to shew any certainty we obtained in our observations . the seventh experiment of freezing a piece of ice to a table . gassendus writes , and it is very true , that if a plate of ice be laid upon a flat table , and well sprinkled above with salt , it will freeze fast down to the table : we were desirous to make the same experiment with nitre , but it succeeded not , so as to shew us the least beginning of adhaesion : we have often observed in those stuck down with common salt , that we much more easily separated them from the table , by lifting them up perpendicularly ( or at one end first , as a board nailed down is raised up with a lever ) than they could be forced along parallel to the plain ; moreover , the water on the under-side of the ice was salt , and that side also thereof was opake , and covered with a white hoariness made of innumerable small particles of salt : and brought to the light , it appeared rough , as if it had been prettily razed with the point of a diamond ; like the glass of those vessels , which from the artificial similitude they have to ice , we call ice-glasses . the eighth experiment . of freezing the dew upon the outsides of vessels . that dew which covers the outsides of glasses , containing any cold liquor , or ice , is sometimes observed to congeal there : and the same happens , when the ice or snow in the vessel begins to alter with the strong water or salt : there is also an exhalation , or cloudy moist vapour rises up as it seems from the bottom of the vessels , whence proceeds a very cold air , which besides that it sensibly affects the hand , is likewise more discernable , by the agitation which it causes in the flame of a candle brought near it . this experiment we repeated , by putting ice sprinkled with strong water and salt in several vessels of different figures and metals ; to observe if either the one , or the other afford any variety in the smoaking : and as to the materials , we could not perceive any diversity , whether the cups were of glass , earth , wood , metal , or precious stones . but as to the figure , it seemed to us , that whereas in beer-glasses , and all other tall , narrow vessels , the smoak began above , on the contrary in wide bouls it smoaked from the bottom freely upwards for a short space . in a golden boul , we observed an effect which ought to be vniversal in all vessels , tho it is less observable in some by reason of their shape : it was this ; when the smoak ceased , that crust of ice began to let fall after the manner of dew , a fine ice , like poudered glass , and continued till the ice in the boul being dissolved , that thin outward covering likewise melted . the exhalation said to proceed from the ice seems very different from that of any combustible matter , and much resembles the morning mists that rise from the earth . the ninth experiment . of reflected cold. we were willing to try , if a concave glass set before a mass of l. of ice made any sensible repercussion of cold upon a very nice thermometer of deg . placed in its focus . the truth is , it immediatly began to subside , but by reason of the nearness of the ice , 't was doubtful , whether the direct , or reflected rays of cold were more efficacious : upon this account , we thought of covering the glass , and ( whatever may be the cause ) the spirit of wine did indeed presently begin to rise ; for all this we dare not be positive ; but there might be some other cause thereof , besides the want of the reflection from the glass ; since we were deficient in making all the trials necessary to clear the experiment . experiments , touching an effect of heat and cold , lately observed as to the alteration of the inward capacity of glass , and metalline vessels . we said in the experiments of artificial freezing , that the first motion observed to be made by the liquors ( exposed in vessels to freeze ) was a small rising up , there called rise upon immersion ; because it happens upon the vessels first touching the freezing mixture : and you must know , the contrary to this is observable , when it is immersed in hot water ; for the levels of the contained fluids sensibly subside , and then ( as it were ) take time to rise again , which they do with a quick spring , up to the degree they stood at when first immersed in the hot water , and thence successively rise , as the heat received continues to rarifie , lighten , and raise them . on the other side , tho they are raised upon the first immersion into cold water , or ice , yet they not onely subside again to the former height , but continue to do so for many degrees , till at last ( sometimes after a little rest , sometimes without any ) they all remount ( oyl , and spirit of wine excepted ) until the whole freezing is finish'd . this effect was by some attributed to a cause much favoured by several following experiments : their apprehension was , that the appearance of this sudden motion in water , and other fluids , was not really from any intrinsic alteration of rarity , or density at that moment wrought in their natural temperament by the power of any tab. . p. . contrary quality of the outwardly applyed ambient , which some by a noted word call antiperistasis ; but rather , ( to speak first of the subsiding upon the immersion of vessels in hot water ) their thoughts are , that it comes from the fixing of several volatile corpuscles of the fire , ( evaporated from the hot water ) into the external pores of the glass , which as so many wedges , forcing , and separating the parts thereof , must necessarily distend , and enlarge the internal capacity thereof ; till they find a way through the hidden passages of the glass to the liquor therein contained . that on the other side , cold binding up , and contracting those pores of the glass , makes the vessel become too scanty for the bulk of water in it , before that bulk of water , yet unaffected by the cold , contracts likewise . in fine , that the vessel being first sensible of cold or heat , by shrinking or enlarging it self also first , is the true cause of that phenomenon of the rise or fall ; as it becomes more strait , or large to the contained liquors , yet not vitiated by the quality of the ambient . this opinion was rendred more probable to us , by the following experiment . an experiment , proving , that in the instant that the external heat or cold dilates , or contracts the vessel ; yet then the natural temperament of the liquors therein contained is unaltered . we included in a globe of glass filled with water , several small bubbles of coloured glass , empty , and sealed hermetically : these were all near the specifick gravity of the water , by means of the air they had in them ; whence the floaters upon the top of the water upon the least breath of warmth sunk down , and those at the bottom , upon any accession of cold , mounted upwards : hanging this instrument in the air , and suffering the bubbles to rest , we began to approach to it underneath a pan of water heated , and after that of cold water mix'd with ice well broken ; and though upon the application of these different ambients , we observed the same effects in the level , of raising it self upon the touch of the cold , and subsiding upon that of the hot water ; yet we could not find , when the water seemed condensed , and contracted , that any of them at the bottom rose up , nor when the water seemed rarefied , and enlarged , any of the floaters sunk to the bottom : but these were observed to fall , and those to rise , when the water after its abatement upon the first impression of heat , began to rise again , and when after its rising upon the impression of cold it began to subside again : an argument to insinuate , that , the water , and so any other fluids in this first motion , do not really move themselves , but onely obey the alteration of the vessels they are contained in . yet it may be objected , that these first alterations did really proceed from the inward changes of the liquors , which tho discernable by the eye , by means of the small neck of the vessel , yet were not great enough to be discerned in changing the aequilibrium of the bubbles ; of which it may be thought , that , in that very instant , they began really to move , though in their first parting from rest , the eye could not perceive it . to this is answered , that , the true rarifaction , and the true condensation of the water ( that is able to make it rise or fall so very little a space as it does rise or fall at the entrance into the icey mixtture , or hot water , ) is sufficient to alter the aequilibrium also between it , and the bubbles , apparently to the eye . and indeed , when the water really rises or falls from a true rarifaction or condensation , the bubbles likewise begin correspondently to move , before ever it comes to the same degree , at which ( the same bubbles remaining immoveable ) it stood at the instant of its first immersion . nevertheless , the discovery of this effect ought not to cause in us the least scruple of the truth of our thermometers ; since the whole contraction or dilatation in vessels containing an ounce and half , at most amounts but to a grane ; whence proportionably how small will that be in vessels of a few granes content , such as our thermometer of deg . which are the most convenient , and exact , and upon that account most made use of to discover the alterations of the air ? now to manifest by divers ways , even to sense , the truth of this phenomenon , we made the following experiments : which first founded in the theory , are confirmed by the effects . the first experiment , shewing the alteration of the size of a brass-ring put in the fire , and in ice , its figure still remaining unaltered . there was ordered to be cast a ring of brass , and by turning it was fitted exactly to a cilinder of the same metal : this was put in the fire for a short space , and then being put upon the cilinder while hot , it was sensibly loose ; being dilated by the heat into a ring of the same shape it was of before , but its concavity was / parts larger : when it had remained some time upon the cilinder , and had communicated its heat thereto , between the increasing of that , and the shrinking of the ring by little and little as it cooled ; they not onely came to fit as at first , but were so firmly united , that before they were quite cold , a considerable force was but requisite to separate them . the contrary in all respects happened when we intensly froze the ring . the second experiment , whereby it appears that bodies are dilated by the imbibing of moisture , as well as by the insinuation of heat . we made a conical ring of box , whose concave superficies was curiously turned , and polish'd : there was also made a stock or conical mandril of steel turned , and well smoothed , and nicely divided with many circles parallel to the base : fitting the ring upon this , we marked which of those circles the bottom thereof just touched ; taking it off , we let it lye in water three whole days ; that it might have time to penetrate through the whole stubstance of the wood ; then we put it on again , and observed , that the concavity was stretch'd , the bottom of the ring falling much lower upon the stock , than it did at first . this ring was made two several ways , in one the ligneous fibres were perpendicular , in the other parallel to the plane of the basis ; the first after soaking in the water kept its spherical figure exactly , the other came near to an oval , and put upon the stock sunk down much short of the former . observe to make these rings of firm , clear wood , that is without knots , and of an uniform hardness ; especially , when the fibres are cut transversly ; that so all being swell'd by the steeping , their enlargment may be the more sensible . note also , ( as was said at first ) that the rings must lie so long in the water , as their whole substance may be penetrated : for the effect will be different ; if those that are but a little soaked on the outside , be put upon the stock ; because they will not slide down so far , as when they were dry . therefore let them be well impregnated , and satiated with moisture , that their dilatation may be the more visible . the third experiment , which discovers more evidently the readiness of glass to contract and dilate it self upon heat and cold. there was made a hollow ring of glass ( as in the figure ) about two foot in diameter , with two funnels , that when the liquor was poured in at one , the air might have vent at the other : then was made a cross of glass just to touch with its extremities the concave of our hollow ring , and filling the vessel with hot water by the funnel , as it proceeded in dilating it self ; so visibly , either the one , or the other of the glass rods lost their hold ; for they did not bear equally stiff against the instrument , and at last both were loosened ; so that the cross being at liberty , fell down upon the table whereon we set the instrument , within the circumference of the ring . after this , pouring the hot water out , we fill'd it with a mixture of salt and ice dissolved ; and it not only held the cross again , but with greater firmness than at first . the fourth experiment , to find the same effect in metals . having bent a small plate of tin like a stirrup , and hung it up , so as the two extremities might touch a plane put under them , upon which we drew two lines , where the aforenamed extremities must necessarily strike , if they had been prolonged : we then put a live cole over the bending of the plate , and attentively observing one of the points , we discerned , that by little and little it parted from the line drawing within it ; and this was when the convex of the plate onely being heated , dilated it self , and the concave was contracted : but when it had penetrated ( which it soon did ) the whole thickness of the tin , being then equally dilated , the point not onely again reacht the line , but passed beyond it , more or less in proportion to the heat communicated by the fire to the bending of the stirrup . the fifth experiment , to observe by the sound the like dilatation in a stirrup of glass . we fitted a minikin to a broad stirrup of glass , as in the figure , and tuned it an octave to the string of a guitarre , and applying the heat to it after the same manner , as we did to the stirrup of tin , when it had not yet affected the concave superficies thereof , but onely the convex , tab. . p. . the tone was flatter , because as in the foregoing experiment the aperture was lessened , and consequently the string slackened ; but when the heat had penetrated quite through , the string was straitned so , as the sound was sharper than the first tuneing . the sixth experiment , discovering the same effect more clearly to the eye . we fastned to the same string with a bit of thread , a small leaden plummet , and put under it a little plate of glass , so as not quite to touch the weight ; and applyed fire to the usual place : the effect as to the stirrup was the very same as at other times ; for being at first drawn together , the cord became slacker , and the weight rested upon the plate of glass ; but at last extending the aperture , it strained the cord , and raised up the plummet ; the contrary effect was wrought by ice made use of instead of the coal , but sensibly less , in proportion as its activity is less ; than the fires . the seventh experiment ▪ shewing the same effects in wire strings . a leaden plummet being fastened to a nealed brass-wire , and hung over a glass plate , at a little distance therefrom , drew nearer to touch it as the wire became heated , by applying a lighted candle to it , and still retired from it upon every little rubbing with ice . in like manner , two wires of mixt brass tuned unisons , so that one being struck , the other sounded , were made discordant , either by approaching to one of them a live coale , or a piece of ice , that by lengthening the wire made the tone flatter ; and this by shortning it , sharpened the sound thereof . the eighth experiment , whereby from the appearance of a contrary effect 't is confirmed , that the first motion of liquors comes from the capacity of the vessels being altered in the instant of immersion . it may happen upon the first immersion of vessels into the ambient hot or cold body , that the level of the contained liquors shews a different effect from that before-named ; that is , that it may immediatly rise in a hot ambient , and subside in a cold one : this will be always if the vessel be made in the shape represented by the figure ; in this upon the first touch of warm water , the liquors will presently rise , because ( in the lateral angles , being very strong and thick of metal in comparison of the hollowed faces , ) the heat acting , first upon the outward superficies , lessens those angles ( as we said before it does to the stirrup of glass ) and so necessarily comes to stretch the thinner hollowed parts , which dilating inwards , happen at first to lessen the capacity of the vessel , and to raise the liquor in the neck : which falls again from that space new filled , when the heat has penetrated the whole substance of the glass , and the vessel begins to enlarge it self uniformly , returning to its first size , and larger ; and at last the liquor rises again , when impregnated with the fiery corpuscels it begins to rarifie . and it is manifest , that the contrary to this , is observed from cold , the same causes acting contrarily . and note , that the capacity of the vessel was lessened , by the pressure of the hand onely , made upon two opposite hollow sides ; nor could the rising of the liquor be attributed to the heat of the hand rarifying it ; for it was raised after the same manner , by pressing the vessel with two pieces of ice . the use of the next instrument may easily be comprehended from its figure ; being onely a plate of steel , perforated with circles of divers measures to observe the different increasings , caused by different degrees of heat given to the same , or several conical rings of metal . the ninth experiment , to shew , that a vessel may be distended , not onely by heat , or by soaking up of moisture , but also by weight . there were made two vessels of glass , the one conical , the other pyramidal ; and letting them into a thick table , we marked round the outside of the vessels how far they sunk down ; then taking them out , we fill'd them with mercury , and put them again into the holes in the table ; but they would not go down so low as the mark made at first , because they were distended by the force of the mercuries weight ▪ experiments about the compression of water . that experiments do not always reach the truth aimed at , is not from any defect of the idea conceived of them in the mind ; but rather happens from the necessity we have of material bodies , and corruptible instruments , to put our conceptions in practice ; which though of themselves unable to blemish the theory and speculative part , yet through the defaults in their substances , are not always capable of seconding our thoughts : but we must not hence conclude , the experimental method fallacious in the quest of natural events : for though by it we may sometimes come short of the very depth of that truth , which we first sought after ; yet it is hard , if it does not give some glimmerings and marks to discover the falsity of any contrary supposition . this has been our fate in our research , whether water can suffer any compression , as air does ; in which attempt , for as much as the weakness of our vessels came short of affording us a perfect knowledge of the truth , we making use of glass ones as most fit , because of their transparency ; yet at least we gained this much , that water cannot be compressed with a very great force ; and so far we have proceeded , that a power able to reduce air into a space times less than what it first filled , that power not onely thirty times , but a hundred , nay perchance a thousand times encreased , was too weak to compress a quantity of water a hairs breadth , or the least visible space from its natural extent ; the methods we took were those that follow . tab . . p. . the first experiment . let there be at the ends of two glass canes ab , ac ; two balls of glass also , the one larger than the other ; fill both with fair water to d , and e , and joyn them together with a lamp , remembring to leave a passage open in sealing them at a , and to draw the beak af very long , and open ; then apply to each ball a glass full of beaten ice , burying them therein , that by condensing the water there may enter as much air as possible into the canes ; and the better to force it down , you may rub a piece of ice backward and forward upon the out-side of the syphon dae , which by its coldness contracting the air in the canes , there will enter in more to fill it at the beak f ; then seal it at a flame , and the contained air will remain prest and thronged together ; after this as it is sealed , take the ball b out of the ice , and at first immerse it in tepid water , next in warm , and at last in boiling ; keeping the ball c all the while covered with ice , to reduce the water therein to the utmost condensation , which suppose to be at e ; moreover , indeavour to compress the cilinder of air ge to its greatest density by the force of the water rising to g , being rarified by the received heat from the water supposed to boile round about the ball b ; now if the water could suffer any compression , it ought to subside from the pressing air below the mark e ; but with us it still happened otherwise ; for when the water at e was once reduc'd to its utmost condensation by the cold , &c. the force of the air ge pressing thereon , was unable to gain a tittle , and did sooner burst out the bottom of the ball c , than force the level e a jot ; and when to add a greater strength to the instrument we made the two balls of copper , the water in the ball c has sustained the force between the air pressing at e , and solidity of the metal with insuperable resistance , rather bursting the syphon , ( which must be of glass to discover the internal motion of the water ) joyned fast to the copper with mastick , or the usual hard cement . the second experiment . let there be prepared a vessel of glass ab , contained about l. of water , the mouth large enough to receive a glass cane bound close about with lead to keep it from bursting : fill this vessel with water up to cd , immersed the cane ef open at each end therein , and soder it close at a with the usual cement , remembring to lift up the lower end a little from the bottom of the vessel fb , that the liquor poured thereinto , may have free passage into the vessel : then begin to pour quick silver down the cane into the vessel , raising up the water , 'till the vessel is quite full ( the air having its exit at the beak h ) and to be certain all the air is gone , let some water out at the beak h , and immediately seal it with a flame ; noting , at the same time , the degree the mercury stands at in the vessel ik : afterwards , pouring in more mercury , fill the cane to the top ; then if the water by this force is compressed , the height ik will gradually encrease , as the water yields : we by a charge of l. of mercury , in a cane above inches long ( for so much our instrument held without cracking ) could not perceive the level ik raised an hairs breadth , the water obstinately resisting the force of so great a momentum . the third experiment . we ordered a thin large vessel of silver to be cast , and filled it with water cooled very well with ice , and screwed the cover on with a very close screw ; then we began to hammer the vessel gently every where , and the battered silver ( which being so little ductile did not at all thin , and distend it self , as refin'd gold , lead , and other soft metals do ) lessened , and comprest the inward capacity of the vessel by degrees ; yet the water for all this suffered not the least compression ; for at every stroak we perceived it to sweat through the vessel at all the little pores of the metal , as quick-silver when pressed with a piece of leather spirts through in little drops . this is what we thought worth relating of these three experiments ; but are not yet able to say , whether , if the same experiments be repeated in vessels of greater strength , and if the rarefaction of the water be augmented in the first experiment , and so the pressure of the air ; or if the height of the mercurial cilinder be increased in the second ; or if in the last , the vessel be successively made of thicker silver ; i say , we are not positive , whether the water may not at last happen to be comprest ; this is certain , that water in comparison of air resists the compression ( we may almost say infinitely ) more : which confirms what we said at the beginning of these experiments , that if experience does not reach the very bottom of the enquired truth , yet it goes hard if it strikes not out some light. experiments to prove there is no positive levity . ancient , and famous is that question , whether those bodies that we usually call light , are so really in their own nature , and mount upwards from any proper tendency ; or whether their motion be no other than a chase , or flight they are forced to by more heavy bodies ; which having the greater force , and desire to descend , and place themselves undermost ; press , and as it were , compel the other to rise ? this opinion , which chiefly seems to have been entertained in these latter ages , was yet not unknown to the ancients : nay , it was asserted from rational grounds by many philosophers in those times ; among the rest clearly by plato in timaeo ; and he advanced so far upon the probability of that thought , that he not onely holds , that the heavier bodies force up the less heavy , as fire does air : but also the more heavy , as water in respect of air , when ever it is made lighter by the interspersion of fiery particles : and this he seems designedly to insinuate in the above-cited dialogue of timaeus , when he says , that the fire rising from the hot entrails of the earth , and not entring into a vacuity , thrusts forward the air that is contiguous to it ; which not onely gives way thereto , but even divests it of those moist particles wherewith it ascends ; and then helps it forward , and raises it up unto the seat of fire , and that by no other , than by the natural gravity of those humid parts , being ( by means of the coalition with it ) attempered by the new acquired levity : however this may be , in confirmation of this opinion , we will produce onely two experiments , whose weight may perchance make up the deficiency of their number . tab. . p. . the first experiment . let there be a cilinder of wood abc , whose base bc exactly touches the horizontal plane de ; and that the ambient air getting between the two superficies's , may not hinder the trueness of their contact , let the base of the cilinder be lined with a plate of metal plained , and well polish'd , and another like piece leaded into the horizontal plane , then making a ridge with wax , or plaister round about the cilinder , pour mercury into the trench up to f , that the contact may be every way covered and hindered from the ingress of the air : then fasten the end of the cilinder a to one of the equal arms of a beam gh , whose center is i ; at the other end h , hang the weight i , equal to that of the cilinder abc : it is manifest to sense ▪ that to raise the cilinder from the plane , the weight l is insufficient , but several weights must be added to the end h , till at last ( suppose ) l and m raise it , resisting now with a double force ; that is , with that of its own weight equal to l , and with that of the contact , or repugnance to vacuity , or what else it may be termed . the superadded weight m must not onely equal , but exceed the power of the said superficial contact . to measure this force ( which in our instrument was about l. ) put the cilinder into a cilindrical vessel of wood , or potters clay glazed nop , of an equal , or greater height therewith , that the base of the cilinder may touch exactly the plane of the vessels bottom ; let that also be covered with a polish'd metal or ground glass . then pour quick-silver into the vessel np , to what height you please , even to the top of the cilinder , which will never separate it from the bottom ; but if with the hand you move the base bc from the plane op , it will with great force rise up , and swim upon the quick silver . seek then how great this raising power is , supposed to proceed from lightness ; by us 't was so found : we loaded the top of the cilinder a with so much weight q as would sink it to the bottom : which weight in our experiment being about l. we concluded , the force enquired to be so much : next we considered , that the resistance of the contact of the superficies's was no more than l. ( as was said ) and the force of the supposed levity of the cilinder was found to be l : wherefore in this case , that of the levity was more than that of the contact : wherefore again , considering the cilinder of wood ab closed down with its base bc to the plane op , there were then two contrary powers acting ; viz. that of l. from the levity to raise it ; and that of l. from the contact which held it down : now the lesser force ought to yield to the greater , and so the cilinder be raised : but it was not so here ; for the contact was not loosed : wherefore it seems we must conclude something besides levity buoyed it up . the second experiment . let there be a wooden vessel abcd , in the thickness of the bottom whereof a concave hemisphere is turned efg , exactly fitting a ball of ivory h , adapted to its greatest circle eg ; then the whole vessel was filled with mercury , so that the globe was quite covered therewith ; it is manifest , that the weight of the mercury incumbent upon the bottom of the vessel , and hindred from running between the lower convex of the ball , and concave of the vessel by the closeness of the contact at the circumference eg , was not able by descending thither to raise the ball by pulsion , but the natural levity of the ivory , if there be any such thing , might easily buoy it up in the heavy ambient of the quick-silver . but this did not follow ; the ball remaining unmoved in its socket under any height of mercury . nor can it be objected , that natures avoiding a vacuum ( which must follow upon the first loosening of the ball from the concave of the vessel ) hindred the natural levity of the ball from its effect ; for though we made an hole thorough the bottom of the vessel fi , whereby the air had admission to fill the space left void upon severing the ball ; yet for all this it was not raised . and because it may be said , that the ball being touched by the air below , is not lighter , but heavier than it ; we again stop'd up the hole , and enlarged the socket ( as it appears ) elg , so that onely the edge , or upper circle of the hole eg remained equal to the greatest circle of the ball ; but the hemisphere efg was not now fitted to the concave elg , as is plain in the figure : we then filled elg with mercury , and forcibly thrust down the ball till its greatest circle touch'd the edge of the concave : now tho it was but slightly held by the circle eg , so that with a very little force it might be turned about ; yet we fill'd up the vessel with mercury , and it was not raised , nor moved . lastly , that it might not be suspected , that the mercury poured on , by pressing upon the ball , held it down with its weight from swiming ; we took instead of the ball h a conical glass vessel abcd , and fitted a lesser circle thereof to the edge ef , and pouring mercury round about it , it kept still unmoved : and to be satisfied , if the supposed tenacious vnion between the glass , and the mercury , together with natures fuga vacui , were able to surpass the power of the glasses levity ; we tryed the force of that contact by taking away the mercury from about the glass , and fastening of it to the one terminus of an equal ballance gh , hanging a weight i at the other h , till the glass was loosened from the socket ef , which weight was with us about a pound ▪ then filling the vessel again with mercury , we set the glass to swim therein , and loaded it ( as in the other experiment ) 'till it sunk it to the bottom , and kept it there : this weight ( which with us was about ½ l. ) may be the true measure of the momentum , believed to proceed from the levity of the glass abcd , which is more than that whereby it resisted a vacuity which was but one pound . then if the lightness is that which causes the glass to swim , it would have produced its effect , dissolving the contact , since its force is much greater than that of the contact resisting it : but it does not do it ; therefore it seems , that the same is confirmed by this second experiment , which was concluded from the former , viz. that it is some other cause besides the levity , that lifts up the ivory ball , and the glass vessel . experiments magnetical . altho the strange effects of the magnet are so boundless an ocean , that tho many discoveries have been made thereon ; yet 't is probable , enough remains to satisfie the labour and curiosity of future adventures : yet we have not hitherto been so hardy to launch forth into it ; well knowing , that any thing new therein , requires a long application , and uninterrupted by other speculations : wherefore we would not have it thought by any , that with two or three observations upon this subject , we should be so vain to boast , that we have brought any light to the magnetic philosophy ; for we rather own , that these hints are mean enough , and it may be not altogether new , being such as have not been aimed at in a designed application of our endeavours magnetical ; but either have been accidentally found out , or sought after upon some particular end by some one of our academy . but such as they are , we were unwilling to conceal them ; our intent being to communicate all that has any agreement with truth , tho of but little value . the first experiment , to discover if ( except iron or steel ) there be any solid , or fluid body , which interposed between the magnet and iron , will cause any variation , or quite cut off the passage to the magnetic virtue . at one end of a wooden box abcd , we fixt a compass , and opposite to the dart ( respecting the point e ) at the other end of the box , we moved a magnet , and gently approaching it nearer till the dart was removed one degree , that is , from e , to f , we there fixt the load-stone , and in the space remaining between it , and the compass , we set either glasses filled with mercury , or wooden vessels filled with sand , or fileings of metal , ( except of iron , or steel ) or solid parallelipipid's of the same metal , or of divers stones , and marbles ; but still we found the dart unmoved from the point f. lastly , we filled the same vessels with spirit of wine , and set it on fire , yet that flame did not in the least divert the power attracting the dart to f : and a thin plate of iron or steel , onely was able to vary it , and make it return to e , as is already known . and not onely the above-named causes were unable to obstruct the magnetic activity ; but we have laid upon one another pieces of gold , and laid a needle upon the uppermost , which has obeyed the motion of a magnet , moved under the lowermost . tab. . p. . the second experiment , to shew yet more nicely , whether the magnetic virtue suffers any change by passing through divers fluids . we hung upon a small stick cross a glass vessel ab , a needle touched with a loadstone , and in the bottom of the vessel placed a little cilinder of lead ; upon the upper surface thereof we fix'd two points of brass , ( they may be of any metal but iron ) one placed in the center , the other the breadth of a crown off it ; then we adjusted the needle exactly perpendicular to that in the center , and placed the magnet at such a distance , as not to move it ; then we gently approach'd it toward the needle , keeping the pole still direct upon it ; which to be certain of , we slid the stone with one of its sides along a ruler cd fix'd in a frame , and levell'd exactly upon the two points , whereof that which was not in the center respected the pole of the magnet , as well as that which was : coming nearer and nearer , at last its virtue began to act upon the needle , which sensible of it , moved softly toward it . the observer did not rest there , but thrust the loadstone a little forwarder very slowly , till the point of the needle reach'd to the second brass pin , which was nearer to the load-stone : then he stop'd , and gave a mark upon the rular , at the distance between the magnet and needles point , which was just over e. after this , the magnet was removed , and fair water poured into the vessel about the needle , and the operation was repeated as before , by approaching the stone gently till the needles point touch upon e ; and again , the distance upon the rular was marked : and throwing out the water , 't was reiterated with several fluids , the distances being taken every time between the point of the needle and magnet : from all which it appeared , that the magnetic virtue was neither weakned , nor enforced by the differing fluids through which it passed : indeed the distances were divers , but that happened according as a lighter or heavier medium facilitated more or less the motion of the needle in it ; whence the same virtue and power moved it at a further or nearer distance ; for 't was observable , that those several distances at which it acknowledged the loadstone , were in reciprocal proportion to the specific gravity of the fluids ; that is , to the making the needle lighter . amongst all the liquors experimented , the needle was drawn at the greatest distance in sea-water , at a lesser in common-water , lesser in spirit of wine , and least of all in the common medium of air. note , that repeating this experiment at several times , it may happen , that this distance varies at one time from another ; but it is to be considered , that this may arise from external accidents , viz. the different temperature of the air , a rustier or brighter needle , or the fortuitous nearness of some iron , which makes the direction of the magnetic virtue to deviate some way or other , &c. wherefore we still took care to make this experiment upon a large table glewed together , and fastned with wooden pins instead of nailes : and the observer ( and every body else that came near ) was very careful to lay aside any iron they had about them , it being well known , that to approach the table with a key or knife in their pocket , immediatly caused an alteration in the experiment ; but when all sort of iron was laid away , the effect was always the same : but for what depends upon the other fore-named accidents , such as the temperament of the air , and the like , which cannot be helped ; we have found , that they do indeed cause some difference in the distances ; that is , the distance whereat the needle was moved yesterday , is not the very same to day , in the same mediums ; yet the differences observed at these divers times , were still found nearly proportionate to each other . the third experiment , to try if the activity of the poles of a magnet alters , being placed respecting the opposite poles of the earth . tho in this experiment we have not yet proceeded so far , as to satisfie in order the many particulars depending thereon ; yet in general we will touch upon those few which we think we may aver upon any more certain grounds ; as these : the north pole of the magnet when respecting the same pole of the earth , draws a needle hung freely in the air , at a greater distance , than when it respects either the south , or east ; placed westward , its sphere of activity is larger than southward , and a little less than northward . on the contrary , the south pole not onely seems to us , to act at the same distance southward , as the north pole northward ; but also in a north position happened to draw the same as it did when southwards ; towards the east or west it becomes more faint and languid , as the north pole does also . experiments , touching amber , and other electric bodies . the electric virtue , as all know , is excited by a slight , or violent rubbing in all substances not mineral . yellow amber is of all others best stored with this power : next to which , the best sealing wax seems to take place ; these are followed by rose diamonds , the white saphire , the emerald , the white topaz , the spinelle , and the ruby baleis ; after them , are all the transparent gems , as well white , as coloured ; all which , more or less shew themselves to be attractive . and in this it does not seem , that they keep any scale or proportion in respect of their hardness : for we find that the soft spinelle and ruby-balleis , not at all to give place to the hardest diamond , or saphir , in electricity . next precious stones , come glass , cristal , yellow amber , and black ; between all which bodies , there is little difference of force , they being all very weak in operation . for the rest , neither lapis lazuli , turquoise , jasper , agate , nor other the like precious stones not transparent , nor rocks , nor the finest marble , nor marine bodies , as coral , and pearl , nor metals , nor cristalized salts , have any attractive virtue , as some have wrote they have ; and it may be the mistake came from their observing some light bodies , as bits of straw , and paper , &c. stick to them , which we have also observed ; but perchance that might happen ( as some think ) from a superficial roughness , or inequality in the substances , whose points piercing the light bodies , raise them up therewith : willing to avoid this cheat , we resolved to attribute electricity to no substances , that after a due friction did not attract those light corpuscles at some small distance , which we onely found done by the above named . we have also noted , that whatever external accidents alters amber ( whether by heating , or freezing , or wetting with any liquor ) the same has the like effect upon gems , and all other electrick bodies : yet indeed it is more manifest in amber , as it is impregnated with a greater virtue : wherefore omiting all others , we will here onely treat of that . amber then , of all sorts of bodies presented to it , refuses onely to draw flame ; altho plutarch says , that it does not attract any thing steeped in oyl , and grease ; or as some say , basilicon , which we found a mistake : yet smoke is attracted ; and it is very curious to observe , how by holding a piece of amber rubbed hot , to the smoak of a candle blown out , it will presently bend , and wave towards the amber ; part of it will be arrested by the amber ; and part , as if reflected from a glass , will mount upwards , while that which remains , unites it self like a small cloud , and as the amber cools rises in smoke again , and vanishes . on the other side , flame , not onely refuses to yield it self ; but if a piece of amber , after it is well rubbed , be a little while held to it , it loses its virtue , and a repeated friction is but necessary to make it attract ; and if after it has taken up any small thing , it be held to the flame , it will immediatly let it go again . but the heat that comes from burning coales , is not so great an enemy to the power of the amber , it being sometimes capable of exciting it without rubbing , and indeed by the heat received from the fire onely , it acts faintly ; but then becomes more vigorous , by adding friction thereto . ice alone is not prejudicial to the amber , but when altered by mingling therewith salt , or aqua vitae , it so quells the virtue , that some time is required , as likewise a long and violent rubbing , to regain it . so that it has been thought , that this stupifying of its force proceeds not from the increase of cold in the ice , from the sprinkling of salt , or aqua vitae ; but rather from some fine rust , or hoariness , as it were , contracted by the amber , from the salt ; or rather indeed , from the imbibing the aqua vitae , which is one of the liquors that destroy the electricity of amber . neither are all matters capable to draw forth this virtue from the amber ; for being rubbed upon bodies of a smooth superficies , such as glass , cristal , ivory , and polish'd metals , or gems , it still continues asleep , and shews no sign of life ; so that it needs some small inequality and asperity of the superficies ; as cloath , linen , and a thousand other things have , unnecessary to be named here : and likewise human flesh excites this power ; but some more , some less : and we have known some , that let it be rubbed never so long on their hand , yet could not happen to make it attract . it is commonly believed , that amber attracts the little bodies to it self ; but the action is indeed mutual , not more properly belonging to the amber , than to the bodies moved , by which also it self is attracted ; or rather , it applies it self to them : of this we made the experiment ; and found , that the amber being hung at liberty by a thread in the air , or counterpois'd upon a point like a magnetical needle ; when it was rubb'd and heated , made a stoop to those little bodies , which likewise proportionally presented themselves thereto , and readily obey'd its call . liquors also are sensible of this power of the amber ; the smallest drops of which , it attracts , even those of mercury : indeed it is unable to manage them , except very minute ; whence it soon lets them go , after they have been attracted : but when we have presented it to the superficies of standing liquors , and mercury it self , it did not raise up one drop ; but as it were , made the level of the superficies swell under it ; which raised it self in a little bubble toward it , but inverted so , as to respect it with its pointed part . this effect may be better observed in oyl , or balsam ; than other fluids there are some liquors wherewith the amber being wetted , after rubbing , draws not ; and there are others not producing this effect ; they that so act , are generally all natural waters , distilled waters , wines , vinegar , burning waters , all acids ; the juces of all sharp fruits , all liquors distill'd from animals . balsames , and all artificial liquors , as juleps , essences , spirits , and oyls made by distillation : on the other hand , these are ineffectual ; oyl of flints , sallet oyl , oyl of sweet almonds , and bitter , made by expression . tallow , fat ; and lastly , all butter , whether simple , or perfumed , with any flowers , ambergrice , or muske ; provided unmix'd with essences or oyles . a particular effect has been observed in diamonds , whereof the roses ( as we said ) are reckon'd among the most electrick gems ; but the tables were found so weak , that they seemed sometimes quite deprived of that virtue ; and some thought that their plain superficies had no part in the effect , seeing when the diamond has depth , tho smooth'd and polish'd upon the wheel , it draws vigorously ; whereas the flat table-stones , that are shallow , such as are set in lockets at the end of neck-laces , commonly called spere , tho very large , when strongly rubb'd , will yet not draw ; or if they do , 't is so faintly , that you must make them touch some hairs of the bit of paper , or straw , to make them raise it up ; yet 't is not to be doubted , but some may be found that have a little force ; yet of these , we at least were so unsuccessful as to find but few . we indeed had one which by many trials for several days , we were never able to make attract ; but a year after , desirous to see the same tryed again , we took the same ring in which the stone was set , and having but slightly rubb'd it , as we used to do upon the cloath , as soon as ever it was held to the bit of paper , it drew it vigorously : this same effect was often observed with wonder by all those that the year before had often attempted in vain to make it draw : and on the contrary , ( as we said at first ) the fausets ( i. e. ) those that are ground of their own octoedral figure , seldom or never failed . in fine , since amber , and all electrick bodies have been observed to be obstructed by a very thin vail placed between them , and the thing to be attracted ; therefore taking a sheet of paper , we made several little lattices in it ; and the first of them was covered with a close network of hair , another with the lint of a fine rag , a third with a leaf of gold ; the success was , that the electick power of the amber did not penetrate them . experiments about altering the colovrs of several flvids . there is nothing more frequent amongst the niceties of the chymists , than their fantastic humour of changing colours ; we indeed do not professedly meddle therewith ; and if any such tryals were made , we were moved thereto , from the occasion we had of making use of some liquors , fit to examine the qualities of natural springs . concerning which , we will relate the little that came to our knowledge ; again reminding the reader , that by the perfixt name of essays , we would intimate , that we do not presume , we have examined these matters with all the experiments which may be thought on ; but onely barely given some hints of those things we were most inclined to take pains about . the first experiment , of altering water . water distill'd in a leaden still , thickens and muddies the water of all rivers , baths , fountains , or wells wherewith it is at any time mix'd ; and losing their transparency , they both look white like whey ; onely water distilled in glass vessels , and of spring water , that of the conduit of pisa remains limpid and transparent . but all those waters so muddyed , become clear and pure again by a few drops of strong vinegar shook together with them . the same waters are changed by a dropping in of oyl of tartar , and oyl of anniseeds , which give the appearance of a little white cloud higher , or lower , therein ; which by shaking , diffuses it self through all the liquor , and inturbidats it . this also is brought to its former clearness , by a small quantity of spirit of sulphur , which at first raises a few little bubbles . note , that all waters indifferently do not become turbid by the above-named oyls ; and those waters that are not altered by waters still●d in lead , are likewise left transparent by oyl of tartar and aniseeds . moreover , inflammable waters , waters still'd in glasses , and that of the conduit of pisa , are not at all changed from their natural clearness ; and we find that in waters generally held the lightest , purest , and noblest , the little cloud is thinner and higher , which is raised therein ; and onely in heavy waters , and those that are impregnated with minerals , or dreggy , it thickens it like milk ; whence some have pretended to prove waters with some of the above-named liquors ; for thereby is discovered the more hidden quality of them , and so their goodness or badness found . if at any time the thickness , and turbidness of the water is very great , and not to be clarifyed by the ordinary proportion of liquors , it may be increased by some drops still agitating the water , till you see it become clear . the second experiment . of altering wine . oyl of tartar , not onely in water , but also in wine , produces the same effect ; for through its natural cleansing quality ( as is known ) it makes a separation in all liquors , of what ever is mix'd with them , from the purer parts , by a sediment that it lets fall ; whence that which shews like a white cloud , higher , or lower in the water , according to its different qualities and weight , in all sorts of white wines that we experimented , appears like a thin cloud of a red colour , which by shaking the wine , quits its first place , and disperses it self uniformly throughout the whole body ; it makes no other change in red wines than a little tinging deeper ; especially toward the bottom . on the contrary , spirit of sulphur shews no alteration in the natural transparency of the wine ; and likewise restores it to those deprived thereof , by the oyl of tartar. the third experiment . of the tincture of roses . a tincture of red roses ( extracted with spirit of vitriol ) being mix'd with oyl of tartar , shews a fair green : with a few drops of spirit of sulphur , it ferments all into a vermillion froth , and at last returns to its first rose colour , without losing its smell at all ; nor will it be again altered by dropping oyl of tartar into it . we found the best way of getting the tincture of roses for this experiment , as follows . taking a good handful of dryed red rose-buds , we cut them , and putting them in a glass , with one ounce of strong spirit of vitriol , stirred them together for a quarter of an hour , in which time the roses were well macerated , and the tincture extracted ; to this must be added , at three or four times , about half a pound of spring water , still shaking the glass till the very deep colour of the spirit being diluted , the water is all tinged therewith : then we let it stand an hour , and so obtain a lively and beautiful tincture of roses . to half an ounce of this , put ten or twelve drops of oyl of tartar , and afterward as much spirit of sulphur , which suffice to produce the related effects . the fourth experiment , of the tincture of saffron . water tinged with saffron , helped a little with the tincture of roses , but not so as to lose its golden colour , changes green with oyl of tartar , and again yellow with spirit of sulphur . the fifth experiment . of greens . water coloured with iris green , mix'd with spirit of sulphur , makes a purplish colour , and with oyl of tartar takes its own again . this green is a tincture taken from the purple flower-de-luce , which prepared with a mixture of quick-lime , gives a pleasant lively green , much demanded by limners ; then 't is set to evaporate and dry in muscle-shells , as shell - gold and silver . see more fully the ways of making the like extracts in neri's book of the art of glass-painting , printed at florence , , lib. . cap. , , and . as likewise , how to take the lake of any flower . the sixth experiment . of violet colours . juice of limons , spirit of vitriol , and spirit of sulphur , change the violet colour of lacca to heighten gold , and the tincture of blew violets , into a vermillion ; which with the oyl of tartar again , makes a purple : also vinegar gives them a red colour , but 't is fainter . experiments about the motions of sounds . sound , that noble accident of the air , keeps so unchangeable a tenour in its motions , that a greater or lesser impetus wherewith the sonorous body produces it , is unable to alter it . this strange propriety of sounds is related by gassendus , who affirms positively , that all sounds , whether great or small , pass the same space in the same time : and he declares , that he had experimented it in two sounds , the one much louder than the other ; that is , one of a musket , and the other of a piece of ordnance : in repeating this experiment , which we found undoubtedly true , we happen'd to observe some particulars which we did not think fit to conceal , since possibly they may offer something not thought upon by every one ; or if thought on , yet all persons may not have the opportunity and means of satisfying themselves experimentally . the first experiment , of sounds passing equal spaces in equal times . we made this experiment in the night , with three several sorts of pieces , with a harquebuss , a falconet , and a demicannon , planted at three miles distance from the place of observation , whence we could well discern the flash of the powder in firing the pieces ; from this flash then , we always counted an equal number of vibrations of the pendulum of a clock , whether the shot was of the harquebuss , or the falconet , or the demicannon , and that upon all levels and directions of the barrels of those pieces . since gassendus was so taken with that known example brought by the stoicks to represent to the life how the invisible propagation of sounds is made by the air , we will take this opportunity to consider it : they say , that , as we see standing water move in circles by casting in a little stone , which waves successively enlarge into greater and greater rings , till at last they reach the bank of the water , and there vanish ; or dashing themselves against it , are reflected back again : so they assert , that the air every way undulates from the sonorous body in successive circles for an immense space , which wavings meeting with our organs of hearing , and finding them soft and yielding , impress upon them a certain tremour , which we call sound : hitherto the stoicks , without prosecuting it any farther : but gassendus was so pleased with the aptness of the example , that he desired to go through with it , and make it capable of explicating the peculiar properties of sound ; one of which , as was said , is the unalterable velocity of its motion : whereupon he says , that the undisturbed proportion of the swiftness of sounds , agrees with a like observable also in the undulations of water , which he affirms , are neither swifter nor slower , but always with the same degree of velocity approach the shore , whether made at first by a great or small stone , whether falling onely with its own weight , or forceably cast thereinto : which nevertheless ( with due respect to so great a man ) we have not found to answer ; for we have observed by frequent experiments , that by how much the stone is larger , and the force greater , wherewith 't is thrown into the water , by so much the circles approach the shore swifter . the second experiment , of contrary , and favouring winds . there is another strange observable in the motion of sounds , related also by gassendus : ( i. e. ) that it is neither retarded by a contrary blast of wind , nor accelerated by a favouring gale ; but always travels the same space , with an uninterrupted course , in the same time . this likewise we desired to bring to the test , and found it true , thus : at a season when the west wind blew , we made two discharges of two pieces , one planted westward , the other eastward , at an equal distance from the place of observation : so that the one was favoured by the wind , the other crossed ; but for all this , they both transmitted their sound to the observer in the same space of time , measured by the equal number of vibrations of the same clock : though indeed , that which was eastward , and so against the wind , was observed much more languid , than that which was westward . the third experiment , of the equability of motion in sounds . one of our academy took occasion from those experiments to think , that the motion of all sounds might be equable , as well as equally swift ; we arguing , that thence , if true , many curious and profitable hints might be gained : but first , to be fully satisfy'd if there were really any such equability , we made the following experiments . at the distance of one of our miles exactly measured , which are about of our braccia , or foot , we fired several pieces , that is six harquebusses , and as many chambers ; at each whereof from the flash to the arrival of the report , we counted ten whole vibrations of the pendulum , each for which was half a second . repeating the experiment at half a miles distance , that is , at the mid way , we observed it to be exactly in half the time , always counting at each report , about five vibrations , wherefore we rested satisfyed of the certainly of this equability . the consequences which we pretend will follow from this equability , amongst the rest are , that by the flash and sound of divers shot , we might obtain an exact measure of the distances of places ; particularly at sea , of ships , rocks , and isles , where we cannot come to take several bearings , as is requisite in using the common instruments : we may also by a single stroak made upon wood , stone , or metal , or any other sounding body ; judge how far off he is that gives the blow ; telling the vibrations between the stroak seen , and the hearing of the noise , which if the wind be favourable , may be heard for some miles , and it will be easie as well as curious , to find the distance of clouds from us , and of what height from the earth , thunder is generated , counting the vibrations between the lightning and the blow . if we would likewise know the distance of places , which because of the roundness of the earth , or interposition of hills , we cannot have a sight of , yet with ease we may obtain it , and that by two discharges , answering each other ; so that to our firing at one place , they must return another at the other place ; and taking the middle time between our discharge , and the arrival of their answer , the half of the sounds journey will be found , that is , the whole distance of the places sought . by the same way of sounds , the maps of particular places may be adjusted , and truly laid down in plano ; taking first the angles of position of the cities , castles , and villages , to place them in their due scituation ; with several the like curious inventions very , useful , nor to be disesteemed . then to gain the unknown distances of each , we may make use of time for a scale , the sound travelling with us the known space of a mile in five seconds . experiments about bodies projected . it was galileo's opinion , that if a culverin be planted upon the top of a tower , and a shot be made point-blank ( i. e. ) horizontal , according as the charge of powder in the piece is greater or less , so should the ball fall at a proportionate distance of , or , or , or braces , &c. and that all these shot would be made in equal time to each other , and all equal to the time of the balls falling from the mouth of the piece to the ground , without any impulse ; but onely dropt perpendicular , when there is no accidental hindrance from the air , which may in part impede the swift motion of the shot : we were desirous to bring this to the test of experience , and it seemed to us , that we succeeded very well ; wherefore we will relate what little remarkables we can with certainty say that we observed on this subject . the first experiment , of horizontal shot , with a falconet from the top of a tower. upon the top of the tower of the old fortress at legorn , about foot high , with a falconet carrying an iron ball of l. ⅓ with a charge of l. fine powder , we made several shot horizontal into the sea with the balls , and observed them to fall into the water at about ⅔ of a miles distance in ½ vibrations , each whereof was an half second : and examining the perpendicular fall of other balls of the same size from that height of braces , we found there were of the same vibrations . the second experiment , with a demi-culvering . with a demiculvering carrying l. ball of iron , and l. of fine powder , the balls being wrapt about in of the above-mentioned vibrations , fell into the water ; and without being wrapt about in ½ vibrations ; whence it seems , that they flew farther than the other . the third experiment , of perpendicular shot with an harquebuss . galileo writes in his discourse of bodies projected , words to this purpose : from the height of , or more braces , fire an harquebuss with a leaden bullet perpendicular to a stone pavement , and with the same charge shoot another at the distance of one or two braces upon the like pavement ; examine then which of the two balls shall happen to be more battered ; for if that from above shall be less battered than the other , 't is a sign that the air has retarded it , or diminish'd the velocity imparted thereto by the fire at the beginning of its motion ; and consequently , that the air will not permit such a velocity to increase by falling from any great height . that when the velocity communicated by the fire to the ball , excceds not that which the same ball would naturally acquire by descending , the stroak of the ball downward then ought to be rather more violent than faint . i have never made the experiment ( galileo subjoyns ) but am inclinable to think , that the ball from an harquebuss , or piece of ordnance coming from any great height perpendicular , will not give such a blow , as it will when discharged upon a wall some few braces off ( i. e. ) so few , as that short passage , or ( we would say ) cutting of the air , shall not have taken away the excess of the unnatural violence communicated by the fire . we made this trial with a harquebuss , not firing it against a stone pavement to observe the battering of the bullet , but against an iron breast-plate , and in this we found that the shot from a lesser height made a deeper impression than that from a greater ; because as was urged by some ( after galileo ) in a longer passage the ball loses continually ( by cutting the interposed air ) some of the impetus , and preternatural force received from the violence of the fire . the fourth experiment . that the power of motion already imprest , is not destroyed by a new direction . in confirmation of what galileo affirms in several places , viz. that the virtue imprest upon bodies projected , is not destroyed by a new direction of motion , it was by some proposed to make the following experiment . we fitted upon a carriage with six horses , a saltamartino , carrying l. ball of iron ) so as it stood perpendicular to the horizon ; with this we made divers shot with the same quantity of three penny weight of musket powder ; some we made with the carriage standing still , others while it ran a full cariere upon a level plain : at the first trials the ball fell near the mouth of the piece : at the second , after the carriage had run paces from the firing , to the return of the ball , it came short of the piece but about ½ foot , where it fell ; all the times were very near equal in all the trials . the fifth experiment much to the same purpose . we made the like experiment with one of those crosbows that are bent with a bender , its bullet of lead weighing three ounces , and in foot course ( we mean from the discharge to the return of the ball ) it came short of falling upon the carriage but ½ foot , and a ball of common clay in running foot , fell short three foot. whence some confirmed themselves more in the opinion of the same galileo , that the air takes not a little from the force of heavy bodies , that cut it , but more sensibly of light bodies . miscellaneous experiments . though it has been always chiefly endeavoured in our academy to keep a continued thread of experiments upon what subject soever they were made ; yet that did not hinder the admission of any particular observations as they were still suggested by any of our members , arising from their proper studies , tho from the design then chiefly intended : now of these irregular experiments , there being some quantity , since they have little or no connection together ; altho they may be instructive , we have reserved some essays of them , like the former , for the last place , as a conclusion of the work. an experiment , to know the absolute weight of air in respect of water . there was taken a ball of lead , closed every way , and full of air ; because this being immersed in water , swam thereon , we charged it on the outside with so much lead as sunk it ; and weighing all in exact scales , we found it gr . being plunged in water , the same altogether weighed but gr . so the difference was gr . which was the absolute weight of a bulk of water equal to that of the whole ball , and lead . then pressing the ball together , as much as its thickness would bear , without letting the air out , and weighing it in the air with all the lead , 't was found ; and this we concluded was the absolute weight in uncompress'd air , as that was , which was in the ball before it was battered together . in this state all being put into the water again , and weighed , 't was found gr . , which substracted from gr . , ( the weight of the ball prest together in the air ) there remained gr . , the weight of a bulk of water , equal to the bulk , of the same lead , and battered ball. this weight then of gr . , being substracted from the other of gr . , left gr . which was the weight of a bulk of water equal to such another bulk of air as weighs gr . ( which bulk was equal to the diminution of the bulk of ball by the battering : ) whence we concluded , that the weight of that sort of air which we weighed , is to the weight of so much water , as , to ; that is , as , to . this experiment being by us repeated at divers times , the proportion was not always found the same . indeed , the variations have not been great , consisting in one , two , or three hundreds of grains , more or less : which is all we can pretend in making the comparison between one body that , as we may say , never alters in its weight ; and another , never twice the same . experiments touching some effects of heat and cold. the first experiment . of a steel wire , seeming to grow lighter by being heated . putting in the essay-scales two steel wires of equal weight , the one heated , the other cold ; it seemed that this was heavier than the other : but holding a lighted coal , or red-hot iron near it , it soon came to an aequilibrium with the hot one . the same would have happened if they had been of gold , or silver , or any other metal : likewise , if a lighted coal be held over one of the basons of a pair of scales , when empty , it raises it ; and if held under it , it causes it to descend . for all this , some of us could not apprehend , how the bare heating could any ways alter the usual weight of the metal ; nay , 't was thought by some , that the pressure of the air might have its part as well as any other cause , in producing this phenomenon . the second experiment . of the vast force of heat in raising up an included liquor . having filled with sp. vin . half of the vessel ab , whose slender part was / inches long , with two sealed balls of equal capacity , we set the ball a in a glass of oil , over the fire , and the sp. vin . began to give notice of its rarifaction by rising : but afterwards , when the oyl boil'd very fast , it retired all into the upper ball , leaving that below quite empty with the lower half of the cane . it is also necessary to promote this effect , besides a strong fire , to blow the coals continually about the glass ; ( this must be done through the hole of a plank , serving to defend the operator ; behind which also the observer must stand to look thorow a glass in the same plank ) for when the sp. vin . is all forced into the upper ball , 't will be thrown off : and not onely that , but the lower will be burst with such force , as one time amongst the rest , making use of a brass vessel , instead of the glass , for the oyl , it broke the bottom thereof , and tore off a band of iron of the thickness of a crown , and crack'd a stone in the pavement . but we made choice of oyl , and of glass vessels ; because their transparency makes the procedure of this admirable effect more visible . else wax , pitch , or lard , or it may be any unctuous matter may produce the same effect . the third experiment , about antiperistasis . to do something upon the score of antiperistasis , we filled with ice finely powdered , a leaden vessel , and putting thereinto a thermometer of deg . we let it stand still , and it composed it self to about ½ deg . then we plunged the vessel into a cauldron of boyling water , regarding nicely the thermometer , if in that instant that the ice became encompass'd with its contrary , it then gave any shew of greater cold , by subsiding . but that , as often as we repeated the experiment , was never seen to alter a hair : nor was it ever observed to rise , when the vessel being full of hot water , we plunged it in water mix'd with ice : nay , then it was readily seen to subside ; for as much as the fluid water more easily gave a passage to the quality of the ambient , than in the first experiment the ice could do . nor let it be thought that all the care possible was not taken to prevent the air encompassing the thermometer from receiving any alteration , upon immersing the leaden vessel in different ambients , the said vessel being let into a plank , which was very broad round it , and so cut off all communication between the bason under it , whereinto the bottom was immersed , and the air above ; but for all this , we observed no difference from what is related . the fourth experiment , whether cold be caused by an intrusion of frigorific atoms . to gain some light , whether the chilling of bodies were caused by the insinuation of any kind of peculiar atoms of cold , as the opinion is , they are heated by those of fire ; we caused to be made two glass vials like each other , with very slender necks : being sealed hermetically , we put one of them in ice , and the other in hot water ; letting them remain some time , and then breaking the neck of each , off under water ; we observed in the hot one a surcharge , or repletion from something got into it , observable by the bubbleing of the water , from a strong breath issuing from the vial as soon as ever it was broke open . some might think the same should have happened in opening the cold one , if the chilling of the air therein had proceeded after the same manner , as the heating of that in the other ; ( i. e. ) by the intrusion or soaking of the atoms of cold exhaled from the ice , through the invisible pores of the glass : but the quite contrary happened ; for instead of breathing forth any surcharge of matter , it shewed an emptyness , or loss of something , ( if there was not a condensation of what was there ) since it suck'd in so much water in place of it . the fifth experiment . of heating and cooling of water by salts , &c. and of hot and cold ebullitions , &c. vitriol , the spirit being drawn off , remains like a tartar , or grumous body , of a lively fire colour , which with a long and continued fire distills a blackish oyl , almost like inke , highly corrosive . this being mixt with water in a certain proportion , produces an immediate heat , which increases without raising any bubbles , or perceivable smoak , till the glass wherein this mixture is contained can carce be endured in the hand : the like happens by mixing it with all other liquids , except oyl , and strong waters ; of which , the first is not in the least altered from its natural state : and the second , if a tall , scarce sensibly . on the contrary , 't is a known experiment , that nitre dissolved in water , chills it : and sal armoniac congeals to that degree , that if in the water wherewith 't is mingled in a due proportion , you set a thin glass of other water ( cooled , before well with ice ) the cold produced by the said salt , as it dissolves , will freeze it . having mingled together one third part of sal armoniac and two thirds of the forementioned oyl of vitriol , there followed an unusual effect : for still as the salt dissolved therein , it smoaked , and boyled up furiously , and so much the more if we stirred it together with a little stick , for then it rose up much easierly in froth , so as it then filled a space times bigger than the bulk of the two separate bodies , of oyl and salt : but for all this fury of smoak and boyling , we not onely could observe no sensible beginnings of heat , but a strange degree of cold produced therein , chilling the glass that contained it ; and the spirit of wine , of a thermometer immersed thereinto swiftly subsided , till the salt being dissipated , and evaporated , the boyling ceased , and the oyl returned to its former natural state . such a production of cold we have known , when ever we have repeated the experiment ; indeed that , as well as the ebullition and smoaking , is more or less , as the salt is stronger , or the liquor more refined . we have also observed , that a few drops of strong water , or sp. of vitriol put into the oyl in its greatest fury of ebullition , stops it , and makes the mixture immediately hot ; adding oyl of tartar , the heat is augmented ; the smoke , and ebullition returning ; but by dropping in of sp. of sulphur it quickly cools again . it is worth a little reflection : that as oyl of vitriol mixt with all liquors , heats them , ( oyl and strong water excepted ) so contrarily sal armoniac stirr'd together with all liquors , cools , and refrigerates them more or less ; ( oyl , and strong-water likewise excepted , upon which two only 't is ineffectual : ) and again , that upon mixing together ▪ the same oyl of vitriol , and sal armoniac , there should follow so wonderful a cold ebullition as is related . some experiments , to know if glass and crystal be penetrable by odovrs and hvmidity . the first experiment , touching odours . oyl of wax , quintessence of sulphur , and extract of horses vrine , which are reckon'd the most acute , and strong smells that are ; do not sensibly transpire through a sealed glass vial , as could by many persons that tryed it , be perceived , tho 't was heated . the halitus also of that thin spirit that flies away upon cutting an orange , or lemon peel , or which in a small thread spins out of the same peel when it is squeezed , did not penetrate to give any smell to a little water contained in a cristal glass sealed hermetically . in like manner , sealing up a partridge in a small glass vessel , and setting it in a corner of the room , and bringing a setting dog in , we led him round , near the place where it was set ; but he shewed no sign of perceiving the partridge . the second experiment , of humidity . a glass ball being filled with salt , well ground to powder , and dryed , was sealed up at the flame of a lamp , and put for ten days at the bottom of a cistern of water ; and after that , as long in a conservatory of snow ; but it did not increase at all in weight ; and when broken , the salt was taken out so dry , that it fell to powder . yet we have sometimes chanced to find in the ball of salt some little part thereof dampish ; but we can not argue a penetration from thence ; for if it were really so , it ought not to be more in one place than another ; whereas , that little moisture being always found in one place , 't is very probable it was onely a little of the humidity which the force of the cold drove out of the air remaining in the ball , and sticking as a cover to the inside thereof ▪ some experiments concerning light , and its effects . the first experiment , of the instantaneous motion of light. galileo in the first dialogue of his treatise of two new sciences ; suggests an easie way to discover , whether light moves in time , or with an instantaneaus velocity : the trial consists in the confederacy of two companies of men to expose two lights to each others view , so that the discovery of the one , may answer immediately to that of the other : that when the one uncover their light , and expose it , they may at the same time perceive the light of their confederates . this being often practised at a small distance galileo desired to have the same tryed by observers at a greater distance ; to see , if the mutual correspondence of exposing and covering their lights , kept the same measure as when nearer ; that is , without any observable delay . we tryed it at a miles distance ( which in the going forward , and return of the light must be reckon'd two , and could not observe any . if in a greater distance it be possible to perceive any sensible delay , we have not yet had an opportunity to try . the second experiment , of fi●ing bodies with a burning-glass . the light refracted by a crystal lens , or reflected by a burning concave , will not fire spirit of wine , tho made opaque by a tincture . amongst other combustible matters , gunpowder fires upon the uniting the rays of a lens or concave . but the perfumed pastils , white balsame , storax , and incerse , melt , but will never take fire . likewise paper , and fine white holland , when exposed flat to the reverberatory of a large concave , at length fire : wherefore 't is a mistake , that the light will not inflame any white bodies , as is generally thought ; indeed they take fire with more difficulty , than coloured bodies , and it may be with a small concave or lens they will not fire . the third experiment . of bodies affording light. besides fire-stones , there are other bodies that seem to be greater conservatories of light ; for by striking them together , or by breaking them in the dark , they sparkle . such are white-sugar , loaf-sugar , and sal-gemme in the stone ; all which being broken in a mortar , give forth so great a light , as distinctly to discern the sides of the mortar , and the shape of the pestle thereby : but we have not succeeded to see the same appearance in pounding common stone-salt , alumn , or nitre ; nor in coral , the yellow or black amber , gr●●ats , or marchasites : but rock-chrystal , and agate , and oriental jasper , either struck together , or broken , give a clear light. experiments about the digestion of some animals . wonderful is the force wherewith the digestion of the hen , and duck-kind is performed ; for they being crammed with little balls of solid crystal , were dissected by us in a few hours , and opening their ventricles in the sun , they seemed to us covered all over with a glittering coat , which examining with a microscope , we found it to be onely strewed over with exquisitely fine and impalpable powder of crystal . in others , likewise crammed with hollow bubbles of crystal-glass with a small hole in them , we were amazed to find of the said bubbles some already broken , and powdered ; others onely crack'd , and filled with a whitish substance , like curdled milk , got in at the small hole ; and we also observed , that those were better powdered , ( than the others ) which had in the maws with them a greater quantity of small stones . and 't is less strange , that they break , and grind to pieces , corke , and any hard woods , as cypress , and beech , and rub to powder olive-stones , the hardest pine-apple kernels , and pistaches put down their mouths , with the husk on . pistol bullets in twenty four hours we have found much battered ; and several little hollow square boxes of tin were observed to be some scratched , and battered , others tore open from one side to the other . finis . a table of the principal matters contained in this work. a. academie del cimento intends not to dispute of the experiments . page . , and . air diminishes the force of all bodies that cut it . p. . perhaps in continual motion . p . presses together those bladders that seemed full in vacuo . p. . dilates and expands it self in vacuo . ib. what remains in the void space above ▪ the mercury presses not thereon . p. . when it is dilated beyond the state of its natural compressure , p. . the measure thereof , ib. proportion between air natural , and air expanded , as to . p when most rarifyed , unfit for respiration of animals , p. . of altering the colours of several fluids . p. . amber in vacuo loses its electric quality , p. . which sort richest in that quality , p . attracts any thing but fl●me , p. . rubb'd upon smooth bodies attracts not , p. ▪ acts no more upon the attracted body than it suffers thereby , p. . acts upon all liquids . ib. by what liquors hindred from attracting , p. . antiperistasis , experiments against it , p. . attraction by what hindred in amber , by the same also in other bodies of electic virtue , p. . a peculiar effect observed in the attraction of rose and table diamonds p. ● b. balls of glass burst with great violence , p. a barbel taken alive out of a vacuum , and kept in a pond , with some observables thereon , p. birds soon killed in vacuo , and why , p. bladders of fish in vacuo , p. bl●bs in ice what , p. brass , to what thickness , burst by frost . p. bullets not wrapt about , fly farther with the same charge of powder than those that are p. c. canes of glass how made to be stop'd with a finger easily , p. cement to joyn together the mouths of vessels . p. change of air produces an alteration in experiments , p. changing of colours in several liquors , p. circles in water move swifter , as the force that makes them is greater , p. clocks uncapable to shew the minute divisions of time , p. . why made use of in the experiments of freezing , p. cold whether reflected by glasses as heat and light are , p. cold and heat , clouds and mists encrease and lessen the weight of the air , p. . supposed by some the parent of rock cristal , and gems , p. . whether any thing positive , or onely a privation of heat , p. . once imprest upon a fluid shoots it into ice after 't is taken out of the freezing mixture , p. . * whether caused by an intrusion of frigorifique atoms , p. : d. dew upon the outsides of glasses frozen , p. diamonds how generated according to plato . p. table diamonds less electric than roses p. digestion of some animals how performed , several experiments thereon . p. drops of liquors thought to be spherical from the airs pressure , p. disproved p. e. a cold ebullition , caused by a mixture of sal armoniac , and oyl of vitriol p. a strange effect of heat in subliming liquors , included in vessels p. electricity , what substances impregnated therewith p. experiments requiring an exact measure of time p. the best way of examining nature p. ● extrusion , or pulsion of bodies , a thing known to the ancients , more especially evident from a passage in plato's timeus , p. f. fire and its effluvia what effect they have in vacuo . p. fishes kept a while in vacuo dye , disgorging some air. p. flame diverts , and abates the virtue of amber , p. fluids aptest to move , and why ? p. why different fluids are raised to different heights by the incumbent air p. . fluids added to the airs pressure , raise the mercury above the usu● height p. force of rarifaction in freezing water , how great p. how thought reducible to dead weight ib. freezing , how caused in fluids , p. artificial , with its procedure and accidents , p. * made in a very short time , almost instantaneous , p. * what order it observes in divers fluids p. tables of freezings p. ib. the expl●catian of the terms used in the tables of freezings , p. those of the same fluids repeated , still uniform p. natural freezing , with the procedure thereof p. diversity of the figure of the vessels causes some little diversity in the freezings , p. whether caused by the intrusion of frigorifick atoms p. froth in vacuo expands it self p. a sort of funnel to fill vessels with narrow necks p. g. gems transparent , all electric more or less , p. glass vessels enlarged by hot water , and lessened by cold , p. stretch'd by the weight of the contained mercury , p. impenetrable by odours , and moisture , p. glass balls burst with great violence , p. glass and cristal electrical , p. gold vessels distended by the force of freezing , p. gun-powder fired with a burning glass , p. h. height of liquors set in hot water , or ice altered by the dilating or contracting of the vessel p. horizontal discharge of cannon dispatch the ball in about the same time that it falls from the mouth of the piece perpendicular to the ground , p. humidity of winds how distinguish'd , p. i. ice according to galileo is water rarifyed , not condensed , p. has not its full hardness at first , p. produced by art tenderer than the natural ib. made in vacuo , wherein different from that made in air p. how to find that difference ib. sends forth a moist exhalation p. sprinkled with salt destroys the vertue of amber p. the cause thereof proposed by some p. instruments shewing the heat and cold of the air p. shewing the moisture of the air p. to measure time p. shewing the different pressure of the air p. shewing the alteration of the natural compression of the air p. . an instrument convenient to make the vacuum p. made use of in artificial freezings p. * iris-green what ; p. l. light : bodies most impregnated therewith p. whether its motion instantaneous p. transcurs the space of miles in an undiscernable time p. the supposed positive lightness of bodies does not raise them up p. experiments thereon liquors making other fluids turbid and clear again p. m. magnet not hindred by the interposition of any fluid , or solid body p. its north pole weaker when placed southwards than northwards p. mercury fittest to make the vacuum p. at what height sustained in vacuo p. altered by external accidents ib. raised higher in an ambient of water than air ib. a vial filled with mercury not running out p. how high raised in a tube by the simple pressure of water , p. rises or falls as the place of observation is higher or lower , p. dissolves snow put into it p. is attracted by amber p. metal of the vessel causes no alteration in the liquors freezing p. which sort preserves ice best p. dilated by the heat of fire p. moisture of the air shewn by instruments p. motion observed in the heights of liquors , when first the containing vessels are set in several ambients p. muscadine , its effect in freezing p. n. nitre chills water when mix'd therewith p. , o. oyl of vitriol mix'd with water produces a great heat p. and with all fluids the like except oyl , and spirit of wine ib. that , and sal armoniac together , make a cold ebullition ib. &c. p. paper white fired with a burning-glass p. pearl with what effect dissolved in vacuo p. pendulum's the best time-meeters p. their description and use p. their vibrations quicker or slower according to their length p. first applyed to clocks by galileo ib. plato's thoughts of the raising up of fire and water by the air p. poles of the magnet when most efficacious p. prejudices against material instruments p. pressures of the air acts upon all fluids p. its difference shewn by instruments p. experiments in favour of that pressure p. objections against it p. the reply of some persons thereto p. procedure observed by some liquors in freezing * proportion of air natural , to that rarifyed , not still the same p. whence it may proceed ib. r. raising of fluids higher in small canes not onely to be attributed to a weaker pressure of the air in them p. the reflection of the object by the lens the same in vacuo as in the open air p. reports of a demicannon &c. pass equal spaces in equal times p. rings turned out of wood , by imbibing moisture dilated p. cilindrical rings of brass dilated , by heating in the fire p. the same vigorously frozen , contracted p. rods of steel seem lighter hot than cold p. s. sal armoniac , most efficacious in producing cold p. mixt with water arrives to a degree of freezing p. scale for the velocity of sounds p. scope of the academy in their experiments with mercury p. smoak descends in vacuo in a parabola p. snow melted by mercury p. dissolves as slowly in vacuo , as the open air ib. snow-water longer in freezing than other liquors p. yet the same after boiling ib. sounds pass equal spaces in equal times p. how propagated , according to the stoicks p. vnalterable in their velocity p. sound of a bell and organ the same in vacuo , as in the air p. spirit of wine makes no sediment p. sprinkled upon ice increases the cold p. not to be enflamed with a burning-glass p. that , and spirit of vitriol ferment with water , with ebullition , and heat . p. spirit of sulphur stops fermentation , and chills p. a cold steam from vessels filled with ice p. sugar promotes freezing p. superficies of ice , how raised in the midst p. t. tables of freezing p. thermometer what , p. how sealed p. vsed in experiments of freezing , and why , p. their exactness unalterable by the small alteration of the capacity of their head or ball p. tincture of roses how made p. tinctures altered to several colours by an infusion of divers spirits ib. v. vacuum what intended thereby p. made better with mercury than by succion p. velocity communicated by the powder to the bullet , when fired downwards preternatural thereto , according to galileo's sentiment p. confirmed by experiment vessels with small necks how filled p. one made use of in many of the experiments of vacuity p. of several materials burst by frost p. of earth contribute most to the freezing of the contained liquor p. of metal , and glass alter their capacity by the external application of heat and cold p. the temperament of the contained liquor yet unaltered p. vibrations of the same pendulum not always equal p. vincenzio galilei first adapted the pendulum to clock-work p. vinegar stil'd , dissolves pearl and coral p. virtue electric in what substances most conspicuous p. hindered by the least obstacle interposed p. virtue , or force already imprest upon bodies not alterable by a new direction of motion p. w. water , in vacuo rises not above foot inches p. how tryed with other liquors p. with what care it ought to be set to freeze in vessels p. after remounting upon freezing continues to rarify p. in specific gravity to ice , as to ; or as ½ to p. in freezing , forces through the screws of vessels p. frozen in vacuo p. difficult if at all to be comprest p. attempted by rarifaction of air p. dead weight p. percussion p. still'd in lead thickens fair water p. a way to open , and close again quickly , and easily any glass vessel p. weight able to enlarge the capacity of vessels p. specific weight of air in respect of water how found p. winds contrary or favouring neither retard , nor accelerate the motion of sounds p. the contrary onely weakning the vivacity thereof ib. notes, typically marginal, from the original text notes for div a -e provando . e riprovand● . notes for div a -e tab. . fig. . smalto bianco . smalto nero. tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . libecciata aquilonari libecci ▪ poneuti . bra. ● / tab. . fig. . . brac. brac. brac. ¼ brac. ¼ tab. . fig. . tab. . fig. . tab. . fig. . brac. ¼ tab. . fig. . brac. tab. . fig. . fig. . fig. . tab. . fig. . brac. ¼ tab. . fig. . brac. tab. . fig. . br. ¼ tab. . fig. . brac. ¼ tab. . fig. . brac. ¼ tab. . fig. . brac. ¼ brac. ¼ tab. . fig. . braccio br ▪ . br. . notes for div a -e tab. . fig. . smalto . tab. . fig. . ½ brac. tab. . fig. . ⅓ di brac. ⅔ di br. tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . astr . opt. tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . brac. tab. . fig. . pastiglia nera . ⅓ di brac. brac. lucertole . mignatte fig. . tab. . fig. . tab. . fig. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . brac. ½ di br. brac. ¼ notes for div a -e mignatta lumaca . grilli . farfalla . moscone . lucertola uccelletto . calderugio . allodola . passera . brac. ¼ granchio . tenero . ranocchio . granchio duro . ranocchio . pescett● . barbio . anguilla . barbio . brac. ½ tab. . fig. . tab. . fig. . lasca . tab. . fig. . lasca . ● br. / notes for div a -e job . ver . . tab. . fig. . tab. . fig. . piastra tab. . fig. . & . fig. . fig. . ottone piastre tab. . fig. . tab. . fig. . ottone . ottone . tab. ▪ fig. . ⅛ di brac. brac. ½ tab. . fig. . tab. . fig. . brac. stato naturale . salto dell immersione . abbassamento . quiete . sollevamento . salto dell agghiacciamento . tab. . fig. . acqua di fiori di mortella acqua rosa . acqua di fiori di aranci . aqua di frauole . acqua di cannella . acqua di neve strutta . acqua della ficoncella . vini rosso di chianti . muscadello bianco . aceto bianco . agro di limoni . spirito di vitriolo . olio . notes for div a -e piombo stagno rame ferro oro argento . acquarzente . bicchieri ▪ tazze sparse . notes for div a -e tab. . fig. . smalto . armilla di branzo . tab. . fig. , & . tab. . fig. . fig. . tab. . fig. . brac. ciambella . stagno . tab. . fig. . minugia . tab. . fig. . tab. . fig. . minugie . rame ricotto . ottone . tab. . fig. . tab. . fig. . tab. . fig. . notes for div a -e tab. . fig. . rame . tab. . fig. . brac. . tab. . fig. . notes for div a -e tab. . fig. . tab. . fig. . tab. . fig. . tab. . fig. . notes for div a -e tab. . fig. . tab. . fig. . notes for div a -e ambra gialla . cera lacca . diamante . zaffiro bianco smeraldo . topazio bianco . ambra bianca e nera . lapis lazzali , turchine , diaspre , agate , coralli , perle , metalli , lapilli de sali . saggina . bassilico . gruppiti tavole . notes for div a -e olio di tartaro e d' anici . sp. di zolfo . tinctur● di rose rosse . safferano verde giglio . vinato . lacca muffa . notes for div a -e moschetto . artiglieria . spingarda . smeriglio mezzo-cannone . spingarda . mastio . notes for div a -e dialog . d . de sistemi colubrina . falconetto . brac their mile is about f. colubrinetta . fasciate . ignude . archibuso dialogo del trattato delle nuove scienze . pettabotta . danari br. balestrone . br. . br. . br. . br. . ½ notes for div a -e tab. . fig. . ½ br. vetriole . sal nitre sal armoniaco . cold ebullition . acquarzente . sp. di vetriolo . olio di tartaro . sp. di zolfo . notes for div a -e olio dicera quintes . di zolfo . estratt . dorina di cavallo . sp. di cedrato . starna notes for div a -e pag. . edit . lugd. . acquarzente . pastiglia . balsamo bianco , &c. experimenta & observationes physicæ wherein are briefly treated of several subjects relating to natural philosophy in an experimental way : to which is added, a small collection of strange reports / by the honourable robert boyle ... boyle, robert, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing b estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) experimenta & observationes physicæ wherein are briefly treated of several subjects relating to natural philosophy in an experimental way : to which is added, a small collection of strange reports / by the honourable robert boyle ... boyle, robert, - . [ ], , [ ], p. printed for john taylor ... and john wyat ..., london : . errata: p. [ ] at beginning. advertisements on p. [ ]. reproduction of original in yale university library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - derek lee sampled and proofread - derek lee text and markup reviewed and edited - pfs batch review (qc) and xml conversion errata . page . for omitted , r. emitted , p. . l. . of left out . advertisement . books published by the honourable robert boyle , and printed for john taylor at the ship in st. paul's church-yard . . a free inquiry into the vulgarly receiv'd notion of nature , made in an essay adress'd to a friend : in english and latin. . the martyrdom of theodora and dydimus . . a disquisition about the final causes of natural things ; wherein it is inquir'd , whether , and ( if at all ) with what cautions a naturalist should admit them ? to which are subjoyn'd , by way of appendix , some uncommon observations about vitiated sight . . the christian virtuoso : shewing that by being addicted to experimental philosophy , a man is rather assisted , than indispos'd to be a good christian ; to which are subjoyn'd : st . a discourse about the distinction that represents some things as above reason , but not contrary to reason . . the first chapters of a discourse , intituled greatness of mind promoted by christianity . printed for j. taylor at the ship ; and j. wyat at the rose in st. paul's church-yard . experimenta & observationes physicae : wherein are briefly treated of several subjects relating to natural philosophy in an experimental way . to which is added , a small collection of strange reports . by the honourable robert boyle , fellow of the royal society . london , printed for iohn taylor at the ship , and iohn wyat at the rose in s. paul's church-yard . mdcxci . a letter that may serve for a preamble . to my learned friend mr. h. oldenburg ( secretary to the royal society . ) sir , being at length come to a resolution , i have already done something more than barely entred upon that way of writing , that you and i have more than once discoursed of together ; and wherein you particularly ( tho not you only ) among my learned friends , have wish'd to see me engaged . 't is not , that i am insensible of the prejudice which the things i deliver are like to sustain , by the disadvantageous dress wherein they must appear , in the way of writing i have pitch'd upon ; which being for the most part plainly historical , and set down in the order wherein , they chanc'd to come to hand , denies most of them , not only the usual ornaments of other books , but the allowable advantages , that method , elaborate discourses , neat hypotheses , and subtil disputes , are permitted to bring even to philosophical writings . but these considerations were over-sway'd by a sad one , founded upon the ( yet continuing ) condition i was in , when i was debating this matter in my thoughts . for it having pleased god ( to whose always most just dispensations men ought entirely to submit ) to afflict me with the stone and the palsy ; as on one side , these , added to a sufficient number of avocations , scarce permit me any great expectation , of finishing in a short time the tracts i had made a lesser or greater progress in , according to my first design ; so on the other side , my friends judging it unfit , that the materials provided for these more than begun treatises , should be quite lost , or kept too long useless , it seemed expedient , that as opportunity should from time to time serve , i should look over my memorials , and other scatter'd papers , to take notice what experiments and observations were to be found in them . upon these , and the like inducements , having pick'd up several of my dispersed papers , some of them written many years ago , and some of a less ancient date ; i began to refer the most part of what i found historical in them , together with some few things that did seem necessary not to be sever'd from them , to certain heads or titles which i called chapters ; and made them the more numerous , that they might singly be the less prolix : and about these i must desire your leave to represent some things , by way of preface . and first , several of the ensuing particulars that i met with among my papers , being parts of essays of other discourses , and being for hast transcribed for the most part verbatim , as they were couched there ; i dare hope for your excuse , if among such transcripts you now and then meet with things , which , how pertinent soever to the tracts they first belong'd to , might have been spared as needless , if not sometimes forein ; also , in the new form the discourses are now put into ; since i could not leave out such unnecessary clauses ( whereof yet i hope you will not find many ) without too much mutilating the coherence , or obscuring the sense of what is delivered ; and i could not alter them , and adapt others to supply their places without spending more time , and taking more pains , than in the condition i am now in , i suppose you would be willing to condemn me to . next , i despair not but you will allow me the liberty i have taken , to vary the bulk and method of particular chapters , as my occasions would permit , or the plenty or paucity of materials suggested ; or the nature of the thing i treated of , and the scope i proposed to my self in writing of it , seem'd to require . but sometimes my want of health and leisure , and my desire to hasten to other subjects , that either pleased me better , or seem'd more considerable , made some of the following chapters , compared with others , but short ; especially , if i were supplyed but with a number of things pertinent to that subject , by the papers i had then in hand , how much soever i may have written of it in other papers , which i hope hereafter to be master of . and this advertisement may render you a reason why to the title of some of the chapters i have subjoyned the first section , tho it be not at present followed with a second . and , as for my having imployed very differing methods in some of the ensuing . tracts , i did it with design , as judging such a variety of method more conducive to my purpose , than uniformity in it would have been . for , besides that some of the treatises , vhence these chapters were taken , did , by the ways wherein they were already written , oblige me , to accommodate my self to their method ; i thought , that if you should shew these papers to any , that are very unacquainted ( which i have heard you complain , that too many are ) with the way of accommodating in some tolerable manner , his enquiries and his writings to the several subjects he applies himself to , he may be somewhat helped , by the differing examples he may here meet with , to make variations somewhat suitable to the differing natures of the subjects he deals with . but here i must beg you to take notice , that , tho in compliance with this design , as well as for some other reasons , i have in several of the following chapters given intimations and hints of things , which i do not there prosecute ; and now and then propose some conjectures and opinions , whose proof i do not insist on ; yet i am not willing you should think , that , however some of those passages may be but occasional things , mentioned principally to excite , and give hints to the inquisitive and sagacious ; yet all , or most of them , are of the same kind ; and that i thought not on them , but as slightly and transiently as i mentioned them ; and have no better and other reasons to alledg for my suspicions or intimations , or even for my conjectures or my opinions , than those you will meet with in papers hastily drawn up ; especially since , i think , i can shew you divers of the things deliver'd in those passages , enlarg'd and render'd at least probable or practicable in other discourses , that for certain reasons do not accompany these i now send you . i expect , that you should think it somewhat strange , to find many of the following experiments set down much less circumstantially than those that are mentioned in the physico-mechanical experiments touching the air ; in the continuation of them ; in the history of cold , and in some other books of mine that you have been pleas'd to peruse . but on this occasion give me leave to represent to you , that the nature of divers of the former experiments , especially chymical ones , and my aims in mentioning them , being considered , it seem'd not requisite they should be more fully treated of : and as for others , tho the brevity and dispatch ; which divers reasons made me propose to my self , had not forbidden me to amplify ; yet i daily feel my leisure , not to say my life too ; so torn piece●●●● from me , by sickness , visits , business , and inevitable avocations , that i am frequently admonished to hasten the securing of as much as conveniently i can , by dispatching particular subjects , and am quite hundred from dwelling so long upon them , as , if i had more health and leisure , i should willingly do . to these things perhaps , so favourable a person as mr. oldenburg will add , that the characters which learned writers , english and forein , tho divers of them personally unknown to me , have been pleased to give of the diligence and sincerity employed in setting down the physico-mechanical experiments , and those of some other writings of mine , may permit me to hope , that it will be thought , that , after having been divers years vers'd in making tryals and experiments , i have made them with some care and wariness , and mentioned them faithfully , where i have not done it amply ; upon hopes it may be taken in good part from a person in my present condition , that was never a professor of philosophy , nor so much as a gown-man ; to have made shift to make the experiments and observations he communicates , and set them down truly and candidly , without fraudulently concealing any part of them , for fear they should make against him . and tho perhaps you will easily believe , that in divers of the experiments which i have but briefly mention'd , i have been as diligent an observer of circumstances , as i was wont to be when i made those , which have had the luck to be taken notice of for being fully related ; and tho it may be also , that some scruples or objections , which my brevity may in part occasion , were not unforeseen by me , and might have been avoided by a more copious and diffus'd way of writing ; yet i purposely decline such a way of delivering things , not only for the reasons above mention'd ; and because i suppose them that may peruse these papers , to be acquainted with my formerly published writings , and to have either from them , or otherwise , understood the way of making such experiments as mine ; but also , because , tho i wanted time and health , much less than i do , i should not think it fit too much to prevent the industry of others about the tryals i mention ; and reap the field so clean , as not to leave them , not only store of ears to glean , but some corners of standing corn. i have therefore here and there purposely omitted , both , some not absolutely necessary practical directions about making of tryals , that might prevent such scruples or objections , as have the grounds of answering them clearly deliver'd in my printed books ; and several , not only lesser circumstances , but considerable phaenomena , and obvious applications , that may probably occur to others , as they did to me in making the tryals and reflecting on them . advertisements about the disposition of the following treatise . yov will quickly discern that the following chapters could not be intended for compleat tracts , about the subjects handl'd in them . and indeed they were intended but for such memoirs about the various particular subjects they treat of , as may be serviceable to the solid natural history that has been nobly design'd and is still prosecuted , by the royal society . wherefore since ( at least in our age ) no writer that i know of , has so early and so well , both urg'd the necessity of natural history , and promoted divers parts of it by precepts and specimens , as the illustrious lord verulam ; i shall not scruple in the way or manner of writing these short collections of mine , to make use somewhat frequently of his authority and examples ; but without confining my self to either . i. agreeably to this advertisement you will find , that some of the particulars that the following treatise consists of , are single and as it were , independent ones ; upon which account they resemble those which in the verulamian sylva , or natural history , are call'd experiments solitary : and have for that reason induc'd me to give that title to each of the several chapters that are made up of them . ii. another sort of chapters there is , wherein divers experiments and observations , all of them relating to the same subject or purpose , are set down together . these if they were rang'd and sorted in order to distinct theories , i should call , in imitation of the mention'd author , experiments in consort . but my backwardness to frame theories has made me chuse to forbear as yet to methodize them , and therefore has made me think fit to call them only various experiments and observations about this or that subject ( which they belong to . ) iii. my hast , tho not that only , induc'd me to make one sort of chapters more , that partly agrees with , and partly differs from each of the two that i come from mentioning : for in every one of these chapters , there are two or three , if not more , single or solitary experiments ; and there are also others that have some kind of connexion among themselves , as being referable to the same subject or purpose . on that score the title that is given to each of the chapters of this third sort , is that of miscellaneous experiments ; and sometimes ( but seldomer ) of promiscuous ones . and all the particulars that i refer to the three foremention'd heads , are cast into chapters , wherein the several kinds are distinguish'd only by their titles , or not . iv. there is one advertisement that regards all the sorts of particulars that are refer'd to the foremention'd chapters , which is , that i have usually comprehended observations , as well as tryals , nuder the title of experiments ; which i have done , not only upon the authority , and in following the example of our judicious chancellor ( as is every where obvious in his sylva sylvarum ) but for other reasons too . for both the sorts of particulars may pass for matters of fact , and so are historical , taking the word in a lax sense , and the imploying it in that sense , makes the articles or passages , whereof the chapters and other parts of our collection consists , much more commodious for references and citations . v. besides the three foremention'd kinds of chapters , you will meet in the ensuing treatise with another sort of writings , whereof some are almost entire , and others fragments of larger discourses . in neither of these , i did confine my self so much to matters of fact , as in those chapters that consist of experiments and observations ; but took the liberty , as occasion requir'd , to inlarge in discourses , and sometimes to cite such passages out of other mens writings , as i judg'd i could make some pertinent application or use of , perhaps unthought of by the author . and these papers being most , if not all of them written in a more free and discursive way , i thought fit to separate them from the sets of collections that are almost merely historical ; and accordingly i have not styl'd them chapters , but titles ; and have forborn to assign them , as i did the others , ordinal numbers ; which i desire likewise you would not prefix to any of them , because i am not yet resolv'd how i shall dispose of them , either by supplying what is wanting to finish any one , or more of them , or by taking to pieces , and imploying those pieces as materials for other tracts . vi. perhaps i shall not be thought to need pardon , if to comply with their curiosity , who affect most those experiments , that are either uncommon , or teach them to do or perform something useful or pretty ; i sometimes prefix a title declaring what it treats of , to a particular experiment ( or observation , ) which for its importance , novelty , or vsefulness ( theorical or practical ) may deserve to bedistinguish't ; since by this means such particulars may be the better imprest on the memory , to gratifie those , whose nicety or want of leisure , may make them well pleas'd by a transient view of the titles we speak of , to find such passages as they chiefly look'd for , with less trouble than that of perusing an index . vii . among the experiments our collection consists of , there is here and there one , to which it was thought fit to add something , either by way of explication , or of illustration , or of confirmation , or of answer to objections , or of theorical reflection , or of practical application , &c. and these supplements or additions it was thought fit to call sometimes annotations , but oftner scholiums , because that term is freely us'd in a very comprehensive sense by mathematical writers . but tho i readily acknowledg that this term has been chiefly imploy'd by mathematicians , yet the use of it has not been so confin'd to them , but that good authors in other parts of learning have not scrupl'd to imploy it , as may appear by the scholiums that some learned physicians have written upon hollerius , an eminent person of their profession ; as also by the example of the famous and experienc'd forestus , who has not seldom subjoin'd scholiums , even to his own medicinal observations . viii . the mention of these scholia prompts me to tell you , i had almost forgotten , but yet must not leave unmention'd , that i thought fit now and then to premise to sets of experiments , and sometimes ( tho more seldom ) to a single observation a short preamble by way of introduction , which may often excuse the need of subjoyning a scholium ; and may be warranted by the example of the lord verulam in his centuries , wherein he often inserts such short preambles , as things fitted to give light to the experiments they belong to , and to give some advertisement both of the nature and importance of the subject , and of the scope of the writer , or of other useful circumstances . ix . if among my own experiments , namely , those that i have made or seen , i have sometimes inserted experiments or observations that are not so : i have not done it without reason , and am authoris'd in that practice , by frequent examples afforded me by the first , if not only author that i know of , that gave us a set of precepts of well writing natural history , our often cited verulam , whose centuries do in great part consist of borrow'd experiments and observations ; without which , he was sensible that his sylva must be of too narrow a compass , or too thinly stock't with plants , especially with trees . and indeed 't is not to be expected , that , as the silk-worm draws her whole mansion altogether out of her own bowels , so a single man should be able to write a natural history out of his own experiments and thoughts . and he that will strictly confine himself to those , will be often reduc'd to omit things very pertinent , if not necessary , to his subject , which is of practice studiously declin'd by me , who prefer the readers vtility , to the ambition'd glory of being thought to borrow nothing from any body . and i can add in my defence , at least my excuse , that i have made use but of a small part of the liberty allow'd me by the example of so great a guide in the way of writing natural history . for i have very much seldomer than he , employ'd the tryals of others ; and have yet seldomer mention'd unverifi'd reports or vulgar traditions , being careful that the bulk of the matters of fact i deliver , should consist of things , whereof i was my self an actor , or an eye witness ; and that the comparatively few borrow'd experiments that i added , ( that i might not deprive my reader of some things very pertinent and useful to my subject ) were receiv'd from persons of very good credit ; besides that i do not only frequently give sufficient intimation in the experiment or observation its self , but oftentimes by placing the letter c in the margent , do give notice ; nay , and sometimes to a whole set , prefix the title of communicated experiments or observations . x. i have nothing more to give you notice of here , save that , whereas you will find that i write but on one side of the leaves , whereof this book * consists : i did so for two reasons . the first , that in case i should have occasion to imploy any of these experiments in other treatises , for which i am more concern'd than for this rhapsody , i might have room to substitute , if it should be thought fit , one or more of my later experiments in its place . and secondly , that i might have room , if i can get leisure , to write annotations , or make reflections , or illustrations , or corrections , or in a word , such addititions and alterations of particular experiments and passages , as they shall be thought to deserve or need . i am sensible that this preamble , increas'd by the advertisements that 't was thought necessary to annex to it , is of a length that may seem disproportionate to the book or tract 't is prefixt to . but i may in excuse of this represent to you , that the bundle of writings you now receive , is but a part of the book ; to which , if god vouchsafe me health and leisure , this preface inlarg'd by its appendix , is design'd for an introduction . and in that case 't is hop'd that these preliminaries , as many as they are , will not be thought impertinent , or needlesly prolix . experimenta & observationes physicae . tome i. chap. i. containing chymico-magnetical experiments and observations . the loadstone , pyrophilus , is so admirable a body , and its usefulness to mankind is already so great , without denying us hopes of farther improvments ; that i think we must want curiosity or gratitude , if we neglect either to take notice of any experienc'd phoenomena that directly relate to so abstruse a subject , or , by consigning them to paper , to preserve them from oblivion . 't is chiefly by this consideration , pyrophilus , that i am induc'd to mention to you the following experiments and observations , made most of them by the help of the fire . for , tho some of them may seem but slight ; yet they may not prove unuseful , towards discovering the nature of a body so strange and singular , that , for ought is yet manifest , any true magnetical phoenomena may somewhat conduce to the knowledg of it , and i was the rather induc'd to make tryals and observations of this kind , because most of them are such as i have not met with in authors . and the few that remain , i have not found sufficiently taken notice of there ; philosophers and mathematicians ayming chiefly , in their magnetical writings , to prosecute and apply the attractive and directive , and perhaps the inclinatory , faculty of the loadstone . whereas , throwing into another paper , what i observ'd , of that kind , i did in the present inquiry mainly intend to make the loadstone rather the object than the instrument of my tryals : and handling chiefly the very substance of the stone , endeavour not so much to advance or apply its faculties , as to weaken and destroy them , tho in order to the better knowing of them . having therefore procured a considerable number of , for the most part naked ( or uncapt ) loadstones , most of them course , but of differing sizes , shapes , colours , and countries ; i made upon them several tryals , some of which i should immediately proceed to give you a brief account of , but that 't will be proper to premise this short advertisement : that , i would not have the title of these experiments make you expect , that the fire should be a main agent in every one of them , since to preserve some few of them , i refer them hither , tho an actual fire was not imploy'd to make them : since the common rule that a potiori parte fit denominatio , will suffice to warrant , or at least excuse , my giving to this small collection the title of chymico-magnetical experiments ; because the greatest part were perform'd by the help of the fire , or bodies chymically prepar'd by the application of it . and because 't is usual with the best writers about magnetism , to reckon steel and iron among magnetical bodies ; i shall not scruple to deliver in this paper some experiments , made by the help of the fire upon those subjects ; with reference neverthe less to magnetism . experiment i. having ignited several loadstones , and removed them from the fire till they grew cold again , i found a great disparity in the visible substance whereof they consisted , and the manifest structure of the gross parts that made them up . for some stones upon refrigeration , either fell asunder of themselves , or grew very brittle ; when as others still continued in their entireness : some of them being broken look'd not unlike iron-ore , or stones which i have gather'd near iron-mynes in kent ; others being broken , after refrigeration appear'd to consist of plates or flakes of several colours , and lying parallel to one another : and others again , which as i remember were english ones , did neither appear to be compos'd of any such flakes , nor had their dark colours much , if at all chang'd by the operation of the fire , nor did cease to be solid bodies . experiment ii. we could not upon the burning of several small loadstones one after another , discern any such blew sulphureous flame as porta in his natural magick relates himself to have seen , and judges to have been as it were the soul of the loadstone , upon whose recess he says , it lost its magnetick faculty , which is most commonly true as to any considerable degree of the coitive or attractive power , but not of the directive faculty or vertue . but it may be that porta mistook the small flame , which is often omitted even by well-kindled and glowing charcoales , ( on which sort his loadstone was placed ) especially when a little blowen upon , for the exhaling soul of the loadstone ; or else , to be civil to him , we may suppose , that , his stone was more rich in unctuous moisture than others are wont to be ; and if we had had by us a very exact pair of scales , we should have endeavoured to have by them discovered , whether the fire do deprive loadstones of any ponderable parts . experiment iii. the solidity of some english loadstones , made me think it fit , tho i look'd upon them as a kind of iron-ore , to try whether they could not be brought to strike fire . and accordingly , having made divers collisions betwixt a rough peice , and the steel of a tinder box ; i found that with much ado it was possible to obtain some sparks , ( tho they seem'd but small ones : ) but having taken a large peice of smooth loadstone , i found that , by striking it somewhat briskly , with the edge of a steel'd hammer , we were able to produce good store of sparks , and some of them of a surprizing bigness ; for they were judged to exceed the size of those that are usually afforded by common flints . experiment iv. for certain reasons i thought fit to make a further tryal , being desirous to satisfie my self , whether it were not possible , to make loadstones afford fire without the help of iron or steel . and being willing to comply with this curiosity , i made choice of two solid peices of loadstone , that were cut almost into the form of cubes ; and found that many collisions being made between them , especially at the edges ; there were produced from time to time , ( tho not frequently , ) some sparks of fire , tho neither so numerous , nor so great or vivid , as those of the foregoing experiment wherein the steel was employ'd . experiment v. i have ( elsewhere ) formerly related , that if an oblong loadstone made glowing hot , be refrigerated perpendicularly , the lower extream will thereby become its northern pole. and i shall now add , that yet if such a loadstone be refrigerated perpendicularly , not upon an ordinary terrestrial body , but upon the northern extream of a much stronger loadstone ; in such case , this debilitated stone will receive its impressions , as if it were an iron , and its lower extream will not be , as before , by the magnetick effluvia of the earth , made its northern pole ; but it will be contrariwise animated by the pole of the loadstone , on which 't is cool'd ; and according to the laws magnetical , the lower extream of it , will not be its northern , but its southern pole , nimbly attracting the north end of an excited and aequilibrated needle . experiment vi. by the forementioned way of refrigeration i also found , that a disanimated loadstone ( if i may so speak ) may be restored , to some degree of its attractive vertue ; for i try'd that a small loadstone , which after its being made red hot in the fire , and cool'd perpendicularly upon the ground , was not able to take up a fragment of a needle ; being again heated , and not only cool'd upon the pole of a strong loadstone , but suffered to rest on it a while after , was soon grown vigorous enough , to take up what formerly it could not move . experiment vii . i further observ'd , that tho a loadstone that had pass'd the fire , had not , by being immediately before made red hot , had its body open'd and fitted to take in plentifully the magnetical streams ; yet it would , like a wire of iron , acquire a new verticity from the vigorous loadstone ; but not be in many hours so vigorously impregnated with magnetick vertue , if it were applied cold to the pole of the animating loadstone ; as it would in a very short time , if being glowing hot it were refrigerated thereupon . n. b. it has been observ'd , that if a loadstone be made red hot in the fire , it will scarce retain any sensible attractive vertue , save that it will be able , by being endowed with a magnetism from the earth , to drive away that pole of a needle well poys'd , which agrees in denomination with that pole of the loadstone , which is applied to it . but i desire that it may be remembred , that i intimated that this is not strictly and universally true ; for in some of our english loadstones , it has been observ'd , that ignition does not only leave them capable of a directive vertue , but leaves them also a considerable attractive power , so that they will sustain a good weight of steel ( as will appear hereafter . ) experiment viii . we took three english loadstones that appeared to be of a very compact substance ; two of them very small , as not being of near half an inch in length ; the other much greater , being about an inch long , and of a considerable breadth , but yet of small thickness : these we made red hot in a fire of well kindled charcoal , and being thorowly ignited , removed them one after another , and hastily set each of them upon a plate of silver ( for neither wood nor iron would have been convenient ) and applying the loadstone ( capp'd ) to each of them , whilst it was yet red hot ; it seem'd manifest enough , not only , that whilst it was in that state , the stone had not so strong an operation on it , as if it were not red hot : but , which is remarkable , when it ceas'd to appear ignited , but yet was intensly hot , ( so that it was readily able to burn his fingers that should offer to take it up between them ) the armed loadstone had a more powerful operation on it , by way of what they call attraction and sustentation ( not only , as i said , than it had , whilst the ignited stone conspicuously retain'd the colour fire , but ) than it had , after the same stone was grown cold . experiment ix . this experiment was reiterated with the two smaller magnets and the greater , with the like success : and when the magnets were grown cold , they did notwithstanding their having been twice ignited , discover some little magnetism , if apply'd to the end of a well-excited magnetick needle , nicely poys'd upon the point of an ordinary needle [ or brass pin ] ( on which its center of gravity lean'd . ) and i found that the bigger of the three forementioned loadstones , after the first , if not also after the second ignition ; did not only move the magnetick needle more briskly than one would have expected , but , ( which may seem strange ) being thrust into filings of mars , and then taken out , it carried up with it and sustained a considerable number of them . whence we may conclude , that in some loadstones of a very solid constitution , such as this was ; the magnetical vertue is more radicated ( if i may so speak ) or permanent , than in the generality of other magneticks : this stone being the first wherein i observ'd , after i had thorowly ignited it , any attractive vertue able to take up filings of iron . experiment x. on occasion of these tryals i made another , which tho to some it may seem but slight , i thought the more worthy to be made , because i remember not to have read or heard of it before ; we took then , the same loadstone that we employ'd about the last experiment , and having again made it red hot , in the fire , suffered it not to cool leisurely in the air , as before , but quenched it , in a bason of cold water ; intending thereby to make a double variation of the experiment , first , by cooling it hastily , and as it were abruptly ; and next by cooling it not in the air , but in a fluid some hundreds of times more dense or ponderous than the air. the event of the tryal was , that , upon the immersion of the red hot stone , there fell off some flaky matter , as if it had been scales of mars ; and the stone , when cold , would not take up any filings of iron , as before it did many ; so that it appear'd to have lost much of the vertue it so lately had , tho it retain'd the power to move a well-poys'd needle , if it were held near to either side of the point of it . experiment xi . a black oblong loadstone , of a homogeneous substance , and weighing near three drams , having been in a fire of well-kindled charcoals , ignited , and continued so for some minutes , of an hour ; being weighed again as soon as it was cool'd , was found to have lost about ⅝ of a grain of its first weight , and much of the blackness of its colour . tho the affinity between the loadstone and iron , might make one expect that the fire might have a like operation upon this stone , and that out of which iron is commonly melted , both being indeed iron-oars ; yet for some reasons that i cannot now stay to mention , i was induc'd to think , that the effect of ignition upon those two bodies might be very differing , as i conceive their internal and unseen texture to be . and therefore i made the following experiment . a lump of iron oar , which look'd almost like a white stone , rather than a common oar , and was about the bigness of two eggs ; being apply'd , in several of its parts , to an excited needle , did not appear to move it manifestly . but being afterwards made glowing hot , and kept so for a while , and then refrigerated ; it did in those parts , which seem'd by their newly acquir'd colour to abound with metalline corpuscles ; it did , i say , manifestly attract the north end of the needle . and this was tryed , both with a needle of our own touching , and by the mariners needle of a sun-dyal ; whos 's flower-de-luce , the burnt oar did manifestly draw . experiment xii . to confirm the former observation , and also what i elsewhere gave notice of , that divers bodies are of a magnetical nature or have in them some parts that are so , which yet are not vulgarly believ'd to be referable to that sort of bodies ; i shall subjoyn the following experiment . a brick that had not been us'd , was saw'd long ways into two equal pieces , and each of these ( one at one time , and another at another ) was heated red hot in the fire for a pretty while , and afterwards suffer'd to cool north and south : and , as i expected , it thereby acquired a magnetical verticity ; and with that end that in cooling respected the south , did a little , tho but faintly , draw the flower de luce ( which pointed out the north ) of the mariner's needle ; and with the other end , did somewhat more vigorously drive the flower de luce away , and a little attract the other extream of the needle . experiment xiii . we took a [ black ] loadstone , and having by degrees beaten it small , without suffering it to touch any iron or steel vesiel or instrument , [ which because of the hardness of the stone , was very troublesome to do ; ] we set aside the grosser grains for other uses , and upon some of the finer powder we pour'd the spirit of common salt , which had at first a sensible operation upon it , by producing foetid fumes , and making a kind of ebullition , as that menstruun is wont to do upon filings of iron or steel . but nevertheless , being kept a night or two in digestion , it drew a high tincture ; and tho this was not at all , like the solutions of mars in spirit of salt , green , but of a yellowish brown , not very remote from redness : yet a little of it being dropt into a fresh and sufficiently coloured infusion of galls , turned it presently into an inky substance , which in some positions appear'd blewish , as a tincture or light solution of mars would have done .. i shall only add , about the solution of loadstone , that having carefully made it with a good aqua regia , obtain'd a solution , some of which you may yet command a sight of , that by some virtuosi to whom i shew'd it , was thought either a fine solution of gold , or little , if at all , inferior to it in kind or richness of colour . i chose to employ the spirit of salt , rather than that of nitre or aqua fortis , in this experiment ; because i found the first named liquor to dissolve iron very well , if not better , tho less furiously , than aqua fortis it self ; and also , because i could by this means better judge of the tincture of its colour ; having formerly found by tryal , that spirit of salt makes a green solution of mars ; but aqua fortis or spirit of nitre , a reddish one . and it was to judge of the tincture of the loadstone , as well as for another purpose , that i was so careful to keep the stone from touching iron , when it was pulverising ; least by the hardness of it , and the sharpness of its angles , it should grate off some parts of the metal , and so alter the solution ; for want of which caution , i have known some experiments about artificial gems to miscarry ; the brass morter wherein the hard ingredients were beaten , having communicated some particles to them , that alter'd the colour which the masse after vitrification would otherwise have been of . experiment xiv . some parts of the foregoing experiment may be confirm'd by that which follows . i caus'd a weak loadstone to be heated red hot , to make it the more easie to be powder'd , and having caus'd it to be beaten very fine , i digested good spirit of salt upon it . ( i afterwards found that ordinary spirit would serve the turn ) this in a few hours acquir'd a tincture not greenish , but almost like that of a troubled solution of gold. it strongly relish'd of iron , and a little of it being dropp'd into infusion of galls , it turn'd it immediately into an inky liquor ; part of this solution being gently evaporate ● , grew thick like an extract , but did not seem dispos'd to shoot into chrystals ; yet another part of it did precipitate with salt of tartar , much like a solution of vitriol ; and another with spirit of fermented urine gave a plentiful , but yellowish red , praecipitate . experiment xv. meeting among my loose notes , with one that may serve both for a variation and confirmation of what has been above delivered in the experiments ; it seem'd not improper to annex a transcript of it . a red mineral , whose consistence was between stony and earthy , was by me judg'd to be a kind of iron oar , tho having powder'd some of it , i could not find that a good loadstone would attract any part of it : therefore , to satisfie my self , and to confirm d. b's observation ; about the vertue of linseed oyl , i caus'd this red powder , wetted with that liquor , to be kept about two hours ignited in a crucible ; by which means it was turn'd blackish . this dark colour'd powder was taken out , and suffer'd to cool , and then would readily adhere to the same loadstone , almost as if they had been a heap of filings of iron . but the operation of the fire perhaps contributed , as much ( or more ) as the linseed oyl , to this change. for a parcel of the red powder being kept ignited in a crucible , tho without the liquor , did afterwards appear magnetical . after having said thus much of the most useful of uncommon stones , the magnet : it will not , i presume , be thought incongruous to subjoin some remarks about the most precious of them that are known among us , viz. diamonds ; which will be done in the next chapter . chap. ii. containing various observations about diamonds . diamonds being generally esteem'd the most noble and precious of gems , and even of inanimate bodies here below , ( for of carbuncles , the very existence is disputed ; ) the opportunity i had of being one of the committee or directors of the english east-india company , ( whereto the desire of knowledge , not profit , drew me ) allow'd me in some measure to gratifie my curiosity about them , by adding to some observations of my own , the answers i had to the questions , i propounded to some east-india merchants and jewellers , that had opportunity to deal much with those gems . part of what i had learn'd about them , i committed from time to time to some papers , which were the main things that supply'd me with the following particulars . these gems , ( to add that upon the by , ) may the rather deserve our curiosity , because the commerce they help to maintain between the western and eastern parts of the world , is very considerable . for as small as their bulk is , their properties and mens opinion , do so much recommend them , that i remember one of the most famous and intelligent merchants of this nation , ( who has been governor of more than one trading company in it , ) being enquir'd of by me about the value of the diamond trade ; he answer'd me , that according to his well-grounded estimate , there came from the east-indies into europe , one year with another , to the value of about sterl . of which about l. came into england ; which at present , because of the prudent indulgence of the government , and of the east-india company , is become the mart of diamonds . i. to prove the great hardness of diamonds , even in comparison of other bodies , that are thought wonderfully hard , a famous artist for cutting of diamonds , in return to some questions i put him , affirm'd to me , that he could not either cut or polish diamonds with any thing but with diamonds . and he further answered me , that if he should employ so rough a way , and such forcible engines to cut rubies or any other stones , as he does to cut diamonds , it would presently break them in pieces ; which the inspection of his engine made very probable to me . ii. a very skilful cutter and polisher of diamonds ( mr. l. ) being demanded by me , whether he found that all sorts of diamonds were of equal hardness , told me , that having dealt in diamonds near twenty years in amsterdam , and divers years in england , he perceiv'd that there are of later years , brought over worse and worse sorts of diamonds ; so that he judges those of the old rock ( as he calls them ) either to be quite spent in the indies themselves , or at least to be seldom or never brought over to us . and he finds several of recent diamonds , so soft and brittle in comparison of those of the old rock , that he is oftentimes afraid , or unwilling to meddle with them , least he should spoil them in the cutting or polishing . iii. notwithstanding the ( lately mention'd ) wonderful hardness of diamonds , there is no truth in the tradition , as generally as 't is receiv'd , that represents diamonds as uncapable of being broken by any external force , unless they be soften'd by being steep'd in the blood of a goat . for this odd assertion , i find to be contradicted by frequent practice of diamond cutters : and particularly having enquir'd of one of them , to whom abundance of those gems are brought to be fitted for the jeweller and goldsmith , he assur'd me , that he makes much of his powder to polish diamonds with , only , by beating board diamonds ( as they call them ) in a steel or iron morter , and that he has that way made with ease , some hundreds of carrats of diamond dust . iv. 't is an opinion receiv'd among many that deal in gems , that as diamonds are the hardest of bodies , so the same compactness , and their great solidity , gives them also a proportionable gravity , and makes them extreamly weighty , in reference to their bulk : and i saw in the hands of a virtuoso , a book ( that i could not procure ) not long since put out by a french jeweller , who as he affirms , has dealt very much in diamonds ; wherein the author asserts , the great ponderosity of these stones , in comparison of other bodies . but this opinion agrees very little with the following experiment , that i find among others , that i try'd about gems , register'd to this purpose . a rough diamond somewhat dark within , did in a pair of scales that would turn either way with the th part of a grain , weigh grains , and eight sixteenths . this stone being with care weigh'd in water , according to the rules of the hydrostaticks ; its weight appear'd to be to that of an equal bulk of that liquor , as / to . so that , as far as can be judg'd by this tryal , even a diamond weighs not full thrice as much as water . v. a famous and experienc'd cutter of diamonds , being ask'd by me , whether he did not find some rough diamonds heavier than others of the same bigness , told me , that he did , especially if some of them were cloudy or foul : insomuch that shewing me a diamond that seem'd to be about the bigness of two ordinary pease or less , he affirm'd , that he sometimes found in diamonds of that bigness , compar'd together about a carrat ( or four grains ) difference in point of weight . vi. the shape or figure of diamonds is not so easie to be securely determin'd . for those that are seen in rings and other jewels , having been by way of preparation cut and polish'd , have chang'd their natural figures for that which the artificer thought fit to give them . and rough diamonds themselves ( which are not obviously met with ) do oftentimes come to our hands broken , tho unwillingly , by the diggers . and thereby unfit to acquaint us with their genuine shape , which we may also miss of being able to discover , on account of the accidents that the matter they consisted of was subject to , at their formation in the mine . for to omit other proofs , having had a parcel of between and ( if i misremember not the number , ) put into my hands at one time in the east-india house to gratifie my curiosity , i found very few of them compleatly shap'd ; but most of them broken , and of very irregular figures , like those of so much gravel taken up at adventures upon the sea-shore . but some few i saw that were pretty regularly figur'd , which probably were not much hinder'd from shooting freely in the wombs or cavities , wherein they were coagulated or concreted . and these seem'd to consist , in my opinion , of several triangular surfaces that were terminated in , or compos'd , diverse solid angles . and one rough diamond i had of my own , wherein this shape was more conspicuous than i remember to have seen in any other . besides having enquir'd of a very experienc'd artificer , who dealt much in fitting these gems for the goldsmiths use , whether he found rough diamonds to be of any constant figure , and if he did , what that figure was ? he answer'd me , that he always found those that had any constant , ( or as he meant , regular ) figure , to be in his own expression six corner'd . vii . diamonds have in them a grain ( or a determinate tendency of their fibres , or rather of the thin plates they are made up . of , ) as well as wood , and may with case enough be split along the grain , tho not against it ; as i have seen a very large diamond that was cut according to the grain into three pieces , whereof the middlemost , tho large and about the thickness of a shilling , was of an even thickness , and exactly flat on both sides . i have my self a diamond-ring , whose stone i would not have polish'd , but caus'd it to be set rough as nature produc'd it , because in that state the grain is manifest to the naked eye , and much more to a glass moderately magnifying the several plates it consists of , having their edges distinguishable like those of a book a little open'd . a cutter of these gems that has had store of them to practise his skill on , answer'd me , that one good blow may split even great diamonds , if it be given , as they speak , with the grain ; but against the grain , he affirm'd to me , as dexterous and expert an artificer as he is , that he is not able so much as to cut or polish them . viii . the common colour of diamond being generally enough known by sight , 't is not needful , as it would not be to describe it by words ; but the most usual colour of these gems is not the only , of which they may sometimes be found . a great traveller into the eastern parts of the world assur'd me , that he had seen some of them that were of a pale blewish colour : that famous french jeweller as well as traveller , monsieur tavernier , gives an account of a fair diamond that he had of a very red colour ; and that great . ornament of our english court the d. of r. told me , that she was mistress of a fair one , which tho not of a ruby , was of a red colour , but not having it at hand , she could not then shew it me : a relation of mine , in the same court , used to wear a diamond ring ; which tho the stone was not great , he valu'd at a hundred pound , because its colour was of so fine a golden yellow , that i i should have taken it for an excellent topaz , but that he had satisfi'd me 't was a diamond to which agreed its great hardness , which gave an uncommon luster . and i remember , that surveying attentively a parcel of rough diamonds newly brought from the east-indies , i perceiv'd among them , besides several lighter variations of colour . one stone that was all green , and that to such a degree , that i doubted not that if it were polish'd land set , it might pass for an excellent emerald ; and i should have suspected this gem to have been really of that kind , but that i found it among diamonds that belong'd to merchants too skilful in those gems to be impos'd upon ; and which was more , the stone being yet rough and uncut , i found it plainly to have the proper shape of a diamond . ix . at the late return of the ships from india , being present at the delivery of the diamonds to the owners , i observ'd one belonging to a dutch merchant whose father was a cutter of diamonds , and bred him to the same trade . the diamond came from the king of cholconda , it was shaped ( like mine ) with fix triangular sides , which yet were neither regularly figured nor truly flat , some of them being a little convex , and one of them having a manifest and odly-figured cavity in it . but the diamond being fair and flawless , and so thick , that the merchant told me it would be too deep for one ring , and that therefore he meant to split it into two . i had it weigh'd , and found it to amount to ten charats ( or grains ) . i could easily perceive the grain of this diamond , which the merchant also acknowledged ; who answer'd me , that he had never seen in diamonds any heterogeneous mixture inclosed . he further inform'd me , that there was brought him a large diamond from borneo , that was much darker than one i shewed him ; insomuch that he compared it to soot ; but when he had cut and polished it , he and others were much surprized to find it a fair and clear stone , of very great value . x. the conjecture i have elsewhere propos'd , that divers of the real virtues of gems may be probably deriv'd from the metalline , or mineral tinctures , or other corpuseles that were imbody'd with the matter of the gem , whilst it was yet fluid , or soft , and afterwards concoagulated therewith : this conjecture , i say , may be much countenanc'd by the following relation , which deserves a place in this chapter , by reason of its pertinency to the subject of it . i have long suspected that the matter whereof diamonds mainly consist was , whilst it was yet in solutis principiis , impregnated with metalline , and more particularly with martial ones : but by reason of the dearness of those gems , and some other impediments , tho i have ben master of several diamonds of differing sizes , cut , and uncut , yet i could never make a tryal capable of satisfying my curiosity , till having lately met with among other little curiosities that lay long neglected by me , some number of small diamonds , that i had bought for experiments ; i consider'd that their being yet rough , and so in their natural state might make them more fit for my purpose , and so it might that they were not so clear as those that we value in rings , which probably argued their having more of martial tincture in them than i should expect in the more diaphanous : upon this account , i say , i took a moderately vigorous loadstone ( for 't was none of the strongest i have had ) and apply'd it successively to five or six of these small stones , without perceiving it had any operation on them : but when i came to apply it to one more , which look't somewhat duller than almost any of the rest , i found that it had in it particles enough of an iron nature to make it a magnetical body ; and observ'd without surprise , that not only it would suffer it self to be taken up by the strongest pole of the loadstone , but when that pole was offer'd within a convenient distance , it would readily leap through the air to fasten it self to it . i have elsewhere mention'd some other qualities of diamonds , as besides their electrical vertue , this , that 't is possible that some of them may without fire or intense heat be brought to shine ; tho among all that i have try'd , i found but two that i could so make luminous . one of these belongs to the king , and is describ'd at the latter end of our history of colours ; and the other is a very small one of my own ; which either was quickly lost among other stones of the same size , or quickly lost its faculty of shining . but , to avoid repetitions , i shall here only add , that some few other observations of a more peculiar sort than those deliver'd in the two foregoing pentades , may be found in other writings of ours , to which they seem more properly to belong . chap. iii. many changes of colour produc'd by one simple ingredient . i know not any way more likely to convince the generality of men ( who are wont to be much more impress'd on by sensible phenomena than theories , tho solidly founded ) how great an interest the variable texture of bodies may have in making them appear of differing colours , than by shewing how the addition of a single ingredient that either is colour ess , or at least is not of any of the colours to be produced , is capable ( and that for the most part in a trice ) by introducing a secret change of the texture to make the body , 't is put to , appear sometimes of one colour , sometimes of another , according as the parts of the body wrought upon are dispos'd to receive such a change as modify's the incident beams of light after the manner requisite to make them exhibit a blew , a green , a red , or some other particular colour . upon this consideration i thought of several liquors , such as aqua fortis , oyl ( as they call it ) of vitriol , or instead of it of sulphur . aqua rezia , besides other saline liquors that i shall not now stay to name , because it may here suffice to tell you , that amongst them all i made choice of the spirit ( not that which chymists call the oyl ) of salt , as that which is very simple , and which if it be not too much dephlegm'd , may be had clear and colourless enough . with this spirit , i proceeded to make the following experiments upon several bodies , whose differing textures made me suppose they would be fit for my purpose . and tho i could not , without much disadvantaging my design , forbear to mention some tryals that may be found elsewhere scatterd among my writings on other occasions ; yet the greatest part by odds of those laid together in this chapter , will , i presume , be found new. i. some drops of well coloured syrup of violets being let fall together upon a piece of white paper , if a third or fourth part so much spirit of salt be with the tip of one's finger mix'd with them , the syrup will presently become of a red colour , usually somewhat inclining to purple . ii. but if the liquor to be acted on , be otherwise disposed , 't is possible with spirit of salt to turn it from a blew colour , not to a red , but to a green , as i have sometimes done by letting fall into a deep solution of filings of copper made with an urinous spirit , as that of sal armonia● , just as many drops of spirit of salt as were requisite and sufficient to produce the change intended . i say just so many drops , because a very small error either in excess or defect , may leave the mixture still blew , or bring it to be all colourless . iii. upon a quantity , not exceeding many drops of good syrup of violets , let fall two or three drops of good spirit of urine , harts-horn , or the like , or of oyl of tartar per deliquium ; and when by mixing them well , the syrup has acquired a fine green colour , then by putting to it a little of the spirit of salt , and stirring it with the tip of your finger , you may turn the green syrup ( as in the first experiment you did the blew ) into a red. iv. if you put a quantity of red rose leaves well dryed into a glass vial almost full of fair water , and soon after put to them as much spirit of salt as will make the water pretty sharp , you will quickly see both that liquor and the contain'd leaves brought to a fine and lovely red , which scarlet colour it will retain for a great while ; the like effect spirit of salt will have on some other vegetables of a stiptick or of an astringent nature . v. but if by infusing brazil in fair water , you make a tincture of it , which you may much deepen by droping into it a little spirit of harts-horn , or of urine ; if you then put to it a little spirit of salt , it will presently change it from a deeply reddish colour , oftentimes like that of muskadine , to a colour far more pale , or rather yellow , like that of the more dilute sack ; so that the same spirit acting upon two vegetable tinctures differingly dispos'd , draws out and heightens redness in one , and destroys it in the other . vi. if you make an infusion of true lignum nephriticum in spring water , it will appear of a deep colour , like that of oranges , when you place the vial between the window and your eye , and of a fine deep blew when you look on it with your eye placed between it and the window . but if you shake into this liquor a few drops of spirit of salt , the caeruleous colour will presently vanish and appear no more , in what light soever you look upon the vial , tho the liquor will still retain the orange colour . vii . we took common writing ink , and having let fall several drops of it upon a piece of white paper , so that when it grew dry in the air , some parts of the ink lay thick and some thinner upon the paper whereon it did spread it self , we put a few drops of strong spirit of salt , some on one part of the black'd paper , and some ( or perhaps a small drop ) on another , and observ'd , as we expected , that in these places , where the spirit had been put , or to which it reach'd , the blackness was quite destroyed , and succeeded by an unpleasant kind of colour that seem'd for the most part to participate of yellow and blew , neither of them good in its kind . viii . if in spirit of salt , you dissolve filings of steel , and slowly evaporate the filtrated solution , it will shoot into a kind of vitriolum martis that will be green as well as that which chymists vulgarly make with oyl of vitriol . and to add , that on this occasion , if you take these chrystals made with spirit of salt , and when they are dry , keep them in a crucible , you will find that even a moderate fire if duly apply'd , will make them in a short time exchange their green colour for a red , like that of the finer sort of crocus martis , as indeed this operation makes them referable to that sort of medicines . ix . we took some mercury precipitated , per se ( that is , by the sole action of the fire , without any saline additaments ) and tho crude mercury is not as far as i have tryed , soluble in our english spirit of salt ; yet this red precipitate ( which is suppos'd to be meer mercury ) with its own sulphur extraverted , did readily enough dissolve in that liquor , and if i very much misremember not , did not at all impart its own colour to it : and i also found that red-lead or minium being boyl'd a while in good spirit of salt , the redness did totally disappear . so that the same agent that produces redness in divers bodies , did in those two , i have been mentioning , more than change it , since it quite abolished it . of which also , i can give you an easier instance , by observing that the reddest coral being dissolv'd in our menstruum , the redness vanishes , and the solutition appears colourless . x. take filings of copper , ( the smallest are the fittest for this experiment ) , and having poured on them good spirit of salt till it swim , about two fingers breadth over them ; keep the vial in a pretty strong heat ( in a sand furnace ) till you perceive the menstruum has dissolv'd a competent part of the metal : then warily take out the vial , and holding it between your eye and the light , you will perceive the solution of copper to be not like that of steel formerly mentioned , of a green colour , but of a dark and troubled one , oftentimes inclining to a deep , but muddy red. xi . but if you pour this solution into a wide-mouth glass , and let it stand for a competent time , ( which sometimes amounts but to a few hours , and sometimes to very many ) the expos'd liquor will appear of a green , much finer than that of the chrystals of mars . xii . take filtrated and limpid solution of silver , or of mercury made in aqua fortis , and drop upon it some spirit of salt , by which you shall find the clear liquor turn'd white as milk , which after a while will let fall a precipitate of the same colour . xiii . and if instead of a solution of silver or quick-silver , you take a red solution or tincture of benjamin , or of the resinous part of jallap root , or you 'le also have upon the affusion of spirit of salt , a white liquor and a precipitate of the same colour . xiv . being desirous to produce two differingcolours at once by the same affusion of spirit of salt , i infused some dryed red rose leaves in fair water , till it had acquired a deep colour from them . to this infusion , pour'd off warily , that it might be clear , i added a considerable proportion of the sweet liquor , made by digesting spirit of vinegar upon red lead , by which i knew 't would be turn'd of a blewish green. upon this almost opacous liquor , i pour'd spirit of salt , which as i expected , precipitated the lead that had been dissolv'd in the sweet liquor , into a very white powder , and gave the remaining liquor , well impregnated with particles of the rose leaves , a very fine and durable scarlet colour . to which experiment i shall add on this occasion , that if it had been well made , you may barely by shaking very well together and confounding the white powder with the red liquor , make a carnation colour , which ( when 't is made as it should be ) appear'd very fine and lovely whilst it lasted , for in no long time the two substances that compos'd it , would by degrees separate , and re-appear each of them in its former place and colour . xv. we took some spirit of salt , that having lain long upon fylings of copper , had lost the muddy tincture it had first acquired by being almost boil'd upon them . this liquor , i say , that look'd like common water , we pour'd into a small , but wide-mouth'd christal-glass , about half an hour after in the morning , and leaving it in a window , it appear'd after minutes to have there acquir'd a colour , much like that of a german amethist , and seem'd to have no tendency to greenness . but being detain'd by the visit of a virtuoso till eleven a clock , i could not see what happen'd in the mean time : but then as he was going away , i invited him to see the liquor , which he ( not knowing what it was ) told me it look'd of a grass-green colour , wherein tho i were not altogether of his mind , yet in a short time after , it did to me also appear of a lovely green ; in its passage to which it had in all been expos'd about hours and a half xvi . precipitate a strong solution of sublimate , ( made in fair water ) with a s . q. ( and no more ) of oyl of tartar per deliquium . put the liquor and powder into a filter of cap-paper , and when the water is run thorow , there will remain in the filter the precipitate , which is to be slowly and well dry'd . then take it out of the filter , in the form of a gross powder , and having put it into a clear glass , let fall on it warily some drops of pretty strong spirit of salt , and ( if the experiment succeeds with you as it did with me ) during the conflict that will be made , the little lumps of the precipitate will lose all their former brick-dust colour , and turn white , tho afterwards they will appear dissolv'd into a transparent liquor , wherein the orange colour is quite abolish'd . xvii . having calcin'd copper without any additament , save fire and water ( by the way we elsewhere mention ) we took an arbitrary quantity of it , and having pour'd on it about or times the quantity of good spirit of salt , we obtain'd ( what we look'd for ) both a muddy , but manifestly reddish liquor , and ( somewhat to the surprize of the persons i had a mind to satisfy ) a white powder , whose quantity bore a considerable proportion to the part that was dissolv'd , ( but whose qualities belong not to this place ) in which part its self , ( to add that upon the by ) by the affusion of common water , and the action of the air , we afterwards produc'd more than one change of colour . xviii . we sometimes for curiosity sake took a quantity , not exceeding a spoonful , of the dark brown or somewhat reddish solution of ♀ , mention'd in the foregoing experiment , and having put it into a cylindrical vial , that the change of colour may appear the better , we pour'd on it or spoonfuls of totally ardent vinous spirit , and giving the glass a shake to mingle them , we presently had ( as soon as the mixture became clear ) a lovely green liquor , which when 't was well setled , was very fair , and lookt almost as if it were a liquid emerald . xix . we took some green taffatee ribband , and having moisten'd one part of it , that was not great , twice or thrice with good spirit of salt , we suffer'd it to dry of its self ; which it did in a short time , and then we found as we expected , that the wetted part was no longer of a green , but chang'd to a blew colour . but the same spirit , ( to add that upon the by ) presently turn'd that part of a piece of black ribband , upon which we put or drops of it to a colour not unlike that which they call fueille morte , or , a fading leaf . xx. 't is usual in paper-shops , and in divers other places , to meet with pamphlets and other thin books that are covered with papers that look sometimes of a greenish blew colour , bordering upon purple , and sometimes upon that of violets . some of the deeper colour'd papers of this sort , i have several times to gratify some curious persons , especially of the sex , held in my left hand , and with the other lightly and nimbly toucht them here and there with the end of a feather ( cut off from the rest of the quill ) dipt in spirit of salt , which almost in the twinkling of an eye , dy'd the toucht parts of the paper with a lovely red , that would sometimes continue very vivid for a good while , and be manifest at the end of divers weeks , if not months . and if instead of the forementioned quil , i took into my right hand ( a brush , or ) somewhat that was fit to sprinkle with , and having dipt it in the saline spirit , made many drops at once fall upon the paper , 't was pleasant enough to behold how suddenly and prettily it would be speckled . xxi . vve took antimony well powder'd , and pour'd on it or times its weight of good spirit of salt ; we caus'd it to be boil'd in this liquor , ( and that in a glass vessel ) wherein a part of it was dissolv'd , and taken up into the menstruum ; where the antimony quite lost its blackness . and this thus impregnated spirit of salt , being dropt into fair vvater , the black mineral subsided immediately , in the form of a very white powder or precipitate . to these i might add other changes of colours , that i have made , by the help of spirit of salt. but these being not of so quick and easy tryal , ( especially because some of them require skill in chymistry ) i thought it not fit to annex them ; supposing that those already deliver'd , amounting to above four pentades , may suffice for the purpose declar'd at the begining of this paper . and also to afford us this reflection , that it may not be amiss , if physicians , chymists , and others that are wont to compound drugs , or other ingredients ; would be less forward than they usually are , to mingle , not to say to jumble , several of them together , either unnecessary , or without due regard to the friendly and incongruous qualities ( in reference to one another ) that the separate ingredients may have . for most of us are but too lyable to be mistaken , when we presume before-hand , what changes the coalition , or other associations of differing bodies may produce ; especially if they be either saline , or plentifully partakers of a saline nature ; since experience frequently shews , that by the action and reaction that are consequent upon untry'd ways of composition , there emerge in the mixture new consistences and other qualities or accidents , that were not look'd for , when the ingredients 't is compounded of , were put together . and tho it may sometimes happen luckily enough , that these emergent qualities , whether of drugs , or other comparatively simple bodies , may prove advantagious ; yet this may well be look'd upon but as a lucky chance ; and hinders not , but that one may justly fear that ordinarily the newly produc'd quality of a medicine , may prove to be either worse than was expected , or at least other than was design'd , and consequently less fit for the physicians or the artists determinate purpose . chap. iv. an advertisement touching those passages that in this book relate to the art of medicine . the favourable reception the publick was pleas'd to give two editions set forth in one year of the usefulness of experimental philosophy , having encourag'd the stationer to solicite me for a new impression , i was on the same ground invited to think of making additions to divers parts of that treatise ; but afterwards observing that notwithstanding the thanks and acknowledgments i had the good fortune to receive from several physicians ( some of them of great reputation , and perhaps by that only known to me ) yet others were not well pleas'd that a person not of their profession should offer to meddle with it , tho with a design of advancing it : i , whose condition exempted me from taking upon me their calling , and who consequently must want many opportunities that others injoy'd of making observations about the phaenomena of diseases and of medicines , suffer'd my self without much violence to be diverted to other studies more suitable to my inclinations , as well as to my condition , and accordingly i laid aside the papers i had written in reference to the physicians art , nor were it easy , or perhaps possible for me to retrieve them , after they have lain so many years dispers'd and neglected , by which means perchance divers of them have been lost . but all this could not hinder me from being press'd to retrieve and communicate these scatter'd and dusty papers by the secretary of the royal society mr. h. oldenburgh : for as this gentleman has been almost every where wonderfully solicitous to preserve every thing from being lost , that may any way contribute to increase the stock of useful knowledg . so having got notice of these papers , and a sight of some of them , his partiality for me made him much over-value them , and perswaded him that a collection of them as incoherent and unfinisht as they were , might be of some use to the physicians art. and this seem'd the more hopeful , because natural philosophy being a science of far greater extent than physick , and supplying it , with many of its principles and theories ; 't is very possible that naturalists , tho not profest physicians , may propose some such comprehensive notions and methods , as may awaken and inlarge the minds of them that are so , and at least afford some useful hints to considering and ingenious men. and in effect divers physicians , as well as many patients , have been pleas'd to declare ( some in print , and some other ways ) that sometimes they found not useless assistances from some of those papers , wherein i occasionally touch'd on medicinal things . such motives as these made mr. oldenburg so earnest to procure the scatter'd fragments , that i might have yet remaining , about medicinal affairs , that tho for the reasons mention'd above , i could not think it fit to make a collection of papers so unlike in their subjects , so disproportionate in their bulk , and so unfinish'd and imperfect on divers scores ; yet thus far i was content to comply with his desires , that when these trifles came to hand , i would now and then insert them among my experimenta & observationes physicoe . ( medicine being a part , or an application of natural philosophy ) especially if there were any great affinity between the paper i lighted on , and the subject i was then treating of : knowing well that mr. oldenburg , and perhaps some others too , had rather i should impart them at all adventures , than suppress what they judg'd might be useful ; and that 't was better to run the hazard of having them slighted , than lost . this advertisement i thought fit to give in this place , once for all , that when hereafter there shall occur any thing among these experimenta & observationes physicae , that directly relates to the physician 's art , you may not think it strange , remembring upon what account i ventur'd to meddle with things of that nature , and also that you may readily understand what i mean , when you meet with any particulars delivered , as thoughts or desiderata or wishes , tending to , or aiming at the improvement of medicine ; which how slight or superfluous soever they may be to experienc'd masters , to whom i did not presume to recommend them , i thought might probably be serviceable to a very ingenious , but yet young cultivator of that noble art , ( whose name , i conceal'd after the way of the curious of germany under that of trallianus , ) for whose use they were intended . the i. pentade . experiment i. a very tall and well set gentleman , aged about years , by a fall from his horse , had his skull broken in several places , and being a person of good estate , had several chirurgeons to attend him in the course of his sickness ; during which he was divers times trepan'd , and had several pieces of his skull taken off , which left great chasms ( that i have seen and felt ) between the remaining parts . within about three days after his fall , this knight ( for so he now is ) was taken with a dead palsey on his right side , which did not equally affect his arm and his leg : the use of the latter being somtimes suddenly restor'd to him in some measure , and ( tho seldom ) after a while almost as suddenly lost : but his arm and head were constantly paralytical , being wholly depriv'd of motion ; and having so little sense , that it would sometimes lye under his body without his feeling it . but if his hand were prick't with a pin , he could take notice of it . this palsey continu'd during almost the whole time of the cure , which lasted or weeks . and when the chirurgeons were going to close up his head , as having no more to do ; one of them who was an ingenious man , and tenant to this gentleman , oppos'd all the rest , alledging , that , if they did no more , the gentleman would lead an useless and very melancholy life ; and that he was confident , the palsey was some way or other occasion'd by the fall , which had left somthing in the head that they had not yet discover'd . and the knight himself agreeing to this man's motion , his head was further laid open ; and at length , under a piece of proud flesh , they found , with much ado , a splinter , or rather flake , of a bone , that bore hard upon the dura mater , and was not pull'd out without a great hemorrhage , and such a stretch of the parts , as made the patient think his brain it self was tearing out . but this mischief was soon remedy'd , and his hurts securely heal'd up ; and he is now a strong healthy man , and finds no inconvenience by having so broad and various a callus instead of the skull ; save that he is a little obnoxious to take cold in his head. but the memorable circumstances , for whose sake i mention this narrative , were these : when i ask'd him how big the bone was , that was last taken out ? he told me , that it was less than half the nail of one of his fingers ( not his thumb ) and that it was almost as thin , being in size and shape like the scale of a fish : but that it did not in his head lye flat , but bore hard upon the dura mater . when i ask'd him how long after it was taken out , he began to feel some relief , as to his paralytic distemper ? he reply'd , that in less than five hours he found himself , to his great joy , able to move his little finger ; and ( tho this happen'd in the evening ) he was the next morning able to move all his fingers , and within or days after to lift up his arm : by which it seem'd manifest , that so little a body as the splinter lately mention'd , produc'd in so robust a person , a palsey of the whole side it lay on . for when i particularly ask't him , whether , after the taking away of the proud flesh that encompass'd the little bone , he did not find , if he found none before , some relief as to his palsey ? he answer'd , that he found none at all , till the bone had been pull'd out , which was not till a good while after the chirurgeon had been by degrees eating off the proud flesh that , grew about it . but there was in this case another phoenomenon that i thought little less considerable than the former . for , remembring the important controversie , that is agitated among modern physicians and anatomists , about nutrition by the nerves , and having thereupon ask'd this knight , whether he did not find an atrophy in the limbs of his body that were affected ? he told me , that when he began to be paralytic on that side , it by degrees much wasted , and the paralytic leg was very much extenuated : but the arm and hand much more , seeming nothing but a system of bones , with the skin pasted on them . and when i further ask'd , if upon the removal of the bony splinter above-mentioned , the atrophy of the parts did not also begin to lessen ; he answered affirmatively , and told me , that in no very long time his leg and arm recover'd their wonted dimensions ; and in effect i ( some days since ) saw the restor'd arm well plump'd up with musculous flesh , tho the weather were exceeding cold. and he further told me , that he found no difference between the limbs that had been paralytic , and the others , except that they would grow sooner and more sensibly cold in sharp or frosty weather . this gentleman answer'd me , to add that upon the by , that , during the course of his cure , he was very frequently ( almost every second day ) let blood ; that he wanted not appetite to his meat ; that for the most part he slept indifferent well ; and , which was more remarkable , upon so great a hurt of the head he did not vomit , not had afterwards any convulsions . ii. among other instances i have met with , that shew the great power which sudden passions of the mind may have upon the body , i remember that a woman of middle age , complain'd sadly to me of the mischief , a fright had done her ; for she related to me , that having taken along with her to a meadow by a river-side , a little boy that she was dotingly fond of , whilst she was busie about the work she came thither for , the child stole away from her , and went along the bank , to delight himself with the view of the stream ; but being heedless , it seems by circumstances , that he set his foot upon some piece of ground that the water had made hollow ; upon which account , the earth failing under the weight of the boy 's body pressing it , that , and he fell together into the river : in the mean time the poor mother casually missing her child , hastily cast her eyes towards the brink of the river , and not being able to see him there , she presently concluded him to be drown'd , and was struck with so much horrour upon the sudden accident that tore from her a favorite son , that among other mischiefs , she fell into a dead palsy of her right arm and hand , which continu'd with her in spight of what she had done to remove it , till the time she complain'd of it to me , who had not opportunity to know what became of her afterwards . iii. on the other side , to show that violent passions , and even frights may sometimes , tho very seldom , do good , as well as harm ; i shall here add a relation that was circumstantially made me by the learned person himself , to whom the accident happen'd . i familiarly knew a gentleman that liv'd to be an eminent virtuoso , and to oblige many by his useful writings , who when he was a youth , fell into a violent and obstinate sciatica , which continu'd with him so long , that it left him little hope of recovery ; but the devotion of this young man's friends invited them to make him be carry'd , since he could not go , to church upon sundays ; and there it happen'd , that the town being a frontier garrison , the guards were so negligent , that there was occasion given to a very hot alarum , that the enemy was got into the town , and was advancing towards the church to massacre all that were in it . this so amaz'd and terrifi'd the people , that in very great and disorderly hast , they all ran out of the church , and left my relator in his pew upon a seat that they plac'd him , and whence he could not remove without help : but he being no less frighted than the rest , as they forgot him , he forgot his disease , and made a shift to hamper off the pew , and follow those that fled ; but it quickly appearing , that the alarum had been a false one , his friends began to think in what a condition they had left him , and hasten'd back to help him out of the pew , which whilst they were going to do , they , to their great surprise found him in the way upon his feet , and walking as freely as other men. and when he told me this story , he was above forty years elder than when he was thus strangely rescu'd , and in all that time , never had one fit of the sciatica . advertisement . 't is easy to be observ'd , that of the two kinds into which chymists may be conveniently enough sorted ; the number is greater of those that are not profest physicians , than of those that are : and yet several of the former sort are led by their more free curiosity , or their particular designes , to allow a large scope to their tryals ; and so in their experiments upon various bodies , to operate upon some of those that may be reduc'd ( either directly , or by sit applications ) to the materia medica , and afford uncommon preparations : which tho design'd for other purposes , may by a skilful physician , with a light variation , and perhaps without any , be made to afford good medicines : and therefore i think it may be no inconsiderable service to the publick , if by the leave and assistance of the authors , divers chymical experiments that are not directly useful to their immediate purpose , were not , ( as is usual ) thrown away , but put into the hands of some sagacious physician . upon these grounds , i thought my self little less than oblig'd , to set apart now and then an experiment that contain'd some uncommon preparation , which seem'd applicable to medicine ; and to try whether , tho , being in the country or in some other inconvenient circumstances , i had not opportunity to prove it my self , the notice given of it , might not happen to be of use to a skilful physician . i shall therefore partly in this chapter , and partly ( if god permit ) in some following chapters and other writings , tender to such a one , some few of the experiments of this sort , that i lately lighted on among my adversaria , and that seem'd not uncapable to be made of some service to the physician 's art. of the good and bad effects of these , i shall be glad to be inform'd , that they may be either us'd more freely and improv'd , or corrected and quite laid aside ; and i desire that this short preamble may serve for a general one to all the other design'd chymical medicins that i shall venture to propose hereafter . a design'd chymical medicine . iv. i know how much men are prejudic'd in some whole countries , against vomitive medicines : and i remember we have had here in london a physician of great fame and practice , that would turn over a patient to another doctor , if the case were such that the patient would needs make use of emeticks . and i readily acknowledg that they are edg'd tools , that require a skilful hand , to imploy them without danger of doing more harm than good : but since experience shews that where the patient can bear them , and the disease requires them , they act more speedily and effectually than other evacuating medicines : and since the generality of our physicians , not excepting some that are justly reputed very cautious , do not scruple frequently to make use of the infusion of crocus metallorum , tho it do not seldom prove a remedy harsh enough ; i shall venture in compliance with some ingenious physicians , and others that have often made use of a medicine , that goes under the name of my emetick drops , to communicate the preparation of them ; without pressing the use any otherwise than by confessing that divers practitioners of physick of differing sentiments , agree in assuring me , that they have not yet found any emetick to work so effectually , nor with more ease and safety , than this liquor ; which some of them prefer by much to other antimonial vomits ; and especially to the infusion of crocus metallorum . in preparing my vomitive liquor , i have not always imploy'd the same proportion of the ingredients 't is made of , nor did i find it necessary to be nice in that matter . but the proportion i somewhat prefer , is to take two parts of well chosen and finely powder'd antimony , and on these to pour three parts of the menstruum , viz. sp. ; which ought to be rather moderately strong , than too much rectified . these are to be distill'd together in a glass retort fitted with a receiver not very small , till there come over a great part of the menstruum , which will usually towards the close be accompany'd with red flores , ( some times copious enough ) which being separated by filtration through cap-paper , the clear transmitted liquor is to be put into a glass , not newly wash'd , but dry on the inside , and to be kept close stopt from all intercourse with the air. the dose is usually to a man or woman , especially at the first time , from or , to or drops : but i know an ingenious physician that gives to or , or a few more drops , if the case be urgent ; and by that means he told me , that with a small button-bottle , that i chanc'd to give him a little before , he did in or hours rescue three gentlemen , that by a bad surfet with very bad circumstances , were suddenly brought into great danger of speedy death , and carry'd to a neighbouring tavern , as being too ill to be carry'd home . the vehicle may be a spoonful or two of wine , or black-cherry water , or ( which divers persons chuse rather ) of spring-water , drinking up the liquor immediately after , because there will some precipitation be made ; and then taking or spoonfuls of the same vehicle to wash it down . it usually begins to work early , and does it without causing near so much straining as vulgar emeticks , and yet makes copious evacuations ; and sometimes so eradicative of the morbifick matter , that the physician lately mention'd , who cur'd the three gentlemen , having a poor patient who had conflicted for above three years with an ague in several types , but most commonly quartanary , perfectly cur'd him with two doses of these drops , and a julap made chiefly of the distill'd water of a common vitriolick mineral . and this cure seem'd therefore to me , when the physician gave me an account of the drops he had from me , the more considerable , because the patient had made use of great variety of remedies ; and particularly he devour'd great store of the jesuits bark , or cortex peruvianus , ( perhaps because it was not well condition'd , or skilfulfully administer'd ) which sometimes alter'd the type of his ague , turning it to a single or a double tertian , and sometimes kept off the fits for a while , when 't was a quartane , but never cur'd him quite ; and left him in a deplorable estate , wherein the emetick drops found him . tho i sent this medicine to several patients , in whom , thanks be to god , it succeeded more than ordinarily well , yet i durst not venture to give it to children , or to very young persons ; but having gratifi'd an ingenious surgeon of good practice , with a stock of it , the tryals he made upon divers persons , with great success on other patients , imbolden'd him to give it to boys and girls , and afterwards even to several children , whereof he gave me a good account , only he discreetly took care to proportion his doses to the age and strength of his patients , and not to give the whole dose at once , but divide it into or parts , that if the first should work within half an hour or less , the second should not be given , or lessen'd in quantity . and if neither the second did work within about an hour , he added the third . and by this cautious method , he assur'd me that he had suddenly reliev'd several children in bad cases , and found not any mischief or danger ensue upon the administration of it . but children being tender creatures , this is to be further and cautiously try'd . postscript . having had occasion to keep by me some vials furnish'd with the emetick drops , longer than i thought i should need to do so : i observ'd that in tract of time , there , began to subside a white powder , wherein a good part of the emetick faculty of the medicine may be suppos'd to reside ; therefore 't will be best either to imploy the liquor in no long time after 't is made , or if one has not leisure or conveniency to do so , to shake the vial well ( that the powder may be rais'd and we 'l dispers'd through it ) just before it be administer'd . a design'd chymical medicine . there are many that having a high esteem for chalybeate waters , such as those of the spaw and tunbridg , which yet in many places are not to be had at all , and in few to be had well condition'd , are very solicitous to find succedaneums to them . to gratify some ingenious persons of this sort ( and improve a casual hint taken from a book of a somewhat like preparation propo●●ded for another purpose ) i remember , i employ'd a way of aemulating such waters that answer'd the outward phaenomena of colour and taste , and seem by the paucity and harmlesness of their ingredients like to be innocent medicines ; i had no opportunity to make tryal of them in physick , but finding that some inquisitive cultivaters of that art , valu'd them more than i did , i committed the experiment to paper , and now suffer it to come abroad , that it may be try'd by physicians , and either rejected or made use of , as success shall direct . the experiment as i made it , was this . we took one part of very good fylings of ♂ ; and ten parts of good distill'd vinegar . these we put into a bolt-head , and shop'd it well , and then in a mild heat of sand we digested them for about two days , and afterwards augmented the heat till the liquor appear'd of a deep orange colour , but yet transparent . part of this tincture we pour'd off , and kept well stop'd by its self , because tho by a longer digestion and a greater heat , we obtain'd a very red tincture , yet we did not so much value it , because when the menstruum is over impregnated , the metal usually precipitates , and the fine colour is destroy'd . of the first reserv'd tincture , we let fall drops into ℥ viiiss , ( ℥ ss ) of clear common water , whose colour was not thereby sensibly alter'd ; and the vial containing this mixture being well shaken , that the tincture might diffuse it self the more thorowly , we kept it carefully stop'd for use , as being our factitious or counterfeit spaw . a spoonful or somewhat more of this , with about a quarter of a grain , or less , of good fresh powder of gauls , would presently afford a purplish tincture , like that of natural springs impregnated with mars , such as the water of the german spaw , or of tunbridg in kent ; if ones mouth were wash'd with it , 't was found to have like those natural chalybeat waters , a manifestly faeruginous tast . n. b. these artificial acidulae are to be administer'd in no long time after they are made ; for experience has inform'd me , that ( at least sometimes ) when i kept them too long , within not many days after they were made , they would lose much , if not most of their briskness and force . and i sometimes perceive that there would subside to the bottom a certain red or reddish substance , as it were oker , which was a token of the degeneracy of the liquor ; and some such thing i have observ'd in some natural chalybeat waters too long or negligently kept . but our acidulae may be so soon and so cheaply made freshly , that the above mention'd inconveniency will scarce to the skilful seem considerable . the ii. pentade . experiment ii. because it may be on some occasions of use to a physician , to have ways of discovering the adulterateness of bezoar stone , which for its dearness is often counterfeited , and not easily discern'd to be so by the common ways of exploring , which use to be uncertain enough ; it may not be amiss to communicate a new way of tryal , which 't is unlike that impostors have dream'd of , or if they should know it , can easily elude . and this i am the rather willing to do , because the propos'd way may afford an useful hint to the sagacious inquirers into the nature , and some of the preparations that may be made , of the bezoar stone ; which tho it be a drug too much magnify'd by some physicians , especially those that depend on it , against the true plague ; yet a physician of great experience , and rather a severe , than any ways a partial judg of it , allows it to be an excellent remedy even in malignant and ill-condition'd fevers , at least if they be not truly pestilential . one of the ways i imploy'd , in treating the bezoar stone , may be easily gather'd from the ensuing transcript of one of my register'd experiments . we took or grains of choice oriental bezoar stone reduc'd to powder , and in a bolt-glass pour'd on it . ʒvi of good spirit of niter , as well to try whether this liquor would prove a fit menstruum for : this stone , as we found it to be for the calculus humanus , as for other purposes . and tho this affusion being purposely made in the cold , the liquor did not seem at first to work on the stone ; yet soon after it fell violently upon it , and dissolv'd the greater part of it , not without noise and a notable effervescence . the solution was almost red , and the glass being put in a digestive furnace , the whole powder was not only dissolv'd , but being left a night or two in a north window , it afforded divers saline concretions , much larger than could well have been expected from so small a quantity of matter ; and these crystals , whilst they were yet in the glass , might easily be taken for crystals of salt-peter , so great was their resemblance . to manifest how much the faculties of loosening and binding , are relative things , and depend upon the disposition of the body to be wrought upon , and so upon the congruity betwixt the agent , and the patient , i know an ingenious gentlewoman , on whom cinnamon , which generally is a considerable astringent and stomachick medicine , has a quite contrary operation , and that in a strange degree , insomuch that having found by or accidental tryals , that a very little cinnamon seem'd to disorder her stomach and prove laxative , she resolv'd once to satisfy her self , whether those discomposures came by chance , or no ; and having strew'd some powder'd cinnamon upon a tost , she was going to put into her ale , upon eating the tost she was copiously purg'd for two days together , and that with such violence , that it put her into convulsion fits , and a kind of spasmus cynicus , which she could never be perfectly freed from , being troubled with from time to time for . years , as was the other day averr'd to me , and divers others that know her , by her husband who is himself a learned man and a profest physician . a prosperous physician , to whom i had recommended some things relating to his profession whilst he practis'd it with success in the capital city of ireland , where at that time there rag'd a new and violent fever , whereof multitudes dy'd , very few patients recovering of it , happily lighted on a method that prov'd , through god's blessing , very prosperous . this doctor returning into ireland sometimes before , having been desir'd by me to send me an account of some things relating to natural philosophy and physick that i nam'd to him , wrought to me in answer to some of my enquiries a letter , out of which i thought fit to make this extract , because i know not but that it may give good hints towards the cure of some other ill-condition'd fevers . dublin , feb. . . i have imployed ens veneris for the removal of a subsultus tendinum , in a person dangerously sick of a febris petechialis ( a discase fatal to very many here for these or months ) and found that it answer'd my hopes in or hours after i gave it in conserve of borrage flowers . i have , since i came from england , thought of a method of curing the aforesaid fever , which has not once fail'd me , tho i made of it for or several persons , many of which would certainly dye , if treated after the usual manner in this case . if i should tell you from what observations and reasonings i came to alter the method of cure , i should be very tedious . i shall therefore at present wave that , and proceed to tell you , that when first i come to any sick of this disease , if i find costive ( as generally they are ) i prescribe a glister , and after that an episplastick plaister or inches broad , and or inches long , to be apply'd between the shoulders ; the blister being well rais'd , i order to be dress'd carefully , stripping off the cuticula . this continues running till the fever is gone off ; which is most commonly in or days , if they have not kept up too long with it , and then we cannot certainly foretel the time of the fever's declination ; for the whole time till the going off of the fever , i prescribe emulsions of aq. aronis , card. bened. citrij totius & syr. granatorum cum aceto ; i allow of orange and butter-milk possets , of roasted apples , flummery , or any other light and cooling thing they call for . by this method i keep the genus nervosum and brain from being affected , and consequently secure my patients ; for as many as i have ever known of them dye , that were troubled with this disease , dy'd of a disorder of those parts . i do not defer the blistering plaisters , as others do , till i find my patients delirous , lethargick , convulsive , or otherwise affected in their heads and nerves , finding by the experience of others that then they most commonly prove ineffectual , because of some morbifick matters being too deeply lodg'd in these parts . i do not prescribe , except upon some extraordinary occasions , any volatile salts or spirits , or any thing too apt to quicken the already over-brisk circulation of the blood , having experimentally learn'd that by these often us'd , the brain and nerves become sooner than ordinary affected , for as much as they deeply insinuate themselves , and drive with them some morbifick matter into the brain and nerves . i find bleeding bad , being generally fatal . if i doubt of the recovery of any of my patients sick of this disease , 't is only when i find that they have been let blood , or lain for or days before i come to them ; tho i have brought through it , even persons in those circumstances . a design'd chymical medicine . i shall not , because i need not , discourse of the medicinal vertues of steel in a city where many learned physicians do so much esteem and imploy chalybeate medicines as they do in london , and therefore i shall content my self at this time to offer you a couple of preparations of steel that possibly you have not met with or thought of . . considering that most of the ways made use of by chymists to prepare steel , tend by dividing it into very minute parts , to make it more lyable to be wrought on by the liquors of the stomach , and some other parts of the body , and that the generality of these chalybeate preparations are wont to be made only with acids , whether manifest , as oyl of vitriol , spirit of vinegar , &c. or occult , as brimstone , which tho insipid in its natural state , when it comes to be melted , discloses its hidden salt , and works on ♂ by a sharp acidity ; considering this , i say , and that men have confin'd themselves to acids in working on steel , because they suppos'd instruments of that kind were necessary to dissolve that metal , i thought it might do you , and some ingenious men of your profession , some little service , if i propos'd to you a way of opening the body of steel , that tho i gave a hint of it divers years ago , is , for ought i know , yet unpractis'd . we took then several ounces of highly rectify'd spirit of fermented ( or putrify'd ) urine made per se , and consequently without quick-lime , and pour'd it upon as much filings of steel freshly made , to be sure , not to have any rusty ones , as we guest , would at least suffice to satiate it fully . these we put in a moderately warm place , where the menstruum wrought on the metal for divers hour together , and dissolv'd a considerable part of it . this solution we set to filter , and found it of a taste considerably strong , but very different from any of the chalybeat preparations , we remembered , that were seen made with acids . the liquor being kept in a stopt viol for some days near a window , did in the cold let fall by degrees a considerable quantity of powder of a deep green colour , which surpriz'd some virtuosi , to whom i shew'd it , especially because the liquor it self was not of that colour ; tho at least the superficial part of what remain'd ( in plenty ) in the filter , did also in the air acquire a green colour . but tho our solution pour'd off from the subsided powder , was warily and slowly evaporated , yet we did not find it would well crystallize what use may be made in physick , of preparations of this kind , i leave to you , whose profession as well as curiosity will ingage you to consider . i do not presume to tell you , but in general it seems that steel prepar'd with volatile spirits of the animal kingdom that are wont to be friendly to nature , and are very contrary to acids , may have new qualities very differing from those of steel prepar'd with acids , and may be more safe in some cases and to some patients . with what other volatile menstruums i have dissolv'd mars , and what phaenomena some tryals i made with that metal open'd by such salts , you may command an account of , if you think it worth desiring . a design'd chymical medicine . another experiment that i made on steel , was design'd to make as much of it volatile , as i could with a menstruum , not so corrosive or dangerous to the body as oyl of vitriol , or spirit of niter , which , especially the former , are imploy'd by divers chymists to make chalybeat preparations that yet are not volatile . the medicinal scope i had in my eye , for i had also a chymical one ( that belongs not to this place ) was to try if i could by it obtain any sulphur of mars , which the commendations that some , even of those chymists , whether adepti or not , whose authority i most regard , represent as an excellent medicine , especially in cases that require anodynes , and which the others , or the same speak of as a graduatory substance ( as to some metals ) or both : if you should ask me , why i did not make use of the common vitriolum martis , which is easy to be had in the shops of chymists ? i answer , that my design being to try whether or no i could obtain a sulphur , that might properly enough ( tho not in the utmost rigor ) we call sulphur of mars , that which is made the common way , would not answer my end , since tho i should be able from this vitriol to obtain a real sulphur ; yet i should not think it safe thence to conclude , that it came from the metal , and not from the menstruum ; because i have several times from oyl of vitriol it self , obtain'd no contemptible proportion of yellow and combustible sulphur . to which i add , that the acquisition of a metalline sulphur , tho it was not the only thing that i aim'd at in this preparation , for i presum'd , that at least i should make a very great comminution of the parts of steel , which is one of the main things aim'd at by the more rational physicians in the preparations of that metal . upon these and the like grounds , i pitcht upon good spirit of sea-salt as a menstruum , much fitter for my purpose than either oyl of vitriol or the acid part of sulphur ; and accordingly in a good many ounces of this menstruum , we dissolv'd as much as we easily could of choice filings of fine steel , and having filter'd the green solution , we very slowly evaporated it in a glass vessel , and took such care not to spoil the matter , that we had store of fine green crystals that were not very small , and lookt prettily ; most of these we put into a strong , but small retort , and by degrees of fire , and a strong one , for the last hours ; we obtain'd divers ounces of a liquor that came over in white fumes , like mists driven by the wind , and afforded a sulphureous smell : this liquor we rectify'd , and had a yellow ponderous spirit , that seem'd to be much more of kin to the spirit of sea-salt , than to the common oyl of vitriol ; especially since being mixt with aqua-fortis , it would , like spirit of salt , make it a menstruum , that would even in the cold dissolve gold in thin leaves . which last words i add , because having put into a little of it already made yellow , by having dissolv'd leaf-gold a very thin plate , but a pretty deal thicker than a leaf of hammer'd gold , the menstruum made it look all over white , almost like silver , which seem'd to argue , that this vitriolate menstruum differ'd from common spirit of salt. and however , it may be worth taking notice of by the by , that not only vitriols blue , as is well known to chymists , but that vitriols of one of those colours , and whereof the same metall is the basest , may differ much from one another on the score of the various , and to us perhaps , unknown menstruum that dissolves the metal , since our green vitriol yeilds liquors very different from common english vitriol of mars made with oyl of vitriol , tho all the three be green . which may give us some reason of the uncertainty , whereof vitriol is mainly imploy'd ; and 't is perhaps worth remarking , that tho we did not find the vitriol of mars made the common way , nor even roman vitriol to dissolve in a vinous spirit totally inflammable , yet it would easily enough dissolve our saline vitriol , ( if i may so call it ) which solution to hint that in transitu , you may perhaps see cause to imploy as a medicine in several cases , and particularly as a styptic in wounds , since its tast is very astringent , its parts very subti , and made fit by the vinous spirit , to prevent corruption ; especially in those clymates where chirurgeons complain . that they can scarce prevent the breeding of worms in wounds , unless they do betimes dress them with spir. of wine or brandy . but that which we chiefly aim'd at in this operation , was the dry part , of what was elevated by the force of the fire . this we found to be distinguishable , partly by its situation , and partly by more durable accidents , into three kinds of substance , whereof one was almost like a powder , which after the contact of air , did in a while come over to be of a yellow colour , almost like sulphur , but it was not indeed truly combustible sulphur . the other substance consisted of larger parts , and was of a deep colour , between read and brown. but the third , which seem'd the most copious of all , was made up of fine parts , larger than the former , of a deep reddish colour , and adorn'd with a fine gloss , like that of scales of fishes , that look'd very prettily . the caput mortuum was found to be of a texture that would have surpriz'd most men ; for a great part of it appeared to be turn'd into a talky substance , consisting of pretty broad and very thin plates , smooth and glossy , that lay upon , and against one another , like those that make up muscovia-glass , when the pieces are more thick than large . chap. v. containing experiments and observations solitary ; in two pentades . the i. pentade . experiment i. a notable comminution of gold into powder that will sink in water . to manifest into how great a multitude of corpuscles , gross and heavy enough to sink to the bottom even of a saline liquor in the form of precipitate or powder ; i thought of this expedient . we took a grain of refin'd gold , and having dissolv'd it without heat in a competent quantity of good aqua regia , we put to it by guess about two spoonfuls of water , and then by a thread we hung in the mixture a little bit of clean metaline body , and kept it suspended in the liquor for many hours ( or some few days . ) by this means we obtain'd , as we expected , a precipitate of a fine and deep colour , so copious and so light , that it was a long time before it would all settle at the bottom . then looking upon the remaining part of the suspended metaline body , we found it so very little less than when the whole was first put in , that the diminution of it was not judg'd to amount to near a grain . by which experiment it appear'd , that one grain of gold , not swiming in parts separately invisible , as 't is in solutions , but reduc'd to a manifest powder , seem'd to make a considerable quantity of precipitate at the bottom of the cylindrical vial , whose diameter was about an inch , that we kept it in . and this glass being a little shaken , the precipitate would rise like a mud , and be so thorowly disperst in the form of a powder , through the whole body of the liquor , and a greater quantity of water added to it , that at first it would seem opacous , and after some time , it would appear like a high and lovely purple solution . so that one grain of gold ( for the colour argu'd that there was some of that metal , in every corpuscle of the precipitate ) was reduc'd into as many grains of powder , as suffic'd to lodg themselves in all the particles of space great enough to be visible , that were contain'd in a mass of sixteen drachms ( is two ounces ) of water . experiment ii. a proof of the metalline nature of granates . i have else where endeavour'd to shew that divers , if not most , of the real vertues of some gems , ( for there are too many fabulous ones ascrib'd to them ) may in probability proceed from the particles of mineral juices , that were admitted whilst the matter was yet in solutis principiis , or at least soft , and afterwards coagulated with the lapidescent part of the stone . in confirmation of this conjecture , i shall now observe , that having , upon some grounds not necessary to be here mention'd , suspected that granates contain ( some of them ) besides some other metalline substances , divers corpuscles of a martial nature ; i made choice of some small ones , which by their deep and almost dark colour , ( to name no other signs ) i guess'd to contain somewhat of iron or steel ; and apply'd to them a pretty vigorous loadstone , which as i expected , readily took them up and to which they constantly stuck afterward , till i forcibly separated them from it . but tho i try'd this upon more parcels of garnets than one or two , yet i found that there was not many in one heap , that would easily adhere to the magnet . experiment iii. a gentleman eminent for his travels into eastern parts , and for his skill in jewels , told me , in confirmation of my opinion about the origine of gems from fluid materials ; that he had seen a white saphir that was a table-stone , as they speak , i. e. flat and not cut in facets , about the middle of which there was a cavity about the bigness of a large pins head , or small fitch , that contain'd in it a drop of liquor that it seems could not be coagulated into stone with the rest of the matter : which liquor , he said , was very easily discernible by its shifting places in the cavity , when the stone was put into differing postures . and when i ask't , whether there was no flaw or commissure in the stone , at which the liquor may be suspected to have got in ; he assur'd me that there was none , but that the cavity was every way encompast by the solid stone , and was about the thickness of three barly corns beneath the upper superficies of it . scholium . it may be here fit to give notice once for all , about the experiments that are in the following collections , styl'd solitary , that tho most of them are deliver'd nakedly as matters of fact , without any such introduction or subsequent reflection , as may be met with sometimes expressly , and oftner by intimation in divers others ; yet that it should not be thence infer'd , either those that are simply recited , were lighted on by chance , or made at all adventures , or that they are of no use , because for the most part there is not any expressly ascribed to them : for as they were not written without a particular occasion and scope too , so that many of them may be apply'd to good purposes , will , perchance , be found here and there in our other writings . and to make it probable in general , that most of them may not be useless , it may perhaps suffice that we refer to what we have elsewhere purposely discoursed , about the uses of experiments ( even ) to speculative philosophy . this may pass for a general scholium applicable to most of those experiments that are not attended with any particular scholium , nor any thing in the experiment or observation its self , that may easily by an attentive reader , be made to supply the place of a scholium . which last clause i add , to intimate , that besides my hast , another reason why so many scholium's , as may be expected in the following collection , will not be found in it , was , because the proemial part did , on several occasions , make it needless to subjoyn annotations . experiment iv. an ingenious and credible person ( mr. w. ) assur'd me , that in one of the fine gardens near genoa , that he delighted to visit , there was pond , which being made on the side of a hill , the wall next the bottom of the hill was so high , that men could not look over it into the pond , nor be at all seen over it by the fishes in the pond ; and yet he has several times observ'd these fishes to be call'd together by the gardiner , as he pleas'd , with a certain noise that the gardiner made to assemble them , tho neither he nor any man else could be discover'd by the fishes that readily obey'd their summons . this relation may be of use in the controversy , whether fishes hear under water . experiment v. upon occasion of what is elsewhere said of the production of vivid apparent colours by the breaking of the beams of light , on corpuscles extraordinary minute , tho solid ; i took a globe of rock chrystal , which being for a certain use saw'n in two by a cutter of gems , and having lookt upon the flat surfaces , observed to the sun beams , the little particles that ( notwithstanding their seeming smoothness in the shade ) asperated their surfaces , did so retract and reflect the light , as to make them exceed the vivid colours of the rain-bow , ( but in a somewhat interrupted manner ) sometimes on one part of the surface , sometimes on another , as the surface happen'd to be scituated in reference to the sun. and having caused a choice and fine grain'd touch-stone to be likewise saw'n asunder by the same artificer , to make two of it ; i observed upon the new surfaces made by this action , that to the touch smooth and polish'd , such vivid colours as i lately mention'd to be these surface , were put in to various position in reference to the sun and the eye ; so that notwithstanding the great transparency of the chrystal and great opacity of the touch-stone , their superficial corpuscles were found fit to exhibit ( in due positions ) the vivid colours we admire in the rain-bow . the ii pentade . experiment i. having for less than two hours borrow'd an oculus munai , whose colour was white , whose figure was round and plain convex , and whose diameter , i judg'd , to be about a third part of an inch ( rather less than more ) i put it into a very shallow glass vessel almost fill'd with fair water , and observ'd within one minute , or thereabout , with the minute-watch , that one part of the edg began to appear somewhat diaphanous , and the whole stone did by degrees lose its whiteness , appearing of a dark brownish colour : when this change had reach'd the whole surface , i look'd upon my watch , and found that the stone had lain nine minutes in the water ; out of which having taken it , i perceiv'd the body was grown semi-diaphanous , and the parts near the edg being less thick , appear'd to have lost much more of their former opacity than the innermost part had . then putting the stone presently into the water again , i let it lye there so long till the time efflux'd , since the begining of the experiment amounted just to half an hour . then taking it out , and wiping it , i found it was grown much more clear , since being held against the light , it look'd almost like yellow amber , but not quito so diaphanous . then i expos'd it to the contact of the air , in the scales of a very good ballance ( where it weigh'd four grains and about a quarter ) and left it for a quarter , or near half an hour , in that ballance to try if by the recess of any imbib'd aqueous moisture it would become lighter ; but want of time hindred me from compleating the experiment , but did not deter me from making another observation , which was , that within about a single minute of an hour , a portion of the stone near one part of the edg , was manifestly grown opacous and whitish , and within not many minutes after , the whole stone began to appear in a changing condition , but did not change in every part at once , nor did the alteration make an uniform progression ; but here one might successively discover divers white arches , or as 't were zones , that were parallel enough to one another , and being quite opacous , intercepted between them other little zones , which being yet semi-opacous , appear'd of a brown colour , and concurr'd to make the stone look like a very pretty agate , wherein the whiteness made a continued progress as long as the time permitted me to observe it : and the possessor assur'd me , that within an hour or or two it would be all of a cream white ( as he express'd himself ) which i thought the more credible , because i saw one part of it , that was pretty broad , to have obtain'd already a whiteness , little , if at all inferiour to that of ivory . experiment ii. remarkable observations about hurricanes . the late governour of the bermudas islands , ( very much subject to hurricanes ) in answer to my questions , about the presages of those hideous tempests , inform'd me , that these were of the principal forerunners . first , that the sea would manifestly swell at some distance from the shores , insomuch , that the fishermen would divers times make to land , and warn the inhabitants , upon the confidence of that presage , to provide against that dismal storm , tho the sea were then smooth enough . secondly , that the sea would beat with great noise against the shore , especially the rocks , tho there appear'd no manifest cause , as upon the account of the wind or tide , why it should do so . and this sign would sometimes not appear till many hours , or perhaps a full day after that foremention'd . and sometimes 't was observ'd , that the sea would now and then suddenly invade the shore , and gain further upon it than could be accounted for by the wind or tide , and then quickly ebb away beyond the usual low water-mark , and after return again with more fury , and fall back further than before . thirdly , that sometimes there would be perceiv'd an ungrateful smell in the air , before the hurricane began to blow . and fourthly and lastly , my relator affirm'd to me , both he and others had seen many bundles , as it were of long streaks of differing colours , some whitish , some reddish , and some blewish , or greenish , which by reason of their figure are usually call'd in those parts horse-tails : and these were seen in parts of the sky , where the air was troubled indeed , but yet no form'd clouds did appear to the eye . experiment . iii. a monstrous pearl . yesterday a curious person came to shew me a monstrous pearl , if i may so call it , because it was very irregularly shap'd , and of an enormous bigness . for tho it were so artificially set in gold , that by the help of a little of that metal fitly plac'd here and there , the whole jewel represented a lion ; yet i made shift to measure it exactly enough with a pair of calapar compasses , ( as they call those whose legs are made arch-wise ) and found the length to be just an inch and an half , and the greatest breadth ( where yet it was of a proportionate thickness ) to be / or / of an inch. the colour was orient enough , all but one dark spot , which by its size , figure , and situation , i guess'd to be the remains of that part ( whether like an umbilical cord or no ) whereby it was fasten'd to the naker or shell of the fish that produc'd it . experiment iv. an odd observation about the influence of the moon . i know an intelligent person , that having by a very dangerous fall , so broken his head , that divers large pieces of his skull were taken out , as i could easily perceive by the wide scars that still remain ; answer'd me , that for divers months that he lay under the chirurgeons hands , he constantly observ'd , that about full moon , there would be extraordinary prickings and shootings in the wounded parts of his head , as if the meninges were stretched or press'd against the rugged parts of the broken skull , and this with so much pain , as would for or nights hinder his sleep , of which at all other times of the moon he us'd to injoy a competency . and this gentleman added , that the chirurgeons , ( for he had or at once ) observ'd from month to month , as well as he , the operation of the full moon upon his head , informing him , that they then manifestly perceived an expansion or intumescence of his brain ; which appear'd not at all at the new moon ; ( for that i particularly ask'd ) nor was he then obnoxious to the foremention'd pricking pains . experiment . v. an uncommon experiment about heat and cold. to confirm what we have elsewhere deliver'd about the mechanical origine of heat and cold , we devis'd the following experiment : we took a small and hermetically seal'd thermoscope , whose stem was divided into parts , equal enough as to sense , by little specks of amel , that sharp liquors might not eat off or spoil the marks . the ball of this instrument we put into a slender cylindrical vessel , ( call'd in the shops a mustard glass ) and more than cover'd it with strong oyl of 🜖 , and left it there awhile to be reduc'd to the temper of the surrounding ▪ liquor . then we cast upon it by degrees , grosly powder'd , * which presently was wrought on furiously by the menstruum ; and by this conflict , was produc'd a seeming effervescence , with great noise and store of froth , which more than once was ready to run out of the vessel . but for all this seeming ebullition , the mixture instead of growing hot , did really grow colder and colder , as appear'd not only when the vessel was touch'd by the fingers on the outside , but by a surer mark , which was the descent of the colour'd spirit of wine . how much farther it would have descended , ( for the liquor was not near satiated with the 🜔 ) we were hinder'd from discovering by an unlucky accident , that broke the thermometer , and put an end to that first part of our experiment . but this was no hindrance to the second part , which for its novelty we mainly design'd . for when we pour'd this actually and considerably cold mixture into three or four times its weight ( by guess ) of as much common water , that was likewise actually cold ; this second mixture did , as i expected , immediately grow so hot , that i did not like to keep my finger for a minute or two upon the outside of the glass . an advertisement about the nature and scope of the chymical experiments contain'd in the following pentades . chap. v. containing two pentades of chymical experiments . before you enter upon the perusal of the following pentades , i think my self oblig'd to give you notice , that you will be deceiv'd if you expect to find them consist , either solely or mainly , of spagirical secrets , or difficult and elaborate processes . i do not indeed deny , that i am not altogether unfurnish'd with such as in probability , most readers would refer to experiments of that nature , and you may find divers of them scatter'd upon fit occasions , in several of my writings : but in the present tract , tho i have not forborn to mention here and there as many particulars of that sort , as i thought necessary to excite and maintain the curiosity , and sustain the attention of a reader that relishes nothing that is not season'd with somewhat that is not common ; yet in this treatise , wherein i aim'd not to appear a chymist , so much as to make my reader a naturalist ; it was more suitable to my design , tho not more conducive to my credit , that the following pentades ( which god permitting , may in tract of time , much increase in number ) should mainly consist of experiments , rather useful than specious ; my design being to contribute some sound materials towards the erection of a solid and useful natural philosophy . in making choice of which materials , i usually prefer those experiments that afford the more light to those that appear with the most luster , and those that are proper to increase the readers skill , to those that make an ostentation of the writers . on which ground it is , that , whatever i may do , where i purposely recommend chymistry , i make this small collection , consist mainly of simple and not intricate or elaborate experiments . those that are simple being not only more easy to be try'd , and if need be , reiterated without much trouble , or danger of erring ; but ( which i more regard ) more easy to be judg'd of , as to their causes , phenomena and effects , and consequently more fit to ground notions and reasonings upon : divers of which may probably in the applications that sagacious persons may make of them , prove to be of practical as well as theorical use . thus tho a wedg of gold and a diamond be , one more rich and finely colour'd , and the other more precious and sparkling than a piece of steel and a hint ; yet on many occasions the two latter are far more serviceable to mankind than the former : since not those that are more priz'd for themselves , but those that in comparison seem despicable , afford sparks , which do not only give light , but are fit to kindle fires , which both afford incomparably more light , and in the application are of excellent and necessary use in the kitchins of families , the forges of smiths of all sorts , the furnaces of myne-men , and the laboratories of chymists . the i. pentade . experiment i. to dissolve crude gold with dry bodies . because the generality of chymists make so great a matter of aurum potabile , tho they cannot deny , but that by their preparations it is not made irreducible ; and because also i am willing to grant , that even some preparations , that leave the metal reducible , may yet be of considerable use in physick ( the grounds of which opinion i elsewhere declare , and shall not here repeat ) i will in this place set down a process , which tho i do not overmuch value , serv'd me well enough on some occasions , to vye with those that much vaunted their particular ways ( as they thought them ) of making aurum potabile , i told them , i could make one in an hour or two's time without a furnace ; and that without any other distill'd liquor whatsoever than common spirit of of wine well dephlegm'd . this i did several times , after the following manner . i prepar'd a saline mixture consisting of one part of sal almonia● , two parts of roch allum , and four parts of pure nitre . this being well pulveriz'd and mingl'd , i rub'd diligently in a glass or marble mortar , with or parts in weight of the whole mixture of leaves of gold , such as apothecaries and book-binders use . then i put this into a small new crucible , and putting a few , and but a few , kindled coals round about it , and at a little distance from it , to neal the vessel ; i soon after approacht them , till the heat made the matter melt , and so with that gentle fire , i kept it in fusion , till it visibly emitted no more fumes but grew dry again . this sign appearing , i presently took it off from the fire , and whiles it was yet warm , dug it out , as clean as i could , and having seasonably pulveriz'd it , that it might not attract the moisture of the air ; i put upon it some highly rectify'd spirit of wine , which within an hour or less time , was enobled with a rich golden colour . and accordingly i found it to be a real solution of gold , by divers tryals that i purposely made , to evince it to be so . of this and some other less common preparations of ☉ more may be met with hereafter . experiment . ii. luna cornea by distillation . there was taken ℥ iii of well refin'd silver , thinly laminated , and six of common sublimate . this was put first into a retort , and the silver cut into small pieces , was put in after , that the matter lying uppermost might be penetrated by the ascending fumes : but the fire having not been made strong enough , the sublimate was elevated to the uppermost part of the retort , and left the silver scarce at all chang'd in the bottom of the glass . wherefore we put the same sublimate and metal into another retort , and administring a stronger fire , that the sublimate might be thorowly melted before it could flee away , we obtain'd no running mercury at all , but the greatest part of the sublimate was elevated in its usual form , leaving behind it the silver in a lump , which stuck hard to the bottom of the glass , and appear'd much alter'd . for besides that there was acquir'd ℥ i. in weight , many of the pieces of metal stuck together , and seem'd at least half melted , and were of a kind of horny and semi-diaphanous substance , which would readily enough melt almost like sealing-wax , when i held it to the flame of a candle , at which yet i could not perceive it manifestly to take fire . scholium . 't is here to be noted once for all , that in this and divers other chymical experiments , there is sometimes much more deliver'd than is necessary to make good the title , or the thing mainly intended . but 't was thought fit , not to dismember or mutilate the entire memoir as 't was register'd , because that of the other particulars some may be , tho indirectly , refer'd to the principal part , and others may be look't on as phaenomena , which may be of use at least to me , by keeping me from forgetting them , and probably tend to the main design of all these experiments , viz. to contribute to a natural history , which may respect practice , as well as theory . experiment . iii. mercury growing warm with silver . we took ʒii of animated ( or antimonial ) quicksilver , and put it into the palm of ones hand ; we put to it by degrees a dram and an half of powder of fine silver , made by precipitation with copper the ordinary way ( but with more than ordinary care ) . whilst this mixture was making with ones finger , he that held it in his hand , confess'd he found it grow sensibly warm ; and i , whose finger was considerably warm , could not with it perceive any coldness in the amalgame . this in a very short time became of a soft , and ( as to sense ) uniform consistence , and so soft that it was like almost melted butter , insomuch that we added half a dram more of the calx of silver , without rendring the amalgame at all too stif ; and perhaps we might have added the other half dram , without overcharging that penetrant mercury : in which case it had swallowed up full its own weight of silver ; so different it was from common mercury ; and when we left off , it had reduc'd into a very yeilding form , three quarters of its own weight of solid metal . this aaa we put into a small vyal , and stopt the glass with a cork , to observe whether the amalgame would harden without intercourse with the free air. next morning it appear'd to be concreted in the glass ; and the next morning after that , we broke the glass to take out the matter , which we found considerably hard , but brittle enough . experiment . iv. the durableness of the faculty of a certain prepar'd mercury to grow hot with gold. to convince those that treat the incalescense of prepar'd mercury and of gold , as a chymical chymera ; i sent in a conceal'd way to the royal society , some mercury laboriously prepar'd in my furnaces , whereof ℥ i. being put upon a due proportion of a calx of gold made by the common way , ( quartation ) they grew presently and very sensibly hot in the palm of ones hand . i shall now add , that to try whether this surprizing faculty of growing hot immediately upon gold , will continue any long time in the mercury ; i lately took some that i had ( for a certain purpose ) kept hermetically seal'd in a glass egg for divers years , ( if i mistake not , ten or twelve at least ) and having reiterated the foremention'd tryal with it ; first alone , and then in the presence of a cultivator of chymistry ; it presently grew hot with the ☉ in the palm of the hand . and having distill'd off the mercury , and try'd it again as well as some that was undistill'd , if i much misremember not , it did again heat with the gold. experiment . v. an uncommon way of operating upon ♁ . when chymists expose antimony , for instance , and divers other consistent , but not fixt bodies , to the action of the fire , they are wont to do it in vessels , either open , as when they make calx , or glass of antimony , or at least in vessels that are not so close : but that there is air included with the matter , as when they sublime it in glasses , or in earthen subliming pots ; and tho they regard not this included air , because usually there is not much of it in the vessel , yet it may have a not inconsiderable influence on the effects of the fires operation , not only as it contributes to the ascention and sustentation of dissipated parts of the mineral , but as it affords these corpuscles room to fly to and fro in it , and thereby make associations or coalitions and concretions that otherwise would not be produc'd . upon this account i guest that it may be , on divers occasions , a thing of use for discoveries , and perhaps too , for practice , to imploy a method , that the body expos'd to the action of the fire , may be kept from the contact of the air , at least as to any sensible portions of it , and being as it were included in bodies almost equivalent to solids ; and one may suppress the free emission and ascent of exhalations , and so to make an operation , not only in clauso , but as it were in solido , and reduce the parts of the body expos'd , and perhaps the igneous corpuscles to act reciprocally upon one another , without any notable dissipation , or avolation of parts . to apply now what hath been said , to antimony ; i shall briefly set down an uncommon way that came into my mind of operating upon it . we took well powder'd ♁ , and well dry'd ( white ) chalk reduc'd likewise to powder ; with these in a large earthen pot or crucible , we made sss . having a care to make the lowermost and uppermost bed of chalk , and the last thicker than any of the rest , as also that none of the antimo-nial layers , were but of a moderate thickness , that the heat might penetrate them the better ; then the vessel , being cover'd , was put among the kindled coals of a good digestive furnace , ( not because such a one was necessary , but because 't was at hand ) where 't was kept for a competent time , which according to the bigness of the pot , and the strength of the fire , may be sometimes or hours , sometimes a day and a half , and sometimes two days or better . the ii. pentade . experiment i. a very uncommon way of making a cale of gold. 't is known that most chymists , and many physicians , have a superlative esteem for the medicinal vertues of gold , and the preparations of it . and upon this ground , divers of them have long been , and still are solicitous to make calces of gold by differing ways ; most of them laborious , and some of them scarce to be safely wrought and us'd in physick : wherefore i shall , i presume , be easily pardon'd , if i here set down a way that came into my mind , and that i have sometimes us'd to make a preparation wherein gold is reduc'd to very minute parts , without the help of mercury , or of any precipitation made by sharp salts , whether acid or lixivial . we took then refin'd gold , and dissolv'd it in clean and spirituous aqua regia , and instead of precipitating the clear solution with oyl of tartar per deliquium , as is usually done , or with spirit of sal armoniac , or other volatile urinous spirits , we first with a very modest heat drew off the superfluous liquor ; whereby the gold with the remaining part of the menstruum , was left in the appearance of a thick and oleous liquor . this done , we pour'd upon it a treble weight of vinous spirit totally inflammable and in a short time , we had , as we expected , a very subtil powder , or high colour'd calx of gold , that subsided at the bottom ; the menstruum being strangely dulcifi'd as to tast , and become fragrant in point of smell when a very few days were past , we decanted the liquor , and put on it fresh ardent spirit , and leaving them a while together , there subsided the like well colour'd calx more plentifully than the first time . i know not , to add that upon the by , whether it may , or may not be worth while to try to discover whether this dulcifi'd a. r. spirituosa being drawn off from the subsiding gold , may have acquir'd any virtue from the open'd metal . some tryals seeming to argue that the openness of this calx made it fit to be easily wrought upon by a menstruum that would not touch water-gold , as they call the common calx made by quartation , nor yet leaf-gold , such as the apothecaries imploy ; but however the menstruum has acquir'd such qualities as make it seem likely to prove an useful medicine , which yet i refer to tryal . by the way we pitch'd upon to make this powder of gold , it seem'd probable , that it would not ( at least ) be less subtil , and yet would be more mild , than common preparations ; and nevertheless we thought it might , perhaps , make it yet more secure , if we should , as we did , put upon it a totally ardent vinous spirit , and burn it off once , twice , or thrice , to carry off with it any little corosive or saline particles ▪ that may have still adher'd to the metalline ones . n. b. the spirituous aqua regia , mention'd in the process , is so call'd by me , partly to distinguish it from the common aqua regia , and partly because 't is indeed of a more spirituous nature than the common , being compos'd without any gross salt ; such as * but only of spirits . this menstruum i made for some particular uses : and tho it works more slowly than the common chrysulca , yet i often prefer it to this , as that which i can imploy to some uncommon purposes , and as it may probably be a more innocent menstruum in making preparations of sol , design'd for medicinal uses . i make it very easily , by mixing one part of good spirit of salt , with two parts of strong spirit of niter , or ( when 't is not to be us'd for medicines ) of common , but clean aqua fortis . scholium . the above recited tryal was made as 't is deliver'd ; but some circumstances that i took notice of , and particularly some grains of powder that , tho mingl'd with the rest , were shining , as if they had been extreamly minute , and bright filings of gold. these circumstances , i say , made me suspect that the success might much depend upon particular and nice circumstances that may need more exact tryal , than i had then occasion to make ; and therefore it may be fit that the experiment be heedfully repeated . it may also be try'd whether the imploying common a. r. instead of the spirituous , will much vary the experiment . experiment ii. to try how much volatile salt an assign'd quantity of water would dissolve , we took ℥ iii of distill'd water , and put into it by degrees , some dry salt of salt armoniac ( that was very white , and compact enough ) keeping the liquor in digestion for a pretty while , that it might have time to dissolve as much as it could . when we found it would dissolve no more in a moderate heat , we took it off , and found that after standing some hours in the cold there fell to the lower part of the glass , and setled there , a pretty quantity of salt , which we guess'd to be about ʒii , which being deducted from ℥ ii , that had been in all put in , there remained ℥ i and ʒvi in the liquor , which by this account had dissolv'd at least half its weight of salt. scholium . i desire it may not be thought strange , if among our chymical experiments , some few shall be here and there met with , that are much less elaborate or promising than others that i could easily have inserted in their rooms ; for i did it on set purpose , partly because oftentimes ( as was intimated at the beginning of the chapter ) some more simple or seemingly less valuable experiments may be fitter materials , than more curious ones , for the natural history we would promote ; and partly to give an example , if mine can signifie any thing , of not disdaining to register some things that seem mean ; if by the light they afford , or the uses they may be apply'd to , they compensate the want of lustre , and of immediate utility . and the substance of this scholium i desire may be mentally transferr'd , as occasion shall require , to those following chapters that treat of chymical experiments . experiment . iii. perhaps some chymists will think that the following memoir may give hints that may be of use on several occasions , both for other purposes , and for theirs , that would draw tinctures from several bodies , that will not afford them in simple spirit of wine , tho well rectifi'd . the simple spirit of good french verdigreas , being once or twice abstracted from as much salt of tartar as it would dissolve in the cold ; left the salt easily susible , and dissoluble in highly rectifi'd spirit of wine . experiment iv. i have not been unacquainted with some curious and elaborate preparations of that noble flower the rose ; and experience hath convinc'd me that t is possible , whatever most chymists think of it , to obtain from roses a true essential oyl , that mixes not with water , and is exceeding fragrant : but there are several that are so far from believing that an essential oyl may be obtain'd from roses , without being in the form of a butter , but in a liquid one like oyl of cloves , or wormwood , that they doubt whether a true spiritus ardens can be obtain'd from them , without addition of wine , or some such inflamable liquor . i shall here transcribe the following note , as containing a more simple and easie preparation ( than any of those before mention'd ) of the ardent spirit of those flowers , and therefore more suitable to the design of the whole chapter . to make an inflammable spirit of roses . two bushels of damask roses ( together with a good number of red rose-buds ) being beaten , and put into a vessel with water amounting to about gallons , were mingled with about a quart of ale-yest , and kept in fermentation for about or days ( the weather being cold for the season ) and then being distill'd per vesicam , afforded us a spiritus ardens . experiment . v. an experiment about the chymical analysis of pearls . we took ℥ ii of seed pearl , that were carefully bought for oriental , and without breaking them , put them into a retort , and distil'd them in a sand-furnace by degrees of fire , giving a strong one at the last . by this means we had a little black oyl swimming upon the spirit , which was also dark and muddy , as if incorporated with some more oyl . the weight of both these liquors was grains , besides which there stuck to almost all the upper part of the retort , a thin film of oyl , which together with a streak of the like reaching to the bottom of the receiver , we estimated at grains more , and so reckon'd grains for the weight of the whole ascended matter . the caput mortuum amounted to full the remainng weight of two ounces . the empyreumatical liquors that came over , smell'd much like those of harts-horn , and the spirit was found to belong , as we expected , to the tribe of urinous ones , or , as many now call them volatile alcaly's for it readily hiss'd and produc'd bubbles , with good spirit of salt turn'd syrup of violets green , and being drop'd into solution of sublimate , turn'd that white ; to omit another way or two , by which i examin'd it . the oyl that stuck to the retort , and which was faetid , like that of harts-horn , did easily dissolve in dephlegm'd spirit of wine , and afforded a reddish brown solution . the caput mortuum was very black , and some grains of it were found readily enough dissoluble in spirit of vinegar . being calcin'd in a well cover'd crucible , with a strong fire ( for a moderate one will not do it , unless it be long ) we reduc'd them to be purely white , and to a weight less by some grains than an ounce , and ʒiii and we found , as we expected , that being pulveriz'd , this calx tasted hot and bitterish upon the tongue , like good calx vive , and was not only of an alcalisate , but a lixival nature : for besides that it presently turn'd syrup of violets green , it quickly afforded an orange colour'd precipitate , with solution of sublimate . strange reports , in ii. parts . address'd to a vertuoso , friend to the author . advertisement . i presume , sir , you may yet remember , what i wrote about the nature and scope of my collection of strange reports , in an essay which take's its title from them ; and which i was encouraged to make by the example and authority of aristotle . and therefore i shall desire , that to save your trouble and my own , that paper may serve for a preface to that which follows . about which , supposing this request to be granted , i shall need to give you at present but this short advertisement ; that for distinction's sake , i thought fit to divide the ensuing particulars into two parts , because they are indeed of two sorts : one relating to things purely natural , and the other consisting of phaenomena , that are , of seem to be , of a supernatural kind or order . the first set of particulars belonging to each of the two foremention'd parts , has prefixt to it the title of the first section , tho it be not at this time attended by a second ; because 't is design'd , that god permitting , it shall be so hereafter , when i shall get time to pick up out of my adversaria , and other memoirs , particulars fit to have plac'd in the list of strange reports . i must likewise give you notice , that you are not to expect the ii. part at this time : discretion forbidding me to let that appear , till i see what entertainment will be given to the i. part , that consists but of relations far less strange than those that make up the other part. strange reports . part . i. section . i. relating to a judicious virtuoso , that a physician of bruxels a while since affirm'd to me , that he himself had prepar'd or resuscitable plants , one of which he had presented to the marquess of castel rodrigo , now governor of the spanish netherlands , where this virtuoso had not long since been . relating this , i say , to this gentleman , and enquiring of him , whether he had seen this resuscitable plant ; he answered me , that he had never seen nor heard of it ; but told me on this occasion , that coming to deal with an apothecary of namier , if i misremember not the name , much esteem'd for his extraordinary skill in chymistry about some choice preparations , wherewith this man's shop was furnish'd the apothecary told the virtuoso , that he had really prepar'd resufcitable plants , a different way from that which others pretended to , and that he could prepare a great variety of them . and when having enquir'd of the virtuoso , whether he himself had seen any of these prepar'd plants , he assur'd me , that he had seen not only some , but many ; i then upon farther enquiry how they appear'd , learned that the chymist had divers of them in distinct glass-bottles ; that the apparitions that were exhibited , shew'd not the peculiar colours , but only the shape of the plant ; but this so genuinely that he could perfectly distinguish and easily know it to be such or such a plant instancing particularly in carduus benedictus , and camomile . and the difference betwixt this way of exhibiting plants , and that which is mention'd by quercetan , and pretended to by others ; i found by this gentleman's answers , to consist chiefly in these two things : the first , that the apothecary's plants did not as the others seem to grow up into the air included in a seal'd vial , but were seen as growing in a clear liquor , wherewith the bottle that contain'd it was almost fill'd ; and the next , that whereas to make the apparition , mention'd by quercetan , and others , the application of an actual heat ( as that of a lamp , or the sun-beams , or the like ) is affirm'd to be requisite , upon the absence of which the phantastical plant relapses into its ashes . in the formation of the apothecaries vegetables , he doth not employ any actual heat , but ( which may seem more strange ) only the shaking , of the bottle , for upon that agitation the prepar'd ashes or powder being this'd from the bottom , and dispers'd quite through the liquor , when the glass is set by in a quiet place , the scatter'd particles by degrees so convene , as to compose a model of the plant they once belong'd to . and heat not being requisite to their formation , these plants do not quickly , as the pelonian physician 's phantastick vegetable , recorded by quercetan , fall back into a powder ; but if let alone , continu'd a great while , until the preparer think fit by a gentle agitation of the bottle , to dissolve the loose contexture of it . relation ii. i met the other day with a very intelligent person , well vers'd in chymistry , not credulous , and in a word very well worthy of credit , who assur'd me , that he had himself seen a few years ago at mentz , in the hands of one monsieur p — r , a gentleman of switzer-land , and a virtuoso , a piece of glass about the bigness of a shilling , or somewhat bigger ; which was red and pretty transparent like glass of antimony made per se , and which this monsieur p. affirm'd to the relator , that he hammer'd before the present elector of heidelberg ( to whom i told him , i had the honour to be known , and ) by whom the relator was about that time imploy'd . and this monsieur p. being his intimate acquaintance , and perceiving that he was , ( as he well might be ) indispos'd to believe so strange a thing , after he had confest the glass to have been given him by an excellent chymist in his country ( switzerland ) ; this gentleman , i say , at the relators earnest request , gave him leave for his satisfaction , to lay the piece of glass upon an anvil , and to strike seven or eight strokes with a hammer upon it ; by which means he found , that tho it was nor malleable ( at least in the state it then was ) like neal'd silver , since it began to crack at the edges like silver that is over-hammer'd ; yet it did really stretch under the hammer , growing more thin on the beaten part , and having visible marks or impressions made on it by the edg of the hammer . relation iii. a pious and learned school-master , that ventur'd to stay in london in the great plague , and was much employ'd , as some friends of mine that knew him , and commended him , assur'd me , to visit the sick , and distribute alms and relief to them , went indiscriminately to all sorts of infected , and even dying persons , to the number , as he told me , of nine hundred , or a thousand ; and being ask'd by me about the infection of other things than walls , he told me , that being once call'd to administer some ghostly comfort to a poor woman that had buried some children of the plague , he found the room so little , that it scarce held any more than the bed whereon she lay sick , and an open coffin wherein he saw her husband lye dead of the same disease , whom the wife soon after follow'd . in this little close room they affirm'd to him , that the contagious steams had produc'd spots on the very wall ; and when i ask'd , whether he himself had seen them , he answer'd , that he had not ; but yet was inclin'd to believe the thing to be true , not only upon the score of the relators , but because he had observ'd the like in his own study , which being divided only by a wall from some rooms of a house , which the owner had turn'd into a kind of a pest-house , and in which , numbers had dyed in a short time ; he took notice that the white wall of his study was ( since the sickness rag'd , without any other cause that he could imagine ) blemish'd in divers places with spots , like those of infected persons ; when ( to add that upon the by ) i inquir'd what antidote he us'd ; he replied , that next the protection of god , which so many sad objects made him the more fervently implore , and a constant fearlesness , the only preservative he us'd , besides good diet , were half a spoonful , or a spoonful of brandy five or six times a day , especially when he went into infected places , and the bigness of a small nut or less , of a root of spanish angelica , of which he held in his mouth the quantity of a pepper-corn , or somewhat less , as often as he thought there was need . relation iv. an ingenious person , and very worthy of credit , inform'd me the other day , in answer to some questions that i propos'd to him , that he was imploy'd some years ago by a german physician ( whose name he told me ) to distil a certain mineral not unknown to me , which he perform'd in a naked fire , with so good success , that he had from about half a pound of the mineral , near ʒiii of the liquor ; this he included in a glass with a bubble , and a slender neck like one of my weather-glasses ; but tho the liquor at first reach'd not above the bubble , but only fill'd it to the bottom of the pipe ; yet as the moon increas'd , this liquor , as the doctor expected , by degrees expanded it self in the glass , so that about the full - moon , it reach'd about an inch into the pipe , and upon the decrease of the moon , it subsided by degrees to the bottom of the pipe. and when i ask'd , whether the vessel were carefully stopt , he answer'd , that it was not only so , but hermetically seal'd like one of my thermometers with spirit of wine , which he had seen . this the relator averr'd to me upon his own observation , and being desir'd , he readily gave me a description of the mineral , and a direction where to procure it , ( which i am now endeavouring to do ) adding that the same doctor made the like tryal with another mineral , akin to this , with which my having heard that such an experiment had been done , gave me occasion to propose him the question . relation v. an inquisitive traveller that not long since waited on a german prince addicted to chymistry , and was imploy'd by him in his private laboratory ; being ask'd by me some questions about ore of bismute or tin-glass , whereof there is said to be a mine in that prince's territories , and in particular , whether he had observ'd any thing of the varying bulk of a strange liquor obtainable from it : he answer'd me to this effect , that he had had occasion to make many tryals upon this mineral , and that particularly by his prince's command , he had distill'd a considerable quantity of a certain sort of it ( because it yields but very little spirit ) and that he thereby obtain'd a liquor , which being by rectification freed from its superfluous phlegm , amounted to about half a pint. this liquor was put into a vial , which it almost half fill'd . this vial being exactly stop'd , was set aside in a quiet place , where , ( as the prince expected ) as the light of the moon increas'd , from the new - moon towards the full ; so this liquor gradually swell'd , and that not in a hardly perceptible degree , but very manifestly and confiderably ; so that when the moon was full , the liquor reached almost to the top of the glass , and during her wane , as the light decreas'd , so did the bulk of the liquor , which was always least at the new - moon . i ask'd him if any tryal had been made , whether the weight of this spirit varied with the bulk , and he frankly confess'd to me , that it had not come into his mind ; but for what is above related of the increment and decrement as to quantity affirm'd to me , that he himself , as well as his prince had several times observ'd it ; and he also readily told me the way he used in making the distillation , which he said , exacted an intense degree of fire . relation vi. an inquisitive person , that having gone through his studies in the university , travell'd throgh divers countries to make himself the more fit for the profession of physick , answer'd me , that having resided for some time in prussia , he had more than once or twice ( and that in differing places ) observ'd , as others in his company also did , that the fisher-men in breaking the ice of long frozen places , and taking out thence confiderable masses of ice , did several times find in them swallows , sometimes numerous enough , that were so inclos'd in the ice , that unless by breaking or thawing it , they could not be gotten out of it . and he further answer'd me , that when these lumps or masses of ice came to be thaw'd in their german stoves , the swallows , that lay as dead before , would revive , and perhaps fly about the room ; but did not long survive their recovery out of their insensible state ; some dying again in few hours , others the next day , or perhaps the third ; but sew or none , that he observ'd , living beyond the fourth or the fifth ; which immature death , my relator judg'd to be caus'd by their having no appetite to eat , which inappetency made them dye starv'd . but as the conjecture may be true as to those that liv'd for some days , so it seems not like that those that perish'd in few hours , dyed meerly of hunger ; and as for them that were starv'd to death , i should suspect that they were starv'd , not so much for want of appetite , as for want of such animals as they us'd to feed on , especially flies , which they could not get in winter . relation vii . an inquisitive gentleman lately return'd from jamaica , where he was imploy'd by the governour to make discoveries of natural things , answer'd me ( this morning ) that he had seen in that island great number of trees that bear the silken cotten , that he found many of them to surpass in bigness and height the larger sort of our english oaks ; and that on a mountain that many went to visit out of curiosity , to view a stupendious silk-cotton tree , he saw its bulk , and many affirm'd to him , and it was the general tradition of the country , which he saw no cause to disbelieve , that this prodigious tree was in the body no less than yards about , that is , more than foot in compass . the same curious traveller told me he saw a cannow made of the hollow'd trunk of one of these silk-cotton trees , which after all that had been taken off to give it the shape of a vessel fit for service , was foot about , and of at least a proportionable length . relation viii . a merchant rich and judicious , and more addicted to letters than is usual to men of his calling , being return'd into england , from some of the remoter parts of the east-indies , to satisfy my curiosity about a strange tradition of several navigators about a more than one way extraordinary in-draught of the sea on the coast of a great island of the southern ocean , sent me the ensuing relation , which tho it contains something manifestly fabulous , but easily distinguishable from the rest , i give you in the relators own words , being unwilling to alter any thing till i can see him again , and propose my scruples to him . at campar and rakan , on the east coast of sumatra , is in the rivers mouth ( to a certain distance ) at each new and full-moon , a violent in-draught of the sea , ( call'd bunna ) which approacheth with an hideous noise , and mountain-high , so that whatsoever opposeth it , perisheth . it s approach is in three parts , the first high , but not so terrible ; the second is high , black and horrid ; the third is low , and of gentle motion ; before its approach , it giveth so fair warning , that the people may eat , and bath themselves , before they weigh anchor ; but when they weigh , they must row hard against it , and when its fury is past , follow with it , till they return to their anchor place . the true reason whereof the inhabitants cannot discover : but ( as if greece only were not the mother of fabulous traditions ) these poor natives fabulize , that at campar ( where is the greatest bunna ) in former ages , there was a princess , who , to shun the rape of an insolent casfree slave , ran into the seas mouth ; but the slave still pursuing her , and after him the princess's little-dog ; all perish'd and thus ( by a new metamorphosis ) these three waves perpetuate their commemoration . that afterwards a bold fellow hoping to divert this bunna from campar ( by advice of some wizards ) row'd up against that first part of the torrent , and filling a bottle of its water , which he immediately stopt up close , he betook himself to rakan ( not far distant ) and pour'd it out into that rivers mouth , which brought the bunna thither also , tho it left not campar ; but that fellow suddenly after dying , none durst since attempt the like , else the natives fancy it may still be done . my humble opinion is , ( adds my relator ) that the mouths of those rivers being choakt up with their sand-banks , and so render'd very shallow ; when the great spring-tydes come roaring over those shoals ( at the new and full-moons ) out of the malacca streights , the first influx is irresistible , by such small vessels as use that port , ( especially if attended with dark weather or stormy gusts ) so that they are forc'd to weigh and bear up against it for fear of being strandded and split . in which sentiment i rest , till i can attain a more prevalent reason . relation ix . a gentleman that had travell'd far and observ'd much , related to me , that being off the coast of mosambique , between the th and last days of september , the captain of the great portugal ship they were in , walking to and fro upon the deck , spy'd a great way off , a very little dark cloud or blackish spot in the sky : whereupon , tho the weather were fair , he made all the hast he possibly could to provide for a great storm , by taking in the sails , &c. and thó for a while the sky continu'd clear , and they had no signs of an imminent change ; but that when the cloud approacht , the wind that had till then fill'd , their sails ceas'd , and the sea became calmer than before : but presently after they had a furious hurricane , which turn'd their ship quite round many times one after another , as if it were an aerial whirl-pool , which lasted for above two hours , and then left them , seeming to have a progressive motion , as whirl-pools in rivers often have . relation x. an ingenious practitioner of physick , accompany'd by one of the same profession , assur'd me with great asseveration , that some while since , being at a place in the country near amsterdam , where there liv'd a kind of a farmer , who ( tho illiterate enough ) was reputed very curious ; this person shew'd him , among other things , a considerable quantity of quicksilver that was altogether of the colour of gold. and , to answer my scruple , this relator added , that the colour did not belong only to the surface of the whole mass ; but having purposely ( with water ) divided it into many globules , each of them retain'd the same rich colour . and he further told me , that the possessor of this yellow mercury , having put some of it over a fire in a convenient vessel , it quickly lost its fludity , and was precipitated into a red powder ; about which he hop'd to learn some notable things at his next visit to the author : but that having been too long delay'd ; when he came to the place again , he found to his great grief that the master was dead , and his relations were , or pretended to be , ignorant of his secrets . a very learned and experienc'd physician , made me a visit to give me notice , that a few days before he had receiv'd one in the night from a couple of strangers , one of whom by some things that he saw him do , he judg'd to be ( what they call ) an adeptus , who besides a thing far more rare and valuable , shew'd him as a curiosity , a runing mercury of a lovely green. and when i ask'd my judicious relator , whether he had broken the fluid mass into drops , to observe whether the colour were that only of the surface , or of the whole mass ? he answer'd , that he purposely laid it upon a rough body , as a carpet , and found the globules , whereinto 't was by this means divided , to be of the same fine green that had beautify'd the whole mass . these relations , tho they had come to me from less credible persons than those i receiv'd them from , i should not hastily have rejected , because of some odd and fine colorations of runing mercury , that i have my self observ'd , but here forbear to mention , because they belong to another paper . finis . notes, typically marginal, from the original text notes for div a -e * this refers to the manuscript that was sent to mr. o. and is left to shew the intention of the author . notes for div a -e lib. . cap. . see exper. . cent. . decemb. . nov. . . notes for div a -e this famous philosopher in his little tract , whose title some render de mirandis auditionibus , scrupled not to comprise without method , divers reports , uncertain or fabulous , nor to insert several that were not so cautiously admitted as those recited in the following . collection . notes for div a -e january , . experimental philosophy, in three books containing new experiments microscopical, mercurial, magnetical : with some deductions, and probable hypotheses, raised from them, in avouchment and illustration of the now famous atomical hypothesis / by henry power ... power, henry, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) experimental philosophy, in three books containing new experiments microscopical, mercurial, magnetical : with some deductions, and probable hypotheses, raised from them, in avouchment and illustration of the now famous atomical hypothesis / by henry power ... power, henry, - . [ ], , [ ] p. [ ] folded leaf of plates : ill. printed by t. roycroft, for john martin and james allestry ..., london : . books [ ]- have special t.p., dated . "subterraneous experiments, or, observations about cole-mines" has half-title. errata: p. 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ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng science -- early works to . physics -- early works to . microscopy -- early works to . microscopes -- early works to . - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - judith siefring sampled and proofread - judith siefring text and markup reviewed and edited - pfs batch review (qc) and xml conversion imprimatur , geo. stradling , s. t. p. rev. in christo patr. d. gilb. episc. loud . à sac. domestic . ex aed sab. aug. . . experimental philosophy , in three-books : containing new experiments microscopical , mercurial , magnetical . with some deductions , and probable hypotheses , raised from them , in avouchment and illustration of the now famous atomical hypothesis . by henry power , dr. of physick . perspicillum ( microscopicum scilicet ) si vidisset democritus , exiluisset fortè ; & modum videndi atomum ( quam ille invisibilem omninò affirmavit ) inventum fuisse putâsset . fr. verulam . lib. . novi organi , sect . . hinc igitur facillimè intelligere possumus , quam stuliè , quam inaniter sese venditat humana sapientia , quóve ferantur nostra ingenia , nisi recta ratione , experientiáque ( scientiarum omnium magistra ) nitantur & opin●●●is salebras accuratè vitent . muffet . de insect . cap. . pag. . london , printed by t. roycroft , for john martin , and james allestry , at the bell in s. pauls church-yard . . the preface to the ingenious reader . dioptrical glasses ( which are now wrought up to that height and curiosity we see ) are but a modern invention : antiquity gives us not the least hint thereof , neither do their records furnish us with any thing that does antedate our late discoveries of the telescope , or microscope . the want of which incomparable artifice made them not onely erre in their fond coelestial hypothesis , and crystalline wheel-work of the heavens above us , but also in their nearer observations of the minute bodies and smallest sort of creatures about us , which have been by them but sleightly and perfunctorily described , as being the disregarded pieces and huslement of the creation ; when ( alas ! ) those sons of sense were not able to see how curiously the minutest things of the world are wrought , and with what eminent signatures of divine providence they were inrich'd and embellish'd , without our dioptrical assistance . neither do i think that the aged world stands now in need of spectacles , more than it did in its primitive strength and lustre : for howsoever though the faculties of the soul of our primitive father adam might be more quick & perspicacious in apprehension , than those of our lapsed selves ; yet certainly the constitution of adam's organs was not divers from ours , nor different from those of his fallen self , so that he could never discern those distant , or minute objects by natural vision , as we do by the artificial advantages of the telescope and microscope . so that certainly the secondary planets of saturn and jupiter and his ansulary appearances , the maculae solis , and lunations of the inferiour planets , were as obscure to him as unknown to his posterity ; onely what he might ingeniously ghess at by the analogie of things in nature , and some other advantageous circumstances . and as those remote objects were beyond the reach of his natural opticks , so doubtless the minute atoms and particles of matter , were as unknown to him , as they are yet unseen by us : for certainly both his and our eyes were framed by providence in analogie to the rest of our senses , and as might best manage this particular engine we call the body , and best agree with the place of our habitation ( the earth and elements we were to converse with ) and not to be critical spectators , surveyors , and adaequate judges of the immense vniverse : and therefore it hath often seem'd to me beyond an ordinary probability , and somthing more than fancy ( how paradoxical soever the conjecture may seem ) to think , that the least bodies we are able to see with our naked eyes , are but middle proportionals ( as it were ) 'twixt the greatest and smallest bodies in nature , which two extremes lye equally beyond the reach of humane sensation : for as on the one side they are but narrow souls , and not worthy the name of philosophers , that think any body can be too great or too too vast in its dimensions ; so likewise , are they as inapprehensive , and of the same litter with the former , that on the other side think the particles of matter may be too little , and that nature is stinted at an atom , and must have a non ultra of her subdivisions . such , i am sure , our modern engine ( the microscope ) wil ocularly evince and unlearn them their opinions again : for herein you may see what a subtil divider of matter nature is ; herein we can see what the illustrious wits of the atomical and corpuscularian philosophers durst but imagine , even the very atoms and their reputed indivisibles and least realities of matter , nay the curious mechanism and organical contrivance of those minute animals , with their distinct parts , colour , figure and motion , whose whole bulk were to them almost invisible : so that were aristotle now alive , he might write a new history of animals ; for the first tome of zoography is still wanting , the naturalists hitherto having onely described unto us the larger and more voluminous sort of animals , as bulls , bears , tygers , &c. whilst they have regardlesly pass'd by the insectile automata , ( those living-exiguities ) with only a bare mention of their names , whereas in these prety engines ( by an incomparable stenography of providence ) are lodged all the perfections of the largest animals ; they have the same organs of body , multiplicity of parts , variety of motions , diversity of figures , severality of functions with those of the largest size : and that which augments the miracle , is , that all these in so narrow a room neither interfere nor impede one another in their operations . who therefore with the learned doctor , admires not regiomontanus his fly beyond his eagle , and wonders not more at the operation of two souls in those minute bodies , than but one in the trunk of a cedar ? ruder heads stand amazed at those prodigious and colossean pieces of nature , as whales , elephants , and dromedaries ; but in these narrow engines there is more curious mathematicks , and the architecture of these little fabricks more neatly set forth the wisdom of their maker . now as matter may be great or little , yet never shrink by subdivision into nothing ; so , is it not probable , that motion also may be indefinitely swift or slow , and yet never come to a quiescency ? and so consequently there can be no rest in nature , more than a vacuity in matter . the following observations seem to make out , that the minute particles of most ( if not all ) bodies are constantly in some kind of motion , and that motion may be both invisibly and unintelligibly slow , as well as swift , and probably is as unseparable an attribute to bodies , as well as extension is . and indeed , if the very nature of fluidity consist in the intestine motion of the parts of that body call'd fluid , as des-cartes happily supposed , and m r. boyle has more happily demonstrated , why may we not be bold both to think and say , that there is no such thing in the world as an absolute quiescence ? for . the greatest part of the world ( viz. the aetherial medium ( wherein all the stars and planets do swim ) is now confess'd by all to be fluid , and so , consequently , in a perpetual motion . . all the fixed lights of heaven are generally concluded to be pure fire , and so consequently fluid also , and then subconsequentially in motion also ; not to mention the dinetical rotations of their whole bodies , which every one is supposed to have , as wel as our sun : and as for the opace and planetary bodies of the vniverse , they are all porous , and the aetherial matter is continually streaming through them , their internal fire and heat constantly subliming atoms out of them , the magnetical atoms continually playing about them : not to mention also their dinetical motions about their own axes , and circumrevolutions about their central suns : so that , is it not , i say , more than probable , that rest and quiescency is a meer peripatetical notion , and that the supreme being ( who is activity it self ) never made any thing inactive or utterly devoid of motion ? hence wil unavoidable follow some other principles of the ever-to-be-admired des-cartes : . that as matter is made greater or less , by addition or subduction of parts , so is motion made swifter or slower by addition given to the movent , by other contiguous bodies more swiftly moving , or by subduction of it by bodies slowlier moved . . as the parts of matter can be transfer'd from one body to another , and as long as they remain united , would remain so for ever : so motion may be translated from one body to another ; but when it is not transfer'd , it would remain in that body for ever . but these sublime speculations i shall with more confidence treat of in another place ; the speculation of motion , and its origin , being , as i conceive , one of the obscurest things in nature . and therfore at present we shal keep within the compass of the microscope , and look at nothing further than what we can discover therein : the knowledge of man ( saith the learn'd verulam ) hath hitherto been determin'd by the view or sight , so that whatsoever is invisible , either in respect of the fineness of the body it self , or the smalness of the parts , or of the subtilty of its motion , is little enquired ; and yet these be the things that govern nature principally : how much therefore are we oblig'd to modern industry , that of late hath discover'd this advantageous artifice of glasses , and furnish'd our necessities with such artificial eys , that now neither the fineness of the body , nor the smalness of the parts , nor the subtilty of its motion , can secure them from our discovery ? and indeed , if the dioptricks further prevail , and that darling art could but perform what the theorists in conical sections demonstrate , we might hope , ere long , to see the magnetical effluviums of the loadstone , the solary atoms of light ( or globuli aetherei of the renowned des-cartes ) the springy particles of air , the constant and tumultuary motion of the atoms of all fluid bodies , and those infinite , insensible corpuscles ( which daily produce those prodigious ( though common ) effects amongst us : ) and though these hopes be vastly hyperbolical , yet who can tel how far mechanical industry may prevail ; for the process of art is indefinite , and who can set a non-ultra to her endevours ? i am sure , if we look backwards at what the dioptriks hath already perform'd , we cannot but conclude such prognosticks to be within the circle of possibilities , and perhaps not out of the reach of futurity to exhibit : however this i am sure of , that without some such mechanical assistance , our best philosophers will but prove empty conjecturalists , and their profoundest speculations herein , but gloss'd outside fallacies ; like our stage-scenes , or perspectives , that shew things inwards , when they are but superficial paintings . for , to conclude with that doubly honourable ( both for his parts and parentage ) m r. boyle , when a writer , saith he , acquaints me onely with his own thoughts or conjectures , without inriching his discourse with any real experiment or observation , if he be mistaken in his ratiotination , i am in some danger of erring with him , and at least am like to lose my time , without receiving any valuable compensation for so great a loss : but if a writer endevours , by delivering new and real observations or experiments , to credit his opinions , the case is much otherwayes ; for , let his opinions be never so false ( his experiments being true ) i am not oblig'd to believe the former , and am left at my liberty to benefit my self by the latter : and though he have erroneously superstructed upon his experiments , yet the foundation being solid , a more wary builder may be very much further'd by it , in the erection of a more judicious and consistent fabrick . henry power . from new-hall , near hallifax , . aug. . microscopical observations . observat. i. of the flea . it seems as big as a little prawn or shrimp , with a small head , but in it two fair eyes globular and prominent of the circumference of a spangle ; in the midst of which you might ( through the diaphanous cornea . ) see a round blackish spot , which is the pupil or apple of the eye , beset round with a greenish glistering circle , which is the iris , ( as vibrissant and glorious as a cats eye ) most admirable to behold . how critical is nature in all her works ! that to so small and contemptible an animal hath given such an exquisite fabrick of the eye , even to the distinction of parts . had our famous muffet but seen them , he would not have spoke so doubtfully as he did : oculos ( saith he , speaking of flea's ) habere , verisimile est , tùm quod suos eligunt recessus , tùm quod appetente luce so subducunt . he has also a very long neck , jemmar'd like the tail of a lobstar , which he could nimbly move any way ; his head , body , and limbs also , be all of blackish armour-work , shining and polished with jemmar's , most excellently contrived for the nimble motion of all the parts : nature having armed him thus cap-a-pe like a curiazier in warr , that he might not be hurt by the great leaps he takes ; to which purpose also he hath so excellent an eye , the better to look before he leap : to which add this advantageous contrivance of the joynts of his hinder legs which bend backwards towards his belly , and the knees or flexure of his fore-legs forwards ( as in most quadrupeds ) that he might thereby take a better rise when he leaps . his feet are slit into claws or talons , that he might the better stick to what he lights upon : he hath also two pointers before which grow out of the forehead , by which he tryes and feels all objects , whether they be edible or no. his neck , body , and limbs are also all beset with hairs and bristles , like so many turn-pikes , as if his armour was palysado'd about by them . at his snout is fixed a proboscis , or hollow trunk or probe , by which he both punches the skin , and sucks the blood through it , leaving that central spot in the middle of the flea-biting , where the probe entred . one would wonder at the great strength lodged in so small a receptacle , and that he is not able onely to carry his whole armour about him , but will frisk and curvet so nimbly with it : stick a large brass pin through his tayl and he will readily drag it away . i have seen a chain of gold ( at tredescants famous reconditory of novelties ) of three hundred links , though not above an inch long , both fastned to , and drawn away by a flea . such a like one it seems as our muffet tells that one marcus an english-man made . nay hear what he saith further , accepimus item à fide dignis , pulicem sic catena alligatum , currum aureum perfectè suis numeris absolutum , nullo negotio traxisse , id quod & artificis industriam & suas ipsius vires multùm commendat : yea , we have heard it credibly reported , saith he , that a flea hath not onely drawn a gold chain , but a golden charriot also with all its harness and accoutrements fixed to it , which did excellently set forth the artifice of the maker , and strength of the drawer ; so great is the mechanick power which providence has immur'd within these living walls of jet . observat. ii. the bee. the eye of a bee is of a protuberant oval figure , black and all foraminulous , drill'd full of innumerable holes like a grater or thimble ; and , which is more wonderful , we could plainly see , that the holes were all of a square figure like an honey-comb , and stuck full of small hairs ( like the pores in our skin ) and which ( by blowing upon ) you might see waft to and fro ; all which neat particularities were more palpably discovered in the eye of a great humble-bee . now these holes were not absolute perforations , but onely dimples in their crustaceous tunica cornea ; which it seems is full of little pit-holes , like the cap of a thimble : for we cutt out the eye in a large humble-bee and crecket , and bared the shell or horney coat of the eye ; and laying either the convex or concave side upwards ( upon the object plate ) i could easily perceive the little holes or dimples formerly mentioned . so that , by the favour of our microscope , i have seen more in one hour then that famous bee-master aristomachus did in his fifty years contemplation of those laborious insects . if you divide the bee ( or humble-bee especially ) near the neck , you shall , without help of the glasse , see the heart beat most lively , which is a white pulsing vesicle . the stings in all bees are hollow and tubulous ( like a shoomaker's-punch ) so that when they prick the flesh , they do also , through that channel , transfuse the poyson into it : for if you take a bee , wasp , or humble-bee especially , and gently squeeze her tayl , so that you may see the sting , you shall perceive a drop of diaphanous liquor at the very end of it , which if you wipe off , you shall distinctly see it renewed again , that humour passing down the cavity into the end thereof . but if you would see their common-wealth , laws , customs , military discipline , and their skill in tacticks and architecture , then read our english butler , an experimental and not theoretical writer on that subject . observat. iii. the common fly. it is a very pleasant insect to behold : her body is as it were from head to tayl studded with silver and black armour , stuck all over with great black bristles , like porcupine quills , set all in parallel order , with their ends pointing all towards the tayl ; her wings look like a sea-fan with black thick ribs or fibers , dispers'd and branch'd through them , which are webb'd between with a thin membrane or film , like a slice of muscovy-glasse : she hath a small head which she can move or turn any way : she hath six legs , but goes onely but upon four ; the two foremost she makes use of instead of hands , with which you may often see her wipe her mouth and nose , and take up any thing to eat . the other four legs are cloven and arm'd with little clea's or tallons ( like a catamount ) by which she layes hold on the rugosities and asperities of all bodies she walks over , even to the supportance of her self , though with her back downwards and perpendicularly invers'd to the horizon . to which purpose also the wisdom of nature hath endued her with another singular artifice , and that is a fuzzy kinde of substance like little sponges , with which she hath lined the soles of her feet , which substance is always repleated with a whitish viscous liquor ▪ which she can at pleasure squeeze out , and so sodder and be-glew her self to the plain she walks on , which otherways her gravity would hinder ( were it not for this contrivance ) especially when she walks in those inverted positions . but of all things her eyes are most remarkable , being exceeding large , ovally protuberant and most neatly dimpled with innumerable little cavities like a small grater or thimble , through which seeming perforations you may see a faint reddish colour ( which is the blood in the eyes , for if you prick a pin through the eye , you shall finde more blood there , then in all the rest of her body . ) the like foraminulous perforations or trelliced eyes are in all flyes , more conspicuously in carnivorous or flesh-flyes , in the stercorary or yellow flyes that feed upon cow-dung : the like eyes i have also found in divers other insects , as the shepherd-flye or spinster-flye , which muffet calls opilionum muscam ; also in cantharides or french-flyes ; also in all sorts of scarabees , black and spotted ; also in all sorts of moth-flyes , called by muffet , phalaenae-papiliones ; also in the may-fly , butter-flyes , scorpion-tail'd-fly , twinges , and earwigs ; most clearly in the sloe-black eye of the crecket , and in the large eye of the dragon-fly or adderbolt . many more observables there are in common flyes , as their vivacity ; for , when they appear desperate and quite forsaken of their forms , by virtue of the sun or warm ashes they will be revoked into life , and perform its functions again . had domitian thus busied himself in the contemplation of this animal , it had been an employment , not sometimes unworthy of caesar. for , to conclude with muffet ; dei verò virtutem quàm validè animalcula ista , parùm sanè valida , demonstrant ? contemplare enim vel minimum muscilionem , & quomodò in tantillo corpore , pedes , alas , oculos , promuscidem , aliaque membra , omni filo minora , concinnè adaptavit altissimus , edissere ! observat. iv. the gray , or horse-fly . her eye is an incomparable pleasant spectacle : 't is of a semisphaeroidal figure ; black and waved , or rather indented all over with a pure emerauld-green , so that it looks like green silk irish-stitch , drawn upon a black ground , and all latticed or chequered with dimples like common flyes , which makes the indentures look more pleasantly : her body looks like silver in frost-work , onely fring'd all over with white silk : her legs all joynted and knotted like the plant call'd equisetum or horse-tayl , and all hairy and slit at the ends into two toes , both which are lined with two white sponges or fuzballs as is pre-observ'd in common flyes . after her head is cut off , you shall most fairly see ( just at the setting on of her neck ) a pulsing particle ( which certainly is the heart ) to beat for half an hour most orderly and neatly through the skin . observat. v. the butter-fly . this animal might well deserve our observation without the assistance of a microscope ; for who does not admire the variegated diversity of colours in her expansed wings ? which do not onely out-vye the peacock in all his pride , but does as far out-go the strip'd bravery of the tulip , as that did solomon in all his glory : but view them in the microscope , and you may see the very streaks of the coelestial pencil that drew them . for the wings of the butterfly seem like a great plume of feathers , with a glystering splendour exceeding pleasant to behold , especially if the wings be strip'd with several colours : yea that small meal and dust of their wings ( which sticks to your fingers when you catch them ) is all small little feathers , which grow out of their wings ; and you may plainly see the twills by which they stick to the wings , and the holes in the wings , out of which they were pluck'd . nature having imp'd her wings ( for her better flight ) with those plumeous excrescences ; which shews how vastly * they were mistaken , that held this mealy dust to be an exudation of atoms out of their wings . her eye is large and globular ( but somewhat flattish ) white like alablaster , diced or bespeck'd here and there with black spots ( like checker'd marble ) all foraminous , both the white and black parts of it . i mean in a white butterfly , for in a red-wing'd butterfly , her eye is all black and full of perforations as in a common fly. the probe ( which you see lyes in her mouth in spiral contorsions , wound up like a spring , or like the twining tendrils of the vine , and which you may with a pin draw out to its full length ) seems to be hollow , and supplies the office both of mouth and tongue : for you shall see it ( if cutt out and laid on the object-plate ) to winde and coyl it self up like a spring , and then open again a long time together , and to have a transparent kinde of hollownesse quite throughout . nature having made it of a considerable length ( when extended ) that she might reach her nourishment , else the length of her legs would hinder the stooping of her head : she hath also fitted it with that spiral or cochleary contrivance , that so being drawn up into an helix , and retracted into the mouth , it might be no hinderance to her flight . observat. vi. a louse . she appears the bignesse of a large crecket , the body diaphanous and transparent , with three legs on either side , and two horns in the snout , all transparent and of gauntlet-work , having here and there hairs and bristles ; her feet likewise are slit into toes . her two eyes were like two black beads , gogled and protuberant , standing somewhat backwards on the side of her head behind her horns : she is blackish about the shoulders ; if she be laid on her back , you may perceive her body to be of escallop'd protuberances , diaphanous also , very handsome to behold . in this supine position of hers , there are two bloody darkish spots discernable , the greater in the midst of her body , and the lesser towards her tayl . in the centre of the middle spot there is a white film or bladder , which continually contracts and dilates its self upwards and downwards from the head towards the tayl ; and alwayes after every pulse of this white particle or vesicle , then followes the pulse of the great dark bloody spot , in which , or over which , the vesicle seems to swim . this we observ'd two or three hours together , as long as the louse lived ; and this motion of systole and diastole is most palpably seen , when the louse grows feeble and weak . i prick'd the white vesicle with a small needle and let out a little drop of blood ; and then viewing her again in the microscope , we could not perceive any life or motion after . in a greater louse you might see this pulsation of her heart through her back also ; but the white film or vesicle you cannot see till she be turn'd with her belly upwards . the lower dark spot ( which is the lesser towards the tayl ) dr. harvey probably conjectures to be the excrements in the guts of the louse , there reposited just before exclusion . hear how neatly sir theodore mayhern delivers his observation of this animal , taken in a puny microscope ; pediculorum oculos prominentes ( ope conspicilii ) cernes , & cornua , & crenatum corporis ambitum , totam substantiam diaphanam , per quam cordis & sanguinis tanquam in euripo indesinenter fluctuantis motum . observat. vii . a wood-louse , or wood-mite . there is a little white animal ( which you shall finde usually running over the leaves and covers of books , and in rotten wood ) which in shape and colour is like a louse , onely it has a swift motion , and runs by starts or stages ; you may kill it with a very little touch with your finger : this animal being fastened to the object-plate , by a little spattle , looks like polish'd silver , her whole body cased in annulary circles , all full of silver hairs , especially towards her tayl , with six legs , three on each side , whose extremities are arm'd with two black tallons , which you might see to move distinctly of themselves : two long moveable horns were fastened to her head , but revers'd and pointing backwards towards her tayl , with little branches and twigs ( like bezanteliers ) springing out of them . she hath two pointers also before , like a pair of pincers , which she moved laterally , all full of hairs , and two round knobs at the ends of them . her eyes are very protuberant , and globular , of a pure golden colour , most admirable to behold , especially when varnish'd with a full light , and most neatly latticed or mashed like a net ( as hath been pre-observ'd in other insects . ) and she seemed to have this peculiar artifice , that she can put out or draw in her eye at her pleasure ; so that sometimes we could see them far more prominent then at others ; and sometimes again the one eye more then the other : insomuch that in one of our critical observations , i could see more then a hemisphere of the eye at once ; so that what the processus ciliares does to our eyes , either in retracting or protruding the crystalline humour ( for helping the sight ) the same does the optick nerve ( it seems ) to the whole globe or bulk of their eyes . observat. viii . the house-spider . now let us see what we can discover in ovid's lydian-spinstresse , that proud madam which pallas , for her rivalship , transform'd into the spider ; which hath not onely the character of aristotle , but of solomon himself , for a wise and prudent animal , and therefore a fit residentiary in the court of kings . of domestick spiders there are two sorts ; one with longer legs and a little body , and the other contrariwise . the first eminent thing we found in these house-spiders , were their eyes , which in some were four , in some six , and in some eight , according to the proportion of their bulk , and longity of their legs . these eyes are placed all in the forefront of their head ( which is round , and without any neck ) all diaphanous and transparent , like a locket of diamonds , or a sett of round crystal-beads : so that well might muffet say of those philosophers that held them blinde , sanè coecutiunt illi summo meridie , qui videre ipsas non vident neque intelligunt : far better might he have said it , if his eyes had had the assistance of our microscope . neither wonder , why providence should be so anomalous in this animal more then in any other we know of ( argus his head being fix'd to arachne's shoulders . ) for , first : since they wanting a neck cannot move their head , it is requisite that defect should be supplyed by the multiplicity of eyes . secondly : since they were to live by catching so nimble a prey as a fly is , they ought to see her every way , and to take her per saltum ( as they do ) without any motion of their head to discover her ; which motion would have scar'd away so timorous an insect . they have a very puffy light body of an oval figure , covered with a sleek thin skin : which they change once a moneth , sayes muffet ; though i hardly believe they cast their spoils so often . their skin is not pellucid , for i could never discover any pulsing particle within them : she hath eight legs , four on each side , split into small oblong fingers at the ends , by which she makes her curious web-work both body and limbs is all stuck over with small silver hairs , which the very ayr will waft to and fro , as you may see in the microscope . observat. ix . the little white field-spider with short legs . there is a little white short-leg'd spider ( which you shall find plentifully amongst new hey , or in a sweating hey-mough ) which is a glorious spectacle to behold ; for her body is like white amber imboss'd all over with black knobs , out of every one of which grow bristles or prickles like whin-pricks perfectly taper-grown . and ( which is most admirable ) we could most distinctly see six , in some eight eyes , ranged in this order ; the innermost least , and the outermost greatest , of a very quick and lively transparency or fulgour , like eagle's eyes ; every eye hath a pale yellow circle , which encompasseth a violet-blew pupill , most clear and most admirable , but not perforated at all . letting her lye on the object-plate for half an hour together , we perceived her eyes all of them to grow less and less , and a whitish kind of film or socket , by degrees , to cover part of them : i cutt her in the midst at first , and so layd onely her head with the upper part of her body , on the object-plate . observat. x. the field spider with long legs . this spider was a very pleasant spectacle : having cutt off her legs , and layd her flat with her belly upon the object-plate , i perceived a round knob erected perpendicularly upon the top of her back , which proved to be her head ( though at first i could not perswade my self into that belief ; ) for in it were fixed two jett-black protuberant ( but not foraminulous ) eyes , on either side one , which by diligent inspection we found to be of different parts , with a very black smooth pupil in the midst of either of them , more protuberant than the rest of the circumambient matter , which was of a coarser grain , browner and more rugged than the prominent pupil . she had before , two claws ( at a manifest distance from her head ) just like a crab's claws , with two black tips , like the chely's in crabs , which i could distinctly see to open and shutt ( exactly like those in a scorpion ) which were indented , or made ▪ saw-wise on the inside ( the better to keep fast what she had once laid hold on . ) there is a field-spider of a russet colour and long legs , of the same shape and figure . the head and eyes in all spiders are contrived with great variety . observat. xi . another field-spider . i took a field-spider under a stone , . of june , with a bag of eggs fastned to her tayl , bigger than all the bulk of her body ; i opened it , and saw abundance of blewish eggs in it , which in the microscope look'd white and round , like your counterfeit pearl , and i could most clearly see abundance of very minute spiders , newly hatch'd , no bigger , and just like mites in meal , with white hairs and bristles , especially in their tail , creeping and crawling amongst the eggs : the nett-work of the purse or bag seem'd all diaphanous ; a very pleasant spectacle , and of curious workmanship . i then made the like observation of a bag full of house-spider-eggs , which are round and white , just like white poppy seed ; and all things look'd whitish , and something transparent therein also : but the youngling spiders ( that were either hatching , or newly hatch'd ) were far bigger then the former , and white as alablaster , but shap'd like the parent with five legs on each side ( without hairs or bristles ) and not by far so active as the other . i could not see any heart beat in any of them all . observat. xii . mites in cheese . they appeared some bigger , some less ; the biggest appeared equal to a nutmeg ; in shape they seem'd oval and obtus'd towards the tail : their colour resembled that of mother of pearl , or common pearl , and reflected the light of the sun in some one point , according to their various positions , as pearl doth : so that it seems they are sheath'd and crustaceous animals ( as scarabees and such like insects are . ) i could perfectly see the divisions of the head , neck , and body . to the small end of the oval body was fastned the head , very little in proportion to the body , its mouth like that of a mole , which it open'd and shutt ; when open'd , it appear'd red within : the eyes also , like two little dark spots , are discernable : near to the head were four legs fastned , two on each side ; the legs were just like to those in a louse , jemmar'd and transparent : she has two little pointers at the snout ; nay , you may see them sometimes , if you happily take the advantage , like so many ginny-pigs , munching and chewing the cud : about the head and tail are stuck long hairs or bristles : some we could see ( as little , even in the glass , as a mustard-seed ) yet perfectly shap'd and organiz'd : we also saw divers atoms somewhat transparent like eggs , both in form and figure . nay , in these moving atoms , i could not onely see the long bristles formerly specified , but also the very hairs which grew out of their leggs , which leggs themselves are smaller than the smallest hair our naked eyes can discover . what rare considerations might an ingenious speculator take up here , even from this singular experiment ? of the strange and most prodigious skilfulness of nature in the fabrick of so minute an animal ( a thousand whereof do not weigh one single grain , ( for one seed of tobacco is bigger than any of them ) and yet how many thousand parts of matter must go to make up this heterogeneous contexture ? for , besides the parts inservient to nutrition , sensation , and motion , how small and thin must the liquours be that circulate through the pipes and vessels disseminated through those parts ? nay , how incomprehensibly subtil must the animal-spirits be , that run to and fro in nerves included in such prodigiously little spindle-shank'd leggs ? observat. xiii . mites in malt-dust and oatmeal-dust . they seem somewhat different from those of cheese , formerly described , yet of the same bulk , proportion , and colour ; onely besett with more and longer white bristles , especially in the tail : they are far more active and quick in motion than those inhabitants of case-bobby , some bigger , some lesser . some we saw so exceeding little ( yet perfectly organiz'd and shap'd like the rest ) that no bristles nor hairs could be discern'd , either because they had none , or else ( more probably ) because the glass failed in presenting them : for how small must that hair be , think you , which ( though so excessively augmented in the glass ) yet seems as small as any hair imaginable ? and upon an animal too , whose whole bulk to the bare eye is quite indiscernable . if you besprinkle the object-plate , upon which you view them , with a pretty quantity of oatmeal , you shall see what working and tugging these poor little animals make amongst it , running and scudding amongst it ; under it , over it , and into it , like rabbits into their burrows ; and sometimes casting it and heaving it up , ( as moles or pioners do earth ) and trolling to and fro with this mealy dust ( which seems something diaphanous ) sticking to them , as if it were a little world of animals , busying themselves in running this way and that way , and over one anothers backs ; which is a spectacle very pleasant to behold . observat. xiv . mites , bred amongst figs. they are in colour like other mites , but bodyed and shaped like scarabees , with two little short horns at the snout , and above them two very long ones : you may clearly see three leggs on either side the body : they are more sluggish and unweildy then meal-mites are , and not bristled like them . though i have seen some amongst them also full of white bristles , and shaped like those in oatmeal : the like common ( for so i may call them ) mites i have also found in hay , in the powder that falls off dryed roots , &c. observat. xv. the mites , in jujubes and sebesten's . from jejub's and sebesten's , being long kept , there falls a brownish kind of powder , which being laid upon the object-plate , you shall discover in it small whitish mites , very little ones , and all besett with bristles and hairs round over like a hedghog , but not of so quick and lively a motion as the other mites . observat. xvi . the red mite , found on spiders . there is a red mite which you shall often find feeding upon spiders ; she is bodied just like a tortoise , with a little head and six long small leggs , three on each side : about the leggs of the field-spider i have found many of these coral-mites or tortoises , and this thing i have observed of them , that they cling exceeding close to the animal whilst she is alive ; but when dead , they all fall off and creep away from her , as lice do from dying men , or other vermin from an old rotten falling house . observat. xvii . the mites or lice found on humble-bees . within that yellow plush or furre of humble-bees you shall often find a little whitish very nimbly-running animal , which hath the shape and form of a mite in the microscope : i remember the industrious kircher sayes , he hath found by his glasses lice upon fleas : either our fleas in england are not like theirs in italy for this property , or else i have never taken them in their lowsie season : but i see no reason to the contrary , but both fleas and lice may have other lice that feed upon them , as they do upon us . for since the minutest animal that comes within the reach of our microscope , is found to have a mouth , stomack , and gutts , for nutrition ; and most , if not all , the parenchymata for circulation and separation of excrements , there can be no doubt , but they have also a continual perspiration and exudation through the habit of their body : of which excrement of the third and last concoction , all these vermin that pester the outside of animals , are generated . observat. xviii . pond . mites . there are bred in most restagnant waters , pools and fishponds , in june and july , an innumerable company of little whitish animals , which move up and down the water with jerks and stops in their motion ; in which animals we could discover two little horns and leggs , but could never get to see it quick in the microscope : for as soon as ever it is taken out of the water , it is perfectly dead . neither may it seem strange to find these animals in restagnant fish-waters , since the very ocean it self in some places ( in summer time ) is full of living creatures . for our western navigators tell us , that in summer , in the west-indian seas ( about the coasts of virginia , hispaniola , jaimaca , cuba , &c. the sea swarms with maggots and grubs , which in a little time will so eat their very ships ( as far as they draw water ) that lye there at anchor , that they will be as brittle and as full of holes as a honey-comb , or a grater ; insomuch that we are forced to have them cased either with thin sheets of lead , or with flax , pitch and tarr , to secure them from that danger . nay , not onely the water , but the very air it self , may certainly at some times and seasons be full of living creatures ; which must be , most probably , when great putrefactions reign therein , as in the plague-time especially . now it were well worth the observation , if in such aerial putrefactions any kind of living creatures could be discovered , which probably may be done by glasses : for i am sure in my long telescope i can some days see a tremulous motion and agitation of rowling fumes , and strong atoms in the air , which i cannot see of other days ; of which i shall perchance more largely discourse in my telescopical observations . observat. xix . whey-worms , call'd by some , wheal-worms , or hand-worms , or barrows . these smallest of creatures ( being accounted by muffet as a species and kind of mites , bred upon animals , as the former sort are in cheese , meal , wax , rotten wood , &c. ) may very well be the subject of our next observation . in this small animal you may see an oval reddish head , and therein a mouth or prominent snout , arm'd with an appendent proboscis or trunk , consisting of many villous filaments in figure of a cone , wherewith it perforates our skin , and sucks the blood or aqueous nutriment from the pustules it is bred near . nay , you may discover feet , laterally ranged on both sides , and many hairy tufts on the tayl , with asperities , rugosities , and protuberances in the skin . to behold all which varieties of parts and organs in so minute a particle of matter ( as this living atom is ) , i know not whether it be more admirable to behold , or incredible to believe without an ocular demonstration . certainly scaliger and muffet would have far more admired this almost invisible sub-cutaneous inhabitant , had they had the happiness to have seen it in our microscope . hear their description , taken onely by the opticks of nature , syronibus nulla expressa forma , praeterquam globi ; vix oculis capitur ; magnitudo est tam pusilla , ut non atomis constare ipsum sed unum esse ex atomis epicurus dixerit : ità sub cute habitat , ut , actis cuniculis , pruritum maximum loso ingenerat , praecipuè manibus : extractus acu , & super ungue positus , movet se , si solis etiam calore adjuvetur . mirum est quomode tam pusilla bestiola , nullis quasi pedibus insidens , tam longes sub cuticula sulcos peragat . our famous mayhern ( who had the advantage of an ordinary microscope ) gives this short , but very neat description of this poor animal . imò ipsi acari , ( saith he ) prae exiguitate indivisibiles , ex cuniculis prope aquae lacum , quos foderunt in cute , acu extracti & ungue impositi , caput rubrum , & pedes quibus gradiuntur , ad solem produnt . and therefore it is not to tell in what a small particle of matter , life may actually consist , and exercise all the functions too , both of vegetation , sensation , and motion : so that , omnia sunt animarum plena , may have more of truth in it , than he could either think or dream of that first pronounced it . observat. xx. the gloworm or glassworm . her eyes ( which are two small black points or specks of jett ) are pent-hous'd under the broad flat cap or plate which covers her head ; which obscure situation , together with their exceeding exiguity , make them undiscernable to common spectators . yet in the microscope they appear very fair , like black polish'd jett or marble , semi-globular , and all foraminulous , or full of small but very curious perforations ( as in common flyes . ) her two horns are all joynted and degree'd like the stops in the germination of some plants , as hors-tail and canes : under which she hath two other small horns or pointers , of the same stuff and fashion . take hold of her horns , and you may draw out her eyes and cut them out , and so lay them on your object-plate and see them distinctly . this is that night-animal with its lanthorn in its tail ; that creeping-star , which seems to outshine those of the firmament , and to outvye them too in this property especially ; that whereas the coelestial lights are quite obscured by the interposition of a small cloud , this terrestrial-star is more enliven'd and enkindled thereby , whose pleasant fulgour no darkness is able to eclipse . observat. xxi . common grasshoppers . in those common grasshoppers , both great and little , which are so frequent at hay-time with us , there are some things remarkable . first , their eyes , which like other insects are foraminulous ; nay , we have taken the cornea or outward film of the eye quite off , and clensed it so from all the pulpous matter which lay within it , that it was clear and diaphanous like a thin film of sliffe or muscovy-glass , and then looking again on it in the microscope , i could plainly see it foraminulous as before . you shall in all grasshoppers see a green film or plate ( like a corslet ) which goes over the neck and shoulders , which if you lift up with a pin , you may see their heart play , and beat very orderly for a long time together . the like curious lattice-work i have also observ'd in the crustaceous cornea of the creckets eye , which i have carefully separated from all the matter which stuff'd it within , which certainly is their brain ; as hereafter shall be made more probable . observat. xxii . the ant , emmet or pismire . this little animal is that great pattern of industry and frugality : to this schoolmaster did solomon send his sluggard , who in those virtues not onely excels all insects , but most men . other excellent observables there are in so small a fabrick : as the herculean strength of its body , that it is able to carry its triple weight and bulk : the agility of its limbs , that it runs so swiftly : the equality of its motion , that it trips so nimbly away without any saliency or leaping , without any fits or starts in its progression . her head is large and globular , with a prominent snout : her eye is of a very fair black colour , round , globular , and prominent , of the bigness of a pea , foraminulous and latticed like that of other insects : her mouth ( in which you may see something to move ) is arm'd with a pair of pincers , which move laterally , and are indented on the inside like a saw , by which she bites , and better holds her prey ; and you may often see them carry their white oblong eggs in them for better security . observat. xxiii . of the little greenish grasshopper or locust , bred upon the backside of green leaves , especially the leaves of goosberries , sweet-briar , and golden muosear , in april and beginning of may. this pretty animal is a pleasant object to look upon in our glass , being of a light green , and in the full sunshine shews exactly like green cloth of silver ; hath two horns and four leggs , two on each side : her eyes are two such very little black atoms , that , unless to a very critical and smart eye , they are indiscernable ; yet if you advantageously place her , and view her with a full light ( transmitted through a burning-glass ( which artifice i sometimes use ) you shall fairly see them to be as bigg as two small black round beads , and drill'd through also with innumerable perforations ( as the eye in a fly ) which will try the exquisiteness both of your glass and eye to behold . observat. xxiv . the yellow locust . there is a pretty , but very little , white oblong insect , which sticks to the ribs and backside of rose-tree-leaves in august , which in the microscope looks of a pure white colour , and diaphanous like sugar-candy , with an annular body like a wasp , with some e●ght hoops or rims , and conical or rush-grown towards the tayl , with six long legs , every leg composed of three joynts , all besett with short hairs , especially in the annulary divisions and interstices of her body : her eyes were very globular , protuberant , and large ( as they are in all young animals ) white , like two crystal beads , and most neatly lattic'd , which i could most clearly discern . below the eyes ( as she lay upon her belly ) was two crook'd horns , which bended backwards towards her tayl , and was fasten'd in two sockets at the roots ; and , as i thought , i sometimes see her eyes more protuberant than others , as if she could thrust them out , and draw them in at pleasure , as we have formerly observ'd in the wood-louse observ. she has two pair of bristles or hairs ( like mustacho's ) at the snout , one bending one way ; and another , another . i could discover no mouth , though i turn'd her over and over . this puny insect i have observ'd to turn into a small yellow locust , with two white wings longer than the body , and to skip up and down the rose-tree-leaves in august ; and then ( when she was metamorphos'd into a locust ) i could discern no mouth in the microscope , but onely two pointers like a pair of closed compasses in her snout , which cannot be seen on her till she be winged , and then laid on the object-plate with her belly upwards . observat. xxv . of cuckow-spitt , and the little insect bred therein , in may. that spumeous froth or dew ( which here in the north we call cuckow spittle , and , in the south , woodsear ; and which is most frequently found in lavander-beds , hors mint , &c. ) looks like a heap of glass-bubbles , or a knob'd drinking-glass ; in which you shall always find a little grub , or animal , which in the microscope seems a pretty golden-coloured insect , with three leggs on each side ; and two horns , and two round fair goggle-eyes of a duskish red colour , like polish'd rubies ; which you may also see latticed and perforated in a clear light . her tayl is all jemmar'd with annulary divisions , which at last end in a stump , which she often draws up , or thrusts out , at her pleasure . muffet cals this insect , locustellam , or , a puny-locust ; and saith , that first it creepeth , then leapeth , and at last flyeth . she has two blackish claws , or pounces ( at the ends of her feet , ) which she can open and shut at her pleasure : we could discover no mouth at all , but a long reddish probe , between the fore-legs , through which , perchance , she suck'd her froathy nourishment . now , what this spumeous matter is , and into what animal this insect is at last shaped or transpeciated , are doubts that as yet have found no clear and experimental decision . that the spattle is a froathy kind of dew that falls from the air , i doubt not , whatsoever my lord bacon say to the contrary . for , first ; it is found upon most , if not all , plants whatsoever , but most copiously amongst our whinns , or prickly broom ; and generally about the joynts and ramulous divisions , because there it is best secured from the heat of the sun , which licks it off the open leaves , or else probably it is imbibed by the full grown and porous leaves of plants , as the mill-dew , and other honey-dews are . secondly , that it is the sole exudation and secrement of plants , i cannot believe : first , because it is never found upon their second growth , nor in eddish : secondly , how should an excrement of so many several plants , still breed one and the same animal , when as we see that all vegetables whatsoever produce their several insects ( as muffet in his . and . chapters has particularly enumerated . ) i shall not deny but the effluvium's that continually perspire out of all plants whatsoever , may advantage and promote the nutrition of the little insect that breeds therein . for that all vegetables have a constant perspiration , the continual dispersion of their odour makes out ; besides an experimental eviction i shall give you by this singular experiment : . of feb. ( — . ) we weighed an onyon exactly to two ounces , two scruples and a half , and hanging it up till the . of may next following ( at which time it had sprouted out a long shoot ) we then , upon a re-ponderation of it , had lost near two drams of its former weight , which was exhaled by insensible transpiration . observat. xxvi . the cow-lady , or spotted scarabee . it is a very lively and nimble animal : cut off the head , and erect it perpendicular upon the neck ( which must be fasten'd to a bit of soft wax ) and then you shall see those two little small black eyes it hath , sett upon a little short neck ( which is moveable within the former ) either eye sett between three white plates , like polish'd ivory ( two little ones on the one side , and one great one on the other ) her eyes are also foraminulous , and curiously lattic'd like those in a fly formerly describ'd . if you unsheath her body , and take off her spotted short crustaceous wings , you shall find under them another pair of filmy tiffany long wings , like those of flyes , which lye folded up , and cased within the former , of both which pair she makes use in flying ; which being removed , nothing remains to secure the bulk of the body but a thin tender black skin , under which you might most lively see the pulsation of her heart for twelve or fourteen hours , after the head and neck was separated . observat. xxvii . the water-insect , or water-spider . there is a black crustaceous insect with an annular body , and six hairy legs , which moves nimbly upon the water ; the two foremost legs are shorter than the rest by one half , and serve instead of hands to reach any thing to the mouth : she hath two hairy geniculated horns , knotted or joynted at several divisions like knot-grass , or hors-tayl : her body is like frost-work in silver : her eyes black , globular , and foraminulous . observat. xxviii . the wasp-like locust . there is a little small long black insect , which you shall find creeping and leaping amongst pinks , gillyflours , rose-leaves , &c. which in the microscope hath two fair long wings , and is bodied just like a wasp ( from whence i have given her the name of the wasp-locust ) with six or seven annulary divisions , of jett-black and yellow wings : she hath two horns , made of five or six white and black internodium's , very pretty to behold ; either of them arising from a black knobb'd root , with three black legs on either side , and two little black eyes , and , as i ghessed , latticed ; though what art can present distinct parts in that eye which is sett in an animal so small , that the whole bulk of it is no bigger then a little bit of black thread , or hair . they are kill'd with the least touch imaginable . i took them with a pint point dipp'd in spattle , and so glew'd them to the object-plate , as i do stronger insects with a touch of turpentine . observat. xxix . the sycomore-locust . there is a pretty little yellow insect , which is bred , and feeds on the sycomore-leaves , which at first hath no wings , but six leggs and two horns , and runs nimbly up and down : in the glass , i could not onely see its eyes , which are red , globular , goggled and prominent ; but also i could see them very perfectly latticed . she had two horns , which at the ends were slit and bi-furcated : i could , near her shoulders , see the stumps of her growing wings : this at last is transpeciated into a fly with two long wings ; or rather a locust : it consists of annulary circles , and has hairs towards the tayl . observat. xxx . of the little white eels or snigs , in vineger or aleger . they appear like small silver-eels , or little snigs , and some of them as long as my little finger , constantly wrigling and swimming to and fro with a quick , smart , and restless motion . in which smallest of animals these things are most remarkable : first , they are not to be found in all sorts of vineger nor aleger , but onely in such , probably , as has arrived to some peculiar temper or putrefaction , of which i can give you no characteristical signs ; for , i have found them in all sorts of vineger , both in the keenest and smartest , as well as in the weakest and most watrish vineger ; and in all these sorts , you shall sometimes find none at all ; and i have both found them , and also vainly sought them , in the former liquors , at al seasons and times of the year also . secondly , the manner and best way of observing them is , upon a plain piece of white glass , whereon two or three drops of the said liquors are laid ; and so laying that glass on the object-plate , and fitting your microscope to it , you may distinctly see them to play and swim in those little ponds of vineger ( for so big every drop almost seems ) to the very brink and banks of their fluid element . thirdly , nay you may see them ( especially in old aleger ) with the bare eye , if you put a little of it into a clear venice-glass , especially into those pure thin white bubbles , which they call essence-glasses ; you may then see an infinite company of them swimming at the edges of the liquor , nay and in the body of it too , like so many shreds of the purest dutch thread , as if the whole liquor was nothing else but a great shoal or mass of quick eels or hair-worms . i have another advantageous way of discoverance of them to the bare eye also , which is by putting a little of those liquors into a little cylinder of white glass , of a small bore and length , either sealed or closed up with cork and wax at the one end : therein , if you invert this glass cylinder , and often turn it topsy turvy , no liquor will fall out , onely a little bubble of aire will always pass and repass through the inverted liquor , and one pretty thing i have herein observed , that when this bubble has stood in the superiour end of the glass ( and sometimes it would do so for a pretty while together before it broke ) i have seen some of those small snigs or animals on the top of it , crawling over the smooth convexity of the bubble ( like so many eels over a looking-glass ) without breaking thorow the tender cuticle and film of so brittle and thin a substance . fourthly , that as the liquor ( dropt upon your object-plate ) spends and dries up , so you shall see those little quicks to draw nearer and nearer together , and grow feebler in their motion ; and when all the vineger or aleger is dried away , then they lie all dead , twisted and complicated all together , like a knot of eels , and after a little time dry quite away to nothing . fifthly , their heads and tails are smaller then the rest of their bodies ; which is best observed by the microscope , when the liquor wherin they swim is almost spent and dried up , so that their motion thereby is rendred more feeble and weak , or when they lie absolutely dead . sixthly , another remarkable thing , is , their exceeding exiguity ; for certainly of all animals they are the least that can be seen by the bare eye , which is helped and advantaged also by the refraction of the water wherein they swim . seventhly , if you take a spoonful of the foresaid vineger and heat it over a few coals , it presently destroys all the quick's in it , so that you may see them all stretched out at their full length , like a pencil chopt small , or little bits of hairs swimming up and down the liquor , which in a short time will precipitate and all sink down to the bottom of the glass . nay these poor vermin are not onely slain by actual heat , but by a potential one also : for , putting but a few drops of the oyle of vitriol into an essence-glass full of that vineger , it also shortly destroyed them in the same manner as the fire had done before . eighthly , now though heat hath that killing property , yet it seems that cold hath not : for i have taken a jar-glass full of the said vineger , and by applying snow and salt to it , i have artificially frozen all the said liquor into a mass of ice , ( wherein all these animals it seemed lay incrystalled ) though i could discover none of them in it ( though i have taken the icy-mass out on purpose to look at it ) so that now i gave them for gone for ever : yet when i came again ( about two or three hours after ) to uncongeal the liquor , by keeping the glass in my warm hand , when the vineger was again returned to its former liquidity , all my little animals made their re-appearance , and danced and frisked about as lively as ever . nay i have exposed a jar-glass full of this vineger all night to a keen frost , and in the morning have thaw'd the ice again , and these little vermin have appeared again and endured again that strong and long conglaciation without any manifest injury done to them ; which is both a pretty and a strange experiment . ninthly , i have filled an essence-glass half with the said vineger , and half with oyle ( which floated on the vineger ) in a distinct region by it self , and i have observed that in frosty weather when the vineger has been congealed , that all the little eels have run up into the super-incumbent oyle to preserve themselves there , and would not return till some warmth was applyed to the vineger again , and then they would always presently return down into their native liquor again . tenthly , their motion is very remarkable , which is restless and constant , with perpetual undulations and wavings , like eels or snakes ; so that it seems , that animals that come nearest the classis of plants , have the most restless motions . eleventhly , the innumerable number and complicated motion of these minute animals in vineger , may very neatly illustrate the doctrine of the incomparable des-cartes , touching fluidity : ( viz. ) that the particles of all fluid bodies are in a continual and restless motion , and therein consists the true nature of fluidity : for by this ocular example , we see there may be an intestine restless motion in a liquor , notwithstanding that the unassisted eye can discover no such matter , which likewise is evinced by observ. . of the mites in meal . observat. xxxi . of the great black snail . in this slimy animal ( the slow-paced engine of nature ) are very many rare and excellent observables . the first is his eyes , which are four in number , ( like black atramentous spots ) fixed to the end of their horns ; or rather to the ends of those black filaments or optick nerves , which are sheathed in her horns which she can retract or protrude , through the hollow trunck of her horns , as she pleaseth . if with your finger you take hold of the tip of her horn when fully extended , and draw out this nervous filament , or then nimbly clip off the extremities of her horns , you shall in the microscope see those . black spots to be semi-spherical eyes , like two large blew beads : and we could afterwards also , when she re-extended the stump , clearly perceive it with the bare eye to be tubulous and hollow . and therefore however , though the learned doctor brown ( my ever honoured friend ) hath ranked this conceit of the eyes of a snail ( and especially their quadruplicity ) amongst the vulgar errours of the multitude ; yet through a good microscope , he may easily see his own errour , and nature's most admirable variety in the plurality , paucity , and anomalous situation of eyes , and the various fabrick and motion of that excellent organ ; as our observations will more particularly inform him . if by a dextrous dissection you would see the internal fabrick of this animal , there are many excellent things that will recompence your curiosity . for first , you may find her heart just over against that round hole near her neck ( which doctor harvey ingeniously conjectures to be the place of their respiration ; which hole you may observe to open and shut as she moves or stands still , and out of which i have observed some salivous matter to be evacuated . we have observ'd her heart to beat fairly for a quarter of an hour after her dissection ; afterwards we took out her guts which were of a pure green colour , by reason of the thinness of their film , and transparency of the green juice of hearbs with which they were repleated . they were all diaper'd or branched over with pure white capillary little veins , which ( by help of the microscope ) we could discern to be hollow , with a blackish kind of pith running through the midst of the smallest of them , which doubtless was their nutrimental juice coagulated there , like the bloud starkn'd in the veins of dead animals . they are mouthed like a hare or rabbit , with four or six needle-teeth , like those in leeches . nay this poor animal ( how contemptible soever it may seem ) hath a whole sett of the same parts and organs with other animals , as heart , liver , spleen , stomach , guts , mouth and teeth , veins and arteries : yea and a pair more of the noblest of the senses ( the eyes . ) nay this animal doth autoptically evince us , that , as sanguineous and more perfect animals , have a circulation of their bloud within them ; so this more ignoble creature hath also a circulation of its nutritive humour , which is to it as bloud is to other animals . nay further ( which is the best remarkable of all ) this juice hath not onely a circular motion ; but also the very animal spirits ( by which she moves ) seem to have the like circulation . for , if you observe her with the bare eye to creep up the sides of a glass , you shall see a little stream of clouds , channel up her belly from her tail to her head , which never return again the same way , but probably go backwards again from the head down the back to the tail ; and thus , so long as she is in local motion they retain their circulation , which is a pleasant spectacle . and more pleasant , if you let her creep upon the lower side of your glass-object-plate , and so view that wavy current of spirits through the microscope ; which handsome experiment does not onely prove the spirit 's circular motion , but also ocularly demonstrates that the animal spirits are the soul 's immediate instrument in all loco-motion . now if you reply that it is onely the parts of her body , that moving by a kind of undulation protrude one another forwards , as palmer-worms ( which we call wool-boys , ) and some sort of caterpillars do : to this i answer , that do but intensly observe any one of the former spots or clouds , and you shall see it go quite along from the tail to the head , keeping alwayes an equal distance from the precedent and subsequent spot : so that it is far more ingenious to believe it to be a gale of animal spirits , that , moving from her head along her back to her tail , and thence along her belly to her head again , is the cause of her progressive motion . observat. xxii . of lampreys . the lamprey hath seven holes or cavities , on eiside three or four , and no gills at all , as other fishes have ; whence the common people , through ignorance of these cavities , and their proper use in nature , have affirmed them to be eyes ; an errour so gross and palpable , that it needs not the microscope to refute it : for these holes or sluces do indeed supply the defect of gills , and are assisted by the conduit in the head , for ( like cetaceous animals ) the lamprey hath a fistula , spout or pipe , at the back part of the head , whereat they spirt out water , so that both these cavities and the head-pipe together , do very neatly supply the defect of gills , and execute their office of receiving and ejecting water again . these sluces and the fistula , shoot themselves slopewise , and not straight forwards , into the cavity of her neck . the heart in this animal is very strangely secured , & lies immured or capsulated in a cartilage , or grisly substance , which includes the heart and its auricle , as the scull or pericranium does the brains in other animals ; it is of a horny and transparent substance , of an obtuse conical figure , cemented and glewed as it were on all sides to the pleura , or innermost skin of the thorax ; the cone or obtuse tip of this capsula , butts or shoots it self into the basis of the liver , which to give way thereunto has an oval cavity or hollowness exactly fit to receive it . in this cartilaginous pericardium , or purse of the heart , is likewise the auricle co-included , lying not upon the basis of the heart as in other animals , but laterally adjacent thereunto , insomuch that it being far more flaggy then the heart , they seem to represent the right and left ventricle of the heart . yet is the heart , not onely more solid , but seated in the right side , and the auricle in the left . if the lamprey be laid upon her back , and you gently lift up with a probe , the heart and auricle ; you shall see a fine thin membrane arise , which separates the heart from the auricle , as the falx cerebri does separate the left side of the brain from the right . from this auricle proceeds a little short channel , which perforates this separating membrane , and brings the bloud from the auricle into the heart , we thrust a probe just under this channel betwixt the heart and the auricle , to see the bloud passe from the auricle into the heart ; for at every pulse of the auricle you might see the bloud passe through this channel into the heart ; for alwayes , as the bloud passed through it was blew , and , when empty , pale , and transparent , that i could easily see the probe thorow it . whilest i had the probe in this position , with another instrument and it together , i quite stopped the channel on purpose to hinder the bloud from coming into the heart , which thereupon grew very pale , and in a short time ceased its motion ; the auricle in the interim swelled and was very red . i no sooner opened the channel to let the bloud have a free passage as formerly , but the heart began afresh to beat again . we pricked the heart while it was in its motion with a large pin into the cavity thereof , and at every systole or contraction , we plainly saw a drop of bloud squeez'd and ejected out of that hole . in this animal , you may easily distinguish between the motion of the heart and auricle , for there intercedes the time of a pulse twixt the motion of the auricle and the heart ; and the heart in every diastole is of a fair purple and ruddy colour , and in every systole pale and wan , as is observable in frogs and other fishes also ; where you may see the heart to shift colours by turns , as it receives or ejects the bloud in the performance of the circulation . now the reason of this cartilaginous capsula of the heart in this creature , might be its defect of bones and those costal ribs , which serve others to secure the heart from all external violence ; for , she wanting these , had not nature wisely secured and capsulated the heart in this gristle , it had been subject to all external injuries , which might have hindred the motion , and endangered the life of the animal . this horny capsula , also served instead of a diaphragm to part the lower venter from the thorax . the lamprey likewise hath no bones : for the spine or back-bone , it hath a cartilaginous flexible tube or channel , without any vertebrae or spondyls in it , hollowed or tubulous from one end to the other ; in which lay the spinal marrow , which was of a serous , thin , and milky substance . in some lampreys , i have found the liver ( as doctor brown writes ) of a pure grass-green colour , which remain'd and kept that tincture whilst the animal lived ; but when i had cut it out of the body , and layd it by , it presently turned into a faint olive-colour . besides i have in the beginning of april cut up many lampreys , whose livers were of no such colour at all , but a dull yellow , like that of eels and other fishes . so that in this animal , and snakes also , you may distinctly see the bloud 's circulation . observat. xxxiii . corns of sand , sugar , and salt. it is worth an hour-glass of time to behold the crystal sands that measure it ; for they all seem like fragments of crystal , or alum , perfectly tralucent , of irregular polyhedrical figures , not any one globular ; every corn about the bigness of a nuttmeg , or a walnutt : which from their unequal superficies refracting and reflecting the suns rays , seem here and there of rainbow colours . being layd of a row or train , they seemed like a cawsy of crystal stones , or pure alum lumps : so that now we need not so much wonder with the vulgar philosophers , how so clear and glorious a body as glass , should be made of so durty , opace , and contemptible materials , as ashes and sand ; since now we are taught by this observation that sand , and salt which is in the ashes , the two prime materials thereof , are of themselves so clear and transparent , before they unite into that diaphanous composition . observat. xxxiv . a small atom of quick-silver . an atom of quick-silver ( no bigger then the smallest pins-head ) seemed like a globular looking-glass ) where ( as in a mirrour ) you might see all the circumambient bodies ; the very stancheons and panes in the glass-windows , did most clearly and distinctly appear in it : and whereas , in most other mettals , you may perceive holes , pores , and cavities ; yet in ☿ none at all are discoverable ; the smallest atom whereof , and such an one , as was to the bare eye , tantùm non invisibile , was presented as big as a rounseval-pea , and projecting a shade ; nay , two other atoms of ☿ , which were casually layd on the same plate , and were undiscernable to the bare eye , were fairly presented by our microscope . observat. xxxv . mercurial powders . in those chymical preparations of mercury , which they call turbith-mineral , mercurius vitae , dulcis , sublimate , precipitate , and mercury cosmetical , you may most plainly and distinctly see the globular atoms of current and quick ☿ ; besprinkled all amongst those powders , like so many little stars in the firmament : which shews that those chymical preparations , are not near so purely exalted and prepared , as they are presumed to be ; nor the mercury any way transmuted , but meerly by an atomical division rendred insensible . that subtle and pure yellow powder of mercury , called mercurius vitae , looked like the yolk of an egge boyled hard and crumbled to a gross powder : in it and in that meal-like powder of mercurius cosmeticus , were globules of ☿ plainly discernable . observat. xxxvi . of the seven terrestrial planets , as the chymists call them . viz. ☉ gold , ☽ silver , ♂ steele , ♀ copper , ☿ quick-silver , ♃ tin , ♄ lead . look at a polish'd piece of any of these metals and you shall see them all full of fissures , cavities , and asperities , and irregularities ; but least of all in lead , which is the closest and most compact solid body probably in the world . observat. xxxvii . ribbans of all sorts of colours , silk , satten , silver and mixed . in the silk ribbans , you might plainly see the contexture , how the warp and the weft cross one another at right angles ; and how neatly they are platted , just as in this picture : in satten ribbans , one warp crossed over three or four wefts , most lively and pleasant in cloth of silver , the weft ( being flat wired silver ) that crosses the warp , it makes a fine chequered representation . observat. xxxviii . the small dust , powder , or seeds of the lesser moon-wort . that small pure yellow meal or dust , which you may shake off from ripe moon-wort , appears like a heap of little white round bugles , or seed pearl , and something transparent when the sun shined , like to some other small seeds , with a fiber about every one of them like the semi-circular ribbe in a pompion : so that this experiment hath decided the old quarrel in herbalism , which is the least of seeds ; for though mustard-seed do carry the vogue amongst the people , yet its exiguity is to be respectively understood , of such seeds as extend to large productions ; for we see that the seeds of sweet marjerom and wild poppy , are far lesse ; and the seeds of tobacco so small that a thousand of them make not above one single grain in weight : yet must all give place to the super-exiguity of this farinaceous seed of wort , which is indeed 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . the exiguity and smalness whereof may very well be one of the magnolia of nature , somewhat illustrating the great work of the creation , and vast production from nothing . observat. xxxix . the seeds of wall-rue , or white maydenhair . take one of the leafs of wall-rue , ( which hath the blackish scurff sticking to the back side of it ) and lay it upon the object-plate , and you shall see all the seeds look just like a sett of black buttons upon green taffata ; and every button or seed compassed with a circle or ribbe , somewhat resembling a catterpillar : it hath been the opinion of old herbarists , that the capillary plants had no seeds , which errour did rise mee●ly from a popular inadvertency ; for though these plants carry not their seeds in , visible husks , pods , spikes , fruits , &c. yet are they constantly to be found on the back side of their leafs . observat. xl. of the seeds of strawberries . t is strange to see , what several wayes nature produceth and secureth the several seeds of plants ; some are preserved in large pulps , as the seeds of all pomiferous plants . others , besides the circum-involving pulpe , are immured in shells , as all stone-fruit , &c. others , in the lesser pulp of their berries , as mulberries , rasberries , &c. but in strawberries , nature hath put out the seeds , as if they were sproutings from the pulp : for those small specks or protuberances on the outside of the strawberry , are the seeds thereof , and in the microscope look not unlike the strawberry ; some reddish , yellowish , and green colours , as the strawberries themselves are . observat. xli . corn poppy seeds . they are none of them globular , nor of a smooth surface , but all like kidneys in form , and of the seeming bigness of walnuts , and like an hony-comb on the surface , with regular sides and angles , making all of them pentagonal and hexagonal areola's ; and glistering in the sun-shine like tissue , or the foil on the backside of a looking-glass , as is presented in these two figures . some other seeds also looked not unlike them , as henbane , flower of bristow , &c. observat. xlii . the small dust or powder on the pendents of lillies . in all our common garden-lillies ( especially the red and white ) out of the middle of the flower groweth a long style or poyntel , beset round about with small chives , which are tipped with pendents , a single pendent on the head of every chivall pounced over with a small dust or powder , which will cleave to and smut your fingers : this powder ( taken from the yellow lilly ) looks very pleasantly in the microscope , of a golden colour , and somewhat diaphanous : where you may see every atom very distinctly to be of an oval figure , exactly like some sort of seeds : the powder of the white lilly pendents , looks of a pure pale yellow , and like so many pieces of polished amber . observat. xliii . the leafs of several trees and plants . the backside of a rose-tree-leaf , but especially of a sweet brier leaf , looks diaper'd most excellently with silver . the backside of the leaf of english mercury , called bonus henricus , looks , as if rough-cast with silver , and all the ribs are stuck full of round white transparent balls , like innumerable grapes , or oake apples , or a bracelet of crystal ; and we could discover little foot-stalks in many of them , by which they were fastned to the ribs and fibers of the leaf , which is a very pleasant spectacle . a leaf of rue looks all full of holes like an hony-comb . a sage leaf looks like a white rugge , or shagge , full of knots , tassel'd all with white silver thrums , and one or two fine round crystal beads or pendents , as big as peas , fastned to every knot . observat. xliv . pink-pendents . the chives which grow out of red pinks , and which are tipped with red pendents , besmeared over with a small mealy powder , look very pleasantly in the glass ; for every pendent looks like a red taffata cushionet , all beset and sprinkled over with round white beads , or grumwel-seed . observat. xlv . of nettles . look at the backside of a nettle-leaf , and you shall see it all full of needles , or rather long sharp transparent pikes , and every needle hath a crystal pummel , so that it looks like a sword-cutler's shop , full of glittering drawn swords , tucks , and daggers ; so that here you may autoptically see the causes , as well as you have formerly felt the effects , of their netling . something like them , appear the prickles on borrage-leafs and stalks . observat. xlvi . gilla theophrasti . it looks pleasantly , like a diaphanous heap of icycles or stiriated niter ; but not altogether so regularly figured : but most of them are oblong particles , angular , and pointed , which may perchance exstimulate the stomach , ( by its netling pungency ) like a heap of needles , and so promote its vomitory operation . observat. xlvii . a nitt . a nitt is an egge glewed by some viscous matter to the sides of the hair it sticks to ; it is oval in shape , white in colour , and full of transparent liquor or gelly , and seems to be cased in a brittle shell by the crackling it makes 'twixt your nails . in the same manner appears a nitt in a horse's hair : muffet will needs have it a quick , or rudely-shaped animal . thus discursive argumentation and rational probabilities mislead men in the wilderness of enquiry ; but he that travels by the clew , which his own sense and ocular observation has spun out , is likeliest to trace the securest path , and go furthest into the maze and labyrinth of truth . observat. xlviii . a line drawn upon paper . as these dioptrical glasses , do heighten and illustrate the works of nature , so do they on the other side , disparage and depretiate those of art : for as they shew the incomparable exactness of the former , so do they discover the flaws and deficiencies of the latter ; for a right line either printed or drawn never so neatly upon paper appears all ragged , indented , and discontinued by the rugosities and seeming protuberances of the paper , in which likewise you may see whole clouds , as it were , of raggs , the primitive materials thereof . i had a rarity bestowed on me by master taylor ( once a famous scrivener in these parts ) which is , the lords prayer and creed writ in words at length , and a breviate also of the ten commandments , and all couched ( but distinctly writ ) in the compass of a single penny . in the microscope you might read it all , as if it were writ in text hand , but all the letters appeared ( as we have observed of the line ) crooked and unhandsome ; so inartificial is art when she is pinched and streitned in her workmanship . observat. xlix . the sparks of flint and steel . take a good steel and flint , and strike fire over a white sheet of paper , and observe diligently where some eminent spark falls ; for there you shall find a little dark spot or moat , no bigger then a pins point , which through our microscope did appear to be a perfectly round ball polished like steel or glass , insomuch that i could see the image of the window , and the motion of my hand reflected from it . what this polished atom is , master hook has ingeniously conjectured , viz. that it is a parcel of the flint or steel , or both ; which by so violent a percussion is made so glowing hot , that 't is melted into glass : for first , i observed that it was perfectly globular , and exactly like those glassy cindars , which are melted at the iron-forges . secondly , that it was none of the atoms of the steel or stone , grated off by collision ; for those you might easily see were distinguishable from it ; now that so little a stroak , and so small a fire can vitrify , will be better understood by him that knows , how small a heat at a lamp-furnace will melt glass : i have small capillary glass-tubes , which will melt immediately like wax , if you hold them but near the flame of a common candle , without any blast at all ; by which artifice i make small syphons , for the tryal of many notable experiments , of which i have treated at large in our mercurial experiments . this further i shall adde of flint , that in it you shall see small sparks of diamonds angular , and growing out of the stone as out of a mineral bed . observat. l. of hair. we slit a black horse's hair with a rasor , and perceived it to be hollow , with a white streak like pith in the middle of it ; it seemed as big as a rush , and like a rush slit length-wayes into two . they are none of them cylindrical , but angular and corner'd , which you may even perceive by your fingers , by twirling a horse-hair in them : now though borrelius , and some of our anatomists , as bartholin , riolan , &c. say the like of the hairs of a mans head , that they also are hollow within , and angular and corner'd without : yet i could never perceive neither the one nor the other in any of the microscopes i have seen , though i have tried it in four excellent ones , the worst whereof i am confident was better then that of borrels : in all which , i could perceive nothing of an hair , but that it was like a thin horn something diaphanous ( especially in the full sun ) which diaphanity might perchance hinder the appearance both of its cavity and angularity also : for i my self have little glass pipes of so little a cylinder , and so small a bore , that their hollowness to the bare eye is utterly imperceptible . and since the bristles and quils in other animals are sensibly hollow , which are analogous to the hairs in a man ; i doubt not , but every one of our hairs is hollow also , which though our glasses ( by reason of their transparency ) cannot present , yet it is palpably evinced by an odde experiment in poland , where there is a disease ( they call the plica ) which makes the very hairs of their heads drop bloud at the ends , and if cut any where , to drop bloud there also ; which infallibly proves the tubulous cavity of them . besides , we see the hairs do grain and fork themselves , ( when grown too long ) which is a sign also of their hollowness . what , shall we judge them too small to be perforated by nature ? since we see she has perforated vessels within the body , as small as hairs , as the venae lacteae , and lymphae-ducts ; nay , since we see that art can blow a glass hollow , and yet as small as hair ; and your wire-drawers know , that if they take a short piece of wire , as thick as a quill , and drill it through , that then though they draw it out to the smalness of a hair , yet wil it still remain hollow quite through in despite of their wurdle : which is as great a miracle in that engine , as that the like wire once gilt , shall remain perfectly gilt all over , though it be drawn five hundred yards longer than it was at first ; which is an experimental truth , and the dayly practice of our wire-drawers in london . so that the conclusion of this observation may be this , that every hair of our head is as a little quill or horn , hollow and transparent . which seems to be further avouched also by the burning of hair ; for there you may perceive the same odour and smell , as of burnt horn ; and the chymists , as i remember , draw out of hair a volatile spirit , exactly like that of harts-horn : both which experiments do prove an homogeneity and similarity of their substance . observat. li. of aromatical , electrical , and magnetical effluxions . some with a magisterial confidence do rant so high as to tell us , that there are glasses , which will represent not onely the aromatical and electrical effluxions of bodies , but even the subtile effluviums of the load-stone it self , whose exspirations ( saith doctor highmore ) some by the help of glasses have seen in the form of a mist to flow from the load-stone . this experiment indeed would be an incomparable eviction of the corporeity of magnetical effluviums , and sensibly decide the controversie 'twixt the peripatetick and atomical philosophers . but i am sure he had better eyes , or else better glasses , or both , then ever i saw , that performed so subtle an experiment : for the best glasses that ever i saw , would not represent to me , the evaporations of camphire ( which spends it self by continually effluviating its own component particles ; ) nay , i could never see the grosser steams that continually perspire out of our own bodies , which you see will foil and besmear a polished glass at any time ; and which are the fuliginous eructations of that internal fire , that constantly burns within us . indeed if our diopticks could attain to that curiosity as to grind us such glasses , as would present the effluviums of the magnet , we might hazard at last the discovery of spiritualities themselves : however it would be of incomparable use to our modern corpuscularian philosophers , who have banished qualities out of the list of the predicaments . and truly , as the learned doctor brown hath it ; the doctrine of effluxions , their penetrating natures , their invisible paths , and unsuspected effects , are very considerable : for ( besides the magnetical one of the earth ) several effusions there may be from divers other bodies , which invisibly act their parts at any time , and perhaps through any medium : a part of philosophy but yet in discovery ; and will , i fear , prove the last leaf to be turned over in the book of nature . some considerations , corollaries , and deductions , anatomical , physical , and optical , drawn from the former experiments and observations . first , therefore , it is ocularly manifest from the former observations , that , as perfect animals have an incessant motion of their heart , and circulation of their bloud ( first discovered by the illustrious doctor harvey ; ) so in these puny automata , and exsanguineous pieces of nature , there is the same pulsing organ , and circulation of their nutritive humour also : as is demonstrated by observ . fourth , sixth , seventeenth , &c. nay , by observ . sixth , it is plain that a louse is a sanguineous animal , and hath both an heart and auricles , the one manifestly preceding the pulse of the other ; and hath a purple liquor or bloud , which circulates in her ( as the noblest sort of animals have ) which though it be onely conspicuous in its greatest bulk , at the heart , yet certainly it is carried up and down in circulatory vessels ; which veins and arteries are so exceeding little , that both they and their liquor are insensible : for certainly , if we can at a lamp-furnace draw out such small capillary pipes of glass that the reddest liquor in the world shall not be seen in them ( which i have often tried and done ; ) how much more curiously can nature weave the vessels of the body ; nay , and bore them too with such a drill , as the art of man cannot excogitate : besides , we see , even in our own eyes , that the sanguineous vessels that run along the white of the eye ( nay and probably into the diaphanous humours also ) are not discernable , but when they are preter-naturally distended in an ophthalmia , and so grow turgent and conspicuous . to which we may adde , that in most quick fish , though you cut a piece of their flesh off , yet will no bloud be discernable , though they be sanguineous animals ; but the bloud is so divided by the minuteness of their capillary vessels , or percribration through the habit of the parts , that either it has lost its redness , or our eyes are not able to discover its tincture . secondly , it is observable also from the former experiments , that in these minute animals their nutritive liquor never arises to the perfection of bloud , but continually as it were remains chyle within them , for want of a higher heat to dye it into that spirituous liquor : nay , you shall observe in perfect sanguineous animals a circulation of an albugineous chylie-matter ( before the bloud have a being ) if you take nature at the rise , and critically observe her in her rudimental and obscure beginnings . for view but an egge , ( after the second day's incubation , and you shall see the cicatricula in the yolk , dilated to the breadth of a groat or six-pence into transparent concentrical circles ; in the centre whereof is a white spot , with small white threads , ( which in futurity proves the heart with its veins and arteries ) but at present both its motion and circulation is undiscernable to the bare eye , by reason of the feebleness thereof , and also because both the liquor and its vessels were concolour to the white of the eggs they swum in ; but the heart does circulate this serous diaphanous liquor , before ( by a higher heat ) it be turned into bloud . and one thing here i am tempted to annex , which is a pretty and beneficial observation of the microscope , and that is , that as soon as ever you can see this red pulsing particle appear ( which doctor harvey conceited , not to be the heart , but one of its auricles ) you shall most distinctly see it , to be the whole heart with both auricles and both ventricles , the one manifestly preceding the pulse of the other ( which two motions the bare eye judges to be synchronical ) and without any interloping perisystole at all : so admirable is every organ of this machine of ours framed , that every part within us is intirely made , when the whole organ seems too little to have any parts at all . thirdly , it is peculiarly remarkable from observation xxxi . that not onely the bloud in perfect animals , and the chyle in imperfect ones ; but also the animal spirits have a circulation , which singular observation hath often provoked and entised our endeavours into a further enquiry after the nature of these spirits , as to their origin or generation , their activity and motion , with some other eminent properties belonging to them : we shall draw our thoughts together , and so present them to your view : i will not say , that our discourse hereon , shall pass for an un-controllable authentick truth ; it is all my ambition if it attain but to the favourable reception of a rational hypothesis at last . a digression of the animal spirits . first , then , we have not those narrow conceptions of these subtle spirits to think that they are onely included within the bodies of animals , or generated ( much less created ) there , but we doe believe that they are universally diffused throughout all bodies in the world , and that nature at first created this aetherial substance or subtle particles , and diffused them throughout the universe , to give fermentation and concretion to minerals ; vegetation and maturation to plants ; life , sense , and motion to animals ; and indeed , to be the main ( though invisible ) agent in all natures three kingdoms mineral , vegetal , and animal . and lest they should ( because of their exceeding volatility and activity ) be of little or no use , nature hath immersed them in grosser matter , and imprisoned them in several bodies , with which she has intermixed them , the better to curb the boundless activity of so thin and spirituous a substance , and therefore the spirits ( of all compound bodies especially ) ought to be considered under a triple notion : viz. under the state of . fixation . . fusion . . volatilization . first of fixation , when they are so complicated with the grosser particles of matter , and lockt therein so fast , that they can hardly be separated , and dis-imprisoned as in minerals , but most especially in gold. secondly , the state of fusion , i call that , when the spirits by any kind of help have so wrought themselves towards a liberty , that they are in the middle way to volatility , as in half-concocted minerals , fermenting vapours or liquors , and half-ripned fruits , &c. thirdly , the spirits are in their third state of volatility , when after a colluctancy with the grosser particles they have so subjugated and overcome them , that they are just upon wings , and ready to fly away ; as in wine when it is in the height of its fermentation , and in some part of our arterial bloud alwayes . now we observe that those bodies that relax and open the grosser composition of other bodies , do presently create a fermentation ; for , being like so many keys , they set the imprisoned spirits at liberty , which presently fall on working , and by attenuating the grosser parts , separating the heterogeneous , volatilizing some , precipitating of others , digesting of others , expelling of others , do at last mould it and work it to such a body , as the parts of it are fit to make up : in all which interval of time , there is a palpable and sensible heat produced : thus this spirit being embowelled in the earth , and meeting there with convenient matter and adjuvant causes , doth proceed to produce minerals , creating an actual heat , wheresoever it operates , as in allum or copperase mines , which being broken , exposed , and moistned , will gather an actual heat , and produce much more of those minerals , then else the mine would yield , as agricola and thurniseer do affirm , and is proved by common experience . the like is generally observed in mines , as agricola , erastus , and ●ibanius , &c. do affirm and avouch out of the dayly experience of mineral men , who affirm , that in most places they find their mines so hot , as they can hardly touch them ; although it is likely that , where they work for perfect minerals , the heat which was in fermentation whilst they were yet in breeding , is now much abated , the mineral being grown to their perfection , as the skilful and excellent doctor jordan very well infers . the like heat we observe constantly to be in our cole-pits : nay , we sometimes observe in our brass-lumps ( as our colliers call them ) which is a kind of marcasite , a very great heat ; for being exposed to the moist air , or sprinkled with water , they will smoak and grow exceeding hot ; and if they be layd up on a heap and watered , they will turn into a glowing red hot fire , as i have seen them my self . and it was a casualty once terrible to our neighbour-town of ealand ; for there , one wilson a patient of mine , having pil'd up many cart-loads of these brass-lumps in a barn of his , ( for some secret purposes of his own ) the roof letting rain-water fall copiously in amongst them , they all began to smoak , and at last to take fire , and burnt like red hot coals ; so that the town was in an uproar about quenching of them ; and one thing further i took special notice of in this unlucky experiment , that the water which drained from the quenching of them , left little pieces and crystals of copperase sticking all along to the piles of grass , that grew in the croft it run down . thus antimony and sublimate being mixed together , will grow so hot ( the one relaxing the fermenting spirit in the other ) that they are not to be touched . thus in the corrosion of mettals by aqua fortis , what a strong heat is there in the liquor , and what a steam constantly evaporates during their fermentation . in the commixtion of oyl of vitriol with oyl of tartar per deliquium , what a violent heat and effervescence do presently arise , besides a sharp and acrimonious vapour that strikes our nostrils . nay , and we see our subterraneous damps do sometimes with intermixtion with the moist air , grow to that over-height of fermentation , that they fire of themselves and strike down all before them . thus the spirit of niter mixed with butter of antimony , grows so hot , that it is ready to rise in a flame . thus certainly do all baths receive their heat from mineral vapours , or the minerals themselves , being in solutis principiis , and so the fermenting spirit sets a playing in them , as the learned doctor jordan did most rationally conjecture . this universal fermenting spirit does not onely play these feats in the mineral ; but also operates in the same manner in the vegetable kingdome , which we ocularly behold in the artifice of malt , where the grains of barly being moistned with water , the parts are relaxed , the internal spirits in them are dilated , and put into action ; and the superfluity of water being removed ( which might choak it ) and the barly being layd up in heaps , the fermentation and heat presently appears , with a kind of vinous steam and effluviums which passe from it , and therefore it shoots forth into spires . thus we see in wet-hay , how the spirits work not onely to a heat , but ( if they be not cooled and prevented by ventilation ) they break out into a flame also ; nay , in all vegetables there is this constant heat ( though it be below our sensation ) as it is in some fishes and colder animals also , and a constant steam and transpiration of particles , as we have experimentally proved in our xxv . observation . and now let us pursue these spirits into the animal kingdom , and we shall see that they have the like effects and operations there also , as is formerly observed ; onely , being there in greater plenty , and more purely refined , and in a constant state of fusion and volatility , they work nobler effects . now the spirits that are lodged in all the meats and drinks we receive , being more or less fixed therein ; what does the soul , but ( like an excellent chymist ) in this internal laboratory of man , by a fermentation of our nourishment in the stomach and guts , a filtration thereof through the lacteae , a digestion in the heart , a circulation and rectification in the veins and arteries : what does she , i say , by these several physico-chymical operations , but strive all this while to unfix , exalt , and volatilize the spirits conteined in our nutriment , that so they may be transmitted to the brain , and its divarications , and in that reconditory kept and reposited for her use and service . so that these we now call animal spirits are the purest , subtlest , and most volatile particles and activest atoms of the bloud , which by continual pulsation of the heart are carried with the bloud by the carotidal arteries up into the brain , and there by that lax and boggy substance are imbibed and separated from the bloud , and thence by the spinal marrow and nerves transmitted to all the parts of the body . now as the chyle is perfected in the stomach and guts , and their appendent vessels , the lacteal veins ; and as the bloud is perfected in the heart , and it s annexed vessels , the veins and arteries : so the animal spirits are separated , preserved , and perfected in the brain , with its continued trunk and branches , viz. the spinal marrow , nerves , and fibers , for the uses hereafter to be declared . now the two former liquors , the chyle and the bloud ( because of their grosser liquidity ) need to be conveyed in hollow pipes and channels ( viz. the veins and arteries ; ) but the spirits which is the quintessence of them both , can easily pass by a swift filtration , through the brain , spinal marrow , and nerves , membranes , and fibers , which are as it were the cords , sayls , and tackling , to move this engine or vessel we call the body . nay , though we can give you no sensible eviction of it , why may not all those long filaments of which the substance of the brain , spinal marrow , and nerves consists , be tubulous and hollow ; so that the animal-spirits may be channelled through them , as the bloud through the veins and arteries ? i am sure , we see by observation xxxi . and l. what infinitely small filaments and vessels there are in animals , and yet all tubulous and perforated ; so that the suddain inflation of all those capillary threads or pipes , may serve for motion of the body , and the constant though flower filtration of the spirits through their coats and cylindrical membranes may serve for sensation . so that it seems , this cottage of clay , with all its furniture within it , was but made in subserviency to the animal spirits ; for the extraction , separation , and depuration of which , the whole body , and all the organs and utensils therein are but instrumentally contrived , and preparatorily designed . just as the chymical elaboratory with all its furnaces , crucibles , stills , retorts , cucurbits , matrats , bolt-heads , pelicans , &c. were made for no other end by the ingenious chymist , than for the extraction and depuration of his spirits and quintessences ( which he draws from those bodies he deals with ) in the obtainment of which he hath come to the ultimate design of his indeavours . now as in minerals and vegetables the colluctancy of these fermenting spirits with the grosser matter , does both create a constant heat and evaporation of atoms : so in animals , the like is more eminently conspicuous , to wit the vital heat , or calidum innatum , and those fuliginous effluviums which pass constantly out of us by insensible transpiration ; which sanctorius hath proved to exceed the bulk and weight of all our sensible evacuations whatsoever . having thus demonstrated how the soul obtains these spirits after her several operations of digestion , chylification , sanguification , circulation , &c. the like now let us see what use she makes of so pretious a substance . first , therefore we affirm , that this thin and spirituous matter , which is called the animal spirits , is the immediate instrument of the soul , in all her operations both of sense and motion . first , for sense , it is plain by what is discovered in a vertigo ; for the brain it self is not of such a fluid substance , as to turn round , and make all objects to do so too ; wherefore t is a sign that the immediate corporeal instrument of conveying the images of things , is the spirits in the brain . secondly , that they are the chief engine of sight , is plain ; not onely because the eye is full of these livid spirits , but also because dimness of sight comes from deficiency of them , though the parts of the eye otherwayes be entire enough , as in sick and old persons , and in those troubled with an amaurosis , or gutta serena . i had the last year a patient , a young boy of seventeen years old , who fell casually stark blind of his right eye ; in which you could outwardly discover no fault at all ( the disease being an amaurosis , or obstruction of the optick nerve ) for , that nerve being by successful means disobstructed and relaxed , so that the animal spirits were able to flow done to the retina again , he shortly after perfectly recovered his sight again , without any relapse at all , to this present day . thirdly , if you cast a ligature upon any nerve , you destroy both the sense and motion of that part whither that nerve was propagated ( as by that pleasant experiment by tying the recurrent nerves in a living dogg , we have tryed ) till by relaxing the ligature the spirits may have the freedome to channel into the nerves again : which truth is also handsomely made out , by that ordinary example of a mans leg being asleep ( as we call it ) for by compression of the nerves , the propagation of the spirits into the part is hindred ; for , as sense and motion is restored , you may feel something creep into the leg , tingling and stinging like pismires ( as spigelius compares it ) which is the return of the animal spirits into that part again . fourthly , that spontaneous motion is performed by continuation of the animal spirits , from the common sensorium to the muscle , ( which is the gross engine of motion ) is sensibly evinced in dead palsies , where one side is taken away . to all which add , the former observation of the spirits circumundulation when the snail at any time moved , and of their joint quiescency together . having now shown you how these animal spirits are generated in our body , or , to speak more properly , disimprisoned and separated from our nutriment , and so from fixation , brought through fusion to volatilization ; having also shown you what use nature makes of them in sensation and motion : let us screw our enquiry a little further , and see if we can discover how the spirits move in the brain and nerves , to perform the same operations . first , therefore , we affirm that a lesser quantity and slower motion of the spirits is required for sensation , than there is for motion ; for in this the muscle swells that moves the part , which is a plain indication of a greater influx of spirits directed thither ; a greater , i say , for i do not deny but there is required to sensation a moderate quantity and diffusion of the spirits into all the parts of the body , else we should alwayes be benummed and stupid ( as when our leg is asleep ) by an interception of the spirits . secondly , that their motion is slower in sensation then motion ; the former experiment of the snail does also manifest : whose animal spirits never begin to undulate till she begin to move , whereas she is sensible when they are in quiescency , as you may , by pricking her with a needle , easily observe . thirdly , in the return of the spirits into the stupefied leg , we plainly perceive by the prickling , what a flow motion the spirits have . all which phaenomena do seem to favour our former conjecture , that for motion the spirits move impetuously down the nervous filaments , ( which are hollow ; ) but for sensation they onely creep by a filtration down their coats and membranes . now these spirits being so subtle and dissipable , the soul spends them every day in using of them , and they being much spent , she can hardly move the body any longer : the sense whereof we call lassitude ; for certainly , as doctor more very ingeniously inferrs , if it were an immediate faculty of the soul to contribute motion to any matter ; i do not understand ( that faculty never failing nor diminishing , no more than the soul it self can fail or diminish ) that we should ever be weary . thus are the phaenomena of sense and motion best salved , whilst we are awake ; now what happens when we sleep , is a matter of further enquiry : some have defined sleep to be a migration of all the spirits out of the brain , into the exteriour parts of the body ; whereas by our former observations , it may rather seem to the contrary ; that is , the retraction of the spirits into the brain , or at least a restagnation of them in the nervous parts , does ( till nature being recruited by a new supply and regeneration of them in the brain ) direct them into the spinal marrow and nerves , which being replenished with them again , they run their current as before ; so the whole animal thereby is made capable of feeling the impulses of any external object whatever ( which we call , walking ) and during this interval and non-tearm of sensation ( for so we may without a complement call sleep ) why may not the soul be retracted , and wholly intent upon , and busied about , her vegetative and plastical operations ? so that when she has locked up the doors of this laboratory the body , she may be busie in augmenting , repairing , and regenerating all the organs and utensils within , and painting and plaistring the walls without . this i am sure we observe to be the greatest part of her obscure employment in the womb , where the embryo for the most part sleeps , whilst the soul is in full exercise of her plastick and organo-poïetical faculty . now these animal spirits being continually transmitted from the brain , through the spinal marrow , nerves , tendons , & fibers , into all the parts of the body ( especially whilst we are awaking ) may , some of them at least , have a kind of circulation ; for those which perspire not , having lost their motion , may either mix with the bloud in habitu partium , or relapse into a kind of insipid phlegm , as chymical spirits do , that are not purely rectified , and to be returned back by the lymphiducts again . lastly , i have but one paradoxical and extravagant quaere to make , and that is this ; that since we have proved these animal spirits to be the ultimate result of all the concoctions of the body , the very top and perfection of all nature's operations , the purest and most aetherial particles of all bodies in the world whatsoever , ( and so consequently of nearest alliance to spiritualities ) and the sole and immediate instrument of all the soul's operations here , even in statu conjuncto ( the body and the organs thereof , being but secondary and subservient instruments to the spirits : ) these things being thus premised , may it not be probable enough that these spirits in the other world , shall onely be the soul's vehicle and habit , and indeed really that 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , mentioned by the apostle ; by a vital re-union with which , it may supereminently out-act all that ever she was able to do in this earthly prison and heavy cottage of the body ; since also ( which i may super-adde ) those volatile spirits ( being freed by a constant and perpetual dissipation from the body ) are diffused through this great aetherial ocean , as into their proper element , ready to be united to the soul at the instant of her separation . fourth deduction . fourthly , the physiologist also may gather something from the former observations , touching the nature of colours ; that they are indeed nothing but the various modification of light. for most , if not all , bodies in their minute particles ( through which the sun's rays have more freedome to penetrate ) seem to lose their colours , and grow diaphanous , as you may observe in the microscope . secondly , is it not shrewdly probable , that since motion is the cause of sight , ( which is nothing else , but the impulse that the luminous atoms make upon the retina : ) is it not , i say , shrewdly probable , that colours are nothing else but a various modification of this motion , since we see that they are both naturally and artificially made by light , to which we can imagine nothing to be added or deducted to super-induce those fine tinctures as in the rain-bow , the prisme , crystal pendents , glass-globes filled full of water , and in those arenulous atoms in the former experiment xxxiii . except some change in the motion of the luminous atoms , which must necessarily follow from the diversities of objects and mediums they either hit upon or pass thorow ; and so consequently do either accelerate or retardate the solary atoms in their dinetical and progressive motion ; whence arises both the diversity and variety of all colours whatsoever , as that profoundest master of mechanicks ( des-cartes ) hath both subtilly excogitated , and ingeniously illustrated by the prisme . to which we shall add some further experimental eviction : first , if the hole ( through which the species is transmitted into a dark room ) be covered with a leaf of beaten gold , it will not onely look of a pure green colour , but all the light trajected through it will put on the same tincture . secondly , if with a prisme you strike the rainbow-colours upon a wall , and observing where a red is projected , you there place an eye , the spectator shall judge it to be another colour ; because that the solary atoms , which shot through the prisme upon the wall , and there painted that colour , being again and again refracted by the diaphanous humours of the eye , must needs , in all reason , exchange their motion , and so consequently paint the retina with another colour : both which experiments shew , that colour is nothing else but the modification of light , which by the alteration of its motion is dyed into colours . the like artificial alteration of the colours may be made by interposing a burning-glass 'twixt the prisme and the light , and 'twixt the prisme and the paper . but this cartesian theory of colours we shall further make out by several experiments in the extraction , commixtion , and transcoloration of tinctures . first therefore , if into the infusion of violets you put some few drops of the oyl of tartar per deliquium , it will presently strike it into a green tincture : now , if instead of that oyl you put in oyl of vitriol , it strikes it into a purple colour : to which if you super-add some drops of spirit of harts-horn , it strikes it green again . secondly , if into the tincture of dryed roses ( drawn in hot-water with oyl of vitriol after the usual manner ) you drop a few drops of spirit of harts-horn , or of urine , or of oyl of tartar per deliquium , it will presently strike the red into a green colour ; which by a super-addition of the oyl of vitriol , you may re-tincture as before . thirdly , if into an infusion of copperose you shave a little gall , it presently puts on a sable inky colour ; into which if you put a few drops of the spirit or oyl of vitriol , it strikes out the colour immediately , and the water becomes white again ; to which if you super-add a few drops of oyl of tartar per deliquium , it re-denigrates it again . thus a glass of the sweet-spaw-water also , upon the infusion of gall , turns into a claret-colour : but if you drop but a little of the said oyl or spirit into it , it presently eats out the colour , and the water returns to its primitive clearness again . draw a faint tincture of brasil wood , bruised or rasped in luke-warm water , filter it , and clarifie it ; then if you add a little sharp vineger to a good quantity of it , it will strike it into the exact colour of good stale english beer , and it will partly have the smell of it also . secondly , if into another quantity of the said reddish infusion you add a few drops of the oyl of tartar per deliquium , it will turn it to a pure purplish red , like excellent claret . thirdly , if into this artificial claret you drop a few drops of the oyl of vitriol , it will turn it into a pale amber colour ( like sack as may be ) which with addition of fair water you may empale as you please . by which ingenious commixtion of spirits and liquors did floram marchand , that famous water-drinker , exhibit those rare tricks and curiosity's at london , of vomiting all kind of liquors at his mouth . for , first ; before he mounts the stage , he alwayes drinks in his private chamber , fasting , a gill of the decoction of brasil ; then making his appearance , he presents you with a pail full of luke-warm water , and twelve or thirteen glasses , some washed in vineger , others with oyl of tartar , and oyl of vitriol ; then he drinks four and twenty glasses of the water , and carefully taking up the glasse which was washed with oyl of tartar , he vomits a reddish liquor into it , which presently is brightned up and ting'd into perfect and lovely claret . after this first assay , he drinks six or seven glasses more ( the better to provoke his vomiting ) as also the more to dilute and empale the brasil decoction within him , and then he takes a glass rinsed in vineger , and vomits it full , which instantly , by its acidity is transcoloured into english beer ; and vomiting also at the same time into another glass ( which he washes in fair water ) he presents the spectators with a glass of paler claret , or burgundian wine ; then drinking again as before , he picks out the glass washed with oyl of vitriol , and vomiting a faint brasil-water into it , it presently appears to be sack ; and perchance if he wash'd the one half of the glass with spirit of sack , it would have a faint odour and flavour of that wine also . he then begins his carouse again , and drinking fifteen or sixteen glasses , till he has almost extinguished the strength and tincture of his brasil water , he then vomits into a vineger-glass again , and that presents white wine . at the next disgorgement ( when his stomack is full of nothing but clear water indeed ( which he has fill'd so , by the exceeding quantity of water which at every interval he drinks ) he then deludes the spectators by vomiting rose water , angelica water , and cinamon water into those glasses which have been formerly washed with those spirits . and thus was that famous cheat perform'd , and indeed acted with such a port and flowing grace , by that italian bravado , that he did not onely strike an admiration into vulgar heads , and common spectators , but even into the judicious and more knowing part of men , who could not readily find out the ingenuity of his knavery . the chymical elaboratories likewise do teach us this truth in fumes and smoaks , as well as liquors ( which indeed are but rarified and expaused liquors ; ) for niter it self , though nothing a kin to redness doth in distillation yield bloud-red fumes ( called by the chymists salamanders-bloud ) which fall again into a liquor which hath nothing of red in it . so soot ( though black ) yet when it is pressed and forced up into an exhalation by a strong fire , will fill the receiver with milk white fumes ; thus sall-armoniack , and black antimony , being equally mixed and gradually sublimed in an urinal , will exhibit a scene of colours , and will make a transition out of one into another with a delectable variety . by all which pleasant observations , it palpably appears that the nature of colours consists in the free admission , transition , refraction , or reflection of light , from the objects discoloured ; for first , you see several colours introduced into liquors by those ingredients , that neither had nor could communicate any such tincture . secondly , 't is as plain , that the minute particles and atoms of those bodies that were imbibed by the liquors , and filled up their smallest cavities or interstices , accordingly as they were altered in their site , position , and motion ; so were the luminous beams variously transmitted , refracted , or reflected , and so consequently thence resulted those several scenes of colours . thus when the atoms wherewith the liquor is fully impregnated do relax and open themselves , that the light may fairly penetrate , then is the liquor limpid and clear ; but if they draw up a little closer one to another , so that the light be refracted , then is the liquor yellow ; if closer yet to a greater refraction of the light , then is the liquor red : but if in this randezvouz they draw up into a very close body indeed , so that by reason of their contiguity , both in rank and file , no light can be trajected through them ; then opacity and darkness arises : if the rays cannot break the front of them , then is a milky-whiteness presented there . the fifth corollary ▪ anatomical considerations about the eye . our next reflections shall be made upon the eye , to admire as well as contemplate nature's variety in the constructure and conformation of so excellent an organ : the two luminaries of our microcosm , which see all other things , cannot see themselves , nor discover the excellencies of their own fabrick : nature , that excellent mistress of the opticks , seems to have run through all the conick sections , in shaping and figuring its parts ; and dioptrical artists have almost ground both their brain and tools in pieces , to find out the arches and convexities of its prime parts , and are yet at a loss , to find their true figurations , whereby to advance the fabrick of their telescopes and microscopes : which practical part of opticks is but yet in the rise ; but if it run on as successfully as it has begun , our posterity may come by glasses to out-see the sun , and discover bodies in the remote universe , that lie in vortexes , beyond the reach of the great luminary . at present let us be content with what our microscope demonstrates ; and the former observations , i am sure , will give all ingenious persons great occasion , both to admire nature's anomaly in the fabrick , as well as in the number of eyes , which she has given to several animals : we see the tunica cornea in most insects is full of perforations , as if it were a tunica vvea pinked full of holes , and whereas perfect animals , have but one aperture , these insects have a thousand pupils , and so see a hemisphere at once : and indeed 't is worth our consideration to think , that since their eye is perfectly fixed , and can move no wayes ; it was requisite to lattice that window , and supply the defect of its motion , with the multiplicity of its apertures , that so they might see at once what we can but do at several times , our eyes having the liberty and advantage to move every way ( like balls in sockets ) which theirs have not . secondly , we observe no diaphanous parts in those lattic'd eyes , since it is probable , that the horney coat of the eye serves also for a pericranium for their brain : for , that the brain of most insects lies in their eyes , seems to me more than a probability . first , because in flies , butter-flies , bees , &c. you can find no other place in their heads , wherein any matter analogous to the brain , can be lodged . secondly , in the eyes of those insects you shall alwayes find great store of a pulpous substance , like to be brain in those creatures . thirdly , the eyes in all insects are very large , and seem disproportional to so small bodies , if intended for no other use than vision . fourthly , why may not this lattic'd film of their eye be their tunica retina , which as it is concave in us , is convex in them ; and as it is made of the brain in us , so it is in them , and therefore lies contiguous to it , and may indeed be over-cast , by a transparent cornea , through which the net-work of this interiour film may thus eminently appear ; for certainly such animals as have distinction of senses , as seeing , feeling , &c. must needs have an animal-sensation ; an animal , i say , for i hold also a natural sensation , which is performed without a brain , and such an one is discoverable even in animals , and in our own selves ; for besides the animal-sensation ( whose original is in the brain ) the stomach , guts , and the parenchymata of the body , yea and the bloud too has a natural sensation of what is good , and what is bad for them , as doctour harvey has excellently proved , lib. de gener. and so some of the lowest rank of animals ( as the zoophyta and plant-animals ) may perchance be utterly devoid of animal , and have onely a natural sensation ; but this belongeth to some anatomical observations i have by me , where i may perchance prove that all vegetables ( as well as the sensitive and humble plants ) have this latter kind of sensation , as well as animals . but let us return to the eye again , of which curious organ i am tempted to say much more ; but that i have reserved that discourse as more proper for my telescopical observations . onely for the present , to encourage the lovers of free philosophy , and to let them see that even the greatest oculists and dioptrical writers , that the world ever saw , kepler , des-cartes , schemar , and hugenius , have not yet discovered all nature's curiosities , even in that organ ; i will here deliver one or two optical experiments : the first hints whereof , i must ingeniously confess , i received from some fragments and papers of our famous , and never to be forgotten country-man , master gascoign of midleton near leeds , who was unfortunately slain in the royal service for his late majesty ; a person he was of those strong parts and hopes , that not onely we , but the whole world of learning suffered in the loss of him . take a fresh eye , and , in a frosty evening , place it with the pupil upwards , where it may be frozen through , then in the morning you may cut it as you please . if you cut it with a plain parallel to the optick axis ( which section des-cartes thought impossible ) then shall you see all the parts , as he has pictured them pag. . and each part will be very different in colour , and remain in their natural site , which may be pricked forth in an oyled paper : by this trick also you shall find , that there is a double crystalline humour , one circum-included within the other ; if you do but thaw the crystalline you shall see the outward will pill off from the inward : the right figures of both which crystallines are monstrous difficult , if not impossible , to find out ; hence it follows that every ray of incidence is seven times refracted in the eye before it reach the retina , whatsoever scheinar says to the contrary . the second experiment , is one of the ingenious excogitations of m. gascoign's , and it is to delineate the prime parts of the eye ; after this manner : having a glass and table fitted to observe the eye's spots , place an eye with the horny tunicle either upwards or downwards , between the inmost glass and table ; so near the glass , as the eye will almost fill up the compass of the eye's image , then the representation of the eye will be very large ( proportionable to the eye's image ) upon the table , and thus you may prick out the three figures of the cornea , and the outward and inward crystallines . many other neat wayes with my dioptrical glasses can i take the figures of the prime parts of the eye , which shall be discovered in their fit places . and now having done with the fabrick , the observations lead us to the consideration of the number and plurality of eyes , that nature hath afforded some creatures . i must confess though i have been very curious and critical in observing ; yet i could never find any animal that was monocular , nor any that had a multiplicity of eyes , except spiders , which indeed are so fair and palpable that they are clearly to be seen by any man that wants not his own . and though argus has been held as prodigious a fiction as polypheme , and a plurality of eyes in any creature , as great a piece of monstrosity , as onely a single one ; yet our glasses have refuted this errour ( as observat. viii . and ix . will tell you : ) so that the works of nature are various , and the several wayes , and manifold organization of the body , inscrutable ; so that we had need of all the advantages that art can give us , to discover the more mysterious works of that divine architectress ; but especially , when she draws her self into so narrow a shop , and works in the retiring room of so minute an animal . lastly , many more hints might be taken from the former observations , to make good the atomical hypothesis ; which i am confident will receive from the microscope some further advantage and illustration , not onely as to its first universal matter , atoms ; but also , as to the necessary attributes , or essential properties of them , as motion , figure , magnitude , order , and disposition of them in several concretes of the world ; especially if our microscopes arise to any higher perfection : and if we can but , by any artificial helps , get but a glimpse of the smallest truth , it is not to tell what a fabrick of philosophy may be raised from it ; ( for to conclude with that patriark of experimental philosophy , the learned lord bacon , ) the eye of the understanding , saith he , is like the eye of the sense ; for as you may see great objects through small cranies or levels ; so you may see great axioms of nature , through small and contemptible instances and experiments . these are the few experiments that my time and glass hath as yet afforded me an opportunity to make , which i hasten out into the world to stay the longing thereof ; but you may expect shortly from doctor wren , and master hooke , two ingenious members of the royal society at gresham , the cuts and pictures drawn at large , and to the very life of these and other microscopical representations . the end of the microscopical observations . experimental philosophy , in three books . containing new experiments microscopical , mercurial , magnetical . with some deductions and probable hypotheses raised from them , in avouchment and illustration of the now famous atomical hypothesis . by henry power , d r. of physick . london , printed in the year . liber secundus . mercuriall experiments . begun anno domini . by henry power , m ae . d r. itaque sperandum omnino est , esse adhuc in naturae sinu , multa excellentis usus recondita ; quae nullam cum jam inventis cognationem habent , aut parallelismum , sed omnino sita sunt extra vias phantasiae , quae tamen adhuc inventa non sunt , quae proculdubio , per multos saeculorum circuitus & ambages , & ipsa quandoque prodibunt . fr. verulam , lib. . novi organi , sect . . the second book . these physico-mechanical experiments are of four sorts , hydrargyral , hydraulical , pneumatical , and mixt. such things as are requisite for the triall of these experiments , are . a quart at least of ( ☿ ) quicksilver . . several glass-trunks , or cylindrical glass-tubes , some open at both ends , and some exactly closed ; or ( as they phrase it ) hermetically sealed at the one end . all of several lengths and bores . . a glass-tunnel or two , with wooden dishes and spoons , for filling of the glass-tubes with mercury . . you must have no metalline vtensils about you , for fear they be spoiled with the mercury . . spread a blanket or carpet on the ground when you try these experiments , that so none of the mercury may be lost , but may be taken up again with wooden spoons . . you may have by you also glass-syphons , weather-glasses of several right and crooked shapes , &c. the more to advantage the experiments . mercurial experiments . chap. i. experiment . take a glass-tube of above inches in length , as ab , closed at the end b , and open at a : fill it full of quicksilver , and so close the end a , exactly with the thumb ( as with a stoppel ; ) then reverse it , and putting it and your finger together into the wooden vessel d , fill'd about two inches deep with quicksilver , erect it perpendicularly therein ; then drawing away your finger from the orifice , your shall see a great part of the quicksilver in the tube to make a quick and smart descent into the external quicksilver in the vessel ; and after it hath , by several vibrations up and down , found out a certain point or degree , there to stand still and immoveable : so that all the upper part of the tube ( which the mercury has deserted ) viz. from e to b , will seem to be a vacuity . the first inventor of this noble experiment , was torricellius the eminent mathematician , and deserved successour to the famous gallilaeo , to whom all the common-wealth of learning are exceedingly oblieg'd , because thereby he has excited the greatest modern wits to higher and nobler experiments . in this torricellian experiment ( for so we shall alwayes hereafter call it ) let me give you notice of these rare observables : . if the tube be not longer then . inches , the quicksilver will not at all descend : this we have tryed in several tubes of , , and ½ inches long . . in tubes of a greater length then . inches , the quicksilver will descend . . the quicksilver will not descend lower then . inches , or thereabouts ; that is , the cylinder of mercury in the tube will alwayes be . inches in height above the superficies of the restagnant mercury in the vessel . . the quicksilver descends neither more nor less in tubes of a greater or lesser bore , provided they exceed the length of . inches . . how long soever the tube be , the quicksilver will fall down to its wonted pitch and stint of . inches or thereabouts ; as we have tryed in tubes of , ½ , , , and inches in longitude , and all of different diameters and bores . . if you add any more quicksilver to that in the vessel , then , that in the tube rises proportionally the higher : and contrariwise , if you take any quicksilver out of the vessel , that in the tube descends lower ; and so consequently , the internal quicksilver in the tube keeps alwayes the same height of that in the vessel . . that you may with great facility move the tube to and fro in the vessel'd quicksilver , but not draw it up towards the superficies of the external quicksilver in the vessel without some reluctancy . . that if you tilt or incline the glass-tube , you shall see the quicksilver gradually to ascend till it almost totally fill the tube , at which angle of inclination the atletus or perpendicular will be equal to . inches , let the tube be of what length soever . . that upon removal of your finger from the orifice , you shall see the quicksilver to make a very quick and smart descent six inches at least below the standard of its altitude in the glass of . inches long , and in others more or less ; and after a few vibrations up and down , to settle at its wonted pitch and altitude of . inches , or thereabouts . . that if any thing , considerably hot or cold , be applyed to the superiour part of the tube , the quicksilver therein will more or less ascend or descend , as the water in a weather-glass , though with farr feebler and more insensible effects : so that any time of the year it will not much desert nor surmount the determinate height and pitch aforesaid of . inches . . that this seeming vacuity in the tube would be judged by any one that came in at an adventure , to be nothing but such like illuminated ayr as this we breathe in . . if you dip your thumb into the vessel'd mercury , and close the orifice of the tube therin , and so gently reverse it , you shal see the quicksilver in the tube to move more swiftly ( though not without resistance , and ebullitions ) through that seeming vacuity ; and the mercury will pass with such shoggs towards the depressed extreme of the tube , as will make you apprehend that the tube will be either beaten out of your hand or broken : none of which phaenomena will appear , if you let in the outward ayr into the cavity unpossessed by the mercury . in which interim of motion , your thumb will be drawn and suck'd into the orifice of the tube , not without some considerable pain . . if before the removal of your thumb you reimmerge it again into the vessel'd quicksilver as before , & then draw the tube perpendicularly quite out of the vessell'd quicksilver , the quicksilver in the tube will rise to the top of the glass with such a violence as will indanger the knocking out of the head of the glass , and then the ayr will pass by a speedy ebullition through the quicksilver , and it will totally descend into the vessel . i once brake a glass-tube of near forty inches long , by plucking it suddenly out of the vessel'd mercury . . that you cannot so cautiously perform this experiment in any glass tube whatsoever , but some little air will be seen in the top of the tube , when reversed , and before the removal of your thumb , like the little cap of air in the obtuse end of an egge ; so that if you incline the tube to what angle soever ( as in the eighth observable aforesaid ) the re-ascending quicksilver will never totally and exactly fill the tube , but a little cap of air will still stand in the top thereof . . that , use all the artifice and industry you can , you cannot so cautiously fill the tube , but that the cylinder of quicksilver will seem cragged and itched , and never purely smooth and polished , ( though your glass be never so smooth and dry , and your quicksilver never so well purged ) which interstices are filled up with particles of air that lurk 'twixt the contiguities of the glass and quicksilver : and which after the descent of the quicksilver do bubble up , and shoot themselves little by little into that seeming vacuity ( as you may ocularly behold them ) and doubtless are the occasion and hindrance why upon inclination of the tube ( as in . observ . ) the quicksilver cannot totally replenish and fill the tube again . . we filled a tube of . inches with quicksilver , and after inversion of it into a vessel of quicksilver , as in the torricellian-experiment we perceived , just upon retraction of the finger , the little particles of air which remained lurking between the sides of the tube and the quicksilver , on the suddain to become more visible , by a violent and rapid dilatation , flying out like so many little springs wound up , and then all at once set at liberty . . if you immerge the tube into vessels of quicksilver of several capacities and larger surfaces , the descent of it will not alter . . observe that the height of the mercurial cylinder , which here with us is found to be . inches at the least ( if you order the tube handsomely in filling of it ) may seem greatly different from the french observations , and those of forrain experimenters , as parricellius himself , doctor pascal , roberual , doctor pettit , and pecquet , who all assign its altitude to be but about . inches . to this i shall onely at present answer , that this difference of the mercurial cylinder , may partly arise from the variations of the climates , the air being more thin and hot then ours , partly from the difference and altitude of the atmosphere here and there , ( as shall hereafter be made more intelligible ) and partly from the diversity of our measures and theirs , or from the club and combination of all these causes joyned together . to which i may well super-add , the negligence or inconsideration of those that try this experiment ; for you may alter the height of the mercurial cylinder , as you do rudely or cautiously tunnel in the quicksilver into the tube ; for i have some time with exact caution , made it to rise to . inches in altitude from the surface of the restagnant quicksilver in the vessel . i set down . inches as its determinate height , to which it will for the most mount , though you use but a careless kind of carefulness in the management of the experiment . chap. ii. that in the superiour part of the tube there is no absolute vacuity . before we proceed to any further experiments , we will first canvass the cause of this primitive one of torricellius , which has given occasion of trying all the rest ; and then we wil● deliver our hypothesis , which i hope will salve all the strange appearances , not onely in this , but in those stranger that follow . valerianus magnus , and some others are so fond to believe this deserted cylinder to be an absolute vacuity , which is not only non-philosophical , but very ridiculous . . for , the space deserted hath both longitude , latitude , and profundity , therefore a body ; for the very nature of a body consists onely in extension , which is the essential and unseparable property of all bodies whatsoever . . again we have the sensible eviction of our own eyes to confute this suppositional vacuity ; for we see the whole space to be luminous ( as by obser. ) now light must either be a substance , or else how should it subsist ( if a bare quality ) in a vacuity where there is nothing to support it ? . again , the magnetical efluxions of the earth are diffused through that seeming vacuity , as per experiment . . there is some air also interspersed in that seeming vacuity , which cannot be expelled upon any inclination of the tube whatsoever , as by obser. is manifest . . the most full evidence against this pretended vacuity is from the returgenscency of the empty bladder suspended in this vacuity ; for , how should it be so full blown from nothing ? as is by exp. most incomparably evinced . chap. iii. that it is not the efluviums of mercury that fill up that seeming vacuity . before we come positively to declare , what it is that supplies this seeming vacuity , let us draw some negative conclusions , and see if we can prove that it is not supplied with any spirits mercurial , or exhalations : and this we shall most fully do by an ingenious experiment borrowed from the mechanical wit of doctor pascal , which shall passe for the second in the bedroll of our experiments . doctor pascal's experiment . that the deserted part of the tube , is not filled up with any hydrargyral emanations , may be thus evinced ; because he hath found the same experiment to succeed in water onely , without any quicksilver at all : for he took a tube or lead-pipe of . foot in length , made close at the one end in casting of it ; and having filled it full of water , and reversed it into a paile of water , underneath about a foot deep , he found the water to fall within . foot of that in the vessel ; so that the deserted part of the pipe was . foot ; so tall a cylinder of that liquor , being it seems but aequi-ponderous to a mercurial cylinder of . inches . kircher and birthius , it seems , also have tried the like in a lead-pipe of a . foot long , and an inch diameter ; into which at the top was let in a short neck'd weather-glass , or bolt-head , and fastned so to , that no air could pierce the coement , that luted the glass and lead-pipe together , which lead-pipe at the bottome was also fitted with a turn-cock , which when it was once filled with water would keep it in till they had reversed it into a hogshead of water underneath ; and then , by a turn of the cock letting out the water , it deserted the bolt head , and superiour part of the tube , wherein appeared this seeming vacuity . experiment . but for a further confirmation of this truth , let me subjoyn another experiment , ( which shall here pass for our third ) of the same author 's . take a glass-syringe or squirt ; of what length you please , exactly fitted with a squirt-staff ; stop the mouth of your syringe close with your finger , and so drown it over head and ears with hand , and all , in a large vessel of water ; then draw back the squirt staff , and the syringe will appear a vacuity ( which will pain your finger by an introsuction of it in at the orifice ; ) but if then you erect the syringe perpendicular , and draw it all out of the water ( excepting that end closed by your finger ) and then open the orifice , you shall see the water suddainly arise and fill the deserted cavity of the syringe . both which experiments do sufficiently prove that this seeming vacuity may be exhibited without the help of any quicksilver at all , and therefore this imaginary space in the torricellian-experiment aforesaid , cannot rationally be supposed to be repleated with any mercurial effluviums . chap. iv. experiment . that it is not light onely , which supplies this seeming vacuity . take the barrel of a long gun , about . foot long , and bunging up the touch-hole , fill it easily with mercury , and reversing of it into the vessel'd quicksilver , as before , you may measure it , to observe the determinate height aforesaid , which you may easily perceive ; first , by the flushing out of the quicksilver , upon removal of your finger into the vessel where the restagnant quicksilver receives it : secondly , by the re-ascent of the quicksilver upon tilting or plucking the gun quite out of the restagnant mercury , as also by the forceable introsuction of your finger , if you close the muzzle of the barrel within the vessel'd mercury , and so draw it out and reverse it , as also by the plucks and shogs it will give in that action : thirdly , and most perceptibly , by the repletion of it with water , if you draw the tube gently out of the quicksilver in the vessel into a super-incumbent region of water ( which you first poured into the same vessel : ) for then if you stop the orifice with your finger , whilst it stands immers'd in the region of water , and so draw it out and reverse it , you shall perceive it full of water . the like , no doubt , will succeed in tubes of other mettals . again , if light onely ( onely i say , because we do not deny light to be there ) fill up that empty cylinder , it would be certainly far more luminous ( as containing nothing but the pure solary atoms ) than the external medium and region of the air about it , which is confusedly intermixed both with airy magnetical and coelestial particles , besides the halituous effluviums of all bodies whatsoever . but this contrary to observat . chap. v. that the evacuated cylinder in the tube , is not filled with atmosphaerical air only . by atmosphaerical air , i understand such as we constantly breathe and live in , and is a mixt body of luminous and magnetical effluviums , powdred with the influential atoms of heaven from above , and the halituous effluxions and aporrhoea's of this terraqueous globe below : and that no such air fills the superiour cavity of the tube , take this experiment to evince you . experiment . having filled , closed , and reversed the tube ab as before into the vessel'd quicksilver d , fill up the said vessel with water about . inches deep , then lifting the tube gently , but perpendicularly out of the vessel'd quicksilver into the region of water , you shall see the quicksilver and water rise to the top of the glass , and after a short ( but confused ) intermixion the one with the other , the quicksilver will totally descend into the vessel , and the water arise and fill the whole tube excepting a little cap of air in the top of the tube , formerly hinted at in obser. . now if that air in the tube was homogeneous to this in the atmosphaere , the water would never rise to thrust it out of its proper place , or , if it did , it could not squeese through the body of the tube ; but we plainly see the rising water does fill up the place ( as likewise the quicksilver does in the first experiment , where you tilt and incline it ) till it come to that particle of air , which indeed is of the same nature with ours ( and which we told you formerly lurked 'twixt the concave surface of the tube and the cylinder of quicksilver ) and that neither the rising water nor ascending quicksilver , can or does exterminate . this truth also is manifestly evinced from the twelfth observable annexed to the first hydrargyral experiment , which palpably shows that it is not common air which supplies that seeming vacuity . chap. vi. having drawn the former negative conclusions , and demonstrated , that it is not light onely , not mercurial spirits , not atmosphaerical ayr , which is diffused through that seeming vacuity , it will be expected we should deliver something positively , and demonstrate what it is . pecquet ( who i think follows roberuallius therein ) ingeniously conceives , that the whole mass of ayr hath a spontaneous eleter , or natural aptitude in it self to dilate and expand it self upon the removal of all circumambient obstacles ( which he calls the elastical motion of that element ) so that the particle of ayr may be understood to be as many little springs , which if at liberty , and not bound and squeesed up , will powerfully , strongly , and spontaneously dilate and stretch out themselves , not onely to fill up a large room , but to remove great bodies : so that he compares this vast element of air , circumfused about this terraqueous globe , to a great heap of wooll-fleeces or sponges , piled one upon another , the superiour particles of the ayr pressing the inferiour , and hindring their continual tendency to a self-dilatation ; so that all the particles of this atmosphaere ( especially the inferiour sort ) strive at all times to expand and dilate themselves : and when the circumresistency of other contiguous bodies to them is removed , then they flye out into their desired expansion ( or at least will dilate so far as neighbouring obstacles will permit : ) just like the spring of a watch ( which if the string be broke , presently flyes out into its fullest expansion : ) which elastick motion in the ayr then ceases , when it comes to an aequilibration with those circumjacent bodies that resisted it . that this is not onely an ingenious hypothesis , but that there is much of reality and truth in it , i think our following experiment will to safety of satisfaction demonstrate . onely we differ from pecquet in the strict notion he hath of rarefaction and condensation , which he supposeth to be performed without either intromission or exclusion of any other extraneous body whatsoever . now how ayr or any other body should diminish or augment its quantity ( which is the most close and essential attribute to bodies ) without change of its own substance , or at least without a reception or exclusion of some other extrinsecal body , either into , or out of the porosities thereof , sounds not onely harsh to our ears , but is besides an unintelligible difficulty . now though we cannot by sensible and mechanical demonstration shew how any new substance or subtler matter ( than ayr is ) which enters into the tube to replenish that seeming vacuity , and to fill up the aerial interstices ( which must needs be considerable in so great a self-dilation ) yet we must ( considering the nature of rarefaction aforesaid ) be forced to believe it : and perhaps some happy experimenter hereafter may come to give us a better then this speculative and metaphysical evidence of it . that the hollow cylinder in the tube is not onely fill'd up with the dilated particles of ayr , but also with a thin aetherial substance intermingled with them : . let us suppose therefore ( at random if you please ) that there is a thin subtle aetherial substance diffused throughout the universe ; nay , which indeed , by farr the greatest thereof : in which all these luminous and opace bodies ( i mean the starrs and planets ) with their luminous and vaporous sphaeres ( continually effluviating from them ) do swim at free and full liberty . . let us consider that this aether is of that subtil and penetrative nature , that like the magnetical effluviums , it shoots it self through all bodies whatsoever , whos 's small pores and interstices are supplyed and fill'd up with this aetherial substance , as a sponge with water . . let us add to the former considerations , that the ayr hath not onely a strong elatery of its own ( by which it presses continually upon the earth , and all bodies circuminclosed by it ) but it also ponderates , and is heavy , in its own atmosphaere . but because i am resolved you shall take nothing upon the trust and reputation of the best authour , take this experiment to prove the ayr 's gravitation ( in proprio loco ) as the vulgar philosophy cals it . experiment . take a wind-gun ( which new artifice is now common ) and weigh it exactly when empty , then by plying the pump-staff charge it soundly and weigh it again , and you shall find it much heavier then before ; yea , a large bladder , full blown , will weigh more then its self emptied , and manifest this inequality upon a ticklish pair of scales . now though this experiment seems onely to evince the gravitation of ayr condens'd , yet it consequentially follows , that ayr also in the liberty of its own sphaere , is proportionally ponderous ( though it is a difficult point mechanically to evince it , unless we were actually above the atmosphaere , or in a vacuity to weigh it there in a thinner medium then here we are able to do ; ) yet , if i mistake not , i have an experiment in banco which will give some mechanical evidence of this great mystery , which here , with all its consequences , i shall deliver . experiment . the . of may , . i took two tubes , one of . inches , the other ½ in length , and of different diameters ; and filling them both at the bottom of hallifax-hill , the quicksilver in both came down to its wonted pitch of . inches , thence going immediately to the top of the said hill , and repeating the experiment again , we found it there to fall more then half an inch lower then it did at the bottom or foot of the said hill. pecquet relates , that dr. pascal himself tryed this experiment upon a mountain of perches high , near claramont , and he found quicksilver there at the hill to descend lower by three inches , and somewhat more , then it did at the bottom ; so that , according to the analogy & proportion of both , and some other considerable circumstances , we might not only mechanically find out the perpendicular height of our great hill here at hallifax , or any other mountain whatsoever , but venture notably at the height of the atmosphaere it self . for , to manage the principles we have formerly laid down , first , the reason why the quicksilver descends at all in the first experiment , is from its exceeding gravity . secondly , why it falls no lower then . because a cylinder of that weight does just aequipoise the elastick power of the ayr without , and therefore after a few vibrations up and down ( as is observable in all statick experiments ) they arrive at a counterpoise . but the reason now ( as to our particular mountain's experiment ) why the counterpoise should alter at the top from that at the bottom of the hill , and the descent of the quicksilver be so unequal , is not so much from any alteration in the elastick power and virtue of that ayr at the top , from that at the bottom of the hill ; as from the variation of the gravity of the superincumbent ayr : for , a longer , and so consequently , more weighty columne of ayr , presses upon the vessel'd quicksilver at the bottom of the mountain , and so makes the quicksilver in the tube , rise higher than at the top of the mountain ; which being so much nearer the top of the atmosphaere , a lesser weight of superponderant ayr makes a lesser quantity of quicksilver arise in the tube : and so come the mercurial cylinders to vary in their altitudes , viz. from the natural supergravitation of more or less of the superincumbent atmosphaere . so that it is more than probable , that the higher one rises in the ayr , to try this experiment , the quicksilver in the tube would fall down lower ; and if the experiment could be try'd at the top of the atmosphaere , no quicksilver at all would remain in the tube , but fall down to a level with that in the vessel . i could wish that some of our canary-merchants would get this experiment try'd at the top of the pike of teneriffe , which is deservedly famed for the highest hill in the world . object . . but i see you are ready to reply , and say , that the inequality of the mercurial cylinder ( in the mountain-experiment aforesaid ) may every whit as rationally be supposed to proceed from a change in the elastick property of the ayr , which may be more vigorous at the bottom , and more faint and feeble at the top of the hill , and so force a greater or lesser quantity of quicksilver up into the tube . object . . i know how harsh it sounds , that ayr should gravitate in its own sphaere , and we , and all other terrestrial inhabitants , be insensible of it ; and that which augments the improbability , is , that water we experimentally know ( which is a fluid and dissipable body , as ayr is ) does not gravitate in its own proper place ; for if we dive never so deep , it 's so far from depressing of them lower , or weighing on them , that it is readier to buoy them up again : and why should not we conclude the like of its next neighbouring element , the ayr ? to the first objection , i answer , that though i should grant that there should be some difference in the elatery of some of the aerial particles from others , yet to be so great in so small a distance as four or five furlongs , 't is not so easily credible . i shall answer your second objection with this following ( which may pass for the . ) experiment . fill the tube , as in the first experiment , and drown both it and the vessel of restagnant quicksilver ( by letting down all carefully with strings into a hogshead , or great cistern of water ) and you shall see that the deeper you immerge the tube , the higher still will the quicksilver in the tube arise . let the vessel of water be of a greater or lesser plane in the surface , it matters not ; because onely those parts of water that hang perpendicularly over the vessel'd quicksilver do gravitate upon it : we drown'd a tube to . inches in depth , above the superficies of the vessel'd quicksilver , and it raised the quicksilver in the tube about ● / above the stint of . inches , at which it formerly stood ; just according to the fore-observed proportion 'twixt the weight of the water and quicksilver : a cylinder of the former of . foot , being but aequiponderant to a cylinder of the latter of . inches . of which noble experiment , we must confess , the first hint was given us , by those acute and singularly accomplished gentlemen of townley-hall in lancashire , who were as judicious as honourable spectators of these our hydrargyral experiments ; and whose mechanical prognosticks seldom failed , but were still made good by the future event of the experiments . by which it most evincingly appears , that water does gravitate in its own sphaere ( as they phrase it ) which now we may retort upon the second objection , and say , that if water do gravitate , then why not ayr in their proper sphaere ? both being fluid , dissipable , and co-neighbouring elements ; and so consequently whether in ayr or water the experiment be tryed , this effect will follow , that the deeper you immerge the tube in either element , the higher will the mercurial cylinder rise : and contrariwise , as . foot of superjacent water would raise up a mercurial cylinder of . inches ; so the same cylinder of . inches is raised by a column of the height of the whole atmosphaere it self . but we may by a far more facile and cheaper experiment evince the gravitation of water in its sphaere , which is observable in the common experiment of a syphon ; through which , the water , by suction , being first set on motion , it is easily observable , that the flux in the extravasated leg of the syphon , is at first most strong ; and proportionally decreases , as the water in the vessel sinks lower and lower towards the bottom of that leg immerg'd in it : which cannot proceed from any other cause imaginable , but from the supergravitation of the high parts of the water upon the lower , which being thereby more strongly forced up the shorter leg of the syphon , the flux thereby is stronger in the longer ; and so faints , as the bulk of the superponderant continually decreases . chap. vii . the reasons of all those extravagant phaenomena , which we observed in the first experiment of torricellius . . because the smaller weight of quicksilver is not able to master the elastick pressure of the external ayr. . because then the cylinder of quicksilver superponderates and overpowers both the ayr 's elastick virtue and gravity . . because at that stint of . inches , the internal cylinder of quicksilver comes to an aequilibration with the external cylinder of ayr , which presses upon the vessel'd quicksilver . . and . because that in wider and longer tubes there is at first included a greater quantity of quicksilver , it does more strongly overpower the elastick resistence of the ayr , and so will come ( though with more vehemence and swiftness ) to its wonted altitude of . inches . . because by addition or diminution of the vessel'd quicksilver there is a change in the tube and vessel , but not in the mercurial cylinder in the tube ; for that alwayes keeps at an equal altitude from that in the vessel . . because the mercurial cylinder is very heavy , and quicksilver in quicksilver moves as easily as a bucket of water in the whole well . . because thereby there is onely a change in the tube , but not in the altitude of the mercurial cylinder ; for in that angle of inclination , the perpendicular is still . inches . . because the quicksilver , by its long descent , having acquired a greater motion than was requisite to bring it down to its determinate altitude , cannot suddenly stop there , but by several vibrations up and down , gradually comes back to its wonted altitude ; as we see pendents , which multiply their undulations before they rest in their desired perpendicularity . . because the atoms of fire and heat ( which is alone ) penetrating through the tube , do expand and dilate the aetherial ayr in that seeming vacuity , and so consequently depresse the mercurial cylinder ; or else , contrariwise , upon the approach of cold , some aetherial atoms pass out again through the glass , and so the mercurial cylinder mounts higher . . because it is a medium somewhat thinner than ayr alone is ; the reason of your finger's exuction may be the elastick pressure of the external ayr , without striving either to come in it self , or thrust any other body into the tube ; as also the tendency of the aetherial atoms within , to be a free and proportional commixtion with aerial particles without . . because when the continuity of the external and internal quicksilver is broke , the mercurial cylinder is by the elastick pressure of the ayr ( which then prevails ) forced up into the top of the tube ; which done , then the quicksilver , by its gravity overpowring , the atmosphaerical , or unexpanded ayr , falls down , and gives place to the lighter body . . because no contiguity , it seems , in dry bodies ( how close soever ) can exclude the interveniency of ayr. having in our last ( . experiment ) proved sufficiently the ponderosity of water , and its gravitation upon the external quicksilver in the vessel , we will now come to shew you likewise its gravitation upon the internal quicksilver in the tube . experiment . we took such a like ab ( as in the . eperiment ) near four foot in length , and fill'd it full of quicksilver , except a segment ( a of about . inches , which we filled up with water ; ) then reversing the tube , and holding it so long in that posture , till the quicksilver and water had exchanged their places , we then drown'd it in the vessel●d quicksilver d , and there withdrawing our finger ( as in the . experiment ) the quicksilver in the tube descended an inch , and more , lower than the ordinary stint , ( viz. within ½ inches of that in the vessel : ) and this we try'd in glass-tubes of . and . inches in longitude : so that the tube will be replenished with three cylinders ( viz. ) of quicksilver , water , and ayr. in which experiment there are three or four remarkable appearances , which ought not to pass our observation : . that after inversion of the tube into the vessel'd quicksilver , before you draw away your finger from the orifice , you may observe continual bubbles of ayr to pass through the water by an ebullition , and so presently to create the little cap of ayr , formerly observed ( in our . observ. ) though in the interim the orifice a , be never so closely stopped . . that after the removal of your finger , and collapsion of the mercury to , as aforesaid , the volatile bubbles of ayr still pass through the region of water for a long time . . that if the cylinder of quicksilver , included in the tube , be not above . inches , besides that of the water , no effect at all will follow . . that if the cylinder of quicksilver , included into the tube , be but one inch higher than its ordinary pitch , then , upon making the experiment , it will fall proportionally lower , according to the weight of the supergravitating water . this experiment , with those considerable circumstances annexed to it , makes the water's gravitation more eminently appear : for , since . inches of water is almost aequiponderant to one inch of quicksilver ( as is evident by the statick tables of getaldi ) and the quicksilver in the tube being depressed by the superincumbent cylinder of water of . inches , it follows , that it would necessarily depress it one inch lower than the ordinary stint . but unless the cylinder of quicksilver be so great , ( or at least that of quicksilver and water to be so powerful ) as that it be able to overcome the elastick pressure of the atmosphaere , no effect at all will follow , because there can be no descent of either : and as for those aerial atoms which pass by bubbles through the body of the water , they are those formerly observ'd for to lurk 'twixt the contiguity of the quicksilver and tube ; nay , and perchance , and in the body of the quicksilver and water too , because they cease not after the collapsion and descent of the mercury . thus having mechanically evinced the gravitation of those two fluid elements , both water and ayr , in their proper places and regions ; we may come to make good the second part of our hypothesis , which is the air 's elastick virtue and property . for the demonstrating of which , take this following experiment . experiment . fill the tube ( as in the former experiment ) and let the segment a of . inches , which was formerly fill'd with water , be onely fill'd with ayr ; then , after you have revers'd it into the vessel'd quicksilver d , and withdrawing your finger , you shall see the quicksilver in the vessel so to fall , that it came down . inches lower then its wonted and determinate altitude : we fill'd the same tube , of . inches long , within two inches of the top , and then reversing it , as before , it descended two inches below the ordinary stint . we also tunnell'd into the tube a cylinder of quicksilver , but of five inches in altitude ( letting the ayr supply the other segment of . inches ; ) and reversing it , as before , it fell down within two inches of the quicksilver in the vessel . observe , that in these mixed experiments of ayr and quicksilver , or water and mercury , or all three together , that when you have revers'd the tube , you must hold it close stop'd so long perpendicular , till the several bodies have acquired their several respective and proper places . to this experiment likewise we must annex one considerable phaenomenon : first , that before you withdraw your finger , you shall perceive the internal quicksilver in the tube , to press so sensibly upon your finger , as if it would force an entrance out , both before and after it was immerg'd in the vessel'd quicksilver : which protrusion cannot possibly be supposed to proceed from any other cause , but the elatery of the included ayr ( for the pressure was far greater than the natural gravity of the whole tube of quicksilver could make ) which ( upon the removal of your finger ) having got some liberty to manifest it self , it depells the quicksilver so far below its determinate height : hence it appears , that ayr , besides its gravity , has a nobler rarefactive faculty , by which it forces the quicksilver to so considerable a descent , whereas water , by its weight onely ( as is manifest in the precedent experiment ) and no innate elatery , did depel the succumbent quicksilver in the tube . but because the ayr 's elatery is one of the chief parts of our hypothesis , we will not onely make it good by one , but confirm it by many more succeeding experiments . experiment . fill any manner of tube , not above . inches in length , half with quicksilver , and half with ayr , and then closing your orifice with your finger , and reversing it into vessel'd quicksilver , as in the former experiments , you shall ( upon removal of your finger ) see the quicksilver fall an inch lower then before , as being depell'd by the dilated ayr ; if then you pour water upon the restagnant quicksilver in the vessel , to about one inch deep , and draw the tube out of the quicksilver into the region of water above , you shall see the quicksilver hastily to arise some inches in the tube , and then the water and it confusedly to intermingle one with the other . lastly , ( the quicksilver being wholly descended into the vessel ) the water will arise to fill the one half of the tube . this we tried in glasses of , , and inches in length . in the first it fell . inch , in the second it fell ½ inches , in the third inches , and more , from the first point it stood at , before you immers'd it in the vessel'd mercury . this experiment drew me on to the trial of another : for i thought if quicksilver would descend with a quantity of ayr included with it in tubes below the required pitch and standard of . inches , then probably some such like effect would follow in water and ayr ( included in any of the longer sort of tubes ) though much lower then . foot , which is found to be the standard of water in its ascent in pumps and other instruments ( as is besides delivered in exper. ) experiment . we therefore fill'd our glass-tubes of inches , half with water , and the rest with ayr , and afterwards invers'd it into a pail of water , one or two inches deep ; the success was , that withdrawing your finger , as before , the internal water in the tube , did shoot about two inches lower then before , and with such like vibrations ( though far shorter than those in quicksilver ) lastly , if you immers'd the tube one foot deep in the pail of water , the water in the tube would rise somewhat higher than before . note , that in these two last experiments , the descent or fall of the quicksilver or water , was most notable about the midst of the tube , viz. when it was equally fill'd with ayr and quicksilver , or ayr and water . which experiments do not onely make good what is formerly delivered of the ayr 's elastick pressure , but also it renders doctor pascal's experiment , of the descent of water to ● . foot , very creditable to those that want instruments to try it . experiment . we also tried that experiment of roberuallius , quoted by pecquet , pag. . i took one of those little bladders that are in fishes , ( that in the little fish , call'd with us , a graining , is best ) and after it had been a few dayes dried , i let out all the ayr of it , and tyed the mouth of it again so close , that no new ayr could re-enter ; then i gently wet it on the out side , and dropped it down to the bottom of the tube , that it might the better stick there , and not be buoyed up with the quicksilver poured in upon it ; then cautiously tunnelling in the quicksilver , and reversing the tube , as in the first experiment , we found that after the quicksilver was come down to its wonted pitch , the fish-bladder was full blown , and did swim on the top of the quicksilver ; which , upon the admission of the external ayr , grew instantly flavid and empty again . now , what else is the reason of the bladder's intumescences upon collapsion of the quicksilver to its wonted standard , but the spontaneous dilatation and elastick rarefaction of that little remnant of ayr , skulking in the rugosities thereof ; and then ( upon removal of the circumpressing quicksilver ) expanding it self in the bladder , as well as that does in the tube ? the reason of its flaccescency , upon admission of external ayr , is , because then the elater of the external ayr is so strong , that it forces the embladder'd ayr into its former extension and consistency again . but hold ; before i pass from this experiment , i must take pecquet in hand , who , upon confidence of this experiment , insults highly over those that admit not of his rarefaction , but will introduce a new aetherial substance to intermingle with the dilated ayr to fill up this seeming vacuity . object . . if any aetherial substance penetrate the glass-tube , it rushes in equally on all sides towards the bladder , pendent in the centre ; and so , in all probability , would rather press and squeese the vesicle on all sides closer together , than ( by an opposite motion , and re-action upon it self ) extend and dilate it . object . . again , since it enters in so freely at the pores of the bladder , what should improfen it there ? since the pores , which gave it admittance , are continually open , and manifest themselves so to be , when any external ayr is admitted into the tube , for then it seems the aether flyes out indeed , and the ayr is recondensed again into its natural and ordinary consistence . object . . again , if the quicksilver descending do impel the aether through the pores of the glass , to help the dilated ayr , in suppliance of that seeming vacuity ; why should not quicksilver totally descend , and fill the whole tube with aether , and so , consequently , quicksilver should descend in any tube ( though lower than the ordinary stint of . inches ) whatsoever contrary to experiment . object . . but if there be a superaerial region of aether , as much lighter and subtiller than ayr , as ayr is then water , how comes any part of it to be diffused , or dispersed throughout our elements ? or , if it be , why should not the aetherial particles fly all away to their proper sphaere ( or be rather forced thither by the continual pressure of these heavier bodies ? ) as we see no ayr will abide in water , but is forc'd up into its proper region and element above it . solut. . we grant , that the aether pierces equally in on all sides of the tube , and so likewise on all sides of the bladder ( into which it would not have entred ) had there been no ayr at all which had freely open'd in its dilation to receive the coming aether into its intimate recesses . solut. . why the aether hits not out again ( during the interim of the ayr 's expansion ) may be , because it has either changed its figure , or it and the aërial particles may be in a new motion , which may not cease till overpowred by the re-admission of new ayr. but what 's the reason in a bladder half-blown , and held to the fire , or laid in warm ashes , the internal ayr should rise and swell up the bladder , as in this experiment ? if you say , from the atoms of fire , or heat , which penetrate into the bladder ; the same objection i then make to you , ( as he there to me ) why could they not hit out , as well as in , through the same pores ? the like may be said of the ayr in a weather-glass , upon application of any thing that is hot to the head of the tube . solut. . now , why the quicksilver does not totally descend , we have told you , is from the resistence of the atmosphaerical ayr , which forces up a cylinder of quicksilver of that height of . inches ; but as we have since declared , if the experiment could be made at the top of the atmosphaere ( which is not very high ) then it would totally descend , and the aether there would fill the whole tube . solut. . it is every whit as probable , that aetherial atoms may be interspersedly diffused through all our elements , as that ayr may be , or the magnetical effluviums : the same we have made probable ( by its being in water and quicksilver ) and the latter , no man ( that knows any thing of magnetical operations ) doubts of . before we take our leave of these subtil and rare experiments , i will give you that ingenious , but very difficult experiment of auzotius , as quoted by pecquet , which shall bring up the rere in this muster-role of our experiments , and which will confirm all we have formerly delivered . experiment . of auzotius . take a long tube , with a head like a weather-glass , onely open at both ends , as a b , and with a circular ledge at b ( to tye a bladder about ) as also a little pipe g , which opens into the head thereof , reverse it , and into the mouth of the head let down a hollow cube of wood or ivory c , as large as the head will contain ; which with its four corners may rest upon the neck of the glass ( as in the second figure : ) then take a small cylinder of glass , of above . inches , and set it in the middle of the cube c , and close the mouth of the head b , and the pipe g with bladders , so that no ayr can get in ; then stopping the orifice of the long tube a , with your thumb , let another tunnel-in mercury at the top of the small glass-tube f , which will first fill the cube c , and then running over , and falling down the interstices , that the four angles of the cube c makes with the neck of the glass , shall at last come to fill both tubes : lastly , closing the orifice of the great tube a into the vessel'd quicksilver , and there withdrawing your finger , as in the former experiments , you shall see all the quicksilver in the small tube f b , to fall into the cubical vessel c , ( which being not able to contain it ) it , together with all the quicksilver , in the head and neck of the great glass-tube , will come down to its wonted pitch e . inches of that in the vessel . which shews , the descending quicksilver perpetually observes its sandard-altitude from what height soever . but the great business is , if you open the little pipe g , and let in any ayr , you shall not onely see it to depel the mercurial cylinder a e , but to force up the quicksilver out of the cube c , into the small tube b f , to its wonted altitude of . inches , and totally to expel the mercurial cylinder e a out of the tube : which ocularly demonstrates , that it is the atmosphaerical ayr that ( in the first experiment ) raises and keeps up that cylinder of quicksilver in the tube of . inches in altitude , or thereabouts . chap. viii . additional experiments made at townley-hall , in the years . and . by the advice and assistance of that heroick and worthy gentleman , richard tovvnley , esq r. and those ingenious gentlemen m r. john , and m r. charles tovvnley , and m r. george kemp . the last year , . came out that excellent tractate of experiments of esq r. boyle's , with his pneumatical engin , or ayr-pump , invented , and published by him ; wherein he has , by virtue of that rare contrivance , outdone all that ever possibly could be performed by our late mercurial and experimental philosophers : and , indeed , to give a true and deserved character of that worthy production of his , i must needs say , i never read any tractate in all my life , wherein all things are so curiously and critically handled , the experiments so judiciously and accurately tried , and so candidly and intelligibly delivered . i no sooner read it , but it rubbed up all my old dormant notions , and gave me a fresh view of all my former , and almost-forgotten , mercurial experiments . nay , it had not that effect onely on me , but likewise it excited and stirr'd up the noble soul of my ever honoured friend , mr. townley , together with me , to attempt these following experiments . experiment . we took a long glass-tube , open at both ends , and put the one end into quicksilver about one inch deep ; then at the upper end we poured in water by a tunnel : the effect was this , ( as was presurmised ) that the water rise up to a cylinder of . inches above the surface of the quicksilver in the vessel , but then it would rise no higher , but brake through the restagnant quicksilver in the vessel , and swum upon the top thereof , which is consonant to the series and chain of our former experiments : wherein it is proved , that one inch of quicksilver is aequiponderant to above one foot of water ; and therefore there was reason that one inch of restagnant quicksilver should support a cylinder of . inches of water , but no more . but as touching this proportion of water and quicksilver , because we have formerly only given it to you upon trust from maximius gletaldi , we will now give you an experimental eviction of it . experiment . we fill'd a glass-vial ( being first counterpoised with mercury ) and then weighed it ; afterwards we weighed as much water in a glass-vial , of a known weight , as counterpoised the quicksilver , and then measuring the water in the mercurial vial aforesaid , we found it to contain near . times as much water as it did of mercury . experiment . we fill'd a tube with quicksilver , as in the torricellian-experiment , wherein much leisure and accurateness were used in filling the tube , to make a polite equal mercurial cylinder , and after immersion thereof into the vessel'd quicksilver , we put both the tube and vessel into a frame made for that purpose , and let it stand perpendicular therein for certain dayes together ( viz. ) from the . march , to the . april after , to observe if it would vary and alter its standard , which we found it do considerably ; for sometimes it was half an inch higher or lower then the mark and standard we left it first at . i think , according to the variation of the atmosphaere in its temperature : and if you observe strictly , you shall see that the quicksilver in the tube does never precisely observe the same standard not a day together , nay sometimes not an hour . experiment . again , we tried the torricellian-experiment aforesaid , in a glas-ssyphon of ½ inches in length , and after immersion of both ends into two several vessels of quicksilver , the internal quicksilver fell down to its wonted standard of . inches in both shanks of the syphon : having applied warm clothes to the top of the syphon , the quicksilver descended in either leg the breadth of two barley corns lower than the ordinary stint . we gently lifted one of the legs out of the vessel'd quicksilver , and then the quicksilver in that leg rose violently up , so that part of it passed over into the other shank : then having speedily again drown'd the aforesaid leg into the vessel , we observ'd the quicksilver in both legs to have fallen much ( upon the admission of that ayr ) and to stand in both legs at an equal pitch and height , as it did again the second time , upon admission of a little more ayr , though the quicksilver then did not rise high enough to pass over into the other shank as before . experiment . we took the same syphon again ( as before ) and then only fill'd one of the legs with quicksilver , leaving the other full of ayr ; then stopping both orifices , reversed both shanks into two several vessels of quicksilver , as before ; then opening both orifices , the effect was , that the quicksilver fell in one tube , and new quicksilver rose out of the other vessel into the other tube to an equal altitude . experiment . we fill'd a tube ( though with much difficulty ) such an one as is here described , with quicksilver , then invers'd it into quicksilver , as before : the first effect was , it fell leisurably down out of the head h , and stood at d , . inches in perpendicular from the quicksilver in the vessel e. the second effect was ; ayr being let in 'twixt c and b , the quicksilver rose from d , its former standard , to a : so that from a to b , and c to e ( for so far as c it fell upon admission of ayr ) made up its wonted standard again . experiment . we took a glass-cruet , with a small spout , and fill'd it with water , and afterwards luted the great mouth a , so that no ayr could get in ; then turn'd the small spout downwards , but no water came out of the cruet into the open ayr , inversing likewise the small snout into oyl , no water descended , nor oyl , though a lighter liquor , ascended ; then filling the former cruet with milk , though upon inversion of the cruet none of it would fall out into the ayr , yet being inversed into water , these two liquors changed places , the milk descending in a little still stream , the water ascending in the same manner in two constant little streams , running counter one to another ; in the neck of the cruet we tinged the water with indico , the better to distinguish their streams . experiment . we fill'd the former cruet with quicksilver , and immers'd the snout into the water ( having first well luted the mouth of the vial ) but no exchange of place followed , unless by much shaking of the quicksilver , you forced it little by little out ; and so either water or ayr passed up instead thereof . chap. ix . experiment . april . ( . ) we tryed the torricellian-experiment in the porch at the new church in pendle , ( which standeth upon a considerable height ) the weather being clear , fair , and moderate , about ten of the clock in the morning , the tube about . inches in length , which we fill'd with very much care and diligence , to make a polite mercurial cylinder , and there we then found the mercurial standard to be / inches . we tried the same experiment with the like accurateness , and in the same tube , at the beakon upon the very top of pendle-hill , on the same day betwixt twelve and one a clock , ( the ayr being there much colder then at bottom , or at new church aforesaid ) though the sky was as clear ; and there the mercurial cylinder was lower then before at new-church , by a just inch , being fallen precisely to / inches . about three a clock of the same day , the said trial was made ( with all the former circumstances ) at barlow , the lowest place ( for conveniency ) near the said hill , much lower then the place of the first trial , the ayr being very much hotter then at the time of the first trial ; and there the cylinder of quicksilver was equal to that in the first trial ( viz ) / inches . by which it appears , that ( if the ayr at barlow had remain'd of an equal temperature with that of new-church ) the quicksilver , in all probability , would have fallen lower then the inch we observed . experiment . at the top of the said hill , we put into the same tube ( which was divided into . equal divisions of spaces ) as much quicksilver , as being stop'd and inversed , the ayr remaining in the top of the tube , fill'd / , or thereabout , of the forementioned divisions , and the quicksilver , the remaining part of the tube . the tube being thus immers'd , and the finger withdrawn , the internal ayr dilated so as to fill of the above-mentioned parts / . and there remain'd in the tube a cylinder of quicksilver containing in length / inches . we tried the same experiment at the bottom of the said hill , the tubes being fill'd , as above , and the ayr / . dilated to / . and the cylinder was in height / . inches . experiment ii. we took another tube , containing in length from the superficies of the external quicksilver into which we immers'd it ( for so we measure all our lengths ) about . inches , containing equal divisions of space , . and about an half , represented here by ab , which we fill'd so with quicksilver , that being revers'd and stop'd at b , there remain'd . divisions fill'd with ayr from a to e : then the quicksilver being left at liberty to fall down into a dish underneath , it fell near to the mark to l. so that the ayr dilated , fill'd the space a l , containing of these divisions / , and then the cylinder l b was in perpendicular height / . inches . we brought this tube , with the same mountain-ayr in it , by the help of a long tube of wood , having a dish fastned to the open end of it , and both full of quicksilver , into which we put our tube , ab , ( which instrument you have here represented ) and at the bottom of the hill the quicksilver rose up unto the mark m , under the . division . so that the ayr dilated , fill'd of the equal parts / , and the quicksilver in b was in height / . inches . then we put out this mountain-ayr , and let into the tube the same quantity of valley-ayr , which fill'd the part a e , containing also . of the equal divisions aforesaid ; and then the end of the tube b opened the ayr dilated to the mark n. so that it contain'd / . parts , and the quicksilver in perpendicular height , / . that you may at one glance behold all the varieties of these dilatations of ayr , and height of the mercurial standard , i have supposed the line ab to represent all the tubes . ae still represents the ayr left in them , ad the ayr dilated , bd the quicksilver . in the long tube . at the top of the hill. at the bottom of it at barlow . ae — / — / equal parts of spaces , inches . ad — / — / bd — / — / in the lesser tube . at the top of the hill. at barlow with ayr. at barlow with valley-ayr . ae — — — ad — / — / — / bd — / — / — / now before we pass to any further experiment , we think it fit to make and denominate several considerable spaces of the tube in the mercurial experiments , which will avoid both confusion and multiplicity of terms for the future . let ab be the tube in which quicksilver ( in case it were totally void of ayr ) would stand in a perpendicular cylinder above the quicksilver in the vessel from b to c. so we shall call that line or space , bc the mercurial standard . but if in the tube there be left as much external ayr as would fill the tube from a to e , and that then the quicksilver would fall from c to d , and the ayr be dilated to fill the space ad , then we shall call bd — the mercury . cd — the mercurial complement . ae — the ayr. ed — the ayr 's dilatation . ad — the ayr dilated . where note , that the measure of the mercurial standard , and mercurial complement , are measured onely by their perpendicular heights , over the surface of the restagnant quicksilver in the vessel : but ayr , the ayr 's dilatation , and ayr dilated , by the spaces they fill . so that here is now four proportionals , and by any three given , you may strike out the fourth , by conversion , transposition , and division of them . so that by these analogies you may prognosticate the effects , which follow in all mercurial experiments , and predemonstrate them , by calculation , before the senses give an experimental thereof . experiment . we tried the pascalian-experiment in a tin-tube of . foot long , made of several sheets of tin , and closely soddered up with peuter : to the upper end whereof we fastned a long glass-tube , open at both ends ; then , having soddered up the lower end , we reared the tube to a turret at townley-hall , and fill'd it with water ; then closing the top of the glass-pipe , and immersing the other end of the tin-tube into a cistern of water a foot deep , we opened the lower end , and perceived the water to fall out of the glass-tube into the tin , but how far we could not tell , onely we conjectured to be about the proportion given by doctor pascal ; viz that a cylinder of water stood in a tube about foot high : but presently our glass-tube , at the juncture to the tin , began to leak , and let in ayr ; so we could make no further process in the experiment : onely one thing we observed in filling of the tube , that after the water which we tunnelled in had gone down a pretty way into the tube , part of it ( by the rebounding ayr ) was violently forced up again , and shot out at the upper end of our glass-tube two or three foot high into the open ayr : which experiment may be a caution to pump-makers , & all artificers that deal in water-works , that they attempt not to draw water higher then foot ( its standard-altitude ) left they lose both their credit , cost , and pains in so unsuccessful a design . for i remember in my lady bowles her new water-work at heath-hall , near wakefield , where the water is raised at least . yards high , the simple workman undertook first to do it by a single pump ; but seeing his endevours were frustrated , he was forced to cut his cylinder in two pumps , and to raise it , first , eight yards into a leadcistern , and then by another pump to raise it out of that other , eight yards , into a cistern above . chap. x. now to salve all these mercurial phaenomena , as also those mixed experiments of quicksilver and water , quicksilver and ayr , ayr and water , in single and double tubes and syphons of all bores , divers learned and ingenious heads have excogitated several neat , though different , hypotheses : for , to omit the whimsies of two grandees , that is , valerianus and hobbs , which so grosly philosophize : the former affirming the deserted space in the tube to be an absolute vacuity ; the latter , to be replenished with this very common ayr which we breathe in ; which creeping up 'twixt the contiguity of the glass and quicksilver , fills up that conceited vacuity . to omit these exorbitant conceits , i find two or three more intelligible and rational hypotheses . the first is of roberual and pecquet , of the ayr 's elasticity and gravitation , which we have formerly embrac'd , onely with this addition , that whereas they will have rarefaction and condensation to be performed without any increase or loss of quantity ( which can never be conceived ) we admit of an aetherial substance or matter intromitted and excluded , the bodies so chang'd as we formerly explicated . the second hypothesis is of the vacuist's ; such , i mean , as , though they hold this spring of ayr , yet in its dilation will admit of no aether or forrain substance to enter the pores thereof ; but the particles , so dilated , to remain so with interspersed vacuities : and this opinion hath many eminent advocates and avouchers , gassend , doctor ward , doctor charleton , &c. the latest novellist that hath undertaken this experimental philosophy , is one linus , aliâs hall , who hath excogitated a new principle of his own , whereby he not onely salves all the phaenomena in the torricellian-experiments formerly delivered ; but also all those stranger experiments discovered since by gerricus and boyl's pneumatical engines . ( his principles he thus layes down . ) . that there is an inseparability of bodies , so that there can be no vacuities in rerum natura . . that the deserted space of the tube ( in the torricellian-experiment ) is fill'd with a small film of quicksilver , which being taken off the upper part of it , is both extenuated and extended through that seeming vacuity . . that by this extended film , or rope ( as he calls it ) of dilated quicksilver , the rest of the quicksilver in the tube is suspended , and kept up from falling into the vessel . . that this funicle , or rope , is exceedingly rarefied and extended by the weight of the pendent quicksilver , and will ( upon removal of that violent cause which so holds it ) re-contract it self into its former dimensions again , and so draw up what body soever it hath hold of along with it ; as the effluviums of an electrick upon its retreat , plucks up straws , or any other thing with it that it is able to wield . . that rarefaction or condensation is perform'd without any increase or losse of quantity in the body so chang'd . . that this extension of the film of quicksilver , is not indefinite , but hath a certain limit , beyond which it will not be stretch'd ; and therefore if the tube be of an exceeding great height , the quicksilver will rather part with another film , and extend that , and so a third , or fourth , till it come to the standard of . inches , where it rests ; having not weight , nor power enough to separate another film from it self . upon reliance on , and encouragement from these principles , he undertakes all difficulties , and engages with three great experimental-philosophers , torricellius , schotus , and boyle , and resolves all the phaenomena of their engines . . as first , why the quicksilver in the tube , under . inches , descends not at all ? because it sticks with its uppermost surface so close to the top of the tube , that there is not weight enough to break that adhaesion : the reason whereof is , because there is nothing to succeed in the room of the descending quicksilver , and therefore it firmly sticks there , ne daretur vacuum . . in longer tubes it falls to that standard , because then the greater weight of the quicksilver is able to break that linck of contiguity or adhaesion ; and therefore the uppermost surface of the quicksilver being sliced off , is dilated into a tenuous column , or funicle , which supplies that seeming vacuity . . the reason why the internal quicksilver in the tube does ascend , upon plucking the tube out of the restagnant quicksilver , is , because then ( some of the quicksilver in the tube falling out ) the contiguity is not onely broke , but the quicksilver in the tube being made thereby lighter , the rope is able to pluck it up ; which it doth by retracting and shrivelling it self up to the smalness of its former dimension ; and thus by no violent distention , but spontaneous , you must perceive all the experiments of the weather glass to be performed by a tenuous funicle of ayr , and , in the pascalian-experiment , by a rope of water ; and so of other liquors , where this seeming vacuity is created . by this tast of philosophy you may easily imagine how he salves all the mercurial phaenomena , and those of the pneumatical engine . the arguments by which he strives to authenticate and make good his hypothesis , are these four negative ones ; by which he strives to impugn the doctrine of those that hold the ayr 's gravitation and elasticity . the first ( which is the main and herculean-argument ) is from the introsuction of the finger , so observable in the torricellian-experiment : which , saith he , proceeds from something ( that is at a stress ) within the tube , and from nothing that is at a full and free liberty without : this suction and attraction of the finger he proves to be not onely eminently sensible in tubes above the standard ( whether open at both ends , or closed at the one ) but also in tubes under the standard of . inches : for , saith he , take a small tube , under the standard , open at both ends , of . inches supposed in length , and fill it with quicksilver , stopping the lower orifice with your thumb , then closing the upper with your finger , and immerging the lower into restagnant quicksilver ( as in the torricellian-experiment ) you shall ( saith he ) upon removal of your thumb ( though no quicksilver fall out ) feel a palpable suction of your finger , and the tube will stick so close to the pulp of your finger , that you may quite lift it out of the vessel , and carry it ( with all the quicksilver pendent in it ) up and down the room . therefore ( saith he ) the internal cylinder of quicksilver in the tube is not held up by the preponderant ayr without ; for , if so , whence comes so strong a suction , and so firm an adhaesion of the tube to your finger ? for if the external ayr thrust the quicksilver upwards , it can never at the same time draw down the finger too . his second argument , that the standing quicksilver in the tube , is not held up there by the external ayr , is fetch'd also from another experiment in the same tube : for ( saith he ) fill the same tube almost full of quicksilver ( leaving a little space of ayr within it ) and then immerging it as before , you shall see the quicksilver to make a considerable descent in it , viz. as far as that little ayr could well be extended , also a strong introsuction of your finger as before : from whence he thus argues ; if the external ayr cannot hold up . inches of quicksilver ( as we here see ; ) how can it hold up . i pray you ( as in the torricellian-experiment ? ) this experiment , as appears by our mercurial-observations , we made many years ago . his third argument is from the non-gravitation of the mercurial cylinder : for , saith he , the quicksilver in that station ( viz. after it has fallen to its old standard ) is not all ponderous , as you may perceive by your finger to the orifice of the tube ; from whence , saith he , 't is plain , that the quicksilver is there suspended by that tenuous , but tenaceous , rope in the tube . his fourth argument is from the difficulty of suction of quicksilver up a tube , open at both ends , of what length soever ; through which , saith he , water is easily drawn up to the mouth : and why not quicksilver ? since here is nothing else required but the removal of the internal cylinder of ayr , which is easily done ( saith he ) by suction , as is manifest by the ascension of water , but cannot be performed in quicksilver ( which should as easily be thrust up ( to . inches at least ) by the superincumbent atmosphaere ) as the water which is repugnant to experience of the fire : he concludes , 't is not the external ayr that causes that effect , neither by its elasticity , gravitation , nor both . now for the positive arguments to avouch his principles by , he has none at all ; onely what he fetches à posteriori , from his commodious solution of difficulties , and salving the phaenomena better then others have done . for read him through , and you shall see he hangs so like a tumbler by this rope , that swing him which way you will , you cannot get him off ; though , i doubt not , but we shall prove his cord to be a mere rope of sand , and of his own twisting ; and reason will , sampson-like , break it easily in pieces . chap. xi . a confutation of this funicular hypothesis of linus ; by henry power , m ae . d r. object . . if you fill a tube of . inches in length ( as we have shewed you in experiment . ) except . inches ( which let the ayr supply ) and invert it , you shall perceive a greater protrusion of your finger by the erupturient quicksilver , than can possibly be imputed to the supergravitation of the quicksilver included in the tube : for , if the whole tube be fill'd with quicksilver , and inverted , it shall not make such a forcible pressure upon your finger ( as that cylinder of quicksilver and ayr does ) which can be imputed to no other cause , then the elasticity of the included ayr ; which , striving to dilate it self , detrudes the quicksilver ; and , when liberty is given , it forces it down much lower than its ordinary standard of . inches : which shewes , that there is no such thing as attraction in the ayr , but rather a contrary power of self-extending , and dilatation . now , i confess , this is but an argument quoad sensum , and therefore not so much to be insisted upon , because not mechanically demonstrable . object . . again , this is observable in all bodies , that are capable of extension , that still , as their extension is augmented or increased , so must the force or power be that extends them . as for example , in ropes or leather , the first inch of their forced extension is performed by a lesser power then the second inch would be , and that then the third , &c. now in the third of boyle's experiments , pag. . it is observed , that the sucker is as easily drawn down , when it is nearer to the bottom of the pump , as when it is much farther off ; which is contrary to the nature of forced extension , as is before delivered . object . . again , if ( according to linus ) the bladder's intumescency , in boyle's engine , did proceed from the forced extension of the ayr in the receiver ; then the first evacuation of the pump would extend the bladder more then the second , and that than the third &c. but the contrary is avouched by his fourth experiment , pag. . which proves against the funicular doctrine of linus , but neatly makes out the elasticity of the embladder'd ayr , which gradually increases , as the debilitated ayr in the receiver gives room for its expansion . object . . again , linus is refuted by the . experiment in boyle , which is an experiment of a four-foot tube , fill'd with water , and inclosed in the receiver ; by which he found that the water , included in the tube , did not at all subside after several exsuctions , till the elasticity of the included ayr was no longer able to support that cylinder of water ; but , according to linus , it should have subsided at the first exsuction , as well as the quicksilver did when the torricellian-experiment was included in the said receiver . object . . according to linus his principles , the mercurial standard should be the same at the top of any eminent hill , that it is at the bottom , especially if the temperature of the ayr be in both places alike ; but this is contrary to the experiments we tried at hallifax and pendle-hill ( as you may see in experiment . pag. . also experiment ii. pag. . ) where the coldness of the ayr was a disadvantage to our experiments ; and yet , for all that , you see how considerably the mercurial standard did vary . which objection linus has ingeniously confess'd to me himself ( when once i had the happiness to see him ) that he cannot as yet answer . object . . take a glass-tube above the standard , but of a small bore , ( that will not admit above a great pea , or cherry-stone ) let it be closed at one end , and fill this with quicksilver ( which you shall find no easie thing to do ; for i am sure we were a whole hour in filling one , and still were forced to thrust the quicksilver down into it with a small wire ) then reverse it very gently into a vessel of restagnant quicksilver , and after it has come down to its wonted standard , you may lift the tube out of the vessel , and carry it up and down with the quicksilver pendent in it ; which will neither fall out , nor rise up to the top , to fill up the reputed vacuity . now what sayes linus to this ? why does not his rope shrivel it self up , and pull up this mercurial cylinder in this tube , as well as in all others of a larger bore ? object . . take a glass-syphon a b , and having fill'd both legs with quicksilver , open the longer into the vessel'd quicksilver b ; the effect is , that the quicksilver in the longer shank will fall down to c ( its wonted standard ; ) but that in the short shank ad , being still close stopped with your finger , will remain full . now ( according to linus ) the funicle ac exercises the same power of pulling the mercurial surface a as c : and according to the principles of mechanick's , if cb be heavier than ad , it should pull over ad into the vessel b. and his answer ( which you may read , pag. . is nothing to the purpose ; for open the short end of the syphon into the vessel d , ( according to his salvo ) no quicksilver should still rise , because it is still as closely adherent to the vessel'd quicksilver , as it was before , to my finger ; and yet , upon experiment made , the quicksilver will rise all out of the vessel d , and go over a , into the vessel b. which experiment , as it confuteth his , so it clearly avouches our principles , of the elastical pressure of the external ayr upon the surface of the quicksilver in the vessel d , which forces it up to a , and so over into the vessel b. object . . we took an ordinary weather-glass ( this . octob. . ) ab , of about two foot in length , and carrying it to the bottom of hallifax-hill , the water stood in the shank at c , ( viz. ) . inches above the surface of the water in the vessel b , thence carrying it thus fitted , immediately to the top of the said hill , the water fell down to the point d ( viz. ) ¼ inch lower than it was at the bottom of the said hill : which incomparably proves the natural elasticity of the ayr. for the internal ayr ac , which was of the same power and extension with the external at the bottom of the hill , being carried to the top , did there manifest a greater elasticity then the mountain-ayr there did manifest pressure , and so extended it self further by cd , which it was not able to do at the bottom , because the valley-ayr there was of equal force and resistance to it : which experiment very neatly proves the elasticity of the ayr ( which linus would abolish ) as the torricellian-experiment ; which being carried to the top of the same hill ( differ'd ½ an inch ) did eminently prove the gravitation of the ayr. also about the end of january , . we went again to the top of hallifax-hill , with divers weather-glasses of several bores , heads , and shapes ; and found in them all a proportional descent of the water , as in the former experiment at the top of the said hill respectively to what it was at the bottom , with this observable , that in the greatest-headed weather-glass ( which included most ayr in it ) the descent of the water was greater , as being most depress'd , by the greatest quantity of the included ayr. chap. xii . experiments in capillary tubes and syphons . experiment . take a small capillary glass-pipe , or tube , open at both ends ; and dipping the one extreme perpendicular into the water , you shall see the water spontaneously arise to a competent height in the tube , with a quick and smart ascent . note first , that the inside of the pipe ought to be very clean , as well from dust , and little bubbles , as films of water , which will remain in the pipe , when the water is blown , or suck'd out of it . secondly , it must be perfectly dry from any other liquors which will not mingle with water , as oyl , &c. thirdly , if you moisten the pipe first with water , before you try the experiment , the ascent of the water will be more quick and lively . fourthly , that not onely water , but milk , wine , oil , and other liquors , except quicksilver , will likewise rise to a certain height in the said pipes . fifthly , after the water has risen to its standard-height , if you take it out of the liquor , it shall not fall out at all ; if you invert the pipe , the included cylinder of water will fall down also to the other extreme : also the deeper you immerge it in the vessel of water , the higher still will it rise in the pipe , still keeping its standard-altitude above the surface of the water in the vessel : also if you suck it above the standard , it will still fall back to its wonted altitude . sixthly , that not onely water , but milk , wine , oyl , and all other liquors , will spontaneously arise in the said pipes ; but with this difference , that the heavier the liquors are , the lower their standard is , and the slower is their ascent to it : thus you shall see oyl of tartar will not rise , by one third , so high as water ; nor oyl of vitriol by ⅓ so high as it ; which may alter more or less , according to the goodness of the said oyls . seventhly , now if you take out a pipe ( wherein in either of the said oyls has first risen up to its wonted standard ) and immerge the end thereof into a lighter liquor ( as water ) you shall see the oyl fall gradually out into the water , and the pipe gradually fill with water , and arise to its own standard ; which is higher a great deal than the standard of either of the said oyls , as is before delivered : the like will follow in syphons . eighthly , the smaller bore that your tube is of , the higher will your water arise ; yet we could never get it to arise to the height of . inches ( as mr. boyle mentions ) though we have attempted it in tubes almost as small as hairs , or as art could make them . ninthly , if the tubes be of the bore of an ordinary quill , or bigger , no water at all will arise . tenthly , that little or no difference of the water's ascent in the former tubes is perceptible at the bottom , or top of our hill. experiment . bend one of these tubes into a little syphon ( which you may do by putting it into the flame of a candle ) and then putting the one extreme thereof into a vessel of water , you shall see it presently fall a running on its own accord . observe , . that the perpendicular height of the flexure of the syphon to the water's superficies , be shorter , or at least exceed not that standard-height , unto which the water would rise , were it a streight pipe onely . . that the pendent shank hang not onely lower then the water's superficies , but by such a determinate length ; for we have found , that if the pendent , or extravasated leg be shorter , or equal , or but a little lower then the superficies of the water in the vessel , no effect at all would follow ; but the pendent leg would hang full of water , without any flux at all . now what this determinate length is , we conceive the pendent shank must be longer from the flexure then the standard of the liquor would reach ; and then it will run as other syphons do which have a larger bore : so that you see , the mechanical reason ( which is so universally received by all men ) why the pendent leg in syphons must be longer than the other , to make the liquor run out ( viz. ) because the greater weight of water in the pendent leg , overpoises and sways down that in the shorter , as in a pair of skales ; is not universally true in all syphons whatsoever . . if to the nose of the pendent leg you apply a wet piece of glass , the water then will begin to come out of the pipe , and run down to the lowermost edge of the glass ; where , gathering it self into round bubbles , it would fall to the ground : but then you must observe that the nose of the pendent shank be lower than the surface of the water in the vessel . experiment . let both shanks of the syphon be fill'd with water , so that the pendent leg be longer than the superficies of the water ( and yet not so long neither as to set it on running ) then to the nose of the pendent leg apply a vessel of milk , and you shall see , that though the water would not break out of the pipe into the open ayr ( a medium far lighter , and more divisible than milk ; ) yet it did run out into the milk , and one might see it purl up again without mingling with the milk , at a little darkish hole , like a spring . observe : experiment . if you lift the vessel of milk ( with the pendent leg drown'd in it ) higher towards the flexure of the syphon , so that the superficies of the milk be nearer the flexure of the syphon than the superficies of the water , you shall ( after a considerable time ) see the milk rise up the pendent leg , and to drive back the water ; and having fill'd the whole syphon , to fall a running into the water-vessel , with this difference to the former experiment , that whereas the water in the former came to the top of the milk , the milk here sunk down to the bottom of the water , in a small stream like a curl'd white thread , and there setled in a region by it self . experiment . now , contrariwise , if you lift the vessel of water nearer the flexure of the syphon than the superficies of the milk is , then will the water rise over the syphon and beat out the milk , and fall a running , as in the third experiment . and thus you may at pleasure change your scene , and make the syphon fall a running , either with milk or water : which is a pleasant spectacle to behold , especially if the water be ting'd red with scutchenel . my worthy and ever honoured friend , mr. charles townley , upon confidence of these experiments , thought he had discovered that great , and long sought-for rarity amongst the mechanicks ( viz ) a perpetual motion : for the demonstrating of which , he devis'd this following experiment . m r. charles townley his experiment ; from which , he would deduce a perpetual motion . let the glass def be fill'd with two several liquors , so as they may remain in two distinct regions , one above another , as ab , without the least mixture ; ( which may be performed in milk and water , placing a broad piece of cork , or bread , that will swim so upon the milk , which must be the lower , as a , being heavier than water , that it may receive the force of the water's fal when you pour it upon the milk : ) this done , and the cork or bread being taken out , hang the syphon acb , first fill'd with milk , upon the stick dce , so artificially , that the longer end a may remain in the region of milk , and the shorter end b in the region of water ; with this caution , that the flexure of the syphon c be removed no higher from the milk , than it would naturally ascend to , if the syphon was streight : now ( saith mr. charles ) since in the former experiment the water would rise over the top of the syphon , and drive back the milk ; and afterwards rise to the top thereof , and there swim aloft : why here in the syphon acb , the like should not follow , ( viz. ) the water at b drive the milk , ( which is suppos'd first to fill the syphon ) back to c , then to a , where issuing out of the pipe ( as it did in the former experiment ) it would ascend to its proper region of water again , and so continue in a circular motion perpetually . now however this same problem of m. charles might seem probable in the theory , yet it will prove more than most difficult ( if not impossible ) in the practice . for , . we fill'd the glass def , half full of milk , and half full of water , as ab ; then hanging the syphon ( first fill'd with milk ) so artificially on the stick de , so that the longer shank might reach the milk a , and the shorter might open into the superincumbent region of water b , we observ'd this effect , that the milk did for a small time run out of the orifice b , and seem'd to fall into the inferiour region of milk ; but at last the milk ( or at least the serous or more watrish parts thereof ) so intermixed with the water ( which we could discern by the whiteness and opacity of the water ) that the flux was quite stifled . . contrary to mr. charles his prognosticks , the water did not rise up the short shank , and drive back the milk , but quietly permitted the milk to drill through it ; though i know it was not material which way the flux was performed , provided it would have been perpetual . the experiment failing in these two liquors , we attempted the same again in other two liquors ( which we were sure would not mix ; ) and to that purpose we fill'd the aforesaid glass with oyl of tartar per deliquium , and spirit of wine , which we tinged yellow with saffron , the better to distinguish the liquors ; and then adapting the syphon , as before , we wish'd for a happy event in the experiment . but experience ( which ought to be the mistress of wise men as well as fools ) shew'd us the quite contrary ; for the syphon would not run at all , but continued full , which we afterwards conjectured to proceed from the heterogeneity of the two liquors ▪ so that the oyl of tartar would not break out into the spirit of wine , no more than milk or water will do into the open ayr , where the pendent shank is shorter than the standard-height of those two liquors . so that , it seems , to effect this experiment indeed , two such liquors must be found out , as are in some wise homogeneous , and of a congruity , and the one considerably lighter than the other , which is tantùm non impossibile . for besides the former liquors , we have tried oyl and water , and no motion at all was perceived , for the same reason of incongruity formerly delivered . but these , and a hundred more experiments of this nature are every day excogitated and tried by our noble society of gresham-colledge , which in a little time will be improved into far nobler consequences and theories , than can possibly be done by the single endevours of any person whatsoever . the end of the mercurial experiments . experimental philosophy . the third book . containing experiments magnetical : with a confutation of grandamicvs . amicus , plato ; amicus , aristoteles ; grandis amicus , grandamicus : sed , magis amica , veritas . by henry power , d r. of physick . london , printed in the year . a confutation of grandamicvs his magnetical tractate , de immobilitate terrae . the third book . chap. i. the three great demonstrations and magnetical discoveries that this authour so gloriously pretends to , are . a magnetical demonstration of the earth's immobility . . an universal meridian magnetically demonstrated . . a magnetical discovery of longitudes , or something equivalent thereunto . in the canvassing of these three great discoveries , we shall invert the order , and begin with the last first . but before we can conveniently fasten upon these three main pillars of his book , there are three other considerable errors of his , first to be removed ; which , though they lye more obscure and removed from our sight , and buried , as it were , under ground ; yet indeed are they the basis and foundation upon which his magnificent structure is built : and they are these positions following : . that the virtue of the magnet , and all magnetick bodies , is purely immaterial , and a bare simple quality . . that it proceeds intrinsecally from the proper form of the loadstone ; as he hath delivered , cap. . pag. . . that all the world , and consequently all the bodies therein , were made , by the divine providence , for the use of us and our habitation , this globe of earths which he has fixed in the centre of the world , and constituted us lords and masters of all the universe . grand . pag. . chap. ii. of the corporeal effluviums of the loadstone . doctor highmore tells us , that the magnetical exspirations of the loadstone may be discovered by the help of glasses , and be seen in the form of a mist , to flow from the loadstone : this , indeed , would be an incomparable eviction of the corporeity of magneticall effluviums , and sensibly decide the controversie under consideration . but i am sure he had either better eyes , or else better glasses than ever i saw ( though i have look'd through as good as england affords ) and the best of them all was as far from presenting these subtil emanations , that they would never exhibit to me those grosser , and far more material , effluviums , from electrical and aromatical bodies : nay , not the evaporations of camphire , which spends it self by continually effluviating its own component particles : nay , i could never see the grosser steams , that continually transpire out of our own bodies , and are the fuliginous eructations of that internal fire which constantly burns within us . indeed , if our dioptricks could attain to that curiosity , as to grind us such glasses as would present the effluviums of the magnet ; we might hope to discover all epicurus his atoms , des-cartes his globuli aetherii , and all those insensible corpuscles which daily produce such considerable effects in the generation and corruption of bodies about us : nay , might not such microscopes hazard the discovery of the aerial genii , and present even spiritualities themselves to our view ? but though both our natural and artificial eyes fail in this performance , yet have we another more intrinsick eye , that will yet discover their materiality , and that is the piercing eye of reason . for , . that the magnetical emissions and fluors , are not bare qualities , but indeed corporeal atoms , is deducible from hence ; that this virtue decayes in progress of time ( as all odours do ) and is totally destroy'd by fire in a few minutes , and is capable of rarity and density , whence it is more potent near at hand than further off : all which are the proper and incommunicable attributes of bodies . . again , it is further evinced by some parallel and analogical effects of electrical with magnetical bodies , that they both work by corporeal effluviums ; for a well polish'd stick of hard wax ( immediately after frication ) will almost as vigorously move the directory needle , as the loadstone it self ; onely there is ( amongst others ) these considerable differences 'twixt these eminent bodies , that the effluviums of the one , ( as being more gross and corporeal ) are intercepted by any medium ; but magnetical effluviums are hindred ( because of their exceeding tenuity ) by the interposition of no body whatsoever . secondly , whereas electrical fluors do presently recoyl by short streight lines to their bodies again , magnetical atoms do not so ; but do wheel about , and , by a vortical motion , do make their return unto the loadstone again , as des-cartes hath excellently declared . chap. iii. that the magnetical effluviums do not proceed intrinsecally from the stone , but are certain extrinsecal particles , which approching to the stone , and finding congruous pores and inlets therein , are channel'd through it ; and having acquired a motion thereby , do continue their current so far , till being repulsed by the ambient ayr , they recoyl again , and return in a vortical motion , and so continue their revolution for ever , through the body of the magnet . argument . this seems probable , first , from this , that if a magnet it self be made red hot in the fire , it not onely amits the magnetical vigour it had in it self before , but acquires a new one , according to the positional laws in its refrigeration ; so that by inverting the extremes ( as it came out of the fire ) you may alter the poles thereof ( at pleasure , ) nay , you may change the polarity of many feeble stones , by a long position , in a contrary posture to that which it naturally affects . both which experiments seem to shew , that the magnetical effluviums are not innate and congenial to the stone , but proceed ab extrinseco , &c. therefore do impregnate the stone again , upon their re-admission ; or do change its polarity , as the more powerful streams of atoms do prevail . the like experiment ( if it could be tried ) would doubtless hold good in the great magnet of the earth ; for the terrella we see in all other phaenomena , is avouched by her mother-earth . argument . the said argument we may assume from a certain section of the stone ; for if you divide the magnet through a meridian , or saw of a segment , parallel to the axis , the former axis and poles will quite vanish away ; and each segment , by this division , will acquire a new axis of its own : which shews , that the external magnetical fluors , which pass'd through the stone , all in one continued stream before , now passe by several currents through both stones , and so create a new axis and poles in either . argument . is from the disponent or directive faculty ( as they call it ) of the stone ; for to say , this polary direction proceeds from it self , is to put a soul , or intelligence , at least , into the stone ; which must turn it about ( as angels are fained to do the coelestial orbs : ) how much more credible is it , that the stream of atoms from without , by beating upon the stone , do turn it to and fro , till they have laid it in such a position as is fittest for them to run through it , as a stream of water turns a hollow trunk of wood , or a long stick , till it come to lye parallel to its current . argument . is from the different effects proceeding from all effluxions that come from all other bodies , besides magnetical , as electrical , odoriferous , &c. for all bodies that effluviate intrinsecally from themselves , their exspirations flye quite away into the open ayr , and never make any return again to the body from whence they proceeded , so that in time they do not onely spend their quintessential and finer particles , but even their whole bulk and substance , as is ocularly manifest in camphire : now 't is not so in magnetical bodies , whose exspirations are continual and permanent , because they return in circumgyrations to their bodies again . argument . if the magnetick rayes proceeded intrinsecally from the stone , there is most reason they should proceed from the centre , the stone being all of an uniform substance ; as the luminous rayes doe from the body of the sun , and as odours do from their original ; and so there would be no poles , nor inclinations of magnets more in one latitude than in another : but now since there are two poles , where the current of effluxions are strongest , it is a sign the magnetical fluors coming from without , doe strike a stream in at one pole ; and finding the grain and bait of the stone , to lye fit for their tranation , do channel through to the opposite part of the stone , and so continue their current in the ayr , so far , till they are resisted and forced to recoyl by a double whirlpool-motion round about into the magnet again . argument . that the magnetick fluors proceed not intrinsecally from the stone , to cause the self-direction in the magnet , is further evident from this new experiment : take a wedge of iron ( which the smiths call puncheons ) and heating it red-hot , you shall , according to the laws in its refrigeration , endue it with a polary verticity , as has been praeobserved by all magnetick writers : but that which will heighten the experiment further , is , that though it hath but acquired a feeble virtue by its refrigeration , yet if you take it up cold , and with a few smart strokes of a great mall , or hammer , you beat the one end of it , setting the other against some hard resisting matter , as stone , brass , iron , or hard wood , you shall thereby give it a most powerful magnetisme , so that it will then as actively move the needle , at a good distance , as the loadstone it self : now , say i , by those percussions you did so open and relax the pores in the iron-wedge , that the magnetical atoms could then enter in , with a full carriere , which before they could not ; and having once got so free a passage , they will maintein the current ever after . argument . since a constant , steddy , and polary direction of parts is onely observable in bodies magnetical , we have reason to think and believe , that these magnetical effluvia ( which are the cause of this peculiar direction ) are not only transmitted and channel'd through the earth , but through many other coelestial bodies also , as ☉ ☽ ♃ ♄ , and , perchance , the rest of the planets yea and fixed stars too , as by telescopical observations is now made very manifest in those bodies that swim within our planetary systeme . argument . take a rod of iron ( or a puncheon ) as before ; heat it red-hot , and according to the laws in its refrigeration , you may endue this or that extreme with whether polarity you please ; now afterwards by striking it with a hammer in the same posture that it was cooled in , you may much advance and invigorate its magnetical virtue , as we have formerly declared : but now the main observable of all , is , that after both the reception of the virtue by convenient refrigeration , as also the augmentation of it by percussion , you may by inverting and repercussing the extremes , alter the polarity of the iron at your pleasure ; and then , which is stranger , that if you strike the iron in the middle 'twixt the two extremes , it will destroy its formerly acquired magnetism . argument . if you bore with a wimble in any hard piece of wood , till you heat it soundly , you will communicate to it a strong verticity , insomuch that it will nimbly turn a magnetical needle ; but if with a dril of iron or steel you bore a piece of brass or iron till you heat it well , it will acquire so strong a magnetism thereby , that it will not only turn an equilibrated needle , but vigorously attract , and lift up a small needle : and i have observed the small filings and shavings which fall out of the drill-hole , to stick to the point of the drill , as if it had been to a magnet it self ; which shews , that the magnetical atoms did more easily by far enter into the drill or wimble , when the parts thereof were heat and set in motion , than before . which still seems to make out , that the magnetical atoms rather enter into , than proceed from those bodies we call magnetical , as the reaching soul of the renowned des-cartes hath happily supposed . chap. iv. that the world was not made primarily , nor solely for the use of man , nor in subserviency unto him and his faculties . as i would not derogate from the greatness and eminency of man ( as being a very noble creature ; ) so i would not have him arrogate too much to himself : for though it may be a pious , and morally good conception , to think that the whole world was made for him , yet i am sure 't is no real and physical truth . for first , how many glorious bodies of vast bulks , and immense distances , have appeared , nay , and may yet appear to future ages ( as comets and new stars ) which are now gone and vanish'd again , which no mortal man ever understood the reasons and causes of , nor received no good nor evil , either before or since their appearances ? nay , how many such comets may have been near the sun , whose first rise , continuation , and disappearance may have been made in six moneths time , of which ( by reason of the sun's vicinity to them ) we could never see nor know any thing ? who can be so irrational , as to think that those innumerable company of stars ( with which the via lactea is powdred ) and many other parts of heaven are throng'd ( as the pleiades ) in which very subconstellation i have seen above . stars of a considerable magnitude , and lesser ones innumerable , also the hyades , the stellae nebulosae , &c. were ever made for the use of us and our earth , since they are at that immense distance , and invisible to our eyes ; and had remain'd eternally so , had not the incomparable invention of telescopes relieved our eye-sight herein ? nay , to come nearer , who can imagine that any of the primary planets were wholly designed for the service of us and our earth ; whereas , if most of them were pluck'd out of the heavens , we should no more feel the want of them , than the countrey swain that already knows of no such wanderers ? what then must we think of the secondary planets , as the circum-saturnian , and the four jovialists , which are not onely indiscernable by us , and therefore were never designed for our use , but also have their peculiar motion about their primary planets ( which they orderly and punctually attend ) which shews other ends that god and nature has designed them for , to wit , to be as wholly subservient to their central planets of saturn and jupiter , as the moon is to us ? lastly , who is there that knows not the vast disproportion 'twixt this speck of earth , and the immense heavens , how that it is less than the smallest mote or atom , which we see to hover and play in the sun's beams , in comparison of the fixed stars ? so that if one stood but in the firmament , it could never be seen at all ; and if it were annihilated , would never be miss'd , being so small and inconsiderable a portion of the creation : nay , our modern philosophers have found , that not onely the earth , but the whole orbis magnus ( which is the earth's annual circle it describes about the sun ) is but a point , in regard of the immense distance of the fixed stars . nay , the noble and elastical soul of des-cartes , that has stretch'd it self yet a pin higher , has done the heavens and upper world more right yet , as to the magnificent vastness of its expansion , and has shown us that every fixed star is a sun , and is set in the centre of a vortex , or planetary system , as ours is , and that they are as far remote one off another , as ours is off them ; and that all our whole planetary vortex shrinks almost into nothing , if compared to those innumerable systems above us . what are we then but like so many ants or pismires , that toyl upon this mole-hill , and could appear no otherwayes at distance , but as those poor animals , the mites , do to us through a good microscope , in a piece of cheese ? let us not therefore pride our selves too much in the lordship of the whole universe , 't is more , i am sure , than we could challenge from our creatour , that he hath made us such noble creatures as we are , that he hath given us such a large inheritance , as the whole globe of the earth , that he hath subjugated all things therein to our use and service ; and lastly , that he hath endued our souls with such spiritual and prying faculties , that we can attempt and reach at the superiour and more mysterious works of his creation , and therein to admire those things we are not capable to understand . as for the earth being the centre of the world , 't is now an opinion so generally exploded , that i need not trouble you nor my self with it . and , indeed , what need i take pains to refute that which is but gratìs dictum , and which he neither hath , nor all the peripateticks in the world can ever prove . let us first see him do that , and then you shall see what i am able to say to it . chap. v. and now i come to his three great inventions ; and the first shall be of longitudes . to find the longitude of any place , or some thing aequipollent thereunto , is easily done ( saith he ) from these three data ; that is , the angle of magnetical inclination . magnetical variation . elevation of the pole. as for example : at rouen in france , the angle of north-easting variation of the compass is gr . ' the angle of septentrional inclination is gr . the elevation of the north-pole there , is gr . grandamicus his consequence from hence . now 't is impossible ( saith he ) that these three angles should be the same in any other determinate point of the earth , but at our city at rouen . to which we reply , first , that he runs upon a false assumption ; viz. that the angle of variation it self is perpetually the same in the same place of the earth , which is false ; for mr. burrows , ann. dom. . made an exact observation of the needle 's variation towards the east at lime-house , near london , and found it to amount to no less than gr . ′ , and afterwards , ann. dom. . mr. gunter , at the same place , observed it to be diminished to onely gr . and ′ . and gildebrand , ann. dom. . in the same place found it to come yet lower , and not to exceed gr . min. so that in process of time it is very probable it will come to an exact meridionality , and , perchance veer as much on the other side of the meridian line ( viz ) westwards , as it hath done of this . doctor croone , my worthy and most ingenious friend , writes me word , that in june last , . the magnetical variation at london , was found to be by the best observation ′ ″ westwards : so that it seems it has past the meridian already . and of this mystery of the variation of the variation , grandamicus himself was not ignorant ; but because it would spoyl his glorious invention , he therefore unhandsomly and unworthily asperses our english observations , with ignorance , error , and incertitude , cap. . pag. . whereas the observators nominated , were of that knowledge and perspicacity in the mathematicks , that i am sure 't is a credit to grandamicus to be inferiour to any of them . but we shall now tell him , that not onely the english , but his own countrey-men have found out this truth . so that the like decrease of the needle 's variation has been observed at paris by mersennus , and at aix by gassendus : so then this angle of variation being quite fallible , and alwayes variable , his other two angles will prove nothing at all ; for they are the same in the same latitude or parallel round about the earth . . but granting him his three data : i say , in the opposite point of the globe ( that is antipodes to rouen ) all these three angles are the same . if you reply , and say , that though the angles of variation and inclination be the same , yet they will be pointed out by the opposite points of the directory and inclinatory needles . to which we counter-reply , that the same point of the needle that pointed at the north-pole here , will there point at the south-pole ; therefore he can have no evidence of the needle of variation , as is manifest by carrying the needle from the one pole of the terrella to the other . and for the inclinatory needle , we see what a ticklish thing it is to make exactly , and though it be poized by a good artificer , yet will it miss one or more degrees in hitting the true point of inclination , which would be a considerable error , to a land-traveller at least . . for the profit and utility of this invention , 't is none at all : for to a traveller that sails in one and the same parallel ( which he may do many a thousand miles ) the angles of inclination and elevation will remain the same with those at the port from whence he set sail ; and though the angle of variation did alter ( as he would have it ) yet my marriner can tell nothing at all thereby , but onely thus , that he is not at rouen ; but how far he is gone from it , either east or west , he knowes not at all ; unless he foreknew the angles of variation in every longitude , which is yet unknown : and if they were all now known , yet were it of little or no use or benefit , because in process of time the variation it self varies , as we have pre-observed . chap. vi. and now we come to his second great invention , with which he thunders against the copernicans , and that is his great magnetical experiment to avouch the earth's immobability . to this experiment therefore drawn from the perpendicular position of the magnet , we answer , that the reason why the terrella does wheel about , and direct certain parts of its aequator , to certain and determinate points of the horizon , is , because it is overpower'd by the magnetical effluxions of the earth ; which , as a greater magnet , does violently reduce it to that situation , which probably is the same that those aequatorial parts had in their mineral beds : and therefore this great argument against the dinetical motion of the earth , is no argument at all , unless that he could prove to us that the terrella could play this trick ; it were removed out of the sphaere of the earth's magnetisme , which is beyond his philosophy ever to demonstrate . . again , if this motion of the magnet did proceed from an intrinsecal tendency that it has of its own , to bring all its parts to their right and determinate points , there to remain in a perfect stability , then would those parts constantly affect this ( and no other ) situation , howsoever the loadstone was posited ( provided it be at liberty to move it self to its desired position . ) but this is false ; for , in grandamicus his experiment , if you invert the poles of the magnet , and set the north-pole in the zenith , and the south in the nadir , you shall see the stone to counterchange its situation , and those aequatorial parts of the magnet , which before respected the east , shall now wheel about , and fix themselves in the west ; and the northern parts turn to the south : which shews , that the stone does not tack about from an intrinsecal principle and form of its own , but is turned by the extrinsecal effluxions of the whole earth ; or rather by the stream of those magnetical atoms , that strike not onely through the axis of the earth , but also through the body of every petty loadstone , accordingly as they are best received by the grain or bait of the said stone . and now i am engaged in this magnetick discourse , i must tell you that i think our famous gilbert has drawn a more prevalent argument from this magnetical philosophy , to prove the earth's motion by , than grandamicus has done to destroy it ; for since it is demonstrated of late , that all the whole earth is nothing but a great and globular loadstone , and that all the circles of the armillary sphaere , are really , truly , and naturally inhaerent in the earth , by virtue of the transcurrent atoms , how can we conclude otherwise but with gilbert ? quis in posterum eum de facto moveri dubitabit , quum ei omnia ad motum planè requisita , dedit natura ; i. e. figuram rotundam , pendulam in medio fluido positionem , & omnes terminos motui circulari inservientes , polos nempè , aequatorem , meridianos & polares circulos , & parallelos ? lastly , as for his universal meridian , it is likewise deduced from his anti - copernican experiment of the loadstone swimming in a boat , with its poles vertically erected : for ( saith he , ) since the stone being horizontally-placed , does not shew the true meridian , but with an angle of variation , in most , if not in all places of the earth , if you set it with its axis perpendicular as before , it will ( after some undulations to and fro ) rest quietly , with certain parts facing the meridian ; which points must be exactly marked , and through them a circle drawn round about the stone ; by help of which , you may strike a true meridian-line , when and where you please . now , though we grant this experiment to be true , and , probably , to hold good in all longitudes and latitudes ; yet he that shall perpend ▪ how many ticklish curiosities , and nice circumstances there are to perform this experiment exactly , will find the invention only pleasing in the theory , but not in the practice : for , . it is very difficult to place the terrella in an exact perpendicular ; . when 't is so , 't is as difficult to keep it invariable under the same zenith ; . most difficult to draw an exact meridian-line from it : not to mention how hard a thing it is ; first , to find the two polary points in a globe-loadstone ; also to keep the boat in a fluctuation , parallel to the horizon . the end of magnetical experiments . subterraneous experiments : or , observations about cole-mines . by henry power , m ae . d r. a the cole-pit . b the vent-pit . cc the sow , that drains all the heads from water . ddd , &c. the vent-head , not above two yards broad . eeee the lateral heads , which are not above two yards broad . fff the prick'd lines , the thurl-vent ; that is , a vent driven through the lateral heads . gggg is walls or pillars of the whole cole-bed remaining ( which with us is not above two foot thick ) to hinder the roof of the pit for falling . the roof and seat is the top and bottom of the works , wherein they get coles , which is about two foot or more distant the one from the other . experiment . at the top of the cole-pit we took the weather-glass ab , whose shank eb was about ½ foot long , of a small bore , and the head ae ● / ● inches in diameter ; and heating the head thereof , and immerging it presently in the glass ful of water b ; the water , after a competent time , rose up to the point c ; where we let it stand for a while , till we saw that the external and internal ayr were come to the same temper and elasticity . then carrying the weather-glass ( so prepared ) in a scoop down to the bottom of the cole-pit ( which was not above . yards deep ) there the water in the weather-glass did rise up to the point d , viz. very near . inches higher than its former standard c. experiment . the sixth day of november , . we repeated the same experiment , as before , in a pit of . yards deep , and there we found , that at the bottom of the said pit the water in the weather-glasse , did rise very near four inches higher than the point c : viz. one inch higher than the point d to f. now we observ'd , that in carrying down of the said glass in a scoop from the top to the middle of the pit , there the water did not rise so much as it did from the middle to the bottom , by half an inch ; so that it seems the rise of the water was not proportional to the glasse's descent in the pit. experiment . we took a very good arm'd loadstone , of an oval figure ( whose poles lay in the long diameter ) and at the top of the coal-pit we loaded the north-pole of it with the greatest weight it was able to carry , even to a scruple ; then taking the stone down to the bottom of the pit , and hanging on the same weight again , we could perceive no difference in the power of the stone at the one place from the other ; for it would neither lift more nor less there , than above : though to try this experiment precisely , and to minute weights , is very ticklish ; for the same stone in any place will sometimes lift a little more , and sometimes a little less . experiment . we took a thread of . yards long ( which is as long as the deepest pit is with us ) and fastening a brass lump of an exact pound weight to it , we counterpoiz'd both it and the thread with a weight in the other scale ; then fastning the other end of the thread to one of the scales , we let down the pendent weight near to the bottom , and there we found it to weigh lighter by an ounce at least than it did at the top of the said pit . we had tryed this with a bladder full of water , and other substances also , but that our thread by often untwining broke it self . experiment . the collyers tell us , that if a pistol be shot off in a head remote from the eye of a pit , it will give but a little report , or rather a sudden thump , like a gun shot off at a great distance ; but if it be discharg'd at the eye of the pit in the bottom , it will make a greater noise than if shot off above-ground . but these experiments are of a dangerous trial in our pits , and the collyers dare not attempt them by reason of the craziness of the roof of their works , which often falls in of its own accord without any concussion at all . every cole-pit hath its vent-pit digg'd down at a competent distance from it , as . or . paces one from another . they dig a vault under-ground from one pit to another ( which they call the vent-pit ) that the ayr may have a free passage from the one pit to the other ; so that both pits with that subterraneous intercourse , or vault , do exactly represent a syphon invers'd . now the ayr always has a motion , and runs in a stream from one pit to the other ; for if the ayr should have no motion ( or vent , as they call it ) but restagnate , then they could not work in the pits . it is not requisite that the vent-pit should be as deep as the cole-pit . now the vent , or current , of subterraneous ayr is sometimes one way , and sometimes another ; sometimes from the vent-pit to the cole-pit , and sometimes contrariwise ( as the winds ( above ground ) do alter ; ) and also weaker and stronger at sometimes than at others : and sometimes the vent plays so weakly , that they cannot work for want of ventilation . then to gather vent ( as they call it ) they straiten the vault , and wall part of it up ; so that the ayr ( which before run in a large stream ) being now crowded into a lesser channel , and forced to pass through a narrower room , gathers in strength , and runs more swiftly . now it is observ'd , that the subterraneous ayr is alwayes warm , and in the coldest weather , the warmest ; so that it never freezes in that pit , out of which the vent plays . of damps . there are three sorts of damps , or rather three degrees of the same damp ; viz. the common . viz. the suffocating . viz. the fiery . the common damp is that subterraneous steam , or exhalation , which coming out of the earth , restagnates in the heads and undergroundy-cavities , and hinders their candles for burning , so that they cannot work . . if they incline their candle downwards , towards their seat , it is observ'd , it will abide in the longer , and not sweal away , and stifle it self with too much tallow , as it would do above-ground . . though this damp be so great , as it extinguishes the candle , yet they can abide in it without suffocation . also the heavy vapour will restagnate there , and is not able to rise . . this damp is sometimes generated by the effluviums and perspirations that come out of their own bodies that work , if they sweat much ; and if the candle be within the sphaere of those effluviums , it will extinguish it as the former ; as the collyers observe that pass from one head to another that is working in another head . this damp is sometimes on the one side of the heads and not on the other ; and for the most part it runs all along the roof , so that a candle will burn , if set upon the seat : but if you lift it up into the superincumbent region of damp-vapours , it will be immediately extinguish'd . now besides the playing of the vent , they sometimes are necessitated to keep constant fires under-ground , to purifie and ventilate the ayr : sometimes the running of the scoops ( when they begin to work ) will set it into motion : sometimes , if the damp draw towards the eye of the pit , then they set it into motion by throwing down of cole-sacks . of the suffocating damp. the suffocating or choking damp is a more pernicious exhalation , or else a higher degree of the former ; into which no man is able to enter , but presently he is stifled and dyes . and it is observed , that the bodies of those ( which are so slain ) do swell , and are puffed up exceedingly , as if poyson'd . this damp is seldom here in our pits ; but if it be , then the first person that is let down into it , is presently kill'd : so that afterwards they try , by letting down dogs , when it is removed , and fit to enter into ; and most-part by letting down of lighted candles , which will be extinguish'd by the damp in the bottom of the pit , if any damp be restagnant there . of the fiery damp. the fiery damp is of all others the most dangerous , but is never seen in our pits , though in pits at leeds , which is not above . miles off , as also in the lancashire pits , and newcastle pits , i have heard much of it . it is a vapour , or exhalation , which comes out of the mineral , or out of the clifts in the mineral , and it sometimes comes out fired , and sometimes in the form of a smoke , which afterwards fires of its own accord , and then forces its way with that vehemence and activity , that it drives all away before it , and kils without mercy ; insomuch that i have heard , that not many years ago , three men in newcastle-pits were so shattered with it , that their very limbs were sever'd . this fiery meteor is observ'd to run all along the roof of the pit , so that if the collyers have the fortune to see it issuing out , there is no way to secure themselves , but to lye flat along to the seat of the pit , and so do sometimes escape so great a danger . sometimes it has taken its way up at the pit-eye , or shaft , with such vehemency , that it has thrown the turn quite away from the mouth of the pit , which is a cylinder of wood of a great weight , and has burnt and sindg'd the rope , as black as lightning does trees . this is that meteor , certainly , that paracelsus calls the coruscation of metals , which , he sayes , is a sign of metals in that place ; and , doubtless , is it that occasions earthquakes , whensoever it happens in any quantity , and can have no vent . the end of subterraneous experiments . the conclusion . to the generous virtuosi , and lovers of experimental philosophy . certainly this world was made not onely to be inhabited , but studied and contemplated by man ; and , how few are there in the world that perform this homage due to their creator ? who , though he hath disclaimed all brutal , yet still accepts of a rational sacrifice ; 't is a tribute we ought to pay him for being men , for it is reason that transpeciates our natures , and makes us little lower than the angels : without the right management of this faculty , we do not so much in our kind as beasts do in theirs , who justly obey the prescript of their natures , and live up to the height of that instinct that providence hath given them . but , alas , how many souls are there , that never come to act beyond that of the gazing-monarch's ? humanum paucis vivit genus . there is a world of people indeed , and but a few men in it ; mankind is but preserv'd in a few individuals ; the greatest part of humanity is lost in earth , and their souls so fixed in that grosser moity of themselves ( their bodies ) that nothing can volatilize them , and set their reasons at liberty . the numerous rabble that seem to have the signatures of man in their faces , are brutes in their understanding , and have nothing of the nobler part that should denominate their essences ; 't is by the favour of a metaphor we call them men , for at the best they are but des-cartes's automata , or aristotle's 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , but the moving frames , and zanies of men , and have nothing but their outsides to justifie their titles to rationality . pugs and baboons may claim a traduction from adam as well as these , and have as great a share of reason to justifie their parentage . but it is not this numerous piece of monstrosity ( the multitude onely ) that are enemies to themselves and learning ; there is a company of men amongst the philosophers themselves , a sort of notional heads , whose ignorance ( though varnish'd over with a little squabling sophistry ) is as great and invincible as the former . these are they that daily stuff our libraries with their philosophical romances , and glut the press with their canting loquacities . for , instead of solid and experimental philosophy , it has been held accomplishment enough to graduate a student , if he could but stiffly wrangle out a vexatious dispute of some odd peripatetick qualities , or the like ; which ( if translated into english ) signified no more than a heat 'twixt two oyster-wives in billings-gate : nay , these crimes have not onely stain'd the common , but there are spots also to be seen even in the purple gowns of learning . for it hath been a great fault , and , indeed , a solemn piece of folly , even amongst the professors and nobler sort of philosophers , that when they have arrived to a competent height in any art or science , if any difficulty do arise that their art cannot presently reach unto , they instantly pronounce it a thing impossible to be done ; which inconsiderable and rash censure and forestallment of their endevours , does not onely stifle their own further enquiries , but also hangs , to all succeeding ages , as a scar-crow to affright them for ever approching that difficulty . hence it is , that most arts and sciences are branded at this day with some such ignominious impossibility . thus came they to upbraid chymistry with the altahest , and philosophers-stone ; geography , with longitudes ; geometry , with the quadrature of a circle ; stereometry , with the duplication of the cube ; trigonometry , with the trisection of an angle ; algebra , with the aequation of three discontinued numbers ; mechanicks , with a perpetual motion ; and our own profession , with the incurability of cancers and quartans . nay , the spring and nepetides in natural philosophy , the doctrine of comets in astronomy , the terra incognita in geography , the heart's motion in anatomy , the forming of conick sections in dioptricks , the various variation in magnetical philosophy , are accounted as insuperable difficulties as the former , whose causes ( they say ) defie all humane industry ever to discover them . but besides this intestine war , and civil dissention that is 'twixt men of the same denomination and principles , there is one more general impediment , which is an authentick discouragement to the promotion of the arts and sciences , and that is , the universal exclamation of the world's decay and approximation to its period ; that both the great and little world have long since pass'd the meridian , and , that the faculties of the one doe fade and decay , as well as the fabricks and materials of the other ; which though it be a conceit that hath possess'd all ages past , as nearly as ours , yet the clamour was never so high as it is now : something , therefore , i shall here offer , that will abate and qualifie the rigour of this conception . an essay , to prove the world's duration , from the slow motion of the sun 's apogaeum , or the earth's aphelion . first , we take for granted , from the scripture-account , that the world is about . years old . secondly , we take it for granted , that the sun 's apegaeum was at the creation set in the first point of aries ; for which you will anon see prevalent reasons . thirdly , from astronomical observation 't is now found , that the sun 's apogaeum is about the sixth degree of cancer . fourthly , by intervals of observation it is likewise found , that the motion of the sun 's apogaeum , in . years , is gr . ′ ″ , which by retrocalculation will point out the time of the world's nativity to be about . years ago , which very handsomely draws nigh to the scripture-account , as the famous longomontanus has ingeniously observed . now in all likelihood , he that made this great automaton of the world , will not destroy it , till the slowest motion therein has made one revolution . for would it not even in a common watchmaker ( that has made a curious watch for some gentleman or other , to shew him the rarity of his art ) be great indiscretion , and a most imprudent act , and argue also a dislike of his own work , to pluck the said watch in pieces before every wheel therein had made one revolution at least ? now the apogaeum ( if it move equally , as it hath hitherto done ) will not perfect one revolution under . years , whereof there is but one quadrant yet spent , and . years are yet to come . besides , what reason is there that god should respect the one hemisphaere of the earth , more than the other ? for , take the sun 's apogaeum now as it is , and the north hemisphaere of the earth hath eight days more of the sun's company than the south hemisphaere hath ( as is plain to every one's observation ) for it is eight dayes more from the vernal to the autumnal aequinox , then it is from the autumnal to the vernal again ; which inequality will be repaid to our antoeci in one revolution of the sun 's apogaeum : for . years hence , both hemisphaeres will equally enjoy the sun 's illuminating presence ; and . years after that , the southern hemisphaere will have the eight supernumerary dayes transferr'd to them ; and then at the period of the last . years , both hemisphaeres will be equilibrated again : therefore , in all reason , those southern inhabitants may expect , and we must grant one revolution of the sun 's apogaeum , at least , ( which is . years ) yet to come , to ballance our felicities in this world ; and who knows , but it may be continued many more revolutions ? thus much for the macrocosm : now what decay there is in the microcosm , we must be both parties and judges ; and how far our modern wits have outdone the ancient sages , the parallel 'twixt the few inventions of the one , and the rare discoveries of the other , will easily determine . but the learned hackwell's apology shall be mine at present , for not treating any further of this subject ; he having long since perform'd that task , to the conviction of prejudice it self . besides this catholick one , there are other remora's yet in the way , that have been accessory hindrances to the advancement of learning , and that is , a diffidence and desperation of most men ( nay even of those of more discerning faculties ) of ever reaching to any eminent invention ; and an inveterate conceit they are possess'd with of the old maxim , that nil dictum , quod non priùs dictum : by which despondency of mind , they have not onely stifled the blossoming of the tree of knowledge in themselves , but also have nipp'd the very buds and sproutings of it in others , by blazing about the old and uncomfortable aphorism of our hippocrates , of nature's obscurity , the life's brevity , the senses fallacity , and the judgement 's infirmity . had the winged souls of our modern hero's been lime-twig'd with such ignoble conceptions as these , they had never flown up to those rare inventions with which they have so enrich'd our latter dayes ; we had wanted the useful inventions of guns , printing , navigation , paper , and sugar ; we had wanted decimal and symbolical arithmetick , the analytical algebra , the magnetical philosophy , the logarithms , the hydrargyral experiments , the glorious inventions of dioptrick glasses , wind-guns , and the noble boyle's pneumatick engine . nay , what strangers had we been at home , and within the circle of our own selves ? we had yet never known the mesenterical and thoracical lacteae , the blood 's circulation , the lymphiducts , and other admirable curiosities in this fabrick of our selves . all which incomparable inventions do not only solicite , but , me-thinks , should inflame our endevours to attempt even impossibilities , and to make the world know there are not difficulties enough , in philosophy , for a vigorous and active reason : 't is a noble resolution to begin there where all the world has ended ; and an heroick attempt to salve those difficulties ( which former philosophers accounted impossibilities ) though but in an ingenious hypothesis : and , certainly , there is no truth so abstruse , nor so far elevated out of our reach , but man's wit may raise engines to scale and conquer it : though democritus his pit be never so deep , yet by a long sorites of observations , and chain of deductions , we may at last fathom it , and catch hold of truth that hath so long sitt forlorn at bottom thereof . but these are reaches that are beyond all those of the stagyrite's retinue , the solutions of all those former difficulties are reserved for you ( most noble souls , the true lovers of free , and experimental philosophy ) to gratifie posterity withall . you are the enlarged and elastical souls of the world , who , removing all former rubbish , and prejudicial resistances , do make way for the springy intellect to flye out into its desired expansion . when i seriously contemplate the freedom of your spirits , the excellency of your principles , the vast reach of your designs , to unriddle all nature ; me-thinks , you have done more than men already , and may be well placed in a rank specifically different from the rest of groveling humanity . and this is the age wherein all mens souls are in a kind of fermentation , and the spirit of wisdom and learning begins to mount and free it self from those drossie and terrene impediments wherewith it hath been so long clogg'd , and from the insipid phlegm and caput mortuum of useless notions , in which it has endured so violent and long a fixation . this is the age wherein ( me-thinks ) philosophy comes in with a spring-tide ; and the peripateticks may as well hope to stop the current of the tide , or ( with xerxes ) to fetter the ocean , as hinder the overflowing of free philosophy : me-thinks , i see how all the old rubbish must be thrown away , and the rotten buildings be overthrown , and carried away with so powerful an inundation . these are the days that must lay a new foundation of a more magnificent philosophy , never to be overthrown : that will empirically and sensibly canvass the phaenomena of nature , deducing the causes of things from such originals in nature , as we observe are producible by art , and the infallible demonstration of mechanicks : and certainly , this is the way , and no other , to build a true and permanent philosophy : for art , being the imitation of nature ( or , nature at second-hand ) it is but a sensible expression of effects , dependent on the same ( though more remote causes ; ) and therefore the works of the one , must prove the most reasonable discoveries of the other . and to speak yet more close to the point , i think it is no rhetorication to say , that all things are artificial ; for nature it self is nothing else but the art of god. then , certainly , to find the various turnings , and mysterious process of this divine art , in the management of this great machine of the world , must needs be the proper office of onely the experimental and mechanical philosopher . for the old dogmatists and notional speculators , that onely gaz'd at the visible effects and last resultances of things , understood no more of nature , than a rude countrey-fellow does of the internal fabrick of a watch , that onely sees the index and horary circle , and perchance hears the clock and alarum strike in it : but he that will give a satisfactory account of those phaenomena , must be an artificer indeed , and one well skill'd in the wheel-work and internal contrivance of such anatomical engines . finis . errata . in the preface , read daring , instead of darling art. p. . l. . opilionem . p. . l. . bulbe . p. . l. . strange atoms . p. . l. . observat. . p. . l. . adde sound . l. . adde found it had lost . p. . l. . rings . p. . l. . moon wort . and l. . of all things . p. . l. . chive , all . p. . l. . like . p. . l. . lucid . & l. . down . p. . l. . dele ( does . ) & l. . doth direct . p. . l. . and so . p. . l. . and indeed and reality . p. . l. . of that . p. . l. . sun's spots . & l. . sun's image . p. . l. . dele ( but. ) p. . l. . off . & l. cathetus . p. . l. . etch'd . l. . torricellius . p . l. . their ayr. p. . l. . this is . ibid. observ. . experiment . p. . l. . elater . l. . particles . p. . l. . experiments will to satiety . l. . dele ( which ) p. . l . is by far the greatest part thereof . p. . l. . superponderant water . p. . l. . all one . l. . at a free . p. . l. . such a like tube . p. . l. . too . l. ult . dele ( and ) p. . l. . the orifice . p. . l. . intumescency . l. . imprison . p. . l. . about . l. penult . marinus ghetaldi . p. . l. . being open'd . p. . l. . with mountain ayr. p. . l. ult . experimental eviction . p. . l. . in the. p. . l. . conceive . l. . of his philosophy . p. . l. . dele ( of the fire ) and read , therefore . p. . l. . if it . notes, typically marginal, from the original text notes for div a -e d r. brown , relig. med. boyle his essays , pag. . notes for div a -e muffet , de insectis , lib. cap. . muffet , lib. de insectis , cap. . * dr. brown in his vulgar errors . in epistolâ dedicatoriâ , muffeti de insectis . muffet , cap. . de insect . lib. . in epistolâ prefatoriâ , ad muffet . de insectis . muffet , de insect . cap. . pag. . sir francis bacon nat. history exp. . the discourse made before the royal society the . of november, , concerning the use of duplicate proportion in sundry important particulars together with a new hypothesis of springing or elastique motions / by sir william petty, kt. ... petty, william, sir, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) the discourse made before the royal society the . of november, , concerning the use of duplicate proportion in sundry important particulars together with a new hypothesis of springing or elastique motions / by sir william petty, kt. ... petty, william, sir, - . [ ], p. printed for john martyn ..., london : . "an appendix of elasticity" (p. - ) deals with theory of atomic structure. errata: p. [ ]. reproduction of original in yale university library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . atomic structure -- early works to . - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - mona logarbo sampled and proofread - mona logarbo text and markup reviewed and edited - pfs batch review (qc) and xml conversion thursday decem. . . at a meeting of the council of the royal society . whereas it was desired by the royal society , that a discourse made before them by sir william petty knight , at their meeting the . of november last , might be printed : it is this day ordered by the council of the said society , that the said discourse be printed by the printer of the royal society . brounckek , p. r. s. the discourse made before the royal society the . of november . concerning the use of duplicate proportion in sundry important particulars : together with a new hypothesis of springing or elastique motions . by sir william petty , kt. fellow of the said society . pondere , mensurâ , & numero deus omnia fecit : mensuram & pondus numeres , numero omnia fecit . london : printed for iohn martyn , printer to the royal society , at the bell in st. pauls churchyard , . to his grace , william , lord duke of newcastle . may it please your grace , i am commanded by the royal society to print the discourse , which i made before them , upon the last meeting-day of their last year , and next before that of their anniversary election : because , as drapers cut patterns of their whole cloth out of an end , not because the end is better than the rest , but because it may be best spared ; so ( i suppose ) the society are content , that this exercise pass for a sample , pro tanto , of what they are doing ; for that the same may be conceived to consist of three parts , viz. the first being an endeavour to explain the intricate notions , or philosophia prima of place , time , motion , elasticity , &c. in a way which the meanest member of adult mankind is capable of understanding : the second being , to excite the world to the study of a little mathematicks , by shewing the use of duplicate proportions in some of the most weighty of humane affairs , which notion a child of years old may learn in an hour : and the last being , without chymerical speculations , to consider such points and properties , even in atoms ( such , whereof perhaps a million do not make up one visible corpusculum , ) as may give an intelligible account of the nexures , mixtures , and mobilities of all the parts of the universe . in like manner , 't is the profession of the society , to make mysterious things plain ; to explode and disuse all insignificant and puzling words ; to improve and apply little small threds of mathematicks to vast uses ; and yet not to neglect , the finest consideration , even of atoms , where the same is necessary . the which purposes of theirs , i venture to say , do as much differ ( both as to difficulty and dignity ) from what is commonly called wit ( and which takes with far the greater part of mankind , ) as the skill of drawing and painting a cloud or periwig doth from that of designing or painting many complicated figures of men and beasts in some one table , wherein each is perfectly to express some particular passion , and all standing together to contain the true and entire spirit of the story represented : for , in the latter , precise exactness is indispensible , whereas in the former , not onely liberty always , but even extravagancy sometimes is not onely tolerable , but laudable . and when i have said this ; i withal say , that there is one glory of the sun , another of the moon , and another of the stars , which may all consist together , without destroying or maligning each other . and all these several glories shine steddily in your graces firmament . being , i say , appointed to publish this exercise , i have presumed to dedicate it to your grace . first , because the society have been pleased to order it to be published ; ( i dare not say , as approving it , but as committing it to examination . ) secondly , because your grace doth not onely love the search of truth , but did encourage me years ago as to enquiries of this kind . for about that time in paris , mersennus , gassendy , mr. h●●● monsieur des cartes , monsieur roberval , monsieur mydorge , and other famous men , all frequenting , and caressed by , your grace and your memorable brother , sir charles cavendish , did countenance and influence my studies , as well by their conversation as their publick lectures and writings : much of which honours and helps i ow unto your grace , and have a fresh remembrance of them . thirdly , because my lord ogle being now about to carve a significant figure upon my lord his son , by his careful education of him , i thought it a service to his lordship , as well as an expression of my thanks for his former acceptance of my endeavours , to call upon him , not onely to instruct my lord his son in some mathematicsk , but also to store and stock him with variety of matter , data and phaenomena , whereupon to exercise the same ; since lines & numbers , without those , are but like lute-strings without a lute or a hand . for , my lord , there is a political arithmetic , and a geometrical iustice to be yet further cultivated in the world ; the errors and defects whereof , neither wit , rhetoric , nor interest can more than palliate , never cure . for , falsity , disproportion , and inconsistence cannot be rectified by any sermocinations , though made all of figurate and measured periods , pronounced in tune and cadence , through the most advantageous organs ; much less by grandisonous or euphonical nonsence , farded with formality ; no more than vicious wines can be remedied with brandy and honey , or ill cookery with enormous proportions of spice and sugar : nam res nolunt malè administrari . these are the reasons , why i have put your graces name to this treatise ; though there is a contrary reason , why it should have wholly shun'd your graces sight and knowledg : which is , that your grace might not perceive how little progress i have made in thirty years time upon those studies . however i hope your grace will take what i have done for an argument of my patience and perseverance in these pleasant , though profitless , employments , and see , that no heterogeneous cares and troubles have or can quench my affections to philosophy , as no distances of time or place have made me less than formerly , your graces ▪ most humble , most faithful , and most obedient servant , william petty . ult. decemb. . to the right honourable william lord viscount brouncker , president of the royal society . my lord , the observations on the bills of mortality were distinctly dedicated to a peer of this realm , and also to the president of the royal society , and both with good acceptance : wherefore i have also ( like the author of those observations ) dedicated this discourse to his grace the duke of newcastle , for the reasons in the foregoing epistle mentioned ; and i now again dedicate the same to your lordship . first , in gratitude for the several assistances i had from your lordship towards the experiments mentioned in this discourse . secondly , because your lordship is an eminent iudge in those matters , a person whose animadversions i shall take for kindnesses ; and who is able to excuse the errors , and defend the truths i have delivered . lastly , for that near half the whole discourse relates to shipping , artillery , fortresses , sea-banks , &c. which all concern his majesties service , and part whereof are happily entrusted by him to your lordships care ; i thought i might express my affection to those his majesties concernments even by offering this my mite unto them . vpon the whole matter , i have layd hold on this occasion , to publish my desire of being esteemed , my lord , your lordships most humble and faithful servant william petty . ult. decemb. . errata . page . l. . r. proportion . p. . l. . r. be for being . p. . l. . r. &c. be . p. . l. . r. moreover for viz. ibid. l. . r. mice , or rather some smal animals ( whose correspondent parts are but / in length of the horses . ) ibid. l. ult . r. / for / p. . l. . r. numerus for numerous . ib. l. . v. of for or . p. . l. . r. whereof for thereof . a discourse to the royal society . forasmuch as this society has been censured ( though without much cause ) for spending too much time in matters not directly tending to profit and palpable advantages ( as the weighing of air and the like ) i have therefore , to streighten this crooked stick , bent it and my present discourse the quite contrary way , viz. to the sails and shapes of ships ; to carpentry and carriages ; to mills , mill-dams , bulwarks ; to the labour of horses , and to several other particulars : the which are not only gross enough of themselves , but are also as grosly handled in this exercise , to prevent the further imputation of needless nicity , and to leave room for your own further thoughts upon the same . and forasmuch as we have been also complained of for producing nothing new , i have together with my instances and applications , above and hereafter mentioned , presented you as an appendix , to what is said of springs and other elastique bodies , with a new theory ( as i think ) of elasticity it self , and that mechanically explicated in order to make a breach on this hard rock in philosophy , and to chip off a little of that block which has long lain thwart us , in the way of our enquiries . upon the whole matter i have followed the example of elderly divines , who finding their flocks not to mend their lives by perplexed discourses about predestination , transubstantiation , &c. betake themselves at last to preach faith and good wooks , neighbourly love and charity , or doing as we would be done unto , and the like . for i have in this exercise declined all speculations not tending to practice , and ventured at few new hypotheses , but that of elasticity ; rather calling upon you to review your own former observations , and to apply your mathematicks to matter , so as both may be improved to the profitable purposes hereafter mentioned . wherefore the title and scope of this exercise is , several instances , wherein the consideration of duplicate & subduplicate propoortion , or wherein the consideration of sides and their squares is of use in humane affairs . and the instances which i have pitcht upon for this day are these following , viz. . in the drawing or driving powers , which force ships or other bodies through the water , with reference to the respective velocities caused thereby . . in the shapes or sharpness of bodies , cutting or dividing the water , through which they are driven or drawn , and in the different velocities arising from thence , where the bodies and forces are equal . . in the strength of timbers or other homogeneous materials applied to buildings , to carts , or any other machinaments intended for strength : and how by a model to judg the sufficiency of such engine as is represented by it . . in the effect of oars upon equal and like vessels , according to their numbers , length , blades , and motions with or against the stream of smooth or uneven waters . . in the motion or travelling of horses , on their several paces , and with different burthens on them . . in the strength and velocity of mills and their wheels . . in the effects of gunpowder . . in the distance at which sounds may be heard . . in the distances at which odoriferous ▪ matters may be smelt . . in the distance at which the objects of sight may be seen . . in the time of the returns made by vibrating pendules . . in the lives of men and their duration . . in musical & sounding bodies , such as strings and bells . . in the effects and motions of fire , and burning spirits . . in the rising and falling of bodies , but especially of water in pumps , overshot mills , leaks in ships , the heights of rivers at their head above their fall into the sea. . in bellows , . in the prices of several commodities , as masts , diamonds , large timber , amber , loadstones , &c. . in mill-dams , sea-banks , and in the bulwarks or walls of fortresses . . in the compression of wooll , and other elastick bodies , and of the air within diving vessels , as also in the effects of skrew-presses upon several materials . having thus enumerated my several instances , wherein duplicate , and subduplicate proportion is of great importance ; i might now fall down-right upon the application of those proportions to each of the respective matters above mentioned . but because custome hath made it almost necessary to make a preface to every discourse , my preface to this one lecture shall be such , as may serve me for many more ; that is , an explication of what i my self ( at least ) understand by matter , body , figure , place , motion , quantity , quality , habit , time , proportion , weight , swiftness , force , and elasticity ; which i shall do without imposing or scarce recommending the same to any other . for i would be glad , when any man speaks to me in matters of importance , by words which he uses often , that he would first give me a dictionary of such words , to contein what he himself meaneth by each of them . wherefore i shall , as a preface , prefix this dictionary , wherein i dare not define matter by ens , or substance , because i think most men conceive matter better than they do either of these two words , ens , or substance . nor do i define the words , think , consider , or conceive , by the words , soul , spirit , act , or the like , for the same reason . but presuming you all understand , conceive , imagine , or fancy the words matter and thought , as well as any other i can use , i venture to say as followeth , and first , that . place is the image or fancy of matter , or matter considered . . quantity , the fancy of place . . ratio , several quantities considered together . . proportion , several like rationes . . situation , several places considered together . . figure is quantity and situation considered together . . body is matter and figure considered together . . motion is change of place . . time , the image of motion . . quality , several motions considered together . . habit , the same motions repeated . . likeness , several figures , or qualities , and proportions considered together . . swiftness , time and place or space considered together . . force is body and swiftness considered together . . right is the image of possession , and is to it as place to body . . elasticity i shall speak of hereafter . in the next place , i suppose all the first matter of the world to be atoms ; that is , matter immutable in magnitude and figure . i suppose corpuscles to be as many atoms joyned together , as make up a visible or sensible object , and that all iuncture of atomes is made by their innate motions . moreover i suppose , that every atom is like the earths globe or magnet , wherein are three points considerable , viz. two in the surface , called poles , and one within the substance , called center , or rather byas , because in atoms we consider neither magnitude nor gravity . these atoms also may have each of them such motions as copernicus attributes to the earth , or more . lastly , motion to or from a point makes a streight line , and , about it , a circle . but from the center to several points in the circle , is angle . we further say , that the motions of corpuscles are compounded of the abovementioned motions of atoms ; and the motions of bigger and tangible bodies ( viz. their qualities ) are decompounded out of the motions , situation , figure , and magnitude of corpuscles ; and that out of , and by , the premisses all phaenomena in nature must be solved . and this is all the preface i shall trouble you with , being ( as was said ) the dictionary wherein to find what i mean by every material word i intend to use in this ensuing exercise , which we thus begin , viz. the first instance , wherein duplicate , and subduplicate ratio or proportion is considerable , is in the velocities of two equal and like ships ; which velocities , i say , are the square roots of the powers which either drive or draw them ; as , for example , such two ships having sails near double to each other , or as to , the velocity will be as , the square root of unto , the like root of . again , if the sails be near triple , or as to , there the velocity shall be as ( the root of ) to ( the root of . ) so as a quadruple sail is requisite to double swiftness , and noncuple to treble ; that is , the sails must be in duplicate proportion to the swiftness of the ship ; or this , in subduplicate to that . again , let there be two ships of equal sails , but of unlike or unequal sharpness , suppose the head of one extremely obtuse or quite flat , and the head of the other to be an isosceles triangle added thereunto ; i say , the swiftness of these bodies shall be as the roots of the perpendicular of that triangle to the root of half the base , or half breadth of the same . secondly , or if the same triangular head be cyphered away into an angle from bottom to top ; then , as the root of the same perpendicular is to the root of the depth or thickness , so are the velocities . thirdly , if the said head be cyphered both wayes together , then the proportion of velocities shall be as half of one of the above mentioned proportions added to the other whole proportion : ex. gr . suppose the perpendicular of the triangle-head be , the half breadth , and the whole depth be ; then the one proportion shall be as , the root of , to , the root of : the half of which proportion is as to ; and the other proportion is as , the root of , to , the root of . now add the proportions of to , to that of to , the sum will be , as to , or as to . fifthly , suppose two paralellepipedons of unequal heads or resistances , ex. gr . as to , or to : and suppose the sail on the bigger , to that on the lesser , to be as to , or to ; then the velocity of the bigger shall be to the velocity of the lesser , as the root of is to the root of . for if the resistances be as to ; then , if the sail of the bigger to that of the less were proportionable to the resistances , the sail of the less should be , whereas we suppose it but . wherefore the velocity shall be as the root of , which is almost , to the root of , which is about ½ , that is , as about to . memorandum , that wetting of sails ( by lessening the intersperst apertures between the threds of the sail-cloth ) doth make the sail , as it were , bigger ; which biggerness may be known and measured by the increase of the ships velocity upon such wetting . for , if the ship should move one tenth part quicker after wetting than before , we may conclude the sails are swollen to the equivalent of about ⅕ part bigger ; for ( whose root is ) exceeds , whose root is , by about ⅕ of . by these ways the different velocities , arising from the different trim of the same ship , may be also computed , the best trim being that which makes least resistance , caeteris paribus . now , having said thus much of the effects of sharpness and sails , ( the two principal causes of velocity in shipping , and unto which all others may be referred ; ) i shall add , that the want of these two advantages are the chief cause , why short , bluff , undermasted vessels sail cheaper than others . for suppose two ships ▪ of equal burthens , but of unlike dimensions , the main beam of the one being scarse ⅓ of the keels length , and in the other , a full ⅕ th ; i say first , that the hull of the latter shall cost ⅓ part more than that of the former , and the advantage as to sailing shall be scarce ⅙ part . again , suppose , the sharper could carry ½ as much sail more as the bluffer , whereof the advantage in sailing would be ⅙ part more , in all ⅓ . now , where the sails are as to , the masts and yards must be as to in substance ; and in value much more : and where the masts and yards are as to in weight and bulk , the cordage and rigging must be answerable : and where the masts , yards , sails , and rigging are great , the wind-taught of the ship will correspond , and will require proportionable cables ; and the weight of the anchor must follow the size of the cable , and the number of hands must be proportionable to all the premisses : so as the one ship will cost at least double as much as the other , and will sail at double charge of wages and victuals , ware and tare , &c. now if no trading ship be ( one time with another ) above / of her whole reign under sail , or days in , suppose the sharper and larger-sail'd ship sail in dayes what the other performs in ; the difference will be but dayes in , or / part of the wages , and victuals , and other charges ; whereas the charges is supposed to be more than double . i say , this consideration is of great weight in vessels of burden , especially such as carry gross and cheap bulky commodities , neither liable to damage or perishing : of which goods parts of of all seacarriage do consist . but on the other hand , where safety against enemies , speedy dispatch upon important occasions , or preoccupation of a market are in the case , there sharpness and great sails may be admitted to the greatest proportions practicable . having thus digressed , i mind you that we said , velocities are the roots of resistances and extent of sails , &c. it may be well askt , how we know the same , since that very few seamen or shipwrights , either in their writing or discourses seem to understand or own this important position . to which i answer , that i have by many observations , calculations , and comparisons , found the same to be praeter propter true , although there be many circumstances which intermingle themselves in this experiment , so as to disturb and confound it : as namely , the ill placing of masts , the ill cutting and standing of sails , the ill trim of the vessel , with the cleanness or foulness of the same ; the sails more or less worn or wet ; as also taught or slack rigging , &c. wherefore not onely to avoid these last mentioned intricacies , but also to make these positions examinable by every one that desires it ; i say , that the different velocity of bodies ( of several sharpnesses , and as drawn or driven by different powers of knocks or falling weights , ) have been by my self and others much experimented in large canales , or troughs of water , fitted with a convenient apparatus for that purpose , and by no man more , nor more judiciously , than by the right honorable the lord brouncker , president of this society . for i do not think it hard to conceive , that weights and sails are powers of like effect , and reducible to the same principle ; so as if a body have moved in double velocity , when drawn by a quadruple weight ; and in triple , when by a noncuple weight ; i doubt not but the same will hold in sails , or other impellent powers of the same proportions . and for the further clearing or easier trying hereof , i offer two small machinaments heretofore made in this society : the one , to measure the velocity of the wind , and the other its power or equivalency to weight ; whereby it did and will appear , when the wind is of double velocity , it will stir a quadruple weight ; and the like in other cases according to the proportions of roots and squares above mentioned . the same may also be seen even in any good turnspit-jack , where a quadruple weight makes double velocity ( at the same distances of time from the beginning of the motion ) both in the time of the weights descent , as also in the revolutions of the fly , and each intermediate wheel . now perhaps the reason of these phaenomena may be here expected ; to which i answer , that the many parallel instances above and hereafter mentioned , do , like concurrent witnesses , prove the premisses , at least as to any practical use . and as for giving other reasons ( which i take to be explaining this subject from the very first principles of atomical matter , and motion ) i leave it to discourse , as too long for this exercise . the second instance is in the strength of timber , &c. let there be square rods or pieces made of any clean timber , or other materials , whose ends let be supported with convenient blocks or fulcra : these rods in experience will bear weight hung in the middle of them , according to the proportion of their lengths or distance , between the fulcra ; that is to say , a rod a. being of double length to the rod b. will bear ½ the weight which b can bear ; and being of triple length , it will bear one third ; & sic de caeteris . again , let two of those equal and alike square rods be placed one upon the other ( so as to touch and sit , ) then the two together shall bear times as much as one alone , and three of them , placed as afore-said , shall bear nine times as much , and so on in proportion of roots to squares . again , lay the same two rods side by side , to each other , then they shall bear but double , three shall bear triple , and so forward , in arithmetical proportion . from whence it follows , that four of them placed square , shall bear eight times as much as one alone . but if the same four rods taken as one , being of double length making an octuple quantity to one , they shall bear but four times the weight of one alone . so as two like pieces of timber , that are in cubical or triplicate proportion of their sides , are strong but according to duplicate proportion , or the squares of their respective sides ; and consequently , to have like vessels ( differing in content as the cubes of their like sides ) equally strong , the timber of which they consist must be quadrato-quadratic ; that is to say , a ship of tuns , equally strong with one of , must have not only times as much timber in it , but times ; which is seldom or never done . which defect is the true reason , why great shipping is both dearer and weaker than small shipping , ( no ship in the world being so strong as a nutshel ; ) i say , weaker , for what is here said ; and dearer , for what shall be said hereafter in the sixteenth instance of masts , diamonds , &c. and on the other hand , if the timbers were quadratoquadratic , then the ship of tuns would be loaden with her own materials ; if the ship of tuns were not over-timbered . now , for not well understanding these matters , many men designing engines of strength , do make models of such machinaments by a scale ( suppose wherein an inch represents a foot , ) by which the model is the / part of the engine intended : and thereupon they conceive , that if the model be strong enough to bear / part of what the great machinament is intended to bear , that then the said great machinament will be strong enough . whereas indeed the model must bear the full / of what is intended for the great machinament ; otherwise great mischiefs will appear in the work. wherefore the square of the linear difference between the model and engin , is the measure and way of trying the strength and sufficiency sought for : the ignorance whereof hath made many a poor projector . upon these principles , a cask which will hold a tun , ought to have times as much timber in it , as the cask which holds onely a barrel , or ⅛ of a tun ; provided one be as strong as the other ( which is not usually seen . ) for the bigger vessels , carts , &c. they are usually the weaker compar'd with the strength of the lesser ; which appears also in animals , whose strength is as the square roots of their weights and substance , viz. if . mice were equiponderate to one horse , the said horse is but / part as strong as all the said mice . from these considerations the scantlings of timber in buildings must be adjusted ; as for example , let the walls of any room be infinitely , that is , sufficiently strong ; let the length and the breadth of the room be given : next , suppose the room is to be made so strong , as that every foot and a half square shall bear a man , and so , that ½ square feet should bear a tun weight , ( reckoning men to the tun : ) lastly , let the strength of the timber be also given . now the questions are , to find the scantlings of the girders , gise , &c. first in square pieces , and afterwards by altering the squares into more advantageous ablong sizes ; as for example , let the room be supposed foot long and broad , viz. foot in the area , and able to receive about men , and to bear about tuns . suppose the timber be such , as whereof a rod of an inch square , and foot long , will bear / part of an hundred weight ; or , that such rods , or a board of inches broad , and foot long within the walls , an whole hundred weight ; and so the whole floor consisting of about such boards , but . now if the same board were planck of inches thick , it would bear times or hundred weight : if inches , hundred weight : but the whole weight designed being but hundred , some size between and inches thick will suffice in this case , where we suppose the floor to be of planck without gise or girder . next , suppose instead of this planck there be used gise of double thickness to the said planck , and placed at quadruple distance ; i say , the effect and strength will be the same with half the stuff . and i also say , that one girder alone of inches square , and foot long , is near equivalent to the gises of inches deep , and ½ broad-abovementioned ; which girder has but half the stuff which the gise had ; as the gise did contein but half the stuff , which the ½ inch-planck first mentioned did contein . which saving of stuff is the reason of dividing plank into girders , gise , and board . where note , that these proportions and scantlings are not offered as exact and best for practice , but onely to intimate the method of inquiring into these matters so useful in the world . the third instance ▪ in the oars of a boat , &c. to determine or make a good estimate of the power of oars , i first , for easier calculation , suppose a paralellipipedon-boat or vessel , of breadth fit for a pair of skulls , viz. of about foot broad , and of length sufficient for such skulls or oars , viz. about foot long , and one foot deep , and to draw but three inches water . next , i suppose , that every skuller with his skulls and bench , &c. their weight to be equivalent to three cubical foot of water ; so as every pair of skulls ( with its appurtenances ) depresses or sinks the vessel / of a foot , or about ¼ of an inch . now , suppose also a smooth calm standing water , in which one rower will row this vessel foot , or above two miles in an hour or seconds ; i say then , that , if one remex or skuller move quarters or inch . es draught , feet forward in seconds ; then like rowers shall move the same vessel , drawing quarters , or ¾ inches of water , the same feet , in seconds plus seconds , or in all , seconds : and that shall row the same vessel , as the root of to the root of , which is , as near to ; or in / of the time that one rower alone could have done the same . again , suppose each oar lengthened from two to three , and that as many stroaks are made in the same time as before ; then the velocity shall increase proportionably . but suppose , that the oars remain of the same length , but that the blade be doubled ; then the velocity shall increase but according to the roots of that doubling , or as to , or to , &c. supposing still the same number of stroaks , within the same time , in every case or experiment . again , suppose these experiments be made not in still water , but in water which runs foot an hour ; then , against the stream the velocity will be lessened by one half , and accelerated answerably with it . lastly , if the said water be so rough , as that the vessel heavs and sets , suppose degrees of the quadrant in it ; then , for asmuch as the boats way will be encreased as much as the tangent of degrees exceeds the radius , the way or velocity of the boat must abate proportionably . the fourth instance . in the motion of horses . suppose an horse can travel miles an hour with pound burthen on his back ; then with half the said burthen he shall travel ; and with double but three miles and a half . again , suppose a horse with pound burthen can endure to travel hours per diem ; then with half the same burthen he may endure hours , and with double but hours . lastly , suppose a horse ( as race-horses ) can run after the rate of four miles in ⅛ of an hour , or miles per hour , then they can run about miles / in ¼ , or after the rate of / miles per hour ; and in one half an hour can run miles , or after the rate of miles per hour ; and in a whole hour can run / miles ; and in hours can run miles , or miles per hour ; and in hours can run miles , at miles per hour ; and in hours , or miles per hour ; and in hours may go miles , or miles in an hour . all which agrees well enough with experience . the fifth instance , in mills . where the wind blows , suppose , on a saw-mill , in double velocity , there the saw-mill , which carried but one saw , shall carry four ; if treble , shall carry nine . and the like is true of water gushing out upon the floats of under-shot mills ; as may be seen in the stampers of paper-mills , the stocks of fulling-mills ; and other works of the like nature . the sixth instance , in gunpowder . the way of a bullet , shot out of a good gun , is as the square roots of the quantity of the gunpowder fired ; i say , of powder fired , because what goes out unburnt , goes rather as shot than powder ; and the length of guns signifies only the constraining of the powder within the lines of direction , till it be all fired : the use of hard ramming and screwing of guns , being also the same ; and the excellency of powder being to fire quick , and before it goes out of the gun. i say therefore , the velocities caused by gun-powder are as the roots of the powder fired , that is to say , pound of powder , all equally fired within the piece , shall carry a bullet twice as far as one pound shall do ; and in time , as to ; which last mentioned numbers are the roots of the double distances afore-mentioned . now , if the capacity of the concave of guns ought to be , as the weight of their bullets or powder ; then , if the just length of any one gun hath been well found by good experimentation , then may also be known the length of every gun for every bullet respectively . as , for example , suppose a gun , that carries a ball of inches diameter , be foot long in the concave , then the content of the said concave will be cylindrical inches . now the question is , how long must the piece be , which carries a bullet of inches diameter ? i say , that forasmuch as the weight of the inch bullet , to that of , is as to ; the concave of the greater gun must be in the same proportion to , viz. like inches , so as it may contein and fire a proportionable quantity of powder : which being divided by the area of the bullet , , the quotient will be inches , or foot ; that is ( to speak shortly and plainly ) the length of guns must be measured by the diameters of their respective bullets . i cannot say , i have tried the effects of gunpowder to be in the abovemention'd proportion , but have credibly heard it to be so ; and because of the similitude of sails , weights , knocks , and the other points above described , unto this of gunpowder , i believe it ; and recommend it to your further thoughts and experience . the seventh instance . of sounds . let there be many equal sounds ; i say , that the distances , at which they may be heard , are the roots of the numbers of such sounds . for , four musquets will be heard twice as far as one , and nine thrice ; and so of the rest . by which reckoning , the hearing of some of our fleets engagement with the dutch even to s. iames's park near this city is easily solved ; and the truth of that observation doth reciprocally countenance this doctrine . for suppose both fleets ( consisting of two hundred ships great and small ) had about pieces of ordnance on board them , which at a medium suppose to be demi-culverins : suppose also , that a demiculverin , with the same circumstances of wind and air , may be as easily heard five miles , as the said engagements were heard miles . then i say , that of the said guns firing together , or very near the same time , might ( as they were ) be well heard miles ; and that about such guns might as well be heard - miles , as one demi-culverin five miles ; which last point i add , to prevent the unbelief of a probable matter , when it shall happen . now what effect this had in the popes presage of the battel of lepanto , i know not . the eighth instance of smells i say the same of smells , viz. that the distances at which they are perceived are the roots of the quantity of the matter out of which they are emitted ; which doctrin i apply to solve what i once did hardly believe , viz. that ships coming from america towards portugal , did smell the rosemary and other odoriferous herbs miles off from the land : the which seems not only credible , but very likely . for , if a foot square of a rosemary-field may be smelt one perch or rod ( whereof make a mile , ) then about acres of land , whereon such sented plants do grow ( or a piece of land about miles long , and miles broad ; or miles long , and miles broad ) may be smelt miles : and acres of the like land , or a parcel of such land about miles square , may be smelt as many leagues , or near miles . and this consideration i pitch upon , as one of the grounds whereupon i would build a doctrin concerning the influence of the stars , and other celestial or remote bodies upon the globe of the earth , and its inhabitants , both men and brutes . the ninth instance concerns visible objects . i say also , that four equal and like candles will give light but twice as far as one , and , thrice as far ; and that will also enlighten but times as far as one , &c. and if a flag or ships-vane of a yard square may be seen a league off at sea , it must be yards square , or square yards to be seen leagues , and so forward . but whoever will make experiment hereof , must first consider , how many miles in thickness of a middling , clear , and diaphanous air do make an opaque . for we find , that although a very thin plate of clear glass seems to hinder our sight of near objects but very little ; yet we also know , that great number of them ( suppose one hundred ) can scarce be seen through at all . hereunto also must be added the consideration of the convexity of the earth ; and then i doubt not , but this doctrin ( of roots and squares ) rectified and corrected with the two additional considerations last mentioned , will hold concerning visible and lucid bodies , as was above propounded . the tenth instance , in the time of the vibration of pendules . the times in which the returns of a vibrating pendulum are made , are the roots of the distances between the center of the pendulum , and the center upon which it moves . i shall need to make no application of this truth , since we all enjoy the benefit of it in our more regulated clocks and measures of time , which are now in common use , and from whose improvements we may most hopefully expect a better measure of longitude upon the surface of the earth . the further uses which may be made hereof , ( it being a very simple and examinable experiment ) is to witness and give evidence to other the more abstruse and complicate positions , which are of the like and parallel nature . the eleventh instance in the life of man , and its duration . it is found by experience , that there are more persons living of between and years old , than of any other age or decade of years in the whole life of man ( which david and experience say to be between and years : ) the reasons whereof are not abstruse , viz. because those of have passed the danger of teeth , convulsions , worms , rickets , measles , and small-pox for the most part : and for that those of . are scarce come to the gout , stone , dropsie , palsies , lethargies , apoplexies , and other infirmities of old age. now whether these be sufficient reasons , is not the present enquiry ; but taking the afore-mentioned assertion to be true ; i say , that the roots of every number of mens ages under ( whose root is ) compared with the said number , doth shew the proportion of the likelyhood of such mens reaching years of age. as for example ; 't is times more likely , that one of years old should live to , then a new-born babe . 't is three times more likely , that one of years old should attain the said age of , than the said infant . moreover , 't is twice as likely , that one of should reach that age , as that one of years old should do it ; and one third more likely , than for one of nine . on the other hand , 't is to , that one of years old will die before one of ; and to , that one of will die before one of ; and to , that the same person of shall die before him of : and so forward according to the roots of any other year of the declining age compared with a number between and , which is the root of , the most hopeful year for longaevity , as the mean between and ; and is the year of perfection , according to the sense of our law , and the age for whose life a lease is most valuable . to prove all which , i can produce the accompts of every man , woman , and child , within a certain parish of above souls ; all which particular ages being cast up , and added together , and the sum divided by the whole number of souls , made the quotient between and ; which i call ( if it be constant or uniform ) the age of that parish , or numerous index or longaevity there . many of which indexes for several times and places , would make an useful scale of salubrity for those places ; and a better judg of ayres than the conjectural notions we commonly read and talk of . and such a scale the king might as easily make for all his dominions , as i did this for this one parish . the twelfth instance in musick . take a musical string , one end thereof being fastned ; hang unto the other ( over a convenient bridg ) any weight which may strain it to some grave musical tone or note ; then set some other string of near the same length , unisone thereunto . lastly , instead of the first weight , hang to the first string the quadruple of the same weight ; and it will appear , that the string with the quadruple weight shall yield a tone of an th or diapason above it self , when singly charged . the reason is , because the quadruple weight doubles the number of vibrations , ( being the root of : ) and for that the ratio formalis of tones lieth in the number of the vibrations ; and of the diapasons , in the doublness of such numbers . by the same method of hanging-on several weights at one end of the same string , all tones may be produced , of which such string is capable . the tones or notes also of like bells and drums do follow the same proportions of their tension and mettal , so as able artists can cast bells in tones assigned . the thirteenth instance , of fire and spirits . let a cylindrical flat-bottom vessel be filled with water , and let it be tried , in what time one lamp or candle would make the water boyl through , or come up to its greatest heat : then see , in how much lesser time , , , or more like fires will hasten the same effect . i cannot speak positively hereof , but know from several observations , that the acceleration abovesaid shall not be made in arithmetical proportion ; forasmuch as i know , that in fire-works great fires are more profitable than small ; as in brewers coppers , and iron-works may be seen ; wherein double fires produce more than double dispatch or advantage . i shall therefore suspend this matter , and pass to the measuring of the spirituosity of liquors , or in what proportions several liquors contein more or less of inflameable or ardent parts . now in this case i conceive , the consideration of roots and squares is also material ; for i understand by strength or multitude of spirits , the space , greater or lesser , into which such liquors will be rarified , or will fill with spirits : as for example , if a pint of water rarified into vapour will fill a globe but of foot diameter ; and a pint of rectified spirit of wine will fill a globe of six foot diameter , or times as large as that of water ; i shall say , that there is times as much spirit or vapour in one as in the other . but if these liquors were put into open lamps or vessels , there the space in which the spirits rise , are the roots , whose squares do shew the spirituosity of those liquors : ex. gr . let there be a lamplike vessel of common aquavitae ; in which place a week as high as the same will burn by the rising of the spirit unto it , suppose an inch above the surface of the liquor : now , let there be a like equal vessel with such a spirit , as will rise up higher , suppose to a week placed two inches above the surface ; in this case , i say , that the latter liquor is quadruple in strength or extent of spirit to the former ; for 't is certain , that as the spirit riseth double upwards , so also it emitteth or rarifieth it self double also sideways ; and consequently the quantity of the spirit or vapour must be quadruple ; and so of other proportions . the fourteenth instance , of rising and falling bodies ; but particularly of waters in pumps and river-streams . let it be observed in the transparent pipe of a forcing pump , at how many stroaks the water is forced from the bottom to the top ; and let as many marks be made at the several places unto which the water mounted at every stroak ( which stroaks we suppose to be all in equal times ; ) it will appear , that all the said divisions will be according to the proportions or the logarithms above-mentioned . as for the descents and accelerations of falling bodies , the times are the roots of these spaces , which they fall in the said times respectively . the great effect whereof we see in overshot-mills , where a little water falling upon a wheel of a large diameter , produceth wonderful effects ; the which may be well computed upon the principles we hold forth . waters also have greater forces in the above-mentioned proportions , as the hole or place whereat they issue is lower from their surface ; as may be seen in all breast ▪ and undershot-mills ; where it is pleasant to divide the sinking of the water into equal spaces , and to count the clacks , revolutions or stroaks made within the time of the waters sinking every such equal space ; for therein the above-mentioned logarithmes may also be observed . unto this head may be referred the leakage of ships . for let there be a hole in a ship somewhere under water ; then let it be seen , what water comes in at the said hole , within any space of time ; then let the like hole be made at double the perpendicular distance from the top of the water , and there shall come in four times as much as at the upper hole ; and let a third be at three distances , and that shall admit times as much , &c. again , let there be two equal holes or leaks in a ship , the one at head , and the other at stern , and let the ship be in motion ; then the leakage at the head is composed of the pressure of the water from the surface , and of the ships motion together . moreover , if the ship make double way , the leakage will be quadruple ; if treble way , non cuple , &c. wherefore to stop leaks afore , the ship must stop its motion , lye by , or bear up to go with the wind and sea , &c. lastly , i shall add , that the swiftnesses of waters or river-streams , are the roots of the power that causes them ; which causes are steepness or descent in a sharper angle from the perpendicular . wherefore knowing by observations , what degree of steepness causeth any degree of swiftness ; hereby , and by our doctrin , the height of ground where any river riseth above its fall into the sea , may be computed . the fifteenth instance , in the blast of bellows . in iron-work furnaces are the greatest and most regular moving bellows that are any where used ; the which are commonly turned by the evenest overshot wheels . now the times wherein these bellows rise and fall , are roots of the strength of such bellows-blast upon the fire ; for rising in double quickness admits double air in the same time ; which being in like manner squeezed out again , double quickness makes double expulsion , and consequently double swiftness ; ( the whole passing through the same twire-pipe in half the time ; ) and double swiftness makes quadruple effects upon the fire or furnace , as aforesaid . the sixteenth instance , in the price of several commodities . suppose a mast for a small ship be of inches diameter , and as is usual , of foot in heighth , and be worth s ; then a mast of inches through , and double length also , shall not onely cost eight times as much , according to the octuple quantity of timber it conteins , but shall cost times as much , or l. and by the same rule , a mast of inches through shall cost times l. or l. of which last case there have been some instances . but whereas it may be objected , that there are no masts of four times , or foot long , i still say , that the rule holds in common practice and dealing . for , if a mast of inches thick , and foot long , be worth s ; a mast of inches throughout , and foot long , shall be worth l. and a mast of inches thorough , and foot long ( not foot ) shall be worth near l. moreover , suppose diamonds or pearls be equal and like in their figures , waters , colours , and evenness , and differ onely in their weights and magnitudes ; i say , the weights are but the roots of their prices , as in the case aforegoing . so a diamond of decuple weight , is of centuple value . the same may be said of lookingglass-plates . i might add , that the loadstone a , if it take up times more than the loadstone b , may be also of centuple value . lastly , a tun of extreme large timber may be worth two tuns of ordinary dimensions ; which is the cause of the dearness of great shipping above small ; for the hull of a vessel of tuns may be worth but l. per tun , whereas the hull of a vessel of tuns may be worth near l. per tun. from whence arises a rule , how by any ships burthen to know her worth by the tun , with the number and size of her ordnance , &c. the seventeenth instance , in mill-dams , sea-bancks , and bulwarks of fortresses . suppose any wall , dam , or banck , to be just sufficient to keep out or resist the sea , or other stream against the appulse of its waters , being of a certain force ; i say , that to make this wall or damm strong enough against a double swiftness of appulse , it must be augmented by quadruple thickness ; and if it must be made sufficient against the greatest violence which ever was observed , then that violence being known , is the root of the number by which the walls thickness must be augmented . so cannon-bullets do execution or batter in duplicatâ ratione of their swiftness ; and therefore ramperts must be strong and thick in duplicatâ ratione of the said swiftness , which depends upon the distance of the battery , and the degrees of tardation , which bullets make in every part of their way between the gun and the rampert , which they are to batter . where note , that bullets commonly beat out a cone of wall , whose vertex is in the bullets entry , and like the conical fovea to be seen in the sand of an hourglass . the eighteenth instance , in the compression of yielding and elastic bodies , as wooll , &c. suppose some cylindrical or other parallell'd sided vessel , fill'd with wool , or down , or feathers , or other elastic materials ; let the same be covered with a moveable head ( such as in pressing of pilchards they call a buckler ; ) then first observe , how low the buckler descendeth by its own weight ; and then upon this head or buckler lay a triple weight , to make the whole quadruple , and it will appear , that the buckler will sink but just as much lower ; and being noncuple , another like space lower : so as the several spaces of depressions are the roots of the depressing powers . from hence may be seen , how the force must be increased at every turn or thred of a screw-press ; which being done according to the proportions here understood , i doubt not , but a light substance with a convenient apparatus , might be compressed unto the density and weight even of gold. but , that silver might be so condens'd , i made no question , till i heard of some anomaly in the practice , which i must better consider of . the further truth whereof doth appear in the vnder-waterair within the vessels of water-divers , who the lower they go , do find their stock of air more and more to shrink ; and that according to the roots of the quantities of the super-incumbent water or weight . in like manner take a bow , and hang any weight to the middle of its string , and observe how low it draweth the said string . now , if you shall quadruple the same weight , it will draw down double the first distance , and noncuple will draw it down treble , &c. so as in a drawn bow , let the arrow be divided into quotcunque partes , each equal part of the tension carrieth the arrow to an equal distance , notwithstanding each equal part of the tension was made by unequal power , and that each equal space or part also of the arrows first flight requires unequal force , viz. least strength at first , and most at last ; and that , in the proportion first mentioned . so in the fuze of a watch , the greatest strength of the spring is made to work upon the shortest vectis ; and the least upon the longest , so as to equalize the whole . the like also happens in the traction of muscles upon two bones with a turning joynt between them ; which bones and muscles make a triangle , whereof the muscle is the base , subtending the angle-joynt . now in the working , the muscle is strongest , when the vectis is smallest , as lying most obliquely ; and vice versâ , when the muscle and moving bone come to make a right angle . an appendix of elasticity . having done with the consideration of duplicate and subduplicate proportion in elastic bodies and materials , i hope it will not be amiss to subjoyn a short appendix of elasticity it self , whereby to draw forth the better thoughts of other men for countenance or correction . wherefore i say as followeth ; viz. first , supposing every body to have a figure or positure of its own , out of which it may be disturbed by external force ; i say , that elasticity is the power of recovering that figure , upon removal of such force . . i think it easiest to consider elastic , springing , or resilient bodies , as laminae , laths , or lines ; so as a streight lath , being by force bent circularly , doth upon the removal of that force , return to be streight again by its elasticity ; and a circular hoop being forced streight , leaps back into its own crookedness by its elasticity . . elastic bodies in their returns do overshoot their own natural positure , and vibrate cis citrà the point they seek , as doth a pendulum , or magneticneedle , till at length they rest ; the one in his perpendicular , and the other in his meridian . . an elastic body is a gross tangible body , which is made of corpuscles , or the smallest bodies that can possibly be seen ; and these corpuscles are made of atoms , or the smallest bodies in nature ( such as whereof a million doth not perhaps make one of the corpuscles last mentioned . ) . i know no reason , why we may not , upon occasion , suppose atoms to be of several figures and magnitudes , provided we suppose them immutable , such as corpuscles are not ; gross tangible bodies being very mutable by the various additions and detritions that befal them . . i suppose in every atome three such points as we all see and know to be in the globe of the earth , and in every magnet , viz. two poles in its superficies , and a central point within its substance , which i call its byas . the heavens also visibly have their poles , and must have a center of gravity or magnitude , or some other central and predominant point . . i suppose every atome may move about his own axis , and about other atoms also , as the moon does about the earth ; venus and mercury about the sun ; and the satellites iovis about iupiter , &c. . i suppose , that the byas of one atome may have a tendency towards the byas of another near it , and that the byasses of many atoms may tend to some common point without them ; as we see in electrical bodies , and in the globular drops of water and quicksilver , and all mucilaginous substances . . i suppose , that all atoms have , like a magnet , two motions , one of gravity , whereby it tendeth towards the center of the earth , and the other of verticity , by which it tendeth towards the earths-poles , and whereby magnets joyn to each other by their opposite poles . . all atoms by their motion of verticity or polarity , would draw themselves , like magnets , into a streight line , by setting all their axes in directum to each other ; did not the motion of their respective byasses towards each other , and towards other points , curb them into a triangle , whereof the two axes of two atoms are two sides , and the distance between the byass of each making the third side : wherefore i call the polar motion above-mentioned , the motion of rectitude ; and the motion of the biasses , the motion of angularity or curvity , or the angular or curve motion . . i suppose , that all these motions may be of different velocities , and that by contra-colluctations they ballance each other , sometime into seeming rest : i say , seeming , because perhaps there is no rest in nature . lastly , i might suppose ( even without a metaphor ) that atoms are also male and female , and the active and susceptive principles of all things ; and that the above-named byasses are the points of coition : for , that male and female extend further than to animals , is plain enough ; the fall of acorns into the ground , being the coition of oaks with the earth . nor is it absurd to think , that the words in genesis , [ male and female created he them ] may begin to take effect , even in the smallest parts of the first matter . for although the words were spoken onely of man ; yet we see they certainly refer to other animals , and to vegetables in manner aforesaid , and consequently not improbably to all other principles of generation . conclusion . to conclude , i hope i may say , that these my principles , are principles indeed ; for there can be no fewer nor easier than matter and motion . my matter is so simple , as i take notice of nothing in each atome , but of three such points as are in the heavens , the earth , in magnets , and in many other bodies . nor do i suppose any motions , but what we see in the greater parts of the universe , and in the parts of the earth and sea. again , all the motions i fancy in my atoms , may be represented in gross tangible bodies , and consequently may be made intelligible and examinable . moreover , i hope none of my suppositions are inconsistent with each other , nor do necessarily infer any absurdity or falsehood . and lastly , i hope they solve all the phaenomena of elasticity , and , as i think , of hardness , fixedness , tenacity , fluidity , heat , moisture , fermentation , and the rest . all which is humbly submitted to the censure of this society ; whose atoms or inseparable members i wish may happily conglomerate , and unite themselves into the most fixed and most noble bodies amongst the sons of men. finis . peripateticall institutions. in the way of that eminent person and excellent philosopher sr. kenelm digby. the theoricall part. also a theologicall appendix of the beginning of the world. / by thomas white gent. institutionum peripateticarum. english white, thomas, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (thomason tracts ; :e [ ]) peripateticall institutions. in the way of that eminent person and excellent philosopher sr. kenelm digby. the theoricall part. also a theologicall appendix of the beginning of the world. / by thomas white gent. institutionum peripateticarum. english white, thomas, - . [ ], p. printed by r.d. and are to be sold by john williams at the sign of the crown in s. paul's church-yard., london, : m.dc.lvi. [ ] a translation of: institutionum peripateticarum. "a theologicall appendix, of the beginning of the world" has separate dated title page; pagination and register are continuous. annotation on thomason copy: "march ". reproduction of the original in the british library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng digby, kenelm, -- sir, - . philosophy -- early works to . physics -- early works to . - tcp assigned for keying and markup - aptara keyed and coded from proquest page images - john latta sampled and proofread - john latta text and markup reviewed and edited - pfs batch review (qc) and xml conversion peripateticall institutions . in the way of that eminent person and excellent philosopher sr. kenelm digby . the theoricall part . also a theologicall appendix of the beginning of the world . by thomas white gent. london , printed by r. d. and are to be sold by john williams at the sign of the crown in s. paul's church-yard . m.dc.lvi . virg. georg. . happy who things causes has attain'd to know , and all fears and inexorable fate has trampled under feet : — the method of studying . whoe're profoundly searches after truth , and would not be misled by stragling paths ; let him turn on himself his inmost eye , and bend into a ring his ranging thoughts ; making his soul see what she seeks abroad in her own native treasures stor'd up lies : what the black cloud of errour hid , will soon shine clearer then the sun it self at noon . boet. de consol . philosoph lib. . metr . . the translatour's addresse . this happy analysis of nature , which the infinite kindness of my beft friend , the authour , has encourag'd and enabled some pains of mine own to render plain english to my self , i dutifully present to my country : where so many clear wits and strong judgements ( the perfect aptitude to such a philosophy ) may , through the want or disuse of latine , be disabled , or , by the extream concisenesse of the stile , and incorrectnesse of the presse , discourag'd from strugling for it in the originall . the subject , nature and her generall course , is universall and practically indifferent to all nations : it seems , therefore , but just her interpreter , philosophy , should speak all languages ; at least to that fair degree of currentnesse , as abstracted reason it self is , every where , intelligible . upon this resentment , the incomparable sir kenelm digby ( whose expression would i could glory so proportionably to have hit , as my master may his mind ) began lately to teach it our idiom ; which it so soon and perfectly attain'd , as clear evidences his to be the truly - naturall philosophy : what ingenuous courage , once throughly engag'd ( and under so sure a champion ) the same advantagious way , in the same noblest field , could resist the temptation to follow such a leader and such successe , upon so necessary a design ? in short , i have dar'd : nor , i hope , altogether unfortunately ; at least , if an authentick touch of illustration , upon most of the knots and obscurities , in the originall both matter and delivery , may excuse the tolerating still some few terms , purely out of the stubbornnesse of their nature , unreduc'd and , perhaps , unreducible . these , reader , are the translatour's apology and addresse : the authour 's , his known name and the work it self . the authour's design . in what darknesse philosophy lies hudled up , and how perplexing chimaera's reduce it to desperation , 't is needlesse to mention : they see 't , whoever see any thing in it . as superfluous , therefore , 't were to apologize , why i would lend it my slender endeavours . why , such as you see , i offer them , take this account . the main fault seem'd to me to lye at their doores , who neither do themselves nor can endure others should expect any certainty from it. of these i have observ'd two sorts : some there are that avouch as much of geometry it self : some , that attribute this , not to the defect of nature , but to the difficulty of the matter , and the intricatenesse of natures folds . and , i was about to provide a preambulatory disputation to the former : when this dilemma came into my head , that , they either admit the evidence of a legitimate syllogism , or not : if they admit it , they cannot contest against geometry ; if they admit it not , i saw not what farther evidence there was in nature able to force them : they were , therefore , desertours of humane nature ; nor otherwise to be dealt with , then as mad-men . turning , then , to the later sort , i saw ther 's no so smart proceeding as the geometricall way ; where , when 't is ask'd whether a thing can be demonstrated ? the affirmer , producing a demonstration , presently destroyes the probleme : so , i thought , i was to proceed by instances , if i meant to perswade any thing . thence sprung this grain of mustard-seed ; which , to what growth it may hereafter rise , 't is not yet evident . why i have stiled them institutions , the shortnesse and concise connection of the work sufficiently discover . i call them peripateticall , because , throughout they subsist upon aristotle's principles ; though the conclusions sometimes dissent . that i declare them written in the way of that eminent person and excellent philosopher sir kenelm digby ; 't is , because , since , in that so justly-to-beenvy'd book , of the immortality of the soul , he has dissected the whole composition of nature , from the first notion of body , to the very joynts and articles of an invisible spirituall soul , and laid it before the eyes of all ; any other way , then that he had traced out , i neither would nor could proceed . whatever , therefore , you meet with , upon that subject , is borrow'd thence : but so , as that i have transferr'd only the naked bones , scarce hanging together by their sinews ; wholly destitute of those nerves and colours with which they are sated there . there look for nature , where you shall misse neither oratour nor philosopher : we only act the part of abridgers or summulists . the other things which are treated through this whole work , ly yet hid in his cabinet , expecting the pains of greater leisure . if i have call'd this the theoricall part ; i would not , thence , have you expect another practicall one : for , i meant only to declare , that i touch't nothing upon the morall . in logick you have a little ; yet , something , unlesse i 'm deceiv'd , more then need : for , few precepts are to be prescrib'd for use , but a great deal of exercise . out of the rest , if i have cut off the intricate and unprofitable petty questions ; methinks i have deserved thanks . do you ask , what fruits i expect ? that you should believe there is , in nature and in things beyond nature , a no-lesse connection of terms & force of consequences , then in mathematicks : for , this the order , and brevity , and the invincible firmnesse , surely , of some consequences will obtain of an unobstinate person . this if i shall have attain'd ; since all science is lastly resolv'd into the unity of definitions ▪ i hope , naturall science will be rescu'd from desperation . i have divided the books into lessons and very frequent breaks : both for the greater clearness & commodity of citation ; as also , because , conceiving the entrance into these institutions would be scarcely open to novices , without the help of some more skilfull , i have call'd a lesson so much as may , at one fitting , be explicated ; a break , that which at one breath , or with one effort of the mind and voice ; to afford , betwixt the breaks , a breathing space from speaking . to the auditours , questioning is permitted , in that kind as may make them understand the things propos'd ; opposition is prohibited , till they have , once or twice , run through the whole work : for , whilst they are yet ignorant of what lies hid in the things to follow ; by forestalling the order , they spoil the discourse , whilst they tamper with objecting . the work is but short ; and , for a little while , the affection of credulity may be fairly exacted in a learner , that he may clearly apprehend the things propos'd : when he shall have understood against what he 's to object , there will be liberty enough of disputing . you see , a walk or garden may serve well enough for this exercise : i have therefore given you a volume which will not load your pocket . i have follow'd that method which the necessity of consequences drew on , not , the rules of logick prescrib'd , though yet it be not averse from this . if you blame the obscurity , remember , acroases are so to be published , that they become not publick : that their penetration may be difficult without a clue , yet not unpassable to a resolute pursuance . the table . first book . containing that part of logick , which is necessary to sciences . lesson i. of propositions , as they are the parts of a syllogism . pag. . ii. of a syllogism and its conclusion . . iii. of the predicaments in common , and the three first in particular . . iv. of the rest of the predicaments . . v. of the five predicables and the signification of words . . vi. of definition , division and disputation . . second book . containing those things which concern the nature of bodies , in common . lesson i. of the composition of bulk or bignesse . pag. . ii. of the nature of quantity and place . . iii. of time and locall motion . . iv. of the four first qualities . . v. of the elements . . vi. of mixtion and the second qualities , or those which most immediately follow mixtion . . vii . of the manner of mixtion , and the passion of mixt things . . viii . of impassibility , destruction , and the accidents of mixt bodies . . ix . of the motion of heavy and light bodies , and the conditions of acting . . x. of the motions of vndulation , projection , reflection and refraction . . xi . of the electricall and magneticall attractions of hot bodies . . xii . of the generation of decomposit ( or , compos'd-of-compounded ) bodies , & plants . . xiii . of the more universall parts of plants . . xiv . of the accidents of plants . . xv. of the generation and augmentation of animals . . xvi . of the motion of the heart , and some consequents of it . . xvii . of the progressive motion of animals . . xviii . of the five senses of animals . . xix . of the objects of the senses . . xx. of knowledge and memory . . xxi . of sleep and dreams . . xxii . of passions , and the expression of them . . xxiii . of the communicating affections to others . . xxiv . of the seeming-rationall actions of animals . . third book . containing those things which concern the world , and its greater parts . lesson i. of the limitation , vnity , and composition of the world. pag. . ii. of the mortality & kinds of those things that are in the world . . iii. of the parts of the planetary world , and specially those of the earth . . iv. of the sea and its accidents . . v. of fountains , rivers and lakes . . vi. of the aire and those things that are done in it near the earth . . vii . of clouds , rain , snow , & hail . . viii . of fiery meteors appearing in the aire . . ix . of truly fiery meteors hanging in the aire . . x. of the generation and nature of winds . . xi . of earth-quakes & their effects . . xii . of the meteors of the other parts of the world and especially of comets . . xiii . of the ebbing and flowing of the sea , and its accidents . . xiv . of the motion of the earth , and the causes of it . . xv. of the oppositions against the motion of the earth : and of its effects . . xvi . of the motion of the aire , with the earth ; and its effects . . xvii . of the causes of the motion of the moon and other stars . . xviii . of the primum mobile , the duration and quiddity of the world. . fourth book . containing that part of metaphysick , which explicates the essentiall notions of bodies . lesson i. of the divisibility of substance into formall parts . pag. . ii. of the formall parts of substance , in particular . . iii. of the unity and distinction o● bodies , in common . . iv. of the essentiall vnity and distinction of the elements , and mixt bodies . . v. of the essence of animals , & of the soul. . vi. of the chief animal and the essentiall distinction of bodies . . vii . of the mutation of the individuality , in the severall kinds of bodies . . viii . of the proper action of the chief animal . . ix . of the soul of the chief animal , or , of the mind . . x. of the proficiency & deficiency of man , and of his essence . . fifth book . containing that part of metaphysick , which treats of substances abstracted from matter , & of the operation of things . lesson i. of the soul's separation from the body . . ●i . of the science of a separated soul , and its vnity with the soul. . iii. of the eminency of a separated souls acts , above those it exercises in the body . . iv. of the felicity and infelicity of separated souls , and their immutability . . v. of the nature of existence , and its unity with the thing . . vi. of the existence , simplicity and eternity of god. . vii . of the perfection , immutability and science of god. . viii . of the divine volition and liberty . . ix . of the divine names ; how they are improperly spoken of god. . x. of the degrees of impropriety in the divine names . . xi . of the existence , nature , and science of intelligences . . xii . of the comparison of intelligences to souls and bodies . . xiii . of the distinction , subordination and number of intelligences . . xiv . of the action of god , intelligences and bodies , severally . . xv. of the cooperation of the agents to the making of substances , a rationall soul , and to all other effects . . xvi . of the government of god , and the locality of incorporeall things . . xvii . of the conservation of creatures , and the durations of things . . xviii . of the manner of action , on the subjects side . . appendix . chap. i. a philosophicall discourse , concerning the creation of heaven and earth . pag. . ii. an explication of genesis , concerning the same . . iii. a philosophicall discourse of the works of the two first daies . . iv. an explication of genesis , concerning the same . . v. a philosophicall discourse of the works of the other four daies . . vi. an explication of genesi , sconcerning the same . . vii . some animadversions about the text of the first chapter of genesis . . viii . a naturall discourse of the creation of man. . ix . an explication of genesis , concerning the creation of man. . x. an explication of the same , concerning the creation of woman . . xi . an explication of genesis , concerning paradise . . xii . the history of adam's fall , out of genesis . xiii . of the punishment of our first parents : out of the same . . xiv . of the evils derived to posterity : out of the same . . xv. of the propagation of mankind : out of the same . . xvi . of the floud : out of the same . . xvii . of the cessation of the deluge : out of the same . . xviii . of the covenant made with noe , after the floud : out of the same . . xix . of the second propagation of mankind into severall countries : out of the same . . errata . pag. . line . . touching . p. . l. . a constant . p. . l. . del . to . p. . l. . del . ; . p. . l. . turned . p. . l. . by the. p. . l. . he is . p. . l. . immutable . p. . l. . immutable . p. . l. . of a. p. . l. last . by them . peripateticall institutions . first book . containing that part of logick vvhich is necessary to sciences . lesson i. of propositions as they are the parts of a syllogisme . . logick is the art of discoursing . discourse is the progresse of the vnderstanding , out of one thought or judgement into another : but in a more speciall acceptation of the word , 't is a motion whereby the understanding , out of a fit and orderly disposure of some judgements already possessed by it , deduces and leads it self into the knowledge of something it was ignorant of . and this discourse , when 't is close and exactly perfect , is , by a greek term , called a syllogism . . a syllogism is compos'd of three propositions : a proposition is a speech whereby something is affirmed or denied concerning another : whence , to its perfection , three parts are necessary ; that which is affirm'd , that of which 't is affirm'd , and that which expresses the affirmation , or the term which connects them together . . these three are called notions , or apprehensions , or things as they are in the understanding , that is , according to what is common to them in themselves and in the understanding : for , as the statue of caesar in something agrees with , in something differs from caesar ; so the understanding actually possessed of any knowledge , has something wherein it resembles and agrees with the object , other things wherein 't is unlike and differs from it . . 't is already said that propositions are , some affirmative , some negative . now , sometimes it falls out , that an affirmation is applied to one thing alone ; sometimes to divers indifferently , as many agree in some one and the same notion : this last is called an vniversall proposition ; as when we say , every man is a living creature . . when the affirmation is applied to one thing alone , that is taken either determinately , as socrates , bucephalus , &c. and then the proposition is called singular : or else indeterminately , as when we say , some man , or horse , &c. and then 't is call'd a particular proposition . . again : since a proposition is either affirmative or negative ; and the same thing cannot ▪ at once , both be & not-be : if , at any time , one proposition affirms what another denies , such cannot be both true together ; and therefore they are called opposites or incompossibles . . when the affirmation and negation falls upon the same thing in all respects , such propositions are called contradictories ; as , socrates , here and now , runs ; socrates , here and now , runs not : but when the proposition is universall on both sides , they are called contraries ; as , all men are wise , none are wise . . farther : as 't is evident , the same thing cannot both be and not-be , at once ; so 't is as clear that every thing is , whilst it is : whence , if at any time a proposition pronounces the same thing concerning the same , 't is called self-evident ; as when we say , the whole is greater then a part of it self , for 't is as much as to say , a part and more is more then a part . . wherefore , if it be once known , that the same notion is identify'd with two others ; it will presently be evident , that those two are identify'd betwixt themselves : for otherwise , that notion which is the same with them would not be the same with it self . . two propositions , therefore , being put , which discover the identification of some one notion with two others ; a third proposition evidently emerges , whereby the identification of those two notions betwixt themselves is declared : and these three compose a syllogism . lesson ii. of a syllogism and its conclusion . . a proposition being a speech which pronounces one thing of another ; and since , betwixt three , there can be but three variations , viz. that one be pronounced of two , or two of one , or one of another , and that again of the third ; there are onely three sorts or figures of syllogisms . . and , a syllogism consisting of such speeches as connect one term to another ; since , this third way , the term which joyns the rest falls into the midst between them , becoming under or subject to one , and above or predicate to the other ; it truly and properly connects them : whence , that figure whose terms are thus order'd , is call'd the first ; and 't is the chief of all others , for all the propositions and their terms or notions have a constant and determinate place and order in the syllogism : . whereas , in the other figures it imports not whether of the two antecedents be preferr'd ; and , in the conclusion , either of the terms may , indifferently , be the subject or predicate , and , if we look more narrowly into it , the other two figures will , indeed , appear but distorsions of the first ; whereby the notion , which , really , is the middle one of the three , is made one of the extremes , because all the three are identify'd . the first figure , therefore , alone is according to nature , and necessary . . and in this first , because the middle notion is once affirm'd or made the predicate , and once the subject , the conclusion cannot be varied , except it be in respect of the universality and particularity , or affirmation and negation ; whence the conclusion becomes either an universall or particular affirmative or negative ; as uses to be cyphred by these words , barbara , celarent , darii , ferio : in which the vowells shew the nature of the proposition ; a standing for an universall affirmative , e , an universall negative , i , a particular affirmative , o , a particular negative . . and , because these four differences contein all manner of propositions , in which truth may be look'd for ; there are onely four moods or forms of syllogisms profitable , and they sufficient to deduce it : the rest are all provided rather for curiosity and abundance then benefit . . there is another kind of syllogism which some call expository , consisting purely of singulars : and because a singular proposition comprehends its notion as well as an universall , 't is a perfect syllogism , though little used in sciences , and therefore little treated of . . again ; since those things which are circumstantiall to any other thing either belong to it , or not ; and if they belong to it , then either to it alone , or to many other things as well as it : the propositions , too , which are deduc'd out of these , must be some proper , some common , some wholly accidentall and unconcerning . . amongst which , since proper ones alwayes expresse something which has the nature of a cause or effect , and an effect cannot exist without an actuall cause , nor an actuall cause without an effect ; such propositions are fit to conclude upon any subject , about which we are making inquiry , that it is , and cannot possibly but be ; to do which we call framing a science , and the syllogism whereby we work thus , a demonstration , and its conclusion , science : which , if we know why a thing is , that is , if the demonstration be made from the cause , both the knowledge and demonstration are call'd à priori , or from something going before ; if otherwise , à posteriori , or from something following . . common and vnconcerning propositions are both of this nature , not to be applied to the conclusion but by the convoy and mediation of some other closer relations ; which yet , lying hid and being undiscernable , are onely capable of affording an apparent knowledge call'd opinion . . from which rule , such propositions are to be excepted which assume for proof the knowledge of another person : for , since knowledge is adequate to the thing it self ; 't is , as it were , a proper accident : and the knowledge of a thing attain'd by these propositions is call'd faith. which kind of knowledge may arrive to a certainty , if the authority assum'd be out of all question : yet it is not science , because not evident ; since the thing appears but in the knowledge of another , and is undiscernable in it self , being it moves not the understanding by it self and things naturally connected with it . lesson iii. of the predicaments in common , and the three first in particular . . we have said that propositions are compos'd of notions ; and that a notion is the thing , according to the being it has in the vnderstanding : there are , therefore , so many kinds of notions as there are severall common habitudes of any thing without or within the understanding , whereby it may be referr'd to any other thing , that is , predicated of a subject . . now any thing may be considered both according to what it has in it self or is in its own nature , and according to other things which , by consideration , are drawn in and applied to it . and , as to its intrinsecalls , a thing is consider'd either absolutely and in its very self ; and so 't is call'd a substance , and that which is pronounced of it a substantiall predicate : or , as 't is compar'd to all other things , in that respect wherein all things agree ; and thus we ask , how big a thing is ? and what we answer concerning it is call'd its quantity : thirdly , 't is compar'd to those things which are of the same kind with it ▪ or to its own particular nature ; and so we ask , what manner of thing is it , that is , how perfect is it in its own nature ? and what we answer is call'd its quality : lastly , 't is compar'd to other particular things ; and we ask , what 't is in respect to another ? and the answer is call'd related or relation . 't is plain that , under these four heads , are comprehended all things considerable in the nature of any subject , that is , which are in it self . . but , those things , which are circumstantiall to another and may be referr'd to it , are either apply'd with motion or in rest . if in rest , the predicate is neither constantly fixt to the subject , nor the subject to the predicate ; and then we ask , where a thing is ? and the answer is call'd it's place : or else the subject is fixt to the predicate ; as a statue to its basis , liquour to a vessell , one that sits to his chair , &c. and , as before , we ask , where a thing is ? whereto the predicate we answer is call'd its site or situation : or lastly , the predicate is fixt to the subject , and we ask , what it has ? to which that we answer is call'd its habit , as garments , arms , instruments . . in motion , if the subject be mov'd , the agent alwaies accompanies it ; if it move , the patient : and , in both cases , time or the motion of the heavens goes along with them , from which no motion can be exempt . of this last , we ask , when was the motion ? and what we answer is call'd the time of the motion . . when the subject is mov'd , we ask , by what ? and that we answer is said to act , and the subject to suffer from it : when the subject moves , we ask , what it moves ? and that we answer is said to suffer , and it self to act. thus , the reason is evident , why there are just ten orders or classes of predicates , or notions , or beings in the understanding , which are call'd predicaments . . substance is immediately distinguisht into spirit and body . the differences of spirits are unknown . bodies are either living , that is , moving themselves , or dead , that is , not moving , but mov'd by others . living bodies are either sensitive , or without senses . sensitive are either intellectuall , viz. man , or brutall , beasts . man is either socrates , or plato , or xenophon , &c. and these are no farther divisible ; whence they are call'd individualls ; the rest vniversalls , because they are predicated universally of all that are under them , that is , of every one . . quantity is either discrete , as number ; or continu'd : and this , either permanent , or successive . permanent is twofold ; extensive , whose perfection consists in three degrees including one another , longitude , latitude , profundity ; and intensive , which is weight . successive quantity is contein'd in action , passion , speaking , and , generally , in motion . . concerning the proper nature of body , because 't is finite , we ask , of what figure ' t is ? because 't is alterable by others , we ask , how 't is , in respect to those qualities according to which 't is variable ? as heat , cold , colour , savour , &c. and this either constantly or in motion ; and we answer , accordingly , either by the passible quality or by the passion : as , in a feaver to be hot , or to blush for bashfulnesse , is a passion ; but to be of a hot complexion , or ruddy countenance , is a passible quality . again , because a body is ordered naturally to act and to suffer , we ask , what it can or cannot do ? and that which is answer'd is call'd its power or impotency . lastly , because every nature consists in a kind of temperature , we ask , whether it be well or ill in respect to that ; that is , whether it exactly or disproportionately possesses those things which are requisite to that ; and this , either constantly or for a time ? to which the answer is call'd , respectively , a habit or disposition . lesson iv. of the rest of the predicaments . . those things which relate or are compar'd to another , are either compar'd for having some notion common to both ; or for their acting or suffering ; or else , by a certain third way , which participates of both these : as , when a picture is made like the originall , that neither acts upon the picture , nor is the picture ( being wholy of another kind ) really like it , yet in a manner , 't is both : and this respect is call'd of the thing measured to the measure . . and , in this kind , there is one onely relation , and that on the side of the measured : for a relation being the order of one thing to another , and since , between two things , one may be so ordered to the other , that the other may either have or not have a coordination to it ; it comes to passe that those things which are in the same order ( such as are those two first kinds ) have a relation on both sides , but those that are of different orders , so that , notwithstanding , the one be ordered to the other , have a relation but on one side . . besides , it often happens that the understanding , through custome or an imperfect way of knowing , expresses even things that have no ordination , by a certain relative resemblance ; and then 't is a mentall relation ( by schoolmen call'd de dici ) not a reall one : as also , when the understanding has express'd the nature of any thing by a negation , saying , a man does not see , or has no hair ; and then gives a positive being to this notion , saying , a man is blind or bald ; according to the naturall aptitude or ineptitude of the subject to the denyed quality , 't is call'd a mentall negation or privation , respectively . . wherefore , since , by these only ways , the understanding can so vary any thing which it knowes , that a change may remain on the objects side , and enter into the consideration of it , as belonging to the thing known ; there can be three only kinds of mentall beings : for , the disputes of the moderns concerning such entities , are but gay trifles , and the contemplation of an erroneous definition . . there is a kind of relations , not unjustly , call'd intellectuall , which follows a thing in the vnderstanding in vertue of the reall quality of mere vnderstanding ; and these relations are of a logicall nature , as those terms of universall , predicable , subject , antecedent , consequent , & the like : and these relations as much follow out of things , in that respect , as they are in the understanding , as likenesse follow 's a thing in as much as 't is white , or equality because 't is quantitative : this , therefore , is call'd intellectuall , because the understanding is call'd intellect , and in no other respect . . an agent and a patient clearly expresse two causes : which , yet , the understanding ( distinguishing , & finding parts differently respecting the effect ) logically and to serve its turn for demonstration , divides into four . . and finding , in the agent , that it can and that it does act ; the understanding call's that whereby it does or can ▪ act the efficient cause , and that which moves or makes it to act , the end : likewise , in the patient , distinguishing what it is that suffers , and what it suffers ; it call's that the form , this the matter : satisfying , thus , these interrogations , from what ? why ? by what or how ? in what ? . plato adds an idea or exemplar : but , 't is clear , that what wants an exemplar cannot work without it ; and consequently , there is not yet an efficient cause . the species of these , and indeed of all the last six predicaments , are little us'd , and therefore omitted . lesson v. of the five predicables , and the signification of words . . hence 't is evident , there are two kinds or differences of predications : for some predicates of the same line or predicament comprehend others , and are predicated of them as an universall of a particular : but predicates of distinct lines are predicated of one another , as a thing superadded is predicated of that to which 't is apply'd . . predicates of the first kind are said to be predicated in quid or as the what ; being such as answer to the question , what a thing is ? and , if the predicate comprehends the full answer to that question , 't is call'd a species : but , if it only contains a part , so that other common considerations are comprehended under it , 't is call'd a genus ; whose compart or partner , equall to the species , answers not directly to the question what ? but , with the addition of what kind or what in particular ? supposing the answer to the question what already made by the genus : and this is call'd a difference . . the other kind of predication is apply'd to some things necessarily connected with the subject , which are call'd properties : and are strictly such , if they appertain to it alone and alwaies ; but , more at large , if they be deficient in these conditions . sometimes 't is apply'd to things , which may be both joyn'd to and separated from the subject , without destroying it ; and such are call'd accidents . thus are there five , commonly call'd , predicables , or porphyries five terms . . but , since notions are not communicated , but by the means of words ; and the same word sometimes is apply'd to severall notions , sometimes to one only : as oft as the same word , in the same signification , that is , meaning the same notion , is apply'd to more , 't is said to signifie or be spoken vnivocally . . a word which serves for severall notions has this property either by chance , as when in one language it signifies one thing , in others another ; and then 't is call'd purely equivocall : or else , of set purpose , 't is transferr'd from one notion to another ; and then 't is equivocall by design . . and , of this kind are those words which , by necessity or upon occasion , are transferr'd from one notion to another , by reason of the connection of the two notions or things , or in consideration of their being cause and effect to one another : as , when healthfull , which signifies the quality of that temper which is just fit and convenient to a sensitive creature , is transferr'd to signifie the quality of vrine , because such a quality in it is the effect of a due temper in the creature ; or to meat , because it preserves and produces that fit temper : or else for proportion sake : so the expression , to stand at the helm , is transferr'd from a ship to the governour of a city ; because , according to proportion , he does that in the city which a pilot does in a ship. . and , in such kind of words , the later signification includes the former : as , if you would explicate urine as healthfull , you must say , 't is such an urine as is the sign of health in the sensitive creature ; if , the governour of a city as standing at the helm you must say , 't is he that does that in a city which a pilot does in a ship. these words are said analogically , or by analogy , to signifie more things . . and thus the word thing or being is extended to those ten lines or predicaments before explicated : for , since a thing is that which has a being , the first predicament alone justly challenges to it self the title of a thing in this signification ; that is , as thing signifies an individual substance , which aristotle call's the first substance , suppositum or hypostasis , & , in rationall substances , the person ; for these names signify the same . . whereas the rest have no being , but are only affections and certain determinations of what has a being : for example , socrates or callias to be men , is to have a being & to be substances ; but callias 's being of the same nature with socrates , which we call a relation of identity , is not at all distinct from them , & consequently can have no being but in them , and that their being ; yet , 't is not according to this notion that they have their being : this identity , therefore , has a being , not because it , according to its own notion , gives a being , or is that whereby a thing has a being ; but , because 't is a notion which explicates a thing , that , according to another notion , has a being . . hence it appears why a consequence holds negatively , from a substance to all other things ; but positively , from other things to a substance : for , that which is not , can neither be the whole nor part of a thing ; and , if it be a part or a whole , if fitted to its own nature , if apply'd to others , certainly it is . . t is as evident , if any never so little mutation be made in the substance , the whole is chang'd : for , the substance being that notion whereby the thing is what it is ; and every mutation in substance changing that notion ; by every change made in the substance , that is chang'd whereby this thing is , and consequently , this very thing . lesson vi. of definition , division , and disputation . . to know whether a word be spoken univocally of more things , we must look whether it be predicated , still , according to the same notion : now , a notion is evidenc'd by a definition . a definition , therefore , is a speech compos'd of more notions , which , taken together , make up that one notion which before was not known . . since , therefore , a definition is the very notion defin'd , resolved , as it were , into parts : 't is clear , it can neither be more ample nor narrower then that which is defin'd . . again ; 't is plain , that , to ask a definition is nothing but asking what they mean , who understandingly use a word : wherefore , since some words expresse notions that are common to all mankind ( as , those of the ten predicaments ) 't is evident that , in these and such like , we must observe , what the common-people , who make up mankind , mean by such a word . . but , of proper names and terms appropriated to any discipline , to ask the definition is to ask , what the masters of that discipline mean by such a word ? for these are , as it were , the creatours and causes of the words . . again , 't is evident , he that asks a definition ought to collect the usuall sayings of the intelligent users of this word , that concern the thing as 't is expressed by this word : which , if they be all gather'd , 't is as demonstrable the definition is made right , as any cause can be demonstrated from its effects ; since , 't is plain , those sayings depend from the notion of the word as from their cause , and consequently , the notion of necessity appears in them . . but , if it happen to appear out of such sayings , that the word has more significations then one ; amongst those that are made by design , it will easily be seen which is the principall , because that signification will be included in all the rest : as , the soundnesse of meat or urine include the soundnesse of an animal . . again , since those things which are demonstrated concerning another are , either in the thing it self , or else are effects or causes of it ; both which appear in the thing it self , and are conformable and proper to it : now , a definition explicates the thing it self : 't is clear , that whatsoever is demonstrable of the thing is rooted in the very definition : whence , a definition is a certain principall instrument of science ; and all the solutions of difficulties depend chiefly upon definitions . . to make a definition right , the art of distinguishing must be learnt . for , a term being propos'd to be defin'd , out of what has been said , 't is easie to find in what predicament 't is : which once known , all that remains is , by dividing the genus , to descend by degrees , till you come to the particular in question ; when , presently , you have the definition . and if , as it sometimes happens , many severall genus's have a share in the thing to be defin'd ; this same course is to be pursu'd through them all . . but care must be taken , to divide by proper differences , that is , such as include in them the thing to be divided ; seeing they are nothing else but more or lesse of the very genericall notion : for accidentall differences are infinite , and besides the intention of him that asks for a definition . . have a care , also , the division be made by contradiction , that is , into parts contradictory one to another ; for so the divider may be sure he comprehends the whole genus . lastly , these rules being observ'd , the fewer members there are , that is , parts into which the genus is divided , the more exactly you proceed . that division , too , whereby accidents are distinguisht from their subject , is very usefull to sciences : for , when it appears that a concrete , that is , a thing which comprehends severall parts or notions , is the cause of any effect , by this division you come to that notion , according to which , precisely , 't is the cause ; which must necessarily be connected with the effect , simply speaking , and consequently , the effect may be demonstrated out of it à priori : for example , if it be known that policletus made a statue ; separating the accidents , 't will appear that he made it , not as white , nor as musicall , nor as policletus , but as one skill'd in such an art ; and hence you 'l collect , that all skilfull in that art can make a statue . . out of a division and definition made aright , there arise two sorts or species of self-evident propositions : for , as oft as one of the terms is a direct part of the definition of another term , the proposition is clear ; as , if a man be a reasonable creature , he is a creature : again , in a division truly made , 't is plain , the parts may divisively be pronounc'd of the whole ; as , when we say , a number is either even or odd. whoever aspires to sciences must be assiduous in these ; but , above all , in the practice of defining ; for , all the connection of notions is found in definitions , and the connection of terms is that which makes science . . these , too , chiefly detect the snares of equivocall terms , which are the very bane of science ; especially those which are caus'd by analogy . now , equivocation is display'd , by looking into words what way soever connected ; as , into causes , effects , contraries , superiours , inferiours , &c. wherein , if once any thing be found , which agrees to one and not to the other , the equivocation is discover'd : as , if a voice and a saw be both said to be sharp , but the contrary to the voice is flat , to the saw , blunt ; 't is plain that sharp is not predicated of them both in the same signification , and therefore 't is equivocall . . as for our modern disputes , 't is to be observ'd , that the defendant either puts a false conclusion ; or , if it be true , he holds another incoherent with it ; or , at least , if there be no opposition among his tenets , yet he is ignorant of the antecedents and consequents to his thesis ; or , lastly , he is perfect only at this thesis . in the two first cases , he may be convinc'd , if the disputant behave himself well : in the third , too , if the disputant can bring him about to yield to some falsity in those things he is ignorant of , he may easily convince him . . in the fourth case , one must dispute critically , that is , either something afarre off must be sought for , and forreign to the question , which the defendant is not oblig'd to be skilfull in ; and clapping authority on the back on 't , to fright him into the admission of a falsity ; which is the trick of most of those that dispute out of medium's from theology and the divine omnipotence : or else , one must argue out of common and logicall notions , in which both the terms are ambiguous , and equivocation easily hides it self . peripateticall institutions . second book . containing those things vvhich concern the nature of bodies in common . lesson i. of the composition of bulk or bignesse . evclide having demonstrated , that 't is possible to divide any undivided line , into full as many parts , as any other whatever has been divided , that is , into parts beyond any number assignable , that is , into infinite : there 's no farther doubt but a body or magnitude is divisible without end . . whence it follows , that one indivisible in quantity , added to another , makes it not bigger : for , if it did , a finite number of indivisibles would constitute quantity ; and consequently , a body would not be divisible without end . . again : since any multitude encreases by the addition of one to those already suppos'd , ev'n though 't were infinite : and yet the addition of one indivisible , to whatever presuppos'd number , makes it not greater : 't is clear , that neither an infinite multiplication of indivisibles is sufficient to make quantity ; and consequently , that a body or bignesse is not compos'd of infinite indivisibles . . moreover , since 't is manifest that , if any two parts actually exist in a body or magnitude , even all the parts into which a body is divisible do actually preexist in it , too ; and since 't is plain , if a magnitude were divided into all it were divisible into , the remains would be purely infinite indivisibles : 't is perfectly manifest that no two parts do actually exist in a body or magnitude . . 't is urg'd against the divisibility of a body in infinitum , that there would be infinite parts in it ; and since an infinite can never be measur'd , no part of a body can be pass'd over in a finite time ; and consequently , there can be no motion ▪ aristotle answers , that an actuall infinite can never , indeed , be pass'd over , but in an infinite time , too : but that the parts of a magnitude are only , potentially , infinite ; and , therefore , nothing hinders but they may be pass'd over in a finite time . galilaeus replies , as any two halfs do not , therefore , require lesse time to pass them over , because they are not separated : so neither can infinite parts ( supposing them in a magnitude ) be pass'd over in lesse time , because they are but possible , then if they were actually or in effect . . 't is answer'd , that if , in the potentiality of a magnitude , there were , really , infinite parts , whereof every one , limited in themselves and distinct from one another , had a determinate bignesse ; they would indeed require an infinite time to be pass'd over : but there 's no such matter : for , the parts of a magnitude have so undetermin'd a quantity , that they may be bigger or less , according to the proportion to the whole wherein they are taken ; whence , since , the more are put , the lesse they are , it comes to passe that they never exceed a certain determinate summe , which is the magnitude of the whole , how high soever they encrease in number . . again : 't is objected against this assertion of no parts being actually in a magnitude : first , that 't is against the credit of our senses , for , we see divers and severall parts of a table or stick ; our hands , too , and fingers are many . . 't is answer'd , by denying that we see many parts of a table or stick : for , if we saw they were severall , our sight could distinguish one from another , and we could just tell where one ends and another begins : since , therefore , the nearest immediate parts are separated , only by an indivisible ; and an indivisible cannot be discerned by sense ; 't is evident , it belongs not to the senses to distinguish one part from another . . and , whereas 't is added , that we see two hands and many fingers of the same man's : 't is true , indeed ; but a hand or a finger signifies not a part actually , but in potentia or possibility : for , if a hand or finger were cut off from the rest of the body , it were , now , no longer a hand or finger , since it would be no more an instrument of taking any thing , which is of the very definition of a hand or finger . . 't is objected , thirdly , those are actually distinct , of which contradictories can be verifi'd : but , 't is truly pronounced of divers parts of a magnitude , that this is seen , toucht , hot , cut , &c. whilst the contradictories to these are as truly said of another part ; nay , 't is really true , that this part is not that , as the hand is not the foot , an eye is not an ear : wherefore , these parts must needs be actually distinct . . 't is answer'd , that contradiction is only in respect of our understanding ; wherefore , the contradictories have only a notionall repugnance in the subject , as it is in our vnderstanding . since then , the parts have a distinct being in our understanding ; from thence 't is that they are capable to sustain contradictories : which to make plain , instead of this proposition , this part is seen , toucht , warm , &c. let us say , the thing , according to this part , is seen , toucht , warm , &c. and not according to that ; is it not clear the same thing sustains contradictories as 't is diversly apprehended by the understanding , because the understanding by this reflection , according , makes the same thing divers subjects . . the like 't is when we say , a hand is not a foot : for it signifies that a man as having the faculty of taking any thing , is not a man as having the faculty of walking . and the same rule , we see , holds in abstracted notions ; for , though we say , an animall is rationall , yet we say , animality is not rationality . lesson ii. of the nature of quantity and place . . parts , then , not being actually in a magnitude , it follows , that extension or divisibility is not accidentall to it , but the very nature of quantity : whence , we see , as oft as one asks , how much there is of such a thing ; for example , a way , a piece of cloath , liquour , &c. we answer , so many furlongs , ells , ounces , &c. that is , by the parts into which they are divisible . 't is plain , therefore , that the very nature of quantity is divisibility . . hence , again , 't is clear , that 't is not to be enquired how the parts of a magnitude come to be united : for , since more cannot be made of any thing , but what first was not more , or , one ; 't is evident , that what is divisible is , in that very respect , one ; and out of the very nature of quantity its parts derive an unity . . nor is it lesse manifest , that nothing , besides quantity , is extended and divisible : for , 't is not intelligible , that any thing can be divided , and yet have no divisibility : wherefore , that they call imaginary space is nothing at all , nor has it any distinguishable parts ; much lesse can it be a means of distinguishing other things , by its own distinction . . 't is objected , before the creation of the world , there was a certain possibility of a world ; and a greater of the whole world then of any part ; nay , even now , without or about this world , 't is possible other bodies should be created , bigger then this world : yet , such a body cannot be created , but some parts of it must be more distant from this , then others : therefore , a greater and lesse distance from the world is imaginable ; and consequently , an imaginary space . . 't is answer'd , there is , indeed , a possibility of such a world : but , 't is either in the power of god , and so is nothing else but his very essence ; or , in the idea of some understanding creature ( and is only the mere conformity of the predicate with the subject , or of one part with another ) which saies , there is a world , or such things agree well together . but , without the world there is no distance , now ; though there would be , were any new body created : for , since distance signifies extension and parts ; and a body is compos'd of parts ; 't is plain , that , a body being created , distance too , is created : but , to imagine distance abstracted from a body is manifestly against this first principle of reason , which denies that the same can be a thing and no-thing . . again , 't is evident , there 's no such thing as a kind of infinite magnitude or vastness , wherein all bodies are : for bodies would not be counter-extended with such a magnitude ; & consequently , since bodies are quantitative things , that would not be such . . out of what has been said , 't is plain , there is no empty place in the world ; that is , there is no hollow body , wherein there is not another body : for , it being determin'd , that distance is a body ; 't is manifest that , taking away body , all distance is taken away : since , therefore , 't is plain , that distant things are joyn'd by taking away the distance ; if , out of a hollow body , that be taken away which keeps the sides asunder , the sides remain conjoin'd , & the body is no longer hollow . . whence it appears , the wonder of those that ask , if all the air should be taken out of a vast hollow sphear , and nothing else should be done , what would follow ? is irrationall ; and signifies just as if they should say , if the sides of the sphear were joyn'd , & nothing else done , would they be joyn'd ? . if , then , all quantitative things are joyn'd together , they are continu'd : for , things continu'd are no otherwise , so , but , in vertue of the quantity , which is in either part : since , therefore , in these , there 's quantity on either side ; whatever quantitative things are conjoin'd must be continu'd . . out of what has been said , the notion of place is collected : for , it appears to us , that is , to mankind , that place is an immovable vessell , which some bodies go out of and others enter into : moreover , that the earth is absolutely immovable , and that heaven and the starres observe a constancy in their motion , & so give a ground , on which the notion of immobility may be founded ; whence , a vessell , by respects to a determinate part of the earth & of the motion of the heavens , will gain an apprehension of immobility . to say , therefore , a body is in such a place , is as much as to say , 't is in a body which has such a situation to the earth and to the heavens ; for example , 't is at such a distance from such a mountain , towards the beginning of aries , or the sun-rising . . and , that this is true , appears out of those explications of place , whereby , usually , answer is made to the question , where is such a thing ? for , we answer by such things as , in our apprehensions , are immoveable : in the last resolution , by the parts of the heavens ; next , by mountains , rivers , cities , houses , trees , &c. and more immediately by walls and things fastned to walls , or rather , by immoveable things within the house , as beds , cupboards , &c. 't is plain , therefore , that place is the body which next encloses the thing within it ; as 't is conceiv'd to be in a certain site to the rest of the world , or its fixt parts . . you 'l object , there 's nothing constant in the world , able to make a place , besides imaginary space . 't is answer'd , place is a word , signifying according to the will of the first imposers , and therefore signifies a thing as 't is in our mind , or under notion ; wherefore , you must not require something really immoveable , but which may appear such : now , even motion it self , if it be constantly the same , appears to have a kind of immobility ; and so , 't is sufficient that the sun constantly rises in one part and sets in another , to determine place , without any need of imaginary space . . you 'l object again , this definition does not agree with all things that are in place : for it neither agrees with angels or separated souls , which yet , 't is clear , are in a place ; nor with the world it self ; nor with qualities ▪ or parts of substance , which are in a place , too . we answer , 't is clear indeed that spirituall substances are in a place , but 't is not clear what signifies , to be in a place , when we speak of them : but certain 't is , that it signifies not , to be in a place after the manner of bodies , which alone is , properly , to be in a place ; since mankind , to whom belongs the imposing the name of place , never saw spirituall substances . 't is as certain that , either the world is not in a place , or , if it be , ( as some endeavour to explicate , ) 't is by its parts ; that is , because every part is in a place , it may , in a kind of forc'd sense , be said to be in a place . but , forms and qualities to be in a place , signifies they are the forms and qualities of bodies which are in a place : whence , all these are said to be in a place analogically , and not in their primary signification . . nor imports it , that the vulgar think that to have no being , which is nowhere : for the vulgar are not the composer of sciences , as they are the imposer of names : wherefore , we receive the signification of names from them , but not the truth of propositions . . having determin'd then , that place is something extrinsecall to the thing in it ; and seeing that an extrinsecall change cannot be made without some intrinsecall one , too , ( since the extrinsecall denomination is not another thing , different from the intrinsecall quality of the things which concurre to the denomination ) in every change of place , some intrinsecall mutation must of necessity intervene : but , the change of place is , immediately , a change of the application of the sides of the thing moved , from the sides of the place whence it parts , to the sides of the place whether it passes : wherefore , the place and the thing in it being , really , the same quantitative thing , we must say that locall motion materially , is division , that is , the first and , principall act of quantity or divisibilty ; and , formally , the denomination of a new site of the universe , as has been declared . . it follows , out of what has been said , that , since 't is of the very nature of quantity , to have its parts extended and one out of or beyond another , 't is impossible two bodies should be in the same place ; for so , one , in respect to the other , should not have the nature of quantity : as also , if the same body were situated in two places ; since 't would make a double distance , it would have the force and effect of two quantities , that is , be double it self . . the objections against these positions are theologicall , & not hard in theology ; & therefore , are to be referr'd thither . lesson iii. of time and locall motion . . now , among locall-motions , 't is evident , the motion of the heavens , especially of the sun and moon , is most notorious and common to mankind ; as also , ( at least , to our apprehensions ) most constant & equall : wherefore , t is the fittest & best qualifi'd for the measuring of other motions : & so , experience teaches , that 't is apply'd to this use ; for the howers , days , years , &c. are certain parts of the motion of the sun. . this motion therefore , as 't is made use of for the measuring other motions , we call time : and , comparing motion to time , we say , one is swifter or slower then another . . you 'l object , this is an ill definition of time : for , before the world was created , there was time ; and yet , no motion of the heavens . if the sun , too , should stand still , time would not , therefore , cease to passe on : wherefore , time is not the motion of the heavens . 't is answer'd , before the creation of the world , there was no time ; however we may imagine time before the world , as we do place out of the world : but these opinions are ill grounded in the fancy . and , if the sun should stand still , 't is plain , there would be no daies and years , &c. that is , if it should stand still for ever ; for , if it stood but for a little while , it would only make the day longer . but , 't is to be observ'd , that the motion of the heavens is not time , as it is in it self , but as it is the object of our apprehensions ; whereby we form a certain quantity of motion , which we may apply to all other motions , and even to the motion of the sun it self . . to the question , therefore , whether time would passe on were the sun or heavens immoveable ? 't is answer'd that , abstracting from our apprehensions , it would not : but , because there would still remain in us a power of measuring other motions , by the motion of the heavens which we formerly apprehended ; we should measure motions by time passing on in its essence , not in existence , that is , by the notion and nature , not the actuall presence of time. time , therefore , would not , really , passe on ; yet we should make use of it as if it did . . you 'l object again , the motion of the heavens is divisible , as the space wherein they are mov'd : but time consists of indivisibles ; for , it has no true being but the present , which is alwaies indivisible . 't is answer'd , time is divisible without end , just as motion is : but , what is said , that nothing of time is present but an instant , is false ; for , we say , the present day , year , age , &c. for , time being motion , as in our apprehensions , the understanding can make as much of it present as it pleases , by taking a whole part after the manner of one entity . . but an indivisible part of time is never present ; for , there is no such thing : the working , only , of our understanding makes instants , not as a part of time , but as the end of one part and the beginning of another : whence , we never conceit an instant in time or motion , but when we mean there is no more time or motion , an instant , therefore , is a kind of not-being of time : wherefore , what 's said , that nothing of time is present but an instant , is to be understood , that nothing of time is present together and at once , because its nature is successive ; nor can it have any existence , as a kind of thing or being , but as the variation of a divisible thing as 't is divisible . . again ; it being apparent , that some things are more easie , others harder to be divided , or ( which is the same ) some are more , others lesse divisible : if that which causes the motion forces a lesse against a more divisible , the more divisible must of necessity be cut asunder , and admit in the lesse divisible between its parts : wherefore , a division will be made , and consequently , if the other requisites concurre , a locall motion ; for , the lesse divisible will change its place . if , therefore , the same lesse divisible be impell'd , with the same force , against any thing more divisible then the former ; 't will separate it in lesse time , and consequently , 't will be mov'd faster . . now , the lesse divisible is call'd , dense ; the more , rare : and , because divisibility is the very nature of quantity , the rare will have more , the dense lesse of quantity : and these are the first differences that can be expected in a quantum or magnitude , they being made by more and lesse of quantity in a quantitative thing . . but , because , out of what has been said , it appears that the rare , in respect of the dense , is that which is divisible , and contrarily , the dense is the divider : by how much greater the proportion of density is in the divider , to the rarity of what is divided ; by so much the division must needs be quicker , and the motion swifter . . in like manner it is , too , for matter of the figure or shape : for , one figure being apter to divide then another , ( since , we see artificers chuse sharp figures to cut with ) by how much the figure is more apt ( supposing all other circumstances proportionable ) so much swifter the motion will be . . lastly ; because , in dense things of the same figure , the comparison of density to the figure is greater in great things , ( because , in bodies , the solid is multiply'd in a triple proportion , but the superficies only in a double ; that is , of two similary globes , &c. if their diameters be as to , their solids will be as to , but their superficies only as to . ) it comes to passe that , ( other circumstances being suppos'd equall ) of bodies that are alike , the greater move swifter then the lesse . it appears , therefore , that , in respect to the same medium , there are three conditions in a moveable , which make the motion swifter , viz. bignesse , density and figure . . it follows , out of what has been said , that there can be no motion in an instant , by an agent of a finite power : for , the space wherein 't is made being divisible without end ; if the motion were in an instant , the agent could move the movable through a space assign'd , while the power which moves the sun could not move that never so little a space : since , therefore , space may diminish without end , 't is necessary the power be encreas'd without end , and consequently , be infinite . . again ; since a greater power is requir'd to move the same movable more swiftly through the same medium ; a movable cannot be transferr'd from a lesse to a greater degree of velocity , in an instant , by a finite agent : for , since some power is requisite to give it a greater velocity , even in the same time ; and the proportion of time to an instant is infinite ; the power to give it such a velocity , in an instant , must be infinite . . whence , 't is evident , that every movable which is rais'd from rest to motion , passes through infinite degrees of slownesse , greater then that degree whereto we suppose it to be arrived . for , since every assign'd degree is divisible into infinite ones which are between it and rest , nor can a finite agent raise the movable from any of those to an assign'd degree , in an instant ; much lesse can it transferre it from rest to an assign'd degree in an instant . consequentially to these positions , every movable that is reduc'd from rest to motion , at the beginning , increases in velocity : but , since to every finite agent , there corresponds a certain determinate degree of effect , beyond which it has no power ; when it arrives once to that degree of velocity , it will stand at it , and the motion will encrease no farther . . but if , to the difficulty of the medium , there be added an agent moving a contrary way ; according to that agents power the velocity of the former movable will be diminisht , or the movable be even forc'd to rest , or to an opposite motion . and thus it appears how motions begin and end . . lastly , it may be concluded , speculatively speaking , that any weight whatever may be mov'd an assign'd space , by never so little a power : for , since the power must , of necessity , be multiply'd to encrease the velocity ; as much as it fails in velocity , so much may be abated in the power . assigning therefore a bulk to be mov'd and a power to move it ; suppose another power which may be able , in a certain time , to move this bulk such a determin'd space ; and , by how much this later power is greater then the first assign'd , somuch encrease the time in which the movable should be mov'd through the propos'd space ; and because , now , the effect is so much lesse , it will not exceed the power assigned . . i said , this is speculatively true : because , when one should go about to reduce it to practice , an extremely little power could not be preserv'd so long time , as were necessary to the effect . lesson iv. of the four first qualities . . out of what has been said , it being concluded that rare and dense are the first differences , and that they by consequence , like quantity , are varied with endlesse differences ; seeing , too , that there is a perpetuall tumult as it were , in the world , of heavy things descending towards the centre of the earth : there must , of necessity , be some degree of rare bodies so easily divisible , that it needs nothing , but this very impulse , to separate their parts , & carry them , the nearest way to the centre . . such bodies , therefore , will spread themselves without any limits about the earth , unlesse they be hindred ; whence , they 'l have no proper figure of their own : but when they encounter with a denser body , upon which the impulse that divides them , has not the like power ; there they 'l stop their division , and receive a figure from that . . they will , therefore , be easily terminable by others bounds , hardly by their own : but , on the contrary , bodies , upon which the motion of gravity has not such force , will be easily terminable by their own bounds , hardly by others . now , this , nature and aristotle have assign'd for the notion of drynesse , that , of moysture ; wherefore , these will be dry bodies , those moist . . it appears , therefore , both that all bodies , that have a consistency , are dry ; and that , if there be any so rare , that , by all others , it will be repell'd from the centre , ( that is , rare in the highest degree ) that , too , is dry ; for , its parts take not easily their ply , that is , are not spread by the falling of heavy bodies , but are carried by their own motion : yet , that which is dense in the highest degree will be more dry ; because the rarest receiv's a figure partly from those without it , partly from it self . . but , among moist bodies , that which is rarer is moister ; as more yielding to the gravity which divides it . . you 'l object , that dust and fire accommodate themselves to the bounds of other bodies ; and , therefore , must be moist . 't is answer'd , dust is not one body , but many : besides , it does not so accommodate it self ; since , if it lye free , a heap of dust is full of aire , by which it is rendred so easily plyable . fire , too , has a proper motion , and is reflected , when forc'd by a hard body ; nor does it wholy accommodate it self , as appears in light and the flames of furnaces . . again ; since , by the same motion of heavy bodies , rare ones must necessarily be press'd against dense , and dense against rare : if a very rare body be so forc'd against a dense , that it be constrain'd to make its way ; since , 't is divisible into minutest parts , and 't is easier to make a narrow then a wide way ; 't is plain , the rare body will bore it self a world of little passages and paths , and consequently , will dissect the dense , which opposes it , into an infinity of little parts . . whence , it follows , that , if there were many heterogene bodies , ( that is , of a different nature ) shut up in the dense body ; all , now being set at liberty , by such dissection , will , by their proper motions , gather themselves to their own parties , and be separated , every one , from those of another kind . . but if a dense body compresse a rare one , 't will let nothing scape out of it ; but , whatever if finds , it condenses and crowds into a narrower room . . dense bodies , therefore , have this nature , to gather together heterogene bodies ; that is , they are cold : and rare bodies , to gather together homogene ( or bodies of the same kind , ) but to disperse heterogene ; that is , they are hot . for , nature and aristotle have given us these notions of hot and cold . . and among rare bodies , 't is apparent , the rarest will be the best dividers , that is , the hotest : but , among dense bodies , those will be the coldest , which most streightly besiege the rare bodies , and those are such as are most plyant to their parts ; whence , they which are , in some measure , moist , too , will be the coldest . lesson v. of the elements . . we have deduc'd , therefore , out of the most simple notion of quantity , dissected by the only differences of more and lesse , the rarest body , hot , in the highest degree , and dry , but not in the highest degree ; the densest , dry , in the highest degree , and cold , but not in the highest degree ; a heavy or lesse rare body , moist , in the highest degree , but not so hot ; lastly , a moderately dense body , cold , in the highest degree , but temperately moist . . these same bodies , in as much as motion proceeds from them to others , are active ; but , in as much as they sustain the action of others , they are passive ; chang'd , thus , in name , not nature . . this property also , of an element , they have , that they cannot be compounded of other things , and all things else are compounded of them : they being establisht out of the first differences which , of necessity , are found in others . there are , therefore , four elements . . you 'l object ; since rare and dense vary the quantity , by the very nature of quantity there will be infinite degrees ; and , thence the number of the elements will neither be four nor , indeed , finite . 't is answer'd ; men do not determine the kinds of things , according to the fruitfulnesse of nature ; but , by grosse and sensible differences , according to the slownesse of our apprehension . . thus , therefore , a rare body , which makes it self and other things be seen , we call fire : one that has not this vertue , and yet hinders not other things from making themselves seen , we call aire : a dense body , which absolutely excludes light , we term earth : one that partly admits it and partly repells it , we term water . . not , that wise men esteem these very bodies to be truly elements , which we are conversant with round about us : but that , these mixt bodies obtain that name , out of the predominancy of some element in them , which they would deserve , if , drein'd from all dregs , they were entirely refin'd into the nature of the predominant . . the elements , therefore , are bodies distinguisht , purely , by the differences of rare and dense : and they are collected into four kinds or heads , under the terms we have given them . . moreover , 't is evident , that no bounds or figures do , properly , belong to the elements , out of their own principles , that is , precisely by their own nature : for , since they are nothing but quantitative bodies , affected with such a rarity or density ; the nature of quantity still remains , which is every where divisible and terminable , and consequently , figurable as one pleases . . but , whether there be not some greatest possible bulk in every one of the elements , out of the very nature of density , depends upon metaphysicall principles . neverthelesse , out of their common operation , a sphericall figure is most agreeable to earth and fire . to fire , because its nature being to diffuse it self , with the greatest celerity , out of a little matter into a great breadth , it must of necessity spread it self on all sides , that is , into a sphear . . to earth , as being the basis & foundation , about which moist bodies diffuse themselves ; and , by so doing , mold it into a globe . . but , that fire flames up like a pyramid , proceeds from the resistance of the aire incompassing it , which 't is forc'd to penetrate with a sharp point . . again ; since the elements are oppos'd to one another , only by the differences of rare and dense : 't is evident , their transmutation into one another is nothing else but rarefaction and condensation . . 't is plain , too , that dense things , being forc'd against rare , do compresse them , and , if there be no way to escape , do necessarily condense them : which condensation , if it be enough both in time and degree , will , of necessity , change that which is condens'd , into that element to which such a density is proper . . but , a rare body compress'd , if it get out , diffuses it self a main out of those straights : whence , if any dense body , that is rarifiable , stick to it , it carries it away with it , and rarifies it : 't is plain , therefore , that 't will turn it into the nature of the rarer element ; if the other circumstances concurre which are necessary to action . . out of all which , we may collect , that one element cannot be chang'd into another , without being transferr'd through all the intermediate degrees : as if you should endeavour to rarifie earth into fire ; first you must raise it into water , then into aire , and at length into fire . . for , as we have demonstrated , above , concerning velocity , that a movable cannot be rais'd out of one into another determinate degree , but in time : so , with the same labour , the same may be made evident , concerning density ; since , the nature of quantity is equall and constant in both ; and velocity is nothing but a certain density of motion . lesson vi. of mixtion , and the second qualities , or those vvhich most immediately follovv mixtion . . since that part of the world , which is expos'd to our knowledge , is finite ; and any never-so-little bulk infinitely repeated , exceeds the greatest possible : it follows , that the singular bodies of this part are finite , and some actually the least : nay , that , according to the order of the world , bodies cannot be divided beyond a certain term . . there will be , therefore , in each of the elements certain minutest parts , which are , either not at all , or very seldome , farther divisible . when , therefore , the elements are forc'd one against another , the sides of the rare ones must , of necessity , become united with the sides of the dense : but , when they come to be divided again , 't is impossible they should not leave some of those minutest parts sticking to the dense bodies . . for , since , in the same quantity , the dense part is lesse divisible then the rare ; that , too , which is compounded of rare and dense , in the same bulk , is lesse divisible then the rare part of the same quantity : it must needs be , therefore , that the rare elements must stick , by their minutest parts , to the dense which they have once touch't . . hence , 't is evident , that the minutest parts being rub'd off on every side , by the ouching together of divers elements , mixt bodies must necessarily be made . for , if two dense parts touch one minutest rare ; since the minutest is indivisible , there naturally emerges a compound of the three , as hardly divisible as are the dense ones themselves . . whence , we have the first distinction of bodies : for , since the elements are four , and may be joyn'd together by bigger or lesse parts ; as oft as great parts of one element redound , the body is call'd by the name of that element . . thus have we severall kinds of earth : and , in this sense , all consistent things have the notion of earth ; all visible fluid things are call'd waters ; and there are many kinds of airs and fires . . but , when a body , that has the consistency of one element , is full of minute parts of another ; the substance of one element gets the denomination of the other's quality : thence proceed the degrees of temperaments , hot , cold , &c. and in one and the same kind , too , reduplicated differences of the elements ; viz. of earths , some are earthy , some watry , some aeriall , some fiery ; and so in the rest , ev'n to the lowest species . . it appears , again , wherein consist those qualities , which distinguish bodies , as to their consistency . first , the notion of liquid & consistent plainly follows the nature of rare and dense : and soft is a middle between liquid and hard ; but hard , being that which resists division , clearly refers to density . . but grosse and massive appertain to the quantity of parts : for grosse is not , so , divided into minutest parts , as to be able , by its subtilty , to enter into the least pores or crannies ; and massive has no pores or passages in its body , but speaks parts constipated and thrust close together : both of them plainly expresse a certain notion of density . . as for fat , and tough , and viscous or slimy , they have this common to them all , to stick where they touch : but fat , in lesser parts ; viscous , in greater ; tough , properly , holds its own parts together , and cleaves not so much to others . . they , therefore , consist of moist and dense well mixt : from moist they derive the facility to unite ; from dense , the difficulty to be separated . lesson vii . of the manner of mixtion , and the passion of mixt things . . these things being suppos'd ; because there are two active qualities , heat and cold , which are most eminent in fire and water : let there , first , be a mixt body of earth , water , and aire , upon which fire be suppos'd to act : and , since there is no mixt thing so compacted , but , at least , some parts of fire may be forc'd and fly away through it ; and they , in their passage , are joyn'd to the parts of aire or water : 't is apparent that the fire will carry away some of them with it ; whence the compound will become more compacted and solid . . again ; because the parts of fire are extremely subtile ; whereever they find a resistance in the solid parts , weaker then their power of dividing , that way they 'l escape , and that , not alone , but laden with watry or airy parts : so that they will leave the water and aire to be united with earth and between themselves , by the smallest parts that are possible . . whence , two things come to passe : one , that the whole becomes a like and equall throughout , all the elements being mixt by most minute particles in every part : the other , that the elements become lesse divisible from one another in this whole ; which is , to be rendred constant and permanent body . . let therebe , therefore , in another body , the natures of fire , aire and earth blended together ; to which let water be added from without : and , first , you 'l see all the sallies block'd up , and the pores coagulated by vertue of the cold , so that the aire or fire cannot easily steal out . . see , again , the water with all its weight and force , pressing the nearest parts of the compound on every side : whence , they are forc'd to compresse and streighten themselves , and shrink into a lesse and lesse place , to make room for the water ; and this , not in the surface alone , but even in the minutest parts , as far as the water can pierce ; which so much the farther it can , as its parts are rendred more subtile , by the re-active power of the aire and fire . . behold , therefore , its parts being , even thus , condens'd , a consistent and hardly-divisible body made ; which is , to be a certain naturall species of physicall mixt body . . hence , again , the causes of passions are apparent : for , we see some compounds suffer from fire a liquefaction and dissolution into minute particles ; as , into ashes and powder : others , on the contrary , grow hard : others , again , converted into flame . . the reason whereof is clear : for , if the power of the fire extends it self only so far as to dilate the humid parts which hold together the dry ; it comes to passe that the humid parts become larger and more rare , and consequently , the whole it self is rendred more divisible and subject to be diffus'd , by its own gravity , into the best ply towards the centre ; which is , to be liquid . . but , if the power of the fire be so great , as to carry away with it the humid parts ; then the dense ones remain resolv'd into minute particles , without a medium to unite them . and these operations are effected , sometimes by the mere force of the fire it self ; sometimes by means of some instruments , whereby the humid parts are either increas'd or decreas'd , according as the artificer has occasion . . but , farther , if humid parts were redundant in the compound , and fire were so far apply'd , as only to restrain the excesse , by exhaling those parts which were superfluous ; the connection of the humid with the earthy parts will be lesse dissolvable , and the proportion of the earthy to the humid , greater ; whence , the compound grows hard . . water , too , by pressing upon it , pierces and enters into the compound it encompasses , sheir's off its lighter and dryer parts , which it mingles with the whole dry body , and amplifies the humid parts : whence , it makes the body flaccid and loose , and next door to dissolution . . some it utterly dissolv's ; as salts : for , they are compos'd of certain minute parts , betwixt which water easily enters ; and , so little they are , that they swim in the water . there becomes , therefore , a kind of fluid body , thickned with little heterogeniall bodies swimming in it ; to which if fire be apply'd , by exhaling the superfluous humid parts , it remains salt , as at first . . but , sometimes it happens , that something is mix'd with the salt & water , which has a power of separating the watry parts from those little swimming bodies , and of pressing down & precipitating them to the bottome : for , when the supervener has aggregated to it self the parts of that humid body wherein the dissolution was made , that which was mixt with them ( if it be heavier then water ) descends ; for , before , it was sustain'd by its conjunction to the water which was lighter . . there are bodies , too , which grow harder and are petrify'd by the mixture of water ; either because there wanted moisture to make them coagulate , as it happens in dry or sandy bodies ; or because , by the addition of the extrinsecall moisture , the superfluous humour is suck'd out , in which their inward parts were dissolv'd and rendred flaccid ; or , lastly , because the pores of the compound being constipated without , the internall heat better dries the inward parts . . but , when the redundant parts are so very minute in themselves that they are easily rarifyable , they are diffus'd into flame . and these parts are such as we call fat or aiery , which consist of a thin moisture compacted with minutest dense parts . . it falls out , too , that , when the fiery parts within are many and happen upon a convenient moisture , they multiply and encrease themselves without any apparent extrinsecall cause , and open themixt body it self , so that the vessell cannot contain it , but it boyls and runs over ; as we see in the must of wine and of other fruits : and this kind of action is call'd fermentation . . sometimes , too , it blazes out in fire and flame ; as appears in hay , and other dry bodies moistned and crowded together : which comes to passe , by the fiery parts of the dry'd bodies turning the humid parts into fire , and , at length , by their multitude and compressure , raising a flame . . passion or suffering from earth is when , either by its weight or some other pressure and hardnesse , a change is made ; which , even by this , is understood to be a division , and , commonly , is wrought two ways : for , either the parts of one body are intirely separated , by the interposition of another body of another nature ; or else , only some are joyn'd to others of the same nature , as it happens in liquids when they are swash'd up and down . . the first of these divisions is made severall ways ; by breaking , cutting , cleaving , pounding , and the like ; the other , by hammering , drawing , impression , bending , compression , and the like : all which appear in themselves to be made , by the motion of hard and dense against soft and rare bodies . lesson viii . of impassibility , destruction , and the accidents of mixt bodies . those bodies which are esteem'd not to suffer at all , that is , no losse ; as gold , though it melt , yet consumes not ; the asbestus stone is purifi'd by flames and not endamag'd ; hair grows not more flaccid , that is , its parts are not more loos'ned , with water ; the adamant is so call'd , because neither the hammer nor fire can master it : these have got a name , through the unskilfulnesse of artificers . . for , the moderns have found out how a diamant may be resolv'd to dust , nay , even melted : as also , how to make gold volatile : the asbestus , in the very stone , both suffers from a very violent fire , and , when divided into hairs , is able to resist only a moderate one . . it appears , consequentially , what must necessarily follow , if fire be apply'd to a confirm'd and establisht body : for , since some parts of a compound are moister then the rest , the first efficacy of the fire will be exercis'd upon them ; with which , if there be any fiery parts mix'd , those first fly out with the fire , and are call'd spirits . . the next are the moist and more insipid parts , and they are call'd flegme : then , the more concocted parts , in which earth , fire and water are well mix'd ; and they are call'd oyls or sulphurs , and need a strong fire to extract them . . that which remains uses , by the chymists , to be washt in water : wherein they find a more solid part , which sinks down , and this they call salt ; and a lighter part that swimms a top , which they throw away as unusefull ; notwithstanding , 't is dry in the highest degree , and very efficacious to fix fluid bodies . . but , if a compound of these two be throughly bak'd in a very strong fire , the moisture of the salt is liquifi'd , and the other being clasp'd into it , and , as it were , swimming in it , so condenses it into a porous body , that it remains alwaies pervious to fire : and such a body is call'd glasse or vitrify'd . . whence , 't is clear , that these bodies are in part , made , and , in part , resolved or extracted by the operation of fire : and that they are not elements , but compounds , containing the nature of the whole , as appears by experience . . out of what has been said , it may be understood , what a mixt body is , viz. a body coagulated of rare and dense parts , in a determinate number , bignesse , and weight . . and , when many such unite into one , a certain homogeneous sensible body emerges , serviceable for mans use ; though it be seldome so pure , as to be unmixt with others . . hence , again , it appears , that it concerns not a mixt body , of what figure it be : since , with the same proportion of parts , it may be of any ; especially , when one body is compos'd of many little ones . all things , therefore , receive their figure from the circumstances of their origination . . for , since the same things must be produc'd after the same manner ; and those that are divers , different ways : the variety of manners occasions the variety of figures . . for , that which equally dilates every way , becomes spherical ; that which dilates irregularly , becomes like a bowl ; that which faints in growing longer , becomes like a top. . that which cannot extend it self in length , becomes parallelly flat ; that which is , in some part , defective in breadth , becomes a hexagon , a quadrate , &c. that which cannot dilate it self in breadth , becomes oblong . and thus , at large , and in generall , 't is evident , whence proceed the figures of mixt bodies . lesson ix . of the motion of heavy and light bodies , and the conditions of acting . . from what has been said we collect , that , since the sun either is fire , or , at least , operates like fire , beating upon earth , water , and all other bodies , with its rayes ; it summons out little bodies , which , sticking to its rayes , are reflected with them and mov'd from the centre towards the circumference . . by whose motion , all the rest must , of necessity , presse towards the earth : and because the motion of dense bodies is so much the stronger , the denser they are ; and descending bodies , the more they descend , the more they repell lesse descending ones ; there must be , wheree're the sun has any power , a motion of dense bodies towards the centre and of rare towards the circumference ; as experience teaches us there is . . whence , first , we see , there can no where be any pure elements : since , at least , the rayes of the sun and the bodies carry'd about with them are mingled every where . . we see , too , that dense bodies are heavy , and contrarily , rare are light : and that there is not any inclination requisite in bodies , towards the centre ; as is evident by the experience of pumps , by which , with an easie motion , a great weight of water is rais'd ; or , as when we suck a bullet out of the barrell of a long gun. . we see , moreover , that , since this tumult , of little bodies ascending and descending , swarm's every where : place any body in it , it must needs be press'd upon by others every where about it ; and the bodies , which are aside on 't , must perpetually pierce and enter into it , if they find in it lighter bodies which they can repell from the centre : whence , this tumult is even within all bodies , and , by vertue of it , all bodies are mingled . . whence , again , it must needs be , that the thin parts of every body consist in a kind of perpetuall expiration ; and consequently , that every body , more or lesse , operates upon and affects other bodies which approach it round about , or acts in a sphear ; as we see by experience , in hot , cold , odoriferous , poys'nous bodies , and in animals , &c. every body , therefore , has a certain sphear of activity , by this motion ; and its action depends upon this action . . again , therefore , since its action is not effected but by an emission of its own parts ; 't is plain , it cannot act upon a distant thing , but by a medium ; as also , that it suffers from that upon which it acts , if it be within that 's sphear of activity : the emanations of the one running , by lines different , from the emanations of the other . . again , 't is evident , that , since these emanations are certain minutest particles ; in a denser body more will stick to its parts , because its pores are narrow and hard to passe through : wherefore , with greater labour and time , and at the cost of more little particles , a dense body receiv's the nature and similitude of the body acting upon it , retains more strongly , and works more vigorously then if it were rarer . . and , hence , the nature of intension and remission is evident ; viz. because there are , within the same space , more or fewer of these particles : as also , why , in a denser body , a quality is more intended . lesson x. of the motions of vndulation , projection , reflection , and refraction . . 't is consequentiall to what has been said , that water , stir'd and alter'd , by any violence , from its planesse and equidistance from the centre , will not suddenly cease its motion and return to rest , though that extrinsecall force be withdrawn : for , since , by that violence , some of its parts are rais'd higher then they should be ; 't is manifest , that those higher parts , by the course of common causes , must presse towards the centre , and , consequently , thrust others out of their place : wherefore , the motion will continue , 'till every one be restor'd to its own proper place . . and , because ther 's no motion without a concitation and a certain degree of velocity ; therefore , by the very stop of the motion , a new motion will be occasion'd , but weaker and weaker still , till it quite faint away . . 't is plain , too , that the very same must , of necessity , happen in aire , if its parts be either condens'd , or stir'd out of their right place . . again , it appears that , if it be thus with the aire , the same must be expected , too , of any weighty moveable that 's carri'd in the aire : for , since the reason , why such descend not perpendicularly , is , because the progressive motion or the causes of it are stronger then the causes of descent , at least in part ; and , since the moveable has , of it self , no inclination this or that way ; it must needs follow the motion of the aire that 's next it . but , since a dense thing mov'd is carri'd more forceably , then a rare body in which it is ; the rare body it self , as it gives a beginning to that 's motion , so , again , it receiv's an advance from that : whence it comes to passe , that both the aire and the moveable continue their motion longer then the aire alone would . . hence , again , it appears , that moveables ( in all other respects alike ) the denser they are , the longer they retain their motion . . 't is plain , therefore , why pendents by a thrid fastned above wave up and down , if they be rais'd from the perpendicular and then let drop : for , with their first descent , they move the aire , following it when it ascends and returning with it when it returns , but with a new and a weaker impulse : and so proceed still , till they can stir it no longer . . it appears likewise , that , if a moveable be violently struck against a hard resister : because the aire before it must , of necessity , yield , and that which follows it pushes it on ; it will follow the aire before it , that is , 't will be reflected from the hard resister . . and this , making equall angles , at least without any sensible difference : for since an oblique motion is resolv'd into two perpendiculars , which are in a certain proportion , by vertue of the moving causes , and the angle is caus'd and emerges out of this proportion ; it must needs be that , this proportion remaining , the angle of the result or reflection must needs be the same with that of the impulse or incidence : as in light , where the reflection diminishes not sensibly the force ; but , where the reflection notably weakens the force , the angle of reflection will be proportionably lessen'd . . but , if the resister do but partly resist and partly admit , that which is obliquely mov'd will be refracted ( as they call it ) from the resistance towards the contrary part ; that is , at the entring , towards the perpendicular falling from the mover upon the superficies ; at the going out , from the perpendicular ; as experience , conformable to reason , witnesses . . you 'l object , that refraction of light and dense bodies is very different . i answer , all the experiments i have ever heard of , conclude no such thing . . the cause of restitution is , that those bodies which recover themselves again are chang'd from length to breadth : but , 't is known , an extrinsecall superficies , the more equall dimensions it has , the greater quantity 't is capable of ; whence , the more the longitude exceeds the latitude , so much the more the parts of the imprison'd body are compress'd , whose motion is so much the swifter as they are the more spirituous , and so much the easilyer , too , they are dilated and rarifi'd after they have been compress'd and condens'd by the circumstant causes : and this is that we call restitution . . but , it ordinarily happens that , if they stand too long in bent , they recover not themselves again afterwards : because , either the condens'd parts are rarifi'd , by the expulsion of some of them ; or else time has begot some stiffnesse , by the concretion of the parts press'd together , so that now 't is not so easy for them to return to their former habit . . this doctrine is evident , to the very sight in flesh ; which , being press'd , becomes white , the bloud retiring ; but when that returnes , it comes to it self again and recovers its colour . but steel , above all things , most swiftly restores it self , because it has a many extremely spirited particles imprison'd in it . lesson xi . of the electricall and magneticall attractions of hot bodies . . out of what has been said , 't is again deduc'd , that , since there 's a perpetuall issue and sally of some parts , out of bodies abounding with intense heat ; and , thereupon , a certain orbe of steams : other little bodies must , of necessity , flow in , after the same manner , to the body it self ; and consequently , there must be the same tumult about every such body ; les . . . as we spake of about the earth . . hence , we see that hot bodies naturally attract those things which are in the aire about them : thus , we believe hot loafs , onions , apples , dogs and cats &c. draw infection to them , that is , the pestilent vapours which fly in the aire . . but , seeing that emanations strike the aire with a certain kind of agitation ; those things will be easilyest mov'd with this agitation and brought to the body , which are most sollicited by this stroak , that is , those which are most conformable to the particles that sally out . . to which may be added , that such parts , too , will stick faster and easier ; and , when they are united , foment the naturall heat of the body ; which causes this motion : thence , we see that poysons are more easily suck'd out of infected bodies , by other dry'd poys'nous things ; but , best of all , by those very bodies to whom the poyson to be suck'd out is proper . . but , when the parts returning are any way viscous , little light heterogeniall bodies stick to them , too , by reason of their gluyness , and return with them ; as may be seen in electricall bodies , which little straws and dust fly to : and sometimes they rebound again , with a kind of impetus or vehemency ; whence appears , that the steams of such like bodies are very spirited , and start out with certain impetuosities . . out of these things , it appears , that there is , in a manner , a double nature of every mix'd body ; one , as it were , perfect and fit to be evaporated ; another , as it were , imperfect and wanting more concoction ; which two must , of necessity , be oppos'd to one another , by the differences of more and lesse . . now , if we suppose a body so compos'd in its own nature , as to be plac'd between two fountains , as it were , of such steams ; it must , of necessity , attain such a disposition , that , on one side , 't will be apt to receive the one's emanations , on the other , the other 's , and to eject them , again , by the contrary sides . . it will , therefore , have contrary vertues in its extremities ; but , in the middle , an indifferency , at least , in comparison to the ends. . again , its emanations will be carry'd ( against the course of other bodies , which return to their own fountains ) still directly on towards their opposite fountain : and the body , too , if it hang so freely that it may more easily follow its emanations then leave them , will it self be carry'd along with its emanations . . but , if it cannot bear them company , and yet be plac'd obliquely to the fountain , and at liberty to turn it self ; with the same force 't will turn it self to the fountain . . moreover , as the fountain acts upon it , so this body it self will act upon another body of the same kind ; but more faintly . . wherefore , since we find by experience , that a loadstone receives vertue from the earth , as we have explicated it ; and suffers and acts thus from the earth and upon iron , respectively ; and besides , the searchers into its nature declare , that all the rest of its wonderfull motions depend on these : the reason of magneticall attraction is evident , out of what has been said . lesson xii . of the generation of more compounded bodies , and plants . . . 't is plain , out of what has been explicated above , that , not only the elements are blended together to compound a singly-mix'd body ; but also many mix'd bodies are united into one more-compounded body : for , since , by the power of their gravity , moist bodies ( which we call waters ) run down from higher to lower places , and , by their running , presse the bodies they meet , loos'ning partly their little particles in passing by , and partly tearing them off along with them ; the water becomes thickned and full of dregs , with many minutest bodies of divers natures . . this water if it rest in any cavity of the earth , those little bodies sink down in it ; and , whether by heat evaporating the humid parts of the water , or by cold binding them together , they coagulate , by their clamminesse , into one body appearing homogeneous through the littlenesse of its parts : which , being imperceptible , are so equally mix'd in every the least sensible bulk , that they shew every where throughout the same uniforme nature . and , this is the most simple generation of demix'd bodies . . and these bodies , by the fresh accesse of more water , are increas'd ; more of the like matter being added to them by approximation or juxtaposition , as they term it in the schools . . but , if some such thing happen to coagulate , after the fore-said manner , in some concavity not far from the superficies of the earth ; of so tender a substance and with so much heat , that it should ferment within it self : it must , of necessity , suck into its very body any moisture about it , and dilate and concoct it . . wherefore , such a body must needs be increas'd , out of a certain intrinsecall vertue , and with a kind of equality in all its parts , after that manner as they call by intrasumption or receiving in : and so tartufoli , potatoes , &c. grow under ground , without shooting any part of themselves above the earth . . but , if the heat overcome , and be able , by increasing it , to thrust out into the aire , too , some little particles of this body ; which must be of the more subtile ones , that is , the best mix'd of hot and moist : this body will have heterogeniall parts , growing together and subservient to one another ; and becomes a manifest plant , having a root within the earth , and a blade or a stalk above ground . lesson xiii . of the more universall parts of plants . . 't is evident , again , that a plant , being expos'd to the sun and wind , becomes harder and dryer , at least , as to its exteriour parts : whence , it comes to passe , that the moisture drawn up out of the root , either by the power of the sun or its own naturall heat , more and gentlyer irrigates and waters its inward parts . . whence proceeds , commonly , a threefold difference in the substance of a plant : for , the outermost part is hard and call'd the bark ; the innermost is soft , as being that which is last dry'd , and is call'd the marrow or pith ; lastly , the middle is the very substance of the plant. . but , when moisture flows in greater abundance out of the root , then can be rais'd up perpendicularly , which is the hardest course of all ; it breaks out at the sides , splitting the bark of the plant , and makes it self a kind of new trunk of the same nature with the former , which we call a bough , or branch . . but , since the plant receiv's a heat ' variously temper'd with moisture , by the sun : 't is plain , when the moisture is best digested , it must necessarily break out into certain buttons or nuts ; which are concocted by degrees and , from their originall hardnesse , grow softer by the flowing in of more subtile moisture , and participate in another degree , the same differences which are in the stock , to wit , a skin , flesh , as it were , and marrow . . only , because some parts of the juyce are too earthy and , therefore , grow hard ; these commonly coagulate between the flesh and the marrow , the sun drawing out their moisture to the exteriour parts . . these buttons , being found in the more perfect plants , use to be call'd fruits ; and that which has the place of the marrow in them is the seed of the tree . . it appears , again , that , since the temperaments of heat and moisture are varied without end ; there must be , too , infinite other things , as it were , accidentall to plants , besides what we have mentioned . . whence , we see upon some berries , upon others thorns , upon some ioynts , upon others other things growing ; according to the divers natures of the particulars that concurre to the breeding them . . leafs are , universally , common to almost all ; and are nothing but little distinct sprigs , the distances between which are fill'd up & distended with the same-natur'd moisture : for , 't is evident , the substance of wood and almost of every plant consists of certain thrids , as it were , compacted together ; as appears plainly , in the rending them asunder . moreover , if , before they stick well together , a more abundant moisture flows in ; it distends these fibres , and , while the leafs are yet streightned and shut up , makes them enwrap one another as it were , cylindrically , like a bark . . when they peep into the aire , by little and little , the fibres grow stiffe and streight and stretched farther out , and the leaf unfolds it self ; becoming , according to the order of the fibres , broader one way , longer in the middle , and , as it declines from the middle , the figure still abates in longitude : they are split , where the fibres do not joyn together : to conclude , from them and the moisture which connects them , the leafs receive their figure . . it appears , again , that flowers are a kind of leafs ; but of the more spirited and oyly parts : therefore , they are light , odoriferous , and short-liv'd , and , in trees , they are the forewarners of the fruit. lesson xiv . of the accidents of plants . . out of the figure of the parts , the figure of the whole plant is fitted and proportion'd . the trunk , which is the principall part , most commonly grows up like a cylinder , or rather like a cone , because upwards still it grows smaller , and abates in latitude . . when it deviates from this figure , the reason may be easily collected out of the figure of the root or seed . those which have a weak stock or trunk do not grow erect , but either run upon the ground , or else are rais'd up and sustain'd by others , and get a spirall figure , like the winding about a cylinder . . for , the naturall motion of plants being upwards , by force of the heat and sting out of the earth ; and the trunk , by reason of its weaknesse , not being able to bear much : it bows towards the earth , and strives to rise again as much as 't is able ; & so imitates the figure of a serpent creeping . but , if the stemme cling to some prop that may help it upwards ; it elevates it self , not directly , or in a straight line , but , as well as it can , winding round about the sides on 't . . again ; because we see ther 's both a kind of annuall and diurnall , as it were , flux and reflux of heat from the sun : some plants are but of a day's life ; as certain flowers , which , the same day , blow and wither . . very many last not above a year ; and then are repair'd again , either by shedding their seed , or by the reviving of their fountain , the root ; or else by the very temperature of the soil . others of a more constant substance , do not only sustain themselves , but increase for many years . others , again , even out-last ages . . all have the same reason of their life and death : their life and increase consists in a due proportion of moisture with heat ; where this fails , they faint and consume away . . a plant dies , either because the sun , sucking the moisture out of the upper parts of the earth , has not left wherewith to moisten the root : or , because too much moisture overflowing the root without a proportionable heat , has too much dissolv'd and diffus'd the vertue of it ; so that the sun supervening has extracted its very radicall heat , before it could increase and supply it self : . or else , because , by little and little , earthy and feculent parts , cleaving to the root , have obstructed the passage of the moysture to the inward parts of it : and this way of death , because it follows out of the very action of life , seems more properly to bear the denomination of old age and a naturall way to death . . out of the same principles , 't is apparent , why severall parts of the same plant produce such contrary effects : for , since , in the nourishing of the plant there is a kind of perpetuall streining and separating of the parts of the aliment , most of the parts of the same nature must , of necessity , run together to one and the same place and part : whence , the severall parts of the plant are compos'd of heterogeniall particles of the nutritive moisture ; yet , more or lesse sated , too , with the temper and seasoning imbib'd in the root : thus , therefore , 't is consonant to reason , that a plant should be compos'd of contraries and things that have contrary vertues . . the same way we come to understand the sympathy and antipathy which is found in divers plants : for , since 't is certain that every plant , to its measure , has a certain orbe of vapours always encompassing it , ( as is evident , in some , by the fmell issuing from them , ) and some plants must needs consist of contrary natures ; if the weaker happen to be planted within the sphear of the stronger , that corrupts and kills it with the stroaks of its vapours which besiege it ; but , if the stronger be of a nature that is a friend to it , by the same stroaks it grows more lively and fruitfuller . lesson xv. of the generation and augmentation of animals . . and because , the more fervent the heat is and the moisture more figurable , ( that is , in a certain proportion , neither resisting division , and yet easily consistent ) the plant is divided into so many the more members and joynts : 't is evident , if there be so much heat as to exhale fumes out of the moisture , and make it actually fluid , the little branches , through which it flows and wherein 't is contain'd , will of necessity become hollow . and since , by force of the heat , the moisture is refin'd into watry and oyly parts , the earthy remaining still below : it comes to passe that there are found three , as it were , severall , but subordinate , fountains of moisture in the same plant ; and , from every one of these their branches , and , in them , their own proper moistures are deriv'd . . among which , those that savour of water are the more remote , and more fit to form the exteriour parts of the plant ; and the enclosed humour is more apt for those effects which are perform'd by rarefaction and condensation . . those which savour of oyle are fitter for augmentation ; as being of a kind of middle nature , and conformable to all the parts . lastly , the earthy , for the conservation of the whole plant in a due temperament , by the mixture of heat ; which the more solid parts are more susceptible of and longer hold . . again , because the watry parts are very thin and , as it were , in a middle between water and aire , in those long and narrow channells ; 't is clear that they are both extremely passive of every impression from without , and transmit it to their fountain or head . . and , because their head has a connection with the principall fountain ; for the most part , the same passion will passe on even to that : in which , the heat being very acute and spritely , and , consequently , capable of sudden motion ; a change in the plant , proportionable to its nature , will necessarily follow the impression made upon it . . this plant , therefore , will have these two qualities : to be stir'd up , as it were , and irritated with all occurrences from without ; and this very principle or head thus irritated , will have power to move any part of the plant out of its present site into another , according to the manner and measure of the irritation . . which two , making up that whereby we distinguish living creatures from such as have no life , namely this , that , upon all occurrences from without , they can move themselves ; 't is evident , that the name of an animal or living creature agrees to this plant : we have , therefore , an animal , consisting of three principles , a heart , a liver and brain ; watred with three rivers , of the vitall and animal spirits and the bloud ; by the three various channels of the arteries , veins and nerves . . but , because all things are increas'd by the same things whereof they are made ; and all mix'd bodies are compos'd of the elements ; 't is clear , that animals may be increas'd by all bodies , so that they be furnisht with fit instruments to make the necessary transmutations . . but , some bodies are of a harder transmutation , others of an easier : wherefore , bodies ought to be chosen fit for the food of the animal ; and those that are chosen should again be resolv'd into parts , that the best may be taken and the worse rejected ; and this , as oft as is necessary , that is , till such are chosen as , by mere concoction and mixing with the humours of the animal , may be reduc'd into a substance like it . now , whilst the fibres are distended with this moisture , both they are strengthned by it and the spaces between them are fill'd up : and , thus , the animal becomes bigger . . and , because this is brought about by concoction ; those bodies which have not yet arriv'd to the degree of the animal , must needs be the most connaturall aliment . lesson xvi . of the motion of the heart , and some consequents of it . . again , because the heart has heat and moisture in it , and moisture boyls with heat , and is turn'd into fumes ; 't is manifest , the same moisture does not remain constantly in the heart , but , being resolv'd by the heat , is cast out by the motion of the heart , swagging down and shutting it self with its own weight , till 't is open'd again and swell'd with other moisture flowing into it . . there is , therefore , a continuall flux of moisture through the heart ; which , heated in it and then cast out to be dispers'd through the animal , conserv's it in a due temperament of heat . . out of what has been said , may be understood , what a disease and the cure of it is : for , when any part is indispos'd , so that unwholesome vapours fume out of it , they , mix'd with the bloud , overrun and discompose , as much as they can , the whole body and the very heart it self . . and , according as these vapours do more frequently rise to such a bulk , that they are able vehemently to assail the whole animal ; so much the frequenter are the fits of the disease . and thus , some are continuall , and others have intermissions ; some every other day , some tertians , some quotidians , &c. . and the true nature and method of curing is , to seek out the part originally ill-affected , and apply remedies to that . . thus , too , it appears , how physick expells one certain determinate humour out of the whole body : for a drug , &c. being concocted in the ventricle , which has a power of dissolving and rendring fluid a certain humour of the body , its vertue is diffus'd through all the veins by the fore-explicated motion of the heart ; whence , it comes to passe that , being provok'd to stool , that humour rather and more then any others follows out of all the members ; or , if the physick be diaphoreticall , that will sweat out more then any of the rest . . lastly , 't is clear , since an animal is a plant ; by the highest concoction , a seed or compendium of its nature may be framed in it as well as in plants : which , duly ejected into a congruous ambient body , may spring up into a new animal . . now , this seed coagulates first into a heart , then into a brain , and at length into a liver : out of every one of which their own proper little channels spring ; as is observ'd by those that pry artificially into these things . lesson xvii . of the progressive motion of animals . . out of what has been said , it may evidently be concluded that , since the heart is mov'd naturally and , by its motion , presses out a fumy humour , which they use to call the spirit , into the channels connected with it self and into the bodies joyn'd to it : and the flesh is fibrous , viz. certain parts constipated together of a world of minutest fibres sticking to one another : and since , if a connaturall moisture , especially being warm , get into such a body , it makes it swell and , of thin , become thicker , of long , shorter : it comes to passe that the members , whether consisting of such fibres or knit together by them , attain some kind of locall motion , by that irrigation from the heart . . again , the channels , especially if they are extremely little , will swell , too , and become shorter . . since , therefore , 't is apparent , that there flow abundance of spirits from the heart to the brain ; and again , that , from the brain through the whole body , mostsubtilly-hollow nerves are extended to all the members , and lose themselves by their dispersion , as it were , in the muscles : 't is plain , the muscles will swell with these spirits , as oft as the heart overflows ; and consequently , become shorter , and the parts adhering to them be drawn backwards to the head of the muscles ; and , which clearly follows , all the extremities of the body be mov'd , from the motion of the heart , according to what is convenient to its nature . . it follows , too , how certain other members , which have no nerves but only fibres , have motions of their own ; which consist almost in nothing else but in contraction and dilatation : for , the fibres being made shorter by their irrigation , they draw the body with them into that figure which follows out of their contraction ; which , when the fibres are transvers'd , is dilatation , when other ways set , contraction . . again , hence appears how the progressive motion of an animal is effected : for , an animal which is mov'd by walking , whilst it stands still , has the centre of its gravity set directly to the centre ; but , when it sets a foot any way , it inclines the centre of its gravity , and consequently its whole body , that way ; till , transferring the other foot , it sets it down too : and this often repeated is walking . . but , one that leaps , when he has contracted the superiour or fore-parts to the inferiour or hinder-parts ; suddenly pouring out spirits through convenient nerves , he thrusts the fore-parts forwards , with such a force that the hinder-parts follow them . . something like this is the creeping of feetlesse creatures : for , fixing their breast or some other part , they bow their back-bone or that which serv's in stead of it , and so draw the hinder to the fore-parts ; then , fixing some of their hinder-parts to the earth , they advance their fore-parts , by straightning again their back . . swimming is made out of leaping : for , it being effected by the instrument's first being crook'ned and then straightned again ; by the resisting water the body is pusht forward : and , the same happens in flying . . now , the body being heavier then the medium in a certain proportion , and consequently , obliged to spend a certain time in descending ; and the adventitious motion making the medium strain with more vehemence against that motion of the body downwards , or according to the centre of its gravity : 't is plain , such a body will not sink . lesson xviii . of the five senses of animals . . out of what has been said , it appears , that there are certain channels spread through the whole body of an animal , full of a kind of aiery humour ; and that they are long and narrow : whence , the least impression made in any extremity of the body must needs , in a moment , run to their fountain , the brain ; and , thence descend to the heart . these channels , therefore , being any way obstructed , the animal is sensible of nothing without . . and , since bodies that make impression , either do it by their immediate selves , or else by the mediation of some other body ; and , those that act by their immediate selves , either do it in their proper bulk , or broken into parts , or by naturall emissions ; and those bodies , by the mediation whereof universally one body acts upon another , are either aire , or fire , or light which we see every body bandies against another : it follows , that an animal , if it be perfect , may be affected these five ways by the things about it . . and , because 't is evident that these five ways are distinct ; the animal , too , it self will have five distinct dispositions , by which it will be apt to receive these five impressions ; to chuse the things that are congruous and refuse those that are noxious , both in its food and other things belonging to its conservation . . again , because these impressions are different ; 't is fit the organs that are to receive them be plac'd in severall parts of the animal : animals , therefore , have five senses . . 't is apparent , too , that the senses are nothing but certain different degrees of touches : for , the parts of the same body must needs make only a more subtile stroak , of the same nature with the stroak of the whole . . and , hence , we distinguish the differences of tasts ; so , as , that one pricks , another cutt's , another brushes , another smooth's : the differences of smels , too , are a-kin to tasts . . but , the differences of sounds are the same with those of motions ; distinguisht by swiftnesse and slownesse , by bignesse and smalnesse , lastly , 't is evident , that fire or light make stroaks too , by its activity upon other bodies . . it appears , farther , of what nature the senses must be , and where situated . for , the touch , being to receive the excesse of those qualities whereof the body of the animal consists , requires nothing but a middling kind of moisture , or the naturall quality of that vapour which fills the channels ; and therefore , like them , 't is diffus'd through the whole body . . the tast , because it requires a moistnesse which may dissolve the minutest parts , needs an abundance of moisture , and a site where the food may be dissected . the smell , by which aire chiefly enters into the body , requires a site and organ where the vapours may stick , that , being constipated together , they may act the more powerfully . . the hearing and sight require a situation near the brain ; in an eminent place , where motion and light may come to them more pure ; and organs , which may multiply light by refraction and motion by reflection . . nor is it lesse evident , that the sensation is perfected in that part of the organ , where chiefly resides that vertue for which the sense was made ; that is , to transferre to the brain the action of a body without : if the black of the eye , the hammer of the eare , the pulp of the nose doe this ; the sensation also must be plac'd in them . . it appears , too , why the senses are believ'd to consist in a kind of spirituality and abstraction from matter : for , since they are ordain'd by nature , only that the animal may be mov'd ; the stroak of sensible things is so thin and subtile , that it changes not the quality of the organ sensibly , and , therefore , 't is not believ'd to be materiall . . and , hence , too , the sensible object is commonly believ'd to be in the sense , not as something of the same nature or contrary to it , but purely as another thing ; by which mistake , sensation is thought to be a kind of knowledge . lesson xix . of the objects of the senses . . lastly , it appears , wherein consists the being objects of sense : for , touchable things , 't is plain , are the first qualities , or those which are immediately deriv'd from them : tastable things , conformable to nature , are sweets ; and must necessarily consist , as the nature it self does , in a moderate heat and moisture , or , of the degree proper to the animal . . from this temper , other savours incline , too much , towards cold and heat , or moisture and drynesse : as salt , sharp and bitter things tast too much of heat ; restringent , crabbed , of cold ; sour , bitter and sharp , of drynesse ; insipid , of moisture . proportion'd to this is the account of smells . . sounding things are dry and trembling , which are easily wav'd up and down : but , soft things hinder sound . . since colours strike the eye , their nature must consist in a vertue to reflect light ; that is , in a density & constipation of parts , and in having a many-corner'd figure : and these commonly favour of cold and drynesse ; and their opposites , of moisture and heat . . lastly , light it self ( and dilated flame , if wee 'l suppose it repell'd from the object to the eyes , must necessarily doe the same as light ) will represent the figure of a thing by intershadow'd stroaks upon the organ , and strike , more or lesse , according to the nature of that which reflects it : if it passe through a triangular glasse , it will receive and carry to the eye the same varieties , that is , differences of colours . . but , that light , too , does those things which are proper to fire , ( viz. to dry , to burn , to be reflected , refracted , collected , dispers'd , produced and extinguisht , ) is so clear , that it cannot be doubted but light is fire . . nor imports it against this , that it seems to be mov'd in an instant , that it fills the whole aire , that it penetrates solid bodies , as glasse , &c. for , these things seem so only , through the defect of our senses ; which perceive not its motion , nor those little spaces by which the aire is separated from the light , nor the pores of those bodies through which it passes . lesson xx. of knovvledge and memory . . farther , it appears , that these motions , when they strike against the destin'd part of the brain , in which knowledge is produc'd ; though it be fatty and clammy , according to the nature of the brain , yet are they repell'd from it , because frequent new impulses charge upon the same point . . those little bodies , therefore , retreat thence , carrying away with them some little particle of the brain which sticks to them ; and wander up and down in the ventricles of the brain , till they rest upon the bottome or stick to the sides . . whence , being rub'd off , as it were with a brush , by the motion of the spirits , when there 's occasion ; they swimme again , and are brought back to that part which is the fountain of knowledge . . the first stroak produces knowledge ; the later , actuall memory ; which , if it be made by design , is call'd remembrance . . again ; since motion requires that the nerves be well fill'd with spirits , and that the extrinsecall parts be strong ; but sensation needs only a clam and clear disposition of the humour contain'd in those nerves : 't is plain , both that there may be sensation without motion , and motion without sensation . . it appears , too , why the memory is set a work by the similitude , as also by the connection of objects : for , since , in a liquid body , things that are alike naturally gather together , and are apt to stick to one another ; and , since those things which enter together and at once must necessarily attain a kind of connection , which is easily preserv'd in the clammy nature of the brain ; when , by any means , they are brought again to the fountain of sensation , they must needs meet there together , and in a kind of order . . but , since contraries use to enter together into the internall sense , and make one another more taken notice of ; 't is plain , if hunger provokes the animal , 't will remember meat , if thirst , drink , if seed , the female . whence , it appears , that passion and will stir up the memory : as also other causes , too , which , by pouring in spirits , sweep or brush , as it were , the brain ; and for that these causes do this by accident , they are all comprehended under the name of chance . . it appears , again , that they , whose brain is of a thin and hot constitution , easily apprehend , conjecture happily , opine rashly and changeably : they , whose disposition is more dry and thin , have a good memory and rememberance too , but opine lightly and changeably . . they that have a temperate brain , have the best judgement : since , they look upon many things , before they establish their opinion ; and , for the same reason , they are not changeable . . lastly , since , by the stroaks of objects , some litle particle is still taken off and carry'd away from the brain : when the same returns again , it must needs appear that we have been sensible of that before . lesson xxi . of sleep and dreams . . it appears farther , that , since the nerves must needs be distant from that part of the brain wherein sensation is produc'd ; it may fall out , that , the motion by the nerves being obstructed , there may yet a motion proceed , from some part of the brain to the knowing part : and then , some things will appear to the animal to be , as if it had receiv'd them by its senses , when yet it did not receive them . . this stopping of the senses is called sleep ; and such apparitions , dreams : an animal , therefore , will sleep and dream sometimes . . but , because there 's no necessity , that all the senses or nerves must be stop'd at once ; 't will happen , that an animal may partly sleep and partly wake : whence , it comes to passe that , the nerves of the tongue being left unstop'd , some talk in their dreams ; and , if the nerves for hearing , too , be unstop'd , that they answer to those that speak to them ; or , if there be no obstruction towards the marrow in the back-bone , they walk , too , and use their hands . . when , therefore , some of the senses are at liberty , dreams may be provok'd by them : another way , by some naturall disposition , which affects the heart , and makes a motion in the brain conformable to that impression : or , lastly , by much precedent thinking , objects may be stirr'd up and down , too , in ones sleep . . but , a man being in a manner quiet in his sleep , he happens sometimes to judge more truly of things he sees , in his sleep , then when awake : for the soul undisturb'd , of its own nature , more clearly perceiv's the force of the objects playing up and down before it , to discover truth ; and unperceiv'dly orders them : hence , it comes to passe , that , sometimes , we discern , in our sleep , future or absent things , which we could not find out nor pierce into , by consideration , or discourse , when we were awake . . and , the same may be the case of fools , mad and melancholy persons ; though 't is very rare and to be esteem'd prodigious , and they have a great many falsities mixt withall : whence , neither are these apparitions to be confided in ; nor is it possible there should be any art of divination by dreams . lesson xxii . of passions and the expression of them . . farther , 't is deducible , that , since impressions made in the brain are convey'd , by a short and open way , to the heart ; they must , necessarily have an effect , too , in the heart , conformable to the natures of both . . since , therefore , the heart redounds with hot spirits : as we see a little drop of red wine , dropd into water , diffuses it self into the water and changes it , according to its nature ; so , the impression of these little bodies will have the like effect upon the fumes of the heart . . hence , again , it proceeds , that the motion of the heart , through these , becomes sometimes freer and better , sometimes worse ; and that these very qualities passe into the pulse , whence , according to the variety of passions , the pulse varies . . again , passions must needs differ by dilatation and constriction : for , by a conformable object , the spirits of the heart are made more rare , whence , the heart more freely enjoys its motion ; by things disagreeable to nature , the spirits become more crasse and heavy , and the heart is , as it were , oppress'd . . again ; since an absent object does not equally affect , with a present one ; these motions will be more remisse in its absence then in its presence : whence , we deduce four differences of passions ; ioy and grief , for a present good or evil ; hope and fear , for them absent . . anger is , in a manner , mixt of a present evil and future good : and , 't is the most violent of all the passions ; because , so mething that 's contrary to it falling into an abundance of hot bloud , produces a most swift effect ; just as when something moist and cold falls into molten metall . . again , because the spirits , flowing at that time out of the heart to the brain , retain that nature they had receiv'd in the heart ; in the brain it self they gather to them those phantasms that are conformable to them : whence , the animal must , of necessity , be much fixt upon that thought , and not easily admit any other then such as are conformable to its passion . . and , because the heart is joyn'd to the pericardium , and the pericardium to the diaphragm ; and the diaphragm is furnisht with an eminent nerve , and is moveable within it self : it comes to passe , that every motion of the heart flow's , by the diaphragm , into the neighbouring parts of the body , and all the motions of them all return again , by its nerve , to the brain ; and , so , beget a sense of that grief or pleasure which the heart is affected with . whence , too , without any externall sensation , but by thinking only , an animal may be delighted and incourag'd to action . . again , because , by repeating either the stroaks of objects or very thoughts , there grows a great multitude of phantasms of the same thing , in the brain ; and , in like manner , the heart often agitated by such like causes in a certain motion , gets an aptitude to be easily mov'd so : there grows , both in the brain and in the heart , a certain constancy and facility of knowing and doing ; in which consists the notion of intellectuall and morall habits , as far as they are grounded in the body . . lastly , since , by the motion of the diaphragm , the breathing is alter'd ; and breathing , express'd out of a hollow place through a narrow passage , is apt to yield a voice , by reason of the multiplication of its processions , occasion'd by the reflection of the cavity : it comes to passe , that the voice of animals is altered by the variety of their passions ; and so , in grief , they expresse one voice , another in hope , another in joy . lesson xxiii . of the communicating affections to others . . farther , it appears , that , since , all sensations ( whether of those things which affect the body from without , or those we are sensible of because one part of the body affects another , ) are produc'd in a certain site to the organ of sensation , that is , in a right or the naturall line of motion , from the entries of the nerves to the place of sensation : it follows , that , when we think of the same things , they must be in the very same site and posture ; whence , it comes to passe , that , in dreams , and in distraction of mind we seem to see the very things themselves before us . . 't is apparent , therefore , they are in a fit situation for this , viz. to be press'd , by the motion made by the heart , into the same nerves : whence it follows , that , by the thinking on any object , the nerves are just so mov'd as when the senses convey it ; and consequently , the same action is apt to follow . . and , thus we see , laughing and gaping , &c. proceed from seeing others doe so ; as love and hatred from hear-say . . hence , it comes to passe , that blearey'dnesse and other distorsions of the members are often deriv'd from beholding others : that contagious diseases , too , ( for which some disposition in the body prepares the way ) are attracted and , as it were , suck'd in , by fear : and , that other diseases , which the retraction of a humour to some certain parts produces , are introduc'd by mere sight or imagination only . . again , because the members of the body are connected , and the exteriour depend upon the interiour ; these operations cannot be produc'd , but that , byconnection , the exteriour members must some way be chang'd : and thus , we see , all the passions shew themselves in the countenance and actions of animals ; upon which depends the principles of physiognomy . . again ; because usuall motions render the organs apt for such motions : it comes to passe , that , in generation , the like dispositions are oft transfer'd to the issue , and the off-spring becomes like the parent , both in its naturall operations and those which depend upon sensation ; nay , even in some triviall things , too , as in warts , in hookednesse of nose , and the like . . moreover , since the issue in the womb derives its nourishment from the mother , 't is no wonder if the desires of the mother , at that time , passe into the issue : as , if they long for wine or whatever other food or pleasure , that the issue should suck in such a disposition as to be obnoxious to the same things all their lives . . again , since such longings fix a vehement resemblance of the things in the fancy ; and terrour , too , or any violent passion does the same ; and that image is made by motion : 't is no wonder that the spirits of the mother tremble with the same motion , even as far as to the issue it self ; and that , as light with its stroak , paints in a glasse the reflected image of a body , so this image should , in the little tender body of an infant , and where-ever it finds matter apt to preserve it , leave an image fixt in the flesh , as it were a mark of that desire . . and , because , too , the infant is never more tender then at the first commixtion of the father and mother's seeds , and women , in the conjugall act , especially some , are very passive : 't is no wonder , if a violent apprehension of their's , in that conjuncture , often changes the complexion of the issue ; the female seed receiving a kind of proper stamp , from the image which possesses the mother's fancy . lesson xxiv . of the seeming-rationall actions of animals . . 't is plain , again , that animals must , of necessity , operate seeming-reasonably , or like reason : for , since the work of nature is the work of that reason which fram'd nature ; the effects of nature must needs be the works of the same reason , and resemble the manner of reason's working . . again ; some of their operations must needs exceed those which reason works in us : for , since they spring from a reason which transcends ours , 't is but consequentiall , that they should transcend the effects of our reason ; as appears in generation , which we understand not how 't is done , even when we doe it ; as neither could a man tell the houres of the day as a clock does , which yet is it self but a work of our reason . . it appears , too , whence proceed the antipathies and sympathies of animals : viz. partly , out of the naturall disposition of contrary qualities , as in plants : partly , out of an apprehension of evil joyn'd with the object ; which sometimes takes its rise in the parents , and is transmitted to the issue , out of the disposition of the parents body . . farther , the vertuous actions of animals , as those of ove of glory , gratitude , generosity , &c. are nothing but such materiall impetuosities ; which , because we feel in our selves joyn'd with vertue , we , therefore , believe to be just so , too , in animals . . lastly , their concatenated and orderly-proceeding actions are the effects , partly , of fore-going actions , partly , of the disposition of the circumstant bodies ; as they may find by experience , whoever have the leisure to observe a dunghill hen : the admiration of which actions ought not to stop at the animals , but at their maker ; who has fram'd such a concatenation , out of which the effect follows after so many causes . . and , thus much may suffice about animals , in common . man three things raise above the crowd : in his internall sense , that he can order , and rummige for , and own , & use the instruments of knowledge : in his tongue and voice , that they do not purely expresse his passion , but even his mind , too : in his body , that he has hands , an instrument not fitted to any one determinate operation , but destin'd to a kind of universality of acting . but , in these three , there 's nothing requires a comment . peripateticall institutions . third book . containing those things , which concern the world and its greater parts . lesson i. of the limitation , unity , and composition of the world. . the world we call , the collection of all existent bodies . that this is not infinite , 't is evident : for , if any longitude be infinite , that very notion imports that it has infinite parts equall to one another , ( paces , suppose , or feet ) ; and consequently , from an assigned point in that line , some one foot will be , by infinite others , distant ; and so a term assign'd , and limits fix'd at both ends , to a line which is call'd infinite . . if you answer , some one foot is infinite intermediate ones distant from an assign'd point , but that foot cannot be assign'd ; as some one horse is necessary to ride on , yet no determinate one : 't is reply'd , indetermination and infinity are qualifications or manners of a thing in potentiâ or possibilitie : and so a horse is undetermin'd whilst he is yet but necessary , that is , in possibility , not in act . . nor makes it against this , that there are infinite objects in the understanding of the intelligences : for , admit there were , we are not sure they are there actually distinct , and not after the manner of one . . you 'l say , suppose quantity to exist as great as 't is possible , and 't will be infinite : 't is no contradiction , therefore , to suppose it infinite . 't is answer'd , that , since , supposing any quantity , how big soever , yet one may alwaies suppose a bigger ; there is no quantity so big as may exist : whence , this is an implicatory proposition , that is , such as couches contradiction in it self ; as taking the manner of possibility to be the manner of act . . again , 't is evident , there 's but one world : for , since there 's no space , by which two worlds could be separated one from the other ; and quantitative bodies joyn'd together , even by that very conjunction , are one ; all quantity whatever must , of necessity , by continuednesse , conspire into one bulk . . again , 't is collected , that the world is not compos'd only of minute bodies , by nature indivisible : for , since an extrinsecall denomination is nothing , but the intrinsecall natures of the things out of which it rises ; and , if there were only indivisibles in the world , all the intrinsecalls would remain the same ; since the same things alwaies afford the same denomination , 't would be impossible any thing should be chang'd . . and , hence it follows , that there is still some liquid substance , where-ever there 's any locall mutation : and therefore in heaven it self , the sphears cannot be so contiguous that there intervenes not some liquid and divisible substance between them . . since , therefore , a whole , after 't is divided , is no longer what it was ; every divisible substance , in that very respect , is mortall . wherefore , every moveable body must needs be either corruptible it self , or joyn'd to something that is corruptible . lesson ii. of the mortality and kinds of those things that are in the world. . t is infer'd , that all corporeall nature whereever is corruptible ; since all participate the same nature of quantity : whose differences being rare and dense , and , out of their permixtion , the elements and all mixt things being deriv'd , the differences of all quantitative things , that is , bodies , must needs be proportion'd to these we see amongst us ; that is , there may be elements or mixt things differing , indeed , in temperament , but the same and entirely agreeing in the common notions . . again , since the differences of mixt things , vegetables and animals , both from one another and among themselves , are condivided by the opposition of contradiction ; that is , by this not being so much as that ; as , mixt bodies are either vegetable or not vegetable , and vegetables are sensible or not sensible , &c. though we cannot tell whether all our kinds may be found in the other parts of the world ; yet , certain it is , that no other kinds can be found , which may not be reduc'd to these amongst us . . 't is objected , since the notion of a body is , to be moveable ; bodies , to which a simple motion is naturall , must be simple : now , we find three simple motions in nature , upwards , downwards and circular : the former two of these oppose one another , and consequently , both they and the bodies , whose they are , destroy one another and are corruptible ; circular motion , therefore , because it has no opposite , must be incorruptible , and so the heavens , too , to which this motion is proper . 't is answer'd , since a body is a mover mov'd ; and to be a mover is a nobler notion then to be mov'd ; the differences of bodies are rather to be deduc'd from that of being movers , then from this , that they are moveable . . again , 't is false , that the subjects of simple motions must be simple bodies : for , both all mix'd things are carry'd upwards and downwards , and two elements are assign'd to either of these motions ; and , which is most considerable , these motions agree to these bodies , by accident , not out of their naturall disposition . 't is false , too , that the third , viz. circular , is a simple motion : for , aristotle himself acknowledges it to be compounded of thrusting and drawing ; and 't is manifestly carry'd on according to two perpendiculars at once , and at least four times reflected , and has a great difformity in the proportion of its carriage : whence , it appears , if we were to judge from the nature of their motions , the heavens must needs be no simple but a most compounded body . . 't is objected , again , there would have appear'd , in so long time , some change in the heavens , if they were corruptible . 't is answer'd , there 's no necessity of that ; as 't is not credible that , if one were in heaven , he would discern the changes we suffer : but , again , many things have appear'd , as more at large shall be shew'd hereafter . moreover , light is concluded to be the same with fire ; and that our very eyes witnesse to be spread every where over the visible world : but , where there is any one element , there , aristotle acknowledges the rest , too ; and indeed , with the same eyes , we discern an opake body reflecting the light . . 't is objected , animals cannot live in the moon ; not men , particularly , because , in it , there is not a variety of earth and waters , nor rains , nor clouds : adde to this , a most vehement heat ; the sun shining continually upon the same part for fifteen whole days together , and never receding , in latitude , above ten degrees from the part illuminated . . 't is answer'd , if there be a kind of grosser aire , as 't is observ'd , there will , of necessity , be water : for these grosse vapours are made out of earth , and have the nature of water before , though perhaps the clouds are not so big as to be taken notice of . besides , the almains have observ'd something like a vast cloud in the moon . the extreme heat is moderated , by the height of the mountains , the lownesse of the vallies , the abundance of water and woods : as we see by experience under the aequator , from which the sun is at farthest about twenty three degrees distant ; and , but about ten only for half the year , from the middle between the aequator and the tropick ; yet this hinders not but those are most happy regions . lesson iii. of the parts of the planetary world , and especially those of the earth . . the greatest part of the world , which we have some kind of knowledge of , consists of the sun and six great bodies illuminated by it ; and some lesser ones , which are , in a manner , members cut off from the greater . . the bigger bodies are counted by astronomers , saturn , iupiter , mars , the earth , mercury , venus : which , 't is certain , ( of the rest by evident experiments , of mars and saturn by their parity to the rest ) are opake bodies , illuminated by the sun. . mercury is believ'd to have appear'd like a spot under the sun. venus appears horned like the moon . iupiter ; suffers from the stars accompanying him and they , reciprocally , from him . the sun alone shines of it self . . moreover , since light is fire , the fountain of light is the fountain of fire , too . the sun , therefore , is a vast body , consisting of mountains and plains which belch out fire ; and , as aetna , lipara and hecla are never without flames , and especially the vulcanian mountains of the new world , so , much lesse is the sun. . both the clouds of ashes ( vapour'd out in vast abundance ) and other bodies mix'd with them , which make the spots in the sun ; and the fountains of flames , observ'd , sometimes more fiercely sometimes more remissely , to blaze out , witnesse this to be the nature of the sun. . the whole body , therefore , of the sun , or , at least , as deep as is necessary , must needs consist of some matter resembling to bitumen or sulphur ; and be intended by nature for nothing but an esca and food of flames , serviceable to other bodies . . and , since we have the same actour upon the other six bodies , the effects , too , must needs be analogous upon an analogous matter , as we have already prov'd that of all other bodies must be : amongst these , the earth , by which we are nourisht , is the best known to us . . this , our very senses tell us , is divided into three parts : a solid substance , which we call earth ; a liquid but crasse one , which we call water ; and aninvisible one , which we call aire . . the earth is not a loadstone : first , because it hangs not on any other ; for , the stars of the eighth sphear are at too great a distance , to look for any magneticall action from them : secondly , because that vertue in it which attracts the loadstone , is not diffus'd through the whole body of the earth , but rests only in the bark of it , as it were : thirdly , because , if it were a loadstone , it would joyn to some other body , as the loadstone does to iron ; nor would it be carry'd about in any place or with any motion of its own , but proceed to joyn it self with that other . the parts of the earth are mountains , valleys , caverns , plains . . and , since , we know , fire will make water boil and swell , and dilate whatever other bodies are mixt with the water ; we see , too , that the earth , both within in its bowells , and in its superficies , is furnisht with heat to concoct metals and juyces : as , in our bodies , when the heat abounds with moisture above the just proportion in any part , it breeds warts and wens and blisters ; so , hills and mountains must , of necessity , rise out of the body of this great mother . . this is evidenc'd both by ancient and modern experiments , which tell us of islands cast up in the sea : we hear of cinders belcht out of aetna and vesuvius ; for the most part , falling upon and encreasing the mountains , but sometimes , too , raising fields into mountains : and , hence it is , that mountains , for the most part , ingender metalls and are full of wholesome hearbs , as is generally observ'd . . hollow places , whether upon the superficies of the earth , which we call vallies , or caverns within its bowells , proceed from two proper causes : the sinking and settling of the earth into those places , which the matter for the mountains left vacant ; and the washing away of that matter which , by rains and torrents , is carry'd otherwhere , especially into the sea. thus , the channells of rivers are made ; thus , between vast and very high mountains , the channells of the valleys are deeper : hence , in one place , the earth is hollow'd away , in another rais'd . lesson iv. of the sea , and its accidents . . the parts of water are sea , lakes , pools , rivers , fountains . the sea is but one ; since , all those parts , whereof every one is call'd a sea , communicate among themselves , either openly , or by hidden channells : as , the caspian discharges it self into the euxine ; for , otherwise , t would overflow with the constant tribute of such great rivers . . that the main does not overflow , is because of the amplitude and vastnesse of its surface : whence , it comes to passe , that as much is lick'd up by the sun into clouds and winds , as is pour'd in by so many rivers ; as will be evident to one that shall observe how much the sun , in one day , draws up out of a little plash . . hence proceeds its saltnesse : for , since the salt which flows in out of the rivers makes not them so much as brackish ; neither could they infect the sea , were it not that , the sun sucking up the lighter parts , the salt remains in the rest . . moreover , the salt , which the sun must necessarily make upon the top , out of the concoction of the land-floods which fatten the river-water , does not sink down to the bottom ; both by reason of the motion of the sea continually mingling it together ; as also because , the deeper the water , the salter and heavier it is , unlesse some speciall cause interpose , as perhaps in the mouths of rivers . . from the abundance of salt , the sea gets both density and gravity ; moreover , that it will not extinguish flames very readily ; as also , by a multiply'd reflection of light , to sparkle and flame , as it were , when 't is stirr'd . . the same , too , is no little cause of sea-sicknesse , ( besides the very tossing , which , of it self , is a cause ; as appears in those who are sick with riding in a coach ) ; for , the stomack , being offended with the saltnesse , strives to cast it up ; as appears by that salt humour we oft are sensible of in colds . . hence , too , comes it , that the sea is not frozen ; the mixture of salt hindring the freezing wind 's entrance : for , where the sea is congeal'd , 't is not the sea-water , but the snow falling on it , which makes the sea seem frozen ; as our countrey-men , that go northern voyages , witnesse . yet , others report that , near the shoars , a sharp wind will freez the sea in some , ev'n hotter , countreys . . but , when vast rivers flow into narrow bayes , they must needs overflow into larger seas : whence , of necessity , there must needs be a kind of perpetuall flux of some seas into others ; as , of the euxine into the propontis , of this into the mediterranean , of the mediterranean into the ocean . the reason is , because the lesser sea , with the same quantity of water , is more swell'd and , consequently , has a higher levell of water : again , the power of the sun drinks more out of a larger sea then out of a narrower ; whence , 't is more easily sunk low to receive the adventitious waters . . out of the sea , the sun , like fire out of a boyling pot , extracts continuall vapours ; which , either in rains or winds , it disperses over all the earth : for , all those winds , which we feel cool from the ocean in the summer , though we perceive it not , yet , both their extraction makes us confesse they are moist , and their density and softnesse , savouring a similitude of and derivation from water . . the earth , therefore , heated by the sun , being sprinkled with these , whether in rain or wind , ( for the earth , being once hot , a great while retains it ) dissolves it self into vapours : and so , by little and little , they are rais'd to the higher parts of the earth ; where if they feel the cold of the aire without , or , by any other cause , are coagulated into bigger parts , they become water , and by degrees , break themselves a passage through and flow down upon the lower grounds . lesson v. of fountains , rivers , and lakes . . and , because the causes of evaporations are continuall , fountains , too , continually flow ; which , joyning together , make brooks and rivers , and , when they have watered the whole surface of the earth , restore to the sea the superfluous moisture , to repair again the earth with a new distillation . . let him , that thinks not the rain-water sufficient for this , imagine the mountains , out of their innate heat , are more pory then the rest of the earth , and hollow , as we have said ; wherein there may be receptacles of water : out of which the heat , that is every where mingled , often draws vapours , which it transmits to the top of mountains covered with rocks ; whence , afterwards , water starts , as it were , out of bare rocks . . that this is the generation of fountains , the stones and earth at a fountain-head , all deaw'd like the cover of a boiling pot , are an argument : also , the thinnesse & subtilty of the vapours so rais'd through the earth ; & certain herbs , too , nourisht by such like vapours : by observing all which , the water-finders search for well-springs . . of fountains , the famousest are baths , that is , hot ones . the authour of the demonstrative physick , ripping up some fountains , both learnt himself and convinc'd others , by the very course of nature and by experiments masterly made , that cold water , full of a salt ( which he calls hermeticall ) with a mixture of sulphur , will grow hot . . the same may be seen in watred lime ; and in tartar , with the spirit of vitriol infus'd in it : the cause of all these is the same , viz. the fiery parts , fetter'd , as it were , in dry bodies , being set at liberty by the mixture of a liquid body , dissipate into vapours that liquour , it consisting of parts easily dissolvable . . hence , it appears , why cold fountains , sometimes of the same favour , are next neighbours to hot ones , viz. because they passe not through the same salt . . why some are more , some lesse hot , viz. either through the abundance of this salt , or through its nearnesse to the mouth of the fountain . . the same authour evidenc'd the constant lastingnesse of the heat to proceed , from the naturall reparation and recruit of the same salt ; when , extracting the salt , he found the remaining mud season'd again within three dayes : not by the raining of salt down out of the aire ( as that authour thinks ) but by the nature of the earth's being such that , mixt with aire , it turn'd into salt , or , salt was made of the moist aire and that mud. . it appears , again , why some fountains have wonderful vertues , either in benefit or prejudice of our bodies : why others convert iron into copper : others petrifie sticks and whatever is thrown into them : why some yield gold , others silver . . namely , because , flowing through severall sorts of earth , they rub off along with them little particles and dust ; so minute , sometimes , that they are not discernable from the very body of the water , and then the water is reputed to have such a vertue ; sometimes they are visible , and then the water is said to carry some such thing in it . . of fountains flowing out , brooks and rivers are made ; whose running , they say , requires the declivity of one foot in a mile : their reason is , because a line touching the earth , at a miles end , is rais'd nine inches ; artificers , therefore , adde three inches more , that it may conveniently run ; ( whence , the fountains of nilus should be almost a mile and half higher then the port of alexandria ) ; but erroneously : for , when ever the water running behind is so encreased , that it be able to raise it self above the water before , this rule of declivity changes . . among rivers , 't is strange one should swim upon and , as it were , run over another ; as , titaresus upon peneus , boristhenes upon hypanis : the reason is , the gravity of the one and the lightnesse of the other ; or , they will not mix out of some other cause , as , if one of them be oily . . the overflowing of rivers in summer proceeds , either from the melting of snow shut up in vallies , or from an abundance of rain , falling in a far-distant climate , and therefore not suspected by us ; as is evident , in nilus , niger , and some others of no name and scarce any better then brooks . . fountains , if they emerge into a hollow place of the earth , beget a lake : and , if this cavity happen in any elevated superficies of the earth , whether in a mountain or a high plain ; it comes to passe , that sometimes great rivers flow out of lakes : and sometimes vast eruptions of waters , without any appearing cause ; when a lake emprison'd in the bowells of a mountain , suddenly overflows and opens it self a way . lesson vi. of the aire , & those things vvhich are done in it near the earth . . the aire is evidently divided into two parts ; that which is habitable by animals , and that above : this last has no limits we can know of ; that first is contain'd in the sphear of vapours which ascend with a sensible heat out of the earth , that is , as much as the sun cherishes with its heat and renders fit for the life of animals : this , therefore , is comparatively hot ; the rest comparatively cold , which the snows and cold winds about the highest mountains testifie . a third , which they use to call the middle region , there 's none ; since the place of meteors is very uncertain , some residing near the earth , others above the moon . . out of the globe of earth and sea , by the power of the sun , little bodies are rais'd up , of the minutest bulk ; which , the sun deserting them , sometimes fall down upon the earth like drops , and are call'd deaw ; some drop from hard by , others from a great height ; for , all night long vapours descend , and the higher more slowly , both because they are higher and because every drop is lesse : hence 't is that chymists rather chuse the deaw that falls last , as also the summer deaw , these being the purest and subtilest . . from this deaw 't is , that the night grows cooler towards day-break ; though the first drops breaking and diffusing themselves , intends the same cold by the expiration of their cold parts . . the drops of deaw , especially the least , are perfectly round : the cause whereof is , because the water of deaw is very tender , and encompass'd in and bound together with a skin , as it were , by the more viscous aire about it . . as we see , therefore , bladders blown-up become round , because in that figure they are capable of most aire : so , every fluid body , when 't is straightned , must of necessity mould it self into a round form . and , this seems the cause why quicksilver so easily runs into little sphears : for , since the least fire will vapour it away , the least cold , too , must needs compresse it . . some deaws are sweeter then the rest , especially in the hotter regions ; whence , a kind of hony may be lick'd from the leafs of trees , and the bees are believ'd to make their hony out of deaw ; also , the manna , in calabria and arabia and other hot regions , is a kind of deaw ; cloves , too , and nutmeggs are thought to derive their sweetnesse from a kind of deaw which falls in the molucco islands : now sweetnesse proceeds from a concocting and digestion of moysture , into a certain oily softnesse and equability of parts . . frost is congealed deaw . a fogg or mist , properly , is the expiration of the earth or water out of a certain vent made by their native heat : for , we sensibly perceive foggs rising out of moist valleys , lakes , rivers and the sea : they presently fill all our horizon : then , for the most part , they rise either in the morning or evening , seldome when the sun shines hot : they rise , too , in great abundance , out of some certain place . all which agree not to vapours extracted by the sun. . and , because they expire out of putrid water , they stink and beget a cough . but , that which uses to rest upon mountains and in woods , especially when it rains , is another thing : for those are really clouds , not fogs , which either fall or are sustain'd by the leafs of trees ; whence , in certain islands , we read there 's no other water , then what is so gather'd and distill'd from trees . some mists are purely watry ; others have a kind of slimy muddynesse withall , deriv'd out of the quality of that body whence they are sublimated . . the nets we see in trees & hedges , as also those thrids that fly up & down sometimes , are made by the parts of the fog growing together ; or , of little bodies , too , rais'd up by the sun : minutest humid bodies gluing together other minutest dry ones ; that we may learn , out of these rude principles , how silk-worms and spiders webs and even flesh it self is woven . lesson vii . of clouds , rain , snovv and hail . . hitherto , we have kept near the earth . but , if the sun drives the vapours higher , they are gather'd into clouds : now , a cloud is a swarm or heap of minutest bodies elevated by the sun ; of such a crassitude & thickness , that , like a solid body , it either reflects or deads the light. . that 't is no solid body , is plain ; both from the tops of high mountains , upon which it appears like a mist , and does not much wet those that goe into it ; as also , from its generation , and rising up in minutest bodies . . and the reason is plain , why they hang above ; namely , because of the littlenesse of their parts , as , we see , dust thrown up staies a great while in the aire : besides , the motion of the aire hinders their descending ; wherefore , in a high wind , we fear not the rain , which , as soon as the wind is down , presently falls . . now , that which makes it fall is the forcing those little bodies into a straight place ; and , therefore wind brings rain , because it thrusts the little drops one against another and makes them bigger . . besides , the wind it self is often incorporated with the vapour and , by sticking to them , makes those particles , which before were too little , now to be big enough and fit for descending : as , when a warm wind rushes against a cold vapour , or contrariwise : and therefore , cold winds in the summer and warm ones in the winter chiefly bring rain . . but , because those things that are rais'd out of the earth ascend , not onely from the superficies , but out of its very bowells , too , through the pores : nay , they are expell'd and thrust out from the bottome of the sea , and the earth under it ; the sea-water forcing whatever is dissolved in the bottome , lighter then it self , to ascend : and , because there is a perpetuall vicissitude of vapours , bandy'd from the poles to the aequator , and from the aequator back again to the poles ; these consequents follow : . that little particles are drawn up into the aire and clouds , of all kinds of earth , clayey , stony , nitrous , bituminous , metallick , & whatever other sorts there are : again , of all sorts of plants , trees , roots , animals : all which being hurry'd up and down in the clouds from one part to another , are scattered ; and , if any where they come to find a convenient receptacle and nourishment , there such things or creatures are produc'd . . but , because some are apt to be form'd suddenly ; ( as , froggs easily grow out of mud ; and , 't is told by a man of credit , that a certain chymist , in a quarter of an hour , brought certain seeds to grow ) : it happens sometimes , such as these , too , rain out of the clouds . . so , it rain'd wheat , some yeares since , in the west of england , or rather , something like wheat ; and the same , i believe , those other miraculous rains are to be accounted , viz. that it rain'd not bloud , but a red water , something crasse it may be ; and not iron , but a kind of ironish stone ; so , too , not flesh , but something like flesh may have rain'd other where : for , we are wont to call things by the names of others which they resemble , especially when something of miracle is joyn'd with it ; so greedy we are of seeming to know or have seen something more then others . . snow and hail seem to be accidents of rain ; with this difference , that snow is rain whilst 't is yet in such little parts that it cannot descend ; but hail is it congeal'd , when 't is in such drops as are apt for descending : for , that the generation of snow is higher then that of rain , the tops of mountains witnesse , cover'd all the yeare with snow ; which they could not be , were they ever drench'd with rain . . and , that 't is congeal'd in minutest particles , is evident , to one that considers it , both from the height of its place and the very nature of snow ; for , the flakes are not of one continu'd body , but , as it were , ashes or little dusts made up together : its whitenesse , too , proves it , that is , its eminent virtue of reflecting light : for , suppose a world of little sphears , smooth and extreamly minute , made up together into one body as little as can be visible ; and , because every one of those convex superficies are apt to scatter light ; in its proportion , from every point , that quantity must needs appear extreamly white . . the rine , too , witnesses it , and a kind of snowy-hail we sometimes see like coriander confits : for , certain minute particles of snow are easily discernable ; and , if one look very curiously upon a flake of snow , one shall discern a composition without end , as it were , of distinct bodies coagulated . lastly , the whitenesse of froth proceeds clearly from the same cause . . hence , the doubts about snow are easily resolv'd : as , why the vapours should not rather immediately fall down in rain , then turn into snow ; since there needs a lesse intense cold for rain ? for , either they are admitted to be first in the degree of rain , before they become snow ; but descend not , because the parts are too little yet : or it must be said that rain does not signifie every moisture , but a dropping one , such as is not in so minute particles . the cause , too , of its softnesse is plain ; for , even diamant dust , if it be small enough , will be soft . . again ; why 't is often sexangular , or rather like a star with six rayes ? for , since six other equall circles just encompasse and inclose a circle ; if snow be compos'd of little sphears , the first composition will have six jettings out , to which those things may stick which , in motion , are apt to touch and stop against what they encounter : such a compound , therefore , is apt to be form'd into a star-like figure . . the cold , if it has been very intense and dry , slacken's before snow , because of the snow's moisture ; especially , if it come with a gentle , a south , or west-wind : as also , because a snowy cloud more compresses and straightens the aire near the earth ; whence , the vapours which rise out of the earth , being thrust and crouded close together , grow warmer ; and thus , too , snow , lying upon houses , makes the upper rooms warmer , by hindring both the entrance of the wind and the issuing of the vapours . in the same manner , also , it protects the earth and roots from the cold . . but , the warmnesse , which is felt after the fall of snow , proceeds from the free action of the sun , which before was restrain'd by a grosse cloud interpos'd against it : as also , because the cold wherewith we were infested , whilst the cloud hung over us , lyes now , as it were , subdu'd and imprison'd under our feet . that the falling of snow hinders sounds , 't is , because it deprives the aire of its agility . . hail is rain congeal'd in falling : it receives a figure either from the drops , or from the wind and the collision of the drops now growing hard , or else by chance or the concurrence of accidentall causes . . those that discern monstrous forms and shapes in it sometimes , polish and finish up , by the help of their imagination , certain rude lines : as 't is often seen in stones and whatever other figures . . that it so soon melts , the reason is , because there remains in it more water , then of the dry vapour ; the wind or congealing aire having light upon great drops : for , that this is the cause of congelation , our expecting ice and a rine the next day witnesses ; to wit , when the wind is grow'n sharper by the cold of the night . lesson viii . of fiery meteors appearing in the aire . . who 'd expect fire out of water ? yet we have it sometimes out of the clouds , and even out of rain : nay , in a very tempest , there stick to the masts things , the ancients call'd castor and pollux ; a wonder familiarly seen by the mariners . . but these and many such like seem rather to rellish the nature of vapours that reflect light , then of fire : for , both ( will of the wispe , or ) ignes fatui do not burn nor flame out , but only shine ; as also those dioscuri ( or castor and pollux ) have the form of a globe , which is not the figure of fire . again , flames , in a thin and tenuous matter , are not long-liv'd ; as appears in lightning , and in a candle , which we see sometimes blaze up , enflaming the smoak about it ; but suddenly extinguish again and retire to the wiek : the flames , too , which belch out of the vulcanian mountains are often but short-liv'd . . be this therefore a sure rule ; where-ever the figure is determin'd and constant , 't is no fiery or flaming matter : for , the way of fire is , to brandish pyramids upwards , with an uncertain motion ; the crasser matter pressing downwards . . besides , an ignis fatuus has been found fallen down in a slippery viscous substance full of white spots : the same , too , is the matter of falling-starres ; as , both a learned man hath found it ; & amongst our selves , when any such matter is found in the fields , the very countrey-men cry it fell from heav'n and the starres , and , as i remember , call it the spittle of the starres . . ignes fatui ( or wills of the wisp ) , then , are a certain viscous substance , reflecting light in the dark , evaporated out of a fat earth , and flying in the aire . they commonly haunt church-yards , privyes , and fens ; because they are begotten out of fatnesse : they fly about rivers , hedges , &c. because in those places , there 's a certain flux of aire : they follow one that flies them and fly one that follows them ; because the aire does so : they stay upon military ensigns and spears ; because such are apt to stop and tenacious of them : in the summer and hot regions they are more frequent ; because the good concoction produces fatnesse . . flammae lambentes ( or those we call haggs ) are made of sweat or some other vapour issuing out of the head ; a notunusuall sight amongst us when we ride by night in the summer time : they are extinguisht , like flames , by shaking the horse mains : but , i believe rather , 't is onely a vapour reflecting light , but fat and sturdy , compacted about the mains of horses or men's hair. . cardanus tells of a certain carmelite , that as often as he thrust his head into his coul , it flam'd out ; and that 't is usuall enough in spain , for sparkles to fly out of woollen garments rubb'd upon ones head : nor doubt i but these are reall fire such as uses to fly out of wood , canes , or flints , by rubbing or striking them , for these and such like are full , both of fire , and a certain vapour which is fewell for it ; whence , when many hot parts light upon a considerable part of the vapour , they scorch and kindle it ; whereupon , after such a production of fire , there remains in some an offensive sent , as of burning . . the hair of horses , and cats , as also sugar rub'd together in the dark , are said to produce the same effect : the eyes , too , of some are said to sparkle , viz. when they shine with spirits , and reflect the light as if they were glasse . yet doubt i not but the eyes may , by some preternaturall disposition , yield reall light ; it seeming evident in cats . . but , that the most part of these are idle stories , i collect from this experiment , that it has seem'd , even to my self sometimes , that my chamber was all light ; and i saw every thing plainly : when , notwithstanding , i have often catch't my self in it , and found mine eyes shut all the while ; and that my memory within , was working upon those thiings which i thought i saw : and sometimes i found that i err'd , too , imagining some things to be in this or that place , which indeed were not . . falling-stars are a certain viscid or slimy matter , rais'd out of the earth in very minute parts , and coagulated in the aire ; which , when , in its fall , it comes within our sight , beautifies all its way with reflected light : yet , sometimes , it falls not downwards ; but , being carry'd traversly by some motion of the aire , 't is call'd a gliding star , 'till , either being dissipated , or by some other accident , 't is seen no more . . caprae , trabes , bolides , faces , dolia , clypei , ( as the ancients call them ) , or whatever other names such meteors may have ; whether they are reall fires , or only certain clouds brighter then ordinary ; neither is it deducible clearly enough out of histories , ( they relating scarce any thing save that they burn in such a figure ; but that they take burning for shining 't is very credible , even from hence , that they mention no tokens of their burning ) ; nor have i ever met with any very curious observer treating of this subject . lesson ix . of truly fiery meteors , hanging in the aire . . the true fires , therefore , are lightnings , dragons , and those they call fire-drakes : for , first , they have not a clear brightnesse , as falling and gliding stars have ( which is almost a sure sign of reflection ) , but a dimm'd one ( from the condition of the matter ) as it were with smoak , as we see in our fires ; though this rule may fail on both sides , unlesse it be prudently apply'd : again , they are short-liv'd : thirdly , the ashes of dragons are often seen , and the effects of lightning are well known . the nature of fire-drakes is like that of lightning or the blazing of candles ; so that 't is , unquestionably , a sudden kindling of an oyly vapour ; and it varies its figure with every motion , as fire uses , according to the various dispositions of the combustible matter . to apprehend the causes of these things , . let us imagine the hottest days effect that upon the earth , which , upon a chymicall matter , the most intense heat does , that , after the gentler , is apply'd to extract oyles , that is , the most glutinous and crasse moisture : suppose that , out of fat and soft grounds , they raise vapours , not liquid , but compacted with a deal of dense matter , not without a vast abundance of fiery parts imprison'd in them . . that these vapours can neither be elevated into a very high station , nor long sustain'd above : that , yet , to the proportion of the heat , they are carryed higher ( according to the nature of the region and of the concurring causes ) in one climate then in another : and that , through the motion and tumult of the clouds , these vapours meeting with one another , being of a glutinous substance , stick together and are constipated ; that , being constipated , they are kindled , and , being kindled , either break out or are thrown out . . again ; this matter , being the heaviest of all that are elevated , will be hurryed downwards , as we see in golden-gunpowder : for the dilating of the fire makes and applyes an impression of the adhering matter , that way which the matter leads : it breaks , therefore , through the clouds , there , where 't is easiest descending ; and being , in the time of its passage , for the most part , directed obliquely , because the cloud is thickest towards the earth , 't is , so , hurry'd to us . . when nothing but the flame approaches us , 't is said to lighten : when , without thunder and in a clear season , any lightnings appear , we say it flashes . . hence , 't is apparent enough how thunderbolts come to be darted out of the clouds : for , the fire in the clouds being extreme violent , it bakes a light stone , like a pumice or those which are made in furnaces for metalls : and that , having the fire still adhering to it , and being light of its own nature , is carry'd , like an iron kettle or earthen porringer in water , and descends with violence . . again ; 't is evident how thunder is caus'd : for , that most suddain rarefaction of fire cannot be made , without a most swift compression of one cloud to another ; nor this , without a mighty noise , such as we hear at the suddain extinguishing of a violent and intense fire , and at the dashing together of the waves of the sea in a storm . . from the different matter of the lightning there happens the variety of different effects : as , when , the purse or scabbard being intire , the mony or the blade is melted ; it proceeds from hence , that , in the lightning , there is the nature of those salts , which serve to melt metalls and yet have no power upon slighter subjects : when the wine congeals , the vessell being broken ; 't is a sign of cold spirits in the lightning , by which liquid things are rendred consistent and hard things are broken ; as we see by the congealing of water in a glasse or earthen vessel close stop'd : when water will not quench it , it has a mixture of wild-fire in it , such as we see in burning fountains . . iron is us'd against lightning , because 't is a kind of matter something akin to lightning , and draws the volatile spirits to it self , so that it does other things no hurt : mushromes , too , come on the better for tempests , because the rain which accompanies them is warm and fat ; as the fields of aetna and campania are rendred more fruitfull by the eruptions of the mountains , because much heat and fat matter descends withall . . hence , that they call the fiery dragon is a certain weaker kind of lightning : it s livid colour , and its falling without noise and slowly demonstrate a great mixture of watry exhalation in it : nor is there any thing else of singular in it worth taking notice of ; for , 't is sufficient for its shape , that it has some resemblance of a dragon , not the expresse figure . lesson x. of the generation and nature of winds . . now , it happens that the exhalation shut up in the clouds is , sometimes , very lean and dry ; and then , instead of lightning , a wind is pufft out : sometimes alone , and then 't is call'd ecnephias ; sometimes mixt with flame , as when a fat and lean vapour are mingled together , and then 't is call'd prester . . but , if it breaks out through a narrow passage , and is whirl'd about like water , 't is call'd typhon or a whirlewind : for it brings down with it , even to the earth , that whirling impetus , and , being reverberated , as it were , back into the aire , hurries away , wrapt up in it , whatever it meets unable to resist it upon the earth : all these winds are properly call'd storms and stormy . . some signs , by the providence of god , they send before , of their coming ; as all vehement things do : which proceed hence , that , in corporeall things , a part must of necessity be made before the whole ; and , in motion , the weaker must goe before , the violenter must follow . . hence it comes , that animals have a kind of sense of storms before they come . again , because , for great things , there must precede great preparations ; a change in the causes may , by diligent persons , be observ'd : so mariners foresee future storms , by the sun , the moon , the clouds ; and shepheards , heardsmen and such others , by their cattel . . out of what has been said , 't is easie to conceive the generation of winds : for , if a vapour or exhalation be either so dry or so scatt'red that it cannot coagulate into great drops , it descends in the form of dust ; and , where it first finds resistance , there it begins to take a determination and make , as it were , a channell of its motion . . and , that way the first parts have gone before , the later follow , ( by the force of consequence , now , and the impetus of the aire ) and make way for others : thus , therefore , they run through the horizon , till either the sun has suck'd them up again , or their atoms have adher'd to other bodies , especially moist ones , with which they are easily incorporated . . hence , may be resolv'd the questions about winds : for , first , if the exhalation be high , it makes the rack ride , but it comes not near the earth : when there happen to be many exhalations of severall lightnesses , the clouds appear to ride severall ways : when the causes of the exhalations hold out pertinaciously , the wind lasts longer from the same corner : when the vapours , flowing in from one corner , are more dense and abundant then from another , then the wind is more vehement on that side . . and this happens , either from the quality of the earth whence they are extracted : for , out of a moist and cold ground , the vapours are densest ; out of a moist and hot , most abundant ; out of a dry and cold , they are still lighter ; out of a dry and hot ground , they are lightest of all . . as also , their way is to be consider'd : for , they mix themselves with the vapours through which they passe , and are imbu'd with their qualities . again , much is to be ascrib'd to the heat which dissolves them : for , a moderate heat dissolv's those that are more subtle , a violenter those that are heavy and thick . . it happens , too , that the nature of the corners from whence the wind comes , is accidentally alt'red sometims : for example , if , from the north , for the most part , come dry and fair-weather vapours ; it may well fall out that the vapours carry'd by the south-wind , when they are past us towards the north , meeting with a stronger north-wind , will be brought back to us pouring down rain ; and so , from a serene corner we shall have rain , and , contrary-wise , fair weather from the south . . out of the same principles , may be understood the reason of etesiae , that is , winds that alwayes return at such a set season of the year : for , the originall causes of the winds being certain and determin'd , ( among which , the melting of the snows is the principall ) , which return at set times of the year ; the winds , too , unlesse something interpose , must needs return at the same seasons . such are the northern etesiae : these constantly blow , in italy and all over greece , at midsummer ; rising , as i believe , out of the alpes , not from the farthest north , since they are not felt in the intermediate regions : and they rise out of the earth after 't is moistned with the snow ; for the snows are said to melt about the end of may ; whence , 't is plain , they that blow at the middle of iune cannot be rais'd , but out of the earth already well watred ; unlesse perhaps some snows hid in the valleys are then first sensible of the sun's violence , or that the sun should draw a cool breath of aire out of the snows without melting them . . such are the east-winds , which we have in england , out of russia and muscovia , about the end of march and beginning of april , for fourty dayes together sometimes , upon the first dissolving of the snow in those parts . such are the west-winds the west of england is subject to , at the latter end of summer and beginning of autumn ; brought to us from that part of america under the same meridian , over a vast sea and out of moist regions , whence , for the most part , they are rainy . . it appears , out of the same principles , why some winds are heavy and low , others light and high : for , 't is plain , these conditions must needs follow the quality of the subject whence the vapours are rais'd , and of the heat that raises them : for , as chymists , with a soft fire , extract the purest and lightest spirits , but , with a violent heat , heavy and troubled ones ; so nature , too , with a moderate & gentle heat , raises the purer & sublimer winds ; but the heavier , more vehement , and lower winds it forces out with extreme heats . . hence , again , 't is plain , some are wholsome , others hurtfull : since , their effects must needs follow the condition of the nature of those vapours whereof they consist . but , we must note , that some winds have very guiltlessely got an ill name : for , those that in one place are unwholsome , in another are wholsome . . the sea-winds are commonly unwholsome , as bringing along with them heat and moisture , the principles of corruption : yet , in very hot regions they are wholsome ; and sometimes in the height of summer , because , then , they refresh ; and because they are drawn up higher by the sun , they are penetrative , without any harm . . 't is to be noted , that the winds always take the compasse of the greatest circles : because , being thrust out with violence , they take the shortest line ; which , upon the superficies of a sphear , is the arch of the greatest circle . lesson xi . of earth-quakes and their effects . . but , because we have said , there are caves under ground ; and both our experience of pits sunk , and many extraordinary effects demonstrate fire & water , there , too : there must necessarily be notable effects of the vapours extracted out of the bowells of the earth . . if , therefore , out of some subterraneous humidbody , vapours chance to be rais'd , by a subterraneous fire , too ; and they prove too bigg for their place : 't is manifest that , alwaies increasing and becoming condens'd , by the continuall accesse of new vapours , they 'l seek themselves a way out , according to the force they have , where ther 's the easiest passage . if that chance to lead into any vast under-ground cave , the earth will quake with a great impetus and groan ; but nothing will appear above ground . . but , if the easiest issue be towards the superficies of the earth , the vapour will burst out through it : and , if it be noxious to beasts or birds , 't will bring either death or a disease along with it ; making with the eruption either a gaping hollow or a mountain , according as the earth either sinks or is sustain'd and , as it were , vaulted . sometimes 't will bury and swallow up cities ; sometimes transport vast pieces of earth ; and produce other effects , whereof we find expresse memorialls in history . . the prognosticks of an earth-quake , they say , are an infection of the fountains with a sulphurious savour ; an unusuall calmnesse of the air and birds ; a swelling of the sea without any apparent cause ; blackish streaks under the sun of an unusuall length : all ( if they are truly prognosticks , and not onely accidents , which , sometimes and not for the most part , happen ) are the effects of a spirituous vapour bursting out from the bowells of the earth . . they are said to happen chiefly in the spring and autumn , therefore , ( if the opinion be true ) because the superficies of the earth , being warm , becomes slacker with the rain : but , i should rather believe it a chance that many should be recorded in histories about these seasons ; for , both winter and summer have felt their earthquakes , and in the torrid zone , where they are most frequent , the differences of spring and autumn from the other seasons are very inconsiderable . . the sea-shores are most subject to these motions ; because the subterranious flames and fumes receive no little nourishment from the sea ; and the moisture which soaks into the earth , renders it very fit for breeding vapours . lesson xii . of the meteors of the other parts of the world ; and especially of comets . . these accidents of our orbe , and its parts , which are usually call'd meteors , must necessarily be found , too , in the other bodies , which , we have said , are enlightned by our sun : and that , out of the nature of quantity and the mixture of rare and dense ; if they have their severall degrees and differences . . nor in these only , but in whatever bodies besides , wherein alterations are wrought , by the operation of fire upon denser matter ; for the same reasons . . 't is evident , too , that our sun cannot warm and enlighten all those bodies that reflect light to us : for , if it were as far distant from us , as astronomers suppose the sphear of the fixed stars , 't would appear to us to be but of the sixth magnitude ; and consequently , it could not communicate to us any considerable either light or heat : how much lesse , in the situation where 't is , could it reflect so far as to us a light of the first magnitude , from any star so far distant . . adde to this , that one that should collect , from the proportion of the basis of a cone to its axis , how much light the sun could reflect to us from the eighth sphear , would find it absolutely invisible . besides , the very aire , through which the light passes , by little and little drinks up and extinguishes it : whence , in a thicker aire , it spreads it self a lesse way , then in a rarer ; so that , in so vast a journey , 't would be utterly deaded and not seen . . a meteor of the planets , perceptible by us , is a comet ; which its very-little parallaxis convinces to be , sometimes , sited above the moon . . that 't is not fire , its constant figure ; its tayle , not oppos'd to its motion but to the sun ; its lasting consistency ; its matter , light and to be seen through ; and lastly , its motion , more regular then we observe in fire , largely convince : farther , that it has nothing of fire but the colour : adde to this , that fromundus , with his very eyes , discern'd the tayle of that comet in the year , to consist of the reflection of the sun 's light . . be it , therefore , a vapour which partly reflects the light of the sun , partly , drinking it in , either repells it back again to us by refraction from it self , or , letting it through , by reflection from another body : and , its fore-part will be the head , it s hinder ( whether part , or something only accessnry to it ) will be the tayle . . and since , by this generation of a comet , any figure of its beard , any motion , any winding of its tayle , but , for the most part , the opposition of its tayle to the sun and the lesser light of its tayle then of its head , may be fairly solv'd ; this intire subject is clearly display'd . . out of the same principles may be deduc'd , that fading stars are comets ; but , so far off , that the secundary or refracted light of their tail , by reason of the height , either cannot be distinguisht from the body , or cannot be extended to us , because of its extreme faintnesse : as also that , its motion cannot be discern'd . . even these , therefore , witnesse that there are meteors among the very fixed stars ; and those , so much the more constant and lasting as the bodies out of which they are extracted are larger . lesson xiii . of the ebbing and flovving of the sea , and its accidents . . since , out of what has been said , it appears that the gravity of the vapours and the straightnesse of their issue are the cause of the violent motion of the winds ; and that the heaviest vapours are extracted out of the earth , when 't is well moistned : it becomes evident that , where vapours are rais'd out of the sea only , they are lighter ; & that , if they be turn'd into winds , without being straightned , they will be calm ones . and , since , in the great pacifick sea , in the indian & atlantick ocean , quite through the whole torrid zone , there are vast waters , & , consequently , in some measure , secure from the incursion of shore-winds : there must needs be light vapours rais'd up by the sun through all that tract , which , the sun retiring , must turn into winds , taking that course which the suns rarefaction of the aire makes most easie ; & this , all the year long ; & consequently , there must be a continuall east-wind . . and , because the aire naturally moves in a circle , still yielding and flying before it self ; it must needs turn again by the shore-side , drawing along with it the vapours it finds ; yet , not so constantly as under the aequator , because of the shore-winds . . moreover , eye-witnesses affirm , that east-winds range for degrees of latitude from the aequator on each side ; and west-winds the next ten : and , of longitude , in the pacifick and indian sea , about eleven thousand italian miles ; and , in the ocean which leads to the new world , from the canaries to the bay of mexico , about degrees , that is , some four thousand more such miles : so that , if we allow the aequator twenty one thousand miles , these winds possesse , thus , almost three quarters on 't . . since , therefore , notwithstanding its calmnesse , this wind carryes great ships eight miles an hour ; it must of necessity drive the waters themselves , in the middle , with great violence , towards the west : whence they must needs overflow upon the shores , and return again from the shores to the middle ; and , where they meet any shores , withstanding their course to the west , be reflected towards the east : as also , they must rush into all the bayes , and , after a determinate time , return again , according to the winding of the shores ; the account of which time must be taken from the common channell . . we have found , therefore , an apparent cause why the sea should fill the shores with its motion towards the east and west , and empty them again , with a constant course , which we call the ebbing and flowing of the sea. that this proceeds from an extrinsecall cause , & not because the water moves lesse , that is , slowlyer then the earth , appears from hence , that the ebbing and flowing is discover'd , in some places not very deep , to extend not above six fathoms ; all the rest of the water is calm and like a lake : whereas , if the ebbing & flowing follow'd from the motion of the earth , it must alwayes be mov'd ununiformly from the bottō upwards ; without any sensible beginning of the contest of the waters . . hence the reason may be given why the flux proceeds from east to west & back again , in the open sea ; why no swelling should be perceivable in the mid-sea , but only at the shores : the reason is , because there are no marks by which we might take the height of the sea ; for 't is found to swell there , too , if any island occurre , how far soever from any other shore . . moreover , why there should be a continuall flux of the sea observ'd , towards the west ; viz. because this wind in the middle of the sea perpetually drives the waves towards the west . . why , too , the flux should be more vehement in one part then in another : viz. from the abundance of waters flowing in , and directed by other causes the same way ; as , by rivers , or the repercussion of the shores beating the greatest part of the floud together against some one shore . . also , why there should be six hours flood , and as many ebbe : for , since the wind proceeds from the sun , and the sun enforces its activity upon one part , for six hours , and remit's it as many ; there must needs be the same generall periods of its effects , that is , of the sea's motion . . but , since the moon , too , may suffice to encrease the wind ; and , the nearer 't is the sun , the more its power is conjoyned with the sun 's , the farther 't is from the sun , the larger and stronger its force is upon the ocean ; who can doubt but the flux must be encreased twice a moneth ? . in like manner , since the sun is twice a year in the aequator , in which place , as just in the middle , it most vigorously rayses the wind : every six moneths , too , the flux must be more eminent ; but especially about autumn , because , between the tropick of capricorn and the aequator , it rains mightily night and day , for three moneths together after the summer solstice . . but , that the flux returns every day about an hour later still , 't is from hence , because the flux and reflux proceed from opposite causes ; whole forces , before the victory , must needs be but equall , and , by reason of their equality , require a convenient time . whence , allowing six hours for the flux and as many for the reflux , each must be allowed its intervall ; which , in the thames , ( if i well remember ) is little more then a quarter of an hour : this space , therefore , thus , four times repeated , in one day , makes somewhat more then an hour . . sometimes too , the winds stop the flood ; insomuch that , without a miracle , the flood has three times advanced and been beaten back in the thames , by the force of an opposite wind . lastly , it appears why , in some seas , there 's no mention of flux ; as , in the red , the euxine , the meotis , the caspian and baltick seas : ther 's the same reason for them all ; that they are but little seas , and have but narrow entrances ; that , vast rivers running into them , their superficies is higher then the ocean's ; that their current into the ocean is so strong , that the sea , especially the mediterranean , whose flux is not very high upon the grecian shore , is not able to repell it . lesson xiv . of the motion of the earth , and the causes of it . . since , therefore , the upper part of the water is continually mov'd towards the west : ( and , as , because the water in the middle runs one way , that by the shore-side must needs run backwards ; so also , because the superiour water is hurry'd towards the west , ) that which is next under it must needs be driven back to the east , and whatever so adheres to it that there is no cause of separation ; that is , which will easilyer be driven towards the east then be separated from the lower water . . but , one part of the lower water is not separable from another , unlesse it either ascends into the place of that above it , which another part , supervening , prevents and hinders ; or else , unlesse it repells that which is easternly to it , and that again another , and , in the end , the last , the shore that 's oppos'd against it , which is incredible and impossible : the whole body , therefore , with the earth adhering to it , must needs be driven towards the east , unlesse there be some resistance stronger then the impulse . . whereof ther 's none in its gravity , because that motion is not contrary to the motion of gravity ; and its bignesse even much facilitates the motion : the earth , therefore , will be mov'd in a circle , and turn round about its own centre , because this impulse is made in a circle . . again , because 't is almost impossible this impulse should be equall on all sides , and cause a pure rotation about the centre ; there will , of necessity , a progressive motion be mixt with it . . and since , as a body cannot be , but in one place , so neither can it move but in one line : all the motions which astronomers assign the earth must , of necessity , compose one line ; and , if the lashing or impulse of the under-water advance the earth in that line , 't will be an adequate cause of the motion of the earth . . now , astronomers teach , that the earth , continually turning about its own centre , runs under the zodiack ; its axis retaining a certain inclination to the axis of the zodiack : wherefore , when we have found out a line , in which the earth , being thrust on , will observe this motion ; the flux must be imagin'd to move the earth according to that . . astronomers prove these motions of the earth : because , otherwise , greater motions of greater bodies must be suppos'd ; and those , neither themselves constant , nor proportion'd to the bodies , and , besides , more entangled , both in the stars and in the sun it self , as is apparent by its spots : which if you say make not up a perfect astronomicall demonstration , that maxime must be renounc'd upon which all astronomy depends , viz. that the phenomena ( or appearances ) are to be solv'd the best way we can . . again ; because there follows a variety in the fixed stars , from the diversity of the earth's position in its orbis magnus ; when there 's once found out a telescope , of such perfection as to be able to distinguish that variety , we may expect a geometricall demonstration : and because , for the same reason , there must needs be a variety of reflection from mars and iupiter ; when the laws & rules of light shall be better known , there will not want a physicall demonstration . lesson xv. of the oppositions against the motion of the earth and , of its effects . . astronomers object , that this annuall transferring of the earth would cause a diversity of elevation in those stars which are near the poles , and a variety in the appearing bignesse of those in the zodiack : which , since we see not follow , neither is there any such thing as this annuall motion of the earth . . 't is answer'd ; the vast remoteness of the fixed stars renders such variations imperceptible : and , that their distance from us is sufficient to produce this effect , may be collected from the effect it has upon a telescope ; which , though it amplifies so much the planets and even saturn himself , yet adds nothing or an insensible matter to the fixed stars . . out of this motion of the earth rises , first , the reason of night and day : for , since , in a determinate time , 't is roul'd about its centre , ( suppose in about hours ) , the things that are in the heavens must needs appear sometimes , and otherwhile disappear , to a determin'd place of the earth : and , such a variety , in respect of the sun , makes day and night ; in respect of the other stars , a variety not own'd by any common name . . again , by its motion under the zodiack , it attains various conjunctions with the other planets . . lastly , in that it carries its axis turning still towards the same parts of the heavens , it comes to passe , that the part of the earth , enlightned by the sun , possesses sometimes greater sometimes lesser parts of the parallells , according to which the diurnall motion proceeds ; and , consequently , that the dayes are longer and shorter . . thence , too , is it , that the sun becomes more perpendicular at one time then another ; whence the natures of winter and summer are deduc'd , and the varieties of declinations , descensions and twilights . . but , that the winter is shorter then the summer , proceeds from this , that the motion , through the inequality of the bodies rais'd up in the winter time , is swifter then in the summer . . an effect , too , of the motion of the earth is the carrying of the water about with it ; but not the tyde : first , because , if the earth should stand still , the water would stand still withall ; since , as we have said above , ther 's no impetus but from the gravity , and such there would be none in the present case . . again , ther 's no cause of the unequall motion of the water ; since , ther 's the same quality continually in the movable , and not by skips . . again , if the whole water of the sea were so mov'd , 't would drown the mountains : lastly , the periods of the earth's motion do not agree with those of the tyde 's . . but , that the flux depends on an extrinsecall agent , which impells only the superficies of the sea , is most evident ; by the experiment of a late diver , that discovers ther 's no flux in the bottom of the sea. lesson xvi . of the motion of the aire vvith the earth ; and its effects . . out of what has been said , 't is manifestly inferr'd , that the aire , which clings to the earth , is roul'd , in the same manner , about or rather with the earth : for , since , both by the nature of quantity and the weight of its gravity , it presses towards the earth , and sticks to and incorporates with it ; it cannot , without some greater force interposing , be separated from it : since , therefore , in it , ther 's no resistance against motion , and onely a resistance against being torn away from the aire next it , which takes another course ; and this resistance is not greater then that against being torn off from the aire below , and perhaps not so great , ( since aire is so much the lighter the higher it is ) ; t is evident , it will follow the earth : wherefore , to the very confines of the emanations of some star , that has a different motion , the whole aire will be roul'd about with the earth . . and , experience also proves it : for , else , the twilight vapours , comets , and birds above the highest mountains would seem hurryed extream swiftly towards the west . again , 't is plain , those clouds of dust , which we call the sun's spots , fly along with the sun ; and that , the same way , ( as appears , because the bright parts are burned still the same way , ) notwithstanding they are judged to be a hundred miles distant from the sun. the vapours , too , of the moon are found to be carried about with the moon . . from this motion of the aire it follows , that bodies in the aire it self are so moved , in respect to the parts of the aire and the earth , as if there were no motion at all in neither ; they being carried still along together with the aire it self : as , one in a ship , under saile with a constant wind , exercises the same motions and with the same facility in the ship , as he could do if she stood still . . wherefore , arrows , shot just upright , will fall in the very same place ; or , shot towards the east , they 'l fly no farther then if shot towards the west : the motion of the earth will raise no wind , &c. this , too , will be certain , that the aire cannot be carry'd lesse then the earth ; as , one that sits in a coach cannot rid lesse ground then the coach it self . . nor can all these be made good by an impetus , conceiv'd upon the earth , and remaining in the movable after its separation from the earth : for , neither could birds retain that impetus for many hours together , at least , without any notable diminution ; and lesse could little bodies , for many dayes : nor could that impetus carry an arrow as swiftly acrosse , as directly . besides , as those that swimme against the stream feel the strength of the stream under water ; so , one that should move towards the west would feel the aire to be carry'd towards the east . . much lesse , by the force of its circular motion , will the earth throw any thing laid upon it into heaven : for , circular motion has no such property in its own nature ; since 't is still about the centre , and , by consequence , keeps every thing , according to its own line , in the same distance from the centre : but , those things we see thrown off from wheels , are so , by reason of their adhesion , and the mixture of a straight motion with the circular ; as also , because the centre of gravity of such thrown bodies is remov'd , from that position wherein it was sustain'd by the body under it . lesson xvii . of the causes of the motion of the moon and other stars . . since , supposing this motion of the earth , the moon is carry'd with it about the sun , and keeps alwaies the same side towards it ; 't is fairly convinc'd to have a kind of adhesion to the earth . . yet , not a magneticall one , being it changes not its aspect , nor has any declination , for its approaching the poles ; nor , though it hangs loose , does it come to the earth : 't is , therefore , an adhesion of gravity . . and , since gravity proceeds from the motion of things descending towards the earth ; the moon must be situated within the emanations of the earth , be carry'd about the centre of the earth , and about the sun. but , because it has a propension of its own towards the earth , it is not carry'd so swiftly as the emanations themselves ; its progresse being , according to astronomicall observations , but about a . part every day . . and because , under the zodiack , ther 's a perpetuall tumult of vapours which ascend , and being come up to a certain height , turn off from the torrid zone towards the poles ; the motion of the moon is compounded of a motion under the ecliptick and towards the poles . . it is not , therefore , carry'd purely under the ecliptick : but , because 't is mov'd in a sphericall superficies , and by the shortest line , that is , by a greatest circle ; it will cut the ecliptick twice every intire course of its defects , that is , every moneth . . in its opposition and conjunction to the sun , the body of the moon , that is , the whole complex of its solid and vapours , becomes lesse heavy : in conjunction , because its nearnesse to the sun and the sun 's stronger reflection from the earth raises more vapours in the moon : in opposition , more vapours are rais'd out of its , naturally , colder part ; and in the upper part ther 's allways abundance . . wherefore , the moon , in these positions , must rise higher from the earth , and , in the quadratures , that is , about the passages from the first to the second and from the third to the fourth quarters , appear bigger . but , because that part which looks towards the earth is allways the heavier , it never turns t'other side towards us . . nor is there any fear least the moon , falling by reason of its weight , should o'rewhelm the earth ; both because 't is furnisht with a great deal of fire and vapours lighter then the emanations of the earth ; as also , because very gravity it self , near the confines of the earths emanations , is not so powerfull as 't is here lower . . but farther , because 't is hurry'd about two thousand miles every houre : whence , were it made of solid iron , it could not fall down ; since , we see iron bullets sustain'd in the aire , by the power of guns , though their motion be not two hundred miles an houre . . out of what has been said , we may easily argue concerning the other great bodies . for , all those that belong to our great orbe either are mov'd about the sun , as being certain other earths : or else about other stars , as the moon about the earth ; such as are the medicean stars , and the companions of saturn . . and , because we discover suns among those other parts of the world ; 't is very credible there are proportionable planets dispos'd among them , too ; and that all those bodies are mov'd in the manner of ours . . the sun it self must , of necessity , turn about its own centre : else , certainly , since 't is fire , 't would appear divided into pyramids ; and , if it were born along with a progressive motion , 't would shew a vast train of flames like a comet . . lastly , since 't is all full of caverns belching out flames , and fire flames out according to the nature of its fewell ; these flames must of necessity flash out with a fierce impulse against the sides of the caverns : and , because they have an eminent proportion to the body , they must shake the entire sun and turn it that way the motion lyes strongest ; which , the phenomena of its spots and bright parts testify to be according to the zodiack . lesson xviii . of the primum mobile , the duration , and quiddity of the world. . but , because this fire , which bursts out from the sun's bowells , is it self mov'd , too : either this motion , which is the mother of all other , must spring from it self ; or else we must come to an incorporeall agent . . but , that bodies which rest , how many soever they are , cannot start of themselves into motion , is most evident : for , being suppos'd to rest , all their intrinsecalls are suppos'd , without that effect which is call'd motion : since , therefore , all things remaining the very same in the causes , there cannot be any change in the effect ; and yet , supposing motion , there would be a change ; 't is plain , there cannot any motion spring out of them , without altering first somewhat in the causes , that is , in the bodies . . moreover , every part of motion being a new effect , the same evidence convinces that motion cannot be continu'd , without some cause be suppos'd continually altering the first body , on which depend the motions of all the rest . . since , therefore , we have pursu'd the originall of motion into the very bowells of the sun : we must conclude , that there is a mover of another nature , viz. an incorporeall , from whom fire receiv's the power of moving ; who , being of an immovable nature , establishes the centre of the sun , that it may be the fixer and , as it were , basis of all things rouling about it . . that motion cannot be infinite , the same argument convinces which made it plain before , that all permanent quantity is finite : for , suppose backwards from this instant or now wherein we are , an infinite time already past , there must be infinite hours past ; some one , therefore , will be infinite others distant from us ; and , in that one , a determinate now , which , with this present instant , must enclose an infinite on both sides . . nor , if the computation be made forwards , will the reason differ : for , there must still be infinite hours to come ; and one of them will be infinite others distant from us ; and , in that one , a certain now terminating an infinite , which is impossible , whereas yet , what is future is , in that very respect , possible . . the world , therefore , is neither from nor to eternity : because , the world includes the motion of bodies passing on in a determinate order , and , as it were , consists in this . 't was , therefore , created ; but , not for it self : for , if it could have deserv'd to be made for its own beauties sake ; upon the same title , it would endure for ever . it rests , therefore , that 't was made for something else ; which cannot be successive , since the same evidence , with which we have disputed about motion , convinces that no successive thing can be eternall . the world , therefore , is made for some permanent thing : but , there 's nothing permanent found in nature , except the rationall soul , for whose sake the world could exist : spirits , therefore , born in bodies and perfected in them , ( not such as are purely abstracted from body , who have no use of corporeall instruments ) are the end for which the world was made . . and , the world is nothing but a kind of vast wombe , in which these spirits may be begotten and brought up ; which has so many cells as there are severall races of these spirits . our cell is the earth we inhabit : the cells of the rest are those masses of the celestiall bodies ; except the solar ones , which are the basest of all the rest , and , as far as we can guesse , only ministeriall . . the quantity of the world , both for its extension and duration , is such as may fitly serve for the breeding up so many differences of spirits : providing the cells , according to the severall kinds ; and giving every cell the bignesse and duration which was sufficient for the number the architect design'd . . the figure of the world is not rendred uneven , either with hollownesses or jettings out ; since , the notion of vacuum excludes both these : wherefore , 't is either sphericall , or of some other curvilineall figure , which , most concisely , covers and encompasses so many and such great cells . . the exteriour rimme of it is not compos'd of any solid body , but of thinnest vapours exhal'd out of the outmost bodies : unlesse , perhaps , there be reserv'd in nature some farther use of the outmost body , which we know not of . peripateticall institutions . fourth book . containing that part of metaphysick , which explicates the essentiall notions of bodies . lesson i. of the divisibility of substance , into formall parts . . since water is , manifestly , lesse divisible then aire ; and yet they are but one , quantitatively : if they are more then one according to their substance , there must , of necessity , be a reall composition of quantity to substance ; since unity and plurality are not distinct from the thing whose they are . . but , if they are not two substances ; since there cannot be a different proportion of the same thing to it fels , & yet the proportion of quantity to the substance in aire is greater then in water ; it must needs be , again , that ther 's a reall composition of quantity to substance and , therefore , a divisibility . . whence , t is inferr'd , that substance , as t is condistinct from quantity , is indivisible ; since quantity is divisibility . . as also , that the notions of rarity and density consist in the proportion of the quantity to the substance whose it is : since rare bodies are more and dense less divisible . . you 'l object , such as are one in quantity are one in substance , too : but , the whole world is one in quantity ; & that rigorously , since , there are no parts actually in a magnitude : therefore , either quantity is a distinct thing from substance , or else all bodily substance will be but one thing , really and materially , whatever may be imagined of an intellectuall distinction between them . . t is answered , 't is a false assumption , to say , those things which are one in quantity are one in their substances , too . to that which is objected , that all things would be really and materially one ; t is answer'd , either 't is but the same which we call to be one quantitatively , and then 't would be shew'd what inconvenience would follow , that consequence being admitted : or else , that term , really and materially , would be explicated ; for the arguers seem to insinuate that it signifies , abstracting from our notions , that is , they would be one in no kind of unity whereof we have any notion . . all things , therefore , according to that unity which follows the notion of quantity , ( and that is accidentall , ) are one : but , according to their substances , and that unity which follows the notion of substance , they are many . . it follows , from what has been said , as oft as any division is made , the substance it self is chang'd , which is subjected to the quantity , according to the intrinsecalls of substance , as 't is condistinguish't against quantity : for , division being that whereby more are made of one ; and , they not being made more according to the proper unity of quantity ; this plurality must , of necessity , be in the substance as 't is condistinguish't against quantity ; wherefore , the unity , too , which is destroy'd , was in the substance , as condistinguish't from the quantity : since , therefore , vnity superadds nothing to entity , but a negative notion of indivision ; it comes to passe , that a change cannot be made in the unity without a change in the entity , and consequently , that the entity is chang'd . . but , the entity is not so chang'd , that two entities should be made out of nothing ; but out of one that existed before : otherwise , there would not have been made a division . there was , therefore , a power or possibility in the substance , to be many ; as , in many , ther 's a possibility to be made one again . . the substance , therefore , is chang'd , in some respect ; and remains in the many , according to some part of its power : wherefore , 't is divided according to its own proprieties ; and , there is , in substances , divisible according to quantity , another proper divisibility , into the power by which it can be what it is , and the act by which it is what it is ; or , into the matter remaining and the form chang'd . . yet , the parts of the substance , and the quantity it self with the substance against which 't is condivided , are not actually in their compounds , before division : for , 't is plain that , if they are in act , one of them , before division , is not another ; they are , therefore , many , nor can be divided , that is , made many . . out of what has been said , 't is evident , that this formall divisibility has not the true nature of divisibility , that is , 't is lesse then the divisibility of a magnitude into its parts : for , a magnitude is divided into parts , whereof every one exists after the division , by their proper existences ; but , one , at least of these parts exists no longer , and that which remains exists , not alone , but commonly with some other , instead of the part it has lost . lesson ii. of the formall parts of substance , in particular . . hence it follows that , because a change , according to the parts of the substance , changes the substance it self ; the parts are parts of the substance , as it is such : wherefore , neither part is a substance ; since a part cannot be the whole : but , to be a substance is , to have a nature capable of existence : therefore , neither part , separately , is , by its nature , capable of a being : and , any agent to give a being to either part , separately , must first change its nature , that it may be capable of being ; for , to exist , cannot agree to that , in which there is not a power of receiving existence . . and , after the same manner , must it be said of quantity and all other accidents , whose notion is wholy without , and not comprehended in the notion of substance ; and consequently , their notion is lesse fit and apt for existence . . you 'l say , if these things are true , it implyes a contradiction that any accident should exist out of its own subject ; the contrary whereof is a matter of faith. . 't is answer'd , ther 's neither authority nor demonstration , in theologie , which convinces that an accident may be preserv'd out of a subject ; as , 't is plain , to those that look more attentively into it . . but , on the contrary , 't is evident a whole cannot be , without its parts in potentiâ or power , therefore a substance cannot be without quantity , which is its parts in potentiâ ; nor can a magnitude be , without its quantity's having a determinate proportion to its substance , that is , without rarity and density ; again , rare and dense diversly mingled , import all the rest of corporeall qualityes : 't is evident , therefore , that accidents cannot be without a substance . . farther , 't is plain , the division of substance is into a pure power and a substantiall form , or , that which makes it be a substance : for , since , by the division of a substance into its parts , the substance is chang'd ; it must needs be , that the part which is lost gives the being a substance to the whole , since , that being withdrawn , the notion of substance is taken away ; and that the remaining part is a pure power ; for , since 't is a power to the notion that 's chang'd , and that is the first of all others , 't is clear , in the remaining part ther 's no notion , and therefore , that 't is a pure power or possibility . . whence , again , 't is clear , ther 's a greater unity of the parts of a substance , then of substance to quantity : since , quantity and substance are , intellectually , distinct ; but , of the matter and form of compounds , ther 's but one only notion together . . you 'l say , 't is impossible to conceive that matter , of it self , has no notion ; for , it would not be cognoscible . 't is answer'd ; since , to be capable of being something neither is , in that kind whereof 't is capable of being , nor yet is wholly estranged from that kind : so , that which is a capacity to the first kind , that is , to substance and being , neither has it that first notion , and yet 't is not altogether estranged from it ; but , 't is a certain degree to participate being it self , by the mediation of another . . now the ratio or notion in a thing is that , by which its nature is fitted to the understanding , or the understandablenesse of a thing , or the quiddity , the whatnesse and , consequently , that , whereby a thing is made to be : the form , therefore , primarily , is the cause , or the whereby the being is had . . whence , 't is evidenc'd , there cannot be more substantiall forms , in the same thing : nor subordinate ones ; because , since the first form gives the being , the second must needs be adventitious to what has a being , and not give it , but be an accident : nor coordinate ones ; since they have each their own notions and , consequently , constitute more beings . . 't is plain , too , that the matter has a being through the form , and cannot be sustain'd otherwise then by the form ; since , of it self , it has not a capacity to be. lesson iii. of the vnity and distinction of bodies in common . . it follows , from what has been said , that there is some plurality of forms in nature , before all division : for , since division is made , by the interposition of one body , between the sides or parts of another , there must necessarily be , before division , a body to be the divider and another that may be divided ; which , being they are not more then one , through any former division , ( since , this is suppos'd to be the first , ) this plurality must of necessity proceed out of the very nature and notion of the things . . and , since essence is nothing but that whereby a thing is ; such things must be , essentially , distinct : since , therefore , to divide belongs to dense , to be divided to rare ; those things that are naturally rare and dense must be essentially distinct . . since , therefore , such things are transmutable among themselves , and adequately divide the universe ; the matter of rare and dense things must be the same , and consequently , that of the whole universe . . the same is deduc'd out of the very notion of matter ; which , being a power to the notion of a thing , is also a power or possibility to the notion of one : since , therefore , a multitude consists but of unities ; before unity , neither distinction nor multitude can be understood : there can , therefore , be no multiplicity of matter ; wherefore , that of all nature is but one. . hence , then , those questions are superfluous , whether one form can be the same in divers matters ? and again , whether many forms in one matter ? since , if it be ask'd , of the proper unity of matter , that of all forms is the same ; if , of the individuall unity , that the matter attains by its conjunction with a form , as it does its very being . . from what has been said , 't is clear , that every body , that is , every compound of act and power is a magnitude : for , since ther 's but one possible first matter , and that subject to quantity ; the compounds of it , too , must of necessity be subject to quantity . . hence , again , it follows , that no body moves , unlesse , in some manner , it be chang'd first : for since a bulk excludes another out of its place , by this , that it intrudes it self into the other's place , because two cannot be together in the same place ; unlesse it become greater then its own place or leave it , it cannot exclude another : 't is manifest , therefore , that it must be altered first , according to one of these mutations , if it become a mover of another . . hence , again , 't is collected that a body is , essentially , an instrument : for , since a body has two properties , to be mov'd and to move ; and , to be mov'd appertains to it , out of its power and the notion of matter ; 't is clear , the essentiall notion of it is to be taken from its vertue of moving , by which it expresses act , and which follows the nature of a body in respect as it actually is : since , therefore ▪ a body does not move , but in as much as 't is mov'd ; clearly , according to its essentiall notion , 't is an instrument of its mover or applyer . . a body , therefore , is a thing in nature , or , a certain part of the vniverse ; provided by the authour of nature , to produce a certain determinate motion , when 't is apply'd . . whence , three notions , or manners of defining a naturall ens or thing , are discover'd : a metaphysicall one , which is deduc'd adequately under the notion of being , and 't is , a thing which has an existence spread into many potentiall parts , that is , a thing in or of such parts : a naturall or physicall one , which , by sensible qualities , expounds the notion of those parts and , consequently , of the thing : and lastly , a morall one , as it were , which collects the same from the end , that is , from the quality of its motion ; for , the metaphysicall notion , properly , regards only its capacity of existence . . and , he that has any one of these three notions , even by that , has all : for , the sensible qualities impart both a capacity of existence and a power for action . . whence , too , it appears , that one body can have but one primary operation : for , since the sensible qualities give both the power of working and the capacity of existence , and they , in the same part of matter , are the same ; either they conspire to one operation , or not : if not , neither will it be one body , but many : if they conspire , there is , then , one primary operation of such a body ; which could not be produc'd , either by another disposition , nor together with any other disposition then that . a naturall body , therefore , is that one thing whose operation is one. lesson iv. of the essentiall unity and distinction of the elements and mixt bodies . . since 't is said above , that ther 's but one possible substantiall matter , and quantity is known to be infinite in power ; the power of matter , too , to quantity must needs be infinite : since , therefore , actually , quantity is but finite ; the composit or compound must needs be , in some measure , dense . . and , if whole nature were uniform , it must be establisht in a certain degree of density and rarity , springing from the proportion of matter to this quantity : but , the speciall and particular bodies which are in the universe , as it is now framed , participate , out of this universall proportion , some more some lesse of density and rarity . . since , therefore , the notions of density and rarity are the first differences of magnitudes : those bodies , which first and least of all exceed the nature of body in common , will be distinguish't by these differences , that some exist in denser parts , others in rarer ; which , in our physicks , we have said , are the elements . . since , therefore , the operations of rare and dense bodies , as such , are to divide and be divided ; and this last is passion , out of which the essentiall notion is not deduc'd ; it comes to passe , that all the elements receive their differences , according to their power of dividing : and since , to divide is a kind of simple action ; they are distinguish't by no other differences then of more and lesse , that is , of velocity and slownesse . . among the elements , therefore , those which are fram'd by nature to divide more swiftly must be more perfect ; and those are they which are more subtile : wherefore , since the greatest force of dividing agrees to fire , that must be the noblest ; next to which must be aire , then water , then earth . . which last , though , by its bulk and density , it may seem more apt to divide , and has , as it were , in the first place , the nature of divisive : yet , by reason of the grossenesse of its parts , in naturall action , it can doe the very least of them all ; and consequently , 't is the vilest and most beggarly instrument . . it appears farther that , since a body is , essentially , an instrument for a determinate motion ; and there must needs be some least degree of rarity and density ; and the littlenesse in bulk hinders both the divisive power and divisibility : there may be suppos'd , in every element , parts so little , that , according to the order of the universe , they may neither have a capacity of dividing others , nor of being divided by others ; and so , there may not be in them the essentiall notion of an element , nor of any other naturall body . . again , since all bodies are conjoin'd ; it appears , that such minutest particles never exist , but in composition with others : nay , when ever two or more elements are joyn'd , it must needs be that their extremes may be suppos'd in so little a quantity , that one cannot operate without the other . . there must needs , therefore , in nature , out of the pure conjunction of the elements , be a notion of a certain body , whose parts cannot act at all separately , but , in conjunction they may : that is , some body essentially distinct from the elements , and yet , made out of their conjunction ; that is , a body whose essence is to be a mixtum or mixt body . . but , since , in bodies , universally , unity and magnitude are consider'd : 't is plain , the differences of those bodies are collected out of three respects ; the specificall difference of the elements , that is , the degrees of density and rarity ; the multitude of parts of the same notion ; and their bulk . . a mixtum , therefore , is a body of certain parts , of divers degrees of rarity and density , in a certain number and bulk compacted among themselves , ordain'd by nature for a determinate motion . moreover , 't is evident , that the qualities of the elements exist refracted and mutually abated in mixt bodies ; since , the very least must needs simply differ in degrees of rare and dense , and these degrees , by reason of the composition , must needs hinder one another . . and yet , that no substantiall form of any element is found in a mixtum : since , a form constitutes a thing , and a thing is ordain'd for motion ; but , motion is of the whole , not of the severall parts . . out of what has been said , 't is evident , that the operation of a mixtum is a certain division qualifi'd by the nature of the parts of the mixtum : which nature , the better 't is , that is , the more serviceable for the best works of nature , so much the nobler is the mixtum , essentially . . again , if the whole mixture of the elements be shut up into so little a part , that one part cannot , separated from another , have its proper effect ; then the mixtum is simply one and primely mixt : but , if the mixture be extended so amply , that many parts may act , asunder , according to the divers parts of the temperament ; then , 't is not a mixtum , but a demixtum or decompositum , that is , one made up of many mixtum's ; as we see in metalls and other mines , as coal , &c. where many mixtum's are joyn'd together , which are apt to be separated by fire or other artifice . lesson v. of the essence of animals , and of the soul. . but because , among mixtum's , some are solid and consistent , others fluid ; and of these , by the course of nature , the conditions and temperaments are different and , in some sort , opposite : there must , of necessity , out of the conjunction of these , rise a middle temper , which cannot but be fit for some certain motions . . and , because all things , with us here , are beset with heat ; the solid parts cannot be kept moist , that is , mixt throughly with actuall moisture , unlesse there be some continuall cause or fountain , out of which the moisture , so consumable and subject to be wasted by the power of heat , may be perpetually supply'd . . now , that fountain may be suppos'd within and intrinsecall to the mixtum , or else conjoyn'd , that is , in a body joyn'd to it : but , if it be this later way , 't is plain , that watred mixtum is not , of its mere self , constantly what it is , but through its situation or conjunction to another , from which , if it be separated , it perishes . . but , that which is watred the former way has , within it self , what is necessary to keep it still a constant instrument in nature , of that operation which 't is fram'd to undertake : and , consequently , it has one form , from that one operation 't is ordain'd to , and that one order of parts conform'd to such an operation . . and , because we find these in all and only animals : an animal is evidently counted to be one naturall thing having one form. . you 'l say , if the severall similary parts of an animal , subsisting in their proper forms , were connected ; they 'd have the same effect as they have now in the animal : ther 's no need , therefore , of the particular form of an animal . . 't is answer'd , ther 's no particular nature in any similary part of an animal , which is common to that part alive and dead , as if there could be some form , as it were , indifferent ; but , the nature of a living part is contrary to the nature of a dead part : now , naturall things are naturall parts of the world , unerringly flowing from the essentificall idea's ; and , therefore , they receive essentiall notions , according to the order they have in the universe . . but , because the parts of an animal are so fram'd , that one should water , that is , alter or move another ; 't is plain that , of necessity , they must be of severall conditions and figures : wherefore , the complex of them is an organicall bodie , having within it self life , that is , a power of moving it self ; and , its form is the act of such a body , that is , a soul. . but , since the notion of a soul requires that the parts of its subject , whose orm it is , be some movers others moved ; 't is clear , that it does not inform each of the parts , or , is not in every part , as 't is usually said , and as it happens in elementary forms ; but , that 't is only in the whole and , immediately , the form of the whole . . notwithstanding , the parts have not , therefore , partiall or particular forms : because they are not actually in the whole , nor have , actually , any nature by which they could subsist out of the whole ; as appears , in that , being but divided , they presently die . . hence , 't is collected , wherein consists the metaphysicall notion of an animal : viz. that , 't is a thing of many parts , order'd among themselves , as to action ; that is , whereof some are active upon others , and the rest are passive from them . . to which the morall definition adjoyn's , that 't is an instrument for action , that is , for that operation or motion to which they apply themselves ; such as is locall motion , which all participate . . and , the physicall definition considers that many mixtum's are contain'd in an animal , as also organicall parts , that is , parts woven and compos'd of many mixtum's ; and so conjoin'd , that the libertie of each is not taken away , but that they are active upon one another , as if they were distinct things . . and , since , from the presence of an object , an impression is made upon an animall ; whence it begins to act about that which is without , so as is convenient for the nature it self of the animall ; yet , this impression is , such as makes no sensible change in the animall : we apprehend the object to be in the animall , as neither perfecting nor hurting it , but indifferently , and purely as another thing ; and this we call knowing : and , that the animall operates out of it self , as it were , what is convenient for it , supposing this knowledge ; and this we call working out of knowledge . . again , because it appears , by our physicks , that the proper motions of an animall derive their origin from the heart , which directs the spirits into the nerves that are necessary for all kinds of motion ; and that this impulse is call'd passion ; moreover , that all passions depend and emerge from love and , in an animall rightly dispos'd , are subject and conformable to love : it follows , that its prime love , or , the prosecution of its chiefly beloved is that passion or motion or action , to which the fabrick and compagination of an animall is immediately order'd ; and consequently , that animals , by these , excell one another . . now , the prime pursuit of an animall is after food ; and food is what is conformable to the quality of a body , and preserves and causes a right disposition : since , therefore , an animall agrees with other bodies in being an instrument , to be apply'd by another , and an instrument is , in so much , more perfect , as it can perform , more easily and more efficaciously , more or more noble works ; that animall will be better then the rest , which is more easily applyable , and to more things : for commonly , the more noble operation consists of the more parts , and what 's apply'd more easily operates more efficaciously . . the food , therefore , of that animall is best , which renders it of a calm fancy and of an appetite the most indifferent ; which , commonly , follow one another : and , that animall is the best , which is primarily affected to such food . lesson vi. of the chief animal and the essentiall distinction of bodies . . out of what has been said , it may be convinc'd , if some animal can be apply'd to one or more determinate operations , and another to whatever , without any term or limitation ; this later kind has so great an eminency above the former , that they are not of the same order : wherefore , it will be the noblest , and something above the order of the rest . . 't is plain , too , that nothing greater can be imagin'd , in the notion of an animal ; no , nor of a body : for , if a bodie be an instrument applyable to a determinate action , an instrument to all extends to both the noblest and the most : wherefore , nothing can be conceiv'd higher in the notion either of a body or an animall . . since , therefore , in our physicks , it appears , that a man , even in his body , is provided to do any thing whatever ; 't is plain , that a man is the prime both of bodies and animals ; and something beyond them . . it appears out of what has been said , that there cannot be any other differences of bodies , which are not comprehended in the fore-mentioned . for , the elements , differing in rarity and density , divide body , precisely , as it speaks quantity united to substance : the nature of mixtum's , which consist in the number and proportion of rare and dense bodies , follows that divisibility of quantity , whereby bodies have number and proportion : and , the site and order of parts we chiefly see in animals , whose members can act one upon another : lastly , the infinitude of quantity shew's it self in man , in that he is ordinable , after a sort , to infinite things . . again , since quantity is divisibility into parts , those are distinct either in number , as it were , and site only ; and bodies divisible into such parts are the elements : or , they differ in nature ; and such are the parts of mixtum's : or , lastly , they are parts which , in the thing it self , are , as it were , certain things exercising their own proper operations ; such are the members of animals ; the complex of which , if it makes a body orderable to all possible action , it constitutes a man. . again , the division which a body makes is , either simply dividing more and lesse ; and , by this , the elements are distinguish't : or , 't is a modify'd division , by which certain bodies , with a certain qualification , are distinguish't ; and this is the proper division of mixt bodies , by which their so many effects are produc'd : or 't is an abstractive division , that is , which , of it self , has no effect , but is a way and instrument to another division ; and such is the motion of animals ; which , if it be in a certain determinate manner and number , constitutes the other animals , if indeterminately and with infinite variety , belongs to man. . and , that these differences are essentiall , appears from hence , that they , of themselves , divide and include the notion and end of a thing consisting of parts , that is , of body or bodily substance ; as cloven-footednesse includes pedality , and the being divided into three or four toes includes cloven-footednesse : for , no difference , of any of these above-mentioned kinds , can be understood without the notion of a thing consisting of parts ; nor , be apapply'd to any other common notion , unlesse accidentally . . nor , is it lesse apparent , that these essentiall differences are the very accidents , that is , the very complexion or clinging together of rare and dense parts : which is call'd substantiall or essentiall , in as much as it furnishes the body for its prime and chief operation ; and as , saving the order to the chief operation , 't is mutable , so far 't is some of the accidents : for , since the parts are not actually in a formall compound ; 't is clear , that whatever is in the compound cannot be this and that , severall and distinct things . . a transmutation , therefore , is accidentall only or more then accidentall , in as much as 't is greater or lesse , or , as it extends to severall notions . . hence , again , 't is evident , that genericall unity , though it be founded in nature ( as appears out of what has been said ) : yet 't is not truly any other then mentall ( that is , by being in the understanding ) as to the effect of unity ; though the similitude in which 't is founded be reall . . and that the ultimate essentiall unity , which they term specificall , and imagine common , is no other then the very individuall unity : for , since all difference consists of the collection of rare and dense , and all operation follows the same differences in the very instant of the birth or first being of every thing , when the individuation is determin'd ; it must needs be , that whatever accidents there are , in the thing once made , either fit or avert it from the primary operation , to which 't is ordain'd : since , therefore , every change in the form makes an essentiall difference , and all variety in respect of the primary operation is a change in the form , 't is plain that every accident concurs to an essentiall change ; and ( which was intended ) that numericall difference , which is the ultimate and compleat proportion of a thing to its operation , is essentiall . . wherefore , since , from the highest ratio or notion of a thing consisting of parts , one may descend , by numberlesse degrees , to whatever individuall ; genericall degrees will be without any known number , but the specificall will be no other then that of an individuum . lesson vii . of the mutation of the individuality in the severall kinds of bodies . . and , hence , 't is evident that , a thing being chang'd but accidentally , the individuality is not chang'd ; because that 's taken directly under the notion of thing or body ; which is the last that 's destroy'd in the thing , as 't is the last that 's made . . for , since change is made by locall motion , and that 's divisible without end ; if , upon every accidentall variation , the substance should be chang'd , substantiall transmutation would be continually successive , and would not subsist but in motion , that is , so , that one part would not be whilst another is ; and consequently , the notion of a substance would never be nor its being be indivisible ; nor would there be any thing by whose mediation accidents might subsist ; to conclude , there would be nothing in nature , the constancy and firmnesse of substance being once taken away . . among the elements 't is plain , the notion of the individuum is chang'd by mere division ; so that , any whatever least particle being taken away or added , the notion of the individuum is chang'd : but , the quality of rarity or density being chang'd , the notion of the individuum is not , therefore , altered . . for , since the mutation according to rarity and density is a continuall one , that is , divisible without end ; there would be an infinite succession of individuums : but , it appears to the considerer , that it happens not so in division ; whose motion though it be continuall , yet the being divided follows indivisibly . besides , if , both by division and change of rarity , the quidditative notion of an element should be varied , there would be no accidentall change in the elements . . of mixtums , the manner is partly the same , partly different : for , if a dissolution intervene between the heterogeneall parts which essentially constitute a mixtum , there will be a change , not of the individuum , but of the genericall notion ; but , if any parts of the same temperament be either added or taken away , the individuall notion is accounted chang'd . . but , the unity of an animal is not prejudic'd by the withdrawing of neither similary nor dissimilary parts ; but only of those , wherein the prime force of its instrumentality precisely consists : and , that being maim'd , it suffers a genericall change . . for , since the divisibility of the elements is , precisely , into the parts of a magnitude ; out of that division , by the course of nature , a variation in the substances must necessarily follow . . as also , since the composition of animals clearly aym's , by a certain way , at a certain end ; a substantiall variatio in them must only depend upon the change of the adequate complexion necessary to the end of the composition . . lastly , mixtums ; since their notion is constituted betwixt both these ; as 't is aggregated of similary parts and has a conformity with the elements , so far , it follows , they must be subject to their way of change ; but , as 't is compounded of dissimilar parts , yet cohering in proportion not order , so far 't is chang'd by the change of the proportion without any respect to the order . . you 'l object ; since every accident concurs to the designation of the substance ; upon any accident 's being chang'd , the ultimate substantiall difference must be altered : especially , since a substance is defin'd to be nothing but a certain resultance from accidents . . 't is answer'd , that , as , 't is evident , plurality is , so , nothing else but division ended , as , notwithstanding , not every part of the division changes unity , but only the figure : so , it happens in rarefaction , that 't is indeed the production of a new element , when 't is perfected ; yet , every part of rarefaction does not partially change the substance of an element . . now , rarefaction and condensation is perfected , when 't is become such , that the former degree cannot be restor'd to the thing that 's rarifi'd or condens'd , out of the precise nature of common causes ; but ther 's need of a speciall cause for this effect : for , 't is plain , that , otherwise , it is not , in respect of the world , a new thing or part ; since , by the very common constitution of the world , 't will return to its former nature . . much more , in the destruction of an animal , every alteration is , so , a way to its destruction , as , notwithstanding , every part does not partially change the very substance of the animal . . hence , 't is collected , how ther 's made an augmentation of the same numericall animal , through the whole course of its life ; and how , many of its members being cut off , the same still numericall animal remains : for , it being said , that the substantiall notion of an animal is to be rated from its prime passion , and that that is the love of food , that is , of preserving it self ; moreover , that an animal being once made , the identity is not chang'd , unlesse the quality of its first operation be chang'd , according to the order of nature ; it follows , that an animal is not chang'd substantially , as long as the love of preserving it self remains in it . . but , the cutting off of members , clearly , does not take away this disposition ; and , the change which is made by the digesting food into it self is mean't to continue the animal : 't is clear , therefore , neither of these destroy the bounds of nature , which , we have said , are the ends and determiners of substance ; & consequently , the nature of individuation remains firm . . now , why an animal , remaining the same in substance , should not be rarefi'd although more quantity come to it : the reason is plain ; because , the substance of an animal is , of it self , indifferent to many magnitudes , that is , to be lesse and bigger , and that which it receives is deriv'd to it by the destruction of other bodies ; so that materia prima ( which is a capacity of quantity ) has that comparison to the augmented animal , that is , is a capacity of as much quantity in the animal , as it was before in many things : whence , it comes to passe , that in the animal , the quantity and substance retain the same proportion to the standard or universall substance , which before they had to it in the animal and its food . . it appears , again , out of what has been said , how the suppositum may be said to have more in it then the nature ; though these are , indeed , one and the very same thing : for , the nature speaks the complexion of accidents , precisely as 't is a complexion ; and so makes an instrument of the operation intended by nature : and the notion of this is one and determind ; and ther 's nothing in it but essentially and formally . . but , the suppositum is the thing which the nature constitutes : whence , because it so explicates the nature , as that , besides , it includes confusedly other notions ; as also , because the nature is a complexion of many , the natures of every one must needs be conjoyn'd with this nature or substance : it comes to passe , that all the accidents , according to their particular natures , are in the suppositum ; and consequently , that there is more in the suppositum , then in the nature . lesson viii . of the proper action of the chief animal . . it appears , farther , that , since an animal is governd by passion ; and passion rises from goods or ills to nature , that is , those things which are conformable or dissonant to nature : man , if he be applyable to all things , that is , prompt to embrace any ill of nature , or fly any good ; must of necessity have such a faculty in him , that , in his brain , ills of nature greater then any such good may be joyn'd to the good which he is to eschue , and likewise greater goods to the ill he is to embrace ; that , so , he may , by the applyer , be impell'd to his destin'd actions . . these goods , therefore , with ills , and contrariwise , since they are not conjoyn'd in the things themselves , and yet must appear to him conjoyn'd , and this not by mistake but by the design of nature ; 't is plain , there is in the man a faculty whereby it may appear to him that those goods are conjoyn'd with the ills , and that he from that appearance is mov'd ; and not because the appearances are naturally conjoyn'd ( as , peradventure , 't is in beasts ) , which , not having any conjunction from a conjunction of the objects in nature , ( as , future or past things ) , cannot from such conjunction , that is , by force of nature , have a power of moving through conjunction . . and , since this conjunction moves a man , not as being a manner of the knowledge of things , but because 't is the thing known ; the other conditions , too , of things and chiefly their very existence must be , so , in a man and , so , move him : the objects , therefore , as existing , that is , existence as existence must be known by a man. . and , because existence , by its own form and its very being existence , excludes non-existence ; he that knows a thing exists knows that it does not not-exist , or ( which is as much ) that what exists , whilst it does so , cannot not-exist . man , therefore , has a foundation whereby he may be certify'd of all truth , viz. that the same cannot be and not-be , at once . . since , therefore , then we are judg'd to understand , when we know a thing is and cannot be otherwise ; a man , certainly , is to be call'd an vnderstanding creature . . again , since our knowledge rises from our senses , & our senses , sometimes , are so imperfectly mov'd by the objects , that , though we perceive ther 's something , yet we know not its quality , ( for example , we see a body , which we know not whether it be alive or dead ; or , we discern it moves it self , but doubt what kind of animal 't is ) : 't is evident , we know some one thing , of more like to one another which we are acquainted with , to be , without distinguishing the individuality , that is , we have an universall notion which is indifferent to many . . and , compounding these former with this farther consideration , that 't is the same thing to know one thing is another , & to know that those things , which are the same with a third , are the same between themselves : 't is plain that a man is discoursive ; and that his knowledge is deriv'd from those things , whereof he 's certain , to something , whereof he was not certain , but is rendred certain by the very derivation . . and because , of those things which are unknown , either part is indifferent to the understanding , and the understanding is undetermin'd concerning them : it follows , that a man , by this discourse , of undetermin'd , is rendred determin'd ; and , because the principles of determination are in himself , it comes to passe that a man determines himself and moves himself . . again , since , 't is clear , that one part of a man is affected from another part , as from a sensible object ; for example , one hand feels the other or whatever other exteriour part of the body ; in like manner , we are sensible of our selves by smell , hearing , and sight : it follows , that a man can think and discourse of himself and , consequently , of his actions ; and , by consequence , that he can determine himself to act or not-act , the understanding descending by discourse to the good or illnesse of the action he is about to doe . . a man , therefore , moves himself to act and is master of his action , and , out of the notion of good and ill , differently disposes his action ; which we use to call being free : a man , therefore , is free. . you 'l object , that liberty , according to the common notion of men , consists in this , that , supposing all things requisite for action , yet a man can , out of an intrinsecall faculty , immediately will to act or not-act . 't is answer'd , this is not the notion of the vulgar ; which holds to act and not-act for the notion of liberty , without that addition of supposing all things requisite besides the action it self : nor is it the notion of the learned , that have sought in nature it self , how the notion of the vulgar should be explicated . . but 't is an errour in metaphysick , in as much as it supposes an indifferent , as indifferent , to act ; and that to be in effect which never was in cause , that is , an effect to be without a cause . . again , 't is erroneous in morall science : for the notion of vertue would be taken away ; whose nature 't is to incline to will actually , so that , a more vertuous person is more determin'd to will just things then a lesse vertuous . . perswasion , too , and negotiation would be taken away : for , if the determination of the will should proceed not out of the preceding causes , in vain would be the endeavours of drawing men to follow one thing more then another . . out of what has been said , it may be determin'd , that man , by force of his intellective vertue , consider'd in it self , is capable of infinite science : for , since , whatever is added is still a degree and disposition in the man to farther science 't is apparent , the understanding is not burden'd but rendred more capable by former science : wherefore , since science , for its part , may , by addition , encrease without end , and is only restrain'd by uninfinitenesse of the number of the objects , it must needs be that man is capable of comprehending all , that is , infinite science , together and at once ; that is , he is of a capacity absolutely infinite , in respect of bodies ; comprehending infinite of them , as a superficies comprehends infinite lines , and a line infinite points . . again , since , among knowable things , those are contain'd , too , which are to be done by a man ; to this , also , humane science extends , even to know what 's to be done . and , since science is an active principle , a man , by science , will be enabled to direct his actions ; that is , to govern his life ; and this most perfectly , because he is enabled to know what 's best to be done . lesson ix . of the soul of the chief animal , or , of the mind . . out of what has been hitherto explicated , 't is easily deduc'd that man , according to this principle , is rais'd above the notions of matter and quantity . for , since matter is a certain capacity of quantity , quantity of figure , figure is determin'd by place , and all these in time : but , 't is clear , that the intention and thought of man , in an universall conception , is entertained about something indifferent to infinite figures , places , times , and magnitudes ; and this , not out of the nature of the thing , but because 't is in the mind of man : 't is most evident that the mind is something of another kind then matter and quantity ; and consequently , nobler , since 't is an addition to the perfectest bodies . . again , since thing and existence is that which first and primely fixes the mind , and to which it seems to be a certain capacity : but thing ( out of what has been said ) abstracts from and is before great and little , both in rarefy'd and augmented things : it follows , that the notion of the mind is before and nobler then quantity and , its com-part , matter . . again , since all the negotiation of our mind reduces divisibles to indivisibility ; as appears in numbers , figures , points , lines , superficies , instants , comparisons , denominations , relations , negations &c. but , nothing is so different as an indivisible from a divisible : 't is clear , on all sides , that the nature of the mind is wholy opposite to the nature of quantity ; and quantity implying a kind of undeterminatenesse and confusion , that the mind is still the nobler part . . nor , with lesse evidence , is it prov'd that the mind is a substantiall principle of man : for , since his operations are manifestly indivisible ; but , what is receiv'd in a divisible , ipso facto becomes divisible upon the division of the subject ; 't is clear , his operations are not receiv'd in a magnitude , and , consequently , that his mind is an indivisible substance . . again , if the substance of man be wholy materiall and divisible , his mind it self and all its affections can be nothing but certain manners and determinations of divisibility ( as , 't is plain , of the other qualities which are accessory to bodies ) : but , 't is plain , out of what has been said , that 't is no such thing : wherefore , neither that the whole substance of man is materiall , but , in part , spirituall and indivisible . . 't is clear , too , that the mind is not another , but the same substance with the man : for , since an instrument to all things includes the being an instrument to some ; wherein consists the notion of an animal : 't is clear , that a man is a certain species of animal ; and consequently , that his mind , by which he is a man , is formally one and the same thing with the rest of the substance of man. . and indeed , were it suppos'd a distinct thing from the substance of the man , it would not suffer from the body , nor could it acquire any thing through its conjunction to the body , nor be at all conjoyned to it : for , it must be either entitatively , and this cannot be otherwise then by unity of substance , for a thing speaks substance ; or , some other accidentall way , whereof ther 's nothing common to a body and a spirit . . you 'l say , since a spirit is a thing of another order then a body , how can it concurre into the same thing ? then , how will it be cemented ? and , what neighbourhood of one to the other ? 't is answered , that , as , in a magnitude , one part is fastned to another , and has the power of a subsister without division , that is , the propriety of a sever'd thing without separation : so , the soul also , may be the same with the body , without confusion of properties . . and , because , in a corporeall substance , ther 's admitted a certain negatively indivisible vertue antecedent to divisibility , viz. a not-yet divisibility of the substance before the quantity : such as is the connexion and gradation from the divisibility to the negative indivisibility ; another like that will be apt to unite , without a paradox , the mind positively indivisible , to the substance negatively indivisible . . and , how will it unite ? but , according to those parts , in which the substance primarily and principally resides : which , as 't is principally in the heart , that being a certain fountain of the whole thing ; so , specially , as to the notion of animality , 't is in the brain , whence sense and motion is deriv'd to the whole animal , which are those operations from which 't is denominated an animal . . since , therefore , the other actions , which do not affect the heart nor the brain , strike not home to the inmost substance ; so , neither do they reach mentall knowledge or the integrity of the soul : but , the changes that strike upon these principles affect the soul , too ; and , it comes to passe that not-the-same ordination of bodily parts , especially of the spirits and heart , follows in man from the brain 's being affected , which would follow in another animal ; but one , from the propriety of the affected substance , conformable to the whole , not to the body alone . . but , any other unity , then that the soul should intimely be comprehended in the definition of man , and consequently , should consist of the same notion and indistinct predicates , is not to be look'd for in substance . lesson x. of the proficiency and deficiency of man , and of his essence . . this , therefore , is out of controversie , that man , as to his soul , suffers from corporeall agents : for , since the soul it self is a certain affection or qualification of a divisible substance , which is introduc'd and expell'd by corporeall actions ; 't is clear , that those actions , which reach to the very substance , must , of necessity , affect and be receiv'd in it , after its manner . . consequently , it acquires science : for , since , 't is nothing but a certain possibility to science , as to its perfection ; 't is manifest , that all its change is towards science , viz. to be some kind of knowledge , either perfect or imperfect . . whence , even they , that deny the soul acquires science , say that 't is excited and admonish't by the presence of the body : but , to be excited and admonish't is to receive knowledge : the soul , therefore , acquires knowledge from the body . . nor makes against this socrates's experiment of a boy , orderly ask'd and answering right to geometricall propositions : for , this questioning was a production of science , not a renovation ; for 't was an application of the notion of the same being , which is between the terms , to the understanding of the boy ; whereby it came to passe that the truth to be known was by the notion of thing , knit to the soul of the boy , and made , as it were , a part of it , in which the vertue of knowledge and science consists . . yet , the soul has not , by this science , a power to move the body : for , we see , science is often overcome by passion ; but , if it had any proper activity , it could not be resisted by any power of its own body : moreover , it would no longer be a part of a man , but something grafted in him of a superiour nature , according to that vertue . . it follows , therefore , that , by vertue of the soul , more motives of goods or ills are conjoynd to the singular objects ; by whose conjunction the heart and the body is affected otherwise to those goods or ills , then it would be had they not that conjunction : so that , the force of pain and pleasure is that which moves a man , even then when he seems to follow the firmest reason ; namely , because to be reasonable to follow this and to fly that , is nothing else but that more of delightfull is conjoynd with this and more of painfull with that . . in vertue of these , therefore , a man is chang'd , and acts otherwise then if he had not understanding . nor , is he carry'd , from the very beginning , by reason or any proper power , to this connection of goods with ills ; but is prevented by some chance or obvious disposition of objects & corporeall causes , either intrinsecall or extrinsecall . . now , this disposition in the soul , upon which operation follows , we call the will , and the first beginning volition ; which , 't is apparent , is left by precedent judgements , chiefly those that are about good or ill , since , by such judgements , 't is plain , a man is determin'd to action . . hence , it appears , how the soul fails in opining : for , seeing objects occurre to the soul , not deduc'd and drawn-in , by its own force and nerves , as it were , but , by the agitation of bodies ; if the affection to any thing so presses a man to action , that it leaves not room for the objects to run in that order which is necessary for demonstration ; the man must needs fall to acting , before he has any absolute evidence what 's to be done . . if this be done by reflection , a man see 's that he 's mov'd uncertainly ; but , he see 's , too , that nature requires he should move upon apparences ; whence , he does no unbeseeming incongruous thing : but , if it be done without reflection , a man takes an uncertainfor a certain ; which is , to opine ; for he says , this is , which he has no determinate cause to say . . from this precipitation of action , it happens , that one man operates better , another worse ; according as one , more frequently or more grievously , precipitates his action , then another . and , those that come nearest to evidence , as far as nature will bear , doe the uttermost of their power ; which is to operate vertuously : but , those that very much recede from it , are call'd vitious : between which , a certain middle state of men inclines notoriously to neither part . . 't is clear , therefore , whence the defectibility of vice rises in man-kind : to wit , because , by too much precipitation of bodily motion , false or the worse opinions are generated . whence , it follows , that man is not only changeable from imperfect to perfect , but also from good to evil , and contrariwise : for , if he has opin'd a falsity , upon farther light , he may be led to the truth , and if , invited by apparences , he has follow'd the truth , by others he may be averted again . . whence , 't is evident , ther 's some opposition in the soul , that is , some acts incompossible at once in it : for , since those things which are in the soul inhere in it , in vertue of being ; 't is plain , it must be gather'd , out of the very notion of being , what things consist together in the soul and what not . now , 't is clear , that 't is against the notion of being , that the same should be and not-be : but , of those things that are , all agree in the notion of being , nor does any thing hinder that white and black , light and darknesse , hot and cold should coexist ; wherefore , neither does any thing forbid their being together in the soul : but , for the same to be and not-be , which is , to be affirm'd and deny'd , 't is wholy repugnant . . since , therefore , man suffers no repugnancy in himself to have whatever other things together in his mind ; it comes to passe , that he is capable and cognoscitive of all things : he can , therefore , know what 's best for himself , or , in what state he may most perfectly enjoy himself : nor , will he doubt that he is to strain towards this by all his actions ; wherefore , he will be govern'd against nature , if he be employ'd otherwise then is convenient to attain this last end. . whether , therefore , one man rules another , or whether some superiour power governs him ; he govern'd against nature , if he withdraw him from this chiefest good : and because nature is the principle of acting ; a man , as far as he is able , will reduce himself to a rectitude and straight course towards his ultimate good , and will resist all contrary operation . . though man , therefore , be an instrument , fram'd to be mov'd by another , as all other animals : yet , 't will be with this difference , that other animals are ordain'd to be mov'd to the end of the mover , without any respect to their proper good ; but , man is govern'd to the mover's end , no farther then as the same is a motion towards the proper good of man. . man , therefore , is an instrument , fram'd by nature apt for universality of action , that is , to do any thing whatever , so it be in order to his proper good : or , a thing , of connected parts , in a passive and active order , that is , which can order themselves : or , lastly , consisting of a rationall soul and an animal body . peripateticall institutions . fifth book . containing that part of metaphysick , which treats of substances abstracted from matter , and of the operation of things . lesson i. of the souls separation from the body . . out of what has been said , 't is evident , that a humane soul perishes not at the dissolution of its body : for , since , whilst it exists in the body , it has immanent acts which cannot belong to a body ; it must of necessity have , of its proper self , the vertue of a thing , or , of receiving existence : since , therefore , ther 's nothing farther requir'd to exist , in a thing already existing , but the having in it self a power of sustaining existence ; and , 't is plain , that , the body being taken away , this power is not withdrawn , ( since 't is in the soul , apart from and besides the body ) ; 't is evident that , by the dissolution of the body , the soul is not dissolv'd . . adde to this , that , since there is no other substantiall divisibility , but of form and matter ; and matter is not necessary to the souls existence ; ther 's no divisibility in the subject of existence , as existence is in the soul , by means whereof the soul can be alienated from being . . we see , too , that all mortality of bodies either proceeds from contrariety , or from the divisibility of a quantitative subject ; whereof , since neither is to be found in the soul separated , 't is plain , that 't is not subject to corruption . . you 'l object , if the soul in the body is capable of existence , 't is capable of action or of a motive power ; as quantitative parts , though they have a common existence , yet act upon one another . 't is answer'd , quantitative parts are accessory to and find the substance already perfect : but formall parts ( at least essentiall ones ) do not presuppose the substance establisht ; whence , the active power follows not any one , but all . . you 'l say , that existence , too , supposes all the parts of a thing , as 't is a thing : wherefore , neither will the soul be capable of existence in the body . 't is answer'd , that action belongs to the soul in the body as existence does : for , existence makes not the soul , while 't is in the body , to be a thing ; for that 's primely of the whole , and the whole man is the thing ; but it makes the soul to be that which may be a thing : so , also , 't is not absolutely a principle of acting , but 't is a principle by which action becomes other then 't would be without it ; and consequently , it has a being , whence action may be , but not whence ' t is . . it appears , again , that the soul separated is not , truly , the same thing with the soul in the body ; but is substantially chang'd . for , first 't was joyn'd substantially to the body and was one with it : but , 't is clear , that when , by division , more things are made of one , the thing divided is chang'd ; especially when the unity it self was substantiall , as in the present case ; since the soul adheres to the corporeall substance , not by quantity , but by identification . . again , the soul , now separated , is the immediate and adequate subject of its own existence : whereas , in the body , the man himself was the thing , and the soul only a part of the thing , or , whereby the thing was . yet , 't is the same thing , as to its notion and definition ; since it consists of those predicates it had in the body . . you 'l object , in the body , it had not a power of receiving existence in it self ; therefore , neither will it have out of the body : for a part and a thing are of an intirely different kind , and vastly distinct from one another . 't is answer'd , that , as , in the parts of a magnitude , 't is manifest , that they are neither things , nor only parts of a thing ; but something between , which is so a part , that it may be some kind of whole : so , it repugns not , that there should be something in formall parts which is , de facto , a part , and yet may be a whole ; and that should be a kind of middle thing , which has enough in it self to become a whole , yet should not actually be a whole : whence , when the soul is separated , there is not any thing added to it , to make it more capable of existence , but that is withdrawn from it , which hindred it from existing . . now , he that desires to frame to himself , in some sort , a notion of a separated soul ; let him ponder with himself that object which corresponds to the words man or animal , as such : which when he shall see , abstracts from place and time , and is a substance by the only necessity of the terms ; let him conceive the like of a separated soul. . then , let him attentively consider some self-evident and most naturall proposition : in which , when he shall have contemplated that the object is in the soul with its proper existence and , as it were , by it ; let him think a separated soul is a substance that is all other things , by the very connexion of existences . . lastly , when , in bodies , he shall observe that motion proceeds from the quality of the mover & a certain impulse ; and that this impulse is deriv'd again from another impulse , and so up even to that which is first mov'd , and beyond : let him imagine the soul is a kind of principle of such impulse ; whatsoever thing that must be . . what is said of the substance of the soul , undoubtedly must be understood , too , of its proper accidents ; for , since they depend only upon it , ( being something of it , nay even the very soul ) , and it would be more imperfect without them ; they must run the same fortune with it , unlesse some speciall reason interpose . . whatever things , therefore , were in the man , according to his soul , at the instant of his death , remain in the soul after separation : wherefore , all his resolutions or iudgements , whether speculative or practicall , shall remain in it ; where , since they cannot be without apprehensions , even they , too , shall remain : and , since all things , which are made to follow out of or have connexion with these , are in a separated soul , in vertue of these , its science must needs be extended to all those ; all such , therefore , which have once been in it and are not blotted out , after death all remain . . since , therefore , in a soul ther 's an infinite capacity ; and ther 's no opposition of apprehensions among themselves , nor any other opposition , but of contradiction , whereby the same is affirm'd to be and not-be : all the apprehensions , scrap'd up together in the whole life , and judgements unretracted must , of necessity , remain ; unlesse some speciall cause withstand . . the whole notion , therefore , of the past life , all the particular acquaintances of familiars and other individuums , all sciences and arts , attain'd in the life time , survive after death . lesson ii. of the science of a separated soul , and its unity vvith the soul. . but , all these things being so , now , in the soul , that time was , they were not ; 't is plain , they are so conjoyn'd to it , that ther 's no repugnancy it may be without them : wherefore , so there be a cause , they may be divid●d from it : some kind of divisibility , then , there is between the soul and the things in it . . not that which is between the parts of a magnitude ; since , here 's an indivisibility on both sides , whereas a magnitude is not made up of indivisibles . nor , that which is between matter and form ; since the soul , which is before , is able to preexist of it self ; and whatever things come into it supervene to a thing already existing . nor that which is between substance and quantity ; since quantity is in a thing , as somewhat of it ; but things known are in the knower as other things which preexist out of him . . 't is , therefore , a speciall manner of divisibility which is not exactly found in bodies : for , since a body essentially includes a power or possibility , the unity of a body is by the privation of act on one side ; whence follows the unity of act in the compound : but , a separated soul is compos'd only of act or quiddity , as white or hot , and existence or being , as when we say , 't is : whence , its unity to another actually existing must be , so , as an act can be joyn'd to an act , that is , by identification or a community of being : and , after this manner , are in a separated soul whatever are in it . . whence , first , this is evident , that a separated soul knows it self : for , since , to be in another , by way of knowing , is distinguish't , in this , from the other manners of inexisting ; that , in others , what inexists is now no thing in it self , but that 's in which it is ; things know'n , by inexisting , lose not the being what they were , though they acquire the being of that which they were not : for , heat , in that which is hot , is something of the subject , nor has any proper being of its own ; but , the hot subject which is felt is , so , in him that 's sensible of it , that he knows 't is hot ; therefore , this subject to be actually hot is in the person that 's sensible of it . . in like manner , the soul exists substantially , because being is made something of the soul. again , this , that the soul is , is in the soul : for , since the soul is a certain power of being all things that exist ; and it self also exists ; it cannot but , by reason of its intimate conjunction , be present to it self according to this its power , which is that it cannot but be understood . . again , since all those things are in the soul which we have , above , recounted ; they must needs be , too , all known in the soul : and , because , 't is clear , that , in a syllogism , the conclusion is nothing but the very premisses ; all is known by a separated soul , which is deducible out of those things that are in the soul. . and , because , such is the connexion of truths , that , out of any one , all others , may , by links , be drawn in ; it comes to passe that a soul , which knows any whatever sensible truth , knows intirely all cognoscible things ; that is , every soul penetrates absolutely all things . . for , if any infant never knew its own being , it is not to be esteem'd to have arriv'd at all to the nature of man : for , since , even in us , to be sensible of or to know is by suffering from another ; we know another thing is , because we know we have suffered from it : but , if we know we have suffered from it , we already know we are : the first knowledge , therefore , even in the body , includes the knowledge of our selves . . and , since passion is a participation of the thing from which we suffer ; it must needs be that the thing is in us , when we are sensible of it : and , because it does not denominate according to its own proper appellation , but according to the quality of that wherein it is , ( for , we do not call an eye white or wooden , but a seeer of white or wood ) ; it must needs be that 't is in it , as another thing , and as of the nature of the sensitive subject . now , the reason why in the body , too , the soul does not know it self , but the man , a part of whom it is , is because 't is he that is and not it , as has been said . . you 'l object , this multiplicity of knowledge is fram'd or aggregated , either of severall knots and articles , as it were , so that whatever was knowable in this world by new discourse , the same is , in some sort , a new addition in the soul ; or of one simple knowledge which , eminently and in one formality , in a manner , comprehends all these knowledges : but , neither of these seems possible ; not the first , because 't would be a certain infinity , either in act , which is impossible , or in power , and then 't would be some continuity and a principle of continuall motion ; nor the later , for such an universality seems not to have any thing above it . . 't is answer'd , the manner of a separated soul , in some sort , contains both ; though 't is neither way formally : for , since , the parts in formall composition are not actually ; 't is plain , that neither can there be , in this composition of the knowledge of a separated soul , formall knots and articles of discourse , & consequently , no actuall infinity : again , since one part is not beyond another , that is , extended , as in quantity , but all , by a certain identificaon , grow together ; there can be no continuity between , though the parts be in power , that is , only in the possibility of the subject . . besides , that this power is not such that there should be any correspondent naturall cause to reduce it into act : but , 't is only a certain defectibility of act , upon which ther 's no active power but only a logicall or a creative one , which will never act . . 't is , therefore , a certain actuall metaphysicall composition , in which there is a logicall possibility that any of these later known things may be away , without hurting those that were known before ; yet so , that it can never come to passe it should be reduc'd into act : wherefore , 't is neither the precise contemplation of one formality precontaining infinite ; nor yet any actuall infinity , or naturall divisibility . . but , it may be compar'd to the metaphysicall composition of degrees ; in which we see peter or bucephalus so agree with infinite things or animals , that it contracts thence no multiplicity , and yet we may alwaies frame some new apprehension of them in our mind . lesson iii. of the eminency of a separated souls acts , above those it exercises in the body . . out of what has been said , it may be evidenc'd , that simple intuition or the inexistence of a thing in the soul serv's , in stead of that composition which is found , here , in our judgements . . it appears , also , that an actuall universall intuition of things supplses , abundantly , any need of discourse . . 't is plain , too , that , with that , ther 's no want of memory or remembrance ; ther 's no need of ordering or framing idea's ; and lastly , whatever the soul operates , here , by distinct acts and in time , there , together and with one only labour , ( not so much , is wrought out , as ) exists . . again , whereas , by reslexion , those things we have , in the body , thought on , we farther know that we have thought on them ; so that we can never know the last reflection , though we had infinite : a separated soul , by the simple inexistence of it self in it self , necessarily see 's all its knowledge without any reflection . . again , 't is plain , that a separated soul , in another manner , excells place and time , then in the body : since , in that , it only abstracts from them , but , out of that , it comprehends them . for , this universall and actuall knowledge places all place and all time within the soul ; so that it can act in every place at once and together ( as far as concerns this respect ) , and provide for all time ; wherefore , 't is , in a manner , a maker and governour of time and place . . it appears , moreover , that 't is active , out of its very self : for , since it comprehends all things , it needs not sense , as in the body , to perceive that infinity of individuality ; but it know's , even , to the utmost divisibility of magnitude , whatever circumstances are requir'd to action : it knows , too , what is good for it self ; whence , it , naturally & of it self , has both power and an actuall will , which alone are requir'd to act ; for power depends on pure science , and whoever is impotent is ignorant what is to be done , by him , to produce such an effect . . hence , lastly , it follows , that the proportion of pleasure and grief , out of the body , is infinite , to that in the body : for , since pleasure is nothing else , but a judgement concerning a good possest , out of which follows an activity to enjoy and retain it ; and grief is the same , concerning an ill , which the soul desires to repell : whether we contemplate the manner of the souls being , to which its acts are proportion'd ; 't is of a superiour notion , that is , of an infinite eminency . . or , the firmnesse and evidence of its knowledge ; since all knowledge receives strength from antecedents and consequents , it must of necessity attain an infinite excellency : for every knowledge of a separated soul has infinite things connected with it , out of which 't is confirm'd . . or , its eminency above time and place ; 't is rays'd in a like degree : or , lastly , its force of activity ; 't is beyond all comparison . wherefore , to the least , either pleasure or grief , of the future life , even abstracting from the perpetuity , nothing can be comparable in this mortall state , or considerable in respect of it . . again , 't is collected , out of what has been said , that all separated souls , or , at least , the most part are improv'd in this , that whatever false judgements they have taken up in the whole course of their lives , they throw them off by separation : for , since , the excellency of a separated soul is immense above the powers of an imbody'd one , & the connection of all truths is , immediately upon the separation , imprinted in it ; it must needs be that a true judgement of all things is impress'd : since , therefore , contradictories cannot consist together in the soul , the false judgements must be expell'd ; and souls , as to this , be universally improv'd . . nor , is it lesse evident that , among souls , there will be some difference , by reason of the employments they have follow'd in their life time : for , since , whilst we live in the body , one exercises his understanding more about one thing , another about another ; and , as , the first act works a knowledge of the thing , so , the following acts cannot but encrease this knowledge and more perfectly impresse it upon the soul : it follows , since all these must needs participate of the elevation caus'd by the separation ; the soul must know more perfectly , too , in separation , its accustomed objects and whatever depend on them , in a due proportion , then other things ; whence , it comes to passe , that the sciences here acquir'd , not only , remain in the future life , but , are in the same proportion , there , as they were , here . lesson iv. of the felicity and infelicity of separated souls , and their immutability . . and , because the affections in the soul are nothing else but judgements , upon which operation does or is apt to follow ; and the stronger the judgement is , so much the apter operation is to follow out of it , if it be a judgement concerning good or ill : it comes to passe , that our affections to our acquaintance and friends , and the rest which we have cultivated in this life , shall remain in the future : wherefore , we shall both better know and more rejoyce in our parents and friends , then in others , ( other circumstances alike ) . . and , because the affections shall remain , & that , in the proportion they were in , during life : it follows , that those who have , in this life , delighted in those things & sciences , which the soul is apt and fit to enjoy in separation , ( for example , in naturall contemplation , or that of abstracted spirits , especially , if with great affection ) , will have a vast pleasure in the state of separation , through the perfection of the knowledge they 'l enjoy . . but , those that have given themselves up wholly to corporeall pleasures will be affected with vast grief , through the impossibility of those pleasures , there . . you 'l object , that separated souls will see the unworthinesse of such pleasures , and consequently , will correct in themselves such erroneous and false judgements , nor will have such appetites as would torment them . 't is answer'd , these griefs follow not out of false , but inordinate judgements ; for , 't is true , that such like pleasures are a good of the body and of the man ( whose appetite is the appetite of the soul ) ; again , supposing the deordination of the soul , 't is true , that these pleasures are conformable and good , even to it : but grief follows , hence , that the judgements or affections about these are greater , then in proportion to those other desires , which ought to be preferr'd before them . . whence , it comes to passe , that the soul 's seeing these objects to be unworthy and not regardable , in comparison of the better , increases its pains ; whilst it can neither cease to desire those it desires , through the excesse of these affections above the rest , and yet sees they are vile and unworthy . . moreover , out of what has been said , 't is deduc'd , that , in the state of separation , no variety can happen to souls , from a body , or the change of bodies : for , since a change passes not from any body into the soul , but through the identification of the soul with its own body ; and this identification ceases , by the state of separation ; it follows , that no action nor mutation can be derived from any body , to the soul. . nor , has the soul , of it self , a principle of changing it self : not from hence only , because an indivisible cannot act upon it self : but also , because , since a mutation of the soul cannot be any other , then , either according to the understanding or will ; but the understanding is suppos'd to know all things together and for-ever , whence , by the course of nature , ther 's no room left either for ignorance or new science ; and the will is either not distinct from the understanding or , at least , is adequately govern'd , in the state of separation : it follows , that naturally no mutation can happen to a separated soul from within , or caus'd by it self . . nor , yet , from any other spirit , without the interposition of the body : for , since all spirits are indivisible , their operations , too , will be such ; but an indivisible effect , supposing all the causes , of necessity exists in the same instant : wherefore , if any thing be to be done between spirits , 't is all , in one instant , so done and perfected , that , afterwards , another action cannot be begun : for if it begin , either the causes were , before , adequately put , or not ; if they were , the effect was put ; if they were not , some of the causes is chang'd that it may now begin to act , and not this , but the former , is the first mutation , whereof , 't is to be urg'd , whether the causes were put before ? . if you say , the spirit waits a certain time : first , time is motion and not without a body : then , since , among spirits , nothing is chang'd by time , one that acts according to reason could not expect a time by which nothing could be chang'd . certain , therefore , it is , that there can be no change , by the power of nature in a separated soul. . from the collection of all has been said concerning the soul , 't is deducible , that our life is a mould or a march to our eternity ; and , according as a man behaves himself in this life , such an eternity he shall , hereafter , possess : since good-deeds and rewards , crimes and punishments are equally eternall . . to conclude , he that has liv'd perfectly shall be perfect in the future life , he that has liv'd better shall be better , he that has liv'd well shall be well ; he that has liv'd ill shall be ill , he that has liv'd worse shall be worse , they that live worst they , too , shall be worst of all for ever : so true it is that things will not be ill govern'd , that is , their very nature exacts and forces them into a good government . lesson v. of the nature of existence , and its vnity vvith the thing . . out of what has been said , 't is clear , that all bodies and a separated soul it self , sometimes , are and , time was , they were not : whence , 't is evident , that the notion of being or existence is different from the notion of that thing whereof 't is affirm'd ; since , 't is deny'd , too , of it , and since , of all substances that are so different , 't is said , according to the same notion , that they are . . besides , if , for peter or a man not to be , were the same , with peter not to be peter or a man not to be a man ; 't were a proposition destructive of it self , and , consequently , impossible ; but now 't is prudent and pertinent to sciences . . neither would there any one and the same thing be a subject of contradictory enunciations , or of affirmation and negation ; and consequently , the art of logick and the foundation of all humane discourse would be taken away : nothing , therefore , is more evident then that existence is distinguisht , mentally or by definition , from the thing whereof 't is spoken . . but yet , that it should differ , really , actually and , as it were , numerically or in the subject , from the thing whose 't is , 't is equally impossible : since , so , they would either of them be things ; the whole , therefore , would not be one and a thing , as above , in the like case , is deduc'd . . notwithstanding , since a thing really acquires and loses existence , ( for , to be made is to receive , to be dissolv'd is to lose existence ) ; 't is evident , ther 's a reall divisibility between a thing and existence . . but , this divisibility is lesse then any of those , hitherto , explicated : both because , in separation , neither part of the compound remains ; as also , because existence out of a compound is not intelligible , since 't is its ultimate actuality or actuation . and , as 't is commonly said , that union cannot be understood out of composition , nor action without a term ; so , neither can being without it actually be , and consequently , make those things be which are by it . . lastly , 't is evident , that existence is the perfection of every and all things ; since , the notion of all substances ( as 't is explicated above ) is nothing else but to be such a capacity of existing : whence , they have the notion of a power to that ; or rather , the notion of an as-it-were ( a quasi - ) possibility , since they have a vertue terminative of the understanding ( that we call to be a quiddity ) which a possibility has not . . notwithstanding , because this notion is nothing else , but a disposition and preparation to existing ; existence is not only the perfection , but , if it were perfect , it would be the whole perfection of any thing whose it were . . it follows out of what has been said , that no thing , of those that sometime are sometime are not , is of it self ; but , all require some other thing to make them exist : for , since they are sometime and sometimes are not , 't is evident , the notion in them , which is presuppos'd to being , and whereof 't is said it is , is , of it self , indifferent to being and not-being ; and , which follows , this notion being put , being is not put or the thing is not , in force of this notion ; and something else , therefore , is requir'd , which being put , being must necessarily be apply'd to that notion : 't is from without , therefore , that these things exist , and not from their own intrinsecall nature and force . . and , because this notion has not its indifferency from otherwhere , but from it self ; as long as it has being , so long an extrinsecall cause must make it exist : for , since its necessity of existing is from something without , that extrinsecall being taken away , it is no longer : and , because from an indifferent nothing follows , its exexisting is not deriv'd from any intrinsecall ; and , which follows , if , the extrinsecall being taken away , it should exist , this , its existing , would be an effect without a cause . lesson vi. of the existence , simplicity , and eternity of god. . again , it follows , there is some thing , for whom 't is impossible not to exist : for , since an effect is because another is , 't is clear , the same cannot be the cause of it self : nay , if two should be put , as , adequately , cause and effect to one another , the same would be put as cause of it self ; for , if a be because b is , and b again because a is , 't is clear , that a is because a is , that is , 't is cause and effect to it self . . wherefore , since those things that may not-be need an extrinsecall cause to be ; nor can all things have an extrinsecall cause , unlesse some two be , reciprocally , causes to one another : it follows , there must be something which needs not an extrinsecall cause ; and consequently , must have , from its intrinsecalls , that it cannot not-be , and for which it must be impossible not to be. . again , since an impossibility of not-existing imports and carryes existence along with it ; and this impossibility is intrinsecall and essentiall to the thing in which it is ; it follows , too , that existence is essentiall to such a thing . . and , since existence is equally universall with the notion of being or thing , that is , every thing has an existence correspondent to it , which it may actually have ; and being is the most universall predicate of that wherein 't is ; it follows , that existence is the most universall predicate of the thing to which 't is essentiall . . but , on the other side , because existence being put , the thing is compleat , as to its essence ; nor can any essentiall predicate supervene to that which exists , but all are presuppos'd to existence : 't is clear , that , to the most genericall notion of a thing to which existence is essentiall , there can no essentiall difference supervene ; and consequently , that , between things to which existence is essentiall , there can be no essentiall difference , that is , but one only such thing can exist . . there is , therefore , some thing essentially existing of it self ; from which , being but one only , all other things must , of necessity , receive their birth and existence : now , such a thing we conceive to be that we call god : there is therefore , a god. . the notion , therefore , of god's existing is , that his existence or essence is diametrically and contradictorily oppos'd to not-being : not , in the understanding , as a chimaera is oppos'd to a non-chimaera ; nor , in possibility , as a man to not-a-man ; nor , in an irradiate act , as it were , and impress'd like a seal in water , as our being and not-being , running and not-running : but , in the thing it self , by the highest and ultimate actuality , substantially , by the very essence of being and exercising , by the very notion of existing , it self substantially and concentrally within it self and about it self and upon it self reflected , exercised , and exercising . . this is the solidity and stability of the first thing and god ; whilst , the stability of all the rest is no other , but to depend and be from him. . out of what has been said , is deduc'd the most eminent simplicity and indivisibility of god. for , since existence is essentiall to him ; and there can be nothing in a thing , neither before nor after existence ; 't is clear , that god is so existence , that he is nothing besides , formally . . therefore , he is not corporeall or compos'd of parts excluding one another : for , a body , since it has a being in parts , of necessity includes something besides existence , divisible from that . . the same is for composition of matter and form , subject and accidents ; for these , since they include something divisible from being , cannot be pure existers . . nor is there any room for composition of genus and differentia ; since , difference supervenes to a genus , at least , with a foundation in the object for so apprehending it . ther 's , therefore , absolutely , no composition at all in god. . but , whatever composition there is in our understanding concerning god , proceeds out of the pure defect of our understanding , which cannot adequate the simplicity of the divine essence . god , therefore , is pure being , pure actuality , the pure brightnesse of eternall light. . again , hence 't is deduc'd that god is eternall , or , that there is not in god past and future , but only present . for , since god cannot not-be , by reason of the essentiall exercise of his being ; and , has this essentially , that he cannot not-have-been nor not-be-to-be , but possesses his essence indivisibly : it comes to passe , that 't is the same thing to god not to-not-have-been and not not-to-be , as to be what he is ; but , there cannot be , either by imagination or in time , an instant suppos'd , in which god possesses not his essence ; in every moment , therefore , of time whether reall or imaginary , he is his not not-to-have-been and his not not-to-be hereafter , that is , his to-have-been and his to-be . . in every instant of time , therefore , he is in every instant of time past and future : not , that the time past and future are ; but , that the indivisible existence of god possesses all that length , which passing times make , contracted ▪ by the eminency of his simplicity , in an indivisible act ; and never either loses or gains , because his repugnancy to not-being is actuall being , and actually-to-be is his essence . lesson vii . of the perfection , immutability , and science of god. . farther , the perfection and plenitude of god is deduc'd , that is , whatever goodnesse and perfection is possible , all this is eminently found in god. for , since existence cannot receive existence from another , but is by its own force ; 't is plain , that whatever existence is and whatever perfection is in existence has its being from that power ▪ by which existence exists : the whole perfection , therefore , of existence is in that existence which is of it self and by its own notion ; but this existence is , as has been said , the very essence of god ; wherefore , in god , there is all the perfection which ist in existence or can be in it . . since , therefore , whatever is in any thing , besides existence , is nothing else but a disposition to existence , or a capacity of it , or a compart in which and by which imperfect existence is to subsist : 't is clear , too , that perfect existence subsisting includes , more eminently and perfectly , all this perfection , and consequently , that all the plenitude of being is in god. . besides , since god or being-of-it-self is but one alone ; whatever is besides must , of necessity , receive beginning , goodnesse or perfection from him : but , that the adequate cause contains all the perfection of its effect is , of it self , evident : all that ample and inexhaustible plenitude , therefore , of intire being is in god and flows from him. . out of these foresaid attributes of god , his immutability is demonstrated : for , from this plenitude of perfection , he is immutable ; because he can neither acquire nor lose any thing . . from his simplicity , again , he is immutable ; because all mutation includes ▪ a divisibility of that which is chang'd , from that according to which it is chang'd . . and lastly , from his eternity , he is immutable ; because what is chang'd has sometime and sometime has-not the same thing ; but , what god has he has indivisibly for ever , and , in that very respect , he cannot not-have it . . out of the premisses , too , 't is collected , that god knows & understands both himself and all other things , by his one only essentiall act of being . for , since god is existence it self & the plenitude of being , nothing can belong to existence which is not primarily in him : since , therefore , to know , is to have the thing known , after a certain proper manner of existing , in one's self ; god cannot not-be in himself , after this manner of existing , that is , not-be-known by himself . . again , since all other things are in god ; but , to inexist as another thing , is a perfecter manner of inexisting then simply to inexist ; it appears , that all other things in god inexist after this manner , too , that is , are known . . nor , does this any thing prejudice the divine simplicity : for , since those things that are known inexist as another thing , the bounds and divisions of the creatures in god are as other things , and produce not their effect , viz. of distinguishing , in him ; but , their being in him has nothing whereby one should be oppos'd to another ; as appears even in us , in whom two contraries inexist together , that the one may be known by the other . . it appears , too , that god knows other things , in his own essence : which , since it may doubly be understood ; one way , that his essence should be the principle of the knowledge of other things ; and another way , that the knowledge of the creatures should be , as it were , a part of the knowledge of his essence : 't is to be taken this second way . . for , since the essence of god is not from another , but by its own formall power of existing ; 't is plain , its manner of existing is opposite to the being from another : there ought not , therefore , to be put any vertuall causality , whereby one should be from another in god ; because , whatever is in him is because it is , or by vertue of self-being . . you 'l say , the creatures are something distinct and another thing from god ; wherefore , the knowledge of them , too , is distinct from the knowledge of god. 't is answer'd , by denying the consequence : for , some distinct things are of that condition , that the knowledge of one is part of the knowledge of another ; and so it happens in the present case . . for , since god cannot know his essence , unlesse he know his science and the , as it were-vertuall parts of his essence ; and , since the creatures flow immediately from god , without any other help ; it comes to passe , that god is a cause actually causing by his essence : 't is plain , therefore , that part of the knowledge of the essence of god is , to know that he actually causes such creatures , which includes , that such creatures exist : part , therefore , of the knowledge of the divine essence is to know the creatures exist , in all their differences and circumstances . . again , the universall answer is evident to all those questions , whether god knows future contingents ? the secrets of hearts ? infinite things ? materia prima ? negations ? mentall or imaginary things ? &c. . for , 't is evident , as far as these are apt to exist and to be known , so far they proceed from god ; and the knowledge of them is part of the knowledge of god : but if , on any side , they have no entity nor cognoscibility , so far they are not known by god : but , to enquire , of each of them , what cognoscibility they may have , belongs to their proper places , not to this of the science of god. lesson viii . of the divine volition and liberty . . nor is it lesse evident , out of what has been said , that , since god , operating by existence , of necessity applyes himself to the particularities of the creatures , ( since particulars only can exist ) ; and more things cannot be in one but by science ; that , i say , he makes the creatures by his science : wherefore , since science , when 't is so perfect as to be able to proceed into action , is call'd will ; 't is clear , that there is a will in god. . and , since the science of god is every way perfect , it appears , by the same evidence , that there is all the perfection of will in god , or , all morall vertues , as far as they follow out of pure perfection . he is , therefore , gracious , iust , mercifull , patient , and whatever other use to be pronounc'd of him ; out of the eminent perfection of his essence , as 't is call'd science . . and , since liberty is among the perfections of will , by which the will or the person that knows chuses one out of many , according to the principles of his proper nature ; and , the science of god is larger and more ample then his operation ; nor is there any thing , out of himself , by which he can be impell'd to operate this more then that ; 't is clear , that god , freely and according to his innate inclination , chuses and operates this rather then that . . you 'l object , since god is a pure act , there cannot be put in god a naturall inclination , according to which election may be made ; because it would have the notion of a principle in respect of the act of election : there cannot , therefore , be put liberty in god. 't is answer'd , there cannot be put , in god , election in fieri , or , to-be-made , but only in facto esse , or , already made , that is , such a will as is election already in act ; and to this there is not requir'd the notion of cause and effect . . moreover , naturall inclination , as 't is put in god , is not any active principle , but a certain common and abstracted notion by which we know god ; and , to which , that more particular notion is conformable , according to which we attribute the name of election to god : as , for example , to this volition , by which god will 's that which is best , the volition of the world's creation is conformable , by which is chosen the best in particular . . you 'l object , again , since god essentially has all vertues , he alwaies does , of necessity , that which is best ; and would doe against his own essence , should he doe any thing otherwise then he does : 't is , therefore , determin'd to him essentially , to doe every thing as he does : but , that which proceeds out of nature and essence is not free : god , therefore , does nothing freely . . 't is answer'd , even in us , after we see any thing to be better , 't is against nature to doe the contrary : neither are we free , because we can decede from nature ; for , so , liberty would not be a perfection but an imperfection , since all perfection is according to nature : but , liberty consists in this , that , among many , which , at the beginning , seem indifferent , we can find which is more according to nature ; and embrace that , because 't is conformable to naure . . therefore , in god , too , liberty is , so , to be put , that it be understood he has arriv'd , by his science and understanding , to act what is conformable to his nature : and though , after he 's suppos'd to have arriv'd to that , 't is against his essence to doe another thing or not to doe this ; yet , his liberty is not , thence , diminisht : as , there is not lesse liberty in a constant man , that changes not his judgement once establisht , then in a fool , that , at every little appearance of reason , alters his opinion , but a greater ; for , a constant man , therefore , changes not , because he alwaies exercises his wisely-made choice , that is , the better , whereas a light person exercises now the worse , now the better . . again , for the most part , those things that are-not-chosen are not against the nature of the chooser , in themselves , but from some accident or complex of circumstances ; whence , the terms precisely consider'd , the chooser may doe them according to nature , but , because of some circumstance , he cannot : and , even thus , liberty may be attributed to god ; for , to doe some particular thing , which he does not , is not against the nature of god precisely compar'd to this thing ; but , when the other circumstances are collected , it appears another thing is better , and then 't is against the nature of god to doe this : yet , this prejudices not his liberty ; which consists in this , that he rejects that which , in it self , is according to his nature , because , by accident , 't is against it ; which we experience in our selves to be the track and path of liberty . . you 'l say , that god is determin'd by the very being of his essence ; and , so in him can be understood no indifferency to the utmost circumstance . 't is answer'd , this hinders not but that we are necessitated to conceive that perfectly-determin'd essence , by divers abstractive notions ; in one of which this determination is not , so precisely and by design , exprest as in another ; and so , to us , the more particular of them becomes the determination of the more common ; and of both is compounded the notion of liberty exercis'd in god. . you 'l object , thirdly , if god were free , he could not-doe what he does ; therefore , 't were possible for him not to have the volition and science which he has ; 't is possible , therefore , there should not-be the same god. 't is answer'd , by granting god can make that which he does not ; but , by denying the consequence , that he could have another volition then he has : for , when we say , god can make another thing then he does , we compound the power of god or his fecundity with the object whereof we speak ; but , when we speak of his volition , we speak of his vnderstanding compleated to action , and this proceeds to action upon the consideration of all accidents , out of which , as 't is said , it happens that this object is not made , because 't is not-best and against nature . . 't is , therefore , to be deny'd that there can be in god another act of volition , or , that his will is indifferent to this and another act ; though his effective power , taken abstractedly , is indifferent to more , because it respects the only notion of being , or , thing , in them : and thus , 't is evident , how there is not , thence , inferr'd any possible mutability in god. . you 'l say , his will , abstractedly taken , is indifferent , too , to more acts . 't is answer'd , we speak not of the will as it means the faculty , to be abstracted in god ; but of the will as it signifies the act or volition ; and that alwaies imports that the last determination is made , though it expresses not what 't is : whence , the notion of it is different from his omnipotency , which , because 't is referr'd to things without , does not of necessity imply the second act . lesson ix . of the divine names , hovv they are improperly spoken of god. . out of what has been said , hitherto , of god , we find farther , that the names which we attribute to god are all imperfect , and , not one of them all has any notion whose formall object is in god. for , since god is a most simple entity , precontaining in one most simple formality , the whole plenitude of being , that is , the objects of all our notions & the significations of all our names : . and is , too , existence subsisting ; but we have but one only name and notion of existence , which signifies nothing besides : 't is clear , that our names do infinitely come short of the most simple essence of god ; both in their genericall notion , because god is in none of our predicaments ; in their integrity , because no name of ours represents all that is in god ; and in their form , because none of our apprehensions have a formall likenesse in god. whatever , therefore , we pronounce of god , must needs be apply'd to him improperly and by an accommodation of the name . . whence , again , 't is clear , that all the names , which are spoken promiscuously of created things and god , are spoken analogically ; and their primary signification is that in which they are spoken of the creatures : for , 't is evident , that men first impos'd it on created things , and of them they have , in some manner , perfect notions ; and consequently , names attributed according to those notions are , in some sort , proper : but , they are infinitely far from explicating the divinity : whence , it cannot be doubted , but they are more properly pronounc'd of the creatures then of god. . you 'l object , perfections simply-simple are formally in god , and more originally in him then in the creatures : names , therefore , signifying these , are more originally spoken of god then of the creatures . 't is answer'd , that , 't is evident , all names whatever are translated from the creatures to god ; whence , there can be no doubt which signification is the former : but besides , 't is false that there are perfections simply-simple ( as divines term them ) in created things , which can be signifi'd by humane names ; but those things which are simply , that is , for-themselves-purely , desirable by us , we call simply-simple perfections , and , through ignorance , think they are simply desirable by every thing . . but , ther 's none of these formally in god , as 't is prov'd ; and , if any were , formally , then the same name would signifie god and a creature , in the same signification , and would be univocall . nor imports it , that these perfections descend from god : for so do all others , which yet they know are metaphorically transferr'd . . this notwithstanding , the names which are spoken of god are truly spoken , and it may be argu'd from one to another in him : for , since he that speaks knows he understands not what that is which he signifies by this name ; but knows 't is such as has effects , like those proceed from that perfection , which is call'd by this name in creatures : 't is clear , that this name truly , both signifies what is in god , because the speaker means to signify this ; and , in some sort , makes known god to us , since it manifests god to be something , whence such like effects proceed , as from a just , a mercifull &c. man. . and , since such effects contain others in them , or produce them out of themselves , or they accompany them : 't is clear again , from the affirmation of the said names , we may proceed to the affirming others ; which may signifie , that the consequent effects , too , have their root in god , or , something conformable to their root in men. . you 'l object , at least , there are three kinds of names , which are pronounc'd properly of god : proper names , which agree not to any other , as , to be god , omnipotent , omniscient , and the like , which suit not with any creature , & consequently , are , of necessity , attributed properly to god : next , relatives , as , to be a creatour , lord , iudge , &c. which , being they speak onely an extrinsecall denomination from their effect , it cannot be doubted but they are properly pronounc'd , since , doubtlesse , their effects are from him : lastly , negative names , which , since they only deny something of god , cannot be counted improper ; such are , to be incorporeall , immateriall , infinite , immense , &c. . 't is answer'd , even these names , too , are improperly spoken of god. for , first , those which seem to be properly spoken of god include something common to be the basis of what is superadded , which makes a proper name ; since , therefore , that common is improperly spoken , that proper , too , which includes that common , is improperly spoken : as , when god is call'd omniscient , the searcher of hearts , &c. if science be improperly spoken , then omniscient , if a searcher , powerfull , &c. then omnipotent and searcher of hearts are spoken improperly ; and the same is of the notion , god , whether we take it for a comprehension of all , or whatever else . . again , 't is false that relative names speak nothing intrinsecall , but only an extrinsecall denomination : for , they signify a proportion and a community of the nature of things , which have either an unity or coordination in acting & suffering , or a naturall subjection ; which , if they are not in the things , ( as , in god , in respect of his creatures , they cannot be ) , at least , they are in the soul , since they are express'd in words ; and consequently , even such names , too , are improperly pronounc'd . . lastly , negative names , when they are simple , signifie some positive disposition ; as , to be blind or lame expresse a vitious and defective disposition of the legs or eyes : and so likewise , to be incorporeall , immateriall , infinite &c. in god , explicate a difference of substance distinct from corporeity and limitednesse , that is , a difference under the same genus ; whence , they are improperly spoken of god. . but , if a purely-negative proposition were pronounc'd of god , it would not be improper : whence , that science which inquires into the impropriety of the names which are spoken of god , and denies all things of him , is the most sublime and proper of all . lesson x. of the degrees of impropriety in the divine names . . out of what has been said , 't is easily determin'd which names are , more or lesse improperly , pronounc'd of god. for , there being three degrees of them , the first , of those which signifie things the most excellent in and simply desirable by men ; such as are those we call the vertues , both morall and intellectuall : the second degree , of those goods of the same persons , but participated in others which include imperfection ; such as are the goods of animals or the other things below man : lastly , the third , of those which signifie directly and formally imperfection : . 't is clear , these last are most shamefully attributed to god , and only by ignorance : but , the middle ones , by translation , that a name should be , as it were , first by a common metaphor , used tosignify some vertue and , then again that borrow'd signification , should be transferr'd to god ; for example , when we call a man a lamb for being meek , a lion for couragious , we pretend , too , to call god a lamb and a lion , by the same right as we , before , call'd him meek or couragious . . you 'l ask , since both the names of couragious and a lion are improperly spoken of god , why this should be esteem'd spoken symbolically and metaphorically , and that properly ? 't is answer'd , that , in the creatures we see both the terms , and , therefore , we easily discern when a name is spoken metaphorically and not properly ; for we see a lion to be another thing then courage : but , when names are transferr'd to god , one of the extremes is obscure to us , and consequently , the translation , too . . moreover , in a lamb , a lion , &c. besides meeknesse and courage , there are many other things , which 't is not the intention of the speaker to transferre : but , in meeknesse and fortitude , ther 's nothing but their own particular notions ; wherefore , it seems that , of necessity , either they must be in god to whom they are apply'd , or else the name cannot be at all pronounc'd of him : and , therefore , many think these are formally in the divinity ; though they mistake . . out of what has been said , 't is deduc'd , that some things cannot be attributed to god , which yet are commonly spoken of him. first , a distinction , whether formall or vertuall , between his predicates : for , they that affirm these things observe not that distinction is a name of negation and imperfection ; whence , for these to be in him , either vertually or eminently , is as much as that he can be nothing or defect . . worse , yet , is the notion of cause and effect , in respect of himself , attributed to god ; for example , that his attributes flow vertually from his essence , that he understands other things because he understands himself , that he wills the means because he wills the end , and the like : for , 't is clear , that the notion of an effect , likewise , speaks imperfection ; whence , 't is no eminency to precontain it . . like this 't is , to put instants either of nature or intellectuall , in one of which some thing should be and another thing not-be in god , till the next instant : for , by this , there is put a posteriority in god , which is imperfection . . but , foulest of all , god is put to suppose creatures , or to depend on them , whether possible or actuall ; as , when 't is said , the intuitive vision of god supposes the futurition of creatures ; that god knows not a free act but in its existence ; that a conditionate futurition is presuppos'd , before the disposition of the divine providence ; and such like : which , since they make the divine essence , really , both posteriour to and depending upon creatures , are intolerable and absurd . . the imperfections , too , either of the things god has made or of our understanding , they unwarily cast upon god : as , when god wills the means should be for the end , they weakly suspect that he wills the means because he wills the end ; when any one act of god is conceiv'd by us , we not conceiving another , they believe that there is something in god , too , whence one notion may be , though another be suppos'd not-to-be . . it appears , out of what has hitherto been said , that , of all the names attributed to god , the name of being sounds least imperfection : for , both it stands in the highest degree of actuality , whereas the rest speak act only ; and 't is most universall , whence it has this , both to contain all things and not to be bound to differences , and therefore , to include the plenitude of perfection : and lastly , being or existence is perfecter then essence , which is nothing but a capacity to that ; but , all other things are in the order of essences and more imperfect . lesson xi . of the existence , nature , and science of intelligences . . out of the premisses , 't is easily collected , that there is some substance , by its nature and originally , incorporeall : for , since god alone is being of himself , and whatever is produc'd participates existence from him , and existence , among those things which integrate a thing , is the least unlike god , and is the most perfect and supreme ; it appears , that all other things which are in a thing are caus'd by god , by the means of existence , and that alone immediately flows from god ; and , by consequence , nothing is immediately made by god , which is not in the creature in vertue of existence . . again , 't is clear , that , supposing whatever bodies to exist , they , because they are many , must be in a determinate place : and because , the same things being put and none chang'd , there alwaies remains the same ; all bodies , in vertue of existence alone , if nothing be chang'd in them , will alwaies remain in the same place ; and consequently , in vertue of god alone and bodies , there will not any motion follow . . since , therefore , it appears in bodies , that there is motion ; 't is evident , there is some incorporeall creature : which , because 't is requir'd to give the first motion to bodies , cannot be a separated soul , whose birth presupposes the motion of bodies . . 't is plain , again , that , since this creature receiv's its being from god , of it self it may not-be ; & consequently , includes in it self a divisibility of existence from its essence . . again , out of what has been said concerning a body , 't is evident , that 't is not compounded of matter and form ; and a composition of existence with any thing above it is impossible , since existence is the most formall form of a thing , and consequently , there can be nothing more formall or superiour to it in the thing whose ' t is . . counting , therefore , those things which integrate a thing or being , there are three kinds of things : god , filling the highest degree of existence ; bodies , by their latitude immensly expanding the infinity of matter ; and this middle kind of act , neither essentially actualiz'd , nor flowing into matter , possessing and filling a kind of middle order of subsisting . . 't is , therefore , a pure act , because 't is not mingled with a substantiall power or possibility : 't is not the purest , because 't is compounded with existence , which is a substantiall composition & , as is manifest , common to all but that one thing of-it-self . . again , 't is evident , that an incorporeall creature is intellective ; & , so , actually , understanding : for , since the necessity of its existence is collected from the motion of bodies , 't is evident , it has some power to alter bodies , that their motion may follow ; wherefore , since action proceeds from an agent as it actually is , that motion of bodies must , of necessity , be actually in this creature , & consequently , the bodies chang'd . . since , therefore , ther 's no matter in this creature , nor , consequently , any determination of matter , as its motion or quality ; it comes to passe , that bodies are in it as existing in themselves , that is , as another thing : since , therefore , to be known is , to be , as another thing , in another , this our creature is cognoscitive ; and since , to be known by the notion of being , or as existing , is to be understood ; and movable things are known to exist ; the creature we are in search of is an intelligence . . it follows , too , that an intelligence , in its own essence known , knows god and all other things that exist : for , since an intelligence has whereto an existing thing may be conjoyn'd , retaining the property of its being another ; & , it s own essence existing is intimately conjoyn'd to this power ; 't is clear , that it primarily and formally so inexists . . and , since , knowing that its own essence exists , it must needs see that it exists accidentally ; it sees evidently , that it has a cause of existing , and that such an one as we have been in search of above : it sees , therefore , in its own essence , that god is , and is such as we have been enquiring after , and far perfecter then we can decypher . . it sees , therefore , that nature actually emanes and flows out from him ; and , because it sees what is the end of nature , viz. that so many kinds and subdivisions of animals should shoot-out and ripen into spirits of eternall being ; it sees what is necessary for this ; and consequently , the whole plot of the world , and wherein it self will be usefull for it . lesson xii . of the comparison of intelligences to souls and bodies . . t is clear , too , that an intelligence has a reall divisibility of essence from knowledge : for , since , 't is of the notion of the knowledge of its essence , that it exists , and its existing is divisible from its essence ; much more the knowing its existence , which is posteriour to and supposes its existence ; . since , too , its essen̄ce is limited to a certain degree of existence whereof 't is capable ; 't is clear , the plenitude of being is not essentiall to it : since , therefore , by its knowledge , it has the plenitude of being , knowledge is not essentiall to it : there is , therefore , a non-repugnancy in its essence to the not-having such knowledge ; and consequently , a reall divisibility of its essence against its knowledge . . you 'l say , that power is in vain which is never reduc'd to act ; but , this divisibility is not reduc'd to act ; therefore , 't is in vain , & ther 's none . 't is answer'd , 't is not a power , but a non-repugnancy , which was in act whilst the intelligence existed not . . out of what has been said , we are arriv'd to the comparison of an intelligence to a separated soul : for , as they agree , in that they are both immateriall things , existing by their own existence ; so , they disagree , in that an intelligence is adequate to its existence , but a separated soul exists by an existence which is , by nature , common to the body , and consequently , 't is not adequate to its existence . . again , though both understand their own essence and , by that , other things ; yet 't is with this difference , that an intelligence has this knowledge of it self from its manner of existing , but , a separated soul , from its body : for , when , as 't is above said , something strikes a man , it makes him know that is , because it strikes him ; but , his being struck includes that he is ; therefore , in all knowledge , a man must needs know that himself is : the soul , therefore , has , in its first knowledge , the notice of its own existence and , from the body , receiv's the knowledge of its being ; which unlesse it carry'd along with it , it could not reflect upon it self whilst 't is separated , because 't is a power or possibility ; for a power is indifferent to an act and non-act , and has neither but by force of an agent distinct from it . . this , therefore , is the universall difference of separated souls from intelligences , and proper to them as they are incompleat spirits : that a soul , out of the pure notion of its identity with its intellect , does not inform its understanding ; for , otherwise , it would not be a power : but an intelligence has this , out of the very genericall manner of its nature , by the force of identity to be present to its intellective vertue . . hence , again , it follows , that a soul , in vertue of those things which are in it by the communion of the body , is carry'd to all other things : but , an intelligence , in vertue of its own essence existing . . a soul , therefore , even in separation , uses these common notions it findes , impress'd in it ; and consequently , too , by other such like , attains to the plenitude of being : but an intelligence , by the pure degrees of things , at sight of one thing , transcends to another , nor needs incomplete notions . . lastly , a soul , because 't is naturally the compart of a certain body , is determin'd to that , nor can act upon another but by means of the motion and affection of its own body : and , it affects its proper body by identification ; because the impression or alteration of one is , of necessity , the alteration of the other , according to its manner , by reason of their identity . . but , an intelligence is not determin'd to any body , but indifferent , and is determin'd only by choice to this rather then that ; and changes that , because , being of it self in act and exercise , the exercise , according as the corporeall nature is subject to it , passes into the body , by reason the intelligence is in such a determination . . again , since an intelligence and a body are call'd , univocally , things , and the notion of existence is found the same in both ; and all existence which is a compart with essence is , of necessity , proportion'd to a part of being , and limited : but , between two limited things under the same univocall notion , there must needs be a proportion : 't is evident , that bodies are not infinitely inferiour to intelligences , in the notion of substance ; and consequently , that the action , too , of an intelligence upon a body is not but in proportion . . and indeed , if the operation of an intelligence , viz. motion , were suppos'd unlimited in respect of a body : it would not be connaturall for an intelligence to move a body , but to change it instantly , nor for a body to be mov'd by it : that nature , therefore , might grow up by continu'd degrees , there would need a kind of thing of a middle nature , between bodies and separated souls , on one side , as the summe and fruit of bodies ; and an intelligence on the other ; to which middle creature it should be connaturall to move bodies . . be it , therefore , certain that an intelligence's power of moving is limited ; but yet , rais'd , too , above the motive power of a soul : and immediately 't is deduc'd , that , because there are many primarily-mov'd bodies and , as it were , suns ; nor is it likely that one intelligence can move them all ; many intelligences , too , viz. a severall , to the severall suns , must be assign'd . lesson xiii . of the distinction , subordination , and number of intelligences . and , because to be another thing , as another , is the notion of knowledge , and , out of that , follows the comparative power , or , that many may inexist together ; it appears , that the perfection of understanding is argu'd from hence , that more may be together in one understander then in another : but , since , in intelligences , as also in a separated soul , all things inexist together ; this togethernesse must not be referr'd to the time but to the way of knowledge , that they should be accounted together which are contain'd under one step or divisibility . . intelligences , therefore , will be essentially distinguisht , in that one comprehends the universe , by fewer links and knots , as it were , then another : so that , the supreme , by one divisibility , knows whatever is and what , according to the order of nature , can follow out of these ; and this capacity follows out of the amplitude and eminency of its substance : the lowest is that which has , for the severall substances , severall divisibilities . . 't is manifest , out of what has been said , that there is a perfect subordination amongst the intelligences : for , the superiours comprehend the adequate perfection of the inferiours , and not in part only , as 't is in bodies . . moreover , a superiour is active upon a greater body , or more active upon an equall body , then an inferiour : whence , if each be suppos'd willing to act diversly upon the same body , the superiour will prevail , and the inferiour will not be able to act . . it appears , notwithstanding , that this subordination extends not , to this , that a superiour intelligence can act upon an inferiour , or contrariwise : for , since there is not in an intelligence any notion of power or possibility , consequently , neither is there any mutability ; but , as its existence once infus'd , by reason of the connection with its form which has not an indifference to more , remains unchangeable as long as its form ; so also , the knowledges of an intelligence cannot , like accidents , be present and absent , but , once infus'd by the power of the giver , they are subject to no mutation but from him. since , therefore , there is no other divisibility of an intelligence , but either in its being or its knowing ; 't is evident , it can receive no change from another intelligence . . 't is apparent , too , that , because an intelligence embraces whole nature , by necessary deduction ; it has , of necessity , in its very birth , all the good which 't is ordain'd to have : since , the good of every thing is that which is according to its nature , and , the whole possible good which can belong to a creature , whose entire nature is to be intellectuall , is to understand : whence , since an intelligence understands all things by force of its nativity ; by the same gift that gives it being , it arrives to the possession of all connaturall good . . every intelligence , therefore , is blessed , in respect of the good it possesses ; nor can it lose this beatitude , more then its essence with which 't is conjoyn'd . . lastly , 't is evident , there are three things chiefly to be consider'd in intelligences , understanding , will , and action : among which , action is the meanest , as being about inferiour things ; & though , by it , they rule over bodies as instruments , yet those things must needs be nobler by which themselves are perfected , which things belong to the vnderstanding . . and , the will differs no otherwise from the understanding , then the imperfect understanding from the perfect : for , when the things that are understood are appropriated to the nature of the understander , and are made something of it , then the understanding begins to be will. 't is evident , therefore , that the will is of those intelligible things , the understanding whereof most of all perfects the understander . . wherefore , the greatest nobility of intelligences is , to excell according to will ; the middle , according to understanding ; the lowest , according to action : though , 't is clear , that these notions are so correspondent to one another in intelligences , that , as much as the will of one excells that of another , so much , too , must both its understanding and power of acting . . now , that the multitude of intelligences is but finite , 't is evident from hence , because all multitude ( since it rises and is encreas'd from one by unities , and unity cannot be a step from a finite to an infinity ) of necessity , is finite . . but , since they are not made for the good of another thing , as their end ; nor have any thing common , whereby they should naturally respect one another ; nor any order of cause and effect ; and there is no term , no limits of understanding : limitation , among them , cannot depend on any other , then the occult proportion of their natures , by which they integrate the compleat order of being without matter . lesson xiv . of the action of god , intelligences , and bodies , severally . . from the knowledge of the agents , by the same steps we are led to the knowledge of their actions . first , therefore , 't is evident , out of what has been said , that , since god alone exists of himself and essentially , something flows immediately from him ; and consequently ▪ is created , and that god creates : for , 't is evident , what is made is made out of no presuppos'd matter ; since god himself is mutable , and no thing , besides , preexists . . 't is plain , too , this action is in an instant : for , were it in time , since , in the intermediate time , there is no substance wherein it should be subjected , it would neither subsist nor be in another : wherefore , of necessity , some substance flows instantaneously from god. . 't is manifest , therefore , that both the intelligences and the first bodies proceed from god , by such action . . nor must it be ask'd , by what extrinsecall power they receive birth from god : for , since god is essentially being it self , 't is plain , that whatever is requir'd , intrinsecally , for god to be a cause actually causing , is essentially found in god ; and , since nothing besides himself exists , that which is in him is of such vertue that the effect follows ; wherefore , 't is a necessary consequence , because the subsistent being is being it self , creatures are , or , if being be , the creature is ; as if you should say , if the sun be not capable of its own light , the things about it are illuminated , or , if the fountain overflows , the neighbourhood is watred . . again , since an intelligence can neither act upon god , because he is immutable , nor upon another intelligence , nor upon a separated soul , which , as to that , is of the same nature with an intelligence ; its action is wholly about bodies : and , action about a body , if it be compounded of more , is known by the simples whereof 't is compounded ; now , that there are only three simple actions has been evidenc'd , ( by shewing how all actions are perform'd ) in our physicks , viz. locall motion , condensation , and rarefaction . . and , for locall motion , 't is manifest that 't is , really , nothing but the division of a magnitude : and the division of a magnitude consists both of the conjunction of the dividing body to the divided , and its separation from the body with which 't was formerly one : to conjunction there 's nothing else requir'd , but that no quantity keep off the place from what is plac'd in it , since magnitudes between which no other interposes , even by that , are one together ; now , that there should not be another between them is a certain negative notion and , by consequence , is not made by an agent on set purpose , but follows out of the action of a body intending another thing , viz. from a body impelling . . but , the body impelling either it self changes place , without any other mutation , and then , it self , too , is impell'd ; or else , from some other mutation only it receiv's the being impell'd , or , without impulse , to impell : since , therefore , besides division , there are but two simple mutations , rarefaction and condensation , and condensation is both a negative action , as being the less'ning of quantity , nor makes it the body aspire to anothers place ; 't is plain , there 's no simple , properly call'd , action in bodies , but rarefaction . . since , therefore , 't is clear , that the action of an intelligence is a simple and properly an action , as , that which begins and causes the action of all other bodies ; it comes to passe , that the proper action of an intelligence upon bodies is rarefaction : and , since ther 's no other action , properly , upon a body , nor has an intelligence any action upon any other thing but a body ; it follows , that rarefaction alone is the action of an intelligence . . you 'l ask , wherein consists this action of an intelligence upon a body ? or , what consequence is this , an angel wills , therefore a body is rarefy'd ? 't is answer'd , out of what has been said , 't is clear , that an intelligence , by love or desire , ingrafts the thing to be done into its own essence and existence , in a particular manner , as if it were something of it self : whence , 't is plain , that the intelligence , by the act of its own being stands bent to the body upon which 't is to act , according to all the circumstances necessary , out of its own knowledge to the effect . . on the other side , 't is plain , both that the body is susceptible of the desired effect , and that the effect follows out of , or rather , is but the eminency and excesse of its own act , or form , that is , quantity , upon matter , nay , of its commonest act or corporeity ; as also , that the body is , in some sort , continu'd to the intelligence , by its form or substantiall act . . and , though the act of the intelligence is of another kind , yet , because the notion of existence , to which both dispose , is the same ; the act of the body must needs , from the assistance of the intelligence , grow , as it were , and be chear'd ; and consequently , more overmaster its possibility ; and , which follows , the substance be made rarer , either to the transmutation of the substantiall form , or within the same nature . . we answer , again , 't is evident , that , precisely out of the notion of understanding , ther 's a connection between the understander and that which is understood : in such an one as receiv's his science from the objects , the object is the cause of understanding ; in one whose understanding is his being , the being of the thing understood is from the understanding ; lastly , in one whose understanding is neither his being , nor from the object , but concreated and naturall to him , the changes in that which is understood ( if it admit of any without the change of existence ) may be from him . . next , from hence is understood the operation of a body , wherein that consists , viz. in nothing else but in the formall power of existing what it is . for , let there be three bodies , a , b , c. following one another between the parallell sides of three places , or of one place equall to all the three ; and let an intelligence rarify a : since that cannot encrease , unlesse either b be diminish't or driven on , so long as 't is easier for b to be condens'd then to drive on c , so long b will be condens'd ; when 't is arriv'd to the term of condensation , by little and little it encroaches into the place of c , and forces c to enter into the place of another ; till 't is come into so ample or condensable a field , that the rarefaction of a operates nothing else but condensing the farthest body , and then the motion ceases . . the operation , therefore , of a is , to be greater , whence follows a 's being united , according to some part of it , to the place of b : again , the operation of b is , either to be made lesse and so only to quit its place , or else , keeping it self in its quantity , to unite it self with the place of c : since , therefore , to be united to the place of c is nothing else , but to be a magnitude between which and the place of c ther 's nothing interpos'd ; the whole operation of b and a is no other , then to be what they are , by a kind of formall consistence . . because , therefore , a body has no operation but division , 't is plain , that the whole action of a body is reduc'd to being what it is , or a formall consistency in its proportion of quantity to matter and its continuity to place ; and , that its true power of acting is infus'd by intelligences . . 't is plain , too , that an intelligence , by that one rarefactive vertue , can operate whatever is to be done by bodies : for , since all corporeall action is perfected by division , and division is arriv'd to by this vertue , all action of a body is attain'd to by this vertue . lesson xv. of the cooperation of the agents , to the making of substances , a rationall soul , and to all other effects . . hence , we are arriv'd to the production of substances : for , since some are produc'd out of nothing , some out of others preexisting ; the former must , of necessity , have flow'd immediately from god : the agent , therefore , which produces out of nothing , makes all the other qualities and conditions of the thing , by the notion of existence : existence , therefore , is first in execution ; and , since the greater is not made for the lesse , it must be first , too , in intention . . wherefore , since every agent , by acting , endeavours to expresse its own essence upon the effect ; the essence of him that produces out of nothing must be existence it self . . nor is it to be expected , that another creature should be made use of , as to preparing the matter ; both because existence is nobler then all the rest in a thing , whence it admits not of any preparation for the rest , since preparations are only in the baser in order to a better : as also , because , existence being put , the thing is already put : whence , the operation upon nothing is compleat by the very putting of existence , and consequently , of that cause alone which puts existence . . supposing , then , that god has created certain substances ; and that , because , of themselves , they are defectible , they alwaies have that being from god ; 't is infer'd , that god perpetually poures out the power of being , as the sun light. imagine , now , an accidentall transmutation on body's part , ( such as is explicated in our physicall discourse ) , and , ( as 't is declared above ) through certain changes , an arrivall to a constancy of being in another degree . . it must needs be , that , as , when the earth is turn'd to the sun or wood laid on the fire , from the perpetuall and minutable action of the sun or fire , joyn'd with the mutability of the earth and wood , sometimes one sometimes another part of the earth will be enlightned , and sometimes one sometimes another part of the wood will burn : so , supposing that naturall motions make matter , in severall sites , sometimes capable of a perfecter existence , sometimes of a more imperfect ; from the same constant effusion of existence on gods side , the substance must needs be sometimes nobler , sometimes more ignoble , respectively . . suppose , farther , an existent body so chang'd , that the matter may be capable of a form which , in its essence , includes some notion , that exceeds the power of matter : is it not plain , that , out of the very same constant effusion of existence from god , a substance will exist which will be , so , corporeall , that 't will be , in some respect , spirituall ? . for , since the putting of existence puts a thing ; purely at the second causes determinating god to the position of such an existence , not that alone is put , but whatever follows out of it , though it exceed the power of second causes : and so , it appears , how , putting the generation of a man , a rationall soul is put ; and how the power of nature so concurres to it , that yet the notion of creation , or rather of con-creation , supervenes , and is necessary . . lastly , how it both is and is-not ex traduce , and , at once , by generation and creation ; and how , in this case , an instrument , in some sort , is made use of for creation . . and , because the internall dispositions of a soul , as , to know and to will , even they are indivisible , and follow out of the materiall impressions made upon the body : it must needs be that , as the soul it self follows out of the generation of man , by the help of the universall action of god ; so these dispositions , too , from the impression made upon the man , and from the nature of the soul , must indivisibly alter the soul. . and , whoever would see an evident example of these things , let him conceive how , by cutting , a piece of wood is made more ; for , all the time of the cutting , the figure is chang'd , yet the wood remains , by the same unity , one ; but , indivisibly , the cutting being finisht , they are , now , two pieces of wood ; without the dualities beginning at all , before , or any thing of its nature , but only some variation about the figure . . out of what has been said , we are deduc'd to see , how god performs all the works of the creatures in them . for , first , if we speak of intelligences , since their internall operations are nothing else , but to be all other things after a certain manner ; 't is manifest , they are , actually , even to the uttermost positive circumstances , by force of their creation . . for , by force of that , their essence is conjoyn'd to it self , as 't is a cognoscitive vertue ; and , out of this conjunction , the next divisibility , which is , of god to the same cognoscitive vertue , since all the causes are put , is , of necessity , in them . . and , what is said of this divisibility is , with the same facilnesse , discover'd of all the rest whatever ; since they are all connected : their externall action , too , matter , which is its subject , being put , follows , by force of their internall , without any other change in them . lesson xvi . of the government of god , and the locality of incorporeall things . . as for the rest , the same way leads to the discovery that god is not the cause of any imperfection and not-being , or ill , which is in created things and their action : for , since the action of god is only to infuse being , and this as much as the creature is capable ; 't is plain , what there is of being is to be attributed to god , but what ther 's wanting of being is to be refunded into the incapacity of the subject . . and , since the defect of action proceeds out of the defect of the principle , that is , out of some not-being in the principle ; in the same manner , all defect in acting is to be reduc'd , likewise , into some defect in being of the creature , and not into god , as its cause . wherefore , god is the authour of all good , because all good is from being ; but , of no ill , since ill is from not-being . . consequently , 't is evident , that god cannot annihilate any thing , or withdraw his concourse from the action of any creature : for , to be able to annihilate is to be able to make a no-thing ; and , to withdraw his concourse is not to give being to things created ; either of which cannot happen , but from a defect of goodnesse and of the overflowing , as it were , of being in god. . you 'l say , therefore , god does not act freely ad extra , that is , upon the creatures : but , this consequence is to be deny'd ; as 't is said above , when we treated of the liberty of god. . you 'l say again , in the same manner , therefore , it must be said , that god cannot make any thing which he will not make . but , this consequence , also , is deny'd ; for , his power is refer'd to possible things , or , which have entity and intelligibility ; and therefore 't is not to be deny'd that he can doe any thing that 's possible ; though , in another respect , it be impossible it should happen that he should , actually , make this . . but , the power of god , which is the very notion of being and thing , has not , for its act , the not-being of any thing and not-acting ; and therefore , 't is not to be said , that he can give not-being , or can not-act . . let us remember , now , that god understands all and every thing done by the creatures , and wills all things which follow out of his operation ; and , we have it , that god is governour of the world , and that there can be no resistance against his will. . for , since whatever is has its birth from his will , nor can there be any thing which is not effected by him and his works ; 't is clear , whatever he wills not is not , nor can be so long as he wills not that it be . . nor is it lesse evident , that neither the contingency of naturall causes , nor the liberty of rationall creatures is infring'd , by this government of god. for , since contingency is nothing else , but that the nature of the cause is such that it may and uses to be hindered , by other causes ; and liberty , that a creature , upon the consideration of more proceeds to action : and , 't is so manifest , that both these are in nature , and no waies touched by the operation of god ( as that operation is explicated ) that it needs only the remembring : 't is clear , that the government of god is sweet , and offers no violence to the natures of naturall causes . . you 'l object , that propositions , concerning a future , whether contingent or free , subject , are determinately true ; especially , since they are known by god and are predefin'd : wherefore , the effect cannot not-be : there is , therefore , no either contingency or liberty ; whether this happens out of the force of contradiction , or of the irrefragable will of god. . 't is answer'd , 't is false that propositions concerning a future contingent have a determinate truth : for , since a man speaks out of consideration of causes , the sense of his proposition is what the causes may bear : nor imports it , whether it be pronounc'd actively or passively ; as if you should say , what the causes will act , or what effect will be made by them ; for , it signifies still the same . . if it be , therefore , ask'd , what men mean by such propositions , 't will rain , 't will be hot , socrates will be angry or go to sea , & c ? 't is clear , they mean to explicate effects , as in defectible causes , and consequently , they have no determinate truth . but , if it be ask'd , what the proposition will signify , if it be referr'd immediately to the effect , as it sounds ? 't is answer'd , no sensible man uses to speak so or make such propositions ; and so it belongs not to the present question . but , if there be suppos'd such a power of contradiction in the objects , as to determine the truth of propositions ; all things must fall out by the necessity of fate and be from themselves , which is , above , sufficiently demonstrated impossible . . 't is plain , lastly , that this action of god , by which he moves a creature , is miscall'd a concourse ; since such a word leads the hearer into an apprehension of a certain equality in acting , between god and a creature : 't is , therefore , more properly call'd premotion or predetermination ; since god makes us doe even to every the least positive circumstance of action . . 't is collected , too , out of what has been said , how god is said to act in all things , both by the immediation of his suppositum or substance and of his vertue ; but , an intelligence upon one body only by the immediation of its substance , upon the rest by the immediation only of its vertue . . for , since the action of god is the influx of being it self , and nothing can act without being , nor being flow from any but god ; god must needs immediately act upon all substances by creating and conserving them : and consequently , in such his acting , no third substance intervenes between him and the creature . again , the action of all bodies proceeding from intelligences , and they being made act by god ; the vertue of god makes every thing act , and so is more immediate to the effect then the vertue of the nearest cause : whence also , god is , by the immediation of his vertue , more immediate , then the next cause which produces the action . . but , an intelligence , which immediately rarifies a , moves not b , but by the mediation of a ; the suppositum a , therefore , is between the intelligence and b ; wherefore , the intelligence acts not , by the immediation of its suppositum , upon b : but , because a's being rarify'd is the cause that a moves b ; and a is rarify'd by the vertue of the intelligence ; the vertue of the intelligence makes b be mov'd by a ; the vertue , therefore , of the intelligence , not the suppositum , is immediate to b. . and , hence it follows , that god is said to be immense ; but , an intelligence to be definitively in place : for , since nothing either is or can be without existence , 't is clear , neither can there be any place , upon which god does not , immediately , act : but , an intelligence , having a determinate proportion to a body , so acts upon a certain quantity , that it cannot , together and at once , immediately act upon another . since , therefore , incorporeall things are not in place circumscriptively ; an intelligence must be definitively , but god , without end , in all place , by immediate operation . lesson xvii . of the conservation of creatures , and the durations of things . . t is clear , too , out of what has been said , that this action of god is the conservation of things , both as to their substance , and as to their intrinsecall accidents : for , since the essence of created things has not , of it self , a necessary conjunction with being , but such an one as may , of its own nature , be lost ; 't is plain , they are not conjoyn'd , by force of their own notions , for that time during which they may be not-conjoyn'd ; and , by consequence , as long as they are conjoyn'd , they have this , to be conjoyn'd , from an extrinsecall ; they , therefore , remain conjoyn'd by an extrinsecall power . . but , 't is of the same nature , to be conjoyn'd and to remain conjoyn'd , or , to be for any duration conjoyn'd ; they have , therefore , this from the same cause and vertue : and , since 't is not any change , but , on the contrary , the effect is that nothing should be chang'd ; by the very same action , too , they keep their being , which is , to be conserv'd . the same action of god , therefore , is conservation , in respect of substances : and , since 't is declar'd above , that intrinsecall accidents are nothing else but manners of substance ; the substance being conserv'd , 't is clear , that they also are conserv'd in their being . . out of what has been said , too , we may know , what action signifies in the effect it self : and , if the question be of the divine action , as it immediately flows from god , 't is plain , that 't is the very substance it self ; not only , because it cannot be subjected in a substance , which subsists no otherwise then by it ; nor , because the existence of things form'd out of our conceits is universally rejected ; but also , because any intermediate action ( such as the moderns feign the making ) which should be put , serves to no purpose . . for , either god , before this action , is determin'd in himself to act , that is , that this action should follow from him , or , he is not ; if not , this action will not follow , for , from an indifferent nothing follows ; but , if he be determin'd , this action has not the power of determining him , for which the opponent requires it as necessary : but , the effect can , as immediately , follow out of himself , as this action . and , this same discourse holds against the like fictitious action , too , of creatures . . again , in as much as the action of god is conservation , 't is nothing but the very being of the thing conserv'd . for , first , the duration of an incorporeall thing cannot be divisible ; for , if it were divisible , 't would be continuate and divisible without end : either , therefore , some part , together and at once , in an incorporeall , that is , indivisible thing , or not : if together , that part will not include succession ; if not , no part can ever be . . and , this argument has not lesse force in a corporeall creature ; for , though it be divisible in extension , yet , 't is indivisible in succession , and consequently , it cannot sustain together more parts of successive duration . . again , if , to endure be , for the same thing to be the same it was ; is it not clear , ther 's nothing requir'd but a non-mutation ? and , on the other side , that , of two things which exist , if one perish , that 's said to be chang'd ; that which endures remaining still unchang'd ? there is , therefore , no novelty in permanency . . moreover , to change the existence , the essence , too , must needs be chang'd , since , 't is the aptest capacity of existence : the notion , therefore , of substance will be in perpetuall change and instable , and consequently , out of god , nothing stable . . you 'l object , since 't is often said , that a creature may not-be , and yet , whilst it is , it cannot not-be ; 't is manifest , that its cannot not-be , or , to be whilest it is , successively supervenes to a creature : since , therefore , ther 's a greater necessity of indivisibility , on god's part , then on a creature 's ; the succession is to be concluded on the creatures side . . 't is answer'd , 't is just contrary : for , as , if the action of god were put ( by way of imagination ) to be successive , no man would require any other succession , to understand the duration of a creature ; so , if the action of god be put equivalent to continually successive , no man can complain of the unintelligibility of duration . . because , therefore , the action of god is conformable to his existence , and his existence indivisibly comprehends the past and future ; it must needs be that the action , as it is the internall determination of god , in the same manner comprehends succession . this action , therefore , actuates the creature , with a certain indivisibility that eminentially contains divisibility ; and , without any divisibility , makes the existence of a creature , by contradiction , impossible to be taken away successively ; yet , without any more then a vertuall succession intervening in the creature . . for , what has formally the vertue which is in succession , can as well perform this as succession it self : but , such , we have said , is the action of god : whence , 't is plain , that , even from this effect , the notion of gods eternity is demonstrated à posteriori . . hence , 't is deduc'd , that the duration of corporeall and spirituall substances is , intrinsecally different : since , corporeall substances have , from the notion of matter , an intrinsecall possibility to not-be ; and consequently , a weaker connection to being , intrinsecally , out of their own nature ; but duration consists in the connection of existence and essence , as to the effect of permanence . . adde to this , that there are , in nature , causes which destroy bodies , but , there are none which are able to infest spirituall substances : whence , since god destroyes nothing , of himself , intelligences are absolutely immortall , as also , separated souls ; and bodies , when motion ceases , will be immortall accidentally , in the mean time they are simply mortall , unlesse perhaps there are some exempt from the generall order . . out of what has been said , too , both the notion and difference of three durations is evident : of time explicated at the beginning : of eternity , when we treated of god : lastly , of eviternity in intelligences . lesson xviii . of the manner of action , on the subject's side . . the solution , also , of that old question is evident , why god made not the world before ? for , if we consider , that ther 's no beginning of an infinite , and that , where ther 's no beginning , there can be no determinate distance from the beginning ; it will appear , that 't is impossible there should be any eternall flux of time or instants , ( even by imagination ) , wherein there can be taken a now and then , and any constant difference of duration , or , something to be before , something after , determin'd . . wherefore , such a question proceeds from the weaknesse and infirmity of our understanding , and signifies nothing ; and consequently , bears no answer : for , for god to make this world before , in time , that he made it , would be to have made a world before a world ; since , the time of the beginning of the world is nothing else but the very motion , with which the world began to be mov'd . . in like manner , evident is the solution of that question , whether god could make a permanent thing ( that is , whose essence includes not succession ) from all eternity ? for , if there be no quiddity or possibility of an infinite in succession ; 't is clear , that god could not so make a creature , that it should have eternity , by relation to infinite succession : therefore , not otherwise then by some positive eminence confer'd on it : since , therefore , duration consists in the connection of existence to a thing , he could no otherwise make a creature from eternity , then by giving it such a connection by which , simply , it could not not-be , wherein consists the very eternity it self of god. clearly , therefore , 't is impossible that even a permanent thing could have been from eternity . . but , as for the not-immediate action of god , or ( which is all one ) as 't is the same with the action of the creature , 't is plain , the same account is to be given as of the action of the creature . and , of these , philosophers have pronounc'd , that action is something between the agent and effect : as , in the change of place , between the rest in the term whence and the term whether , there interven's motion ; which they falsely imagine to be more beings-in-place successively , since , as aristotle has demonstrated , all that time the movable happens not to be in a place equall to it , whereas , yet , equality is of the very notion of place . . so , too , in other mutations , especially that which is call'd substantiall generation , the subject , by the precedent motion , which properly is the very action , is not , neither actually nor in part , in the term it self ; but is chang'd only in its quality . . so , too , it falls out in rarefaction , which is immediately from an intelligence : for , since the proportion of an intelligence to a body is finite ; it cannot , instantaneously , reduce a body to any how-little-soever-a degree of rarity : wherefore , there must of necessity , between it prepar'd for action and the term , intervene some motion ; during which , the body rarify'd is neither in any determinate degree of rarity , nor in any determinate place . . out of all which , this , at length , is concluded , what a kind of being passion or mutation has in the subject : for , since 't is repugnant , the formall parts in a compound should be actuall ; they must be only in possibility or power , and some other third thing , resolvable into parts , actually exist . . this third thing , therefore , has a certain resolvable and changeable nature ; wherefore , 't is clear , there is some cause which has the power of changing it : let b , therefore , be the changeable nature , a the changing cause ; if a be apply'd to b , must not b , of necessity , become another thing then it was , that is , be chang'd ? . this is , therefore , for b to have suffered by means of a , viz. to become another thing then it was : another thing , i say , or altered ; for , if nothing perceivable remain , 't is become another thing ; but , if there remain whereby it may be mark'd to be this same as was before , 't is only altered , because the foundation , or , that which is the sustainer still remaines , but 't is innovated in some respect . . for example , let there be a gallon of water in a cubicall vessell , and ( to avoid dispute about a thing that concerns us not ) let 's suppose the figure to be nothing else , but that that very quantity , according to its three dimensions , be no farther extended then , actually , 't is ; ( which conceit , being purely negative , can adde nothing to the quantity ) : let the same water , then , be suppos'd in a vessell of another figure ; and consequently , it self , too , to have put on other limits : since the former terms were nothing but the very quantity of the water , neither can the later differ from it . . 't is evident , therefore , that this quantity , remaining a gallon , ( which is its difference , whereby , as quan-tity , 't is limited ) , has a possibility to be , now pyramidall , now cubicall ; and consequently , is changeable , no thing being chang'd : to this possibility , therefore , if the power of two such vessells be suppos'd successively apply'd ; 't is clear , purely upon the water 's and their conjunction , there follows a change in the quantity of the water , by little and little , and , at length , what in one vessell was of one figure , in another becomes of another , chang'd according to the manner , unchang'd according to the notion of quantity . . thus , substances become altered , according to qualities , the quantity unchang'd ; according to quantity , the substance unchang'd ; according to substance , the matter remaining : for no other cause , but that the subject or that which suffers is so mutable , and an efficient , which has the power of changing , is apply'd . a theologicall appendix , of the beginning of the world . wherein , 't is essay'd how subservient philosophy is to divinity . same authour . cant. . equitatui meo in curribus pharaonis assimilavi te , amica mea . printed in the year , . to the reader . since philosophy has then attain'd its dignity , when , apply'd to action , it renders man better , that is , more man ; and christians are initiated to this by divinity : this , evidently , is the highest pitch of philosophy , to wait on and be subservient to the traditions deriv'd from god. wherefore , i saw it absolutely necessary , to fortify the institutions , i would recommend to thee , with a subsignation of theology . nor was i long to seek whether i should first addresse my self : for , when , after the notions of nature digested in common , i had expos'd the same in a collection of the world , as it were , in an example ; by the same rule , having exhibited the action of things , like a sceleton , in its principles , in the last book of metaphysick , i saw my self oblig'd to vest it , in the creation , with the nature due to it. and , since in the ancient theology , we had this accurately decyphered , beyond the attempts of philosophers ; but untraceable , because the paths of nature were unknown : it seem'd to me , a more expresse seal of theologicall approbation could not be desir'd , then that the institutions should carrie a torch before the mysteries of genesis ; and , from those so discover'd , receive themselves , with advantage ; the glory and splendor of authority . what more ? i essay'd : thou seest the issue ; which i wish may benefit thee . a theologicall appendix . of the beginning of the world . chap. i. a philosophicall discourse , concerning the creation of heaven and earth . . since we find by universall experience , without any exception , that , not only the operations , but , even the very subsistence of all bodily substances is by continued steps brought from possibility to be in act ; nor can we doubt that the parts and the whole are of the same nature ; 't is evident , the beginning of the universe it self , if we suppose it manag'd according to the nature of bodies , must proceed by the same rule ; that , from the nearest power and possibility in which it could be , it has been rip'ned by degrees to this excellent beauty , and did not by instantaneous creation immediately start into perfection . . because , therefore , god subsists by the very necessity of being it self , and in being it self there can be nothing of imperfection , 't is clear , that his ultimate intrinsecall formality and free act preexists before , not only the existence , but even , the very essence of all and every creature , as much as whatever is most essentiall in him. . as also that this being , which they have receiv'd from god , is the nature of the creatures , nor can they otherwise flow from god then according to their naturall condition . especially , since god acts not to attain an end prefix'd to himself ; but this is his end , ( if we may call any thing an end in respect of god ) that the creatures should be , so , as , in his essence , science and will , he has predesin'd their determinate nature fixed and inviolably to be ; that the whole universe might emane his most beautifull image , and , in a manner , a most adequate participation of himself . . so that , all things that are to have their most connaturall quality , as far as it can stand , impartially , with the perfection of their fellow bodies ; this is that which god will'd , and what , in effect , he has brought to passe . . be this , therefore , firmly establisht , that god not instantaneously , but by a congruous disposition of diverse degrees brought up the world from its deepest possibility , that is , its simplest and fewest principles , to its due perfection . . again , because neither materia prima nor any other part of a thing , but only physicall compound , is apt to receive exiastence : and , of physicall compounds the most simple and , as it were , most poten , tiall , that is , next above mere possibility , are the elements : and something must , of necessity , have flow'd instantaneously from god : it follows , that some one or more of the elements were , by creation , call'd by god out of the common abysse of nothingnesse . . but not one only element was created . for , since motion does not follow out of the sole vertue of creation : nor could motion be without division ; nor division without a substantiall difference of the divider from the divided ; nor this be made , even by angelicall vertue , without time : it follows that more elements were created immediately by god. . yet not all the four : since fire we call an element that makes it self be seen , which implyes action ; but corporeall action is not without motion ; nor motion from pure creation . . but , of the other three elements no one could be conveniently omitted : for earth and water are those we see mixt by fire through the whole course of nature ; and fire is immediately generated and nourished by aire : if any one therefore , of these three had been wanting ; the matter had been unfit for angelicall operation . . three elements , therefore , were created ; nor those confus'd in a chaos : for such a confusion had not exhibited the most simple matter , but a disorder'd multitude of mixt things ; since mixt things emerge from a mere confusion of the elements . . earth , therefore , was the inmost , as the densest and of constant nature : aire was the outmost , as the most opposite to earth : the middle both nature and place water possess'd . chap. ii. an explication of genesis concerning the same . . let 's see , now , whether the christians most ancient theology , deriv'd from the hebrews , speaks consonantly to this . god ( saies it ) in the beginning created the heaven and the earth . the beginning , saies , not so much a precedency to things that follow'd , since it self was something of what was began ; as that nothing was before it . admirably , therefore , by this term , 't is express'd , that the creation of heaven and earth was , so , instantaneous and , in a manner , before the rest ; that neither any time interven'd , nor was it self in time. it shews , therefore , that they were created out of nothing ; and that , instantaneously ; and , that the rest immediately follow'd out of these once put . . nor can it be doubted what it calles heaven and earth , since the name of earth is immediately us'd afterwards : whence , 't is evident , that , by the remaining name of abysse , is express'd what before was call'd heaven ; otherwise , the sacred text is confused and imperfect . . 't is added , that the earth was void and empty ; according to the hebrew expression , solitude and emptinesse , or rather , of solitude and emptinesse ; for , so , the hebrews often expresse their adjectives . the sense is clear , that neither were there men upon the earth , whose properties are fellowship and conversation , the privation whereof makes solitude ; nor plants and animals , which , as bodies and utensils , might fill the place and house of humane habitation . . it follows , that darknesse was upon the face of the abysse . the word abysse , says a gulph of waters whose bottom is unknown , or not reach'd ; and because the most simple manner of reaching is by sight , it properly signifies such a depth of water , that sight cannot reach its bottom . wherefore , the sense is most easie , that , what it had formerly call'd heaven was a vast diaphanous body , upon which there was no fire to enlighten it . it affirms , therefore , directly , that fire was not created . . but it subjoyns two parts of the abysse , whilst it says , and the spirit of the lord was born upon the waters . clearly , therefore , it affirms three elements , earth , water and aire , were created by god ; but not fire . and , that they were not confus'd is evident , in that , otherwise , it had not been an abysse , that is , a capacity of light , and a privation ; since by the commixtion of earth the other elements had been rendered opake : moreover , the spirits being born upon the waters denotes a distinction of places between the other two elements . . but 't is observable that the word , was born , according to the force of the originall term , speci●ies that motion whereby birds sustain themselves with open wings over their nests , least they should crush their young ones ; and yet , to defend them from the cold . whence , a certain person amongst the hebrews explicates it , not weighing upon , touching , but not striking : wherefore , the aire cover'd the water , but press'd it not . 't is plain , therefore , that according to the propriety of the expression , 't is specifi'd , there was as yet no gravitie , and that the aire is the first of the elements whose property it is to have any heat in it . 't is evident , therefore , ther 's no gravitie in the aire , of its own nature ; and consequently , that 't is not an intrinsecall quality in the other elements , but is in them from the operation of fire and the order of agents . chap. iii. a philosophicall discourse of the vvorks of the tvvo first daies . . the matter of the world being created , it remains that we see what follow'd , by the additional operation of creatures . and because the operation of angels is no other then rarefaction : & nature wanted its naturall instrument , viz. fire ; for this we see principally made use of for almost all naturall effects , especially , the generation of substances : and this is not rais'd out of water and earth immediately without first becoming aire : it must be , that the angels or angel whose task this was , by rarefying the aire rais'd a vast fire . . and since there are many sorts of fire ; and that , which , far from the fiery body , smoaks no longer , but shoots out directly with pure rayes , is , by a speciall name , call'd light : light must needs have been made by the angels , through the rarefaction of pure aire , as , from which no smoak rises . . nor is it lesse certain , this must be done in the very confines of aire and water . for , since the angels could not in an instant convert aire into light ; and a locall motion of the neighbouring bodies follows upon rarefaction ; the aire must needs have been mov'd whilst 't was yet in the form of aire : and since motion cannot be without a plurality of substances , 't is plain that the aire divided the water ; and consequently , the first fire was rais'd in the confines of both . . since , therefore , the fire being rais'd , of necessity , acted upon the water ; it follows , that the waters being stir'd , those particles to which the fire stuck , ( being rarer then the rest , and coveting still a larger place ) , by their own and the denser parts of the water's motion , must needs be thrust out into the aire , which is more yielding : and those excluded , be aggregated together , specially towards the light , where , by reason of the more vehement action , there must needs be greatest abundance of them : and , more flowing from one side then another , ( since naturall causes work not rigorously even ) , the whole masse of water , and earth adhering to it , by little and little attain a motion towards the same light ; so that , successively and by parts , it rol'd in a circle and was enlightned , having in some places night in others day . . besides , another effect must evidently have follow'd from this production of light , viz. a vast abundance of clouds be rais'd up into the aire , which , by the circulation of the light about the inferiour globe , must necessarily be remov'd a vast distance from the globe it self and the light : whence , being no longer sensible of the globe's attraction , they could not , by any order of causes , be remitted back towards the globe . thus , therefore , ther 's a vast space establisht , between the waters in the globe , whence the clouds were extracted , and between those very clouds themselves ; which may keep them from one another separate for ever or , at least , till the end of the world. chap. iv. an explication of genesis concerning the same . . what says theology to this ? it says , and god said , let there be light ; and light was made . speech and command are address'd to another : clearly , therefore , it reaches that , by the intermediate operation of angels , light was made . . and it was made , clearly shews that the making immediately and instantly began , viz. that there was no delay in the intermediate instrument ; wherefore , that 't was an incorporeall substance which needed not be mov'd that it might move : moreover , the word he said , which implyes knowledge , declares it to have been an intelligent instrument . . it adds , and god saw the light that it was good . goodnesse is perfection : namely , because the nature of the elements , by the addition of fire , was compleat and perfected ; therefore , light is said to be good : again , because the rest of the elements were passive , and light active ; therefore light is call'd good or perfect : for , what has attain'd an aptitude to produce or make its like , is esteem'd perfect , in its kind . . it follows , and he divided the light from the darknesse &c. 't is plain , this division was made , not by place but by time , since day and night are parts of time : and consequently , that motion or the diurnall conversion was now begun ; which is declar'd by those words , and he call'd the light day and the darknesse night . for , since , as yet , man was not , to whom words might be significant ; he call'd is as much as he establisht the essence of day and night : for , a name or appellation denotes the essence or quiddity of the thing nam'd . . 't is added , and the evening and the morning was made one day : in the originall text , and the evening was made and the morning was made , or , the evening was and the morning was . from which phrase 't is understood , that this motion had , for its term whence , the evening , and for its term whether , the morning ; and consequently , that the motion was made in a subject to which it agrees to have evening and morning , that is , in the earth ; and that it was from west to east , that is , towards the light. . again , and god said , let there be a firmament in the midst of the waters , and let it divide the waters from the waters : in the hebrew , an expansion . either word is properly taken , since it was a space unpassable for its vastnesse and expansion , and , by consequence , fixed , and fixing the division of the waters . . but those words in the midst of the waters are to be noted ; which teach , that no substance was made a new , but only between the waters and the waters : which is evident , too , from the word , heaven ; which name he gave the firmament ; by which very word , 't is express'd , that , before , god created the heaven . the etymology also of the word is to be noted ; which , both in the hebrew and greek idiom , signifies as much as whence the waters , or , whence or where it drops : that it may be evidenc'd , even from the name , that the aire it self is the firmament . chap. v. a philosophicall discourse of the vvorks of the other four days . . farther , by the operation of this vast fire , not only the water , but much of the earth , too , with the water must needs have been rais'd up . for , chymists know that the intense heat of fire can raise up and carry away crasse oyls and oyntments ; nay even salts and very gold it self . since , therefore , the earth , before the operation of light , was dissolv'd in minutest parts and dust , as , void of all moisture : it must needs be that the heat mix'd every where the water with earth ; and thus all muddy carry'd it up into the aire ; but , most of all , about those parts over which the fire perpendicularly hung . . whence , 't is plain , two effects must needs have risen : one , that the earth in that circle should become more hollowed and low then in the rest of its superficies ; the other , that the water , from the remoter places , should flow into these hollownesses : whether by the attraction of the fire ; or by naturall connection ; or by some power of gravity , which , through the operation of the fire , by little and little , attain'd a force . . 't is plain , therefore , that , since the motion of the earth was , of necessity , by the greatest circle : the earth , by the course of the foresaid causes , must be drain'd and dry'd first about the poles of that circle ; and the waters gathered together in the empty hollownesse under that circle . . i said , by the course of the foresaid causes : for , if we consider what was likely to be done by accident , this consequence will not be universally necessary . for , 't is clear , that the earth by the boyling of the water , being unequally mixt and remixt , with continuall agitation ; must , according to the law of contingency , have produc'd , by the meeting of different parts , as many kinds and species of earths , as we see diversities of fossils ; which we divide , generally , into four kinds , stones , metalls , mold , and concrete iuyces . . and , since , from the varieties , also , of those great parts of that masse now tempered with water , a notable variety must needs follow ; the earth , yet cover'd with waters , may easily here and there have boyl'd up into excrescencies ; as islands have often grown up in the sea. by this irregularity , therefore , some mountains growing , may have appear'd before the polar regions of the earth . . from the same principles , it follows , that the earth did not appear wholly squallid and desart , but already impregnated with the seeds of all things : nor with seeds only , but with plants , too ; those especially which either require or can endure more moisture ; the rest , by little and little , as the dryer earth grew more apt and fitly dispos'd for their birth , they , too , sprung out . . and , because an animal is nothing but a more-compounded plant : by the same reason , the earth , then most aptly tempered and dispos'd , brought forth perfect animals ; as it now being barrener , of its own accord , produces such as we call insecta , as mice and frogs , and sometimes new fashion'd animals . . but , because the waters must needs have been very muddy , even they , before the earth , must have sprung into animals fit to inhabit them ; viz. fishes , small and great ; as also into certain middle animals , which might fly up to the higher parts of the earth , that is birds : as , even now , we see all kind of birds that are bred of putrefaction , by the sea shores and lake's sides , grow out of the rottennesse of wood tempered with water . . 't was necessary , too , that , by the force of that mighty flame , parts of earth and water of a vast bulk , carry'd up above the aire , should , by naturall attraction and the power of the baking fire , coagulate into many vast bodies : whereof , some should more abound with fiery vertue , and therefore , both conceive and belch out abundance of flames ; so that being entirely lucid they should be apt to enlighten other bodies , too , within a fit distance : and , that others , lesse abounding with fiery parts , should be fit in a congruous order and method , to be concocted and enlightened by them ; and themselves , too , be able to reflect light from the former to the rest . . wherefore , were they set & moved in a convenient site to the earth now inhabited , they might alwaies more or lesse enlighten it : nor would there be any longer need of that vast light made by the angels . and this formation of things the aegyptians , aethiopians , empedocles and other naturall philosophers , as it were , by the conduct of nature , out of the very steps and order of generation which they still observ'd in nature , have emulated and attempted , though not throughly attain'd . chap. vi. an explication of genesis concerning the same . . the sacred commentaries , concerning these things , tell us thus , and god said , let the waters which are under the heaven be gathered together into one place , and let the dry land appear . here is the first mention made of gravity , whose effect is said to be , to congregate into one place : that we may see gravity is not a motion towards any particular site , but towards the unity of a body ; and that it was made out of the order of the universe now establisht , after that , between the acting light and the earth upon which it acted , a great distance full of aire was interpos'd , wherein the motion of things ascending and descending might be free . . iob . 't is said , that the sea flow'd , as it were , out of a womb ; whence 't is understood that the earth throughly moistned with water , sweat out on all sides , into the lower vaults , and increas'd the water , where , by the extreme force of the light , it had been too much suck'd out ; and so left the earth in its due temperament . whence ther 's evidenc'd , another cause , too , besides what we have explicated of the earths appearing , viz. because , by the permixtion of hot water , it swel'd into a far greater bulk . . it follows , and god call'd the dry , land , and the gathering together of the waters he call'd seas : for , it was not earth in the same sense wherein , at the beginning , 't was said god created the heaven and the earth ; for , there , the element of earth was call'd earth , but here a certain mixt body consisting of infinite variety . and , for the same cause , he call'd the firmament , heaven : for , at the beginning , heaven signifi'd aire and water in the purity of their natures ; but , here , a mixt body made of the elevation of the waters with the aire . . we understand farther , because the waters are commanded to be congregated into one place , and yet the effect is call'd seas ; the waters , which , from that mighty celestiall fire , had contracted saltnesse , though , to appearance , they possesse severall places , yet have a communion between themselves & truly constitute one place , though outwardly interrupted : as 't is evident of most of them , out of cosmographicall history . . it follows , and god said , let the earth bring forth the green herbs and which produces seed &c. whence 't is understood , that the generation of plants proceeded from the very springing fecundity of the earth , through the activity of so much heat ; without any extraordinary and miraculous concourse of god. for , if , in fifteen daies , plants ripen under the equator , which , with us , require a three moneths space for their generation ; what doubt , but , much more copiously and sooner they started out of the womb of the earth justly tempered by the operation of angels ? . nor need we believe , because the plants were perfect , therefore oaks and such like trees must have been at the full strength which they attain not under an intire age : for , it suffices , that the barren trees yielded shade and the fruitfull their fruits , against the sixth day . . the text goes on , let there be lights in the firmament of heaven , and let them divide the day and the night . and , even from hence , 't is evident that the office of light created the first day , was to dry the earth ; which being done , there was no longer need of so mighty a fire , and therefore the angels ceas'd from that operation . . there appears , again , the difference between that light and the sun : for the sun is not call'd light , but a light'ner , as a candle or a torch , wherein one part is flame and another fuel of the flame , or that yields the light . it appears , therefore , that the sun is a concrete of combustible matter , and a certain vulcanian globe all over full of pits vomiting flames : and , that it receiv'd the office of the former light , which was to divide between the day and the night . . but , in that 't is said , in the firmament of heaven ( the originall expression has it , in the expansion of heaven , or of that whence the waters ) 't is evident , these lights were plac'd in the aire ; and that ther 's no difference of nature between the firmament wherein the stars , and that wherein the clouds and birds are , and , consequently , that neither are there any sphears in which the fixed stars should be , but they are mov'd as fishes in the water . . upon which grounds , 't will not be hard to believe them made of waters rais'd up out of the earth ; as the or psalm clearly teaches : for , where our text has it , who covers with waters its upper parts , ( viz. of heaven ) , the hebrew has , who framest its chambers of waters : chambers are lodgings or abiding places aloft ; the stars therefore ( if indeed there are any people in them ) are elegantly call'd the chambers of heaven : and they are said to be fram'd of water , that is , built and compacted ; the watry parts , commixt with which the terrestriall were rais'd up , partly being drain'd into the concavities , ( as we said concerning our sea ) , partly keeping a consistency about the globes to thicken the aire , partly remaining in them , for a due mixtion sake , according to the variety of the parts of the globes . . but , that the angels , which before kindled the light , were divided amongst the stars ; especially the suns ( whereof , 't is evident , there are many ) iob shews by those words , when ask'd where wast thou when the morning stars marched triumphantly , or , exulted alike or together ; and all the sons of god sounded their trumpets ? that is , when the morning stars began to be mov'd ( as , in the psalm , 't is said of the sun , he rouz'd up himself as a giant , to run his course ) , that is , stars making morning or light ; to which conjoining the sons of god , he teaches that each of them had its angel , to excite their first motion , as it were sounding the alarm and giving the sign for motion , or , making the start and first impression . and this interpretation is best accommodated both to the hebrew words and to the matter whereof he spake : and the word , together , shews that , in one day they all began their motion . . the holy authour adds the end of these lights , that they might be eminent day and night , for so the originall propriety has it , where our text saies to rule over ; that is , that they might be very conspicuous : and , for signs , or , according to the force of the originall word , miracles or prodigies ; that is , that they might make men admire ; whence by little and little they might be elevated from terrestriall things , to know god and his works , and worship him . . lastly , for days and years . whence , 't is deduc'd , that the earth had been hitherto mov'd only about its own centre ; but , from thenceforward , began to be mov'd under the ecliptick ; viz. because the motion made by the first fire was so violent , that the waters were only drawn towards the light , or if any mov'd any other way , they were so few , that they were in no measure able to alter the course towards the light : but , the force of the sun being far lesse , did so make the waters move about the earth , that yet the impulse of the returning waters was notable ; whence the earth was mov'd about the sun in a line mixt , in a manner , of a circular and a right . chap. vii . some animadversions about the text of the first chapter of genesis . . from the whole story 't is evident that our earth is situated in the very middle of the universe . for , since all the rest of the world was form'd by evaporation from the globe whereof our earth was the centre ; & this , by fire intermediate between the earth & the other parts of the world : 't is evident , that the rest of the world is , with a certain equality , remote from it , and consequently , that it is plac'd in the midst . . which i would not have so understood , as if the centre of the earth were the very middle point ; but , that the great orbe , ( that is , all that orbe , which the earth makes with its circle about the sun ) has the notion of a centre : for , that it scarce makes a visible magnitude , in respect of the rest of the world , astronomers find by experience . . adde to this a conjecture from the phaenomena's . for , the zodiack is fuller of great and conspicuous stars then the other parts of the heavens ; as it must of necessity have happened , if the world began , after the manner we have explicated : besides , of all those stars which are illuminated from our sun , the earth alone is carry'd under the ecliptick , that is , through the middle of the very zodiack , to whose course the rest seem to yield and give place . . in the middle , between the generation of plants and animals , the celestiall bodies are reck'ned : because they are compacted of the crassest evaporations ; and therefore , ought not to be counted , 'till the earth had already shew'd it self , wherewith the generation of plants was conjoyn'd ; but , before animals , because they are not animated themselves , but are only for animated things : and , because they are adventitious to the earth , as helps ; before that animals were created , but especially man , for whom the earth was chiefly made , ( who , yet , is but a kind of animal , and therefore ought to be generated together with the rest ) , 't was necessary a habitation should be prepar'd , and consequently , furnisht with lights . . from the same order 't is deduc'd , that plants are not said to be animated or living , in the same sense as animals : since animals have in themselves the principle of their encreasing ; but plants are fill'd from without , from the order of the universe . . now , three things are to be remark'd concerning the explicated texts . first , that god saw all things good , besides the firmament and man : the reason whereof is , for the firmament , that it had only the notion of a place , and ( the stars not being yet created ) remain'd imperfect ; whereas the name of good signifies perfection : but man was the complement of all , and therefore , not in any speciall regard , but , looking upon the whole , he 's comprehended in this , that all things were very good . . the second is , why god , of all others should name day and night , the firmament , the land and seas , and lastly man ; but none of the rest ? the reason is , because , of those things that are made , some belong to the universe as formall parts , that is , without which 't is no longer a vniverse ; others , as materiall parts , which may be chang'd without the destruction of the universe : the first god nam'd , that is , fixt and establisht their nature ; the rest he omitted , as mutable . . the third is , why god bless'd only the fishes , birds and man ; and not the plants nor animals ? the reason is , because the blessing was to fill the earth and the sea : and , if he had commanded the trees or animals to fill the earth , there had been no room for man : these therefore were to encrease to such a degree only ; whence , otherwhere , god said to his people , that , by little and little , he would destroy their enemies , least the beasts should be multiply'd against them ; and 't is a saying , too , amongst us , concerning domestick animals , that 't is a good land which nourishes more men then beasts : but , because the sea was not the habitation of men , 't was said to fishes , that they should multiply without any other measure then that of the sea it self ; and the same reason is of birds in the aire . . farther , we have the reason why the creation of the world was distinguisht by days . for , since all these works were perfected by means of fire or the sun's heat ; and that , not in one quarter only , but over the whole globe of the earth : by consequence , the whole orbe of the earth was intirely turn'd to the light , whilst every thing was made ; now , we call a day an entire conversion of the earth to the sun. . it appears , too , that these days were unequall . for , since the globe which was to be turn'd , at the beginning was vast ( for water and earth were created of such a bulk , that all the stars might be made out of them ) ; 't is plain it was a mighty masse , and not to be entirely converted to the light under a long time . . the first three days , therefore , were very long , and the following still shorter then the former : but the later three were shorter and like ours or little longer ; so that an animal , at least in three of those days , might be brought to a congruous bignesse , a fish in two ; but the plants , even before the earth was altogether dry'd , already sprung up . . but , 't was necessary that those things which could not be produc'd at the same time and together , should be made in severall days : wherefore , three days were assign'd for constituting the orbe , other three for its adorning : and for establishing the firmament , viz. that vehement sucking out and elevating of the vapours , the second day ; the first having been spent in acquiring , as it were , velocity ; but the third day finisht the work ▪ that we might look upon these three days , as it were , the beginning , middle , and end . . in like manner , because some space was to be allow'd for breeding the fish , the first day is assign'd to the stars ; in which whatever was to be wrought ( at least , in respect to us ) requir'd nothing but their being show'n in the firmament , which is ▪ perfected in once turning about : and , because the procreation of the water is more abundant and quick , then that of the earth ; the generation of fishes is plac'd between that of the stars and animals . and thus , the necessity of twice three days is resolv'd . chap. viii . a naturall discourse of the creation of man. . but , because all these things consisted in motion , nor could sustain the proper notion of an end , 't was necessary a creature should be made , which should so transcend and grow above motion , as that , yet its beginning should be in motion : which , because , according to its form it exceeded motion and matter , a pure and , as it were , casuall heap of physicall indivisibles , and a mixtion otherwise then particularly artificiall could not frame . . a body , therefore , by angelicall hands , was form'd , which god alone , beyond the power of angels , could effectively animate ; and so , by their joynt-labour , man was made : with that capacity of body and , particularly , of brain , which should be most fit to polish his life conformably to nature , according to the conditions of the time wherein he was set . . in a little while , therefore , beholding all kind of plants , as also of animals and birds , he learnt the nature of things : but , when he would have told his thoughts in words ; there was nothing among them all which could apprehend or answer him . falling asleep , therefore , with much sollicitude , god made a woman to spring out of his side : to whom , at first sight ; the man joynd himself with extreme love ; and taught her which fruits were wholesome , which noxious and unwholesome . . she , believing her husband , but not knowing , her self , as he did ; being overcome with the deliciousnesse of a certain fruit provocative to lust , both eat her self & gave it to her too-uxorious husband : whereupon , being out of countenance with the swelling of their naturall parts rais'd without their consent , they sought for coverings . . mean time , by the command of god , the sun , raising the wind and the flux of the sea , turn'd the earth aside , which before had its axes direct and even with those of the ecliptick ; and spoil'd the country where man liv'd , of all its beauty : and introducing colds , brought in the mortall state of the world : and man was forc'd to guard himself with garments . chap. ix . an explication of genesis , concerning the creation of man. . these things are dictated out of nature ; concerning which , ther 's an ampler relation out of the sacred records . for first , god is said to have spoken thus to the angels , let us make man to our image and similitude : the word , let us make , signifies a speciall concourse of god and not a generall only , as to the other things . . an image differs from a similitude , in that an image speaks a relation of a thing either measur'd by or deriv'd from a pattern ; but , a similitude neither : besides , an image may be and , for the most part , is of a nature inferiour to its pattern ; but a similitude falls so far short of the perfection of a similitude , as it participates of another nature . man , therefore , was created to the image of god and to the similitude of angels ; according to that , and they shall be like the angels of god , and again , thou hast abas'd him a little lower then the angels . . the creation of man is describ'd thus , he form'd of the mud of the earth ; the primitive propriety has , thinking to make , or , to frame as a potter ; whereby is express'd , that the work of man was a greater task then that of other creatures , and that it specially requir'd the operation of an intelligence . where our text says , of the mud of the earth in the originall 't is , dust of red earth : now , of framable earths , that the red are the best ; pots for pleasure made of them witnesse , which yield a savoury rellish to the drinkers : and the force of the word dust is , to make us understand the earth was decocted into minutest parts ; for , almost in all arts , the more the matter is divided , the more exquisite the work proves . . it follows , and he breath'd into his face the breath of life : in which words , ther 's a clear expression of another operation , after the forming of his body ; to shew that the production of a rationall soul does not adequately proceed out of second causes . . and the words which follow , and man was made a living soul ▪ shew that there is no other but the rationall soul in man , since his vegetation proceeded out of that . that there are not , therefore , more subordinate forms in any matter , appears from the propriety of the sacred doctrine . . again , the holy writ says , god , therefore , took the man , and placed him in a paradise of pleasure , to work and keep it : and he commanded him , saying , of every tree , &c. though it be not expressely taught that the knowledge of god was infus'd into man ; yet , in that 't is said , he breath'd into his face , and again , that he took him and commanded him , 't is apparent enough , that god was first known to him , and , by god , his science was deriv'd to other things . for , his first object , at the opening his eyes , was his inspirer before his face : him , therefore , first he knew , ador'd , and lov'd ; and being shew'd by him the herbs and plants , the beasts and birds , he distinguish'd both the vertue & natures of each , & received them of him for his own use & service ; 't is plain , therefore , that he could not chuse but believe god's sayings , hope in his promises , & love him as his father . . that he learnt of god the vertue of herbs and plants , 't is evident , out of those words , thou shalt eat of every tree , &c. for , whilst he puts both an universality and an exception , he insinuates that adam knew both . moreover , those words , where he 's said to be plac'd in paradise , to work and keep it , ( which he could not doe , unlesse he knew the nature of plants , ) argue that he knew them . lastly , since 't is expressely said of the beasts and birds , that , by only seeing them , he throughly saw into their nature , in those words , to see what he would call them , and again , whatever adam call'd any living soul , that is its name ; since 't is most certain that the names were fitted ▪ to the natures of things , and consequently , were impos'd upon the knowledge of them : 't is clear that the inferiour natures , too , were as easily known to him . . the sacred authour adds , but to adam there was not found a helper like him : the primitive expression is , and to the man he found not a help as it were before him , or , as others explicate , as it were against him . it appears , therefore , that the woman was made , not out of the necessity of nature alone , but by the consent and will of adam : god governing man , a reasonable creature , by perswasion and induction , not by force and command ; that is , according to the nature which he had given him . . it appears , again , that the man was not only in his matter , but even in his mind , the authour and superiour and , as it were , the maker of the woman . . but , since adam had not yet felt the stings of the flesh ; neither knew he , as yet , the need of a woman , as woman : but only he desir'd one to discourse with , to whom he might declare his knowledge , and conferre about his doubts . this is that which was so grievous to the man , that god said , 't was not good for him to be alone ; and provided , not only for the present but for ever , that he should have such as he might teach and converse with . . nor makes it against this , that a man may seem more proper for the conversation of a man : for 't is not true , neither in regard of his mind , nor of his body : for , 't is known , that , as to his body , a man chuses to converse with the beauteous , and beauty is proper to women ( as they are condistinguisht to men ) : and , as for the mind , a knower chuses to converse with one that will learn & acquiesce , rather then one that will be refractory ; but women are more credulous and obedient then men : and , in respect to both body and mind , the conversation is more sweet and agreeable with such as reciprocate love ; but women are more obnoxious to love then men. . and that she was requir'd for conversation , the very genuine expression shews , in those words , a help , as it were , against him : for , since the countenances of those that talk together are mutually turn'd towards one another ; and man is made to be mov'd forward ; it appears , that the faces of those that discourse together are , as it were , of entrers by opposite and contrary ways , and consequently , the faces themselves , according to the same line , are opposite and contrary . such a help , therefore , was not found amongst all the animals : whence , 't was ill with adam . chap. x. an explication of the same , concerning the creation of woman . . god , therefore , cast ( the holy text proceeds ) a sleep upon adam : the propriety is , and he made a sleep fall : for , sleep begins from the brain and the head , & descends upon the rest of the members : as also , the cold of the night ( which proceeds from vapours that , having been rais'd up high by the sun and , refrigerated by its departure , descend ) is a cause of sleep : in both respects , therefore , 't is more aptly express'd he made fall , then he cast . . moreover , both sopor and the primitive word expresse a deep sleep and like to a lethargy : the septuagint interprets it , an ecstasy ; which so binds up the senses , that the ecstatick person cannot feel any , under the intensest , pain . . now , 't is easie to observe , that this sleep , at least in part , proceeded from the former great contention and travail of his mind to discern the natures of all animals , and from his pensivenesse that he found not his comfort or satisfaction in them all . . adam lay down , therefore , on his right side : for aristotle teaches , that this posture is the aptest for sleeping . and what did god ? he took ( says the holy writ ) one of his ribs , and fill'd up flesh for it : in the hebrew , the letter is more obscure , but thus , with propriety , 't is express'd , and he took one of his sides ; and shut up flesh under it ; and built the side , which he had taken from the man , into a woman . the word which we have express'd by he took is very large , and includes whatever manner of taking , for example , to lay hold on ; and the word which we have interpreted he shut up , is taken largely , too , for he compass'd about : the very letter therefore , in fine , yields this sense , god took to him one of adam's sides and encompass'd it with flesh , and built , that is , fram'd or erected it into a woman : so that the sense may be , that god multiply'd the flesh about one of his sides , and the flesh or side already swollen he , by little and little , distributed and fashion'd into a woman ; so that , the woman may seem to have proceeded out of the man , as a bough out of the trunk . . for , as the sun drawing up the moisture of the earth into the trunk fix'd in the earth , by percolation through the substance of the trunk , makes the moisture assume the nature of the tree , and increase the trunk , & rise up and be distributed into parts befitting the intire plant : so god , straining that sleepy humour through the side of adam , first made the side swell out with a great deal of flesh ▪ then be distributed into all the similary parts , and lastly into the dissimilary . . and , besides that this sense is very apt to the words , nothing is more agreeable to the nature of things . for , to the three degrees of man , the triple procreation corresponds ; adam , as a mixtum , was form'd ; eve , as a plant , grew out of adam ; abel , as an animal , was born of animals . besides , reason requires , that , since in adam there was the next & immediate matter of the woman , she should not be made out of any other then that : but , like is made out of like by accretion , according to nature . moreover , she is produc'd out of his side , because ther 's both flesh and bone and , through the nearnesse of the bowells , especially of the heart to the left side , it necessarily participates more of the vegetative vertue then any other member of the exteriour cataphragm . bringing to , here , is , clearly , to be interpreted , not for a translation from place to place ; but , for an oblation or exhibition . it follows in the divine history , this , now , is bone of my bones ; and for , now , the hebrews read this time : the force of both terms is the same , viz. that god otherwhiles offered him incongruous things ; but , now , something agreeable , and naturall . . under the name of bone and flesh the whole body is understood ; that is , the rest of the similary parts whereof a man is compacted . . she shall be call'd , &c. since what adam call'd every living soul , that is its name , the term given the woman must signify the proper notion of woman ; which is desum'd , not from her matter , but from her form and end : how comes , therefore , this name which adam impos'd ( even himself being witnesse ) to be taken from the matter ? it must be said , that those words , because she is taken out of man , do not signifie because she is made of man , which is common with her to lice and fleas ; but , because she is of the same nature with man. and , 't is to be observ'd , that the hebrew word signifies prince , or chief , or fundamentall , or subsistent : so that the sense may be , because she is of the nature of man , to excell the animals as he himself . . adam says farther , that they should be two in one flesh , or , as the primitive reading has it , into one flesh , viz. three manner of ways ; in the issue , which proceeds from both ; in the woman , since physicians affirm that the seed of the man disappears , being transum'd into the flesh of the woman ; and lastly , by consent for copulation : for , since that is perfect which is apt to make its like , neither the man nor the woman , without one another , is perfect ; both , therefore , as they combine to the production of their like , integrate one , physically-perfect , animal . . whence , 't is understood , why god neither said let woman be made , nor , let us make woman ; but , i will make ; for , so , the truth of the holy language has it : namely , because the mixtion of the elements into flesh , which was the proper action of the angels , was already done in the forming of adam ; and the augmentation of that exceeded not the power of adam's nature ; the rest , therefore , was only the concreation of a soul , which belong'd to god alone . chap. xi . an explication of genesis concerning paradise . . thus , man was entirely perfected : what misfortunes afterward befell him let 's enquire out of the mysticall book . it says , therefore , and the lord god had planted a paradise of pleasure from the beginning , wherein he put the man whom he had formed : the hebrews read a garden , which says the same thing ; but , what is signifi'd by these names must be sought out of the description . first of all , therefore , we are taught , that , out of the ground , there was born in it every tree fair to sight and sweet to eat ; which , from the description of the third day , 't is clear , agrees to the whole earth . . the next is , that the tree of life , and the tree of the science of good and evil ( as eve witnesses ) were in the middle of paradise ; now , 't is an hebrew propriety to say in the middle , for that which is among or within : the letter has it thus , and god made to spring out of the earth every tree , fair to sight and sweet to eat ; the tree also , of life in the middle of paradise , and the tree of the science of good and evil : that is , all kind of trees pleasant to sight and tast ; among which were good trees and conducing to life , and some which were apt to make a man experience evil things as well as good . . 't is added , that a river went out from the place of pleasure ; the force of the hebrew word is , out of pleasure ; to water paradise , & thence 't is divided into four heads ; in the hebrew , and from there ( that is , already in paradise ) 't is divided and is into four heads . the sense is , that out of the abundance and fertility of the earth , water sprung in four heads or great rivers : for 't is incongruous that one river divided into more , should be said divided into heads , but into branches or arms ; nor are there any where found appliably to paradise , four rivers , which can ever be conjectur'd to have flow'd from one head ; nor can any other place of pleasure or a more fertile place then paradise be imagin'd , from whence this river should flow to water paradise . . and what is here call'd fertility and abundance , is describ'd to have agreed to the whole earth , at that time ; it being said , that a fountain ascended out of the earth , watring the whole superficies of the earth : where , the native text , in stead of fountain , has a vapour ; whereof the book of wisdome seems to speak , when it saies that she cover'd the whole earth as with a mist ; and , perhaps , the psalmist , when , after the forming of the earth , he subjoyns , the abysse is the vestment of its cloathing , waters shall stand upon the mountains . . an example , too , of such like we have in some very hot and moist regions ; in one of the canaries , in the island of saint thomas , and some others ; that there issues a vapour out of the earth , which being refrigerated with the shadow of the trees , descends in a rain and feeds the fountains and rivers . and , it cannot be , but , out of the earth yet moist , by the power of the sun , for some time , such a vapour must issue and water the earth , and be deriv'd into rivers . . but , now , the enumeration of the rivers makes the matter manifest : for it takes the four greatest rivers known to the hebrews , and which wash'd the whole world that they knew ; and saies that paradise was watred by them . but , those that labour to derive these names to other rivers , run into mere and incoherent conjectures . . the scripture adds , the lord god took , therefore , the man and put him in the paradise of pleasure , that he should work and keep it . the hebrew word for , he took , is the same with that above , when we spake of adam's side , and signifies the same as , take in the largest sense ; nor , in this place , does it expresse any other thing then an application or conjunction of god to adam , and not a locall carrying , as , before , 't is said of the word he brought . but 't is said above to adam , that he should take the earth for his matter to work on , and fill it : we have it , therefore , that the garden which adam was to cultivate and inhabite , is the same which he was commanded to fill and subject ; and whereof 't is said that , as yet , there was not the man to labour it , but a vapour ascended and watred its universall superficies . adde to these , that the whole earth was cursed ; that the whole , before the curse , was created for adam and his issue ; which , in a garden only , could not have had room enough . . consider the honour of husbandry : both that , of all the mechanicks , 't is the work that 's most proper to mankind : and 't is a keeping or preserving of the earth ; for the earth grows better by cultivation , but uncultivated it grows barren & , as it were , perishes . . besides this precept , god added another positive one for nourishing himself , and a negative one for not killing himself by intemperancy . chap. xii . the history of adam's fall , out of genesis . . the divine authour begins the following history , saying , moreover , the serpent was more crafty then all the living creatures of the earth : the word which corresponds to serpent , in the originall , is deriv'd from a verb which signifies to observe or to pry into secrets ; wherefore , à priori , it signifies , an observer , a lier in wait and what in the gospell , the tempter : and where the latine interpreter puts all living creatures , the sacred authour uses a very large word which comprehends man too : so that the sense may be , the tempter was craftier even then man himself ; as , also , it appear'd by the event . . he came , therefore , to the woman and said , why has god commanded you , &c. in the originall letter , even that god has said : as if it should say , was it not enough for god to have oblig'd you to keep his garden , but even must he not-permit you to eat ? to whom the woman answer'd , yes , we do eat of the rest , but should we eat of the tree of the knowledge of good and evil , we should die . 't is evident , therefore , this command was given by god , not as out of power and prerogative , but for the good of those to whom 't was given , and man is govern'd by god alwaies for the good of man himself . . the tempter therefore reply's again , you shall not die , but you shall be like gods : the analogy of the two temptations is to be noted , say that these stones be made bread , and , he forbids you to eat : he has commanded his angels concerning thee , and , ye shall not die : lastly , all these will i give thee , and , ye shall be like gods. . 't is added , the woman , therefore , saw that the tree was good to eat , and fair and delightfull to behold , &c. the tree is put for the apple ; or , certainly , in respect of the apple , these things agreed to it . and whereas 't is said , she saw the apple to be sweet to the tast , or good for food , as the originall reading has it ; it argues that the woman , too , to some degree , from the sight of plants , especially the earnest looking on them , knew their natures . and the authour , instead of this , delightfull to behold , has , desir'd to look earnestly upon , or , to understand ; and the sense is , that the woman saw her appetite so to have encreas'd , that she could not turn away her eyes : or else the word saw signifies consider'd ; and the sense will be , she consider'd that the apple was desirable for the knowledge that would follow it , upon the tempter's words . . the woman , therefore , eat , and gave , too , to the man ; who was not deceiv'd , that is , did not eat upon a false perswasion , but , as 't is subjoyn'd , obey'd the voice of his wife : for , alas ! he was effeminate , and durst not , through excesse of love , oppose his wife . . 't is collected out of the circumstances , that the tempter or lier-in-wait had observ'd the woman absent from her husband , near the forbidden tree , at the hour when her appetite to eat made way for his treacheries . . but , let us see the effect . the sacred text , therefore , saies , that the eyes of them both were opened and they knew they were naked . but 't is plain that , not presently upon their eating , but after some time ( suppose , when , by concoction , the poison of the apple was digested into their bowells , ) this effect happened : for , if , immediately as soon as the woman had eaten , her eyes had been opened , she would have blusht and not dar'd to appear before her husband ; or , at least , being sollicitous and troubled about the change she felt , she would have told it him . . but , how their eyes were opened and how they knew themselves to be naked , appears by the following action , that they made themselves aprons or girdles , to cover with them the parts destin'd for generation . evident , therefore , 't is that , by their eating the apple , their flesh rose and was mov'd without their consent . the effect , therefore , of the apple was immediately to provoke lust ; & , through the intoxication , as it were , of luxury , to shake off the use or command of reason . . the very description , too , of the fruit insinuates it to have this vertue . for , physicians say that sweet is primely nutritive , as consisting of hot and moist connaturall to the animal ; and that , whatever nourishes does it , in as much as 't is sweet : good , therefore , for food ( when 't is spoken by way of eminency ) is , what is very nutritive : but seed is made of the superfluity of the nourishment : good , therefore , to the tast , or , for food , shews it was provokative of lust . the splendour , too , of colour , since it proceeds out of a good commixtion of subtle and oily parts , is apt to follow the sweetnesse . chap. xiii . of the punishment of our first parents : out of the same . . it follows in the history , and when they had heard the voice of the lord god walking in paradise , at the cool , after noon ; the hebrew saies , when they had heard the noise of him coming into the garden at the aspiring of the day , or day-break : and the sense is , that god , in the morning , with the cool aire which goes before or accompanies the sun , came into the garden ; namely , to be ador'd by adam : whence , when adam appear'd not , but had hidden himself in the middle of the trees of paradise , that is , among the trees , which were very thick , he call'd him . and this sense seems the better : for , what could be the end why god should appear a-walking ? besides , that the cool of the day is better understood the morning then the evening ; whence , in the canticles , 't is said of the morning , 'till the day aspire and the shadows be inclin'd : for , not that which is done by the day retiring , but what the day brings along with it , is properly attributed to the day . . 't is added , how god examin'd adam and eve ; but he punisht the tempter without an examen , as being a profess'd enemy and of a known malice . the first punishment is , that he should be cursed of all living creatures ; for so , the primitive expression has it , not among living creatures . the second the latine interpreter puts to be , thou shalt go upon thy breast : but the hebrew word derives from a verb which signifies to sigh , or , to burst out , as it were , the issue out of one in travail ; so that , the sense may be , in sighing and grief as of one in travail , that is , thy whole life and all thy actions shall be full of grief and pain . . the third is , thou shalt eat earth , but the hebrew saies , thou shalt destroy dust all the daies of thy life ; which seems the better ; for serpents corrupt the earth with their breath , but do not eat it , that i ever read . nor hinders it , that , in isaiah we read , to the serpent dust is his bread : for , that was not to be in the holy mountain , which was the effect of malediction : better , therefore , 't is explicated , to the serpent ashes to warm him ; that is , the serpent shall be no longer an enemy to man , but shall dwell in the chimnies , ( as 't is read of some domesticall ones ) ; whence , 't is immediately subjoyn'd , they shall not hurt nor kill in all my holy mountain . in the text of genesis , the same word is put for dust which was in the forming of man : that the sense may be , thy design shall not be against angels , like thy self ; but how thou maist undoe such as are made of earth . . out of what has been said concerning the tempter , it appears , ther 's no necessity of interpreting that the devil should have come to the woman by the means of a reall serpent , or in the figure of a serpent ; but in a form like that , in which he came to our lord christ : for , first , most of the things that are said agree not to a reall serpent ; viz. to be craftier then any living creature ; to be able to speak , without frighting the woman ; to speak not of things they saw , but of gods. . again , his being cursed of all living creatures , his being curst to eat earth , agree not to a reall serpent : and that one only thing which agrees , viz. to go in upon his breast ; since 't is a naturall manner of creeping , was had by creation . wherefore , the opinion of a serpent or a serpent's figure seems to have proceeded from the equivocation of the hebrew word , or , a metaphoricall use of a serpent for the devil . . the following prophesy , too , concerns the devil , not a serpent : for a serpent is no more an enemy to man then to the other animals ; but the devil is to christ ; and he bruises the heel of christ , in as much as he debauches and masters the lowest rank of christians , or the wicked ; christ too , breaks his head , both because he is to judge the angels , as also because he takes away the power the devil has in the world . . there follow , the evils which seize on the woman through sin ; that she should have more and harder labours ; that she should be under the power of her husband , and be oppress'd by him . and , that this violent subjection proceeds from sin , is plain enough ; since it rises from the indiscretion of both parties : bringing forth , also , with pain , evidently , proceeds from the same ; for , even yet , many women under the aequator , bring forth with little or no pain : now , the pain in travail comes through the drynesse of the members , by reason whereof the bone cannot give place , which is easily conjectured to proceed from the intemperatenesse of the aire and of meats . . lastly , that her conceptions are more is manifest , in respect of abortions and imperfect conceptions : but , whether through the intemperancy of copulation ; or the shortnesse of the time of going with child , which , may be , should have been longer ; and lastly , whether , because in the immortall state of paradise there should not have been requisite so copious an issue , therefore the conceptions should have been fewer , 't is disputable . . among the maledictions of adam , the rest appear plainly to proceed from the sterility of the earth ; but this , that he should eat the herb of the field , seems , from the beginning , to have been indulg'd him as a blessing , & here 't is reputed amongst his punishments : but , the sense is , that he should be compell'd to lay up in barns the herbs of the field to eat ; because , sometimes , the earth should yield none . . moreover , those words , 'till thou returnest into the earth out of which thou art taken , &c. clearly shew that he should have been immortall ; that is , have liv'd a long time , and afterwards , not be devested but cloathed-over , as the apostle speaks . . it follows , how he was cast out of paradise ; and 't is said , that , adam being cast out , god plac'd , before the paradise of pleasure , a cherubim & a flaming and turning sword , to keep the way of the tree of life . to understand which , we must reflect upon the universall cause of the corruption of all things , especially of living creatures . and , because animals are cold in death , 't is plain , that cold is the cause of death ; whence , we see , that winter is , as it were , the old age of the year , the years , therefore , had continu'd in one state of heat and cold in paradise ; and to introduce winter , is to make life shorter , & to have brought death nearer . , the cause , therefore , of the variety of the year is the cause of death : and this , astronomers teach , happens , because the earth keeps not still it s same parts to the sun , or in that it conforms not its axis to the axis of the ecliptick , but alwaies turns it from the poles of the ecliptick to the poles of the aequator ; & this , naturalists teach us , happens through that motion , by which the flux of the sea turns the earth ; and , the flux of the sea , from a wind which the sun under the aequator raises . . let 's see what the sacred monuments expresse concerning this : first , therefore , they say , that which was to be done was , therefore , done , least , perhaps , he should reach out his hand and take of the tree of life , and eat , and live a full age , or a thousand years : whence , 't is evident , that the vertue of the tree of life was not wholy to exempt from death , but to deferre it and make to live in seculum , that is , a long time ; which vertue ther 's no doubt is taken away by the empairing of the fruits . . then , that which our translation saies before paradise , others render from the east to paradise . if , therefore , ( as we have said ) the whole earth was paradise , and the motion of the earth proceeds from the sun , the cause of the conversion of the earth is from the east , and , to be from the east is , to be before the earth and paradise . moreover , that which ours renders a cherubim and a flaming and turning sword , in the originall is a cherubim & the edge of a sword turning it self . the one phrase shews that the force of death proceeded from a cherubim by flames and fire ; and the other , by turning : now , that the sun's motion proceeds from a cherubim or an angel , metaphysicks demonstrate : if , therefore , that winding of the terrestriall axis to the poles of the aequator , be deriv'd from the sun ; and , from that , the nature of death , by the variation of light and heat ; is it not evident ( if a sword may signifie a killing power ) how a cherubim , with a flaming and turning sword , keeps the way to the tree of life , least man should live by it a full age . . and , he that thinks this interpretation , of a sword for a killing power , too hard ; let him remember the angel , in the threshing floor of ornam , holding a drawn sword to bring the plague upon jerusalem . let him consider , also , if the name of sword be taken materially , how disagreeable the narration will be : for , the angel should have been plac'd , not from the east , or , before paradise , but round about : nor would there be any need of a turning sword , but of a sharp one ; for , the angel could have turn'd it , as he pleas'd . . lastly , the cloathing of adam and his wife with coats made of skins , manifestly insinuates that the cold grew upon them ; the year , as it were , now inclining towards winter : whence , it seems , 't was autumn in that region where adam was created . yet , 't is not necessary , that god must have given them those coats of skins immediately upon the malediction , but after some time ; when , having done penance , they had sacrific'd beasts to god : with whose skins god cover'd them , not so much for their nakcdnesse sake , which was cover'd with aprons , as for the colds , and therefore they were made of skins with which beasts are kept warm . chap. xiv . of the evils deriv'd to posterity : out of the same . . none doubts , nor can , according to what we have said , but this state of infelicity and death is deriv'd to us , the posterity of adam , from his sin : but , what evil or corruption we derive , as to the mind , 't is to be consider'd . and , first , 't is evident , that the understanding of adam was most happy ; which so easily attain'd the knowledge of things , that , at first sight , he could impose significant names upon every one . . which is not so to be understood , that he perfectly saw through all things : for , from the deceipt of eve , and both their hiding themselves from the face of god , 't is clear , their discourse was short and imperfect at that time . nor , is it believ'd that they lost their naturall force : wherefore , by nature , their understanding was so hinderable by passion , as to bring them to such inconsideration . . but , we read , too , that they were naked , and blusht not before their sin , but afterwards : whence , we understand , there were before no inordinate motions in them , since , in lust , the most vehement kind , they had none . . now , for man to have no inordinate motions in him , may happen two waies : one , that we should assert there were indeed such motions , but , as it were , rooted out by a long use and exercise of vertues : another way , that we should imagine his nature so temperate and equally ballanc'd between passions ; that it should submit it self intirely to reason , out of its own equability , and not out of an acquir'd dominion of reason . . and , since god might have created man in the perfection of either of these ; if we consider the circumstance of the newnesse of nature , we shall rather assent to the later description : for the former state is of one already proceeded from power to act ; but this later is a certain species of potentiality , or of man , as to his soul , existing in power : that , the state of man grown good , of evil that he was ; this , of man not yet knowing good and evil , or , untaught by experience : to that man 't is now hard to sin , and certain that he will not be separated from the love of christ ; to this , 't is easie not-to-sin , but sin is rather unknown to him then hard , and consequently , his entrance to good or evil is doubtfull : that state is more establisht in the brain through the exercise of reason ; this more in the body , through the goodnesse of its temperature ; whence , this is more propagable to his issue , though that be so , too , in some degree . . since , therefore , philosophy teaches , that even that complexion of nature , which rises from acquir'd habits and exercise , is apt to be deriv'd to the issue ; much more that , which was by nature planted in adam , would have pass'd into his posterity . his children , therefore , had he not sin'd , would have attain'd , from their origin , a certain equability of passions , whereby they would have grown easily obedient to reason ; or rather , they would have had no passion more vehement then was just fit , so that they would have felt no difficulty in following right reason : from which disposition he seems not to have st. bernard ▪ been far , of whom 't is wonderfully said , that adam , in him , had not sin'd . . whence , the perverse motion of the will in our first parents , was apt to proceed only from extrinsecall sollicitation : so , we see , in the answer of eve , that she was content with the command ; 'till the devil , proposing a shew of fallacious reason , which she could not see through , had fastened , as it were , her mind to the delectable form of the apple before her ; by which fastening , that naturall equality was corrupted : which , too , in like manner , happened to adam , through his amorous fixednesse to his wife ; as may be collected out of his words , wherein ther 's no praising of god the giver , but only a commemoration of the lovelinesse of the woman . 't is evident , therefore , that the naturall principles of motion and passion were corrupted in both our parents ; and so , in generation , an inequality was deriv'd to their issue : not one equall to theirs , but one far greater ; it being now corrupted from the change of site to the heavens , and the quality of the aire and food : and so , irrecoverably their posterity drew from the womb of their mother an origin or inclination to sin . . which negation of equability , because 't is in a subject to which an equality is due by its creation , attains the nature of a privation : and , because the guilt of adam is in it , or , because we derive our origin from him , 't is , therefore , call'd original , not formall , sin : and , because 't is impossible that man , infected with this , can live without sin , by the strength of nature & without new grace ; therefore nature is call'd the slave of sin , and given up into slavery to the devil . but , whether originall sin comprehends , besides an indisposition of the sensitive soul , a privation of charity consequent from it , in the issue , ( because ther 's nothing offer'd out of our text , spoken concerning that matter ) i leave to the curious . . it suffices us that , out of what has been said , it may be understood , how originall sin is singular in every one , how 't is deriv'd by generation , and how it proceeds from the fault of another . . of these things that have been said , i know not whether we have not , in some measure , an example in cain and abel : cain being conceiv'd in sin , ( perhaps , the very night after eating the forbidden fruit , before god , by punishment , had provok'd them to penance ) ; abel , in the time of penance : whence , cain contracted , in the conception , his mothers envy against god ; abel her humility and piety ; wherefore , what our interpreter renders i have possest a man by god , may be more truly translated , i have loved a man against god. chap. xv. of the propagation of mankind : out of the same . . after the death of his brother , cain departed into the barrener parts ( as appears , from his curse ) : and , this was the first occasion of filling the severall quarters of the earth . and , he is said to have sojourn'd towards the east from eden ; or rather , towards the west , for the originall letter has it , he sat down in a strange country before eden , that is , he dwelt in a far country before eden , that is , to which the face of eden is turn'd , ( adam and his family being suppos'd to look after him when he went from them ) , that is , to the west , or , having eden eastward . now eden seems to be call'd that country in which adam dwelt , in memory of the pleasure he had there . . and the sacred authour prosecutes the generations of cain to the seventh descent ; and tels us the cities that were built , and the arts both for use and pleasure invented in them . but , how many years each generation contain'd , he mentions not : but , 't is likely , they were shorter then the generations assign'd to seth ; whence , in the time of enos ( which extends to about a thousand years after the nativity of henoch , the first-born of cain ) the children of adam , on cain's side , may have been exceedingly multiply'd , and that hap'ned which is written , that , in his time , the invocation of the name of the lord was polluted , viz. in most of the posterity of seth and adam , through their marriages with the daughters of cain . . for , since the sons of seth , and the rest that liv'd with adam , may seem to have follow'd a pastorall life , and to have liv'd temperately ; but the daughters of cain to have been delicate and luxurious : there appears on the male's side strength and virility ; and , on the female's , abundance of moisture , figurable by heat ; whence , 't is consonant , that a vast and robust issue was born out of their conjunction . and , out of confidence of their great forces , men are prone to fall to injuring and oppressing the weak : whence , lamech call'd it a consolation , to kill all man-kind ; according to the by-word that saies , 't is better to be alone then ill accompanied . . but , whether they were of a huge stature of body , such as we call giants , appears not out of the sacred history ; where nothing else is said , but that they were oppressours , strong , and such as got themselves a name , or fame . chap. xvi . of the floud : out of the same . . when , therefore , they were impenitent , whilst noe built the ark , to save the few just , that is , eight persons ; the waters began to poure down upon the earth ; which genesis describing , saies thus . such a year , moneth , and day , all the fountains of the great abysse were broken up , and the cataracts of heaven were opened , & there was made a rain upon the earth fourty daies and fourty nights . the originall text , for were broken up , has , slit themselves , and , for cataracts , a word which signifies occult cavities , from a word which imports as much as , to ly in wait ; as if it would say , that the repositories of heaven , wherein god had plac'd , as it were , waters in ambush , were opened . . to these is to be added that place , in the second of peter , wherein 't is said , there was of old a heaven and an earth , of waters and by waters consisting , by the word of god , by which that world , then , overflow●d with waters , perished : but , it cannot be understood , as if the earth consisted of water ; which is no where written , but rather the contrary , viz. that the earth was created together with the waters : the sense , therefore , is , that heaven consists of waters , the earth by waters , to wit , mingled together by that mighty fire ( whereof largely above ) : consisting , therefore , is refer'd to both , though it be construed with the later . . it saies , then , that the old world was overflow'd by these two waters ; whence , 't is evident , those are distinct waters which are , here , call'd the cataracts of heaven , from those call'd the fountains of the great abysse . now , we find no more about heaven , after the fourth day , but that , a vapour ascended from the earth to water the universall face of the earth : and , that the earth was cover'd with a mist : and as much concerning the sea ; iob speaking in the person of god , when i put it on a cloud for its vestment , & wrapt it in darknesse as in the cloaths of infancy . for , these signifie , that the aire was thick , and misty ; there sweating , by the suns force , as it were , a perpetuall watry humour out of the earth , whose thinner parts were of necessity continually rais'd up into clouds : which could not fall , for a time , whilst the aire , quite up to them , was thick and as heavy as they : but , after , the earth being dry'd , the aire between the earth and the clouds , became it self , too , more dry and subtile , the terrestriall humidity being spent ; then , at length , with a mighty vehemence , the long-treasur'd-up waters in the clouds descended ; in such abundance , that the fountains which broke out from the more eminent parts of the earth were so over-charg'd , they slit their channels and , with open torrents , roul'd into the rivers , and they , oreflowing their banks , all at once into the sea. thus , therefore , by the waters whereof the former heavens consisted , that is , the midst between the earth and the stars , and by which the earth consisted , viz. which lay hid in its bowels , the whole earth was o'reflow'd in the time of noe. . and the history tells , that the waters rose fifteen cubits above the tops of the mountains : now , 't is not incredible that some men were so tall ; so that this quantity of water was altogether necessary ; nay , if there had been strong trees upon the highest mountains , which could have resisted the water , this proportion of water had been lesse then needed . . for , since , after the deluge , og may seem to have been nine cubits high ; before the deluge , 't is credible enough , there were some near fifteen : though , to perswade one's self , there were ever men of that vastness which is attributed to the cyclops , and certain reliques found in the new world , there needs a great faith ; for , these stories depend on uncertain memories , or on conjectures of men talking , according to likely-hood , of old bones . . but , to return to the abundance of the waters . the severer mathematicians , now adaies , do not believe any mountain to be higher , perpendicularly , then one italian mile : nor need we believe the mountains , before the floud , were so high as they are now the vallies are hollowed deeper with continuall rains. if , therefore , fifteen cubits be abated from the highest mountains , make account the water rose a mile , perpendicular , about the earth . . whence , 't will be deduc'd , that about an equall proportion of water out of the clouds and out of the bowels of the earth concurr'd to the deluge : for , if a pail set in the open aire in a very violent rain , will be fill'd a cubits height in an hour ; in fourty daies and fourty nights , a continuall and vehement rain from all parts of the heavens , would o'reflow the whole earth little lesse then a thousand cubits high : as much , therefore , or more water was to be strein'd out of the earth , that the floud might rise to a thousand paces high . . which to render credible , reflect upon the artifice of husbandmen , not unusuall amongst us , by which they draw some feets depth of water over their barrener grounds ; with the weight whereof the superficies of the earth being loaded , is press'd down & constipated with the lower earth , & so fills those hollownesses into which the air 's entrance caus'd the barrennesse ; whereupon they are rendred fruitfull . from which experiment , 't is evident , that a huge weight of water brought upon the earth must compresse it , strein out the water which was hid in it , and represse its swelling ; and consequently , constipate the earth and force it into a lesser circle . since , therefore , the power of the deluge may easily be believ'd to have extended it self three miles perpendicular within the earth , ( for the sea is judg'd so deep , now , in the deepest parts ) : let the earth but have contracted it self one sixth part of those three miles , and you have water press'd out of its own bowels to cover it five hundred paces round about . we have , therefore , a fit proportion of water for so great an effect , if we can contrive whence so much water may have ascended into the clouds . . but , if the little lesse then two thousand years space be reflected on , in which the sun rais'd up perpetuall vapours to the very sphear of the moon , and perhaps higher ; and kept them there , by reason of the continuall thicknesse of that aire between the earth and heaven ▪ it will be easily credible , that there were clouds amass'd together enough to pour down fourty daies and nights violent rain ; which , we have said , is sufficient for the effect . chap. xvii . of the cessation of the deluge : out of the same . the inspired writer prosecutes the abatement of the water ; which he divides into four parts : to the resting of the ark upon the mountains of armenia , a hundred and ten daies ; thence , 'till the appearing of the mountains tops , about seventy daies ; from those , to the time when the superficies of the earth shew'd it self ; and from thence , to the intire drynesse , almost as many daies as in he first part , divided almost equally . . the causes of so unequall decrease are two , deduc'd from the letter : a wind which god rais'd ; and a motion of the water , proceeding from the wind. as for the wind , 't is clear , when the sun began , now , to shine bright , the clouds being dispers'd , and there was nothing but water upon which it might act ; there could no other wind be rais'd , then such as , even now , we experience in that vast clime of the pacifick and atlantick seas : though we must needs think 't was far more both vehement and ample , when there were no shores at all whence contrary winds might blow , and contract its bounds . . the first part , therefore , of the abatement was made by this wind , through the mediation of the sun , which turn'd the waters into wind : and the wind , now dry'd , dry'd the waters by adhesion , as we see it does linnen cloaths , by carrying away with it the watry parts . . and the ark is believed to have rested upon the highest mountain in those parts . the hebrews say , that it sunk twelve cubits into the water ; still , therefore , by this account , the water was twelve cubits above the neighbouring mountains : but , these cubits by reason of the former contraction of the sphear of the waters , were lesse , in proportion , then those whereof there were fifteen before above the highest mountains ; as also , then those which the water had abated , from the top of the highest mountain to the top of that upon which the ark rested : wherefore , to these cubits , about seventy daies are assign'd . . from the discovery of the mountain-tops , to the appearing of the earths superficies , about fifty five daies more are counted : both because every day the sphear became more contracted , and the sun more ardent through the reflection from the higher parts of the earth ; as also , because the motion of the water , now , concurr'd ; whereof the divine book says nothing but and the waters return'd from the earth , going and coming , and again , but the waters went , and decreased . there can be no doubt , but this motion of the waters , since it proceeded from the wind , which rose from the sun , follow'd , principally , its course , that is , was from east to west ; and consequently , that the water is said to have gone and come , because the water which was mov'd under the aequator , farther off from the aequator return'd , by the force of gravity ; because the water was lower in those parts out of which it had been expuls'd by the wind : and this , 'till the mountain tops appear'd , was regular ; but , afterwards , by incountring the mountains and higher parts of the earth , this course of the water , at least in those parts , was interrupted . . whence , ther 's no farther mention of it ; though its effect towards drying up the water began then to be greatest : for , by this flux of the water , the earth , by degrees , was heap'd up towards the mountains , and there was a more ample channell dig'd for the waters , especially in that part which was to remain cover'd with them . whence , the fourth book of esdras witnesses , that , at the creation of the world , there remain'd only a seventh part cover'd with waters ; but , now , cosmographers will have the superficies to be half sea. . moreover , by this agitation , if any cave remain'd empty within the earth , there was a passage opened to it for the waters . whence it appears , what became of such a mighty bulk of water : for no little part of it was consum'd by the sun in wind , and to condense the upper aire to that proportion which was convenient for the nature of things ; another part was swallow'd up into the cavities of the earth ; the rest , having dig'd it self a vast channell , remain'd in that part of the earth , which we , now , call sea. . but , i must not passe over this place , without advising that the cause of the flux and reflux of the sea is clearly taught to proceed from the wind , as 't is explicated in physicks , the scripture straight adding , and the waters return'd from the earth , going and coming , immediately after the bringing the spirit upon the earth . but , some may object , that , during the fourty daies rain , there was no such wind ; and consequently , no flux of the sea neither ; and , because the diurnall motion follows from that , neither can there have been daies and nights . . 't is answer'd , such vast clouds and rain could not happen without tempests ; and consequently , since this rain was regular , a regular wind , too , accompany'd it ; and this , according to the course of the sun , since the greatest heat is not to be expected but under the sun : the wind , therefore , was more vehement those fourty daies , to roul about such a masse of waters ; whence the equality of daies and nights may have been preserv'd either wholly or very near . 't is a sign , too , of a wind , that the ark is said to be carry'd upon the waters , and to have rested upon a mountain , whereas 't was made in a vally . . the sacred historian seems to add two other causes of the decrease of the waters , viz. the shutting up of the fountains of the abysse , and of the cataracts of heaven , or the prohibition of rain from heaven : but , this later cause is clearly an effect of the wind 's being calm'd and of the clouds being all spent , as already fallen down upon the earth : and the former is an effect of the drying of the mountains ; for because the mountains were dry'd , vapours began to ascend into their tops , which flow'd out in little channells and rivulets , as before the deluge : whence , it appears that their reading , too , who interpret it the fountains of the abysse were reveal'd , comes to the same thing . chap. xviii . of the covenant made vvith noe after the floud : out of the same . . at length , noe and his family being gone out of the ark , god made a covenant with them , that he would overwhelm the earth no more with waters : and plac'd for a sign of the covenant , his bow in the clouds . and that the rainbow is , indeed , a sign there shall be no deluge at that time , is evident from hence , that , unlesse the sun shine otherwhere , there appears no rainbow ; 't is clear , therefore , that there is not enough rain in the clouds , to o'rewhelm the earth . . but , since , these words were said to noe , who had already liv'd six hundred years ; if he had beheld the rainbow so many years , and afterwards experienc'd the floud ; he could not but have wondred it should import such a signification : we must say , therefore , that , without doubt , the rainbow was never us'd to be seen before the floud ; nor is it hard to render a reason on 't , out of what has been said . . for , since naturalists tell us , a rainbow is made out of a double or triple reflection or refraction of light in every drop of a light show'ry cloud ; whence proceeds this variety of colours : and light , so weak and scattered , or , the foresaid colours , cannot reach our eyes at such a distance , unlesse the aire be very clear and pure : and , through the humidity of the earth joyn'd with heat , a thick aire inveloped the earth all that time : 't was absolutely impossible a rainbow should be seen . . besides , it seems , that , for all the later years , a great masse of clouds must needs have so cover'd the face of the heavens , that the sun was rather felt then seen ; as we find 't is , for whole weeks , sometimes , together , in winter in those northern countries which , yet , are not excessively cold . no wonder , therefore , the rainbow had not shew'd it self before the floud . . next , 't is to be observ'd how god contracted the age of men , and with what he requited it . now , 't is evident , that the earth , by means of the deluge , became far colder and dryer : that 't was colder , after such a masse of waters , so long , not only covering and compressing it , but penetrating into its very bowells , any one will believe . . but , that water should dry , will perhaps hardlyer rellish : but , if we consider , that sodden things are rendred dry , through the extraction of their naturall moisture , when they are too much boil'd : if we reflect that trees are thrown by timber-men into water , least their native moisture should exuberate into rottennesse and worms ; and after a convenient time they are taken out again dryer then at first : if we observe that distillers , to extract the moisture of herbs , besprinkle the plants they are about with water or some other proportionate liquour : if lastly , we remember that gold-smiths , to separate the silver , mixt , in a little quantity , with other metalls , mix more silver withall : 't will be evident , that , when the earth redounded with well-digested moisture , there was no better way of drying it , then , by adding another moisture , to render that was in it more separable , and presse out both together ; as nature it self operates in rottennesse . . supposing , therefore , the earth became both colder and dryer , the plants and animals must of necessity have drawn a more malignant juyce & food out of it . for , since vegetation consists in heat & moisture ; death , and old age must be in their opposites , and out of them , be deriv'd to living creatures : wherefore , since , after the deluge , men sometimes liv'd & years , the long life of the patriarchs before the floud , mention'd in the scriptures , is not incredible . hence 't is that animals were now assign'd to man for food : and , 't is not said , that he shall rule over them , as at the beginning ; but the terrour of him shall be upon the other animals : for , at first , they serv'd him as instruments ; but now they were to become fierce and wild , whence man would contrive to kill them , and they , consequently , like perverse servants , fly and be affraid of him , as their chastizer . . and , these indeed god gave to man ; but another thing far greater . for , because the earth was become dryer , the aire too round about man was made purer and thinner ; and , both by his food and by the aire , his body was rendred , as , not so vast and durable , so , more subtile-spirited and more apt to be subjected to his soul , and fitter for the operations proper to it . . men , therefore , grew sharper witted and more addicted to sciences and arts ; and , by consequence , computing all things , the world became better and perfecter : since , there would , necessarily , be many more men , by reason of the littlenesse of their bodies , and such frequent changes , through the shortnesse of their lives ; and yet , nay much the rather , more forward and riper for the eternall life of the future world . chap. xix . of the second propagation of mankind into severall countries : out of the same holy history . . it remains , for describing perfectly the beginning of the world , to declare how the benediction , given to noe and his sons , to encrease and fill the earth , began to be fulfill'd . the divinely-deliver'd history , therefore , saies , that the first off-spring of noe agreed perfectly together , and were very unwilling to separate : which is collected out of those words , that , in the originall text , say the earth was one lip and the same words : for , that a lip signifies the words of men , is found , by the sense , every where ; as , when they are call'd deceitfull lips , our lips are from our selves , and in a thousand other places ; but , where 't is taken for a language , i know not . . but , because the sense of the following terms must be different , and the same words ; this phrase will signifie that they desired and sought how to remain united , as 't is said more manifestly below . whence , 't is no light suspicion , that this mind in them proceeded from the instigation of some one that affected a tyranny over mankind ; which some historians , also , witnesse . . proceeding , therefore , in this thought , they sat down in the fields about babylon ; and there , either mutually impell'd by one another , or else by some one , as i said , they deliberated from the opportunity & commodiousnesse of bricks and pitch , to build themselves a city and a tower : for two reasons , to get themselves a name , and to prevent their being dispersed over the earth ; for , so the hebrew reading has it , least perhaps , or rather , least at any time , which ours renders before . . they imagin'd , therefore , that , fixing their abode , by reason of the commodiousnesse of the vast city , and for the famousnesse of the tower , which would have no fellow , all men would willingly stay about those places . of the tower 't is said in the hebrew , whose head in heaven , that is , where the birds fly , or even the clouds ; intimating , that they design'd to continue on this edifice even to the clouds , which naturalists say , sometimes , are not rais'd more then paces above the earth : which height is not so vast and extravagant that it might not fall into the thoughts of men , and even be perfected , too ; according to what god said , that they would not desist , till they should have accomplisht them in deed . . but god turn'd their own very counsells upon their own heads : for the fond pains , and perhaps , ( which some histories insinuate ) because the tower , when it had been brought to a very great height , was thrown down by the winds and lightnings , ( as it uses to happen to extreme high fabricks ) made them weary of the work and its authour , so that they would no longer obey him , nor even agree together : but severall companies , as they could agree among themselves , departed into severall countries ; the authour of the work , with those that consented to him , remaining still in babylon . . and , this explication is clear , nor in any sort violent to the letter ; and according to the nature of things : whereas , that which the most follow contains so vast a miracle ( and whereof we have no other example , unlesse , perhaps , in the effusion of the holy ghost ) ; that it may seem violent to extract it out of words , in their ordinary sense , signifying another thing . for , to be of one lip , & lips to be confounded or tongues , agrees with common sense to signifie , the one , consent , the other , dissention : but to transferre these to multitude of languages is lesse naturall : which yet , if otherwise there were a sufficient authority , to shew the effect done , is no waies to be rejected ; but , if the whole story draws its originall from this only text , it will have no bottome nor solidity . . but hence , perhaps , some may ground their belief , that 't is not easie to imagine whence languages should have been divided amongst mankind , and have grown into so many kinds . to which we reply , that , whoever shall but observe what is usuall in his own city or countrey , will easily discern how so great a variety of dialects has grown into the world . for , 't is evident , the perfection of a language consists among the better-bred ; and the rude people corrupt the lesse usuall words , those that speak fast cut them short , the countrey folks likewise make a speciall pronunciation of their own . adde to these , that divers cities and provinces have form'd dialects of their own ; which yet , ther 's no doubt , are contain'd all under one idiome . . consider , then , the minglings of distinct languages ; a country sometimes being subdu'd by a nation of a different idiome ; sometimes , by the frequent travels of single persons , the words of one idiome being deriv'd to another . . lastly , let 's reflect on the originall root of diversity : which consists in this , that , words are compos'd of vowels and consonants ; and the differences of vowels rise from a wider or a more form'd and regular opening both of the mouth and throat ; but , that of consonants proceeds from an interception of the breath going out through the divers organs of the teeth , lips , tongue ; from its allision to them and the palate of the mouth ; with some help of the nostrills and the shutting up of the throat . . now , 't is evident , these members and instruments of voice are compos'd of the elements ; and consequently , from their temperament , are more dispos'd to one motion then to another ; and , which follows , that , from the site of the regions where men live , they are more inclin'd to some vowels or consonants then to others : whence it comes to passe , that , without any farther pains , vowels and consonants are chang'd by little and little , and ther 's such a diversity made , that they can no longer understand one another . . and , that the difference of idioms grew after this manner , from the very beginning ; it may be hence conjectur'd , because the chaldaick , syriack , arabick tongues discover a manifest derivation from and affinity with the hebrew . and , that the aegyptian , too , of old sprung from it , seems hence conjecturable , that in all the peregrinations of the patriarchs , or even the commerces of the kings with aegypt , ther 's no where any mention that they did not understand one another : moreover , the aegyptian names commemorated in scripture , as moyses , pharao , nechao , putiphar &c. are hebrew names , too . farther , 't is plain , that the very name babel is hebrew ; which , yet , remain'd to the city from which the family of heber is believ'd to have departed , and to have gone and resided far enough off ; if indeed melchisedech was of that family . . to conclude , it seems naturall to the originall tongue to be very short , viz. of monosyllables only , as much as concerns the primitive words : and the primitive words , of necessity , are of a determinate number , since , we scarce find more then seven first-consonants ; for the rest are varied either in a greater or lesse aspiration , or by the composition of more together ; whence , 't would be no hard thing to find the number of all the primitive words : wherefore , 't is clear , there cannot be many originall idioms , whose primitive words should be monosyllables . . some will object , the hebrew is an originall , and yet not all its primitive words are monosyllables : v. gr . adam , eva , shamaim , ( which name god impos'd upon heaven ) abel , &c. and finally , babel it self . . 't is answer'd , adam , abel , and eva are monosyllables ; for , in adam , and abel , the article is joyn'd to the name : for , since god impos'd the name upon adam , 't is impossible he should have call'd him adam from the name of the earth : for , since adama signifies primarily a speciall nature of earth , which is red , and the name is transferr'd thence to the whole earth ; moreover , that sort of earth took the name of its colour , and the colours name is from the primitive dam which signifies bloud ; 't is not credible that god gave such a derivative name to man. adam , therefore , is , as it were , ha-dam , that is , the like , viz. to god. in like manner the name of abel is bel , that is , confusion ; as also babel signifies not confusion , but in confusion . the name of heaven is a derivative from the primitive mai , which is a monosyllable . but , the dissyllables which constitute the substance of that language as 't is amongst us , are compounded , though they seem to us primitives . thus , therefore , the second time , was the world , by division , replenisht with men : god turning our evils and vices into good to us ; and his providence so punishing our ills , and changing our goods into better , according to that of the apostle , we know that , to those that love god , all things cooperate for good , to those who , according to his purpose , are called saints . notes, typically marginal, from the original text notes for div a -e aristotles orall instructions to alexander . notes for div a -e el. . pr. . euclid . el. . pr. . el. . pr. . less . . numb . . less . . n. . less . . n. . notes for div a -e lesson . b. . les . . n. . les . . n. . n. . . notes for div a -e b. . les . . n. . b. . less . . n. . les . . n. . b. . les . . n. . b. . les . . n. . les . . n. . . notes for div a -e b. . les . . n. . b. . les . . n. . n. , , &c. b. . les . . n. . les . , , &c. les . . n. . less . . n. . b. . les . . n. . les . . les . . n. , . b. . les . . n. , . b. . les . . n. . les . . n. , . notes for div a -e chap. . n. . ch. . n. . chap. . b. . les . . a defence of the doctrine touching the spring and weight of the air propos'd by mr. r. boyle in his new physico-mechanical experiments, against the objections of franciscus linus ; wherewith the objector's funicular hypothesis is also examin'd, by the author of those experiments. boyle, robert, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing b estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) a defence of the doctrine touching the spring and weight of the air propos'd by mr. r. boyle in his new physico-mechanical experiments, against the objections of franciscus linus ; wherewith the objector's funicular hypothesis is also examin'd, by the author of those experiments. boyle, robert, - . sharrock, robert, - . [ ], p., [ ] leaf of plates : ill. printed by f.g. for thomas robinson ..., london : . this work contains the first formulation of boyle's law. edited by robert sharrock. errata: p. . reproduction of original in british library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng line, francis, - . air -- early works to . air-pump -- early works to . physics -- experiments -- early works to . - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - derek lee sampled and proofread - derek lee text and markup reviewed and edited - pfs batch review (qc) and xml conversion a defence of the doctrine touching the spring and weight of the air , propos'd by mr. r. boyle in his new physico-mechanical experiments ; against the objections of franciscvs linvs . wherewith the objector's funicular hypothesis is also examin'd . by the author of those experiments . london : printed by j. g. for thomas robinson bookseller in oxon , . the publisher to the reader . friendly reader , you may possibly in this volume have expected the appendix which the author heretofore promised , and has intended shall contain some additional experiments to those which were formerly publish'd , and are here now reprinted in this second edition . these following answers to franciscus linus and mr. hobbes are presented in compensation of the delay , and for your forbearance of that appendix , which ere long you may expect in kind . for the author having hinted the promise seems thereby to acknowledge the debt , and to be content to continue the obligation to see it performed . and these ought the rather to be his excuse , because the writing these answers , and publishing the sceptical chymist , and some other discourses , have been the principal hindrances to that piece ; which is really so near a readiness , that part of it has lyen at the press these six moneths : but yet it being not all perfected , the stationer was loth to delay any longer the publication of these , for which he has been so frequently call'd upon . and they ( though a latine edition is intended ) appear now the rather in english , that they may accompany the second edition of the original experiments , which were printed first in that language in octavo ; and that instead of the promised appendix they may complete the bulk of the quarto volume . as for that part of this piece that concerns mr. hobbes , it might have been larger : but the information that the author had that the learned dr. wallis was writing against some passages in mr. hobbes his dialogues ( as well that concerning the air as the rest ) was the occasion why his h. would make no animadversion on some passages therein , and thought it not fit to enlarge upon others . and for the errata of the press i hope they will not be many : however the author as to these is to be excused , who never ( in regard to his eyes and impediments on other occasions ) gives himself the trouble of corrections and revises ; neither could the publisher much attend the press , it being printed in a distant place from his usual abode . if , as i wish , you shall find this jealousie of mine to have been causless , you will have reason to give the piece that is so kindly offered , and leads you such rare and untrodden paths in the best way of natural philosophy , the fairer entertainment and acceptance . farewell . ro. sh. the avthor's preface and declaration . they that know how indispos'd i naturally am to contentiousness , will , i presume , wonder to see me publickly engaged in two controversies at once . but that i am still as averse as ever from entering into disputes that may handsomly be declin'd , the way wherein i have managed the following controversies will , i hope , evince . and the inducements i now have to appear in publick are such , that it would be hard for me to resist the being prevail'd on by them . for , in the first place , i was ( by name , as it were ) challenged by a person , who undertook to disprove not one or two of my conjectures , but as much of the whole body of my treatise as concern'd the spring of the air , which most of my explications suppose . and this being done by a learned man , who writes very confidently of the goodness of his hypothesis and arguments , and his book being soon after follow'd by another written by mr. hobbs , a man of name in the world ; there seem'd to be some danger that so early an opposition might oppress the doctrine i had propos'd , before it was well understood and duly ponder'd . wherefore i fear'd i might be wanting to the truth and my self , if i should at such a time be altogether silent ; especially since i might probably divert many who would otherwise be forward to appear against us , by letting them see how defensible our doctrine is even against such adversaries as hose i have reply'd to . and this course i the rather chose , that in case i should henceforward comply with those who would have me forbear to write any further of these controversies , it might not be presently inferr'd from my silence , that a good cause cannot enable a pen no better then mine to defend it . but i scarce doubt but that intelligent readers , especially those that are imbued with the principles of the corpuscularian philosophy , will be much more apt to think that i had reason to write the following discourses , then to think that i had any to make them so prolix : and especially ingenious men , that are accustomed to admit nothing that either is not intelligible , or is precarious , will think divers of the objections i reply to needed no answers , or at least no solemn ones . but to these i have four things to represent . and first , that which not a little swells the bulk of the following treatises , is the inserting those passages of my adversaries that i examine in their own words : which being a practice that i expect from any that shall think fit to animadvert upon any opinion or argument of mine ; i thought it but equitable to do what i desir'd to have done to me , though oftentimes i could not do it in a little room . next , i was the more willing to prosecute some of franciscus linus his objections , because the fear of being reduc'd to grant a vacuum has so prevail'd with many eminent persons bred up in the received philosophy of the schools , that though they disagree both with him and among themselves about the particular manner of solving the phaenomena of the torricellian experiment ; yet they agree in ascribing them to some extremely-rarefi'd substance that fills up the space deserted by the quicksilver . so that this opinion , as to the main , being approved by many eminent schoalrs , especially of that most learned order of the jesuites , ( to whom perhaps its congruity to some articles of their religion chiefly recommends it ) i was willing to pay them that respect , as not to dissent from persons , divers of whom for their eminence in mathematicks and other learning i much esteem , without shewing that i do it not but upon considerations that i think weighty . thirdly , though the examiners hypothesis have but few , and not very considerable , arguments to countenance it ; yet his objections against our doctrine ( the reply to which takes up the first part of the following treatise ) are such , as though they may be solidly answered by any that throughly understands our hypothesis , yet they may chance puzzle such readers as do not , and these possiblywill prove more then a few . and , lastly , because that sometimes when the argument objected did not perhaps deserve to be much insisted on , the argument treated of deserv'd to be considered ; i thought it not amiss to make use now and then of some such opportunities to illustrate the matter it self under consideration : which i the rather did for these two reasons ; first , because i find that , except by some able mathematicians and very few other contemplative men , the doctrine of the spring of the air , at least as i have proposed it , is not yet sufficiently apprehended , ( and therefore needs to be inclucated . ) insomuch that through a great part of some late discourses of men otherwise eminently learned , ( written against other elaterists , not me ) there seems to run so great and clear a mistake , perhaps for want of skill in the hydrostaticks , that i can scarce impute it to any thing , but to their not throughly understanding the hypothesis they would confute . and , next , because i was willing to lay down in my answer to the objections i examin'd , the grounds of answering such other arguments as may be built upon the same or the like principles . and perhaps i may truly enough say , that in the following treatise i have already in effect answered several discourses , written some before and some since mine , by learned men , about the torricellian and other new experiments relating to a vacuum , though i forbore to mention the names or words of the authors , because i found not that my writings or experiments were as yet known to them . to these things i may adde , that i thought the discourses of linus the fitter to be insisted on , because he seems to have more diligently then some others , ( who yet venture to dispute against it ) enquired into our doctrine . and i shall not scruple to say thus much of an adversary , ( and one to whom i gave no provocation to be so ) that though i dare not speak in general of those that have written either about the weight of the air , or else for or against a vacuum , because ( as i acknowledge in the first chapter following ) i cannot yet procure the books of divers learned men , especially of those great personages , robervall , balianus and casatus ; yet among the writers i have hitherto met with , who have recourse to the aristotelean rarefaction and condensation in the controversies under debate , scarce any seems to have contrived his hypothesis better then our linus . not that i think his principle is either true , or ( at least to such as i ) intelligible ; but that the funiculus he assumes being allow'd him , he may , for a reason to be touch'd a little below , make out , though not all the phaenomena of my experiments , yet many more of them then most other plenists , that deny the spring of the air , can deduce from their hypotheses if granted . and in regard that , whereas we ascribe to the air a motion of restitution outwards , he attributes to it the like motion inwards , it cannot but happen that , though the principles cannot both be true , yet many of the phaenomena may be explicable by which of them soever is granted : because of this , i say , it is not so easie as many ingenious readers may be apt to think , to draw pertinent objections from experience against the adversary i have to deal with . which irepresent , lest , as some may think i have employ'd more arguments then i needed , so others should think i have omitted many ; as indeed i have omitted some , that i might pertinently have employ'd . but there is another sort of persons besides those i mention'd at the beginning of this preface , to whom i must addresse the remaining part of it ; namely , to those who seem troubled , that i suffer my self to be diverted either by linus or mr. hobbs from perfecting those experimental treatises that are lying by me , almost promis'd by the learned publisher of the latine edition of my essays ; and from prosecuting those wayes of enquiry into the nature of things , wherein they are pleas'd to think i may be more serviceable to reall learning and the lovers of it . and i confess that these mens reasons and perswasions have so far prevailed with me , that after what i have done in the two following treatises , to vindicate my writings from the objections made against them by two learned men of very differing hypotheses , and thereby to shew in some measure that i am not altogether unacquainted with the way of defending oppos'd truths , i have laid aside the thoughts of writing any more distinct or entire polemicall treatises about the subjects already disputed of . and to this i am invited by several other reasons ( besides what i have newly intimated . ) for first , as i elsewhere declare , it was not my chief design to establish theories and principles , but to devise experiments , and to enrich the history of nature with observations faithfully made and deliver'd ; that by these , and the like contributions made by others , men may in time be furnish'd with a sufficient stock of experiments to ground hypotheses and theorys on . and though in my physico-mechanicall epistle and my specimens i have ventur'd some conjectures also at the causes of the phaenomena i relate , lest the discourse should appear to inquisitive readers too jejune ; yet ( as i formerly said ) i propos'd my thoughts but as conjectures design'd ( though not only , yet chiefly ) to excite the curiosity of the ingenious , and afford some hints and assistance to the disquisitions of the speculative . and accordingly i have not forborn to mention divers things , which judicious readers may easily perceive i foresaw that many , would think unfavourable to the opinions i inclin'd to . so that for me to leave experimental for controversial studies , were a course unsuitable to the principal scope of my writings . next , though i have adventur'd to improve the doctrine of the spring and weight of the air by some supplements where i found it deficient , and to recommend it by some new illustrations and arguments deduc'd from my experiments : yet the hypotheses themselves ( for the main ) being the opinions also of far learneder men then i , it might be thought injurious both to them and to our common cause , if i should needlesly go about to hinder them from the honour of vindicating the truths we agree in ; especially , some of them being excellent mathematicians , and others eminent naturalists , whose concern to maintain the hypotheses against objections , if any shall arise , is equal to mine , and whose leisure and abilities far exceed those of a person who both is sickly , and hath other employments enough , and who ( if he were far better skil'd in geometry then he pretends to be ) hath such a weakness in his eyes , as makes him both unwilling and unfit to engage in any study where the conversing with mathematical schemes is necessary . thirdly , nor do i see much cause to doubt that the things i have deliver'd will notwithstanding my silence be left undefended : the forwardness i have already observ'd in divers virtuosi to vindicate those writings , which they are pleas'd to say have convinc'd them , and to save me the labour of penning the following treatises , scarce permitting me such an apprehension . especially since there are some things that will much facilitate their task , if not keep men from putting them upon it . for though mr. hobbs and linus have examin'd my writings upon principles wherein they differ as much from each other as from me ; yet neither have they seen cause to deny any thing that i deliver as experiment , nor have their objections been considerable , whether as to number or to weight , against the applications i have made of my principles to solve the phaenomena . so that usually without objecting any incongruity to my particular explications , they are fain to fall upon the hypotheses themselves : in whose defence i think i may with the more reason expect to be seconded , because not only i have endeavour'd , as i formerly noted , to lay the grounds of answering such objections as i foresaw might arise ; but i have also , to prevent or ease their labour , written the two first parts of my defence against linus , without being oblig'd to do so for the vindicating of my explications , which are particularly maintain'd in the third part. i know not whether i may venture to adde on this occasion , that those who have taken notice of the usefulness of experiments to true philosophy , and have observ'd that neverthelesse the difficulty , trouble , and charge of making them is such , that even in this learned age of ours there are very few bacon's or mersennus's to be met with , and those who have either made themselves , or at least seen others make experiments , even such as those i have publish'd , with the care i am wont to think my self oblig'd to employ on such occasions ; will perhaps not only believe that they cost me far more time and pains then they that have not made or seen such tryals are apt to imagine , but will possibly think it enough for a person that is not by profession a scholar , to make them carefully , and set them down faithfully , and will allow him to let others vindicate the truths he may have the good fortune to discover , especially , when there are so many fitter for it then he , who have ( as well as his adversaries ) more leisure to write disputations then opportunity to prosecute experiments ; the latter of which to be perform'd as it ought to be , doth in many cases , besides some dexterity scarce to be gain'd but by practice , require sometimes more diligence , and oftentimes too more cost , then most are willing , or then many are able , to bestow upon them . to be short , though if any thing very worthy to be taken notice of by me be suggested against any of my chief opinions or explications , i may either take an occasion to say somewhat to it elsewhere , or at least have an opportunity to consider it in a review , wherein i may alter , mend , supply , vindicate or retract divers passages of my other writings : yet i would not have it expected that i should exchange a book with every one that is at leisure to write one against a vacuum , or about the air. which declaration i make , not that i think it will or ought to hinder any man from making use of his liberty to expresse a dissent , if he sees cause ; but for these two reasons . the one , that my silence might not injure either the truth or my self , by tempting men to think , that whatever i do not answer , i cannot ; but might give unbiass'd and judicious readers a caution to allow as little of advantage to the writings of my adversaries upon the account of their being unanswer'd by me , as if i were no longer in the world. and the other , that i may not hinder those who would reply to such adversaries , by leaveing them an apprehension that either i may prevent them , or they me . to conclude , i see no cause to despair , that whether or no my writings be protected , the truths they hold forth will in time in spite of opposition establish themselves in the minds of men , as the circulation of the bloud , and other formerly much contested truths have already done . my humour has naturally made me too careful not to offend those i dissent from , to make it necessary for any man to be my adversary upon the account of personal injuries or provocations . and as for any whom either judgment or envy may invite to contend , that the things i have communicated to the world deserved not so much applause as they have had the luck to be entertain'd with ; that shall make no quarrel betwixt us : for perhaps i am my self as much of that mind as he ; and however i shall not scruple to prosess my self one of those who is more desirous to spend his time usefully , then to have the glory of leaving nothing that was ever written against him unanswer'd ; and who is more sollicitous to pursue the wayes of discovering truth , then to have it thought that he never was so much subject to humane frailties as to miss it . a defence of mr. r. boyle's explications of his physico-mechanical experiments , against franciscus linus . the i. part. wherein the adversaries objections against the elaterists are examined . chap. i. a newly published treatise , de corporum inseparabilitate , being brought to my hands , i find several chapters of it employ'd to oppose the explications i ventur'd to give of some of my new experiments touching the spring of the air. wherefore though i am very little delighted to be engag'd in controversies , and though i be not at present without employments enough ( of a private , and of a publick nature ) to make it unseasonable for me , to be by a work of this sort diverted from them ; yet for the reasons specified in the preface , i hold it not amiss to examine briefly what is objected against the thing i have delivered : and the rather , partly , because the learned author , whoever he be ( for 't is the title-page of his book that first acquainted me with the name of franciscus linus ) having forborne provoking language in his objections , allowes me in answering them to comply with my inclinations & custom of exercising civility , even where i most dissent in point of judgement . besides , the author himselfe has somewhat facilitated my reply to him , by directing me in the ninth page to some books and passages that i had not , when i publisht my epistle , either seen or taken notice of . as indeed there are besides some of these several other discourses that treat of the torrecellian experiments , which though by the names of their authors i guess to be learnedly written , i have not to this day had opportunity to peruse , my stay in the remoter parts of ireland ( whither philosophical books were not , in that time of publick confusion , brought ) having kept me from hearing of divers of them , till they were all bought up . which i here mention , to excuse my self if i have not taken notice of some things or passages to be met with in these writings , which their learned authors or inquisitive readers might justly perhaps expect i should take some notice of , in case those writings had fallen into my hands . but to digress no further . 't is true indeed , and it somewhat troubles me that it is so , that i can scarce promise my self to make my adversary a proselyte , since he without scruple assumes those very things as principles , that to me seem almost as great inconveniences as i would desire to shew any opinion i dislike , to be liable unto . but since whatever operation the following discourse may have upon the person that occasion'd it , i hope it may bring some satisfaction to those philosophers who can as little as i understand the aristotelean rarefaction , and who will as well as i be backward to admit what they cannot understand ; it shall suffice me to defend the truths i have deliver'd , if i cannot be so happy as to convince my acute adversary of them ; and i shall not believe my labour lost , if this discourse can contribute to the establishment of some notions in philosophy that i think not inconsiderable , in the minds of those whose clear principles make me the most respect their judgements , and for whose sakes i principally write . now though i be not in strictness oblig'd to defend any more then such of my own explications as the examiner has thought fit to question , and those particulars which i have added by way of improvement to the two hypotheses of the spring and weight of the air : yet that i may the more effectually prosecute what i lately intimated i aim at in this writing , and may as well illustrate my doctrine as defend it , i shall divide the ensuing treatise into three parts ; whereof the first is design'd to answer my adversaries objections against our principles ; the second shall examine the funicular hypothesis he would substitute in their stead ; and the third shall contain particular replyes to what he alledges against some of my particular explications . chap. ii. although our author confesses in his second chapter , that the air has a spring as well as a weight , yet he resolutely denies that spring to be near great enough to perform those things which his adversaries ( whom for brevities sake we will venture to call elaterists ) ascribe to it . and his whole fourth chapter , as the title declares , is imploy'd to prove that the spring of the air is unable in a close place to keep the mercury suspended in the torrecellian experiment . the proof of this assertion he sayes is easie : but alledges two or three arguments for it , which i think will be more easily answer'd then his assertion evinc'd . in the first he sayes that those experiments concerning the adhesion of ones finger , &c. which he had mentioned in the foregoing chapter , eodem modo se habent in loco clauso ac in aperto . but the answering of this we shall suspend till anon ; partly , because it may then be more conveniently examin'd , and partly , because our author seems not to build much upon it , his chief argument being that which he proposes in these words , cum tota vis hujus elaterii pendeat à refutato jam aëris aequipondio cum digitis ½ argenti vivi , ita ut nec plus , nec minus faciat hoc elaterium in loco occluso , quam fit per illud aequipondium in loco aperto ; manifestum est , cum jam ostensum sit fictitium planè esse hujusmodi aequipondium , fictitium quoque esse tale elaterium . wherefore since all the validity of his objection against the spring of the air depends upon his former chapter , wherein he thinks he has disprov'd the weight of the air ; it will behove us to look back into the former chapter , and examine the four arguments which he there proposes . but i must crave leave to vary from his method , and consider the third in the first place , because the removal of that objection will facilitate and shorten the answer to the rest . his third argument therefore is thus set down . nam si tubus viginti tantum digitorum ( quo usi sumus in primo argumento ) non totus impleatur argento , ut prius , sed spatium aliquod inter digitum superiorem & argentum relinquatur in quo fit solus aër ; videbimus substracto inferiore digito superiorem non solum deorsum trahi ; ut prius , sed etiam argentum jam descendere , idque notabiliter , quantum nimirum extendi potest exigua illa aëris particula à tali pondere descendente . unde si loco illius aëris ponatur aqua , aliusve liquor qui non tam facilè extenditur , descensus nullus erit . hinc , inquam , contra hanc sententiam formatur argumentum : nam si externus ille aër neque at velhos viginti digitos argenti à lapsu sustentare , uti jam vidimus , quomodo quaeso sustentabit ½ ? certè haec nullatenus reconciliari possunt . but to this argument , which he thinks so irreconcilable with his adversaries hypothesis , he has himself furnisht them with an answer in these words , dices forte ideo argentum in hoc casu descendere , quia deorsum truditur ab aëre illo sese per suum elaterium dilatante . which answer i think sufficient for the objection , notwithstanding the two exceptions he takes at it . for first , whereas he sayes , that sic deberet digitus potius à tubo repelli , quam eidem affigi , cum non minus sursum quam deorsum fiat hujusmodi dilatatio : he considers not , that though the endeavour of the included air to expand it selfe be at first every way alike , yet the expansion it selfe in our case must necessarily be made downward , and not upward ; because the finger that stops the tube being expos'd on the upper parts and the sides to the external air , has the whole weight and pressure of the atmosphere upon it ; and consequently cannot be thrust away but by a force capable to surmount that pressure : whereas on the lower side of the included air there is the weight of the whole mercurial cylinder to assist the spring of the air , to surmount the weight of the atmosphere that gravitates upon the restagnant mercury . so that the air included and endeavouring to expand it selfe , finding no assistance to expand it self upward , and a considerable one to expand it selfe downward , it is very natural that it should expand it selfe that way whence it finds less resistance . as accordingly it will happen , till the spring of the air be so far debilitated by its expansion , that its pressure , together with the weight of the mercury that remains suspended , will but counter-balance , not overcome , the pressure of the outward air upon the restagnant mercury . and this explication may be confirm'd by this trial that i have purposely made , namely , that if in stead of quicksilver you employ water , and leave as before in the tube an inch of air , and then inverting it , open it under water , you will perceive the included inch of air not to dilate it selfe any thing near ( for i need not here define the proportion ) halfe so far as it did when the tube was almost fill'd with mercury ; because the weight of so short a cylinder of water does but equal that of between an inch and an inch and an halfe only of quicksilver , and consequently the inward air is far less assisted to dilate it self and surmount the pressure of the outward air by the cylinder of water then by that of mercury . and as for what our author sayes , that if instead of air , water or some other liquor be left at the top of the tube , the quick-silver will not descend : the elaterists can readily solve that phaenomenon , by saying that water has either no spring at all , or but an exceeding weak one ; and so scarce presses but by its weight , which in so short a cylinder is inconsiderable . now the same solution we have given of our examiners objection , gives us also an account why the finger is so strongly fastned to the upper part of the orifice of the tube it stops ; for the included air being so far dilated that an inch , for example , left at first in the upper part of the tube , reaches twice or thrice as far as it did before the descent of the quick-silver , its spring must be proportionably weakned . and consequently that part of the finger that is within the tube will have much less pressure against it from the dilated air within , then the upper part of the same finger will have from the unrarefi'd air without . by which means the pulp of the finger will be thrust in ( which our author is pleas'd to call suckt in ) as we shall ere long have occasion to declare in our answer to his second argument . and having said thus much to our authors first exception against the solution he foresaw we would give of his third argument ; we have not much to say at present to his second . for whereas he sayes , concipi non posse quomodo aër ille sic se dilatet , argentumque deorsum trudat , nisi occupando majorem locum : quod tamen hi autores quam maxime refugiunt , asserentes rarefactionem non aliter fieri , quam per corpuscula aut vacuitates : i wish he had more clearly express'd himself , since as his words are couch'd i cannot easily guess what he means , and much less easily discern how they make an argument against his adversaries . for , sure he thinks them not so absurd , as to imagine that the air can dilate it self , and thrust down the mercury , without in some sense taking up more room then it did before : for the very word dilatation , and the effect they ascribe to the included air , clearly imply as much ; so that i see not why he should say that they are so averse from granting the air to take up more place then before , especially since he takes notice in the former chapter , that we compare the expansion of the air to that of compress'd wooll ; and since he here also annexes that we explicate rarefaction either by corpuscles or vacuities . but this later clause makes me suspect his meaning to be , that the elaterists do not admit that the same air may adequately fil more of place at one time then at another ; which i believe to be as true as that the self-same lock of compress'd wooll has no more hairs in it , nor does adequately fill more place with them , when it is permitted to expand it self , then whilest it remain'd compress'd . but against this way of rarefaction our author here has not any objection , unless it be intimated in these words , concipi non potest : which if it be , i shall need only to mind him in this place , that whereas many of the chiefest philosophers , both of ancient and our own times , have profest they thought not the aristotelean way of rarefaction conceivable ; and he acknowledges ( as we shall see anon ) that it is not clear ; what the ablest of his party ( the modern plenists ) are wont to object against the way of rarefaction he dislikes , is , that it is not true , not that it is not intelligible . chap. iii. our authors second objection ( for so i reckon it ) is thus propos'd by him . si sumatur tubus utrinque apertus , sed longior , put a digitorum . argentoque impleatur , eique digitus supernè applicetur ut prius , videbimus subtracto inferiore digito , argentum quidem descendere usque ad consuetam suam stationem ; digitum autem superiorem fortiter intra tubum trahi , eique firmissime , ut prius , adhaerere . ex quo rursum evidenter concluditur , argentum , in sua statione constitutum , non ibidem sustentari ab externo aëre , sed à funiculo quodam interno suspendi , cujus superior éxtremitas , digito affixa , eum sic intra tubum trahit , eique affigit . but this argument being much of the same nature with that drawn from his third experiment , the answer made to that and to his first may be easily apply'd , and will be sufficient for this also ; especially because in our present case there is less pressure against the pulp of the finger in the inside of the tube then in the third experiment ( where some air is included , though much expanded and weakned ; ) the pressure of the atmosphere being in the present case kept off from it by the subjacent mercury , whereas there is nothing of that pressure abated against the other parts of the finger that keep it off from the deserted cavity of the tube , save only that from the pulp that is contiguous to the tube , there may be somewhat of that pressure taken off by the weight of the glass it self . but as for that part of the finger which immediately covers the hole , whether or no there be any spring in its own fibres , or other constituent substances , which finding no resistance in the place deserted by the quick silver , may contribute to its swelling ( for that we will not now examine ) he that has duly consider'd the account already given of this intrusion of the pulp into the glass , will find no need of our authors internal funiculus , which to some seems more difficult to conceive , then any of the phaenomena in controversie is to be explain'd without it . chap. iv. by what we have already said against our examiners third argument , we may be assisted to answer his first , though he propose it as a very clear demonstration ; and though it be indeed the principal thing in his book . sumatur ( sayes he ) tubus brevior digit is ½ puta digitorum . non tamen clausus altero extremo , ( ut hactenus ) sed utrinque apertus : eic tubus , immerso ejus orificio argento restagnanti , suppes●oque digito , n●effluat argentum tubo infundendum , impleatur argento vivo : aliusque deinde digitus orificio quoque applicetur , illudque bene claudat . quo facto , si subtrahatur inferior digitus , sentietur superior vehementer trahi , ac sugi intra tubum , tamque pertinaciter ei ( vel argento potius , ut postea ) adhaerere , ut ipsum tubum cum toto argento incluso facilè elevet teneatque in vase pendulum . ex quo sane experimento clarissimè refellitur haec sententia : cum enim , juxta eam , argentum in tubo hujusmodi . tantum digitorum , sursum trudatur à praeponderante ante aëre externo : nunquam profecto per eam explicabitur , quomodo digitus ille sic trahatur deorsum , tuboque tam vehementer adhareat ; non enim à trudente sursum potest sic deorsum trahi . thus far our authors objection , in answer whereunto i have divers things to represent , to shew , that a good account may be given of this experiment in the hypothesis of the elaterists , which is sufficient to manifest how far the argument is from being so unanswerable as the proposer of it would perswade his reader . i deny then that the finger is drawn downward , or made by suction to adhere to the tube ; but i explicate that which he calls the suction of the finger , as i lately did in answer to his third argument , as we shall more particularly see anon . he sayes indeed , that the air which thrust up the quicksilver cannot so strongly draw down the finger . as if the air were not a fluid body , but a single and entire pillar of some solid matter . but to shorten our reply to his objections , the best way perhaps will be briefly to explicate the phaenomenon thus : when the tube is fill'd with quicksilver , the finger that stops the upper orifice is almost equally press'd above and at the sides by the contiguous air ; but when the lower finger is remov'd , then the cylinder of mercury , which before gravitated upon the finger , comes to gravitate upon the restagnant mercury , and by its intervention to press against the outward air : so that against those parts of the finger that are contiguous to the air there is all the wonted pressure of the outward air ; whereas against that pulp that is contiguous to the mercury there is not so much pressure as against the other parts of the finger by two thirds . i say by two thirds , or thereabout , because the mercurial cylinder in this experiment is suppos'd to be twenty inches high ; and if it were but a little more then thirty inches high , ( which is a third more ) then the weight of the quicksilver would take off not two thirds onely , but the whole pressure of the outward air , from the above-mentioned pulp of the finger . for in that case the quicksilver would quite desert it , and settle beneath it . wherefore since it has appeared by our answer to the examiners third argument , that the pressure of the outward air is taken off from the body that remains in the upper part of the tube , according to the weight of the liquor suspended in the tube ; and since in our hypothesis the pressure of the outward air is able to keep thirty inches of quicksilver , or two or three and thirty foot of water , suspended in a tube ; it need be no great wonder , if a pressure of the ambient air , equal to the weight of a cylinder of water of near twenty two foot long , should be able to thrust in the pulp of the finger at the upper orifice of the tube , and make it stick closely enough to the lip of it . i know the examiner affirms , that no thrusting or pressure from without can ever effect such an adhesion of the finger to the tube . but this should be as well prov'd as said . but , first , though i am willing to think the examiner would not knowingly relate any thing he is not perswaded of ; yet as far as i and another person very well vers'd in these experiments have purposely tryed , i could not find the adhesion of the finger to the tube to be near so strong as our author hath related . secondly , if you carefully endeavour by pressure and otherwise to thrust the pulp of your finger into the orifice of the tube , you may through the glass perceive it to be manifestly tumid in the cavity of the pipe. and if by pressing your finger against the orifice of the tube , you should not make the pulp adhere quite so strongly to the tube , nor swell quite so much within it , as may happen in some mercurial experiments ; it is to be consider'd , that the air being a fluid as well as a heavy body , it does not ( as grosser weights would ) press only against the upper part of the finger , but pressing as much of the finger as is expos'd to it almost every where , and almost uniformly , as well as strongly , it does by its lateral pressure on every side thrust in the pulp of the finger into the hole where there is not any resistance at all , or at least near so much pressure against the pulp as that of the ambient air against the parts of the finger contiguous to it . by this it may appear that we need not borrow the objection our author offers to lend us ; namely , that in the experiment under consideration the quicksilver is press'd downward by the spring of some air lurking betwixt it and the finger . ( though i am prone to think that unless the experiment be made with a great deal of care , such a thing may easily happen , and contribute to the stronger adhesion of the finger to the tube . ) this i say may appear notwithstanding what our author objects , that the air expanding it self wil thrust away the finger upwards , since the contrary of that pretence we have lately manifested in the answer to his third argument . and as for what he adds to confirm his argumentation in these words , quod vel inde confirmatur , quia cum praponderans ille aër succedat ( uti asseritur ) loco sublati inferioris digiti , id est , eodem modo nunc sustentet argentum quo ante ab applicato digito inferiore sustentabatur ; manifestum est , non debere , juxta hanc sententiam , magis deorsum trahi digitum superiorem post sublatā inferiorem quam ante . cum it aque contrarium planè doceat experientia , satis liquet sententiam illam esse falsam . we must consider that the tube being suppos'd perfectly full of mercury , the finger that stops the lower orifice is wont to be kept strongly press'd against it , lest any of that ponderous liquor should get out between the tube and the finger . so that although both the lower finger do indeed keep up the mercury in the tube , and the pressure of the outward air would do so too ; yet there is this difference , that the pressure of the atmosphere depending upon its weight , cannot be intended and weakned as we please , as can that of the undermost finger . and therefore whereas the atmospherical cylinder will not keep up a cylinder of quicksilver of above thirty inches high , those that make the torricellian experiment do often , upon one occasion or other , keep up with the , finger a mercurial cylinder of perhaps forty or fifty inches or far more : so that whereas in our case , before the removal of the undermost finger , the pulp of the uppermost must have about the same pressure against it where it is contiguous to the mercury , as there is against the other part of the same finger ; after the removal of the undermost finger , there is as much of the atmospherical pressure , if i may so speak , taken off from the newly-mention'd pulp as counter-balances a cylinder of quicksilver of twenty inches long . chap. v. the examiners fourth and last experiment is thus propos'd . quarto denique ( sayes he ) impugnatur : quia ex eo sequeretur , argentum vivum per similem tubum è vasculo exsugi posse eâdem prorsus facilitate quâ ex eodem exsugeretur aqua : quod tamen experientiae repugnat , quâ docemur aquam in ●s sugentis facillime attrahi ; quo tamen argentum vivum ne toto quidem adhibito conatu perduci queat , imo vix ad tubi medietatem . sequelam autem sic ostendo : quia cum in hac sententia nihil aliud agendum sit quam hoc , ut per tubum sic ascendat subjectus liquor , sive aqua fuerit , sive argentum , nisi ut sugendo sursum trahatur aër tubo inclus s , quo sic attracto ascendit illico subjectus liquor , protrusus nimirum ab externo aëre jam praeponderante ( uti docet pecquetius in dissertatione anatomica pag. . ) manifestum est , eadem planè facilitate exsugendum sic argentum vivum qua exsugitur aqua : quod quum experientiae tam aperte repugnat , necesse est sententiam ex qua sequitur falsam esse . this experiment i remember i made some years ago , accordingly 't is alledg'd in the fourth essay of the treatise ( i was then writing ) to prove against the vulgar opinion , that liquors do not to prevent a vacuum spontaneously ascend , which i presume will be so far allow'd of by our author , who would have liquors suppos'd to be rais'd by suction violently drawn up by the contraction of his funiculus . but to examine this experiment , as it concerns the present controversie , we may recal to mind that we formerly shew'd in the answer to our authors third argument , that when the mercurial cylinder that leans upon the restagnant mercury has at the other end of it air , kept from any entercourse with the atmosphere , that included air has so much of the pressure of the external air taken off from it as counterpoises the mercurial cylinder . and the finger that is expos'd to the whole pressure of the ambient air in some of its parts , and in others but to the much fainter pressure of the included air , endures an unusual pressure from the preponderating power of the atmosphere . we may consider also that there is against the thorax and those muscles of the abdomen that are subservient to respiration the pressure of the whole ambient air. which pressure , notwithstanding the muscles design'd for the use of respiration , are able without any considerable resistance to dilate the thorax at pleasure ; because , as fast as they open the chest , and by dilating it weaken the spring of that air which is then within the body , the external air by flowing in , for want of finding the usual resistance there , keeps that within the thorax in an aequilibrium of force with that without . these things premised , 't is not difficult in our hypothesis to give an answer to the examiners experiment . for we say when a cylinder of mercury is rais'd in the tube to any considerable height , the pressure of the air in the thorax is lessen'd by the whole weight of that mercurial cylinder , and consequently the respiratory muscles are thereby disabled to dilate the chest as freely as they were wont , by reason of the prevalency of the undiminish'd pressure of the external air against the weakned pressure of the internal : but if in stead of mercury , you substitute water , so short a cylinder of that comparatively light liquor takes off so little of the pressure of the included air , that it comes into the lungs with almost its usual strength , and consequently with almost as much force as the outward air presses with against the thorax . and on this occasion there occurrs to my thoughts a noble experiment of the most ingenious monsieur paschal , which clearly shews , that if we could free the upper part of such a tube as we are now considering from the pressure of all internal air , it would follow , as the examiner sayes it should , that the quicksilver would by the pressure of the outward air be impell'd up into the tube as well as water , till it had attain'd a height great enough to make its weight not inferiour but equal to that of the atmosphere . the experiment it self being so pertinent and considerable , we shall annex it in the same words wherein it is related by his country-man and acquaintance , the learned and candid gassendus . neque hoc verò solum , sed insuper vitreo diabete clysteréve ea qua par fuerit longitudine confecto , & post embolum ad orificium usque compulsum , immisso ad normam in subjectum hydrargyrum deprehendit , ubi embolum sensim deinde educitur , consequi hydrargyrum ascendereque ad eandem usque duorum pedum & digitorum trium cum semisse altitudinem . to which he immediately subjoynes a circumstance very considerable to the present controversie in the following clause . ac ubi deinceps , adhibita licet non majore vi , embolum altius educitur , consistere hydrargyrum , neque amplius consequi , ac fieri interim inane quod spatium intercipitur ab ipso ad embolum usque . thus far he . so that as to the examiners experiment , we may well explicate it in our hypothesis , by saying , that agreeably to it it happens , that in a more forcible respiration the mercurial cylinder is raised higher then in a more languid ; because , in the former case , the chest being more dilated , the included air is also more expanded ; whereby its debilitated spring cannot as before enable the mercurial cylinder to counterpoise altogether the pressure of the ambient air. and that the reason why the quicksilver is not by respiration rais'd as high as it is kept suspended in the torricellian experiment , is not , that the pressure of the outward air is unable to raise it so high , but because , as we have already declar'd , the free dilatation of the thorax is opposed by the pressure of the ambient air ; which pressure being against so great a superficies , and being but imperfectly resisted by the debilitated pressure of the air within the thorax , will be easily imagined to be very considerable by him who considers that in our engine , the pressure of the external air against the sucker of less then three inches diameter was , as we relate in the . experiment , able to thrust up a weight of above a hundred pound . and here we may observe upon the by in confirmation of our former doctrine , that when we strongly suck up quicksilver in a glass tube , though the elevation of the quicksilver be according to our author performed likewise by his funiculus contracting it selfe every way , and though there be a communication betwixt the internal surface of the lungs , and the cavity of the tube ; yet we feel not in our lungs any endeavour of the shrinking funiculus to tear off that membrane they are lin'd with . and thus we have examin'd our authors four arguments , to prove that in the torricellian experiment the quicksilver cannot be kept suspended by the counterpoise of the external air : against which opinion he tells us indeed , that other arguments might be alledg'd , but as it is not probable that if he had thought them better then those he has elected to insist on , he would have omitted them ; so 't is not unlikely that answers might be as well found for them as for the others ; especially since that which he singles out for a specimen is , that from his adversaries hypothesis it would follow , that the quicksilver would descend much more ( i suppose 't is a mistake of the press , for much less ) in cold weather then in hot , because the air is then thicker and heavier , and therefore ought to impel up the quicksilver higher . for besides that we shall in its due place question the validity of our authors consequence ; it will be here sufficient to reply , that the observation on which he grounds it does not constantly hold , as his objection supposes : which may appear by that part of our . experiment whence the matter of fact is desum'd , as we shall have occasion-to take further notice of when we shall come to the defence of that experiment . so that what has been hitherto discours'd on both sides being duly consider'd , the reader is left to judge what ground the examiner had for the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 wherewith he is pleas'd to conclude his third chapter , maneat igitur tot argumentis comprobatum , quorum quodlibet se solo suf ficit , argentum ( facto experimento in loco aperto ) per externi aëris gravitatem à lapsu minimè sustentari . chap. vi. his fourth chapter , wherein the title promises that he will prove , argentum in loco occluso non sustentari à lapsu per ipsum aëris elaterium , is very short , and does not require that we should dwell long upon it . for the proof he brings of his assertion being this , cum tota vis hujus elaterii pendeat à refutato jam aëris aequipondio cum digitis ½ argenti vivi , ita ut nec plus net minus faciat hoe elaterium in loco occluso quam fit-per illud aequipondium in loco aperto ; manifestum est , cum jam oftensum sit fictitium planè esse hujusmodi aequipondium , fictitium quoque esse tale elaterium : this being no new argument , but an inference from those he had set down in the former chapter , by our answers to them it is become needless for us to make any distinct reply to this . we shal rather desire the reader to take notice , that whereas our author sayes that according to his adversaries , ncc plus nec minus faciat hoc elaterium in loco occluso quam fit per illud aequipondium in loco aperto ; whatever others may have written , we for our part allow of this opinion but in some cases ; for in others we have perform'd much more by the spring of the air , which we can within certain limits increase at pleasure , then can be perform'd by the bare weight , which for ought we know remains alwayes somewhat near the same . and of this advantage that the spring of the air may have in point of force above the weight of it , we have formerly given an instance in our . experiment , ( where , by compressing the air in the receiver , we impell'd the mercurial cylinder higher then the station at which the counterpoise of the air is wont to sustain it ) and shall hereafter have occasion to give yet more considerable proofs . to the lately recited words our examiner subjoyns these ; adde , cum allata jam capite praecedente experimenta de adhaesione digiti , &c. eodem modo se habent in loco clauso ac in aperto , necessarium esse facta ex eis argumenta contra aquipondium , eadem quoque contra elaterium vim habere . but though he propose this as a new argument , yet since 't is built but upon the adhesion of the finger ( of which we have already given an account in our hypothesis ) i see not how it requires any new and particular answer . and whereas he sayes , that the experiments he had mentioned concerning the adhesion of ones finger , &c. eodem modo se habent in loco clauso ac in aperto ; i could wish he had added what way he took to make the tryals . for he gives no intimation that he did them any other wayes then in ordinary rooms . and in such there scarce ever wants a communication betwixt the inward and outward air , either at the chimney , or window , or door not exactly shut , or at some hole or crevice or other , by means of which the weight of the atmosphere has its operation within the room . to his second argument our author adds not a third , unless we take that for an argument which he immediately annexes to his last recited words : et profectò ( sayes he ) si secum expenderent hi authores , quanta sit difficultas explicandi hujusmodi aëris elaterium , nisi idem aër se solo occupet majorem locum ( ut paulo ante ) credo eos sententiam facilè mutaturos . but this being said gratis , does not exact an answer ; and he must make it more intelligible then any man that i know of has yet done , how the same air can adequately fill more space at one time then at another , before he perswade me to change my opinion about the spring of the air : especially since he himself allowes that the air has a spring , whereby it is able , when it has been violently compress'd , to recover its due extension ; the manner whereof if he will intelligibly explicate , his adversaries will have no great difficulty to make out the spring of the air. but whether his hypothesis , or ours , be the more intelligible , will be more properly considered in the second part of our discourse , to which we will therefore now proceed . the ii. part. wherein the adversaries funicular hypothesis is examin'd . chap. i. what is alledged to prove the funiculus is consider'd ; and some difficulties are propos'd against the hypothesis . the hypothesis that the examiner would , as a better , substitute in the place of ours , is , if i mistake it not , briefly this ; that the things we ascribe to the weight or spring of the air are really perform'd by neither , but by a certain funiculus , or extremely thin substance , provided in such cases by nature , ne detur vacuum , which being exceedingly rarefied by a forcible distension , does perpetually and strongly endeavour to contract it self into dimensions more agreeable to the nature of the distended body ; and consequently does violently attract all the bodies whereunto it is contiguous , if they be not too heavy to be remov'd by it . but this hypothesis of our authors does to me , i confess , appear liable to such exceptions , that though i dislik'd that of his adversaries , yet i should not imbrace his , but rather wait till time and further speculations or tryals should suggest some other theory , fitter to be acquiesc'd in then this ; which seems to be partly precarious , partly unintelligible , and partly insufficient , and besides needless : though it will not be so convenient to prove each of these apart , because divers of my objections tend to prove the doctrine , against which they are alledged , obnoxious to more then one of the imputed imperfections . first , then , the arguments by which our author endeavours to evince his funiculus , are incompetent for that end . the arguments which he proposes in his sixth chapter ( where he undertakes to make good his assertion ) i there find to be three . the first he sets down in these words , constat hoc primò ex jam dictis capite praecedente : nequit enim argentum descendens sic digitum deorsum trahere , tuboque affigere , nisi à tali funiculo suspendatur , eumque suo pondere vehementer extendat , ut per se patet . but to this proof answer has been made already in the former part of this discourse : onely whereas the author seems to refer us to the foregoing chapter , we will look back to it , and take notice of what i find there against the vacuists . for though i neither am bound , nor intend , in this discourse to declare my selfe for , or against , a vacuum ; yet since i am now writing against the funicular hypothesis . it will much conduce to shew that it is not firmly grounded , if i examine what he here alledges against the assertors of a vacuum . in the next place therefore i consider that , according to the examiner , there can be no vacuum ; and that he makes to be the main reason why nature in the torricellian and our experiments does act after so extraordinary a manner , as is requisite to the production of his funiculus . for in the . page , having in his adversaries name demanded what need there is at the descent of the quicksilver , that before it falls a superficies should be separated from it , and extended ; respondeo ( sayes he ) ideo hoc fieri , ne detur vacuum ; cum nihil aliud ibi adsit quod loco argenti descendentis possit succedere . to which he immediately subjoyns , ( with what cogency i will not now examine : ) atque hinc plane confirmatur commune . illud per tot jam elapsa secula usurpalum in scholis axi●●●a viz. naturam à vacuo , abhorrere . and though he seem to make his funiculus the immediate cause of the phaenomena occurring in the torricellian and our experiments : yet that , if you pursue the inquiry a little higher ; he resolves them into natures abhorrency of a vacuum , himself plainly informs us in the next page ; namlicet ( sayes he ) immediata ratiocur aqua v. g. ex hydria hortulana superne clausa ( quo exemplo . utuntun ) non descendat , non sit metus vacui , sed ea quam modo diximus , nempe quod non detur sufficiens pondus ad solvendum illum nexum quo adhaer eat aqua clausae hydriae summitati ; ad eam tamen rationem tandem necessario veniendumest . but , though as well our author 's fumiculus , as the other scarce conceivable hypotheses that learned men have devised , to account for the suspension of the quicksilver otherwise then by the resistance of the external air , seem to have been excogitated onely to shun the necessity of admitting a vacuum : yet i see not how our examiner cogently proves , either that there can be none in rerum naturâ , or that defacto there is none produc'd in these experiments . for in his fifth chapter ( where he professedly undertakes that task ) he has but these two incompetent arguments . the first is drawn from the attraction , as he supposes , of the finger into the deserted cavity of the tube in the torricellian experiment : quaequidem ( sayes he ) tam vehemens tractio & adhaesio , cum non nisi à reali aliquo corpore inter digitum & argentum constitutum queat provenire , manifestum est spatium illud vacuum non esse , sed verâ aliquâ substantiâ repletum . but to this argument having already given an answer , let us ( without staying to urge , that the vacuists will perhaps object , that they see not a necessity , though they should admit of traction in the case , that the internal substance must therefore perfectly replenish the deserted cavity ; without pressing this , i say , let us ) consider his other , which he draws from the diaphaneity of the deserted part of the tube , which space ( he sayes ) were it empty , would appear like a little black pillar , eo quod nullaespecies visuales neque ab eo neque per illud possunt ad oculum perventre . but ( not to engage our selves in optical speculations and controversies ) if we grant him some what more then perhaps he can prove ; yet as the experiment will not demonstrate that there is nothing of body in any part of the space deserted by the mercury , so neither will the argument conclude ( as the proposer of it does twice in this chapter ) that space verâ aliquâ substantiâ repleri . for according to the hypothesis of the epicureans and other atomists , who make light to be a corporeal effluvium from lucid bodies , and to consist of atoms so minute , as freely to get in at the narrow pores of glass , there will be no cause to deny interspers'd vacuities in the upper part of the tube . for the corpuscles of light that permeate that space may be so numerous , as to leave no sensible part of it un-inlightned ; and yet may have so many little empty intervals betwixt them , that , if all that is corporeal in the space we speak of were united into one lump , it would not perhaps adequately fill the one half ( not to say the tenth , or even the hundredth part ) of the whole space : according to what we have noted in the . experiment , that a room may appear full of the smoke of a perfume , though if all the corpuscles that compose that smoke were re-united , they would again make up but a small pastil . to which purpose i remember i have taken camphire , of which a little will fill a room with its odour , and having in well-clos'd distillatory glasses caught the sumes driven over by hear , i thereby reduc'd them to re conjoyn into true camphire , whose bulk is very inconsiderable in comparison of the space it fills as to sense , when the odorous corpuscles are scattered through the free air. to which i might adde , that the torricellian experiment being made in a dark night , or in a room perfectly darken'd , if it succeed ( as there is little cause to suspect it will not ) it may well be doubted whether our authors argument will there take place . for if he endeavour to prove that the place in question was full in the dark , because upon the letting in of the day , or the bringing in of a candle , the light appears within it ; the vacuists may reply according to their hypothesis , that that light is a new one , flowing from the lucid body that darts its corporeal beams quite through the glass and space we dispute about , which for want of such corpuscles were not just before visible . and supposing light not to be made by a trajection of atoms through diaphanous bodies , but a propagation of the impulse of lucid bodies through them ; yet it will not thence necessarily follow , that the deserted part of the tube must be full : as in our . experiment ( though many of those gross aerial particles that appear'd necessary to convey a languid sound were drawn out of our receiver at the first and second exsuction ; yet there remain'd so many of the like corpuscles , that those that were wanting were not miss'd by the sense , though afterwards , when a far greater number was drawn out , they were ) so there may be matter enough remaining to transmit the impulse of light ; though betwixt the particles of that matter there should be store of vacuities intercepted . whereas our author pretends to prove , not onely that there is no coacervate vacuity in the space so often mentioned , but absolutely that there is none . for 't is in this last sense , as well as the other , that the schools and our author , who defends their opinion , deny a vacuum . but notwithstanding what we have now discours'd , as in our . experiment we declin'd determining whether there be a vacuum or no ; so now what we have said to the examiners argument , has not been to declare our whole sense of the controversie , but onely to shew , that though his hypothesis supposes there is no vacuum , yet his arguments do not sufficiently prove it : which may help to shew his doctrine to be precarious ; for otherwise the cartesians , though plenists , may plausibly enough ( whether truly or no i now dispute not ) decline the necessity of admitting a vacuum in the deserted space of the tube , by supposing it fill'd with their second and first element , whose particles they imagine to be minute enough freely to pass in and out through the pores of glass . but then they must allow the pressure of the outward air to be the cause of the suspension of the quicksilver : for though the materia coelestis may readily fill the spaces the mercury deserts ; yet that within the tube cannot binder so ponderous a liquor from subsiding as low as the restagnant mercury ; since all the parts of the tube , as well the lowermost as the uppermost , being pervious to that subtile matter , it may with like facility succeed in whatever part of the tube shall be for saken by the quicksilver . the examiners second argument in the same place is , that since the mercurial cylinder is not sustain'd by the outward air , it must necessarily be , that it be kept suspended by his internal string . but since for the proof of this he is content to refer us to the third chapter ; our having already examin'd that , allows us to proceed to his third argument , which is , that the mercurial cylinder , resting in its wonted station , does not gravitate : as may appear by applying the finger to the immers'd or lower orifice of the tube . whence he infers , that it must of necessity be suspended from within the tube . and indeed if you dexterously apply your finger to the open end of the tube , when you have almost , but not quite , lifted it out of the restagnant mercury , ( which circumstance must not be neglected , though our author have omitted it ) that so you may shut up no more quicksilver then the mercurial cylinder is wont to consist of , you will find the experiment to succeed well enough : ( which makes me somewhat wonder to find it affirm'd , that the learned maignan denies it ) not but that you will feel upon your finger a gravitation or pressure of the glass-tube , and the contained mercury , as of one body ; but that you will not feel any sensible pressure of the mercury apart , as if it endeavoured to thrust away your finger from the tube . but the reason of this is not hard to give in our hypothesis ; for according to that , the mercurial cylinder and the air counterpoising one another , the finger sustains not any sensibly-differing pressure from the ambient air that presses against the nail and sides of it , and from the included quicksilver that presses against the pulp . but if the mercurial cylinder should exceed the usual length , then the finger would feel some pressure from that surplusage of quicksilver , which the air does not assist the finger to sustain . so that this pleasant phaenomenon may be as well solv'd in our hypothesis , as in the examiners : in which if we had time to clear an objection , which we fore-see might be made , but might be answer'd too ; we would demand why , when the mercury included in the tube is but of a due altitude , it should run out upon the removal of the finger that stops it beneath , in case it be sustain'd onely by the internal funiculus , and do , according to his doctrine , when the funiculus sustains it , emulate a solid body , if the pressure of the external air has not ( as our author teaches it not to have ) any thing to do in this matter . and if some inquisitive person shall here object , that certainly the finger must feel much pain by being squeez'd betwixt two such pressures , as that of a pillar of thirty inches of quick-silver on the one side , and an equivalent pressure from the atmospherical pillar on the other , it may readily be represented , that in fluid bodies ( such as are those concern'd in our difficulty ) a solid body has no such sense of pressure from the ambient bodies as ( unless experience had otherwise instructed us ) we should perhaps imagine . for , not to mention that having inquired of a famous diver , whether he found himself sensibly compressed by the water at the bottom of the sea ; he agreed with the generality of divers in the negative : i am inform'd that the learned maignan did purposely try , that his hand being thrust three or four palmes deep into quicksilver , his fingers were not sensible , either of any weight from the incumbent , or of any pressure from the ambient , quicksilver . the reason of which ( whether that inquisitive man have given it or no ) is not necessary in our present controversie to be lookt after . to these three arguments the examiner addes not a fourth , unless he design to present it us in this concluding passage : huc etiam faciunt insignes librationes quibus argentum subito descendens agitatur : idem enim hic fit quod in aliis pendulis & ab alto demissis fieri solet . but of this phaenomenon also 't is easie to give an account in our hypothesis by two several wayes ; whereof the first ( which is proper chiefly when the experiment is made in a close place , as our receiver ) is , that the quicksilver by its sudden descent acquires an impetus superadded to the pressure it has upon the score of its wonted gravity ; whereby it for a while falls below its station , and thereby compresses the air that leans upon the restagnant mercury . which air by its own spring again forcibly dilating it self to recover its former extension , and ( as is usual in springs ) hastily flying open , expands it self beyond it , and thereby impells up the quicksilver somewhat above its wonted station , in its fall from whence it again acquires somewhat ( though not so much as before ) of impetus or power , to force the corpuscles of the air to a sub-ingression ; and this reciprocation of pressure betwixt the quicksilver and the outward air decreasing by degrees , does at length wholly cease , when the mercury has lost that superadded pressure , which it acquired by its falling from parts of the tube higher then its due station . but this first way of explicating these vibrations is not necessary in the free air : for if we consider the ambient air onely as a weight , and remember what we have newly said of the impetus acquir'd by descent ; this phaenomenon may be easily enough explain'd , by taking notice of what happens in a balance , when one of the equiponderant scales chancing to be depress'd , they do not till after many vibrations settle in aequilibrio . and on this occasion i shall adde this experiment : i took a glass pipe , whose two legs ( very unequal in length ) were parallel enough , and both perpendicular to that part of the pipe that connected them , ( such a syphon is describ'd in our . experiment , to find the proportion of the gravity of mercury and water ) into this quicksilver was pour'd till 't was some inches high , and equally high in both legs : then the pipe being inclin'd till the most part of the quicksilver was fallen into one of the legs , i stopt the orifice of the other leg with my finger , and erecting again the pipe , though the quicksilver were forc'd to ascend a little in that stopt leg ; yet by reason my finger kept the air from getting away , the quicksilver was kept lower by a good deal in that stopt leg then in the other ; but if by suddenly removing my finger i gave passage to the included and somewhat comprest air , the preponderant quicksilver in the other leg would with the mercury in this unstopt leg , make divers undulations before that liquor did in both legs come to rest in an aequilibrium . of which the reason may be easily deduc'd from what has been newly deliver'd ; and yet in this case there is no pretence to be made of a funiculus of violently distended air to effect the vibrations of the mercury . chap. ii. divers other difficulties are objected against the funicular hypothesis . thirdly , but though our examiner have not sufficiently proved his hypothesis , yet perhaps it may be in its own nature so like to be true , as to deserve to be imbrac'd as such . wherefore we will now take notice of some of those many things that to our apprehension render it very improbable . and first , whereas our author acknowledges that quicksilver , water , wine , and other liquors , will , as well one as another , descend in tubes exactly sealed at the top , in case the cylinder of liquor exceed the weight of a mercurial cylinder of ½ . inches ; and will subside no longer then till it is come to equiponderate a cylinder of quicksilver of that height ; whereas , i say , the examiner is by the ingenious monsieur paschall's , and other experiments , induc'd to admit this ; it cannot but seem strange that , whatever the liquor be , there should be just the same weight or strength to extend them into a funiculus : though water , for instance , and quicksilver be near fourteen times as heavy one as the other , and be otherwise of very distant natures ; and though divers other liquors , as oyle and water , be likewise of textures very differing . and this may somewhat the more be wondred at , because our author ( in his animadversions upon our . experiment ) is pleased to make so great a difference betwixt the disposition of bodies of various consistences , as fluid and firm , to be extenuated into a funiculus , that he will not allow any humane force to be able to produce one , by the divulsion of two flat marbles , in case the contact of their surfaces were so exquisite as quite to exclude all air ; though in the same place his ratiocination plainly enough teaches ( which experience however does ) that adhering marbles , though with extraordinary difficulty , may be forcibly sever'd , and according to him the superficial parts may be distended into a funiculus , that prevents a vacuum . but now the hypothesis of his adversaries is not at all incumbred with this difficulty . for the weight of the outward air being that which keeps liquors suspended in tubes sealed at the top ; it matters not of what nature or texture the suspended liquor is , provided its weight be the same with that of a mercurial cylinder equiponderant to the aerial one : as if there be a pound of lead in one scale , it will not destroy the aequilibrium , whether what be put in the other be gold , or quicksilver , or wooll , or feathers , provided its weight be just a pound . in the next place we may take notice , that the account our examiner gives us of his funiculus in the tenth chapter , ( where he takes upon him to explicate it ) is much more strange then satisfactory , and not made out by any such parallel operations of nature , as his adversaries will not ( and may not well do it ) dispute the truth of . whereas the weight and spring of the air may be inferr'd from such unquestion'd experiments as are not concern'd in our present controversie . for the gravity of the air may be manifested by a pair of scales , & the spring of it discloses it self so clearly in wind-guns and other instruments , that our adversary ( as we have already had occasion to inculcate ) does not deny it . but to consider his explication of his funiculus , he would have us note two things : first , argentum dum replet totum tubum , non mere tangere ejus summitatem ( ut primo aspectu videtur ) sed eidem quoque firmiter adhaerere . patet hoc ( subjoyns he ) experimento illo in primo argumento capit is tertii de tubo utrinque aperto . but what is to be answer'd to this proof may be easily gathered from what we have replyed to that argument . and to what our author addes to prove , that the adhesion of the finger is to the subjacent mercury , not to the tube ; namely , that licet illud tubi orificium oleo , aliâve materiâ adhaesionem impediente , inungatur , non minus tamen firmiter adhaerebit digitus quàm priùs ; an answer may be drawn from the same place ; nor perhaps will his reasoning much satisfie those who consider that bodies by trusion may easily enough be made stick together , as much as in our case the tube and finger do , notwithstanding one of them is anoynted with oyle , and that this adhesion of the finger to the tube is to be met with in cases where the surface of the included quicksilver is not contiguous to the finger , but many inches below . as for what he addes concerning the reason why water , and quicksilver ascend by suction , we have already taught what is to be answered to it , by ascribing that ascension to the pressure of the external air : without any need of having recourse to a funiculus ; or imagining with him in this place , that because nothing besides the water or quicksilver can in such cases succeed , the air , ( which yet is not easie to be prov'd in reference to a thin aethereal substance ) therefore , partes ipsius aëris ( to use his expression ) sic tubo inclusae ( quae aliàs tam facile separantur ) nunc tam fortiter sibi invicem agglutinentur , ut validissimum ( uti videmus ) conficiunt catenam , qua non solum aqua , sed ponderosum illud argentum sic in altum trahatur . which way of wreathing a little rarefied air into so strong a rope , how probable it is , i will for a while leave the reader to judge , and advance to our author's second notandum , which he thus proposes : rarefactionem sive extensionem corporis ad occupandum majorem locum fieri non solo calore , sed etiam distensione seu vi divulsivâ : sicut è contra condensatio non solo frigore perficitur , sed etiam compressione , uti innumera passim docent exempla . and 't is true and obvious , that the condensation of bodies , taking that word in a large sense , may be made as well by compression as cold . but i wish he had more clearly exprest what he means in this place by that rarefaction , which he sayes is to be made by distension , or a vis divulsiva , whereof he tells us there are innumerable instances . for , as far as may be gathered from the three examples he subjoyns , 't is onely the air that is capable of being so extended as his hypothesis requires quicksilver and even stones must be . and i know not how it will be proved , that even air may be thus extended so far , as in the magdeburg experiment , to fill a place more then two thousand times as big as that it fill'd before . for that the same air in this and his two foregoing instances does adequately fill more space at one time then another , he proves but by the rushing in of water into the evacuated glass , and filling it within a little quite full , which , he sayes , is done by the distended air that contracting it self draws up the water with it . which explication how much less likely it is , then that the water is in such cases impell'd up by the pressure of the atmosphere , we shall anon ( when we come to discuss his way of rarefaction and condensation ) have occasion to examine . in the mean time let us consider with him the explication which , after having premis'd the two above recited observations , he gives us of his funiculus ; cum per primum notandum argentum ita adhaereat tubi vertici , & per secundum , rarefactio fiat per meram corporis distensionem , ita rem se habere , ut argentum descendens à vertice tubi affixam ei relinquat superficiem suam extimam sive supremam , eamque eousque suo pondere extendat extenuetque , donec facilius sit aliam superficiem similiter relinquere quam priorem illam ulterius extendere : secundam igitur relinquit , eamque eodem modo descendendo extendit , donec facilius sit tertiam adhuc separari quam illam secundam extendere ulterius : & sic deinceps , donec tandem vires amplius non habeat superficies sic separandi & extendendi ; nempe donec perveniat ad altitudinem digitorum duntaxat ½ , ubi quiescit , ut capite primo dictum est . thus far our examiners explication : by which 't is easie to discern , that he is fain to assigne his funiculus a way of being produc'd strange and unparallell'd enough . for , not to repeat our animadversions upon the first of the two notandum's , on which the explication is grounded , i must demand by what force , upon the bare separation of the quicksilver and the top of the tube , the new body he mentions comes to be produc'd ; or at least how it appears that the mercury leaves any such thing as he speaks of behind it . for the sense perceives no such matter at the top of the tube , nor is it necessary to explicate the phaenomena as we have formerly seen . it may also be marvell'd at , that the bare weight of the descending mercury should be able to extend a surface into a body . and besides , it seems precariously affirm'd , that there is such a successive leaving behind of one surface after another as is here imagin'd : nor does it at all appear how , though some of the quicksilver were turn'd into a thin subtile substance , yet that substance comes to be contriv'd into a funiculus of so strange a nature , that scarce any weight ( for ought appears by his doctrine ) can be able to break it ; that contrary to all other strings it may be str●●●●ed without being made more slender ; and that it has other very odde properties , some of which we shall anon have occasion to mention . as for what our author subjoynes in these words , eodem itaque fere modo separari videntur hae superficies ab argento descendente , & in tenuissimum quendam per descendens pondus extendi , quo per calorem in accensa candela separantur hujusmodi superficies à subjecta cera aut sevo , & in subtilissimam flammam extenuantur . ubi not atu dignum , quemadmodum flamma illa plusquam millies sine dubio majus spatium occupat , quàm antea occupaverat pars illa cerae ex qua conficitur ; ita prorsus & his existimandum funiculum illum plusquam millies majus spatium occupare quàm prius occupaverat illa argenti particula ex qua sit exortus : uti etiam sine dubio contingit , quando talis particula à subjecto igne in vaporem convertitur . though it be the onely example whereby he endeavours to illustrate the generation of his funiculus , yet ( i presume ) he scarce expects we should think it an apposite one . for , besides that there here intervenes a conspicuous and powerful agent , namely , an actual fire to sever and agitate the parts of the candle ; and besides that there is a manifest wasting of the wax or tallow turn'd into flame ; besides these things , i say , we must not admit , that the fuel when turn'd into a flame does really fill ( i say not , with our author ) more then a thousand times , but so much as twice more of genuine space then the wax 't was made of . for it may be said that the flame is little or nothing else then an aggregate of those corpuscles which before lay upon the upper superficies of the candle , and by the violent heat were divided into minuter particles , vehemently agitated and brought from lying as it were upon a flat to beat off one another , and make up about the wiek such a figure as is usual in the flame of candles burning in the free air. nor will it necessarily follow , that the space which the flame seems to take up should contain neither air nor aether , nor any thing else , save the parts of that flame , because the eye cannot discern any other body there : for even the smoke ascending from the snuff of a newly-extinguish'd candle appears a dark pillar , which to the eye at some distance seems to consist of smoke ; whenas yet there are so many aerial and other invisible corpuscles mingled with it , as if all those parts of smoke that make a great show in the air were collected and contiguous , they would not perhaps amount to the bigness of a pins head : as may appear by the great quantity of steams that in chymical vessels are wont to go to the making up of one drop of spirit . and therefore it does not ill fall out for our turn , that the examiner , to inforce his former example , alledges the turning of a particle of quicksilver into vapour , by putting fire under it : for if such be the rarefaction of mercury , 't is not at all like to make such a funiculus as he talks of , since those mercurial fumes appear by divers experiments , to be mercury divided and thrown abroad into minute parts , whereby though the body obtain more of surface then it had before , yet it really fills no more of true and genuine space , since if all the particular little spaces fill'd by these scatter'd corpuscles were reduc'd into one , ( as the corpuscles themselves often are in chymical operations ) they would amount but to one total space , equal to that of the whole mercury before rarefaction . but these objections against this explication are not all that i have to say against our adversaries funiculus it self . for i farther demand how the funiculus comes by such hooks or graple-irons , or parts of the like shape , to take fast hold of all contiguous bodies , and even the smoothest , such as glass , and the calm surfaces of quicksilver , water , oyle , and other fluids : and how these slender and invisible hooks cannot onely in the tersest bodies find an innumerable company of ears or loops to take hold on , but hold so strongly that they are able not alone to lift up a tall cylinder of that very ponderous metall of quicksilver , but to draw inwards the sides of strong glasses so forcibly , as to break them all to pieces . and 't is also somewhat strange , that water and other fluid bodies ( whose parts are wont to be so easily separable ) should , when the funiculus once layes hold on the superficial corpuscles , presently emulate the nature of consistent bodies , and be drawn up like masses each of them of an intire piece ; though even in the exhausted receiver they appear by their undulation ( when they are stir'd by bubbles that pass freely through them ) and many other signs to continue fluid bodies . it seems also very difficult to conceive how this extenuated substance should acquire so strong a spring inward as the examiner all along his book ascribes to it . nor will it serve his turn to require of us in exchange an explication of the airs spring outward , since he acknowledges , as well as we , that it has such a spring . i know , that by calling this extenuated substance a funiculus , he seems plainly to intimate that it has its spring inward , upon the same account that lute-strings and ropes forcibly stretch'd have theirs . but there is no small disparity betwixt them : for whereas in strings there is requir'd either wreathing , or some peculiar and artificial texture of the component parts ; a rarefaction of air ( were it granted ) does not include or infer any such contrivance of parts as is requisite to make bodies elastical . and if the cartesian notion of the cause of springiness be admitted , then our extenuated substance having no pores to be pervaded by the materia subtilis ( to which besides our author also makes glass impervious ) will be destitute of springiness . and however , since lute-strings , ropes , &c. must , when they shrink inwards , either fill up or lessen their pores , and increase in thickness as they diminish in length ; our examiners funiculus must differ very much from them , since it has no pores to receive the shrinking parts , and contracts it self as to length , without increasing its thickness . nor can it well be pretended that this self-contraction is done ob fugam vacui , since though it should not be made , a vacuum would not ensue . and if it be said that it is made that the preternaturally stretch'd body might restore it self to its natural dimensions : i answer , that i am not very forward to allow acting for ends to bodies inanimate , and consequently devoid of knowledge ; and therefore should gladly see some unquestionable examples produc'd of operations of that nature . and however to me , who in physical enquiries of this nature look for efficient rather then final causes , 't is not easie to conceive how air by being expanded ( in which case its force ( like that of other rarify'd bodies ) seems principally to tend outwards , as we see in fired gun-powder , in aeolipiles , in warm'd weather-glasses , &c. ) should acquire so prodigious a force of moving contiguous bodies inwards . nor does it to me seem very probable , that , when for instance part of a polish'd marble is extended into a funiculus , that funiculus does so strongly aspire to turn into marble again . i might likewise wish our author had more clearly explicated , how it comes to pass ( which he all along takes for granted ) that the access of the outward air does so much and so suddenly relax the tension of his funiculus ; since that being ( according to him ) a real and poreless body , 't is not so obvious how the presence of another can so easily and to so strange a degree make it shrink . but i will rather observe , that 't is very unlikely that the space which our adversary would have replenish'd with his funicular substance , should be full of little highly-stretcht strings , that lay fast hold of the surfaces of all contiguous bodies , and alwayes violently endeavour to pull them inwards . for we have related in our . experiment , that a pendulum being set a moving in our exhausted receiver , did swing to and fro as freely , and with the string stretch'd as streight , as for ought we could perceive it would have done in the common air. nay , the balance of a watch did there move freely and nimbly to and fro ; which 't is hard to conceive those bodies could do , if they were to break through a medium consisting of innumerable exceedingly-stretch'd strings . on which occasion we might adde , that 't is somewhat strange that these strings , thus cut or broken by the passage of these bodies through them , could so readily have their parts re-united , and without any more ado be made intire again . and we might also take notice of this as another strange peculiarity in our authors funiculus , that in this case the two divided parts of each small string that is broken do not , like those of other broken strings , shrink and fly back from one another ; but ( as we just now said ) immediately redintegrate themselves : whereas , when in the torricellian experiment the tube and contain'd mercury is suddenly lifted up out of the restagnant quicksilver into the air , the funiculus does so strangely contract it self , that it quite vanishes ; insomuch that the ascending mercury may rise to the very top of the tube . these , i say , and divers other difficulties might on this occasion be insisted on ; but that , supposing our selves to have mentioned enough of them for once , we think it now more seasonable to proceed to the remaining part of our discourse . chap. iii. the aristotelean rarefaction ( proposed by the adversary ) examin'd . but this is not all that renders the examiners hypothesis improbable : for , besides those already mentioned particulars , upon whose score it is very difficult to be understood ; it necessarily supposes such a rarefaction and condensation , as is , i confess , to me , as well as to many other considering persons , unintelligible . for the better discernment of the force of this objection we must briefly premise , that a body is commonly said to be rarefi'd or dilated , ( for i take the word in a larger sense then , i know , many others do , for a reason that will quickly appear ) when it acquires greater dimensions then the same body had before ; and to be condens'd , when it is reduc'd into less dimensions , that is , into a lesser space then it contain'd before : ( as when a dry spunge being first dipp'd in water swells to a far greater bulk , and then being strongly squeez'd and held compressed , is not onely reduced into less room then it had before it was squeezed , but into less then it had even before it was wetted . ) and i must further premise , that rarefaction ( as also condensation ) being amongst the most obvious phaenomena of nature , there are three ( and for ought we know but three ) wayes of explicating it : for , either we must say with the atomists and vacuists , that the corpuscles whereof the rarefied body consists do so depart from each other , that no other substance comes in between them to fill up the deserted spaces that come to be left betwixt the incontiguous corpuscles ; or else we must say with divers of the ancient philosophers , and many of the moderns , especially the cartesians , that these new intervals produced betwixt the particles of the rarefied body are but dilated pores , replenished , in like manner as those of the tumid spunge are by the imbibed water , by some subtile aethereal substance , that insinuates it self betwixt the disjoyned particles : or , lastly , we must imagine with aristotle and most of his followers , that the self-same body does not onely obtain a greater space in rarefaction , and a lesser in condensation , but adequately and exactly fill it , and so when rarefied acquires larger dimensions without either leaving any vacuities betwixt its component corpuscles , or admitting between them any new or extraneous substance whatsoever . now 't is to this last ( and , as some call it , rigorous ) way of rarefaction that our adversary has recourse in his hypothesis : though this , i confess , appear to me so difficult to be conceived , that i make a doubt whether any phaenomenon can be explained by it ; since to explain a thing is to deduce it from something or other in nature more known then it self . he that would meet with full discussions of this aristotelean rarefaction , may resort to the learned writings of gassendus , cartesius and maignan , who have accused it of divers great absurdities : but for my part , i shall at present content my self to make use to my purpose of two or three passages that i meet with ( though not together ) in our author himself . let us then suppose , that in the magdeburg experiment he so often ( though i think causlesly enough ) urges to prove his hypothesis ; let us ( i say ) for easier considerations sake suppose , that the undilated air , which ( as he tells us ) possessed about half an inch of space , consisted of a hundred corpuscles , or ( if that name be in this case disliked ) a hundred parts ; ( for it matters not what number we pitch upon ) and 't will not be denyed , but that as the whole parcel of air , or the aggregate of this hundred corpuscles , is adequate to the whole space it fills , so each of the hundred parts , that make it up , is likewise adequately commensurate to its peculiar space , which we here suppose to be a hundredth part of the whole space . this premised , our author having elsewhere this passage , corpore occupante locum verbi gratia duplo majorem , necesse est ut quaelibet ejus pars locum quoque duplo majorem occupet ; prompts us to subjoyn , that in the whole capacity of the globe ( which according to him was two thousand times as great as the room possessed by the unexpanded air ) there must likewise be two hundred thousand parts of space commensurate each of them to one of the fore-mentioned hundredth parts of air ; and consequently , when he affirms that that half inch of air possessed the whole cavity of the globe , if we will not admit ( as he does not ) either vacuities or some intervening subtile substance in the interval of the aeriall parts , he must give us leave to conclude , that each part of air does adequately fill two thousand parts of space . now that this should be resolutely taught to be not onely naturally possible , ( for we dispute not here of what the divine omnipotence can do ) but to be really and regularly done in this magdeburg experiment , will questionless appear very absurd to the cartesians and those other philosophers , who take extension to be but notionally different from body , and consequently impossible to be acquir'd or lost without the addition or detraction of matter ; and will , i doubt not , appear strange to those other readers , who consider how generally naturalists have looked upon extension as inseparable , and as immediately flowing from matter ; & upon bodies , as having necessary relation to a commensurate space . nor do i see , if one portion of air may so easily be brought exactly to fill up a space two thousand times as big as that which it did but fill before without the addition of any new substance ; i see not ( i say ) why the matter contained in every of these two thousand parts of space may not be further brought to fill two thousand more , and so onwards , since each of these newly-replen shed spaces is presumed to be exactly filled with body , and no space , nor consequently that which the unrarefied air replenished , can be more then adequately full . and since , according to our adversary , not onely fluid bodies , as air and quicksilver , but even solid and hard ones , as marble , are capable of such a distension as we speak of , why may not the world be made i know not how many thousand times bigger then it is , without either admitting any thing of vacuity betwixt its parts , or being increased with the addition of one atome of new matter ? which to me is so difficult to conceive , that i have sometimes doubted , whether in case it could be proved , that in the exhausted globe we speak of there were no vacuities within , nor any subtile matter permitted to enter from without , it were not more intelligible to suppose that god had created a new matter to joyn with the air in filling up the cavity , then that the self-same air should adequately fill two thousand spaces , whereof one was exactly commensurate to it even when it was uncompressed . for divers eminent naturalists , both ancient and modern , believing upon a physical account the souls of men to be created and infused , will admit it as intelligible that god does frequently create substances on certain emergent occasions . but i know that many of them will not likewise think it conceivable , that without his immediate interposition an accession of new , real dimensions should be had without either vacuities or accession of matter . and indeed when i considered these difficulties and others , that attend the rarefaction our examiner throughout his whole book supposes , and when i found that ever and anon he remits us to what he teaches concerning rarefaction ; i could not but with some greediness resort to the chapters he addressed me to . but when i had perused them , i found the difficulties remained such still , and that 't was very hard even for a witty man to make more of a subject then the nature of it does bear . which i say , that by professing my self unsatisfied with what he writes , i may not be thought to find fault with a man for not doing what perhaps is not to be done , and for not making such abstruse notions plain , as are scarcely ( if at all ) so much as intelligible . and indeed as he has handled this subject modestly enough , so in some places his expressions are to me somewhat dark ; which i mention , not to impute it as a crime in him , that he wrote in a diffident and doubtful strain of so difficult a matter , but to excuse my self if i have not alwayes guessed aright at his meaning . the things he alledges in favour of the rarefaction he would perswade are two : the one , that the phaenomena of rarefaction cannot be explicated either by vacuities or the subingression of an aethereal substance ; and the other , that there are two wayes of explicating the rigorous rarefaction he contends for . his objections against the epicurean and cartesian wayes of making out rarefaction are some of them more plausible then most of those that are wont to be urged against them ; yet not such as are not capable enough of answers . but whilest some of the passages appeared easie to be replyed to by the favourers of the hypothesis they oppose , before i had fully examined the rest , chancing to mention these chapters to an ingenious man , hereafter to be further mentioned in this treatise ; he told me he had so far considered them more then the rest of the book , that he had thought upon some hypotheses , whereby the phaenomena of rarefaction might be made out either according to the vacuists , or according to the cartesians , adding , that he had also examined the instance our adversary pretends to be afforded him of his rarefaction by what happens in the rota aristotelica . wherefore being sufficiently distressed by avocations of several sorts , and being willing to reserve the declaration of my own thoughts concerning the manner of rarefaction and condensation for another treatise , i shall refer the reader to the ingenious conjectures about this subject , which the writer of them intends to annex to the present discourse ; and onely adde in general , that whereas the examiners argument on this occasion is , that his way of rarefaction must be admitted , because neither of the other two can be well made out , his adversaries may with the same reason argue that one of theirs is to be allowed , since his is incumbred with such manifest difficulties . and they may enforce what they say by representing , that the inconveniences that attend his hypothesis about rarefaction are insuperable , arising from the unintelligible nature of the thing itself ; whereas those to which the other wayes are obnoxious , may seem to spring but from mens not having yet discovered what kind of figures and motions of the small particles may best qualifie them to make the body that consists of them capable of a competent expansion . after our authors objections against the two wayes of rarefaction proposed , the one by the vacuists , and the other by the cartesians and others , that admit the solidest bodies , and even glass itself , to be pervious to an aethereal or subtile matter ; he attempts to explicate the manner by which that rigorous rarefaction he teaches is perform'd : and having premised , that the explication of the way how each part of the rarefy'd body becomes extended , depends upon the quality of the parts into which the body is ultimately resolv'd ; and having truly observ'd , that they must necessarily be either really indivisible , or still endlesly divisible ; he endeavours to explicate the aristotelean rarefaction according to those two hypotheses . but , though he thus propose two wayes of making out his rarefaction ; yet besides that they are irreconcilable , he speaks of them so darkly and doubtfully , that it seems less easie to discern which of the two he would be content to stick to , then that he himself scarce acquiesces in either of them . and , first , having told us how rarefaction may be explain'd , in case we admit bodies to be divisible in infinitum , he does himself make such an objection against the infinity of parts in a continuum , as he is fain to give so obscure an answer to , that i confess i do not understand it ; and presume , that not onely the most part of unprejudiced readers will as little acquiesce in the answer as i do ; but even the author himself will not marvel at my confession , since in the same place he acknowledges the answer to be somewhat obscure , and endeavours to excuse its being so , because in that hypothesis it can scarce be otherwise . wherefore i shall onely adde on this occasion , that 't is not clear to me , that even such a divisibility of a continuum as is here supposed would make out the rarefaction he contends for . for , let the integrant parts of a continuum be more or less finite or infinite in number , yet still each part , being a corporeal substance , must have some particle of space commensurate to it ; and if the whole body be rarefied , for instance , to twice its former bigness , then will each part be likewise extended to double its former dimensions , and fill both the place it took up before , and another equal to it , and so two places . the second argument alledged to recommend the hithertomentioned way of explicating rarefaction is , that many learned men , amongst whom he names two , aquinas and suarez , have taught that the same corporeal thing may naturally be , and de facto often is , in the souls of brutes really indivisible and virtually extended . but , though i pay those two authors a just respect for their great skill in scholastical and metaphysical learning ; yet the examiner cannot ignore , that i could make a long catalogue of writers , both ancient and modern , at least as well vers'd in natural philosophy as st. thomas and suarez , who have some of them in express words denyed this to be naturally possible ; and others have declared themselves of the same judgment by establishing principles , with which this conceit of the virtual extension of the indivisible corpuscles is absolutely inconsistent . and though no author had hitherto opposed it , yet i , that dispute not what this or that man thought , but what 't is rational to think , should nevertheless not scruple to reject it now ; and should not doubt to find store of the best naturalists of the same opinion with me , and perhaps among them the examiner himself , who ( however this acknowledgment may agree with the three following chapters of his book ) tells us , ( pag. . ) that juxia probabiliorem sententiam hujusmodi virtualis extensio rei corporea concedenda non est , ut pote soli rei spirituali propria . but to conclude at length this tedious enquiry into the aristotelean way of rarefaction , ( which is of so obscure a nature that it can scarce be either proposed or examined in few words ) i will not take upon me resolutely to affirm which of the two wayes of explicating it ( by atomes or by parts infinitely divisible ) our author declares himself for . but which of them soever it be , i think i have shown that he has not intelligibly made it out : and i make the less scruple to do so , because he himself is so ingenuous as ( at the close of his discourse of the two wayes ) to speak thus of the opinion he prefers ; praestat communi & receptae hactenus in scholis sententiae insistere , quae licet difficultates quidem non clarè solvat , its tamen aperte non succumbit . so that in this discourse of rarefaction , to which our author has so often in the fore-going part of the book referred us , as that which should make good what there seemed the most improbable ; he has but instead of a probable hypothesis needlesly rejected , substituted a doctrine which himself dares not pretend capable of being well freed from the difficulties with which it may be charged ; though i doubt not but other readers , especially naturalists , will think he has been very civil to this obscure doctrine , in saying that difficultatibus non aperte succumbit . as for the other way of explicating rarefaction , namely , by supposing that a body is made up of parts indivisible ; he will not , i presume , deny , but that the objections we formerly made against it are weighty . for according to this hypothesis ( which one would think he prefers , since he makes use of it in the three or four last chapters of his book ) necessariò fatendum est ( sayes he ) unam eandemque partem poni in duplici loco adaequate : cum enim indivisibilis sit , locumque occupet majorem quam prius , necesse est ut tota sit in quolibet puncto totius loci , sive ut per totum illud spatium virtualiter extendatur . so that when he in the very next page affirms , that by this virtual extension of the parts , the difficulties that have for so many ages troubled philosophers may be easily solved , he must give me leave ( who love to speak intelligibly , and not to admit what i cannot understand ) to desire he would explain to me what this extensio virtualis is , and how it will remove the difficulties that i formerly charged upon the aristotelean rarefaction . for the easier consideration of this matter , let us resume what we lately supposed , namely , that in the magdeburgick experiment the half inch of undilated air consisted of a hundred corpuscles ; i demand how the indivisibility of these corpuscles will qualifie them to make out such a rarefaction as the author imagines . for what does their being indivisible do in this case , but make it the less intelligible how they can fill above a hundred parts of space ? 't is easie to fore-see he will answer , that they are virtually extended . but not here to question how their indivisibility makes them capable of being so ; i demand , whether by an atoms being virtually extended , its corporeal substance do really ( i mean adequately ) fill more space then it did before , or whether it do not : ( for one of the two is necessary . ) if it do , then 't is a true and real , and not barely a virtual extension . and that such an extension will not serve the turn , what we have formerly argued against the peripatetick rarefaction will evince ; and our adversary seems to confess as much , by devising this virtual extension to avoid the inconveniences to which he saw his doctrine of rarefaction would otherwise plainly appear expos'd . but if it be said , that when an atome is virtually extended , its corporeal substance fills no more space then before : this is but a verbal shift , that may perhaps amuse an unwary reader , but it will scarce satisfie a considering one . for i demand how that which is not a substance can fill place ; and how this improper and but metaphorical extension will salve the phaenomena of rarefaction : as how the half inch of air at the top of the fore-mentioned globe shall without a corporeal extension fill the whole globe of two thousand times its bigness when the water is suck'd out of it , and act at the lower part of the globe . which last clause i therefore adde , because not onely our author teaches ( pag. . & . ) that the whole globe was filled with a certain thin substance , which by its contraction violently snatch'd up the water into which the neck of the glass was immers'd ; but in a parallel case he makes it his grand argument to prove , that there is no vacuum in the deserted part of the tube in the torricellian experiment , that the attraction of the finger cannot be performed but by some real body . wherefore till the examiner do intelligibly explain how a virtual extension , as it is opposed to a corporeal , can make an atome fill twice , nay , two thousand times more space then it did before ; i suppose this device of virtual extension will appear to unbiass'd naturalists but a very unsatisfactory evasion . two arguments indeed there are which our adversary offers as proofs of what he teaches . the first is , that they commonly teach in the schools , that at least divinitus ( as he speakes ) such a thing as is pleaded for may be done , and that consequently it is not repugnant to the nature of a body . but , though they that either know me , or have read what i have written about matters theological , will , i hope , readily believe , that none is more willing to acknowledge and venerate divine omnipotence ; yet in some famous schools they teach , that it is contrary to the nature of the thing . and that men who think so , and consequently look not upon it as an object of divine omnipotence , may ( whatever he here say ) without impiety be of a differing mind from him about the possibility of such a rarefaction as he would here have , our author may perchance think fit to grant , if he remember that he himself sayes a few pages after , cum tempus sit ens essentialiter successivum , it a ut ne divinitus quidem possint duae ejus partes simul existere , &c. but , not now to dispute of a power that i am more willing to adore then question , i say , that our controversie is not what god can do , but about what can be done by natural agents , not elevated above the sphere of nature . for though god can both create and annihilate , yet nature can do neither : and in the judgment of true philosophers i suppose our hypothesis would need no other advantage to make it be preferred before our adversaries , then that in ours things are explicated by the ordinary course of nature , whereas in the other recourse must be had to miracles . but though our authors way of explicating rarefaction be thus improbable , yet i must not here omit to take notice , that his funiculus supposes a condensation that to me appears incumbred with no less manifest difficulties . for , since he teaches that a body may be condens'd without either having any vacuities for the comprest parts to retire into , or having pores filled with any subtile and yielding matter that may be squeez'd out of them ; it will follow , that the parts of the body to be condens'd do immediately touch each other : which supposed , i demand how bodies that are already contiguous can be brought to farther approximations without penetrating each other , at least in some of their parts . so that i see not how the examiners condensation can be perform'd without penetration of dimensions . a thing that philosophers of all ages have looked upon as by no means to be admitted in nature . and our author himself speaks somewhere at the same rate , where to the question , why the walls that inclose fired gun-powder must be blown asunder ? respondeo ( sayes he ) haec omnia inde accidere , quod pulvis ille sic accensus & in flammam conversus , longe majus spatium nunc occupet quàm prius . unde fit , ut cum totum cubiculum antea fuerit plenissimum , disrumpantur sic parietes , ne detur corporum penetratio . in the magdeburgick experiment he tells us ( as we have heard already ) that the whole capacity of the globe is filled with an extremely thin body . but not now to examine how properly he calls that a rare body , which according to him intercepts neither pores nor any heterogeneous substance , the greater or lesser absence of which makes men call a body more or less dense ; not to insist on this , i say , let us consider , that before the admission of water into the exhausted globe there was , according to him , two thousand half inches of a substance , which , however it was produc'd or got thither , was a true and real body ; and that after the admission of the water there remained in the same globe , besides the water that came in , no more then one half inch of body . since then our author does not pretend ( which if he did , might be easily disproved ) that the one thousand nine hundred ninety nine half inches of matter , that now appear no more , traversed the body of water ; since he will not allow that it gets away through the pores of the glass , i demand , what becomes of so great a quantity of matter ? for that 't is annihilated i suppose he is too rational a man to pretend , ( nor , if he should , would it be at all believ'd ) and to say , that a thousand and so many hundred parts of matter should be retir'd into that one part of space that contains the one half inch of air , is little less incredible : for that space was suppos'd perfectly full of body before , and how a thing can be more then perfectly full , who can conceive ? to dispatch : according to our authors way of condensation , two , or perhaps two thousand , bodles may be crouded into a space that is adequately fill'd by one of them apart . and if this be not penetration of dimensions , i desire to be informed what is so ; and till then i shall leave it to any unprepossess'd naturalist to judge , whether an hypothesis that needs suppose a thing so generally concluded to be impossible to nature , be probable or not ; and whether to tell us that the very same parcel of air , that is now without violence contain'd in half an inch of space , shall by and by fill two thousand times as much room , and presently after shrink again into the two thousandth part of the space it hewly possess'd , be not to turn a body into a spirit , and , confounding their notions , attribute to the former the discriminating and least easily conceivable properties of the later . and this argument is , i confess , with me of that weight , that this alone would keep me from admitting the examiners hypothesis : yet if any happier contemplator shall prove so sharp-sighted , as to devise and clearly propose a way of making the rarefaction and condensation hither to argued against , intelligible to me , he is not like to find me obstinate . nor indeed is there sufficient cause why his succeeding in that attempt should make our adversaries hypothesis preferrable to ours , since that would not prove it either necessary , or so much as sufficient , but onely answer some of the arguments that tend to prove 't is not intelligible . and that we have other arguments on our side then those that relate to rarefaction and condensation , may appear partly by what has been discours'd already , and partly by what we have now to subjoyn . chap. iv. a consideration ( pertinent to the present controversie ) of what happens in trying the torricellian and other experiments , at the tops and feet of hills . there remain then yet a couple of considerations to be oppos'd against the examiners hypothesis , which , though the past discourse may make them be look'd upon as needless , we must not pretermit , because they contain such arguments as may not onely be imployed against our adversaries doctrine , but will very much tend to the confirmation of ours . i consider then further , that the hypothesis i am opposing , being but a kind of inversion of ours , and supposing the spring or motion of restitution in the air to tend inwards , as according to us it tends outwards ; it cannot be , that if the supposition it self were ( what i think i have prov'd it is not ) true , many of the phaenomena would be plausibly enough explicable by it : the same motions in an intermediate body being in many cases producible alike , whether we suppose it to be thrust or drawn ; provided both the endeavours tend the same way . but then we may be satisfied whether the effect be to be ascribed to pulsion or to traction , ( as they commonly speak , though indeed the later seems reducible to the former ) if we can find out an experiment wherein there is reason such an effect should follow , in case pulsion be the cause inquired after , and not in case it be traction . and such an experimentum crucis ( to speak with our illustrious verulam ) is afforded us by that noble observation of monsieur paschall , mentioned by the famous pecquet , and out of him by our author : namely , that the torricellian experiment being made at the foot and in divers places of a very high mountain , ( of the altitude of five hundred fathom or three thousand foot ) he found , that after he had ascended a hundred and fifty fathom , the quicksilver was fallen two inches and a quarter below its station at the mountains foot ; and that at the very top of the hill it had descended above three inches below the same wonted station . whence it appears that the quicksilver being carried up towards the top of the atmosphere , falls down the lower , the higher the place is wherin the observation is made : of which the reason is plain in our hypothesis , namely , that the nearer we come to the top of the atmosphere , the shorter and lighter is the cylinder of air incumbent upon the restagnant mercury ; and consequently the less weight of cylindrical mercury will that air be able to counter-poise and keep suspended . and since this notable phaenomenon does thus clearly follow upon ours , and not upon our adversaries hypothesis ; this experiment seems to determine the controversie betwixt them : because in this case the examiner cannot pretend , as he does in the seventeenth and divers other of our experiments , that the descent of the quicksilver in the tube is caus'd , not by the diminution of the external airs pressure , but from the preternatural rarefaction or distension of that external air ( in the receiver ) when by seeking to restore it self , it endeavours to draw up the restagnant mercury : for in our present case there appears no such forcible dilatation of that air , as in many of the phaenomena of our engine he is pleas'd to imagine . it need therefore be no great wonder , if his adversaries do , as he observes , make a great account of this experiment , to prove that the mercury is kept up in the tube by the resistance of the external aire . nor do i think his answers to the argument drawn from hence will keep them from thinking it cogent . for to an objection upon which he takes notice that they lay so much stress , he replyes but two things ; which neither singly nor together will near amount to a satisfactory answer . but because that though experiments made in very elevated places are noble ones , and of great importance in the controversies about the air , yet there are but very few of those that are qualified to make experiments of that nature , who have the opportunity of making them upon high mountains ; we did with the assistance of an ingenious man attempt a tryal , wherein we hoped to find a sensibly-differing weight of the atmospere , in a far less height then that of an ordinary hill. but in stead of a common tube we made use of a kind of weather-glass , that the included air might help to make the event notable , for a reason to be mentioned ere long ; and in stead of quicksilver we employ'd common water in the pipe belonging to the weather-glass , that small changes in the weight or resistance of the atmosphere in opposit on of the included air might be the more discernable . the instrument we made use of consisted only of a glass with a broad foot and a narrow neck ( a b ) and a slender glass-pipe ( c d ) open at both ends : which pipe was so placed , that the bottom of it did almost , but not quite , reach to the bottom of the bigger glass ( a b ) within whose neck ( a ) it was fastned with a close cement , that both kept the pipe in its place , and hindred all communication betwixt the inward ( i i ) and outward ( k k ) air , save by the cavity of the pipe ( c d ) . now we chose this glass ( a b ) more then ordinarily capacious , that the effect of the dilatation of the included air ( i i ) might be the more conspicuous . then conveying a convenient quantity of water ( h h ) into this glass , we carried it to the leads of the lofty abby-church at westminster , and there blew in a little air to raise the water to the upper part of the pipe , that being above the vessel ( a b ) we might more precisely mark the several stations of the water then otherwise we could . afterward having suffered the glass to rest a pretty while upon the lead , that the air ( i i ) within might be reduc'd to the same state , both as to coldness and as to pressure , with ( k k ) that without , having marked the station of the water ( f ) , we gently let down the vessel by a long string to the foot of the wall , where one attended to receive it ; who having suffer'd it to rest upon the ground , cry'd to us that it was subsided about an inch below the mark ( f ) we had put : whereupon having order'd him to put a mark at this second station of it ( e ) , we drew up the vessel again ; and suffering it to rest a while , we observ'd the water to be re-ascended to or near the first mark ( f ) , which was indeed about an inch above ( e ) the other . and this we did that evening a second time with almost a like success : though two or three dayes after , the wind blowing strongly upon the leads , we found not the experiment to succeed quite so regularly as before ; yet the water alwayes manifestly fell lower at the foot of the wall then it was at the top : which i see no cause to ascribe barely to the differing temperature of the air above and below , as to heat and cold , since according to the general estimate , the more elevated region of the air is , caeteris paribus , colder then that below , which would rather check the greater expansion of the included air at the top of the leads then promote it . but the better to avoid mistakes and prevent objections , we thought fit to try the experiment within the church , and got into a gallery of the same height with the leads : but the upper part of the pipe being casually broken off , we thought fit to order the matter so , that the surface ( g ) of the remaining water in the pipe should be about an inch higher then the surface of the water in the vessel . and then my above-mentioned correspondent letting down the glass , almost as soon as it was setled upon the pavement , kneeling down to see how far it was subsided , i found that not only it was fallen as low as the other water , but that the outward air deprest it so far , as whilest i was looking on , to break in beneath the bottom of the pipe , and ascend through the water in bubbles : after which the glass being drawn up again , my correspondent affirm'd , that the water was very manifestly re-ascended . but because by the unlucky breaking of a glass , we were hindred to observe , as we designed , what would happen as well in a weather-glass , so contriv'd that the weight or pressure of the atmosphere should make no change in it , as in another whose included air was at the top , ( whereas in that we imploy'd the included air was in the lower part , ) and because there happened in our tryals a circumstance or two that seem'd not so devoid of difficulties , but that we think it may require further examination , we design to set down a more particular account of this experiment , ( as how it succeeds with quicksilver instead of water , together with the capacity of the vessel ( a b ) and the bore of the pipe ( c d ) with some other variety of circumstances ) together with the event of the curiosity we had ( which seemed very successful ) to try the torricellian experiment upon the above-mentioned leads , and then let down the tube together with the restagnant mercury to the ground , to observe the increasing altitude of the quicksilver , in the formerly-mentioned appendix to the epistle we have been defending . and it shall suffice us in the mean time that the tryals already mentioned seem to make it evident enough that the atmosphere gravitates more , caeteris paribus , neer the surface of the earth , then in the more elevated parts of the air. for the leads on which we made our tryals were found by measure to be in perpendicular height but threescore and fifteen foot from the ground . to which we shall only add this at present , that once being desirous to observe what we could touching the proportions of the subsidence of the water to the height of its several stations from the ground , purposely carrying down the vessel so as not considerably to heat it , from the leads down the staires to a little window that we guest to be almost half way to the bottom , we there perceived the water to have already subsided about a barley-corns length , notwithstanding that probably in spight of our care , the vessel were a little warmed by the heat of his body that carried it , since by that time we were come to the foot of the wall , the water stood almost at the highest mark ; but after the vessel was suffered to rest a while , it relapsed by degrees to the lowest . and thus much for the first of the things i had to represent in favour of our doctrine . the other particular i shall mention for confirmation of our hypothesis , is that experiment ( which , though it be needless , seems yet more cogent and proper to prevent evasions ) made by the same monsieur paschal , of carrying a weakly-blown foot-ball from the bottom to the top of an high mountain . for that foot-ball swell'd more and more , the higher it was carried , so that it appeared as if it were full blown at the top of the mountain , and gradually growing lank again , as it was carried ; downwards ; so that at the foot of the hill it was flaccid as before . this , i say , having thus happened , we have here an experiment to prove our hypothesis , wherein recourse cannot be had to any forcibly and preternaturally distended body , such as that is pretended to be which remaines in the deserted space of the tube in the torricellian experiment . the other thing which the examiner alledges against our argument from monsieur paschals tryals , is , that supposing it to be true , yet it cannot thence be inferr'd , that the subsidence of the mercury at the top of the hill proceeded from the atmospherical cylinder's being there lighter and less able to sustain the quicksilver . sed dici potest ( sayes he ) ideo sic in vertice montis magis descendisse , quod ibidem esset aura frigidior , aut ex alio temperamento hujusmodi descensum causante . but this solution will not serve the turn : for the coldness of the ambient air ( which yet the experimenters take not notice of ) would rather contract the rarefied substance within the tube , and so draw up the mercury higher , as our author himself teaches us , that 't is from the shrinking of the funiculus occasion'd by the cold that the water in thermometers ascends in cold weather . and whereas the only proof he adds of so improbable an explication is taken from our eighteenth experiment , wherein we relate , that sometimes the quicksilver did sensibly fall lower in colder then in far less cold weather : i answer , that this eighteenth experiment will scarce make more for him then against him : for , as i there take notice that the quicksilver descended in cold weather , so it sometimes descended likewise in hot weather , and rose in cold . and 't is very strange , that in all the observations made , in differing countries and at differing times , it should still so happen that the mercurial cylinder should be shorter near the top of the atmosphere then further from it ; if the resistance of the outward air have nothing to do with the keeping it suspended . and 't is yet more strange , that the foot-ball should in like manner grow turgid and flaccid , according as it is carried into places where it has a shorter or longer pillar of air incumbent on it . i was going to proceed to what remains of this second part of our treatise , but that since i begun this chapter casually meeting with an experiment lately sent in a letter to a very ingenious † acquaintance of his and mine by a very industrious physician * ( who is said to have had the curiosity to try over again many of the experiments of our engine ) and finding it very proper to confirm our newly related experiment made at westminster , and to be of such a nature as we have not in this part of england the opportunity to try the like , for want of hills high enough , i shall ( according to the permission given me ) insert it in this place . and the rather , that as the mountains have by the trials made on them of the torricellian experiment , afforded us a noble proof of the weight of the air ; so they may afford us one of its spring : wherein i hope the phaenomenon of the waters descent will not be ascribed to any attraction made of the water by the violently-distended outward air. and because the experiment was not made by us , but by another , we will set it down in his words , which are these : this fifteenth of october . we took a weather-glass a b , of about two foot in length , and carrying it to the bottom of hallifax hill , the water stood in the shank at thirteen inches above the water in the vessel : thence carrying it thus fill'd , with the whole frame , immediately to the top of the said hill , the water fell down to the point d , viz. an inch and a quarter lower then it was at the bottom of the said hill ; which ( as he rightly inferrs ) proves the elasticity of the air : for the internal air a c , which was of the same power and extension with the external at the bottom of the hill , did manifest a greater elasticity then the mountain-air there * , and so extended it self further by c d. the like experiment , i hear , the same ingenious doctor has very lately repeated , and found the descent of the water to be greater then before . and though some virtuosi have thought it strange , that in an hill far inferiour to the alps and appennines , so short a cylinder of so light al quor as water should fall so much ; yet i see not any reason to distrust upon this ground either his experiment or ours ( lately mention'd to have been made at westminster ; ) but rather to wonder the water fell not more ( if the hill be considerably high : ) for their suspicion seems grounded upon a mistake , as if because the quick-silver in the torricellian experiment made without purposely leaving any air in the tube , would not , at the top of the mention'd hill , have subsided above an inch , if so much , the water , that is near fourteen times lighter , should not fall above a fourteenth part of that space ; whereas in the torricellian experiment , the upper and deserted space of the tube has little or no air left in it , but the correspondent part of the weather-glass was furnish'd with air , whose pressure was little less then that of the atmosphere at the bottom of the hill ; and consequently must be much greater then the pressure of the same atmosphere at the top of the hill , where the atmospherical cylinder's gravity ( upon whose account it presses ) must be much diminish'd by its being made much shorter , and by its consisting of an air less comprest . and thus much for the first of the two considerations wherewith i promised to conclude this second part of the present tract . onely before i proceed i must in a word desire the reader to take notice , that though i have here singled out but one of the nine experiments which the examiner in the . and . chapters reckons up as urg'd by his adversaries ; yet i do not thereby declare my acquiescing in his explications of those phaenomena , but onely leave both them and some other things he delivers about siphons and the magdeburg experiments , to be discours'd by those that are more concerned to examine them , contenting my self to have sufficiently disproved the funiculus which his expositions suppose , and cleared the grounds of explicating such experiments aright . chap. v. two new experiments touching the measure of the force of the spring of air compress'd and dilated . the other thing that i would have considered touching our adversaries hypothesis is , that it is needless . for whereas he denies not that the air has some weight and spring , but affirms that it is very insufficient to perform such great matters as the counterpoising of a mercurial cylinder of . inches , as we teach that it may : we shall now endeavour to manifest by experiments purposely made , that the spring of the air is capable of doing far more then 't is necessary for us to ascribe to it , to salve the phaenomena of the torricellian experiment . we took then a long glass-tube , which by a dexterous hand and the help of lamp was in such a manner crooked at the bottom , that the part turned up was almost parallel to the rest of the tube , and the orifice of this shorter leg of the siphon ( if i may so call the whole instrument ) being hermetically seal'd , the length of it was divided into inches , ( each of which was subdivided into eight parts ) by a straight list of paper , which containing those divisions was carefully pasted all along it : then putting in as much quicksilver as served to fill the arch or bended part of the siphon , that the mercury standing in a level might reach in the one leg to the bottom of the divided paper , and just to the same height or horizontal line in the other ; we took care , by frequently inclining the tube , so that the air might freely passfrom one leg into the other by the sides of the mercury , ( we took ( i say ) care ) that the air at last included in the shorter cylinder should be of the same laxity with the rest of the air about it . this done , we began to pour quicksilver into the longer leg of the siphon , which by its weight pressing up that in the shorter leg , did by degrees streighten the included air : and continuing this pouring in of quicksilver till the air in the shorter leg was by condensation reduced to take up but half the space it possess'd ( i say , possess'd , not fill'd ) before ; we cast our eyes upon the longer leg of the glass , on which was likewise pasted a list of paper carefully divided into inches and parts , and we observed , not without delight and satisfaction , that the quicksilver in that longer part of the tube was . inches higher then the other . now that this observation does both very well agree with and confirm our hypothesis , will be easily discerned by him that takes notice that we teach , and monsieur paschall and our english friends experiments prove , that the greater the weight is that leans upon the air , the more forcible is its endeavour of dilatation , and consequently its power of resistance , ( as other springs are stronger when bent by greater weights . ) for this being considered , it wil appear to agree rarely-well with the hypothesis , that as according to it the air in that degree of density and correspondent measure of resistance to which the weight of the incumbent atmosphere had brought it , was able to counter-balance and resist the pressure of a mercurial cylinder of about . inches , as we are taught by the torricellian experiment ; so here the same air being brought to a degree of density about twice as great as that it had before , obtains a spring twice as strong as formerly . as may appear by its being able to sustain or resist a cylinder of . inches in the longer tube , together with the weight of the atmospherical cylinder , that lean'd upon those . inches of mercury ; and , as we just now inferr'd from the torricellian experiment , was equivalent to them . we were hindered from prosecuting the tryal at that time by the casual breaking of the tube . but because an accurate experiment of this nature would be of great importance to the doctrine of the spring of the air , and has not yet been made ( that i know ) by any man ; and because also it is more uneasie to be made then one would think , in regard of the difficulty as well of procuring crooked tubes fit for the purpose , as of making a just estimate of the true place of the protuberant mercury's surface ; i suppose it will not be unwelcome to the reader , to be informed that after some other tryals , one of which we made in a tube whose longer leg was perpendicular , and the other , that contained the air , parallel to the horizon , we at last procured a tube of the figure exprest in the scheme ; which tube , though of a pretty bigness , was so long , that the cylinder whereof the shorter leg of it consisted admitted a list of paper , which had before been divided into . inches and their quarters , and the longer leg admitted another list of paper of divers foot in length , and divided after the same manner : then quicksilver being poured in to fill up the bended part of the glass , that the surface of it in either leg might rest in the same horizontal line , as we lately taught , there was more and more quicksilver poured into the longer tube ; and notice being watchfully taken how far the mercury was risen in that longer tube , when it appeared to have ascended to any of the divisions in the shorter tube , the several observations that were thus successively made , and as they were made set down , afforded us the ensuing table . a table of the condensation of the air. a a b c d e added to ⅛ makes / / ½ / / / / / / ½ / / / / / — ½ / — / / / ⅞ ½ / / / / / / ½ / / ⅗ / / — ½ / / / / / / ¾ / / / ½ / / / ¼ / / / / / — / — / / ½ / / ⅔ ¼ / / / / / ⅜ ¾ / / ⅕ ½ / / / ¼ / / / / / / a a. the number of equal spaces in the shorter leg , that contained the same parcel of air diversly extended . b. the height of the mercurial cylinder in the longer leg , that compress'd the air into those dimensions . c. the height of a mercurial cylinder that counterbalanc'd the pressure of the atmosphere . d. the aggregate of the two last columns b and c , exhibiting the pressure sustained by the included air. e. what that pressure should be according to the hypothesis , that supposes the pressures and expansions to be in reciprocal proportion . for the better understanding of this experiment it may not be amiss to take notice of the following particulars : . that the tube being so tall that we could not conveniently make use of it in a chamber , we were fain to use it on a pair of stairs , which yet were very lightsom , the tube being for preservations sake by strings so suspended , that it did scarce touch the box presently to be mentioned . . the lower and crooked part of the pipe was placed in a square wooden box , of a good largness and depth , to prevent the loss of the quicksilver that might fall aside in the transfusion from the vessel into the pipe , and to receive the whole quicksilver in case the tube should break . . that we were two to make the observation together , the one to take notice at the bottom how the quicksilver rose in the shorter cylinder , and the other to pour in at the top of the longer , it being very hard and troublesome for one man alone to do both accurately . . that the quicksilver was poured in but by little and little , according to the direction of him that observed below , it being far easier to pour in more , then to take out any in case too much at once had been poured in . . that at the beginning of the operation , that we might the more truly discern where the quicksilver rested from time to time , we made use of a small looking-glass , held in a convenient posture to reflect to the eye what we desired to discern . . that when the air was so compress'd , as to be crouded into less then a quarter of the space it possess'd before , we tryed whether the cold of a linen cloth dipp'd in water would then condense it . and it sometimes seemed a little to shrink , but not so manifestly as that we dare build any thing upon it . we then tryed likewise whether heat would notwithstanding so forcible a compressure dilate it , and approching the flame of a candle to that part where the air was pent up , the heat had a more sensible operation then the cold had before ; so that we scarce doubted but that the expansion of the air would notwithstanding the weight that opprest it have been made conspicuous , if the fear of unseasonably breaking the glass had not kept us from increasing the heat . now although we deny not but that in our table some particulars do not so exactly answer to what our formerly intimated hypothesis might perchance invite the reader to expect ; yet the variations are not so considerable , but that they may probably enough be ascribed to some such want of exactness as in such nice experiments is scarce avoidable . but for all that , till further tryal hath more clearly informed me , i shall not venture to determine whether or no the intimated theory will hold universally and precisely , either in condensation of air , or rarefaction : all that i shall now urge being , that however , the tryal already made sufficiently proves the main thing for which i here alledge it ; since by it 't is evident , that as common air when reduc'd to half its wonted extent , obtained near about twice as forcible a spring as it had before ; so this thus-comprest air being further thrust into half this narrow room , obtained thereby a spring about as strong again as that it last had , and consequently four times as strong as that of the common air. and there is no cause to doubt , that if we had been here furnisht with a greater quantity of quicksilver and a very strong tube , we might by a further compression of the included air have made it counter-balance the pressure of a far taller and heavier cylinder of mercury . for no man perhaps yet knows how near to an infinite compression the air may be capable of , if the compressing force be competently increast . so that here our adversary may plainly see that the spring of the air , which he makes so light of , may not onely be able to resist the weight of . inches , but in some cases of above an hundred inches of quicksilver , and that without the assistance of his funiculus , which in our present case has nothing to do . and to let you see that we did not ( a little above ) inconsiderately mention the weight of the incumbent atmospherical cylinder as a part of the weight resisted by the imprisoned air , we will here annex , that we took care , when the mercurial cylinder in the longer leg of the pipe was about an hundred inches high , to cause one to suck at the open orifice ; whereupon ( as we expected ) the mercury in the tube did notably ascend . which considerable phaenomenon cannot be ascribed to our examiners funiculus , since by his own confession that cannot pull up the mercury , if the mercurial cylinder be above . or . inches of mercury . and therefore we shall render this reason of it , that the pressure of the incumbent air being in part taken off by its expanding it self into the suckers dilated chest ; the imprison'd air was thereby enabled to dilate it self manifestly , and repel the mercury that comprest it , till there was an equality of force betwixt the strong spring of that comprest air on the one part , and the tall mercurial cylinder , together with the contiguous dilated air , on the other part . now , if to what we have thus delivered concerning the compression of air we adde some observations concerning its spontaneous expansion , it will the better appear how much the phaenomena of these mercurial experiments depend upon the differing measures of strength to be met with in the airs spring , according to its various degrees of compression and laxity . but , before i enter upon this subject , i shall readily acknowledge that i had not reduc'd the tryals i had made about measuring the expansion of the air to any certain hypothesis , when that ingenious gentleman mr. richard townely was pleased to inform me , that having by the perusal of my physico-mechanical experiments been satisfied that the spring of the air was the cause of it , he had endeavoured ( and i wish in such attempts other ingenious men would follow his example ) to supply what i had omitted concerning the reducing to a precise estimate how much air dilated of it self loses of its elastical force , according to the measures of its dilatation . he added , that he had begun to set down what occurred to him to this purpose in a short discourse , whereof he afterwards did me the favour to shew me the beginning , which gives me a just curiosity to see it perfected . but , because i neither know , nor ( by reason of the great distance betwixt our places of residence ) have at present the opportunity to enquire , whether he will think fit to annex his discourse to our appendix , or to publish it by it self , or at all ; and because he hath not yet , for ought i know , met with fit glasses to make an any-thing-accurate table of the decrement of the force of dilated air ; our present design invites us to present the reader with that which follows , wherein i had the assistance of the same person that i took notice of in the former chapter , as having written something about rarefaction : whom i the rather make mention of on this occasion , because when he first heard me speak of mr. townley's suppositions about the proportion wherein air loses of its spring by dilatation , he told me he had the year before ( and not long after the publication of my pneumatical treatise ) made observations to the same purpose , which he acknowledged to agree well enough with mr. townley's theory : and so did ( as their author was pleased to tell me ) some tryals made about the same time by that noble virtuoso and eminent mathematician the lord brouncker , from whose further enquiries into this matter , if his occasions will allow him to make them , the curious may well hope for something very accurate . a table of the rarefaction of the air. a b c d e / subttracted from ¾ leaves ¾ ¾ / ⅝ ⅛ ⅚ ⅜ ⅜ ⅞ / / / ⅝ ⅛ / ⅛ ⅝ / ⅞ ⅞ / / / ¼ / / / ⅜ / / / / / ⅛ ⅝ / / / ⅛ / / ● / ⅞ ⅞ / ● / ● / / / / / ⅜ ⅜ / / / / a. the number of equal spaces at the top of the tube , that contained the same parcel of air. b. the height of the mercurial cylinder , that together with the spring of the included air counterbalanced the pressure of the atmosphere . c. the pressure of the atmosphere . d. the complement of b to c , exhibiting the pressure sustained by the included air. e. what that pressure should be according to the hypothesis . to make the experiment of the debilitated force of expanded air the plainer , 't will not be amiss to note some particulars , especially touching the manner of making the tryal ; which ( for the reasons lately mention'd ) we made on a lightsome pair of stairs , and with a box also lin'd with paper to receive the mercury that might be spilt . and in regard it would require a vast and in few places procurable quantity of quicksilver , to employ vessels of such kind as are ordinary in the torriccllian experiment , we made use of a glass-tube of about six foot long , for that being hermetically sealed at one end , serv'd our turn as well as if we could have made the experiment in a tub or pond of seventy inches deep . secondly , we also provided a slender glass-pipe of about the bigness of a swans quill , and open at both ends : all along which was pasted a narrow list of paper divided into inches and half quarters . thirdly , this slender pipe being thrust down into the greater tube almost fill'd with quicksilver , the glass helpt to make it swell to the top of the tube , and the quicksilver getting in at the lower orifice of the pipe , fill'd it up till the mercury included in that was near about a level with the surface of the surrounding mercury in the tube . fourthly , there being , as near as we could guess , little more then an inch of the slender pipe left above the surface of the restagnant mercury , and consequently unfill'd therewith , the prominent orifice was carefully clos'd with sealing wax melted ; after which the pipe was let alone for a while , that the air dilated a little by the heat of the wax , might upon refrigeration be reduc'd to its wonted density . and then we observ'd by the help of the above-mentioned list of paper , whether we had not included somewhat more or somewhat less then an inch of air , and in either case we were fain to rectifie the error by a small hole made ( with an heated pin ) in the wax , and afterwards clos'd up again . fifthly , having thus included a just inch of air , we listed up the slender pipe by degrees , till the air was dilated to an inch , an inch and an half , two inches , &c. and observed in inches and eighths , the length of the mercurial cylinder , which at each degree of the airs expansion was impell'd above the surface of the restagnant mercury in the tube . sixthly , the observations being ended , we presently made the torricellian experiment with the above-mention'd great tube of six foot long , that we might know the height of the mercurial cylinder , for that particular day and hour ; which height we found to be ¾ inches . seventhly , our observations made after this manner furnish'd us with the preceding table , in which there would not probably have been found the difference here set down betwixt the force of the air when expanded to double its former dimensions , and what that force should have been precisely according to the theory , but that the included inch of air receiv'd some little accession during the tryal ; which this newly-mention'd difference making us suspect , we found by replunging the pipe into the quicksilver , that the included air had gain'd about half an eighth , which we guest to have come from some little aerial bubbles in the quicksilver , contain'd in the pipe ( so easie is it in such nice experiments to miss of exactness . ) we try'd also with . inches of air shut up to be dilated ; but being then hindred by some unwelcome avocations to prosecure those experiments , we shall elsewhere , out of other notes and tryals ( god permitting ) set down some other accurate tables concerning this matter . by which possibly we may be assisted to resolve whether the atmosphere should be look'd upon ( as it usually is ) as a limited and bounded portion of the air ; or whether we should in a stricter sense then we did before , use the atmosphere and aereal part of the world for almost equivalent terms ; or else whether we should allow the word atmosphere some other notion in relation to its extent and limits ; ( for as to its spring and weight , these experiments do not question , but evince them . ) but we are willing , as we said , to referre these matters to our appendix , and till then to retain our wonted manner of speaking of the air and atmosphere . in the mean time ( to return to our last-mention'd experiments ) besides that so little a variation may be in great part imputed to the difficulty of making experiments of this nature exactly , and perhaps a good part of it to something of inequality in the cavity of the pipe , or even in the thickness of the glass ; besides this , i say , the proportion betwixt the several pressures of the included air undilated and expanded , especially when the dilatation was great ( for when the air swell'd but to four times its first extent , the mercurial cylinder , though of near . inches , differ'd not a quarter of an inch from what it should have been according to mathematical exactness ) the proportion , i say , was sutable enough to what might be expected , to allow us to make this reflection upon the whole , that whether or no the intimated theory will hold exactly , ( for about that , as i said above , i dare determine nothing resolutely till i have further considered the matter ) yet since the inch of air when it was first included was shut up with no other pressure then that which it had from the weight of the incumbent air , and was no more comprest then the rest of the air we breathed and moved in ; and since also this inch of air , when expanded to twice its former dimensions , was able with the help of a mercurial cylinder of about . inches to counterpoise the weight of the atmosphere , which the weight of the external air gravitating upon the restagnant mercury was able to impell up into the pipe , and sustain above twenty eight inches of mercury when the internal air by its great expansion had its spring too far debilitated to make any considerable ( i say considerable , for it was not yet so dilated as not to make some ) resistance : since , i say , these things are so , the free air here below appears to be almost as strongly comprest by the weight of the incumbent air as it would be by the weight of a mercurial cylinder of twenty eight or thirty inches ; and consequently is not in such a state of laxity and freedom as men are wont to imagine ; and acts like some mechanical agent , the decreement of whose force holds a stricter proportion to its increase of dimension , then has been hitherto taken notice of . i must not now stand to propose the several reflections that may be made upon the foregoing observations touching the compression and expansion of air ; partly because we could scarce avoid making the historical part somewhat prolix ; and partly because i suppose we have already said enough to shew what was intended , namely , that to solve the phaenomena there is not of our adversaries hypothesis any need : the evincing of which will appear to be of no small moment in our present controversie , to him that considers , that the two maine things that induced the learned examiner to reject our hypothesis are , that nature abhors a vacuum , and that though the air have some weight & spring , yet these are insufficient to make out the known phaenomena ; for which we must therefore have recourse to his funiculus . now as we have formerly seen , that he has not so satisfactorily disproved as resolutely rejected a vacuum , so we have now manifested that the spring of the air may suffice to perform greater things then what our explication of the torricellian experiments and those of our engine obliges us to ascribe to it . wherefore since besides the several difficulties that incumber the hypothesis we oppose , and especially its being scarce , if at all , intelligible , we can adde that it is unnecessary ; we dare expect that such readers as are not byass'd by their reverence for aristotle or the peripatetick schools , will hardly reject an hypothesis which , besides that it is very intelligible , is now prov'd to be sufficient , only to imbrace a doctrine that supposes such a rarefaction and condensation , as many famous naturalists rejected for its not being comprehensible , even when they knew of no other way ( that was probable ) of solving the phaenomena wont to be explicated by it . the iii. part. wherein what is objected against mr. boyle's explications of particular experiments , is answered . and now we are come to the third and last part of our defence ; wherein we are to consider what our examiner is pleas'd to object against some passages of our physicho-mechanical treatise . but though this may seem the only part wherein i am particularly concern'd ; yet perhaps we shall find it , if not the shortest , at least the easiest , part of our task . partly , because our author takes no exceptions at the experiments themselves , as we have recorded them ( which from an adversary , who in some places speaks of them as an eye-witness , is no contemptible testimony that the matters of fact have been rightly delivered : ) and partly , because there are divers experiments which , together with their explications , the examiner has thought fit to leave untoucht , and thereby allows us to do so too : and partly also , because that ( as to divers of those experiments upon which he animadverts ) he does not pretend to shew that our explications are ill deduc'd or incongruous to our principles ; but only that the phaenomena may be explain'd either better or as well by his hypothesis , whereof he supposes himself to have demonstrated the truth , together with the erroneousness of ours , in the other parts of his book , especially the third , fourth and fifth chapters . so that after what we have said to vindicate the hypothesis we maintain , and take away our authors imaginary funiculus ; it will not be requisite for us on such occasions to examine his particular assertions and explications . which advertisement we hope the reader will be pleased to bear in mind , and thereby save himself and us the trouble of a great deal of unnecessary repetition . wherefore presuming he will do so , we shall not stay to examine the first and second corollaries , which in his . chapter he annexes to the manner of emptying our receiver by our pump . neither should we say any thing as to his third and last corollary , but that we think fit to desire the reader to take notice , that according to what he teaches in that place , the more the air is rarefied , the more forcibly it is able to contract it self . a defence of our . and . experiments . and to proceed now to his chapter , which he intitles de experiment is boyleanis , we shall find according to what we lately noted , that against the first experiment he objects nothing save that , if one of the fingers be applied to the orifice of the valve when the pump is freed from air , the experimenter shall feel to his pain that the sucker is not thrust inward by the external air , but , as the finger , drawn inward by the internal . but this phaenomenon of the intrusion of the finger into a cavity , where it finds no resistance , having been formerly accounted for according to our hypothesis , we shall not need to repeat our explication of it ; though this mistaken phaenomenon supplies our adversary with divers of his following animadversions , and indeed with a great part of his book . and accordingly his objection against our second experiment being of the same nature with that against the first , requires but the same answer : for it will not alter the case that he adds upon this experiment , hoc esse discrimen manifestum inter pressionem & suctionem , quod suctio efficiat hujusmodi adhaesionem , pressio autem minimè ; since to say so is but to affirme , not to prove . the . experiment . what our author would except against the . experiment he ought to have more intelligibly exprest : for whereas of a discourse wherein i deliver several particulars , he onely sayes that nullatenus satisfacit , ut legenti constabit ; i would not do the reader the injury to suspect him of taking this proofless assertion for a rational confutation ; especially since upon the review of that third experiment i find nothing that agrees not with my hypothesis , however it may disagree with the examiners . but , to consider the explication he substitutes in the room of our doctrine , which he rejects , he gives it us in these words ; hoc quoque experimentum principiis nostris optimè convenit : cum enim per illam emboli depressionem aër in cavitate brachii inclusus separetur ab eodem brachio , descendatque simul cum embolo ( uti de aqua simul cum argento vivo descendente capite decimo tertio vidimus ) fit ut in tota illa depressione , novae semper ab aëre illo desoendente supersicies diripiantur simul & extendantur , ut ibidem de aqua est explicatum : cum itaque aeque facile diripiantur & extendantur hujusmodi superficies in fine depressionis ac initio , mirum non est quod eadem utrobique sentiatur deprimendi difficultas . by which though he seems to intend an opposition to that part of the third experiment which i oppos'd not against his opinion , but that of some learned vacuists : yet ( not to mention that he seems to have somewhat mistaken my sense ) he offers nothing at all to invalidate my inference against them ; but instead of that proposes a defence of his own opinion , which supposes the truth of his disproved hypothesis , and is either unsatisfactory even according to that , or else disagrees with what himself hath taught us but a little before . for 't is evident that the more the sucker is depress'd , the more the cylinder is exhausted of air. and in his third corollary ( which we lately desired the reader to observe ) speaking of the air in the receiver ( and the case is the same with the air in the cylinder ) he affirms more then once , eo magis extendi ac rarefieri aërem relictum , quo plus inde exhauritur , majoremque proinde acquirere vim sese contrahendi . whereas here he would have us believe , that the little internal air that was in the cavity of the shank of the stop cock , does as strongly retract the sucker , or , which in our case is all one , refist its depression , when the sucker is yet near the top of the cylinder , ( and consequently when the included air is but a little dilated ) as when the same sucker being forced down to the lower part of the cylinder , the same portion of remaining air must be exceedingly more distended . the . experiment . in the fourth experiment , touching the swelling of a bladder upon the removal of the ambient air ; and proportionably to that removal our author objects nothing against the explication we give of it by the spring of the air included in the bladder , and distending it according as the pressure of the ambient air is weakned . but he endeavours also to explicate it his way , to which he sayes this circumstance does excellently agree , that upon the regress of the external air into the receiver , the tumid bladder immediately shrinks , because ( saith he ) by such ingress of the external air , the air in the receiver , which drew the sides of the bladder outward from the middle of it , is relax'd . which explication whether it be more natural then ours ( that ascribes the shrinking of the bladder to the pressure of the air that is let into the receiver ) let the reader judge , who has considered what we have formerly objected against the examiners funiculus , and the relaxation of it upon the admission of air. as for the reason likewise he adds , why a perforated bladder does not also swell , namely , that by the hole , how little soever , the included air is suck'd out by the rarefi'd ambient , we leave it to the impartial reader to consider whether is the more genuine explication , either ours ( against which he has nothing to object ) or his , which to make clearly out he ought ( according to what we formerly noted disputing against his funiculus ) to shew us what kind of strings they are ; which though , according to him , strongly fastned to the inside of the receiver and the superficies of the bladder , must draw just as forcibly one as another , how long soever they be without the bladder in comparison of those that within the bladder draw so as to hinder the diduction of its sides . for experience shews , that in a perforated bladder the wrinkles continue as if there were no drawing at all . and though he could describe how such a string may be context , yet our explication will have this advantage in point of probability above his , that whereas he denies not that the air has spring and weight , as we deny his funiculus to have any other then an imaginary existence ; and whereas he acknowledges that by the instrument the air about the bladder is exhausted ; to shew that there needs no more then that , and consequently no funiculus , to draw asunder the sides of the bladder , we can confirm our explication by the formerly mentioned experiment of the ingenious paschall , who carrying a flaccid foot-ball from the bottom to the top of a high mountain , found it to swell proportionably as he ascended , and as the weight and pressure of the ambient air decreased , and likewise to shrink again as he descended . and yet in this case there is no recourse to be had to a funiculus of violently-rarefi'd air to draw asunder every way the sides of the foot-ball . but however the examiner will be able to defend his explication , it may suffice us that he has objected nothing against ours . the . experiment . against the cause we assign of the fifth experiment he likewise objects nothing , but onely ascribes the breaking of the bladder to the self-contraction of the rarefi'd air in the receiver . and therefore referring the reader to what we have newly said about the last experiment , we will with our author pass over the sixth and seventh , to which he has no quarrel , and proceed to the eighth . the . experiment . this is that wherein we mention our having broke a glass-receiver , which was not globular , by the exhaustion of most of the inward air , whereby its debilitated pressure became unable to resist the unweakned pressure of the outward air. but this explication the examiner confidently rejects in these words , at profecto non videtur credibile , mollissimum hunc aërem tam vehementer vitrum ( tantae praesertim crassitudin is quantae ibidem dicitur ) undique sic comprimere ut illud perfring at : as if it were more credible that the little air within ( which , according to him , is so much thinner then common air ) should be able to act more powerfully upon the glass then the air without , which himself confesses to be a heavy body , and which not onely reaches from the surface of the earth to the top of the highest mountains , but which ( as may not improbably be argued from what we have elsewhere delivered ) may , for ought we know to the contrary , be heaped upon the receiver to the height of some hundreds of miles , nay , to i know not how many thousands , in case the atmosphere be not a bounded port on of the air , but reach as high as it. as for the explication he substitutes in these words , verius itaque respondetur , ideo sic fractum esse illud vitrum , quia per exhaustionem illam latera ejus vehementius introrsum sint attracta , quam ut ob figuram illam resistendo minus idoneam resistere potuerunt . cum enim inclusus aër lateribus vitri firmissimè adhaereat , nihil aliud erit aërem illum sic exhaurire , quam satagere latera vitri introrsum flectere : by what we have already discoursed about the funiculus , the reader may easily discern what is to be answered . nor does our author here shew us any way by which his imaginary strings should take such fast hold of the sides of the glass , as to be able to draw them together notwithstanding the resistance they find from the close texture of the body to be broken . the . experiment . our explication of the ninth experiment he handles very severely : for having briefly recited it , he proposes his objection against it thus , sed profecto nimis longè videtur hoc à veritate recedere : potestque vel inde solum satis refutari ; quia si tanta sit pressura aeris sic per tubum illum in phialam descendent is , ut ipsam phialam perfringat , deberet profecto inclusam aquam , cui immergitur ille tubus , valde quoque ante fractionem phialae commovere , bullulasque in eadem excitaro , &c. ut constat , siquis , insufflando per illum tubulum , aquam vel mediocriter sic premat . at certum est aquam , antequam frangatur sit phiala , nec tantillum moveri : ut experienti constabit . but , i do confess , i do for all this think our explication more true , then well considered by our author . for the putting of water into the vial that was broken , was done ( as is clearly intimated in the beginning of our narrative ) upon a particular design ( as indeed we tryed divers other things with our engine , not so much with immediate reference to the spring of the air , as to make use of such tryals in some other of our writings . ) and accordingly in the second tryal mentioned in the same experiment the water was omitted . but , notwithstanding this water , the sides of the glass being exposed to the pressure of the atmosphere , had that whole pressure against them before the exhaustion of the receiver ; so that there needed no such blowing in of the air afresh as our author imagines , to effect the breaking of the vial , it being sufficient for that purpose , that the pressure against the convex superficies of it was taken off by the exhaustion of the receiver , the pressure against the concave superficies remaining as great as ever . and therefore we need not altogether deny what the examiner sayes , that licet clausus superne fuisset tubulus ille , codem tamen modo fracta sine dubio , fuisset phiala . for , since in such cases the air ( as we have often taught ) is shut up with the whole pressure of the atmosphere upon it , it may almost as easily break the glass as if it were unstopt . and accordingly we mention in the . experiment the breaking of a thin glass hermetically seal'd upon the recess of the ambient air. but , how confidently soever our author speaks , i thought fit to adde the word almost , because we observed in the . experiment , that such thin vials ( and thick ones will not break ) are subject upon the withdrawing of the ambient air to retch a little , whereby the spring of the air within the vial might in some cases ( i say , in some ) be so far weakned as not to be able to break it , unless assisted by the pressure of the atmosphere wherewith it communicates , and which leans upon it . and when the vial does actually begin to break , then the pursuing pressure of the outward air upon the yielding air within the vial may help to throw the parts of the glass more forcibly asunder . all the experiments from the . to the . exclusively our examiner leaving uncensured , we may with him , advance to the consideration of the . the . experiment defended . in this we relate how , when we made the torricellian experiment , we shut up the restagnant mercury together with the tube and the suspended mercurial cylinder ( of about . inches ) in our receiver , that by drawing off and letting in the air at pleasure upon the restagnant mercury , and consequently weakning and increasing its pressure , we might make it more clearly appear then hither to had been done by experiment , that the suspension of the mercurial cylinder , and the height of it , depended upon the greater or lesser pressure of the air. but against our explication of this experiment ( which has had the good fortune to convince and satisfie many ingenious men ) the examiner objects nothing in particular , contenting himself to have recourse here also to his funiculus . yet two observations of ours he is pleased to take notice of . the first is , that though the quicksilver were exactly shut up into our receiver after the manner newly declared , yet the suspended quicksilver did not descend : whence having said that i argue , that it is now sustained not by the counterpoise of the atmosphere , but by the spring of the air shut up in the receiver , he subjoyns onely this , sed rectius sane infertur , cylindrum illum nihil ibidem antea praestitisse . but whether this be not gratis dictum we leave the reader to collect from what we have formerly discourst in the second part of this defence of the spring of the air ; especially from that experiment ; by which it appears , that spring may sustain a far higher cylinder of quick-silver . in the second observation he mentions of ours , he summarily recites our explication of the descent and ascent of the mercury in the tube , by the debilitated and strengthned spring of the air. but without finding fault with our application of that principle to the phaenomena , he sayes that he has sufficiently refuted the principle it self in the fourth chapter , ( which how well he has done we have already seen ) and therefore explicates the matter thus ; dico igitur ( sayes he ) argentum per illam exhaustionem sic in tubo descendere , quod deorsum traha●ur ab aëre qui incumbit argento restagnanti : siquidem incumbens ille aër jam per exhaustionem valde rarefactus & extensus , sese vehementer contrahit , & contrahendo conatur etiam subjectum sibi argentum restagnans è suo vasculo elevare , unde fit ut ( argento illo restagnante minus jam gravitante in fundum sui vasculi ) argentum quod est in tubo descendat ; ut per se patet . adeoque mirum non est , quod , ingrediente postea aëre externo , rursum argentum ascendat , cum per illum ingressum vis illa sic elevans argentum restagnans debilitetur . but this explication supposing such a funiculus as we have already shewn to be but fictitious , the reader will easily gather what is to be judged of it from what has been already delivered . wherefore i shall onely subioyn , that by this explication , were it admitted , there is onely an account given of that part of our seventeenth experiment which relates to the descent of the mercury below its wonted height , and its re-ascent to it . but as for our having , by the forcing in some more air into the receiver , impell'd the quicksilver to a considerably-greater height then 't is wont to be sustain'd at in the torricellian experiment , i confess i understand not how the examiner gives an account of it in the following words , ( which are immediately annex'd to those we last recited of his , and which are all that he employes to explicate this notable phaenomenon ) atque hinc etiam redditur ratio alterius quod ibidem quoque notaîur , nempe quod per violentam intrusionem aëris externt in recipientem , ascenderit argentum notabiliter supra digitos ½ . nam sicut per extractionem aëris argentum infra stationem detrahitur , sic etiam per intrusionem novi supra eandem elevabitur . for in this passage i see not how he himself does not rather repeat the matter of fact , then give any account how it is perform'd . and if it be alledged on his behalf , that according to his principles it may be said that , upon the pressure of the adventitious air upon the restagnant mercury , the funiculus in the tube , that was not able before to draw it up above ½ . inches , is now enabled to draw it up higher ; i demand upon what account this new air does thus press against the restagnant mercury , and impell up and sustain that in the tube . it will not be said that 't is by its weight ; for as much mercury as may be thus impell'd up above the usual station will weigh a great many times more then the air forc'd into the receiver . and therefore it remains that the additional air counterpoises the additional mercury by its spring . and if we consider withall , that there 's no reason to doubt , ( especially considering what we have formerly delivered upon tryal touching the power of comprest air to impell up quicksilver ) but that , had we not been afraid of breaking our vessel , we might by forcing more air into the receiver have impell'd it up to the top of the tube , and kept it there ; we shall scarce deny but that , supposing there could be no such funiculus as our examiner's in rerum natura , the pressure of the incumbent air alone might suffice to keep a correspondent cylinder of mercury suspended : and that without any attraction of the restagnant mercury by a funiculus of violently distended air in the receiver , the quicksilver in the tube may be made to rest at any height greater or lesser , provided it exceed . inches , onely because its weight is just able to counterbalance the pressure of the contiguous air. i know not whether i may not adde ( to express an unwillingness to omit what some may think proper to do my adversary right ) that it may be said for the examiner , that he in the . page acknowledging with us a power in the air to recover its due extension if it be crouded into less room then its disposition requires ; a man may from that principle solve the phaenomena in question by saying , that the air in the receiver being forcibly comprest by the intrusion of fresh air into the same vessel , does by its endeavour to recover its due expansion press upon the restagnant mercury , and force up some of it into the tube . but this explication , though it agree with what the author teaches in a place very distant from his notes upon our . experiment , now under debate ; yet still 't is not clear to me how , by what he sayes in these notes , the phaenomenon is accounted for as the word hinc imports it to be . but otherwise i need not quarrel with the explication , since without recurring to the funiculus for the sustaining of the additional mercury , the solution of the phaenomenon is given upon the same principle that i employ . the . experiment . our examiner in his animadversion upon the . experiment , having recited my conjecture at the cause why a cylinder of mercury did in winter rise and fall in the tube , sometimes as water is wont to do in a weather-glass , according to the laws of heat and cold , and sometimes quite contrary thereunto ; adds , that this experiment does strongly enough overthrow our hypothesis of the atmospherical cylinder , and clearly shew that the quicksilver is not sustained by it : nam ( sayes he ) si hic ab eo sustentatum fuisset , debuisset potius frigidiore tempore ascendere quam descendere , eo quod aër tunc multo densior esset & gravior . itaque non sustentatur argentū ab aër is aequipondio , ut asseritur . and by the same argument he concludes against the mercury's being sustained by the spring of the air. but in his animadversions upon this experiment he seems to have been too forward to reprehend ; for he neither well confutes my conjecture , nor substitutes so much as a plausible one in the stead of it . and as to his objection i answer , first , that it doth not conclude : because that as sometimes the quicksilver in the tube did rise in warmer , and fall in colder , weather ; so at other times it did rather emulate the ascent and descent of water in a weather-glass . secondly , though it be true , that cold is wont to condense this or that parcel of air , and that a parcel of air may be made heavier by condensation ; yet that is in regard of the ambient air that retains its wonted laxity , in which the condensed air is weighed . but our author has not yet proved , that in case the cold of the winter should condense the whole incumbent atmosphere , it would then gravitate sensibly more upon the restagnant quicksilver then before . as a pound of wooll will not sensibly vary its weight , though the hairs whereof it is composed be made to lye sometimes in a looser , sometimes in a closer , order . and , thirdly , this objection does as little agree with his doctrine as with my conjecture : for in the . page , where he gives us an account according to his principles of the rising and falling of water in a weather-glass , and compares it with the suspension of quicksilver , he tells us , hinc fit quod , contracto hoc funiculo per frigus , aqua illa tempore frigido ascendat , descendat autem tempore calido , eo quod per calorem funiculus ille dilatetur . so that , according to the examiner himself , the quicksilver ought to have ascended in colder , and descended in warmer , weather . now , although i proposed my thoughts of the difficult phaenomenon under consideration but as a conjecture , and therefore shall be ready to alter them , either upon further discovery , or better information ; yet i see not why it should be post-posed to the examiner's , who , though he rejects our explication , substitutes no other then what may be gathered from these words , ego certe non dubito quin dentur hujusmodi occultae causae , quibus funiculus ille subtilis , quo in tubo suspenditur argentum ( ut dictum est capite decimo ) modo producatur , modo abbrevietur , &c. sicque argentum nunc demittat , nunc elevet . for , since we have made it probable that the copious fumes , sometimes suddenly ascending into the air , and rolling up and down in it , sometimes sensibly altering ( if good authors may be credited ) the refraction of it , and since some other causes , mentioned in our eighteenth experiment , may alter the density and gravity of the air that leans upon the restagnant mercury ; i suppose the reader will think it more intelligible and probable , that alterations , other then those produced by heat and cold , may happen to the incumbent atmosphere , which freely communicates with the neighbouring air , and may thereby become sometimes more stufft , and sometimes more destitute of adventitious exhalations ; then that such changes should happen to a funiculus included in glass , which according to our author is impervious to the subtilest steams that are , and concerning which he offers not so much as a conjecture upon what other account it can happen to be sometimes contracted , and sometimes stretch'd . the . experiment . upon this the examiner has onely this short animadversion , in decimo nono ostendit aquam eodem modo per exhaustionem recipient is descendere , quo in praecedente descendere ostender at argentum vivum ; cujus cum eadem sit ratio , non est cur amplius ei insistamus . in which words since he offers nothing new or peculiar to shew any incongruity in our explication to our principles , which agree very well with the new phaenomena of the experiment ; we are content to leave the reader to judge of the hypotheses themselves , which of the two is the more probable , either ours , that onely requires that the air in the receiver should equally resist a cylinder of water and of quicksilver , when their weight is but the same , though their altitudes be not ; or the examiner's , which exacts that ( according to what we formerly elsewhere noted ) bodies of such differing nature and texture as quicksilver and water should need but just the same weight or strength to rarefie them into a funiculus . the . experiment . in his examen of this experiment our author makes me infer from the phaenomena he repeats , that not onely the air , but the water also has a spring . but though i suspect not that he does wilfully mistake my sense , yet by what i write in this and the following experiments the reader may well enough perceive , that i spoke but very doubtfully of a spring in the water ; nay , and that i did in the . page expresly teach , that the intumescence of it might ( at least in great part ) proceed from that of the small parcels of air , which i thought to be usually harboured in the body of that liquor . but whereas i ascribe the appearance of the bubbles in the water to this , that upon the exhaustion of some of the air incumbent on the water , the pressure of what remains is much debilitated , whereby the little particles of air lurking in the water are allowed to expand themselves into bubbles ; he rejects this explication as manifestly false : nam ( sayes he ) si it a sieret , deberent profecto hujusmodi bullulae non è fundo vasis sic ascendere , ( uti tam in hoc quam in sequentibus experiment is in quibus de istis bullis agitur semper asseritur ) sed è superiore parte aquae , ubi minus premuntur , ut per se est manifestum . but why he should be here so peremptory i confess i do not , for all this objection , yet see : for in the bottom of the next page he sayes , he will not deny but that aerial particles latitant in the other parts of the water ( he had before spoken of the bottom of it ) may be extended into bubbles by his way of rarefaction . and that we particularly mentioned the rising of bubbles , even from the bottom of the water , was because that circumstance seem'd to deserve a peculiar note ; and not ( as he seems to imagine ) as if the bubbles did not also rise from the superior parts of the liquor , since we did take notice of it about the middle of the page . and we often in this and the following experiments observ'd , that the ascending bubbles grew bigger the nearer they came to the top . which agrees more clearly with our hypothesis , wherein their conspicuous swelling as they ascend is attributed more to the lessening of the pressure of the incumbent air then to the decrement of the weight of the incumbent water , ( since when the surface of this liquor is lean'd upon by the atmosphere , the ascending bubbles scarce sensibly increase in vessels no deeper then ours ) then with the explication which the examiner gives in these words , respondeo , aquam per illam aëris exhaustionem non sponte sic ascendere , sed sursum violenter trahi , ac elevari à rarefacto illo aëre sese contrahente . quemadmodum enim aqua aliqualem patitur compressionem ( ut experientiâ constat ) ita & aliqualem quoque hic patitur , distensionem . atque hinc clarè patet , cur potius à fundo vasis quam à parte aquae superiore oriantur hujusmodi bullae . cum enim vehemens illa suctio conetur aquam à fundo phialae elevare , nascitur ibidem subtilis quaedam materia quae in bullas conversa sic ascendit , uti capite decimo quinto in quarto experimento dictum est . for , whatever he may think , it does not hence so clearly appear how the endeavour onely of the funiculus to draw up the water from the bottom of the vial , to which , that endeavour notwithstanding , it remains contiguous , should generate in some parts of the bottom of the glass , and not in others , such a subtil matter as he tells us of . and i suppose the reader will , as well as i , wish he had more intelligibly declared how this strange generation of subtil matter comes to be effected . and i presume it will likewise be exected that he also declare , why both in our case and in the torricellian experiment the bubbles grow so much larger by being nearer the top of the liquor ; if , as he rejects our explication of this circumstance , the effect of the fuction he speaks of be greater upon the lower part of the liquor then the upper , to which alone nevertheless his funiculus , that is said so to draw the liquor , is contiguous . our author making no particular objection against the . following experiments , we also shall pass them by , and fall with him upon the consideration of the . experiment . the . experiment . upon this our author having recited our conjecture at the cause why two very flat and smooth marbles stick so closely together , that by lifting up the uppermost you may take up also the lowermost , approves my way of examining that conjecture . but whereas i say that the reason why , though the marbles were kept together by the pressure of the ambient air , yet they did not fall asunder in our exhausted receiver , no not though a weight of . ounces were hung at the lower stone , might be , that by reason of some small leak in the receiver the air could not be sufficiently drawn out : yet he tells us with his wonted confidence , certum esse , sententiam illam vel hoc solo experimento satis refelli . but possibly he would have spoken less resolutely , if he had made all the tryals about the adhesion of marbles that we relate our selves to have made in the short history we have publish'd of fluidity and firmness . for our examiner speaks as if all that we ascribe to the air in such experiments were to sustain the lower marble with the weight perhaps of a few ounces : whereas in case the air be kept from getting in at all between the stones , it may ( according to our hypothesis ) sustain a weight either altogether or well-nigh equal to that of a pillar of air as broad as the basis of the lower marble , and as long as the atmosphere is high , or to the weight of a pillar of quicksilver of the same thickness , and about . inches long ; these two pillars appearing by the torricellian experiment to counterpoise each other . and therefore since in the seventeenth experiment , when we had exhausted our receiver as far as we could , there remain'd air enough to keep up in the tube a cylinder of about an inch long of quicksilver ; and since the broader the contiguous marbles are , the greater weight fastned to the lowermost may be sustain'd by the resistance of the air , ( as is obvious to him that considers the hypothesis , and as we have proved by experiment in the forementioned tract ) it need be no wonder that the air remaining in the receiver should be able to support the lowermost marble , whose diameter was near two inches , and a weight of four ounces , those two weights being inferior to that of a mercurial cylinder of that diameter and an inch in length . and though it were not , yet we are not sure that the receiver was as well emptied when we made the . experiment , as when we made the . and ( if my memory does not much mis-informe me ) 't was with the same pair of marbles that in the presence of an illustrious assembly of virtuosi ( who were spectators of the experiment ) the uppermost marble drew up the lowermost , though that were clog'd with a weight of above . ounces . as for the account the examiner substitutes of our phaenomenon , i know not whether many readers will acquiesce in it : for , not to insist upon the objection which himself takes notice of , that according to him the distended air in the receiver should draw asunder the adhering marbles ; his explication supposes that there cannot naturally be a vacuum , whence he infers that , necesse er at ut lapis ille non aliter descenderet , quàm relinquendo post se tenuem hujusmodi substantiam , qualis ab argento vivo aut aquâ sic descendentibus relinqui solet . but whereas he adds , that the cause of the obstinate adhesion we meet with in our case is , that such a substance is far more difficult to be separated from marble then from quicksilver or any other kind of body ; that assertion is precarious . and though i have tryed experiments of this nature with stones of several sizes , perhaps an hundred times , yet i never could find that by their cohesion they would sustain a weight greater then that of a pillar of the atmosphere that prest against the lowermost : which is a considerable circumstance , that much better agrees with our explication then our adversaries . and whereas he further sayes , unde existimo planè , si perfectè complanata fuerint duo marmora sic conjuncta , it a ut nullus omnino aër inter utrumque mediaret , non posse ea ullis humanis viribus ab invicem divelli : i hope i need not tell the reader , that whether or no this agree with what he had immediately before taught of the separableness of a subtil substance even from marble , so bold and improbable an assertion requires the being countenanc'd with a much better proof then the onely one he subjoyns in these words , uti etiam confirmat exemplum quod ibidem adducit author de lamina aenea , tabulae cuidam marmoreae ita adhaerente , ut à lacertoso juvene , de suis viribus gloriante , non potuerit per annulum centro ejus affixum inde elevari . for sure there is great odds betwixt the strength of a man unassisted by any engine , and the ut most extent of humane power . and indeed according to our hypothesis , and without having recourse to natures dreading of a vacuum , the case is clear enough : for , supposing the plate to be of any considerable breadth , the pillar of the atmosphere that lean'd upon it , and must at the instant of its deserting the superficies of the table all at once be lifted up with it , may well exceed the force of a single man , especially in an inconvenient posture ; since by the cohesion of a pair of marbles of about three inches diameter , i did with my own hands take up above a thousand and three hundred ounces . the , and . experiments . against our explication of these two , which our author examines together , he objects nothing peculiar , but contents himself to explicate them by his funiculus : wherefore neither shall we need to frame any peculiar defence for it , especially if the reader will be pleased to refer hither as much of what we oppos'd to his animadversion on the third experiment as is justly applicable to our present controversie . our author indeed endeavours to prove his explication by saying , that the distended air in the exhausted cylinder draws up the sucker with the annexed weight , eodem fere modo quo videmus in cucurbitulis dorso aegrotantis applicatis , in quibus , extincta jam flamma , rarefactus aër se contrahens carnem tam vehementer , uti videmus , elevat attrahitque intra cucurbitulam . but that phaenomenon is easily enough explicable in our hypothesis , by saying , that upon the vanishing of that heat which strengthned the pressure of the included air , the spring of it grows too weak to resist any longer the pressure of the ambient air ; which thereupon thrusts the flesh and neighbouring bloud of the patient into the cupping-glass , almost after the same manner as we formerly taught the pulp of the finger to be thrust into the deserted cavity of the glass-tube in the torricellian experiment . the , , and . experiments . to these our author saying nothing but this , in his tribus nihil peculiariter occurrit hic explicandum , cujus ratio ex jam dictis non facile pateat ; we also may be allow'd to pretermit them , and pass on to the . experiment . of the appearance of light or whiteness , mentioned in this experiment , the examiner confesses that we have assigned a cause probable enough , by referring it to the vehement and sudden commotion of the included air. and indeed though i do still look upon some of the things that i hesitantly propos'd about this difficult phaenomenon but as meer conjectures , and though he annexes his explication of it ; yet i see not but that it is coincident with ours , or not better then it . for , to what i had said of the commotion of the parts of the air , he adds onely in two or three several places their being violently distended ; which how it improves the explication of the phaenomenon i do not readily see . and whereas he subjoyns , existimo autem dicendum potius candorem illum esse lumen quoddam reflexum , quam innatum , eo quod ( ut testatur author ) in tenebris non appareat , sed solum de die aut accensa candela : i presume the attentive reader will easily discern that his opinion is much-what the same that i propos'd and grounded on the same reason . but the chief difficulty in this abstruse phaenomenon , namely why we meet with it but sometimes , our examiner's explication leaves untouch'd . the . and . experiments . against these our author makes no peculiar objections . the . and . experiments . but in his animadversions upon these , having told the reader that i seem to ascribe the sudden extinction of the included animals to the excessive thinness of the air remaining in the receiver , made by the recess of what was drawn out , unfit for respiration ; he adds resolutely enough , verum impossibile videtur , ut hujusmodi animalcula ob solum defectum crassioris aëris tam cito moriantur : but gives no other reason then that they dye so soon , which is no more then what he said in the newly-cited words , and besides is grounded upon something of mistake . for the creatures he mentions were a bee , a flye , and a caterpillar , and those included too in a small receiver , which could be suddenly exhausted : and these indeed became moveless within a minute of an hour ; but that minute was not ( as the word is often us'd to signifie in english ) a moment , but the sixtieth part of an hour . and though these insects did in so short a time grow moveless , yet they were not so soon kill'd ; as appears by the narrative . the sanguineous animals that did indeed dye , were kill'd more slowly . and i remember that having purposely enquir'd of a man ( us'd to go under water by the help of an engine wherein he could carry air with him to the bottom of the sea ) how long he could endure , before he was accustomed to dive , without breathing or the use of a spunge ; he told me , that at first he could hold out about two or three minutes at a time : which made me think that divers become able to continue under water so long , either by a peculiarly-convenient constitution of body , or by a gradual exercise . and i am apt to think that he did , as men are wont to do , when he said two or three minutes , mean what is indeed a much shorter time then that when exactly measured amounts to . for , having purposely made tryal upon a couple of moles that were brought me together alive , one of them included in a small , though not very small , receiver was between two and three minutes in killing ; whereas the other being immediately after detain'd under water did not there continue full a minute and a quarter , before it finally ceas'd from giving any sign at all of life . by which tryal it may appear , that 't is not impossible that the want of respiration should dispatch an animal in as little time as is mentioned in the experiment i am now defending . and indeed our author either should have proved that 't is not possible for the want of air to destroy animals so soon , or should have given us some better account of the phaenomenon . for whereas he teaches us , that according to his doctrine the little animals above-mentioned were so soon kill'd , qui a per rarefactum illum aërem sese contrahentem extractus sit eorum halitus : i see not that hereby , if he explicate the phaenomenon otherwise then we , he explains it better ; for he seems to speak as if he thought this halitus to be some peculiar part of the animal in which his life resides . and besides he seems not to consider , that whereas , according to me as well as according to him , the air contained in the lungs ( supposing these animalcula have any ) must in great part pass thence into the receiver , ( for whether that be done by the spring of the air it self , that was harboured in the lungs , or the traction on of the more rarefi'd air in the receiver , is not material in our present case ) the examiner must , as well as i , render a reason why the extenuation or recess of the halitus should cause the hasty death of the included animals ; and condemning my conjecture he ought to have substituted another reason : and though he subjoyns these words , and concludes with them , atque hinc quoque ortae sunt vehementes illae convulsiones , quas ante mortem passas esse aviculas quasdam memorat ibidem author ; yet i doubt not but the reader will think it had not been amiss that the author had more intelligibly deduc'd these tragick symptoms from his assumption , for the sake of those that are not anatomists and physicians enough to discern how his funiculus could produce these effects . for my part , as in the . experiment i tender'd my thoughts concerning respiration but doubtingly , so i am yet unwilling to determine resolvedly in a matter of that difficulty . the , and . experiments . in his examen of these two last of our physico-mechanical experiments , the author contents himself to endeavour to explicate the phaenomena recited in them by the contraction of the rarefi'd air ; which , according to him , endeavours to draw up the subjacent water out of the vial , whereby it vehemently distends the parts of that water , as he taught in the like case upon the . experiment . but since we have already consider'd his animadversion upon that , although this presumed distension of the water is not visible that we have observ'd , when cold water , that has been first freed from his interspers'd air , is put into the receiver , notwithstanding that the funiculus should in that case also distend it ; we are so afraid of tiring out the readers patience by the frequent repetition of the same things , that we will leave it to him to judge which of the two explications , the examiner's or ours , is to be preferred , without troubling him and our selves with defence of accounts against which our adversary does not here make any peculiar objections . and thus have we by gods assistance considered what the exam ner hath been pleased to oppose either against our particular explications , or against the hypotheses that divers of them suppose : wherein i have been the more particular and prolix , because i would willingly excuse my self and others from the trouble of any more disputes of this kind . i hope there is not in my answers any thing of asperity to be met with ; for i have no quarrel to the person of the author , or his just reputation ; nor did i intend to use any more freedom of speech in the answering his objections , then his resolute way of proposing divers of them made it on those occasions needful for the caution of those readers who are not acquainted with our differing wayes of writing , and perhaps have not observed that some men are wont to consider as much what they propose but with a perhaps , or some such expression of diffidence , as others do what they deliver far more resolutely . and though being very far from being wedded to my opinions , i am still ready to exchange them for better , if they shall be duly made out to me , ( which i think it possible enough they may hereafter be ; ) yet peradventure the reader will think with me , that the examiner has not given me cause to renounce any of them , since the objections he has propos'd against me have been sufficiently answered , and since the hypothesis he would substitute in the room of ours ( besides that it is partly precarious ) supposes things which divers of the eminentest wits of our age ( otherwise of differing opinions ) profess they cannot admit or so much as understand : whereas the weight and spring of the air are not denyed by our author himself , and are demonstrable by experiments that are not controverted betwixt us . which things i represent for the defence of what i think the truth , and not to offend my learned adversary , who shall have my free consent to be thought to have fail'd rather in the choice then in the management of the controversie . though since this passes for his first book , and since consequently he is not like to have been provoked , or engaged in point of reputation , to challenge me or any of those far more eminent persons he has nam'd among his adversaries , i am induc'd by the severity wherewith i have known eminent virtuosi speak of his attempts , and particularly of his funiculus , to fear that some of those he has needlesly oppos'd , will be apt to apply to him that of st. austin against some of his adversaries , that had disputed against him with much more subtilty then reason , in mala causa non possunt aliter , at malam causam quis eos coegit habere ? but this notwithstanding i am , as i was going to say , content my adversary should be thought to have said for his principles as much as the subject will bear ; nor would i have it made his disparagement , that i have declared that his whole book has not made me depart from any of my opinions or explications , since his hypothesis and mine being inconsistent , it may be looked upon as a sign rather that each of us have , then that either of us have not , reason'd closely to his own principles , that the things we infer from our contrary suppositions do so generally disagree . finis . an explication of rarefaction . the chief arguments of the author of a certain treatise de corporum inseparabilitate , whereby he endeavours to invalidate the hypothesis of the weight and spring of the air , and to set up and establish instead thereof an unintelligible hypothesis of attraction , performed by i know not what strange imaginary funiculus , are onely five , two against the former , and three for the later . the first of which is , that the weight and spring of the air are not sufficient to perform the effects ascribed to them : the second , that could they be performed by that hypothesis granted , yet the way of this strange spring it self is not intelligibly explained or explicable by the defenders of it . now the former of these being little else but a bare affirmation , and the later bearing some shew of demonstration , i shall endeavour to examine it as i find it set down in his , , , , and . chapters , to which ( especially the . ) he very often in his book refers the reader for satisfaction , pretending there to evince that rarefaction cannot be made out any otherwise then by supposing a body to be in , , , , , , of places at the same instant , and adequately to fill all and every one of those places . first therefore , we will examine his negative , and next his affirmative , arguments for this strange hypothesis . his negative i find in the . chapter , where he endeavours to confute the two wayes of explicating the rarefaction and spring of the air , namely , that of the vacuists and that of the plenists . concerning the first of these we find him conclude it impossible , first , because he had before proved that there can be no vacuum , which being done by a circle ( viz. there is no vacuum in the tube because nature abhors a vacuum , and we see nature abhors a vacuum because she will not suffer a vacuum in the tube above the mercury , but to prevent it will continually spin the quicksilver into supe ficies , and never diminish the body of it ) will suffer me to pass to his next , which is , that this way is false , because in the experiment of the carps bladder the air is rarefi'd a . times bigger ; nay , in respect of the body of gold it has . times less matter in equal spaces . and this , sayes he , is a phaenomenon that is impossible ever to be made out by interspers'd vacuities . now that the vacuists cannot presently , by so bold an assertion as this , be made to forsake their principles , he may perceive by these following solutions which i shall give of all the phaenomena he recites , flowing naturally from an hypothesis that i shall for the present assume . let us suppose then the particles of bodies , at least those of the air , to be of the form of a piece of riband , that is , to be very long , slender , thin and flexible laminae , coyled or wound up together as a cable , piece of riband , spring of a watch , hoop , or the like , are : we will suppose these to have all of them the same length , but some to have a stronger , others a weaker spring : we will further suppose each of these so coyled up to have such an innate circular motion , as that thereby they may describe a sphere equal in diameter to their own , much after the manner that a meridian turn'd about the poles of a globe will describe by its revolution a sphere of the same diameter with its own in the air. by this circular motion the parts of the laminae endeavouring to recede from the centre or axis of their motion , acquire a springiness outward like that of a watch-spring , and would naturally flye abroad untill they were stretch'd out at length , but that being incompast with the like on every side , they cannot do it without the removal of them , as not having room sufficient for such a motion . and the faster this circular motion is , the more do the parts endeavour to recede from the axis , and consequently the stronger is their spring or endeavour outward . these springy bodies thus shap'd and thus moved are sufficient to produce all the phaenomena he names as impossible to be explicated . and , first , for the business of expansion , it will very naturally be explained by it : as let us suppose for instance the diameter of these small coyled particles of the air ( which being next the earth are press'd upon by all those numerous incumbent particles that make up the atmosphere , and are thereby so crouded that they can but very little untwist themselves ; let us suppose , i say , the diameter of these particles ) to be / of an inch ; and then to be much of the form of those represented in the . figure by a b c d : and that these particles , when a considerable quantity of the pressure of the ambient parts is taken away , will flye abroad into a coyle or zone ten times as big in diameter as before ; that is , they will now be / of an inch in diameter , and appear in the form of those in the figure exprest by e f g h : these zones whirl'd round as the former will describe a sphere a . times as big in bulk , and thereby fence that space from being entred by any of the like zones : this it would do , supposing those spheres did immediately alwayes touch each other ; but because of their circular motion , whenever they meet they must necessarily be beaten , and flye off from one another , and so require a yet greater space to perform their motion in . this suppos'd , there are no phaenomena of rarefaction ( which is enough at present to answer what he objects ) but may be naturally and intelligibly made out . as first , for that of the swelling of a carps bladder , if we suppose some small parcels of the former comprest laminae to lye latitant within the folds of it , and being much coyled up together scarce to take any sensible room , this bladder in the air will appear to contain very little or nothing within it ; whereas when the pressure of the air is taken off in good part from the outsides of it , then those formerly latitant particles disclose themselves by flying open into much bigger zones , so as perhaps to be able to defend a thousand times bigger space from being entred into by their like or any other gross particles , such as those of the bladder . now because the pores of a bladder are such as are not easily permeable by the particles of air , therefore these lurking particles so expanding themselves must necessarily plump out the sides of the bladder , and so keep them turgid untill the pressure of the air that at first coyled them be re-admitted to do the same thing for them again . next , as for rarefaction by heat , that will as naturally follow as the former from this hypothesis . for the atoms of fire flowing in in great numbers , and passing through with a very rapid motion , must needs accelerate the motion of these particles , from which acceleration their spring or endeavour outward will be augmented , that is , those zones will have a strong nitency to flye wider open , ( for we know that the swifter any body is moved circularly , the more do the parts of it endeavour to recede from the centre of that motion ) from whence if it has room will follow a rarefaction . as for the conveyance of light , that being according to epicurus performed by the local motion of peculiar atoms , their motions to and fro through this medium will be less impeded by the rarefi'd air then by the condens'd ; as indeed upon experiment we shall really find them . as for his third objection drawn from his supposed attractive virtue of the thus rarefi'd air , that is quickly answered , by denying it to have any power at all of attraction ; and by shewing ( which is already done ) that what effects he would have to be performed by the attraction of the included , is really done by the pressure of the ambient , air. and , lastly , the phaenomena of my lord bacons experiment are sufficiently obvious and easie to be deduc'd . so then , by granting epicurus his principles , that the atoms or particles of bodies have an innate motion ; and granting our supposition of the determinate motion and figure of the aerial particles , all the phaenomena of rarefaction and condensation , of light , sound , heat , &c. will naturally and necessarily follow : and the authors objections against this first way of rarefaction will signifie very little . as to the second way of rarefaction , by the intrusion or intervention of some subtil matter of aether into the spaces deserted by the raresying particles , which is that propos'd by the assertors of a plenum , this also is by the author condemned , and branded with impossibility . and why ? first , because 't is ( he sayes ) impossible that the above-mentioned phaenomena of the carps bladder can be explained by it . secondly , because 't is impossible to give a reason from it of the impetuous ascent of water admitted into an exhausted receiver . and , thirdly , because 't is impossible to explicate the phaenomena of gun-powder . his reasons to confirm which three impossibilities , because drawn from a meer mistake , or ignorance of those hypotheses which have been invented by the assertors of that opinion , i shall pass over , and content my self to explain a way how these impossibilities may become possibilities , if not probabilities . and the way that i shall take , shall be that of the most acute modern philosopher monsieur des cartes , published in his philosophical works : which is this , that the air is a body consisting of long , slender , flexible particles , agitated or whirl'd round by the rapid motion of the globuli coelestes , and the subtile matter of his first element , whereby they are each of them enabled to drive or force out of their vortice all such other agitated particles . now the swifter these bodies are whirl'd round , the more do their flexible parts fly asunder and stretch themselves out ; and the more forcibly do they resist the ingresse of any other so agitated particles into their vortice , and consequently the slower their motion is , the less will be their resistance . and because there is a vast number of these whirled particles lying one above another , and each particle having its peculiar gravity ; it will necessarily follow that the undermost ( which to maintain their vortice must resist so great a pressure ) must very much be hindred from expanding themselves so far as otherwise they would , were there none of those incompassing agitated particles that lay in their way : and that those being by any means removed , or they themselves by a more rapid motion of the particles of their vehicles , the first and second element , ( which is according to that hypothesis an effect of heat ) more swiftly and strongly whirled round , they presently begin to expand themselves , and maintain a bigger vortice then before . now to perform what i just now promised , i shall endeavour to give a possible , if not a probable , cause of the objected phaenomena . and , first , for that of the carps bladder , where the air is rarefi'd ( sayes the author ) . times , it will easily be explained by supposing the few particles of the air , which ( whilest they sustain the pressure of all the incumbent atmosphere ) inconspicuously luck within the bladder , ( each of them being able to maintain but a very small vortice ) to be by the subsiding mercury in the torricellian experiment freed from the pressure of the air , and their motion continuing the same ( by reason that the transcursion of their vehicles is not at all or very little hindered either by the glass or bladder ) their parts having room to expand themselves , will flye abroad to such extensions as may perhaps make a vortice . times as big in bulk as what they were not able just before to exceed . hence the particles of the air ( being so gross as not easily to pervade the pores of the bladder ) must necessarily drive out the fides of the bladder to its utmost extent , and serve to fill the receiver in the magdeburgick experiment . now , whereas these particles will by the same pressure of the air be reduc'd to the same state they were in at first , that is , to be thronged into a very little room , and thereby be able to maintain a very small vortice ; the air let in in the torrecellian experiment reduces the air in the bladder to its former inconspicuousness ; as the admission of the water in the magdeburg experiment does that receiver full of rarefi'd air into the bigness of a hazel nut. now the water in this last-mention'd experiment enters with a great impetuosity , because driven on with the whole pressure of the atmosphere , and resisted onely by the small force of the so-far-rarefi'd air. as for the authors objection against this way of rarefaction drawn from the phaenomena of gun powder , i shall endeavour to answer it by shewing them possibly explicable by a cartesian hypothesis . for supposing those terrestrial parts of the gun powder to be first at rest , and afterwards agitated by the rapid motion of his first element , there will be sufficient difference of the former and later condition in respect of extension ; and supposing the particular constitution of gun-powder ( arising partly from the specifick forms of the particles of its ingredients ; nitre , sulphure and char-coal , and partly from their proportionate commistion ) to be such as will readily yield to the motion of his materia subtilis , so soon as an ingress is admitted to it by the fireing of any particular parcel of it , the expansion will be speedy enough . so then let us suppose a barrel of gun-powder placed in some close room , to some grains of which we will suppose some actual fire to be applied , by which actual fire ( the texture of the powder being such ) those grains are suddenly fired , that is , many millions of parts , which before lay still and at rest , are by the action of the burning coals shatter'd , as it were , and put into a posture ready to be agitated by the rapid motion of the materia subtilis : into which posture they are no sooner put , then agitated and whirled sufficiently by it ; whence follows a vast expansion of that part of gun-powder so fired . for each of its parts being thus whirl'd and hurried round , expell and beat off with great violence all the contiguous particles , so as that each particle takes up now . times as much elbow-room ( if i may so speak ) as just before serv'd its turn , and consequently those that are outermost take every one their way directly from the parcel or corn they had lain quiet in , being hurried away by the sudden expansion of the particles that lay next within them ; so that whatever grain or parcel of gun-powder they chance to meet with , before they have lost their motion , they presently shiver and put into such a motion as makes them fit to receive the action of the materia subtilis . which subtil matter being every where present , and nothing slow in performing its office , immediately agitates those also like the former ; so that in a trice the particles of the whole barrel of gun-powder are thus disordered , and by the motion the materia subtilis must needs be hurried away with so great an impetuosity on all sides , as not onely to break in pieces its slight wooden prison , and remove the lighter particles of the ambient air , but huge beams , nay , vast accumulated masses of the most compacted structures of stone , and even shake the very earth it self , or whatever else stands in its way , whose texture is so close as not to give its particles free passage through its pores . this understood , i see not , first , what the authors three arguments brought to prove his objection signifie , for there are no more corpuscles in the room before the gun-powder is fired then after , nor is there any more matter or substance before the sides of the room by yielding give place for the external fluid bodies to succeed , and the onely change is this , that the globuli secundi elementi ( as he calls them ) are expell'd out of the room , and the materia primi elementi succeeds in the place of it . nor do i see , secondly , what great reason he had for his grand conclusion , haec abundè demonstrant , rarefactionem per hujusmodi corpuscula nullatenus posse explicari . having thus examined the authors first arguments , that rarefaction cannot be made out by any other way then his ; we shall find his other , which he brings to establish his own hypothesis , much of the same kind . as , first , that his way of rarefaction implies no contradiction : for if the affirming a body to be really and totally in this place , and at the same time to be really and wholly in another , that is , to be in this place , and not to be in this place , be not a contradiction , i know not what is . next , that some learned school-men have thought so ; to which i answer , more learned men have thought otherwise . and , lastly , that there are very plain examples of the like nature to be found in other things ; of which he onely brings one , viz. that of the rota aristotelica , which upon examination we shall find to make as little to the purpose as any of the other . an explication of the rota aristotelica . the great problem of the rota aristotelica , by his explication of which he pretends not onely to solve all the difficulties concerning local motion , quae philosophorū ingenia hactenus valde exercuerant , but to give an instance for the confirmation of his unintelligible hypothesis of rarefaction , wherein there is extensio seu correspondentia ejusdem rei ad locum nunc majorem , nunc minorem ; we may upon examination find to be either a paralogisme , or else nothing but what those philosophers said whom he accounts gravel'd with it . of this subject he begins in his . chapter , where after he has set down a description of it , he makes an instance in a cart-wheel ; rem ante oculos ponit rota alicujus currus , ejusque umbo seu lignum illud crassum & rotundum cui infiguntur radii ; siquidem dum progrediente curru ipsa rota circumducta describit in subjecta terra orbitam sibi aequalem , umbo ille describit in subjecto aëre orbitam . ( i suppose both here and before he means lineam ) se multo longiorem , utpote aequalem orbitae totius rotae , licet ipse non nisi semel quoque fuerit circumvolutus . ( as for what he sayes , that the nave must be suppos'd to pass through the air , and not to touch a solid plain , i do not yet understand the force of his reason , nor why he sets it down , making nothing to his present purpose , unless it were because he did not well understand the thing ) in which , sayes he , the great difficulty is to explain how the nave should be so turned about its axis , ut partes suas successivè applicet lineae duplo plures partes habenti , idque motu perpetuo ac uniformi nè vel ad oculum instar interrupto . which how true , and what great occasion he had to wonder at the solution of that problem by the example of a man standing still and another walking , we shall find by and by , when we come to explain the problem : but first i shall examine his hypoth sis and explication . and first , he supposes time to consist of a determinate number of indivisibles , ( that is , such as have neither prius nor posterius included in them ) which he calls instants . and next he supposes the praesentiam localem seu ubicationem cujuslibet part is indivisibilis & virtualiter extensae esse quoque indivisibilem & virtualiter extensam : which supposition so strangely exprest is no more then this , that the extension or space of his indivisibles is also indivisible . but as for his virtual extension , i consess i understand as little what it is as i verily believe he did ; and therefore i will proceed to his following supposition . his third therefore is , that by how much more rare a body is , by so much the more are its indivisibles virtually extended . hence his fourth is , that though these indivisibles be really indivisible , yet they are virtually in quotvis partes divisibiles . whence he deduces his fifth principle , that since these indivisibles are really indivisible and virtually extended , they must necessarily be moved after the same manner that other indivisible and virtually-extended things are . his instances are in the motions of an angel and an indivisible piece of wood , which , he sayes , are both of the same kind . as for that of angels , having no immediate revelation , and a spirit and its actions not falling under sense , and not having any third way by which to be inform'd , i shall leave him there to enjoy his fancies . but as for that of his piece of wood , we shall find it sufficiently full of absurdities and contradictions . and first , he calls it indivisible , but why i know not , for 't is neither really nor yet mentally so : not mentally so by his fourth principle , where he sayes that 't is virtualiter in quotvis partes divisibiles , by which word virtualiter he means the same thing with mentaliter , or nothing . nor , secondly , is it really so : for then ( according to the main business of his book , as may be gathered from the first words of his title-page , tractatus de corporum inseparabilitate ) it would be impossible that any thing in the world should be divisible ; for he making an inseparable continuity , and that bodies will rather be ( i can't tell how ) stretcht beyond their own dimension in infinitum , then part from one another ; a body may as soon pass through the dimensions of any one indivisible , as pass between two . next , he grants in the strange stretching or rarefaction of these indivisibles a temporary motion of the condens'd dimension ; whence there will follow that there must be distinct places or ubi's , it must be terminus à quo , terminus ad quem , & medium . and next , it were impossible to divide a line into two parts , supposing it consisted of an unequal number of indivisibles ; as if . indivisibles of exceedingly-rarefi'd air should be extended in length an inch , it were impossible to divide that inch into two equal parts . i might run over many more , but it would be too tedious to be here recited . as for his indivisible parts of time , those also must necessarily be in quotvis partes divisibiles ; for else the same body or indivisible must necessarily be in divers places at the same instant . but because he can swallow , nay confidently affirm , this and many other such like contradictions and absurdities , i am not willing to mention them ; and i think it would have made more for the authors reputation if he had done so too . as for his last chapter , where he applies these principles to the explication of the rota aristotelica , i have not here time to set down all the absurdities that any one that has but a smattering in the mathematicks may observe : as , sometimes half an indivisible part of a circumference may touch an indivisible of a line ; sometimes one may touch half , a quarter , a hundredth part , a whole one , two , ten , a hundred , &c. at the same instant ; nay , an indivisible of a circle may be all of it in a thousand places together , and the like . and this he brings as a great argument to establish his hypothesis of rarefaction , pretending it to comprise many aenigma's and very great difficulties ; whereas the thing is very plain and easie , and contains no such obscurities . for if , for example , we suppose a wheel abcd to be moved in a direct motion from aic to klm , every point of it retaining the same position to that line that they had at the beginning of their motion , each of the points aeigc will on a plain , or in the medium it pervades , pass through or describe a line equal to the line il , and not onely all the points lying in the line aic , but all and every point of the whole area of the circle ; this must necessarily happen if the diameter aic be moved parallel to it self : but if whilest it be thus moved with an equal progression , it be likewise moved with an equal circulation , the case will be altered . for then , first , each point will by this compound motion describe on the plain or medium either a perfect cyclorid , as when the wheel makes one perfect revolution , whilest the whole is progressively moved from i to l ; or some piece , as when the wheel has not perfected its revolution ; or more then a whole one , as when the circle has made more then one whole revolution whilest it is moved in its determinate length . i shall here onely consider the first , as pertaining more especially to my present purpose , and in regard the two later on occasion may be easily explicated by it . next , each point of this circle acquires from its compounded motion various degrees of celerity as to its progression , according to its various position to a point which is alwayes found in some part of the line drawn through the centre of the circular motion perpendicular to the progressive . and it is found thus , as the circumference to the radius , so is the line of the progressive motion to the distance of the point from the centre . and this happens because the line of progression is equal to the circle described on that distance as radius ; each point therefore of this smaller circle , when it comes to touch the perpendicular , must , as to its progressive motion , stand still : this point therefore will be the centre of this compounded motion . now because for the explication of the rota aristotelica we need not consider any other then those points which are transient through or cross the perpendicular line , we shall onely examine them . let then in our example a be the centre or immoveable point , the circumference therefore abcd will be equal to il or ak by our hypothesis . now because the point i , which is the centre of the rotation , has onely one motion , viz. that of lation , its celerity will be equal to the single celerity of the lation ; we will therefore put it to have one degree . c , because it is moved with two motions , both tending the same way , and each equal to the velocity of i , must needs have two degrees of velocity . the point f , because moved with two motions , both tending the same way , the one ( viz. its lation ) being equal to that of i , and the other ( because it is but half as far distant from the centre of rotation as c , and therefore is moved but with half the celerity of c , which was equal to that of i ) but half as quick , we will put to have one degree and an half . by the like method we might find the velocity of all the points in the perpendicular , viz. such as we have there marked some of them ; but it would be too tedious , we needing not to consider more then the two points a and e. the point at e being moved forward by its progression with the same velocity that i , but by its rotation ( which is but half as swift as that of the circle abcd , that is double the circle efgh ) being moved the contrary way or backwards with half the velocity , loseth half of its progression forwards . the point in a being by its progression moved forwards equally swift with i , and by its rotation ( the circle abcd being equal to the line il ) being carried backwards with equal velocity , must necessarily stand still as to its progression . now having shewn that the point a ( being by reason of its two equal opposite motions at rest ) does onely touch a point of the line ak , and is not at all moved on it ; and that the point e ( being carried forward twice as fast by its progression as it is carried backward by its rotation , and thereby moved half as fast as the point i ) does not onely touch the line ek , but whilest it touches it is moved on it with a progressive motion half as swift as that of i : it will necessarily follow , that each point situate in e must necessarily describe a small line , which is a part of the whole ec . now both the contact of the former , and the contact and progression of the later , being performed by an infinite succession of points in the space of an infinite succession of instants ; i see not any one difficulty of this problem but may satisfactorily be given an account of by it , without having recourse to the hypothesis of the determinate number of indivisibles of space and time ; which at best will onely come to this , that in such a determinate moment or minute space of time , ( which consists of an infinite consecution of instants , and has prius and posterius in it ; though yet he will call it an instant , and have it to have the same proprieties with an instant used in the common philosophical sense ) such a determinate minute corpuscle ( which , though it have extension in length , breadth and thickness , yet will he not admit it to be divisible or have parts , no not though , according to his hypothesis , the indivisible of one body may be rarefied to be as big in bulk as a million of the indivisibles of another , but will have it to be called and to be a real indivisible ) will successively pass over such a determinate space or length ( which yet he will not admit to be divisible , though according to his principles it may equalize the length of millions of his other indivisibles , nor admit a successive motion , but instantaneous , though that does necessarily put a body into two , three , ten , a hundred , &c. places at once ; but will have these also to be indivisible . ) haste makes me pass over the absurdities about the contact of a circle and a line , and to comprise in short all that great explication he has given of this and other intricate ( as he calls them ) problems , which is this , that the reason of the celerity of the motion of some one of these indivisibles above another is , that it passes through a greater part of an indivisible in the same instant then the slower ; that is in plain sense no more then this , one body is swifter then another because it is moved faster , from whence he draws several corollaries , as that hence may be given a reason why an eagle is swifter then a tortoise , viz. because it moves faster . i should have solved several objections which may be brought against the divisibility of quantity in infinitum ; but that as all the scholastick writers are full of them , so it is a subject which we are least able to dispute of , having very little information of the nature of infinity from the senses . finis . the citations english'd . chap. . pag. . cum tota vis , &c. being the whole power of the spring of the air depends upon the aequilibrium of its weight with twenty nine inches and an half of quicksilver , so that this spring doth neither more nor less in a shut place , then is done by that aequilibrium in an open place : it is manifest , seeing we have shewed the aequilibrium to be plainly fictitious and imaginary , that the spring ascribed to the air is so likewise . ibid. nam si tubus , &c. for if a tube but twenty inches long ( such as we used in our first argument ) be not quite filled with quicksilver , as before , but a little space be left betwixt the mercury and the finger on the top of the tube , in which air onely may abide : we shall find that the finger below being removed , the finger on the top will not onely be drawn downwards , as before , but the quicksilver shall descend also , and that notably , viz. as much as so small a parcel of air can be extended by such a descending weight . so that if instead of air , water or any other liquor which is not so easily extended be put in its place , there will be no descent at all . hence , i say , against this opinion an argument is framed : for if the external air cannot keep up those twenty inches of quicksilver from descending , as we have proved ; how shall it keep up twenty nine inches and an half ? assuredly these can no way be reconciled . p. . dices fortè , &c. you will perchance say , that the quicksilver therefore doth in the alledged case descend , because it is thrust down by that parcel of air which dilates it self by its own spring . ibid. sic deberet , &c. so should the finger be rather thrust from the top of the tube , then thereby fastned to it ; because this dilatation must be made as well upwards as downwards . p. . concipi , &c. it cannot be conceived how that air should dilate it self , or thrust down the mercury , unless by taking up a greater place ; which thing these authors are much against , asserting that rarefaction can be made no other wayes then by corpuscles or vacuities . chap. . p. . si , &c. if you take a tube open at both ends of a good length , suppose forty inches long , and fill it with mercury , and place your finger on the top as before , taking away your lower finger you will find the mercury to descend even to its wonted station , and your finger on the top to be strongly drawn within the tube , and to stick close unto it . whence again it is evidently concluded that the mercury placed in its own station is not there upheld by the external air , but suspended by a certain internal cord , whose upper end being fastned to the finger draws and fastens it after this manner into the tube . chap. . p. , . sumatur , &c. take a tube shorter then twenty nine inches and an half , for instance of twenty digits , not shut , as hitherto , at one end , but with both ends open : let this tube , its orifice being immers'd in restagnant mercury , and one finger being plac'd underneath , that the mercury to be poured in run not through , be filled with mercury ; and then another finger be applied to its orifice , to close it well : which being done , if you draw away your lower finger , the upper will be found to be strongly drawn and suck'd into the tube , and so stifly to adhere to it , ( or rather to the quicksilver , as i shall hereafter shew ) that it will elevate the tube it self with all the quicksilver , and make it continue to hang pendulous in the vessel . from which experiment this opinion is most clearly refuted : for , seeing according to it the quicksilver in such a tube but twenty inches long must be thrust upwards by the preponderating air ; it will never by it be explained how this finger is so drawn downwards , and made so strongly to stick to the tube . for it cannot by the air thrusting upwards be thus drawn downwards . p. . quod vel , &c. which is thence confirmed , because if that preponderating air succeeds , as is asserted , in the place of the lower finger which was withdrawn , that is , if it uphold the quicksilver after the same manner which it was upheld by the lower finger applied under it ; it is manifest , according to this opinion , that the finger on the top ought not to be more drawn downwards after the lower finger is removed then before . seeing then that experience teacheth the contrary , it is manifest that opinion must be false . chap. . p. . quarto , &c. in the fourth place it is impugn'd , because thence it would follow that quicksilver through a like tube might be suck'd with the same easiness out of a vessel that water is suck'd out of the same . which not withstanding is contrary to experience , by which we are taught that water is easily drawn into the mouth of him that sucks , whereas quicksilver cannot be drawn thither by his utmost endeavour , nay , scarce unto the middle of the tube . the sequel i thus manifest : because seeing , according to this opinion , that the liquor underneath , whether it be water or mercury , may so ascend , no more is requir'd but that the air shut in the tube may be drawn upwards by sucking ; which being drawn up , the liquor underneath will immediately ascend , being thrust thither by the external air now preponderating , ( as pecquet declares in his anatomical discourse , p. . ) it is manifest that the mercury may be suck'd out with the same easiness that water is suck'd out with . which being so evidently against experience , the opinion from whence it is deduced must needs be false . p. . neque hoc , &c. and not onely this , but over and above , if a glass diabetes or syringe be made of a sufficient length , and after that the sucker is thrust into the utmost orifice , it be placed according to use in the mercury underneath ; he finds that as soon as the sucker is drawn out , the mercury follows , and ascends to the same height of two feet and three inches and an half . and when afterwards , although no greater force be added , the sucker is drawn higher , he finds that the mercury stands , and follows no further , and so that space is made empty which remains between the mercury and the sucker . p. . maneat igitur , &c. be it therefore confirm'd by so many arguments , of which every one is sufficient in it self , that quicksilver ( the experiment being made in an open place ) is not upheld from falling by the weight of the external air. cap. . p. . argentum , &c. that quicksilver in a close place is not upheld from falling by the elater or spring of the air. ibid. cum tota , &c. seeing the whole power of this spring depends upon the already-confured aequilibrium of the air with . inches and an half of quicksilver , so that this spring does neither more nor less in a close place then is done by that aequilibrium in an open place ; it is manifest , seeing this aequilibrium is already shewn to be plainly fictitious and imaginary , that the spring of the air is so likewise . ibid. nec plus , &c. and that this spring doth neither more nor less in a close place , then is done by that aequilibrium in an open place . p. . adde , &c. adde , that seeing the experiments brought in the chapter above of the adhesion of the finger , &c. are alike in a close and an open place ; it is necessary and certain that the same arguments made against the aequilibrium have force against the spring of the air. ibid. et profecto , &c. and really if these authors would consider how great a difficulty there is in explaining this spring of the air , unles ; the same air by it self alone may take up a greater place , i believe they would readily alter their opinion . part . chap. . p. . constat hoc , &c. this appears from what has been already spoken in the preceding chapter : for the quicksilver descending cannot so draw the finger downwards , and fasten it unto the tube , unless it be hung upon the finger by such a cord , which by its weight it vehemently stretches , as is manifest by it self . ibid. respondeo , &c. i answer , that this comes to pass that there may be no vacuity , seeing there is nothing else there that can succeed into the place of the descending quicksilver . p. . and hence is confirm'd that common axiom used in the schools for so many ages past , that nature doth abhor a vacuum . ibid. nam licet , &c. for though the immediate cause why water ( for instance ) doth not descend from a gardeners watering-pot ( for that example they use ) stopt on the top , is not the fear of a vacuum , but the reason now mentioned , namely , that there is not weight sufficient to loose that conjuncture by which the water doth adhere to the top of the closed water-pot : nevertheless in the end we must of necessity come to that cause . ibid. quae quidem , &c. which traction and adhesion when it cannot proceed but from some real body placed between the finger and the mercury , it is manifest that that space is not empty , but filled with some true substance . ibid. eo quod , &c. because no visual species's could proceed either from it , or through it , unto the eye . p. . vera , &c. to be filled with any true substance . p. . huc etiam , &c. and to this purpose make those considerable vibrations with which quicksilver is stirred in its descent : for the same thing happens here that befalls other pendula in their fall from on high . p. . argentum dum , &c. quicksilver while it fills the whole tube doth not onely touch its top , ( as you would think at the first sight ) but doth firmly stick unto it also ; as it is manifest from the experiment mentioned in the first argument of the third chapter , concerning the tube open at both ends . ibid. licet illud , &c. though that orifice of the tube be anointed with oyle , or any other matter that will hinder adhesion , nevertheless the finger will no less firmly stick then before . ibid. partes , &c. that the parts of air it self so shut up in the tube ( which otherwise are so easily severed ) are now so firmly glued to one another , that they make ( as we see ) a strong chain , by which not onely water but even weighty quicksilver is drawn on high . ibid. rarefactionem , &c. that the rarefaction or extension of a body so as to make it take up more space is not onely made by heat , but by distension or a certain disjoyning power ; as on the contrary condensation is not onely made by cold , but also by compression , as infinite examples hear us witness . p. . cum per , &c. seeing by the first note 't is manifest that the quicksilver doth so stick to the top of the tube , and by the second note the rarefaction is made onely by the meer distension of the body ; it so comes to pass that the descending quicksilver leaves its external or upper superficies fixed unto the top of the tube , and by its weight doth so stretch and extenuate it , untill it becomes easier to leave another superficies in like manner , then to extend that any further . it leaves therefore a second , and doth by its descent extend that a little further , untill it becomes easier to separate a third then to extend that any further : and so forwards , untill at length it hath no power to separate or extend any more superficies , namely , untill it comes unto the heighth of . inches and an half ; where it acquiesces , as we have declared in the first chapter . p. . these surfaces seem to be separated from the quicksilver , and to be extended into a most slender string by the weight that falls down , after the same manner that in a lighted candle surfaces of like sort are separated from the wax or tallow underneath by the heat above , and are extenuated into a most subtil flame . in which it is worth observation , that as that flame doth doubtless take up more then a thousand times a greater space then the part of the wax of which the flame was made took up : so is it here to be thought , that that string doth take up a space more then a thousand times as big as that which the small particle of mercury , from whence it arose , did before take up . as also it doubtless happens when such a particle by a fire underneath is turned into a vapour . p. . corpore , &c. a body taking up a place , for instance , twice as big as it self ; it is of necessity that every part of it must likewise take up a place twice as big as it self . p. . juxta , &c. according to the more probable opinion such a virtual extension of a corporeal being is not to be granted , as being onely proper to such as are spiritual . p. . praestat , &c. it is better to continue in the common opinion , which hath been hitherto received in the schools : which although it doth not clearly resolve all difficulties , yet it doth not openly lye under them . ibid. necessario , &c. we must needs confess that one and the same part must be in two places adequately . for seeing it is indivisible , and takes up a greater place then before , it must of necessity be all in every point of that place , or that be virtually extended through all that space . p. . cum tempus , &c. seeing time is a being essentially successive , so that neither by divine power can two of its parts exist together . p. . respondeo , &c. i answer , that all these things happen because the gun-powder so kindled and turned into flame takes up a much greater space then before . whence it comes to pass that seeing the chamber was before quite full , by this means the walls are broken that there may be no penetration of bodies . p. . partim , &c. sometimes within the chappel , sometimes in the open air ; the wind sometimes blowing , and sometimes being still . p. . sed d'ci , &c. but it may be said , that on the top of the mountain it therefore descended after that manner , because the air was more cold there , or of some other temperature , such as might cause this descent . p. . hoc esse , &c. that this is the difference between pression and suction , that suction makes such an adhesion , and pression doth not . ibid. hoc quoque , &c. and even this experiment doth very well agree with our principles : for seeing by this depression of the sucker , the air shut up in the cavity of the cylinder is separated from the cylinder , and doth descend together with the sucker , ( as we have , chap. . observed of water descending together with quicksilver ) it comes to pass that in that whole depression new surfaces are taken from that descending air , and stretched out , as we have there explained it in the case of descending water . since therefore such sufaces are as easily slipt off and extended in the end of the depression as in the beginning ; it is no wonder that there is found the same difficulty of depressing it at both times . p. . eo magis , &c. that the air is so much the more extended and rarefied , by how much the more is thence exhausted , and so doth acquire a greater force of contracting it self . p. . at profecto , &c. but truly it seems not credible that this most soft air should so vehemently compress a glass on all sides ( especially one of that thickness there mention'd ) as to break it . ibid. verius , &c. it is therefore more truly answered , that the glass is therefore so broken , because by that exsuction its sides are more vehemently drawn inwards then ( by reason of the figure unfit for resistency ) they were able to resist . for seeing the included air doth most firmly stick to the sides of the glass , to draw out the air will be nothing else but to endeavour to bend the sides of the glass inwards . p. . sed profecto , &c. but truly this seems too far remov'd from truth , and may be by this alone sufficiently refuted . because if the pressure of the air which descends by that tube into the vial be so great as to break the vial it self , it ought certainly , before the breaking of the vial , very much to move the water in which the tube is immers'd , and to excite bubbles in it , &c. as appears , if any one blowing through that tube doth make but an ordinary pressure upon the water . but it is sure that the water before the vial is broken doth not move at all : as the experimenter will find . ibid. licet , &c. though the tube had been shut at the top , the vial had doubtless been broken after the same manner . p. . sed rectius , &c. but it is more rightly thence inferr'd , that that cylinder did nothing there before . ibid. dico , &c. i say then that the quicksilver doth by that exhaustion so descend in the tube , because it is drawn downwards by the air incumbent upon the restagnant quicksilver . for that incumbent air , being by its exhaustion greatly rarefied and extended , vehemently contracts it self , and by this contraction doth endeavour to lift the restagnant mercury out of its vessel ; whence it comes to pass that ( the restagnant mercury now less gravitating upon the bottom of its vessel ) the quicksilver in the tube must descend , as is manifest in it self : so that it is no wonder that , the external air afterwards entring , the quicksilver again ascends , seeing by that ingress the force which elevates the restagnant quicksilver is weakned . p. . atque hinc , &c. and hence is a reason also given of another thing which is there noted , namely , that by the violent intrusion of the external air into the receiver the quicksilver ascended considerably above . inches and an half . for as by the extraction of the air the quicksilver is deprest below its station , so by the intrusion of new air it is elevated above it . p. . nam si , &c. for if it were kept up by that , it ought rather to ascend then descend in colder weather , because the air then would be more dense and heavy . therefore the quicksilver is not upheld by the aequilibrium of air , as is asserted . ibid. hinc fit , &c. hence it comes to pass , that this funicle being contracted by the cold , the water doth ascend in cold weather ; but doth descend in hot , because by heat the funicle is dilated . p. . ego certè , &c. i truly do not doubt but there are some such occult causes , by which the slender eunicle that suspends ( as we mentioned in the . chapter ) the quicksilver in the tube is sometimes lengthned , sometimes shortned , and so doth sometimes let down , and sometimes lift up the quicksilver . ibid. in decimo nono , &c. in the . he shews that water doth in the same manner descend upon the exhausting the receiver , as he had shewn quicksilver in the foregoing chapter to descend . of both which seeing there is the same cause , there is no reason we should any longer insist on this . p. . nam si , &c. for if it were done so , these bubbles ought not so to have ascended from the bottom of the vessel , ( as it is asserted they did , both in this and the following experiments that treat of bubbles ) but from the upper part of the water , where they are less comprest ; as it is apparently manifest . p. . respondeo , &c. i answer that the water , upon that exhaustion of the air , doth not so ascend of its own accord , but is violently drawn or lifted upwards by that rarefied air contracting it self . for as water doth suffer some compression ( as appears by experience ) so here also it suffers some distension . and hence it is clearly manifest why these bubbles should arise rather from the bottom of the vessel , then from the upper part of the water . for when that vehement suction doth endeavour to elevate the water from the bottom of the vial , there arises there a certain subtil matter , which being turned into bubbles doth so ascend as is mentioned in the . chapter and the . experiment . p. . certum esse , &c. it is certain that that opinion is sufficiently refuted by this single experiment . p. . necesse , &c. it must needs be that that stone could not otherwise descend , then by leaving behind it such a thin substance as is left by quicksilver or water descending in like manner . p. . unde , &c. whence i plainly conceive that if two perfectlypolish'd marbles were so joyned that no air at all were left between them , they could not be drawn asunder by all the power of man. ibid. uti etiam , &c. which also is confirmed by the example the author there brings of a brass plate sticking so close to a marble table , that by a lusty youth , who boasted of his own strength , it could not be lifted off by a ring fixed to its centre . p. . eodem , &c. almost the same manner as we see in cupping-glasses applied to a patients back , in which the flame being extinct , the rarefied air contracting it self doth so vehemently ( as we see ) lift up , and draw the flesh within the glass . ibid. in his , &c. in these three there is nothing occurs to be peculiarly here explicated , the account of which is not easie from what is already delivered . p. . existimo , &c. but i think that whiteness should be rather called a reflex then an innate light , because , as the author bears witness , it appears not in the dark , but onely in the day , or by candle-light . ibid. verum , &c. but it seems impossible that such animals should dye so soon onely for want of a thicker air. p. . quia per , &c. because by the self-contraction of the rarefied air their breath is drawn out of their bodies . p. . atque hinc , &c. and thence also arose those vehement convulsions , which the author there mentions certain small birds to have endured before their death . p. . in mala , &c. in a bad cause they can do no other ; but who compell'd them to undertake a bad cause ? a summary of the contents of the several chapters . part i. wherein the adversaries objections against the elaterists are examined . chap. . the occasion of this writing , pag. . franciscus linus his civility in writing obliges the author to the like , p. . books concerning the torrecellian experiment wherewith the author was formerly unacquainted , ibid. the inconvenience of linus's principles , ibid. the division of the ensuing treatise into three parts . chap. . a repetition of the adversary's opinion and arguments . his arguments against the weight of the air examined , p. . an experiment of his to prove that the external air cannot keep up twenty inches of quicksilver from descending in a tube twenty inches long , ibid. the authors answer and reconciliation of the experiment to his own hypothesis , p. . and the relation of an experiment of the authors , wherein onely water being employed instead of quicksilver , without other alteration of the adversaries experiment , it agrees well with and confirms the authors hypothesis , and his explication of the mentioned experiments , ibid. that water hath no spring at all , or a very weak one , p. . the second argument examined , ibid. whether the same quantity of air can adequately fill a greater space , p. . the conceivableness of both hypotheses compared , ibid. chap. . another argument of the adversaries , from an experiment wherein the mercury sinking draws the finger into the tube , examined . q. whether the mercury placed in its own station is upheld by the external air , or suspended there by an internal cord ? p. , . chap. . a repetition of franciscus linus his principal experiment , wherein in a tube of twenty inches long the finger on the top is supposed to be strongly drawn and suck'd into the tube , p. . the experiment explicated without the assistance of suction , by the pressure of the external air upon the outside of the finger , thrust , not suck'd in , p. . franciscus linus his argumentation considered , p. . chap. . the examiners last experiment considered , in which he argues against the authors hypothesis , because mercury is not suck'd out of a vessel through a tube so easily as water is , p. , . an experiment of monsieur paschall shewing , that if the upper part of a tube could be freed from the pressure of all internal air , the mercury would by the pressure of the outward air be carried up into the tube as well as water , till it had attained a height great enough to make its weight equal to that of the atmosphere , p. . why in a more forcible respiration the mercurial cylinder is raised higher then in a more languid , p. , . a remark by the bie , that the contraction of the adversaries supposed funiculus is not felt upon the lungs , p. . chap. . the examination of the adversaries . chapter , p. . that the spring of the air may have some advantage in point of force above the weight of it , p. . that it is unintelligible how the same air can adequately fill more space at one time then at another , p. . part ii. wherein the adversaries funicular hypothesis is examined . chap. . wherein what is alledged to prove the funiculus is considered ; and some difficulties are proposed against the hypothesis . the nature of this supposed funiculus described , p. . that according to the adversaries opinion this funiculus is produced by nature onely to hinder a vacuum , p. , . the adversaries proofs that there is no vacuum examined , p. , . that where no sensible part is un-enlightned , the place may not be full of light , p. . the same true in odours , ibid. that there may be matter enough to transmit the impulse of light , though betwixt the particles of that matter there should be store of vacuities intercepted , p. . that a solid body hath no considerable sense of pressure from fluid bodies , p. . of the causes of the vibrations of quicksilver in its descent , p. , . chap. . wherein divers other difficulties are objected against the funicular hypothesis . as that in liquors of divers weights and natures , as water , wine and quicksilver , there should be just the same weight or strength to extend them into a funiculus , p. . that whereas the weight and spring of the air is inferr'd from unquestioned experiments , the account of that hypothesis is strange and unsatisfactory . as that the quicksilver doth not onely touch the top of the glass , but stick to it ; that nature wreaths a little rarefied air into a strong rope even able to draw up quicksilver , p. , . that rarefaction is performed by a certain unknown force , or vis divulsiva , p. . that thin surfaces are left successively one after another , that these surfaces are contrived into strings , that may be stretch'd without being made more slender , &c. p. . the illustration of the manner how his funiculus is made , from the rarefaction of wax or tallow in a lighted candle , is considered , p. . and shewed not to be apposite , ibid. divers other difficulties and improbabilities manifested in the funicular hypothesis , p. . of the inward spring necessary to the contraction of his funiculus , p. , . an argument from a pendulum's moving freely in an exhausted receiver , that the medium it moves in doth not consist of an innumerable exceedingly-stretch'd strings , p. . chap. . the aristotelean rarefaction proposed by the adversary examined . what rarefaction and condensation is , p. . three wayes of explicating how rarefaction is made , p. , . absurdities in resolving the magdeburg experiment by the aristotelean way of rarefaction , p. . the inconveniences of the several hypotheses compared , p. . the difficulties in the adversaries explaining rarefaction by bodies infinitely divisible , p. . the difficulties of explaining it by supposing bodies made up of parts indivisible , p. , . the difficulties wherewith his condensation is incumbred , as that it infers penetration of dimensions , &c. p. . chap. . a consideration pertinent to the present controversie , of what happens in trying the torrecellian and other experiments at the top and feet of hills . that the funicular hypothesis is but an inversion of the elastical , one supposing a spring inwards , the other outwards ; one performing its effects by pulsion , the other by traction , p. . that these tryals on the tops and feet of hills determine the case for the authors hypothesis , p. . the truth of the observation of monsieur paschall confirmed , p. . and the several tryals that have been made of it related , ibid. a tryal of the authors from the leads of the abbey-church at westminster , p. , , . that the subsidence of the mercury at the top of a hill proceeds from the lightness of the atmospherical cylinder there , p. . the relation of an experiment lately made at hallifax hill in confirmation of the former , p. . chap. . two new experiments touching the measure of the force of the spring of the air compress'd and dilated . that it is capable of doing far more then the necessity of the authors hypothesis requires , p. . the first experiment , of compressing air by pouring mercury into a crooked tube , related , p. . wherein the same air being brought to a degree of density twice as great , obtains a spring twice as strong as before , p. . a table of the condensation of the air according to this experiment , p. . particular circumstances observed in the making the experiment , p. . how far the spring of the air may be increased , p. . of the decrement of the force of dilated air , p. . a table of the rarefaction of the air , p. . particular circumstances in making the experiment whence this table was drawn , p. , . that the free air here below appears to be near as strongly comprest by the weight of the incumbent air as it would be by the weight of a mercurial cylinder of . or . inches , p. . part iii. wherein what is objected against mr. boyle's explications of particular experiments is answered . the entrance into this part of the discourse , with an advertisement how far onely it will be requisite to examine the adversaries assertions and explications , the hypotheses on both sides being before considered , p. , . a defence of the first and second experiments , concerning the intrusion of the finger into the orifice of the valve of the evacuated receiver , p. . a defence of the third experiment , why the sucker being drawn down there is no greater difficulty in the end then in the beginnin of the gdepression , p. , . of the fourth experiment , touching the swelling of a bladder upon the exhaustion of the ambient air , and proportionably to that exhaustion , p. , . the authors and the funicular hypothesis in the explication of this phaenomenon compared , ibid. of the fifth experiment , p. . of the eighth experiment , about the breaking of a glass-receiver which was not globular upon the exhaustion of the inward air , p. . whether it were more likely to be broken by the pressure of the atmosphere without , or a contraction of a string of air within , ibid. of the ninth experiment , p. . whether the breaking of the vial outwards in the exhausted receiver , was caused by the pressure of the atmosphere through the tube which was open to the ambient air , ibid. of the . experiment , p. , , , . the torrecellian experiment being made within the receiver , whether the descent and ascent of the mercury in the tube , under and above its wonted station , be caused by the debilitated and strengthned spring of the air , ibid. of the . experiment , p. , . whether the authors or the funicular hypothesis assign the more probable cause why a cylinder of mercury did in winter rise and fall in the tube , sometimes as water in a weather-glass according to the laws of heat and cold , and sometimes contrary thereunto , ibid. of the . experiment , p. . of the . experiment , p. , . some mistakes in the adversary of the authors meaning about the spring of the water , and the places whence the bubbles arose , ibid. the hypotheses compared , ibid. of the . experiment , p. , , . of the cause why the marbles fell not asunder in the exhausted receiver , though a weight of four ounces were hung at the lower stone , ibid. whether the account of the author or adversary be more satisfactory , ibid. of the . and . experiments , of the re-ascent of the sucker and its carrying up a great weight with it upon the exhaustion of the receiver , p. , . how the flesh and neighbouring bloud of a patient is thrust up into a cupping-glass , ibid. of the . experiment , and the cause of the appearance of light or whiteness therein , p. . of the . and . experiments , concerning the cause of the sudden death of animals in the exhausted receiver , p. , . of the . and . experiments , p. . the conclusion , p. , . finis . errata . page . line . lege which pressure notwithstanding , the. p. . l. . hydrargyrum , deprehendit . p. . l. . ut validissimam conficiant cat . p. . l. . quendam funiculum per. p . l. . alamp . p. . l. . physico-mechanical . p. . l. . boylianis . p. . l. . removal : our . p. . l. . quam ut ( ob figuram illam resistendo minus idoneam ) resistere potuerint . notes, typically marginal, from the original text notes for div a -e about the history of flame , of heat , of colours , of the origine of qualities and forms , &c. notes for div a -e pag. . pag. . pag. . pag. . pag. . pag. . pag. . gass . phys . sect. . lib. . pag. . de nupero inanis experimento . pag. . pag. . . pag. . pag. . pag. . pag. . pag. . pag. . pag. . pag. . pag. . pag. . pag. . pag. , . pag. . pag. , . pag. . pag. . pag. . pag. . chap. . pag. ● . pag. . pag. . pag . pag. . † mr. croon one of the learned professors of gresham colledge . * dr. hen. power . see the second figure . * probably these or the like words , did manifest pressure , are here omitted , for the mountaine-aire there seems to have acted rather by its weight then elasticity . page . see the . figure . see part . c . sed contra manifestè . see also in the . experim . these passages , — and this effervescence was so great in the upper part of the water , &c. as also , — the effervescence was confin'd to the upper part of the water , unless , &c. see more concerning this objection in the answer to it as 't is propos'd by mr. hobbes . seven philosophical problems and two propositions of geometry by thomas hobbes of malmesbury ; with an apology for himself and his writings. hobbes, thomas, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) seven philosophical problems and two propositions of geometry by thomas hobbes of malmesbury ; with an apology for himself and his writings. hobbes, thomas, - . [ ], p., folded leaf of plates. printed for william crook, london : . 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ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . geometry -- early works to . - tcp assigned for keying and markup - aptara keyed and coded from proquest page images - judith siefring sampled and proofread - judith siefring text and markup reviewed and edited - pfs batch review (qc) and xml conversion seven philosophical problems , and two propositions of geometry . by thomas hobbes of malmesbury . with an apology for himself , and his writings . dedicated to the king , in the year . london : printed for william crook at the green-dragon without temple-bar , . to the king . that which i do here most humbly present to your sacred majesty , is the best part of my meditations upon the natural causes of events , both of such as are commonly known , and of such as have been of late artificially exhibited by the curious . they are ranged under seven heads . . problems of gravity . . problems of tides . . problems of vacuum . . problems of heat . . problems of hard and soft . . problems of wind and weather . . problems of motion perpendicular , and oblique , &c. to which i have added , two propositions of geometry ; one is , the duplication of the cube , hitherto sought in vain ; the other , a detection of the absurd use of arithmetick , as it is now applied to geometry . the doctrine of natural causes hath not infallible and evident principles . for there is no effect which the power of god cannot produce by many several ways . but seeing all effects are produced by motion , he that supposing some one or more motions can derive from them the necessity of that effect whose cause is required , has done all that is to be expected from natural reason . and though he prove not that the thing was thus produced , yet he proves that thus it may be produced , when the materials , and the power of moving is in our hands ; which is as useful as if the causes themselves were known . and notwithstanding the absence of rigorous demonstration , this contemplation of nature ( if not rendred obscure by empty terms ) is the most noble imployment of the mind that can be , to such as are at leisure from their necessary business . this that i have done i know is anunworthy present to be offered to a king , though considered ( as god considers offerings ) together with the mind and fortune of the offerer , i hope will not be to your majesty unacceptable . but that which i chiefly consider in it is , that my writing should be tryed by your majesties excellent reason untainted with the language that has been invented or made use of by men when they were puzzled ; and who is acquainted with all the experiments of the time ; and whose approbation ( if i have the good fortune to obtain it ) will protect my reasoning from the contempt of my adversaries . i will not break the custom of joyning to my offering a prayer ; and it is , that your majesty will be pleased to pardon this following short apology for my leviathan . not that i rely upon apologies , but upon your majesties most gracious general pardon . that which is in it of theology , contrary to the general current of divines , is not put there as my opinion , but propounded with submission to those that have the power ecclesiastical . i did never after , either in writing or discourse , maintain it . there is nothing in it against episcopacy ; i cannot therefore imagine what reason any episcopal-man can have to speak of me ( as i hear some of them do ) as of an atheist , or man of no religion , unless it be for making the authority of the church wholly upon the regal power ; which i hope your majesty will think is neither atheism nor heresie . but what had i to do to meddle with matters of that nature , seeing religion is not philosophy , but law ? it was written in a time when the pretence of christ's kingdom was made use of for the most horrid actions that can be imagined ; and it was in just indignation of that , that i desired to see the bottom of that doctrine of the kingdom of christ , which divers ministers then preached for a pretence to their rebellion ; which may reasonably extenuate , though not excuse the writing of it . there is therefore no ground for so great a calamny in my writing . there is no sign of it in my life ; and for my religion , when i was at the point of death at st. germains , the bishop of durham can bear witness of it , if he be asked . therefore , i most humbly beseech your sacred majesty not to believe so ill of me upon reports , that proceed often ( and may do so now ) from the displeasure which commonly ariseth from difference in opinion ; nor to think the worse of me , if snatching up all the weapons to fight against your enemies , i lighted upon one that had a double edge . your majesties poor and most loyal subject , thomas ▪ hobbes . philosophical problems ▪ chap. i. problems of gravity . a. what may be the cause , think you , that stones , and other bodies , thrown upward , or carried up and left to their liberty , fall down again ( for ought a man can see ) of their own accord ? i do not think ( with the old philosophers ) that they have any love to the earth , or are sullen , that they will neither go nor stay . and yet i cannot imagine what body there is above that should drive them back . b. for my part , i believe the cause of their descending is not in any natural appetite of the bodies that descend , but rather that the globe of the earth hath some special motion , by the which it more easily casteth off the air , than it doth other bodies . and then this descent of those we call heavy bodies , must of necessity follow ; unless there be some empty spaces in the world to receive them . for when the air is thrown off from the earth , somewhat must come into the place of it , ( in case the world be full ) and it must be those things which are hardliest cast off , that is those things which we say are heavy . a. but suppose there be no place empty ( for i will defer the question till anon ) how can the earth cast off either the air , or any thing else ? b. i shall shew you how , and that by a familiar example . if you lay both your hands upon a basen with water in it , how little soever , and move it circularly , and continue that motion for a while , and you shall see the water rise upon the sides , and fly over ; by which you may be assured that there is a kind of circulating motion , which would cast off such bodies as are contiguous to the body so moved . a. i know very well there is ; and it is the same motion which country people use to purge their corn ; for the chaff and straws , by casting the grain to the side of the seive , will come towards the middle . but i would see the figure . b. here it is . there is a circle pricked out , whose center is a , and three less circles , whose centers are b , c , d ; let every one of them represent the earth , as it goeth from b to c , and from c to d , always touching the uttermost circle , and throwing off the air , as is marked at e and f. and if the world were not full , there would follow by this scattering of the air , a great deal of space left empty . but supposing the world full , there must be a perpetual shifting of the air , one part into the place of another . a. but what makes a stone come down , suppose from g ? b. if the air be thrown up beyond g , it will follow , that at the last , if the motion be continued , all the air will be above g , that is , above the stone ; which cannot be , till the stone be at the earth . a. but why comes it down still with encreasing swiftness ? b. because as it descends , and is already in motion , it receiveth a new impression from the same cause , which is the air , whereof as part mounteth , part also must descend , supposing as we have done the plenitude of the world . for , as you may observe by the figure , the motion of the earth , according to the diameter of the uttermost circle , is progressive ; and so the whole motion is compounded of two motions , one circular , and the other progressive ; and consequently the air ascends and circulates at once . and because the stone descending receiveth a new pressure in every point of its way , the motion thereof must needs be accelerated . a. 't is true ; for it will be accelerated equally in equal times ; and the way it makes will encrease in a double proportion to the times , as hath heretofore been demonstrated by galileo . i see the solution now of an experiment , which before did not a little puzzle me . you know that if two plummets hang by two strings of equal length , and you remove them from the perpendicular equally , i mean in equal angles , and then let them go , they will make their turns and returns together , and in equal times ; and though the arches they describe grow continually less and less , yet the times they spend in the greater arches , will still be equal to the time they spend in the lesser . b. 't is true . do you find any experiment to the contrary ? a. yes ; for if you remove one of the plummets from the perpendicular , so as ( for example ) to make an angle with the perpendicular of degrees , and the other so as to make an angle of degrees , they will not make their turns and returns in equal times . b. and what say you is the cause of this ? a. because the arches are the spaces which these two motions describe , they must be in double proportion to their own times ; which cannot be , unless they be let go from equal altitudes , that is , from equal angles . b. 't is right ; and the experiment does not cross , but confirm the equality of the times in all the arches they describe , even from degrees to the least part of one degree . a. but is it not too bold , if not extravagant , an assertion , to say the earth is moved as a man shakes a basen or a seive ? does not the earth move from west to east every day once , upon his own center , and in the ecliptick circle once a year ? and now you give it another odd motion ; how can all these consist in one and the same body ? b. well enough . if you be a shipboard under sail , do not you go with the ship ? cannot you also walk upon the deck ? cannot every drop of bloud move at the same time in your veins ? how many motions now do you assign to one and the same drop of bloud ? nor is it so extravagant a thing to attribute to the earth this kind of motion ; but that i believe if we certainly knew what motion it is that causeth the descent of bodies , we should find it either the same , or more extravagant . but seeing it can be nothing above that worketh this effect , it must be the earth it self that does it ; and if the earth , then you can imagine no other motion to do it withal , but this ; and you will wonder more , when by the same motion i shall give you a probable account of the causes of very many other works of nature . a. but what part of the heaven do you suppose the poles of your pricked circle point to ? b. i suppose them to be the same with the poles of the ecliptick . for , seeing the axis of the earth in this nation , and in the annual motion keeps parallel to it self , the axis must in both motions be parallel as to sense . for , the circle which the earth describes , is not of visible magnitude at the distance it is from the sun. a. though i understand well enough how the earth may make a stone descend very swiftly under the ecliptick , or not far from it , where it throws off the air perpendicularly ; yet about the poles of the circle methinks it should cast off the air very weakly . i hope you will not say that bodies descend faster in places remote from the poles , than nearer to them . b. no ; but i ascribe it to the like motion in the sun and moon . for such motions meeting , must needs cast the stream of the air towards the poles ; and then there will be the same necessity for the descent there , that there is in other places , though perhaps a little more slowly . for you may have observed that when it snows in the south parts , the flakes of snow are not so great as in the north ; which is a probable sign they fall in the south from a greater height , and consequently disperse themselves more , as water does that falls down from a high and steep rock . a. 't is not improbable . b. in natural causes all you are to expect is but probability ; which is better yet then making gravity the cause , when the cause of gravity is that you desire to know ; and better then saying the earth draws it , when the question is , how it draws ? a. why does the earth cast off air more easily than it does water , or any other heavy bodies ? b. it is indeed the earth that casteth off that air which is next unto it . but it is that air which casteth off the next air ; and so continually air moveth air ; which it can more easily do then any other thing , because like bodies are more susceptible of one anothers motions ; as you may see in two lute-strings equally strained , what motion one string being stricken communicates to the air , the same will the other receive from the air ; but strained to a differing note , will be less , or not at all moved . for there is no body but air that hath not some internal , though invisible motion of its parts . and it is that internal motion which distinguisheth all natural bodies one from another . a. what is the cause why certain squibs , though their substance be either wood or other heavy matter , made hollow and filled with gunpowder , which is also heavy , do nevertheless when the gunpowder is kindled , fly upwards ? b. the same that keeps a man that swims from sinking , though he be heavier then so much water ; he keeps himself up , and goes forward by beating back the water with his feet ; and so does a squib , by beating down the air with the stream of the fired gunpowder , that proceeding from its tail makes it recoil . a. why does any brass or iron vessel , if it be hollow , flote upon the water , being so very heavy ? b. because the vessel and the air in it , taken as one body , is more easily cast off than a body of water equal to it . a. how comes it to pass , that a fish ( especially such a broad fish as a turbut or a plaice , which are broad and thin ) in the bottom of the sea , perhaps a mile deep , is not press'd to death with the weight of water that lies upon the back of it ? b. because all heavy bodies descend towards one point , which is the center of the earth , and consequently the whole sea descending at once does arch it self so , as that the upper parts cannot press the parts next below them . a. it is evident ; nor can there be possibly any weight , as some suppose there is , of a cylinder of air , or water , or of any other liquid thing , while it remains in its own element , or is sustained and inclosed in a vessel , by which one part cannot press the other . chap. ii. problems of tides . a. what makes the flux and reflux of the sea twice in a natural day ? b. we must come again to our basen of water ; wherein you have seen , whilst it was moved , how the water mounteth up by the sides , and withal goes circling round about . now if you should fasten to the inside of the basen some bar from the bottom to the top , you would see the water , instead of going on , go back again from that bar , ebbing , and the water on the other side of the bar to do the same , but in counter-time ; and consequently to be highest where the contrary streams meet together , and then return again , marking out four quarters of the vessel , two by their meeting , which are the high waters , and two by their retiring , which are the low waters . a. what bar is that you find in the ocean , that stops the current of the water , like that you make in the basen ? b. you know that the main ocean lies east and west , between india and the coast of america ; and again , on the other side , between america and india . if therefore the earth have such a motion as i have supposed , it must needs carry the current of the sea east and west ; in which course , the bar that stoppeth it is the south part of america , which leaves no passage for the water , but the narrow streight of magellan . the tide rises therefore upon the coast of america ; and the rising of the same in this part of the world proceedeth from the swelling chiefly of the water there ; and partly also from the north sea , which lieth also east and west , and has a passage out of the south sea by the streight of anian , between america and asia . a. does not the mediterranean-sea lie also east and west ? why are there not the like tides there ? b. so there are , proportionable to their lengths , and quantity of water . a. at genoa , at ancona there are none at all , or not sensible . b. at venice there are , and in the bottom of the streights ; and a current all along both the mediterranean-sea , and the gulf of venice ; and it is the current that makes the tides unsensible at the sides ▪ but the check makes them visible at the bottom . a. how comes it about that the moon hath such a stroke in the business , as so sensibly to encrease the tides at full and change ? b. the motion i have hitherto supposed but in the earth , i suppose also in the moon , and in all those great bodies that hang in the air constantly , i mean the stars , both fixed and errant . and for the sun and moon , i suppose the poles of their motion to be the poles of the aequinoctial ; which supposed , it will follow , ( because the sun , the earth and the moon at every full and change are almost in one streight line ) that this motion of the earth will be made swifter than in the quarters . for this motion of the sun and moon being communicated to the earth , that hath already the like motion , maketh the same greater ; and much greater when they are all three in one streight line , which is only at the full and change , whose tides are therefore called spring tides . a. but what then is the cause that the spring-tides themselves are twice a year , namely when the sun is in the equinoctial , greater than at any other times ? b. at other times of the year , the earth being out of the aequinoctial , the motion thereof , by which the tides are made , will be less augmented , by so much as a motion in the obliquity of degrees or thereabout ( which is the distance between the aequinoctial and ecliptick circles ) is weaker then the motion which is without obliquity . a. all this is reasonable enough , if it be possible that such motions as you suppose in these bodies , be really there . but that is a thing i have some reason to doubt of ; for , the throwing off of air , consequent to these motions , is the cause , you say , that other things come to the earth ; and therefore the like motions in the sun , and moon , and stars , casting off the air , should also cause all other things to come to every one of them . from whence it will follow , that the sun , moon , and earth , and all other bodies but air , should presently come together into one heap . b. that does not follow : for if two bodies cast off the air , the motion of that air will be repress'd both ways , and diverted into a course towards the poles on both sides ; and then the two bodies cannot possibly come together . a. 't is true . and besides , this driving off the air on both sides , north and south , makes the like motion of air there also . and this may answer to the question , how a stone could fall to the earth under the poles of the ecliptick , by the only casting off of air ? b. it follows from hence , that there is a certain and determinate distance of one of these bodies ( the stars ) from another , without any very sensible variation . a. all this is probable enough , if it be true that there is no vacuum , no place empty in all the world. and supposing this motion of the sun and moon to be in the plain of the aequinoctial , methinks that this should be the cause of the diurnal motion of the earth ; and because this motion of the earth is ( you say ) in the plain of the aequinoctial , the same should cause also a motion in the moon on her own center , answerable to the diurnal motion of the earth . b. why not ? what else can you think makes the diurnal motion of the earth , but the sun ? and for the moon , if it did not turn upon its own center , we should see sometimes one , sometimes another face of the moon , which we do not . chap. iii. problems of vacuum . what convincing argument is there to prove , that in all the world there is no empty place ? b. many ; but i will name but one ; and that is , the difficulty of separating two bodies hard and flat laid one upon another ; i say , the difficulty , not the impossibility . it is possible , without introducing vacuum , to pull assunder any two bodies , how hard and flat soever they be , if the force used be greater than the resistance of the hardness . and in case there be any greater difficulty to part them , ( besides what proceeds from their hardness ) then there is to pull them further assunder when they are parted , that difficulty is argument enough to prove there is no vacuum . a. these assertions need demonstration . and first , how does the difficulty of separation argue the plenitude of all the rest of the world ? b. if two flat polish'd marbles lie one upon another , you see they are hardly separated in all points at one and the same instant ; and yet the weight of either of them it is enough to make them slide off one from the other . is not the cause of this , that the air succeeds the marble that so slides , and fills up the place it leaves . a. yes certainly . what then ? b. but when you pull the whole superficies assunder , not without great difficulty , what is the cause of that difficulty ? a. i think as most men do , that the air cannot fill up the space between in an instant ; for the parting is in an instant . b. suppose there be vacuum in that air into which the marble you pull off is to succeed , shall there be no vacuum in the air that was round about the two marbles when they touched ? why cannot that vacuum come into the place between ? air cannot succeed in an instant , because a body ; and consequently cannot be moved through the least space in an instant . but emptiness is not a body , nor is moved , but made by the act it self of separation . there is therefore ( if you admit vacuum ) no necessity at all for the air to fill the space left , in an instant . and therefore , with what ease the marble coming off presseth out the vacuum of the air behind it , with the same ease will the marbles be pulled assunder . seeing then , if there were vacuum , there would be no difficulty of separation ; it follows , because there is difficulty of separation , that there is no vacuum . a. well now , supposing the world full , how do you prove it possible to pull those marbles assunder ? b. take a piece of soft wax ; do not you think the one half touches the other half as close as the smoothest marbles ? yet you can pull them assunder . but how ? still as you pull , the wax grows continually more and more slender ; there being a perpetual parting or discession of the outermost part of the wax one from another ; which the air presently fills , and so there is a continual lessening of the wax , till it be no bigger than a hair , and at last separation . if you can do the same to a pillar of marble , till the outside give way , the effect will be the same , but much quicker , after it once begins to break in the superficies ; because the force that can master the first resistance of the hardness , will quickly dispatch the rest . a. it seems so by the brittleness of some hard bodies . but i shall afterward put some questions to you , touching the nature of hardness . but now to return to our subject , what reason can you render ( without supposing vacuum ) of the effects produced in the engine they use at gresham colledge ? b. that engine produceth the same effects , that a strong wind would produce in a narrow room . a. how comes the wind in ? you know the engine is a hollow round pipe of brass ; into which is thrust a cylinder of wood covered with leather , and fitted to the cylinder so exactly as no air can possibly pass between the leather and the brass ? b. i know it ; and that they may thrust it up , there is a hole left in the cylinder to let the air out before it ; which they can stop when they please . there is also in the bottom of the cylinder a passage into a hollow globe of glass ; which passage they can also open and shut at pleasure . and at the top of that globe there is a wide mouth to put in what they please to try conclusions on ; and that also to be opened and shut as shall be needful . 't is of the nature of a pop-gun which children use , but great , costly , and more ingenious . they thrust forward , and pull back the wooden cylinder ( because it requires much strength ) with an iron screw . what is there in all this to prove the possibility of vacuum . a. whan this wooden cylinder covered with leather , fit and close is thrust home to the bottom , and the holes in the hollow cylinder of brass close stopped , how can it be drawn back , as with the screw they draw it , but that the space it leaves must needs be empty . for it is impossible that any air can pass into the place to fill it ? b. truly i think it close enough to keep out straw and feathers , but not to keep out air , nor yet matter . for suppose they were not so exactly close but that there were round about a distance for a small hair to lye between , then will the pulling back of the cylinder of wood force so much air in , as in retiring it forces back , and that without any sensible difficulty . and the air will so much more swiftly enter as the passage is left more narrow . or if they touch , and the contract be in some points , and not in all , the air will enter as before in case the force be augmented accordingly . lastly , though they touch exactly , if either the leather yield , or the brass ( which it may do to the force of a strong screw ) the air will again enter . do you think it possible to make two superficies so exquisitly touch in all points as you suppose , or leather so hard as not to yield to the force of a screw ? the body of leather will give passage both to air and water , as you will confess when you ride in rainy and windy weather . you may therefore be assured that in drawing out their wooden-leather cylinder they force in as much air as will fill the place it leaves , and that with as much swiftness as is answerable to the strength that drives it in . the effect therefore of their pumping is nothing else but a vehement wind , a very vehement wind coming in on all sides of the cylinder at once into the hollow of the brass pipe , and into the hollow of the glass globe joyned to it . a. i see the reason already of one of their wonders , which is , that the cylinder they pump with , if it be left to it self , after it is pulled back will swiftly go up again . you will say the air comes out again with the same violence by reflection ; and i believe it ? b. this is argument enough that the place was not empty . for what can fetch or drive up the sucker , as they call it , if the place within were empty ; for that there is any weight in the air to do it , i have already demonstrated to be impossible . besides , you know , when they have sucked out ( as they think ) all the air from the glass globe , they can nevertheless both see through it what is done , and hear a sound from within when there is any made . which ( if there were no other , but there are many other , ) is argument enough that the place is still full of air. a. what say you to the swelling of a bladder even to bursting , if it be a little blown when it is put into the receiver , ( for so they call the globe of glass ? ) b. the stream of air that from every side meeting together , and turning in an infinite number of small points , do pierce the bladder in innumerable places with great violence at once , like so many invisible small wimbles ; especially if the bladder be a little blown before it be put in , that it may make a little resistance . and when the air has once pierced it , it is easie to conceive , that it must afterward by the same violent motion be extended till it break . if before it break you let in fresh air upon it , the violence of the motion will thereby be tempered , and the bladder be less extended . for that also they have observed . can you imagine how a bladder should be extended , and broken , by being too full of emptiness . a. how come living creatures to be killed in this receiver , in so little a time as or minutes of an hour ? b. if they suck into their lungs so violent a wind thus made , you must needs think it will presently stop the passage of their bloud ; and that is death ; though they may recover if taken out before they be too cold . and so likewise will it put out fire ; but the coals taken out whilst they are hot , will revive again . 't is an ordinary thing in many coal-pits , ( whereof i have seen the experience , ) that a wind proceeding from the sides of the pit every way , will extinguish any fire let down into it , and kill the workmen , unless they be quickly taken out . a. if you put a vessel of water into the receiver , and then suck out the air , the water will boil . what say you to that ? b. it is like enough it will dance in so great a bustling of the air ; but i never heard it would be hot . nor can i imagine how vacuum should make any thing dance . i hope you are by this time satisfied , that no experiment made with the engine at gresham colledge , is sufficient to prove that there is , or that there may be vacuum . a. the world you know is finite , and consequently , all that infinite space without it , is empty . why may not some of that vacuum be brought in , and mingled with the air here ? b. i know nothing in matters without the world. a. what say you to torricellioes experiment in quick-silver , which is this . there is a bason at a filled with quick-silver , suppose to b , and cd a hollow glass pipe filled with the same . which if you stop with your finger at b , and so set it upright , and then if you take away your finger , the quick-silver will fall from c downwards , but not to the bottom . for it will stop by the way , suppose at d. is it not therefore necessary that that space between c and d be left empty ? or will you say the quick silver does not exactly touch the sides of the glass pipe ? b. i 'le say neither . if a man thrust down into a vessel of quick-silver a blown bladder , will not that bladder come up to the top ? a. yes certanly , or a bladder of iron , or of any thing else but gold. b. you see then that air can pierce quick-silver . a. yes , with so much force as the weight of quick-silver comes to . b. when the quick-silver is fallen to d , there is so much the more in the bason . and that takes up the place which so much air took up before . whither can this air go if all the world without that glass pipe b c were full ? there must needs be the same or as much air come to that space ( which only is empty ) between c and d. by what force ? by the weight of the quick-silver between d and b. which quick-silver weigheth now upward ; or else it could never have raised that part higher , which was at first in the bason . so you see the weight of quick-silver can press the air through quick-silver up into the pipe , till it come to an equality of force as in d. where the weight of the quick-silver is equal to the force which is required in air to go through it . a. if a man suck a vial that has nothing in it but air , and presently dip the mouth of it into water , the water will ascend into the vial. is not that an argument that part of the air had been sucked out , and part of the room within the vial left empty ? b. no. if there were empty space in the world , why should not there be also some empty space in the vial before it was sucked ? and then why does not the water rise to fill that , when a man sucks the vial he draws nothing out neither into his belly not into his lungs , nor into his mouth ; only he sets the air within the glass into a circular motion , giving it at once an endeavour to go forth by the sucking , and an endeavour to go back by not receiving it into his mouth . and so with a great deal of labour glues his lips to the neck of the vial. then taking it off , and dipping the neck of the vial into the water before the circulation cease , the air with the endeavour it hath now gotten , pierces the water and goes out . and so much air as goes out , so much matter comes up into the room of it . chap. iiii. problems of heat and light. a. what is the cause of heat ? b. how know you , that any thing is hot but your self ? a. because i perceive by sense it heats me . b. it is no good argument , the thing heats me ; therefore it is hot. but what alteration do you find in your body at any time by being hot ? a. i find my skin more extended in summer than in winter ; and am sometimes fainter and weaker then ordinary , as if my spirits were exhaled ; and i sweat . b. then that is it you would know the cause of . i have told you before that by the motion i suppose both in the sun , and in the earth , the air is dissipated , and consequently that there would be an infinite number of small empty places but that the world being full , there comes from the next parts other air into the spaces , they would else make empty . when therefore this motion of the sun is excercised upon the superficies of the earth , if there do not come out of the earth it self some corporal substance to supply that tearing of the air , we must return again to the admission of vacuum . if there do , then you see how by this motion fluid bodies are made to exhale out of the earth . the like happens to a mans body or hand , which when he perceives , he says he is hot. and so of the earth when it sendeth forth water and earth together in plants , we say it does it by heat from the sun. a. 't is very probable , and no less probable , that the same action of the sun , is that which from the sea and moist places of the earth , but especially from the sea fetcheth up the water into the clouds . but there be many ways of heating besides the action of the sun or of fire . two pieces of wood will take fire if in torning they be prest together . b. here again you have a manifest laceration of the air by the reciprocal and contrary motions of the two pieces of wood , which necessarily causeth a coming forth of whatsoever is aereal or fluid within them , and ( the motion pursued ) a dissipation also of the other more solid parts into ashes . a. how comes it to pass that a man is warmed even to sweating almost with every extraordinary labour of his body ? b. it is easie to understand , how by that labour all that is liquid in his body is tossed up and down , and thereby part of it also cast forth . a. there be some things that make a man hot without sweat or other evaporation , as caustiques , nettles and other things . b. no doubt . but they touch the part they so heat , and cannot work that effect at any distance . a. how does heat cause light , and that partially in some bodies more , in some less , though the heat be equal ? b. heat does not cause light at all . but in many bodies , the same cause , that is to say , the same motion causeth both together ; so that they are not to one another as cause and effect , but are concomitant effects , sometimes of one and the same motion . a. how ? b. you know the rubbing or heard pressing of the eye , or a stroke upon it makes an apparition of light without and before it , which way soever you look . this can proceed from nothing else but from the restitution of the organ pressed or stricken , unto its former ordinary situation of parts . does not the sun by his thrusting back the air upon you eyes press them ? or does not those bodies whereon the sun shines ( though by reflection ) do the same , though not so strongly ? and do not the organs of sight , the eye , the heart , and brains resist that pressure by an endeavour of restitution outwards ? why then should there not be without and before the eye , an apparition of light in this case as well as in the other ? a. i grant there must . but what is that which appears after the pressing of the eye ? for there is nothing without , that was not there before ; or if there were , methinks another should see it better , or as well as he ; or if in the dark , methinks it should enlighten the place . b. it is a fancy , such as is the appearance of your face in a looking-glass ; such as is a dream ; such as is a ghost ; such as is a spot before the eye that hath stared upon the son or fire . for all these are of the regiment of fancy , without any body concealed under them , or behind them , by which they are produced . a. and when you look towards the sun or moon , why is not that also which appears before your eyes at that time a fancy ? b. so it is . though the sun it self be a real body , yet that bright circle of about a foot diameter cannot be the sun , unless there be two suns , a greater and a lesser . and because you may see that which you call the sun , both above you in the skie , and before you in the water , and two suns ( by distorting your eye ) in two places of the skie , one of them must needs be fancy . and if one , both . all sense is fancy though the cause be always in a real body . a. i see by this that those things which the learned call the accidents of bodies , are indeed nothing else but diversity of fancy ; and are inherent in the sentient , and not in the objects , except motion and quantity . and i perceive by your doctrine you have been tampering with leviathan . but how comes wood with a certain degree of heat to shine , and iron also with a greater degree ; but no heat at all to be able to make water shine ? b. that which shineth hath the same motion in its parts that i have all this while supposed in the sun and earth . in which motion there must needs be a competent degree of swiftness , to move the sense , that is , to make it visible . all bodies that are not fluid will shine with heat , if the heat be very great . iron will shine and gold will shine ; but water will not , because the parts are carried away before they attain to that degree of swiftness ; which is requisite . a. there are many fluid bodies , whose parts evaporate , and yet they make a flame , as oyl , and wine , and other strong drinks : b. as for oyl i never saw any inflamed by it self ; how much soever heated , therefore i do not think they are the parts of the oyl , but of the combustible body oyled that shine , but the parts of wine and strong drinks have partly a strong motion of themselves , and may be made to shine , but not with boiling , but by adding to them as they rise the flame of some other body . a. how can it be known that the particles of wine have such a motion as you suppose ? b. have you ever been so much distempered with drinking wine , as to think the windows and table move ? a. i confess ( though you be not my confessor , ) i have , but very seldom , and i remember the window seemed to go and come in a kind of circling motion , such as you have described . but what of that ? b. nothing , but that it was the wine that caused it ; which having a good degree of that motion before , did when it was heated in the veins , give that concussion ( which you thought was in the window , ) to the veins themselves , and ( by the continuation of the parts of mans body ) to the brain ; and that was it which made the window seem to move . a. what is flame ? for i have often thought the flame that comes out of a small heap of straw , to be more ( before it hath done flaming , ) then a hundred times the straw it self . b. it was but your fancy . if you take a stick in your hand by one end , the other end burning , and move it swiftly , the burning end , if the motion be circular , shall seem a circle ; if streight , a streight line of fire , longer or shorter , according to the swiftness of the motion , or to the space it moves in . you know the cause of that . a. i think it is , because the impression of that visible object , which was made at the first instant of the motion did last till it was ended . for then it will follow that it must be visible all the way , the impressions in all points of the time being equal . b. the cause can be no other . the smallest spark of fire flying up seems a line drawn upward ; and again by that swift circular motion which we have supposed for the cause of light , seems also broader then it is . and consequently the flame of every thing must needs seem much greater then it is . a. what are those sparks that flie out of the fire ? b. they are small pieces of the wood or coals , or other fuel loosened and carried away with the air that cometh up with them . and being extiguished before their parts be quite dissipated into others , are so much soot , and black , and may be fired again . a. a spark of fire may be stricken out of a cold stone . it is not therefore heat that makes this shining . b. no 't is the motion that makes both the heat and shining ; and the stroke makes the motion . for every of those sparks , is a little parcel of the stone , which swiftly moved , imprinteth the same motion into the matter prepared , or 〈◊〉 receive it . a. how comes the light of the sun to burn almost any combustible matter by rerefraction through a convex glass , and by reflection from a concave ? b. the air moved by the sun presseth the convex glass in such manner as the action continued through it , proceedeth not in the same streight line by which it proceeded from the sun , but tendeth more toward the center of the body it enters . also when the action is continued through the convex body it bendeth again the same way . by which means the whole action of the sun-beams are enclosed within a very small compass ; in which place therefore there must be a very vehement motion ; and consequently if there be in that place combustible matter , such as is not very hard kindle , the parts of it will be dissipated , and receive that motion which worketh on the eye as other fire does . the same reason is to be given for burning by reflection . for there also the beams are collected into almost a point . a. why may not the sun-beams be such a body as we call fire , and pass through the pores of the glass so disposed as to cary them to a point , or very near ? b. can there be a glass that is all pores ; if there cannot , then cannot this effect be produced by the passing of fire through the pores . you have seen men llght their tobacco at the sun with a burning glass , or with a ball of cristal , held which way they will indifferently . which must be impossible , unless the ball were all pores . again , neither you nor i can conceive any other fire then we have seen , nor then such as water will put out . but not only a solid globe of glass or cristal will serve for a burning glass , but also a hollow one filled with water . how then does the fire from the sun pass through the glass of water without being put out before it come to the matter they would have it burn ? a. i know not . there comes nothing from the sun. if there did , there is come so much from it already , that at this day we had had no sun , chap. v. problems of hard and soft . a. what call you hard , and what soft . b. that body whereof no one part is easily put out of its place , without removing the whole , is that which i and all men call hard ; and the contrary soft . so that they , are but degrees one of another . a. what is the cause that makes one body harder then another , or ( seeing you say they are but degrees of one another ) what makes one body softer then another , and the same body sometimes harder , sometimes softer ? b. the same motion which we have supposed from the beginning for the cause of so many other effects . which motion not being upon the center of the part moved , but the part it self going in another circle to and again , it is not necessary that the motion be perfectly circular . for it is not circulation , but the reciprocation , i mean the to and again that does cast off , and lacerrate the air , and consequently produce the fore-mentioned effects . for the cause therefore of hardness , i suppose the reciprocation of motion in those things which are hard , to be very swift , and in very small circles . a. this is somewhat hard to believe . i would you could supply it with some visible experience . b. when you see ( for example ) a cross-bow bent , do you think the parts of it stir ? a. no. i am sure they do not . b. how are you sure ? you have no argument for it , but that you do not see the motion . when i see you sitting still , must i believe there is no motion in your parts within , when there are so many arguments to convince me there is . a. what argument have you to convince me that there is motion in a cross-bow when it stands bent ? b. if you cut the string , or any way set the bow at liberty it will have then a very visible motion . what can be the cause of that ? a. why the setting of the bow at liberty . b. if the bow had been crooked before it was bent , and a string tied to both ends , and then cut asunder , the bow would not have stir'd . where lies the difference ? a. the bow bent has a spring ; unbent it has none , how crooked soever . b. what mean you by spring ? a. an endeavour of restitution to it's former posture . b. i understand spring as well as i do endeavour . a. i mean a prnciple or beginning of motion in a contrary way to that of the force which bent it . b. but the beginning of motion is also motion , how insensible soever it be . and you know that nothing can give a beginning of motion to it self . what is it therefore that gives the bow ( which you say you are sure was at rest when it stood bent ) its first endeavour to return to its former posture ? a. it was he that bent it . b. that cannot be . for he gave it an endeavour to come forward , and the bow endeavours to go backward . a. well , grant that endeavour be motiou , and motion in the bow unbent , how do you derive from thence , that being set at liberty it must return to its former posture ? b. thus there being within the bow a swift ( though invisible ) motion of all the parts , and consequently of the whole ; the bending causeth that motion , which was along the bow ( that was beaten out when it was hot into that length ) to operate a cross the length in every part of it , and the more by how much it is more bent ; and consequently endeavours to unbend it all the while it stands bent . and therefore when the force which kept it bent is removed , it must of necessity return to the posture it had before . a. but has that endeavour no effect at all before the impediment be removed ? for if endeavour be motion , and every motion have some effect more or less , methinks this endavour should in time produce something . b. so it does . for in time ( in a long time ) the course of this internal motion will lie along the bow , not according to the former , but to the new acquired posture . and then it will be as uneasie to return it to its former posture , as it was before to bend it . a. that 's true . for bows long bent lose their appetite to restitution , long custom becoming nature . but from this internal reciprocation of the parts , how do you infer the hardness of the whole body . b. if you apply force to any single part of such a body , you must needs disorder the motion of the next parts to it before it yield , and there disordered , the motion of the next again must also be disordered ; and consequently no one part can yield without force sufficient to disorder all . but then the whole body must also yield . now when a body is of such a nature as no single part can be removed without removing the whole , men say that body is hard. a. why does the fire melt divers hard bodies , and yet not all ? b. the hardest bodies are those wherein the motion of the parts are the most swift , and yet in the least circles . wherefore if the fire , the motion of whose parts are swift , and in greater circiles , he made so swit , as to be strong enough to master the motion of the parts of the hard body , it will make those parts to move in a greater compass , and thereby weaken their resistance , that is to say , soften them , which is a degree of liquefaction . and when the moton is so weakened , as that the parts lose their coherence by the force of their own weight , then we count the body melted . a. why are the hardest things the most brittle , insomuch that what force soever is enough to bend them , is enough also to break them ? b. in bending a hard body , as ( for example ) a rod of iron , you do not inlarge the space of the internal motion of the parts of iron , as the fire does ; but you master and interrupt the motion , and that chiefly in one place . in which place the motion that makes the iron hard being once overcome , the prosecution of that bending must needs suddenly master the motions of the parts next unto it , being almost mastered before . a. i have seen a small piece of glass , the figure whereof is this a a b c. which piece of glass if you bend toward to top , as in c , the whole body will shatter asunder into a million of pieces , and be like to so much dust . i would fain see you give a probable reason of that . b. i have seen the experiment . the making of the glass , is thus , they dip an iron rod into the molten glass that stands in a vessel within the furnace . upon which iron rod taken out , there will hang a drop of molten but tough mettal of the figure you have described , which they let fall into the water . so that the main drop comes first to the water , and after it the tail , which though streight whilst it hung on the end of the rod , yet by falling into the water becomes crooked . now you know the making of it , you may consider what must be the consequence of it . because the main drop a comes first to the water , it is therefore first quenched , and consequently that the motion of the parts of that drop , which by the fire were made to be moved in a larger compass , is by the water made to shrink into lesser circles towards the other end b , but with the same or not much less swiftness . a. why so ? b. if you take any long piece of iron , glass , or other uniform and continued body ; and having heated one end thereof , you hold the other end in your hand , and so quench it suddenly , though before , you held it easily enough , yet now it will burn your fingers . a. it will so . b. you see then how the motion of the parts from a toward c is made more violent and in less compass by quenching the other parts first . besides , the whole motion that was in all the parts of the main drop a , is now united in the small end b c. and this i take to be the cause why that small part b c is so exceeding stiff . seeing also this motion in every small part of the glass , is not only circular , but proceeds also all along the glass from a to b , the whole motion compounded will be such as the motion of spinning any soft matter unto thread , and will dispose the whole body of the glass in threads , which in other hard bodies are called the grain . therefore if you bend this body ( for example ) in c ( which to do will require more force then a man would think that has not tryed ) those threads of glass must needs be all bent at the same time , and stand so , till by the breaking of the glass at c , they be all at once set at liberty . and then all at once being suddenly unbent , like so many brittle , and over-bent bows , their strings breaking , be shivered in pieces . a. 't is like enough to be so . and if nature have betrayed her self in any thing , i think it is in this , and in that other experience of the cross-bow ; which strongly and evidently demonstrates the internal reciprocation of the motion , which you suppose to be in the internal parts of every hard body . and i have observed somewhat in looking-glasses which much confirms that there is some such motion in the internal parts of glass , as you have supposed for the cause of hardness . for let the glass be a b , and let the object at c be a candle , and the eye at d. now by divers reflections and refractions in the two superficies of the glass , if the lines of vision be very oblique , you shall see many images of the candle , as e , f , g , in such order and position as is here described . but if you remove your eye to c , and the candle to d , they will appear in a situation manifestly different from this . which you will yet more plainly perceive if the looking-glass be coloured , as i have obseved in red and blew glasses ; and could never conceive any probable cause of it , till now you tell me of this secret motion of the parts across the grain of the glass , acquired by cooling it this or that way . b. there be very many kinds of hard bodies , metals , stones , and other kinds in the bowels of the earth , that have been there ever sence the beginning of the world ; and i believe also many different sorts of juices that may be made hard. but for one general cause of hardness it can be no other then such an internal motion of parts as i have already described , whatsoever may be the cause of the several concomitant qualities of their hardness in particular . a. we see water hardened every frosty day . it 's likely therefore you may give a pribable cause of ice . what is the cause of freezing of the ocean towards the poles of the earth ? b. you know the sun being always between the tropicks , and ( as we have supposed ) always casting off the air ; and the earth likewise casting it off from it's self , there must needs on both sides be a great stream of air towards the poles , shaving the superficies of the earth and sea , in the northern and southern climates . this shaving of the earth and sea by the stream of air must needs contract and make to shrink those little circles of the internal parts of earth and water , and consequently harden them , first at the superficies , into a thin skin , which is the first ice ; and afterwards the same motion continuing , and the first ice co-operating , the ice becomes thicker . and this i conceive to be the cause of the freezing of the ocean . a. if that be the cause , i need not ask how a bottle of water is made to freeze in warm weather with snow , or ice mingled with salt. for when the bottle is in the midst of it , the wind that goeth out both of the salt and of the ice as they dissolve , must needs shave the superficies of the bottle , and the bottle work accordingly on the water without it , and so give it first a thin skin , and at last thicken it into a solid piece of ice . but how comes it to pass that water does not use to freeze in a deep pit ? b. a deep pit is a very thick bottle , and such as the air cannot come at but only at the top , or where the earth is very loose and spungy . a. why will not wine freeze as well as water ? b. so it will when the frost is great enough . but the internal motion of the parts of wine and other heating liquors is in greater circles and stronger then the motion of the parts of water ; and therefore less easily to be frozen , especally quite through , because those parts that have the strongest motion retire to the center of the vessel . chap. vi. problems of rain , wind , and other weather . a. what is the original cause of rain ? and how is it generated ? b. the motion of the air ( such as i have described to you already ) tending to the dis-union of the parts of the air , must needs cause a continual endeavour ( there being no possibility of vacuum ) of whatsoever fluid parts there are upon the face of the earth and sea , to supply the place which would else be empty . this makes the water , and also very small and loose parts of the earth and sea to rise , and mingle themselves with the air , and to become mist and clouds . of which the greatest quantity arise there , where there is most water , namely , from the large parts of the ocean ; which are the south sea , the indian sea , and the sea that divideth europe and africa from america ; over which the sun , for the greatest part of the year is perpendicular , and consequently raiseth a greater quantity of water . which afterwards gathered into clouds , falls down in rain . a. if the sun can thus draw up the water ; though but in small drops , why can it not as easily hold it up ? b. it is likely it would also hold them up , if they did not grow greater by meeting together , nor were carried away by the air towards the poles . a. what makes them gather together ? b. it is not improbable that they are carried against hills , and there stopt till more overtake them . and when they are carried towards the north or south where the force of the sun is more oblique and thereby weaker , they descend gently by their own weight . and because they tend all to the center of the earth , they must needs be united in their way for want of room , and so grow bigger . and then it rains. a. what is the reason it rains so seldom , but snows so often upon very high mountains ? b. because perhaps when the water is drawn up higher then the highest mountains , where the course of the air between the aequator and the poles is free from stopping , the stream of the air freezeth it into snow . and 't is in those places only where the hills shelter it from that stream , that it falls in rain . a. why is there so little rain in egypt , and yet so much in other parts nearer the aequinoctial , as to make the nile overflow the countrey ? b. the cause of the falling of rain , i told you was the the stopping , and consequently the collection of clouds about great mountains , especially when the sun is near the aequinoctial , and thereby draws up the water more potently , and from greater seas . if you consider therefore that the mountains in which are the springs of nile , lye near the aequinoctial and are exceeding great , and near the indian sea , you will not think it strange there should be great store of snow . this as it melts makes the rain of nile to rise , which in april and may going on toward egypt arrived there about the time of the solstice , and overflow the countrey . a. why should not the nile then overflow that countrey twice a year ? for it comes twice a year to the aequinoctial . b. from the autumnal aequinox , the sun goeth on toward the southern tropique . and therefore cannot dissolve , the snow on that side of the hills that look towards egypt . a. but then there ought to be such another innundation southward . b. no doubt but there is a greater descent of water there in their summer then at other times ; as there must be wheresoever there is much snow melted . but what should that innundate , unless it should overflow the sea that comes close to the foot of those mountains ? and for the cause why it seldom rains in egypt , it may be this , that there are no very high hills near it to collect the clouds . the mountains whence nile riseth being near miles off . the nearest on one side are the mountains of nubia , and on the other side sina , and the mountains of arrabia . a. whence think you proceed the winds ? b. from the motion ( i think ) especially of the clouds , partly also from whatsoever is moved in the air. a. it is manifest , that the clouds are moved by the winds ; so that there were winds before any clouds could be moved . therefore i think you make the effect before the cause . b. if nothing could move a cloud but wind , your objection were good . but you allow a cloud to descend by it's own weight . but when it so descends , it must needs move the air before it , even to the earth , and the earth again repel it , and so make lateral winds every way . which will carry forwards other clouds if there be any in their way , but not the cloud that made them the vapour of the water rising into clouds , must needs also as they rise , raise a wind ? a. i grant it . but how can the slow motion of a cloud make so swift a wind as it does ? b. it is not one or two little clouds , but many and great ones that do it . besides , when the air is driven into places already covered ; it cannot but be much the swifter for the narrowness of the passage a. why does the south wind more often then any other bring rain with it ? b. where the sun hath most power , and where the seas are greatest , that is in the south , there is most water in the air ; which a south wind can only bring to us . but i have seen great showers of rain sometimes also when the wind hath been north , but it was in summer , and came first , i think , from the south or west , and was but brought back from the north. a. i have seen at sea very great waves when there was no wind at all . what was it then that troubled the water ? b. but had you not wind enough presently after ? a. we had a storm within a little more then a quarter of an hour after . b. that storm was then coming and had moved the water before it . but the wind you could not perceive , for it came downwards with the descending of the clouds , and pressing the water bounded above your sail till it came very near . and that was it that made you think there was no wind at all . a. how comes it to pass that a ship should go against the wind which moves it , even almost point blank , as if it were not driven but drawn ? b. you are to know first , that what body soever is carryed against another body , whether perpendicularly , or obliquely , it drives it in a perpendicular to the superficies it lighteth on . as for example , a bullet shot against a flat wall , maketh the stone ( or other matter it hits ) to retire in a perpendicular to that flat ; or , if the wall be round , towards the center , that is to say , perpendicularly . for if the way of the motion be oblique to the wall , the motion is compounded of two motions , one parrallel to the wall , and the other perpendicular . by the former whereof the bullet is carried along the wall side , by the other it approacheth to it . now the former of these motions can have no effect upon it ; all the battery is from the motion perpendicular , in which it approacheth . and therefore the part it hits must also retire perpendicularly . if it were not so , a bullet with the same swiftness would execute as much obliquely shot , as perpendicularly ; which you know it does not . a. how do you apply this to a ship ? b. let a. b. be the ship , the head of it a. if the wind blow just from a. towards b. 't is true , the ship cannot go forward howsoever the sail be set . let c. d. be perpendicular to the ship , and let the sail e. c. be never so little oblique to it , and f. c. perpendicular to e. c. and then you see the ship will gain the space d. f. to the headward . a. it will so , but when it is very near to the wind it will go forward very slowly , and make more way with her side to the leeward . a. it will indeed go slower in the proportion of the line a. e. to the line c. e. but the ship will not go so fast as you think sideward : one is the force of that wind which lights on the side of the ship it self ; the other is , the bellying of the sail ; for the former , it is not much because the ship does not easily put from her the water with her side ; and bellying of the sail , gives some little hold for the wind to drive the ship a stern . a. for the motion sideward i agree with you ; but i had thought the bellying of the sail , had made the ship go faster . b. but it does not ; only in a fore-wind it hinders least . a. by this reason a broad thin board should make the best sail. b. you may easily foresee the great incommodities of such a sail. but i have seen tryed in little what such a wind can do in such a case . for i have seen a board set upon four truckles , with a staff set up in the midst of it for a mast , and another very thin and broad board fastned to that staff in the stead of a sail ; and so set as to receive the wind very obliquely , i mean so as to be within a point of the compass directly opposite to it ; and so placed upon a reasonable smooth pavement where the wind blew somewhat strongly . the event was first , that it stood doubting whether it should stir at all or no , but that was not long ; and then it ran a head extream swiftly , till it was overthrown by a rub. a. before you leave the ship tell me how it comes about that so small a thing as a rudder , can so easily turn the greatest ship ? b. 't is not the rudder only , there must also be a stream to do it ; you shall never turn a ship with a rudder in a standing pooll , nor in a natural current . you must make a stream from head to stern , either with oares or with sails : when you have made such a stream , the turning of the rudder obliquely holds the water from passing freely ; and the ship or boat cannot go on directly , but as the rudder inclines to the stern , so will the ship turn . but this is too well known to insist upon : you have observed , that the rudders of the greatest ships are not very broad , but go deep into the water , whereas western barges , though but small vessels , have their rudders much broader , which argues that the holding of water from passing is the office of a rudder : and therefore to a ship that draws much water the rudder is made deep accordingly , and in barges that draw little water , the rudders as less deep , must so much the more be extended in breadth . a. what makes snow ? b. the same cause which ( speaking of hardness ) i supposed for the cause of ice . for the stream of air proceeding from . that both the earth and the sun cast off the air , and consequently maketh a stream of air from the aequinoctial towards the poles , passing amongst the clouds , shaving those small drops of water whereof the clouds consist , and congeals them as they do the water of the sea , or of a river . and these small frozen drops are that which we call snow . a. but then how are great drops frozen into hailstones , and that especially ( as we see they are ) in summer ? b. it is especially in summer ; and hot weather , that the drops of water which make the clouds , are great enough ; but it is then also that clouds are sooner and more plentifully carryed up . and therefore the current of the air strengthned between the earth and the clouds , becomes more swift ; and thereby freezeth the drops of water , not in the cloud it self , but as they are falling . nor does it freeze them throughly , the time of their falling not permitting it , but gives them only a thin coat of ice ; as is manifest by their suddain dissolving . a. why are not somteimes also whole clouds when pregnant and ready to drop , frozen into one piece of ice ? b. i belive they are so whensoever it thunders . a. but upon what ground do you believe it ? b. from the manner or kind of noise they make , namely a crack ; which i see not how it can possibly be made by water or any other soft bodies whatsoever . a. yes , the powder they call aurum fulminans , when throughly warm , gives just such another crack as thunder . b. but why may not every small grain of that aurum fulminans by it self be heard , though a heap of them together be soft , as is any heap of sand. salts of all sorts are of the nature of ice . but gold is dissolved into aurum fulminans by nitre and other salts . and the least grain of it gives a little crack in the fire by it self . and therefore when they are so warmed by degrees , the crack cannot chuse but be very great . a. but before it be aurum fulminans they use to wash away the salt ( which they call dulcifying it , ) and then they dry it gently by degrees . b. that is , they exhale the pure water that is left in the powder , and leave the salt behind to harden with drying . other powder made of salts without any gold in them will give a crack as great as aurum fulminans . a very great chymist of our times hath written , that salt of tarter , salt-peter , and a little brimstone ground together into a powder , and dryed , a few grains of that powder will be made by the fire to give as great a clap as a musquet . a. me thinks it were worth your tryal to see what effect a quart or a pint of aurum fulminans would produce , being put into a great gun made strong enough on purpose , and the breech of the gun set in hot cinders , so as to heat by degrees , till the powder fly . b. i pray you try it your self ; i cannot spare so much money . a. what is it that breaketh the clouds when they are frozen ? b. in very hot weather the sun raiseth from the sea and all moist places abundance of water , and to a great height . and whilst this water hangs over us in clouds , or is again descending , it raiseth other clouds , and it hapens very often that they press the air between them , and squeeze it through the clouds themselves very violently ; which as it passes shaves and hardens them in the manner declared . a. that has already been granted , my question is what breaks them ? b. i must here take in one supposition more . a. then your basen ( it seems ) holds not all you have need of . b. it may for all this , for the supposition i add is no more but this ; that what internal motion i ascribe to the earth , and other the concrete parts of the world , is to be supposed also in every of their parts how small soever ; for what reason is there to think , in case the whole earth have in truth the motion i have ascribed to it , that one part of it taken away , the remaining part should love that motion . if you break a load-stone both parts will retain their vertue , though weakened according to the diminution of their quantity ; i suppose therefore in every small part of the earth , the same kind of motion , which i have supposed in the whole : and so i recede not yet from my basen . a. let it be supposed , and withall , that abundance of earth ( which i see you aim at , ) be drawn up together with the water . what then ? b. then if many pregnant clouds , some ascending and some descending meet together , and make concavities between , and by the pressing out of the air , as i have said before , become ice ; those atomes ( as i may call them ) of earth will be by the straining of the air through the water of the clouds , be left behind , and remain in the cavities of the clouds , and be more in number then for the proportion of the air therein . therefore for want of liberty they must needs justle one another , and become ( as they are more and more streightened of room ) more and more swift , and consequently at last break the ice suddenly and violently , now in one place , and by and by in another ; and make thereby so many claps of thunder , and so many flashes of lightning . for the air recoiling upon our eyes , is that which maketh those flashes to our fancy . a. but i have seen lightning in a very clear evening , when there has been neither thunder nor clouds . b. yes in a clear evening ; because the clouds and the rain were below the horison , perhaps or miles off ; so that you could not see the clouds nor hear the thunder . a. if the clouds be indeed frozen into ice , i shall not wonder if they be sometimes also so scituated , as ( like looking-glasses ) to make us see sometimes three or more suns by refraction and reflection . chap. vii . problems of motion perpendicular , oblique ; of pression and percussion ; reflection and refraction ; attraction and repulsion . if a bullet from a certain point given , be shot against a wall perpendicularly and again from the same point oblique , what will be the proportion of the forces wherewith they urge the wall ? for example , let the wall be a b , a point given e , a gun c e that carries the bullet perpendicularly to f , and another gun d e that carries the like bullet with the same swiftness oblique to g ; in what proportion will their forces be upon the wall ? b. the force of the stroke perpendicular from e to f will be greater then the oblique force from e to g , in the proportion of the line e g to the line e f. a. how can the difference be so much ? can the bullet lose so much of its force in the way from e to g ? b. no we will suppose it loseth nothing of its swiftness . but the cause is , that their swiftness being equal , the one is longer in coming to the wall then the other , in proportion of time , as e g to e f. for though their swiftness be the same ▪ considered in themselves , yet the swiftness of their approach to the wall is greater in e f then in e g , in proportion of the lines themselves . a. when a bullet enters not , but rebounds from the wall , does it make the same angle going off , which it did falling on , as the sun-beams do ? b. if you measure the angles close by the wall there difference will not be ensible ; otherwise it will be great enough , for the motion of the bullet grows continually weaker . but it is not so with the sun-beams which press continually and equally . a. what is the cause of reflection ? when a body can go no further on , it has lost its motion . whence then comes the motion by which it reboundeth ? b. this motion of rebounding or reflecting proceedeth from the resistance . there is a difference to be considered between the reflection of light , and of a bullet , answerable to their different motions , pressing and striking . for the action which makes reflection of light , is the pressure of the air upon the reflecting body , caused by the sun , or other shining body , and is but a contrary endeavour ; as if two men should press with their breasts upon the two ends of a staff , though they did not remove one another , yet they would find in themselves a great disposition to press backward upon whatsoever is behind them , though not a total going out of their places . such is the way of reflecting light. now , when the falling on of the sun-beams is oblique , the action of them is nevertheless perpendicular to the superficies it falls on . and therefore the reflecting body , by resisting , turneth back that motion perpendicularly , as from f to e , but taketh nothing from the force that goes on parallel in the line of e h ; because the motion never presses . and thus of the two motions from f to e , and from e to h is a compounded motion in the line f h , which maketh an angle in b g , equal to the angle f g e. but in percussion ( which is the motion of the bullet against a wall , ) the bullet no sooner goeth off then it loseth of its swiftness , and inclineth to the earth by its weight . so that the angles made in falling on and going off , cannot be equal , unless they be measured close to the point where the stroke is made . a. if a man set a board upright upon its edge , though it may very easily be cast down with a little pressure of ones finger , yet a bullet from a musquet shall not throw it down but go through it . what is the cause of that ? b. in pressing with your finger you spend time to throw it down . for the motion you give to the part you touch is communicated to every other part before it fall . for the whole cannot fall till every part be moved . but the stroke of a bullet is so swift , as it breaks through before the motion of the part it hits can be communicated to all the other parts that must fall with it . a. the stroke of a hammer will drive a nail a great way into a piece of wood on a sudden . what weight laid upon the head of a nail , and in how much time will do the same ? it is a question i have heard propounded amonst naturalists , b. the different manner of the operation of weight from the operation of a stroke , makes it uncalculable . the suddenness of the stroke upon one point of the wood takes away the time of resistance from the rest . therefore the nail enters so far as it does . but the weight not only gives them time , but also augments the resistance ; but how much , and in how much time , is ( i think ) impossible to determine . a. what is tbe difference between reflection and recoiling ? b. any reflection may ( and not unproperly ) be called recoiling ; but not contrariwise every recoiling reflection . reflection is always made by the re-action of a body prest or stricken ; but recoiling not always . the recoiling of a gun is not caused by its own pressing upon the gun-powder , but by the force of the powder it self , inflamed and moved every way alike : a. i had thought it had been by the sudden re-entring of the air after the flame and bullet were gone out . for it is impossible that so much room as is left empty by the discharging of the gun , should be so suddenly filled with the air that entereth at the touch-hole . b. the flame is nothing but the powder it self , which scattered into its smallest parts seems , of greater bulk by much , then in truth it is , because they shine . and as the parts scatter more and more , so still more air gets between them , entring not only at the touch-hole , but also at the mouh of the gun. which two ways being opposite , it will be much too weak to make the gun recoil . a. i have heard that a great gun charged too much or too little , will shoot ( not above , nor below but ) besides the mark ; and charged with one certain charge between both will hit it . b. how that should be i cannot imagine . for when all things in the cause are equal , the effects cannot be unnequal . as soon as fire is given , and before the bullet be out , the gun begins to recoil . if then there be any unevenness or rub in the ground more on one side then on the other , it shall shoot besides the mark , whether too much , or too little , or justly charged ; because if the line wherein the gun recoileth decline , the way of the bullet will also decline to the contrary side of the mark . therefore i can imagine no cause of this event , but either in the ground it recoils on , or in the unequal weight of the parts of the breech . a. how comes refractin ? b. when the action is in a line perpendicular to the superficies of the body wrought upon , there will be no refraction at all . the action will proceed still in the same straight line , whether it be pression as in light , or in percussion as in the shooting of a bullet . but when the pression is oblique , then will the refraction be that way which the nature of the bodies through which the action proceeds shall determin . h. how is light refracted ? b. if is pass through a body of less , into a body of greater resistance , and to the point of the superficies it falleth on , you draw a line perpendicular to the same superficies , the action will proceed not in the same line by which it fell on , but in another line bending toward that perpendiculare . a. what is the reason of that ? b. i told you before , that the falling on worketh only in the perpendicular ; but as soon as the action proceedeth further inward then a meer touch , it worketh partly in the perpendicular , and partly forward , and would proceed in the same line in which it fell on , but for for the greater resistance which now weakneth the motion forward , and makes it to incline towards the perpendicular . a. in transparent bodies it may be so ; but there be bodies through which the light cannot pass at all . b. but the action by which light is made , passeth through all bodies . for this action is pression ; and whatsoever is prest , presseth that which is next behind , and so continually . but the cause why there is no light seen through it , is the uneveness of the parts within , whereby the action is by an infinite number of reflections so diverted and weakned , that before it hath proceeded through , it hath not strength left towork upon the eye strongly enough to produce sight . a. if the body being transparent the action proceed quite through , into a body again of less resistance , as out of glass into the air , which way shall it then proceed in the air ? b. from the point where it goeth forth , draw a perpendicular to the superficies of the glass , the action now freed from the resistance it suffered , will go from that perpendicular , as much as it did before come towards it . a. when a bullet from out of the air entreth into a wall of earth , will that also be refracted towards the perpendicular ? b. if the earth be all of one kind , it will. for the parallel motion , will there also at the first entrance be resisted , which it was not before it entred . a. how then comes a bullet , when shot very obliquely into any broad water , and having entred , yet to rise , again into the air ? b. when a bullet is shot very obliquely , though the motion be never so swift , yet approach downwards to the water is very slow , and when it cometh to it , it casteth up much water before it , which with its weight presseth downwards again , and maketh the water to rise under the bullet with force enough to master the weak motion of the bullet downwards , and to make it rise in such manner as bodies use to rise by reflection . a. by what motion ( seeing you ascribe all effects to motion ) can a load-stone draw iron to it ? b. by the same motion hitherto supposed . but though all the smallest parts of the earth have this motion , yet it is not supposed that their motions are in equal circles ; nor that they keep just time with one another ; nor that they have all the same poles . if they had , all bodies would draw one another alike . for such an agreement of motion , of way , of swiftness , of poles , cannot be maintained without the conjunction of the bodies themselves in the center of their common motion , but by violence . if therefore the iron have but so much of the nature of the load-stone as redily to receive from it the like motion , as one string of a lute doth from another string strained to the same note ( as it is like enough it hath , the load-stone being but one kind of iron ore ) it must needs after that motion received from it , ( unless the greatness of the weight hinder ) come nearer to it , because at distance their motions will differ in time , and oppose each other whereby they will be forced to a common center . if the iron be lifted up from the earth , the motion of the load-stone must be stronger , or the body of it nearer , to overcome the weight ; and then the iron will leap up to the load-stone as as swiftly as from the same distance , it would fall down to the earth ; but if both the stone and the iron be set floating upon the water , the attraction will begin to be manifest at a greater distance , because the hindrance of the weight is in part removed . a. but why does the load-stone if it float on a calm water , never fail to place it self at last in the meridian just north and south . b. not so , just in the meridian , but almost in all places with some variations . but the cause i think is , that the axis of this magnetical motion is parallel to the axis of the ecliptique , which is the axis of the like motion in the earth , and consequently that it cannot freely exercise its natural motion in any other scituation . a. whence may this consent of motion in the load-stone and the earth proceed ? do you think ( as some have written ) that the earth is a great load-stone ? b. dr. gilbert that was the first that wrote any thing of this subject rationally , inclines to that opinion . decartes thought the earth ( excepting this upper crust of a few miles depth ) to be of the same nature with all other stars , and bright . for my part i am content to be ignorant ; but i believe the load stone hath given its virtue by a long habitude in the mine , the vein of it lying in the plain of some of the meridians , or rather of some of the great circles that pass through the poles of the ecliptique , which are the same with the poles of the like motion supposed in the earth . a. if that be true ▪ i need not ask why the filings of iron laid on a load-stone equally distant from its poles will lie parallel to the axis , but one each side incline to the pole that is next it . nor why by drawing a load-ston all a long a needle of iron , the needle will receive the same poles nor why when the load-stone and iron ( or two load-stones ) are put together floating upon water , will fall one of them a stern of the other , that their like parts may look the same way , and their unlike touch , in which action they are commonly said to repel one another . for all this may be deriv'd from the union of their motions . one thing more i desire to know , and that is ; what are those things they call spirits ? i mean ghosts , fairies , hobgoblins , and the like apparitions . b. they are no part of the subject of natural philosophy . a. that which in all ages , and all places is commonly seen ( as those have been , unless a great part of mankind by lyers ) cannot , i think , be supernatural . b. all this that i have hitherto said , though upon better ground than can be had for a discourse of ghosts , you ought to take but for a dream . a. i do so . but there be some dreams more like sense then others . and that which is like sense pleases me as well ( in natural philosophy ) as if it were the very truth . b. i was dreaming also once of these things ; but was weakened by their noise . and they never came into any dream of mine since , unless apparitionrs in dreams and ghoasts be all one . chap. viii . the delphique problem or duplication of the cube . a. have you seen a printed paper sent from paris , containing the duplication of the cube , written in french ? b. yes . it was i that writ it , and sent it thither to be printed , on purpose to see what objections would be made to it by our professors of algebra here . a. then you have also seen the confutations of it by algebra . b. i have seen some of them ; and have one by me . for there was but one that was rightly calculated , and that is it which i have kept . a. your demonstration then is confuted though but by one . b. that does not follow . for though an arithmetical calculation be true in numbers , yet the same may be , or rather must be false , if the units be not constantly the same . a. is their calculation so inconstant , or rather so foolish as you make it ? b. yes . for the same number is sometimes so many lines , sometimes so many plains , and sometimes so many solids ; as you shall plainly see , if you will take the pains to examine first a demonstration i have to prove the said duplication , and after that , the algebrique calculation which is pretended to confute it . and not only that this one is false , but also any other arithmetical account used in geometry , unless the numbers be always so many lines , or always so many superficies , or always many solids . a. let me see the geometrical demonstration . b. there it is : read it . to find a cube double to a cube given . let the side of the cube given be v d. produce v d to a , till a d be double to d v. then make the square of a d , namely a b c d. divide a b and c d in the middle at e and f. draw e f. draw also a c cutting e f in i. then in the sides b c and a d take b r and a s each of them equal to a i or i c. lastly , divide s d in the middle at t , and upon the center t , with the distance t v , describe a semi-circle cutting a d in y , and d c in x. i say the cube of d x is double to the cube of d v. for the three lines d y , d x , d v are in continual proportion . and cntinuing the semi-circle v x y till it cut the line r s drawn and produced in z , the line s z , will be equal to d x. and drawing x z it will pass through t. and the four lines t v , t x , t y and t z will be equal . and therefore joyning y x and y z , the figure v x y z will be a rectangle . produce c d to p so as d p be equal to a d. now if y z produced fall on p , there will be three rectangle equiangled triangles , d p y , d y x , and d x v ; and consequently four continual proportionals , d p , d y , d x ▪ and d v , whereof d x is the least of the means . and therefore the cube of d x will be double to the cube of d v. a. that 's true ; and the cube of d y will be double to the cube of d x ; and the cube of d p double to the cube of d y. but that y z produced , falls upon p , is the thing they deny , and which you ought to demonstrate . b. if y z produced fall not on p , then draw p y , and from v let fall a perpendicular upon p y , suppose at u. divide p v in the midst at a , and joyn a u ; which done a u will be equal to a v or a p. for because v u p is a right angle , the point u will be in the semi-circle whereof p v is the diameter . therefore drawing v r , the angle u v r will be a right angle . a. why so ? b. because t v and t y are equal ; and t d , t sequal ; s v will also be equal to d v. and because d p and r s are equal and parallel , r y will be equal and parallel to p v. and therefore v r and p y that joyn them will be equal and parallel . and the angles p u v , r v u will be alternate , and consequently equal . but p u v is a right angle ; therefore also r v u will be a right angle . a. hitherto all is evident . proceed . b. from the point y raise a perpendicular cutting v r wheresoever in t , and then ( because p y and v r are parallel ) the angle y t v will be a right angle . and the figure u y t v a rectangle , and u t equal to y v. but y v is equal to z x ; and therefore z x is equal to u t. and u t must pass through the point t ( for the diameters of any rectangle , divide each other in the middle ) therefore z and u are the same point , and x and t the same point . therefore y z produced falls upon p. and d x is the lesser of the two means between a d and d v. and the cube of d x double to the cube of d v which was to be demostraten . a i cannot imagine what fault there can be in this demonstration , and yet there is one thing which seems a little strange to me . and 't is this . you take b r , which is half the diagonal , and which is the sine of degrees , and which is also the mean proportional between the two extreams . and yet you bring none of these proprieties into your demonstration . so that though you argue from the construction , yet you do not argue from the cause . and this perhaps your adversaries will object ( at least ) against the art of you demonstratieon , or enqure by what luck you pitched upon half the diagonal for your foundation . b. i see you let nothing pass . but for answer you must know , that if a man argue from the negative of the truth , though he know not that it is the truth which is denyed , yet he will fall at last , after many consequences , into one absurdity or another . for though false do often produce truth , yet it produces also absurdity , as it hath done here . but truth produceth nothing but truth . therefore in demonstrations that tend to absurdity , it is no good logick to require all along the operation of the cause . a. have you drawn from hence no corollaries ? b. no. i leave that for others that will ; unless you take this for a corollary , that , what arithmetical calculation soever contradicts it , is false . a. let me see now the algebrical demonstration against it . b. here it is . let a b or a d be equal to then d f or d v is equal to and b r or a s is equal to the square root of and a v equal to want the square root of . the cube of a b is equal to the cube of d y is equal to want the square root of that is almost equal to for want the square root of is equal to therefore d y is a little less then the greater of the two means between ad and dv . a. there is i see some little difference between this arithmetical aud your geometrical demonstration . and though it be insensible , yet if his calculation be true , yours must needs be false , which i am sure cannot be . b. his calculation is so true , that there is never a proposition in it false , till he come to the conclusion , that the cube of d y. is equal to , want the square root of . but that , and the rest , is false . a. i shall easily see that a d. is certainly , whereof d v. is , and a v. is certainly , whereof d v. is . b. right . a. and b r. is without doubt the square root of . b. why , what is ? a. , is the line a d. as being double to d v. which is . b. and so , the line b r. is the square root of the line a d. a. out upon it it , it 's absurd . why do you grant it to be true in arithmetick ? b. in arithmetick the numbers consist of so many units ; and are never considered there as nothings . and therefore every one line has some latitude , and if you allow to bi . the semi-diagonal the same latitude you do to ab . or to br . you will quickly see the square of half the diagonal to be equal to twice the square of half ab . a. well , but then your demonstration is not confuted ; for the point y , will have latitude enough to take in that little difference which is between the root of and the root of . this putting off an vuit sometimes for one line , sometimes for one square , must needs marr the reckoning . again he says the cube of ab . is equal to . but seeing ab . is , the cube of ab . must be just equal to four of its own sides ; so that the vnit which was before sometimes a line , sometimes a square , is now a cube . b. it can be no otherwise when you so apply arithmetick to geometry , as to mumber the lines of a plain , or the plains of a cube . a. in the next place , i find that the cube of dy . is equal to , want the square root of . what is that ? lines , or squares , or cubes ? b. cubes , cubes of dv . a. then if you add to cubes of dv . the square root of , the sum will be cubes of dv . and if you add to the cube of dy . the same root of , the sum will be the cube of dy . plus the square root of . and these two sums must be equal . b. they must so . a. but the square root of , being a line , adds nothing to a cube ; therefore the cube alone of dy . which he says is equal almost to . cubes of dv . is equal to cubes of the same dv . b. all these impossibilities do necessarily follow the confounding of arithmetick and geometry . a. i pray you let me see the operation by which the cube of dy . ( that is the cube of , want the root of , ) is found equal to , want the square root of . a detection of the absurd use of arithmetick as it is now applyed to geometry . b. here it is . — r. . — r. . — r. ✚ : — r. — r. ✚ . — r. . — r. ✚ — r. . — r. ✚ — r. — r. ✚ — r. . a. why for two roots of do you put the root of . b. because roots of is equal to one root of times , which is . a. next we have , that the root of multiplyed into , makes the root of . how is that true ? b. does it not make roots of ? and is not br . the root of , and br equal to the diagonal ? and is not the diagonal the root of a square equal to squares of dv ? a. 't is true . but here the root of is put for the cube of the root of . can a line be equal to a cube ? b. no. but here we are in arithmetick again , and is a cubique number . a. how does the root of multiplyed into the root of make ? b. because it makes the root of times , that is to say the root of which is . a. how does roots of make the root of ? b. because it makes the root of squares of , that is the root of . a. how does roots of make the root of ? b. because it makes the root of times , that is of . a. for the total sum i see and which make . therefore the root of together with the root of ● and of , which are to be deducted from , ought to be equal to the root of . b. so they are . for multiplyed by makes of which the double root is — and and added together make — . therefore the root of , added to the root of makes the root of — again into is . the double root whereof is — . the sum of and added together is — . the sum of and is , and the root , the root of — . a. i see the calculation in numbers is right , though false in lines . the reason whereof can be no other then some difference between multiplying numbers into lines or plains , and multiplying lines into the same lines or plains . b. the difference is manifest . for when you multiply a number into lines , the product is lines ; as the number multiplyed into lines is no more then lines times told . but if you multiply lines into lines you make plains , and if you multiply lines into plains you make solid bodies . in geometry there are but three dimensions , length , superficies , and body . in arithmetick there is but one , and that is number or length which you will. and though there be some numbers called plain , others solid , others plano-solid , others square , others cubique , others square-square , others quadrato-cubique , others cubi-cubique &c. yet are all these but one dimension , namely number , or a file of things numbered . a. but seeing this way of calculation by numbers is so apparently false , what is the reason this calculation came so near the truth . b. it is because in arithmetick units are not nothings , and therefore have breadth . and therefore many lines set together make a superficies though their breadth be insensible . and the greater the number is into which you divide your line , the less sensible will be your errour . a. archimedes , to find a streight line equal to the circumferrence of a circle , used this may of extracting roots . and 't is the way also by which the table of sines , secants aud tangents have been calculated , are they all cut ? b. as for archimedes , there is no man that does more admire him then i do . but there is no man that cannot err. his reasoning is good . but he ads all other geometricans before and after him , have had two principles that cross one another when they are applyed to one and the same science . one is , that a point is no part of a line which is true in geometry , where a part of a line when it is called a point , is not reckoned ; another is , that a unit is part of a number which is also true ; but when they reckon by arethmetick in geometry , there a unit is somtimes part of a line , sometimes a part of a square , and sometimes part of a cube . as for the table of sines , secants and tangents , i am not the first that find fault with them . yet i deny not but they are true enough for the reckoning of acres in a map of land. a. what a deal of labour has been lost by them that being professors of geometry have read nothing else to their auditors but such stuff as this you have here seen . and some of them have written great books of it in strange characters , such as in troublesome times , a man would suspect to be a cypher . b. i think you have seen enough to satisfie you , that what i have written heretofore concerning the quadrature of the circle , and of other figures made in imitation of the parabola , has not been yet confuted . a. i see you have wrested out of the hands of our antagonists this weapon of algebra , so as they can never make use of it again . which i consider as a thing of much more consequence to the science of geometry , then either of the duplication of the cube , or the finding of two mean proportionals , or the quadrature of a circle , or all these problems put together . finis . books written by this author , and printed for william crooke . de mirabilibus pecci , in quarto latin , in octavo in english and lantin . three papers to the royal society against dr. wallis . lumathematica . prima partis doctrinae wallisianae de motu censura brevis . resetum geometricum , sive propositiones aliquot frustra antehac tentatae . principia & poblemata aliquot geometrica , ante desperata , nunc breviter explicata & demonstrata . quadratura circuli cubatio sphaere duplicatio cubi breviter demonstrata . consideration on his loyalty , reputation , religion and manners ; by himself . de principio & ratione geometri . the travels of vlises translated from homer . epistol . ad dr. wood. the translation of all homers works into english. the epitome of the civil wars of enland from to . aristotles rhetorick translated into english by him , with his own rhetorick to it . a dialogue betwixt a student in the common-laws of england , and a philosopher in which is set forth the errors in some practise . a narration of heresie and the punnishment thereof . ten dialogues of natural philosophy . a poem in latin of his life . — idem the same in english. his life written in latin , part by himself and the rest by dr. r. b. wherein is contained the most material parts of his life . seven philosophical problems , and two propositions of geometry . with an apology for himself , and his writings . dedicated to the king , in the year . naturall philosophie reformed by divine light, or, a synopsis of physicks by j.a. comenius ... ; with a briefe appendix touching the diseases of the body, mind, and soul, with their generall remedies, by the same author. physicae ad lumen divinum reformatae synopsis. english comenius, johann amos, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing c estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) naturall philosophie reformed by divine light, or, a synopsis of physicks by j.a. comenius ... ; with a briefe appendix touching the diseases of the body, mind, and soul, with their generall remedies, by the same author. physicae ad lumen divinum reformatae synopsis. english comenius, johann amos, - . [ ], p. printed by robert and william leybourn for thomas pierrepont ..., london : . translation of: physicae ad lumen divinum reformatae synopsis. reproduction of original in bodleian library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . science -- early works to . - tcp assigned for keying and markup - aptara keyed and coded from proquest page images - melanie sanders sampled and proofread - melanie sanders text and markup reviewed and edited - pfs batch review (qc) and xml conversion naturall philosophie reformed by divine light : or , a synopsis of physicks : by j. a. comenius : exposed to the censure of those that are lovers of learning , and desire to be taught of god. being a view of the world in generall , and of the particular creatures therein conteined ; grounded upon scripture principles . with a briefe appendix touching the diseases of the body , mind , and soul ; with their generall remedies . by the same author . london : printed by robert and william leybourn , for thomas pierrepont , at the sun in pauls church-yard , mdcli . to the truly studious of wisdome , from christ the fountain of wisdome , greeting . jacobus acontius , a most excellent man , offended at the evill disposition of our scribling age wished that it might be provided , that none should write and publish any thing , unless it were some new thing ; which should both be of his own observation , and might make for the glory of god , and the aedification of the church , and from whence so much fruit might be hoped , that what time is bestowed on the reading of it , the readers could not bestow it better elswhere : that so nothing might be done which was already done , but what was yet to be done . for few writers ( says hee ) bring any thing of their own : but onely steal , things and words , of which they make books , &c. which they know to be most truly spoken , who are to peruse that farrago of books , wherewith we are yearly little less then overwhelmed . for if you look on the titles , you shall have them always new and very specious : if on the thing , it is always the same boiled over and over above a thousand times , and coleworts crammed in , even to nauseating . and though something of new observation be offered , yet to what purpose is it , that whole books should therefore be written , and those new things found out so buried in things ordinary , that either a man hath no mind to enquire , what of new observation is in them , or cannot do it without tediousness of spirit and loss of time . but it is not my business to inveigh against this disorder in many words . i come now to declare why i my self come out in publick . and i wil lay it open in a word i bring something new , and different from the common way of philosophie : and i bring it so , as that i hope , it will be without any ones hinderance or molestation , as conteining in a very few leaves , matters of very great moment . and i bring it to satisfie the desires of others this way . for whereas i had the year last past , given a proof of my philologicall endeavours , janua linguarum reserata , ( or a seminary of arts and languages ) which was courteously received , and that with applause , and approved almost by all mens verdict , ( as severall letters , dated either to my self or my friends , touching that matter do testifie , ) some ( of the number of those , who at this time bend their desires , thoughts and dedevours , to rectifie the method of studies ) began to solicit mee , to put out my philosophicall works , or at least to desire a communication of my conceptions , especially in physicks . having no other minde therefore , but to bring something for mine owne part that may be profitable , if it may be : or else that others may have occasion by me , to bring better matters ; i purposed with my self to expose to the light , this same synopsis of physicks , lately dictated in this schoole , that publick censure might be made of this also , as well as of my former work. which that it might be , it seemed meet to give some further intimation of the occasion and scope of our undertaking , to those that wil offer themselves to be our censors . after that the calamitous lot of exile had thrust mee , who was by calling a divine , back to the services of the school , wherein i was desirous to beare my self , not slightly , but so as that i might discharg the trust committed to me ; it chanced that i hapned , among other things , upon ludovicus vives his books , detradendis disciplinis . in these when i had found most wholesome counsels , for the repairing of philosophie , and the whole course of studies , i began extreamly to grieve , that a man of so piercing a wit , after he noted so many most evident errours , had not put to his hand to make those rough things smooth , but the judgment of one touching this excellent writer , that vives saw better what was not then what was , made mee to consider , that it is usuall with the wisdome of god to communicate things by degrees . yet i thought with my self that others should take this as an occasion to labour to designe one certain and infallible way among so many deviations discovered unto them : which i wondred that men were so backward to essay for full a hundred years . ( for i knew not whether any one had gone about it . ) but it hapned , that a certain learned man , to whom i communicated these complaints of mine in a more familiar manner , shew'd mee a book call'd , prodromus philosophiae instaurandae by thomas campanella an italian : which i read over with incredible joy , and being inflamed with an exceeding great hope of new light , i greedily turn'd through his realis philosophia epilogistica ( for so hee calls it ) set forth in foure books , as also the books de rerum sensu , where ever i could get them . whereby i found my desires in some sort satisfied , but not throughout . for his very foundation , that all things were made up of two contrary principles onely , offended me ( for i was already most fully perswaded of the number of three principles out of the divine book of genesis : and and i remember out of hugo grotius , disputing against the manichees , that of two things fighting one with the other , destruction might follow , but an ordinate construction could never follow . ) and besides i observed that campanella himself was not very certaine of his own hypotheses : as one that began to waver in his assertions towards the positions of galilaeus touching the earths mobility , and yet to call them in doubt himself : as it is evident ●enough in his apologie for galilaeus . but when i chanced afterwards upon a piece of sir francis bacon baron of verulam , chancellour of england , entituled inst aur atio magna ( an admirable work , and which i look upon no otherwise , then as a most bright beam of a new age of philosophers now arising ) i understood that in some particulars also of campanella , such solid demonstrations , as the truth of things requires , were wanting . yet it grieved me again , that i saw most noble verulam present us indeed with a true key of nature , but not open the secrets of nature , onely shewing us by a few examples , how they were to be opened ; and leave the rest to depend on observations and inductions continued for severall ages . yet i saw nevertheless , that my hopes were not quite left in suspense : in as much as i perceived my minde so enlightned by the light which it received from those severall sparks , now grown welnigh to a torch , that some great secrets of nature , and very obscure places of scripture , ( the reason of which i knew not before ) were now plain , as it were of their own accord , to the exceeding great content of my mind . for now with those , that have lighted upon a more sound way of philosophie in this age , i saw and rested in it ; i that the onely true , genuine and plain way of philosophie is to fetch all things from sense , reason and scripture . ii that the peripatetick philosophie is not onely defective in many parts , and many ways intricate , full of turnings and windings , and partly also erroneous , so that it is not onely unprofitable for christians , but also ( without correction and perfection hurtfull . iii that philosophie may be reformed and perfected , by an harmonicall reduction of all things that are and are made , to sense reason and scripture , with so much evidence and certainty ( in all such things as are of most concernment , and have any necessity ) that any mortall man seeing may see , and feeling may feel , the truth scattered every where . of all and every of which observations , least we should seem to have dreamed somewhat , there will be some thing to be said more at large . and for the first we make three principles of philosophy , with campanella , and his happy interpreter tobie adams , sense , reason and scripture : but so joyntly , that whosoever would not be left in ignorāce or doubt , should rest on no one of these without the others , otherwise it wil be a most ready precipice into errors . for sense , though it make an immediate impression upon us of the truth imprinted upon things : yet because it is very often confounded , either by reason of the multitude of things in a manner infinite , and the strange complications of formes : or else wearied and tired , sometimes with the distance of the objects , and so consequently dazeled and deceived . reason must of necessity be imployed , which may conclude alike of like things , and contrarily of contrary things , by observing their proportion , and so supply the defect of sense , and correct its errours . but then because many things are remote both from sense and reason ( which we cannot in any sort attein unto by sense , nor yet by reason firmly enough ) we are indepted to the grace of god , that he hath by his word revealed unto us even some secrets which concern us to know . therefore if any one desire the true knowledg of things , these three principl●s of knowing must of force be conjoyned . otherwise , he that will follow the guidance of sense onely , will never be wiser then the common sort ; nor be able to imagine the moon lesse then a starre ; the sun greater then the earth ; and that again sphaericall , and every way habitable . on the contrary if a man contemplate on abstract things and consult onely with reason without the testimony of sense , he will be rapt away with meer phantasines , and create himself a new world : like the platonicall and aristotelicall , &c. lastly , they that heed the scripture onely , and hearken neither to sense nor reason are either carried away beyond the world ( by the sublimity of their conceptions ; ) or else involve things they understand not with the colliers faith ; or following the letter , propound unto themselves things , though never so absurd and superstitious , to be believed ; as papists do in that most absurd transubstantion of theirs , &c. so then the principles of knowing , must be conjoyned , that divine revelation may afford us belief ; reason , understanding , sense , certainty . and they must be used in this order ( in naturall things i say ) as that we begin with sense , and end in revelation ( as it were the setting to the seal of god : ) for by this order every subsequent degree will receive receive from the antecedent , both evidence and also certainty , and emendation . for as there is nothing in the understanding which was not first in the sense : so there is nothing in the belief , which not first in the understanding . for he that believes , must know what is fit to be believed . hence the scripture frequently invites us to hear , see , tast , consider ; and affirmes that faith too comes by hearing . i said certainty too . for by how much the neerer reason is to sense ( that is by how many the more experiments of the senses it may be demonstrated ) it is so much the more reall : and on the contrary again , the further it recedes from sense , by so much the more vain speculation and naked imagination it hath . but by how much the neerer divine revelation may be reduced to understanding , and the testimonies of experience , so much the more strength it findes . i said further , that the precedent degrees were corrected by the subsequent : and so it is . for where sense fails or mistakes , it is supplied and corrected by reason : and reason by revelation . for example , when the sense judgeth the moon to be bigger then saturn , or an oare to be broken under the water , &c. reason rectifies it by certain documents of experience . so when reason hath gathered any thing falsely of things invisible , it is amended by divine revelation . yet that emendation is not violent , and with the destruction of the precedent principle : but gentle , so that that very thing which is corrected , acknowledgeth , and admits it of its own accord , and with joy , and soon brings something of its own , whereby the same corrected truth may become more apparent . for example , reason brings nothing to correct sense , whereof it is not soon ascertained by sundry experiments , and affirmes it self , that so it is , ( as that an oare is not broken under water , the touch teacheth : as also the sight it self , looking on it after it is drawn out . ) faith holds out nothing , which is contrary and repugnant to reason , ( though it bring that which is beyond and above reason : ) but all things such as reason not onely yields being overcome by authority , but also finds of a truth to be in things , and so seeks and finds out some thing of its own , which may serve to confirme and illustrate the same truth . therefore let it be taken for true , that sense is not onely the fountain of knowledge , but also of certainty , in naturall things : but that the understanding is the organ not onely of knowledge , but also of certainty in revealed things . let us come then to the purpose . some deny , that holy scripture is to be drawn to philosophie , because it teacheth not the speculation of outward things , but the way of eternall life , i confess , that the scripture was given by inspiration of god , to teach , reprove , correct , and instruct in righteousness : that the man of god may be perfect , throughly furnished unto all good works . ( tim. . ) i confess , i say , that this is the ultimate end of the scripture . yet who knows not , that there are for the most part more ends of one thing ? even in humane things , much more in divine , where the wisdom of our adored god hath wholly wound up it self , with an artifice scarce to be found out of us . truly , if wee finde that artifice all over nature , ( and so it is ) that every creature , and part of a creature , and part of a part , serves for severall uses : i see no reason why we should deprive the book of god of this character of the highest wisdome . but i see reason why we ought to determine , that most sufficient complements of all things , whereunto sense and reason were insufficient ( and yet wee were concerned to know them ) are extant in that most holy book . for did not god bring man into the school of the world , to contemplate his manifold wisdome ? did not hee command him to behold his invisible things by these things that are seen ? ( rom. . v. . ) surely this must be acknowledged to be the end both of making the world and placeing man therein . now it is cleere through all nature , that , to whatsoever end god hath ordained any thing , he hath conferred means upon it to be tein it . hee hath therefore conferred means upon man to contemplate his wondrous things : which as wee must acknowledge that they are sense and reason , so we must needs acknowledge that they are not every where sufficicient . for our senses leave us in the knowledge of eternall things , and those things which are placed quite out of sight , and done when we are not present . but where sense fails , reason fails also : being that this is nothing but an universall knowledge of things , gathered from particulars acts of sense ; that this or that is , or is done , either so or so . when as therefore both sense and reason doe very ordinarily fail us , shall we believe , that the most gracious father of lights , would not supply this defect some other way ? his most liberall and in every respect approved bounty towards us , will not permit us to suspect that . but if god have some way or other provided for us , let it be shewen what it is , or where it is to be sought for , if not in that sacred volume of oracles ? and i pray , was it in vain , or onely in respect of our eternall salvation , that god said of his law. this is your wisdome and understanding in the sight of the nations , which shall heare all these statutes and say . surely this is a wise and understanding people . ( deut. . . ) or did david boast in vain ? i have more under standing then all my teachers ; because thy testimonies are my meditations ( psal. . . ) or the sonne of sirach say in vain : the word of god most high is the fountain of wisdom ? ( eccles. . . or was it in vain that salomon call'd god , the guide unto wisdome , and the corrector of the wise ? wisd. . . ) see here a correctour ! but how doth he correct , but by dashing over our vain cogitation with his word ? and to what purpose , i pray is all that is frequently mētion'd concerning the beginning of the world and the order of the creation , and properties of the creatures , if the parent of nature , who is also the dictatour of the scriptures , meant to teach us nothing of nature ? they say it is to this end , that we may learn to know and admire , love and fear the maker of all things . right : but how the maker without his work ? does not any one so much the more admire and praise the ingenuity of the painter , if he be excellent , by how much the better he understands the art of painting ? surely yes . a superficiall knowledge will never raise either love or admiration . and then i demand , those things , which wee meet with in the scriptures concerning the creatures ( by similitudes also drawn thence ) are they true or false ? if true ( for who can determine otherwise without blasphemie ) why may we not conferre them with those things that are manifest by sense & reason ? that so we may finde out that harmony of truth , which is in things , and in the mouth of the author of things ? truly , if the words of the wise are as goades and nails fastened : ( as salomon testifies , eccles. . . ) what shall we think of the words of the all-wise god ? but this , that though they raise us up with another end , and by the by , yet they contein nothing but most solid truth and all manner of-wisedome . in vain therefore may some one say : i finde no mention in the scriptures , much less precepts of grammar , logicke , mathematicks , physicks , &c. for there is as much distance betwixt divine writings and humane , as betwixt god himself and man. man that is limited with time , place and objects , at one time and in one place can do but one thing : but god that is aeternall , omnipresent , and omniscient , at once sees , rules and governs all things , always and every where . and the same character do their writings retein on either part . humane writings do some one thing with expresse endeavour , handling one object in one place , and that in such a way as is most pleasing to mans understanding : but divine writings like an universal treasury of wisdome stay not upon one particular matter , ( unlesse it be in things pertaining to theologie ) but contein variety of matter under severall sayings . whence a divine , a moralist , a politician , a housholder , a philosopher , a philologer , &c. may take out every of them , what each hath use of . and this breadth & depth of the scripture is its prerogative before humane writings , that so it may be in truth an inexhaustible fountain of all wisdome . for whatsoever matter is to be handled , the scripture affords always , either a rule , or some sayings or examples : as john henrie alsted ( sometimes my honoured master ) shews in his triumphus biblicus , and much more might be discovered by a very accurate diligence : which that so it is , for a good part of it , shall appear also in these our physicall meditations . rightly therefore said cassiodorus : the scripture is an heavenly school , wherein we learn whatsoever we are either to learn or to be ignorant of . and piously t. lydiat : it is most absurd , that heathen philosophers should seek for the principles of all arts in one homers posie , and that we christians should not do the same in the oracles of god , which are a most plentifull and most clear fountain of wisdome . ( about the end of his physiological disquisition . ) those most christian philosophers are therefore deservedly to be praised , who have endeavoured to render unto god the parent of things that praise that is due unto him , franc. valesius , lambert danaeus , levinus lemnius , thomas lydiat , conradus as●acus , otto casmannus ; who have not doubted to asseverate , that the seeds of true philosophy are conteined in the holy book of the bible , and to derive their maximes of philosophy from thence ( though with different successe . ) let it stand therefore , that philososophy is lame without divine revelation . whence wee have this consequence , that aristotle is not to be tolerated in christian schools , as the onely master of philosophie : but that we should be free philosophers , to follow that which our senses , reason , and scripture dictate . for what ? are not we placed as wel as they in natures garden ? why then do we not cast about our eyes , nosthrils and ears as well as they ? why should we learn the works of nature of any other master , rather then of these ? why do we not , i say , turn over the living book of the world instead of dead papers ? wherein we may contemplate more things , and with greater delight and profit then any one can tell us . if we have any where need of an interpretour the maker of nature , as we have said , is the best interpretour of himself . if a monitour or suggestour , we have more and better then aristotle , experience ( of the various and occult maeanders of nature ) being multiplyed in the processe of so many ages . for as all humane things get up to perfection from rude beginnings , so philosophy hath had its grouths too . in aristotles age it was scarce out of its infancy : in the ages that followed after , ( especially in ours ) it was so increased stil with new observations , that the aristotelick tenets savour of obscurity & uncertainty in cōparison of these , nay , they hold out open falsities . be it then ( writes rod. goclenius to nic. taurellus ) that nature hath shewed all the acutenesse of humane ingenuity in aristotle ; let aristotle be a man that hath deserved well of all humane wisdome beyond and above all other mortall men besides ; let him be the father and captain of our wisdome ; let him be the supream dictatour of wisdome , the generalissimo of philosophers , the eagle of the philosophicall kingdome , wisdome and praise of literature ; let him be the hercules , the prince , the tribunall of truth ; let him be the deity of philosophers ; let him be lastly a man greater then all praise , and above all calumny ; which titles julius scaliger sets him out with : yet this miracle of nature is not the rule of truth , seeing that hee hath not every where traced truths footsteps . thus goclenius . now hee that will may see campanella and verulamius , ( for it may suffice , to have shewed these hercules , who have happily put to their hands to the subduing of monsters , and cleansing augias stables ; and to have opposed them to those , whom the authority of aristotles vainly swelling philosophy holds bewitched : ) and feel how farre aristotles assertions are often from the truth , and this is the cause why it seems convenient , that aristotle with all his heathenish train should be excluded from the sacred philosophy of christians ; least they should any more entangle the truth in errours , and involve and obscure those things with intricate disputations , which are of themselves plain by the lamp of the word of god , and of sound reason . for is it not very absurd , that christians , who are trained up in the true knowledge of the true god , and taught by his holy voice , concerning the originall causes , end , and manne of subsistence of all things visible and invisible ; to whom also the very mysteries of aeternity are revealed ; whom the anointing of god teacheth al● things ; to whom christ hath imparted his mind ( john . v. . cor . . ) that they , i say , should see for the truth of things amongst th● heathen , that are destitute of all the●e and have no other helps , but those of reason , and of the senses , which are common to us with them ? is it so indeed that there is not a god in israel , that we go to enquire of the gods of ekron ? is the light of hierusalem so put out , that we must needs borrow lamps at athens ? it is well known that origen was the man that first of all joyned heathen philosophy with christian religion : with no ill intent perhaps , but sure it is with very bad event . the good mans purpose without doubt was to put some externall splendour upon christian religion , as then contemned by reason of its simplicity , that so christians might be well appointed to buckle with the gentile philosophers at their own weapons . but whither or no came this perswasion from him , that hath called us out of darknesse into his marvellous light , and commanded us to beware of vain philosophy after the tradition of men , after the rudiments of the world , and not after christ. ( gal. . . pet , . . colos. . . ) and indeed the most sad estate of the church a little after shews what fruit we had in coupling aristotle what christ ; when all was ful of the noise of disputations , ( for slippery quaestions , and an itching desire of controversie is the very soul of peripateticisme ) and haeresie sprung out of haeresie , till at length the fumes of humane opinions had so quite darkned the brightnesse of the divine wisdom , that all things degenerated into antichristianisme . where in forging articles of faith , and ordaining rules of life , aristotle had an aequall share with christ , that i may not say he had the sole dictatourship : of which thing our school divinity will give us a very cleer sight . if origen then a man of so sublime a wit , in vain attempted to piece out christian religion with that same heathen philosophy ; and thomas scotus nor no man else had any better successe , why then do we tolerate it ? why do we not slip our wits out of those snares ? why do we not throw away those spectacles which present us with fancies instead of things ? some are afraid , least , if they should let go peripatetick philosophy , they should have none at all . as if when hagar were cast out , there would have been none to bless abraham with issue ! or that the israelites would have been sterved with hunger , when they . had left the aegyptian flesh pots ; or that moses must needs have grown blockish , when he was out of the company of the wise men of memphis ! nay rather , that promised grace will come at length , at length that heavenly manna will rain down , at length we shall be truly 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 taught of god , when turning away our ears from humane opinions , we shall hearken to god alone speaking by nature , and by his word . and then how solid , easie , and delightfull will all things be ! when as the whole course of philosophy will not consist in opinions but in truth . but greater care was to be had of method : that all things should be delivered to the learners in such a way , that they may finde knowledge to flow into them , not to be stuft in ; always beginning with those things that are best known , and ending in things no lesse known then they . for why should we think that impossible in physicks , which is so excellently atchieved in mathematicks ? whereall demonstrations ( n. w. ) are brought to the very sight : and all is so contrived together of things that go before and are better known ( always beginning with such common things that it is taedious to the unskilfull to heare them ) in such an order , as that which is in the middest is never skipt over , nor place , given to that which is more unknown , whence it comes to passe , that you must of necessity assent as well to that which is last , as to that which is first . and truly there is reason to wonder why the like hath not been yet assayed in metaphysicks , physicks , and theologie , ( for ethicks and politicks concern more contingent things . ) i am not ignorant that there is more evidence in numbers , measures and weights , then in qualities , by which nature puts forth its strength after a hidden manner : yet i will not say that there is greater certainty in them , seeing that all things are done alike not without highest reason , in a continued order , and as it were by an aeternall law . and yet in mathematicks all things are not alike plain , yet they are assayed sundry wayes till they can be reduced to 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or very sight , as i said before , and delivered scientifically . for he sayes nothing in philosophicall matters that proves nothing : and he proves nothing that doth not so demonstrate it , that you cannot contradict it . and now i beseech you let this be our businesse , that the schools may cease to perswade , and begin to demonstrate : cease to dispute and begin to speculate : cease lastly , to believe , and begin to know . for that aristotellicall maxim , discentem oportet credere , a learner must believe is as tyrannicall as dangerous ; and that same pythagorean 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ipse dixit . let no man be compell'd to swear to his masters words , but let the things themselves constrain the intellect : nor let a master have any more credit given him , then hee can demonstrate in very deed , that hee is to have . for in a free common-wealth there ought to be no kings , but dukes or generalls ; no dictators , but consuls . and those that profess the art of instructing men , are the fathers of men , not the carvers of statues . o when shall we see that day ! that all things which ought to be known shall offer themselves so to a mans understanding , that there wil be nothing but what may be understood for the very cleerness of it , nothing call'd in doubt for certainty : the truth of things making such an impression upon the senses with its light . for hee doth not see truly , who must yet be perswaded by arguments to make him believe that hee sees : as wee have been hither to dealt with for the best part . i could not choose , because i seemed to see light in the light of god , but assay calling god to my aid , to reduce these new hypotheses of naturall things into a new method , and dictate them to the schollers of this school . and thence sprang this , which i now offer , representing a draught of the lineaments of some new , ( and as i hope truly christian ) philosophie . not that i would crosse the design of great verulam ( who thought it the best way to abstein from axiomes and method , till full inductions could be made , of all and every thing throughout all nature : ) but to make an experiment in the mean time , whether more light might be let into our minds by this means to observe the secrets of nature the more easily , that so praise might be perfected to god out of the very mouth of infants , and confusion prepared for the gain saying enemie ; as david having comprised the summe of physicks in a short hymne for the use of the unlearned ) speaks . ( psal. . ) i have entituled it a synopsis of physicks reformed by divine light : because philosophy is here guided by the lamp of divine scripture , and all our assertions are brought to the attestation of the senses and reason , with as much evidence as could be possible . now both those come under the name of divine light . for as david said , thy word is alanthorne unto my feet : so said salomon the spirit or mind of a man is the candle of the lord searching all things . ( psalm . . and proverbs . . if any one object : that these things here delivered , are not yet of that certainty or evidence , as to be preferred before aristotles so long received doctrine ; i will answer , that is not my drift at present : but onely i propound this as an example , that a truer way of philosophie may be set out , by the guidance of god , the light of reason , and the testimonie of sense , if philosophers would labour more after god and the truth , then after aristotle and opinion . in the mean time , these should be the more acceptable , and had in more reverent esteem of us , if it were for nothing but this , that they are taken from the oracles of god , and aime at a more abundant knowledg of god. for my part truly i had rather ( in that mind i now am : and that it may so continue , strengthen me , ô god ) i had rather i say erre , having god for my guide , then having aristotle : that is , i had rather follow the voice of god , though not throughly understood yet , so i follow it , then be carried away from the sacred testimonies of my god , to the devices of the brain of man. i confesse my self , that something more were to be desired here yet , to that rule of certainty and evidence which i spake of before : yet because i trust that these things may be brought to a fuller 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 [ exactnesse ] by reiterated meditations , ( of mine own or some others , ) i doubted not to follow the counsell of great acontius : if thou hast made any rare observation , sayes he , which never any one before made ( whither the thing be a new invention , or some new way of former inventions ) although much be wanting as yet , which is above thy strength , neverthelesse if thou shouldest not make it publick , it would argue either too much cowardize , or too much haughtinesse of thy mind , and however that thou art no lover of the common wealth . and why should not these things be accounted as new inventions ; that ternarie of principles so clearly demonstrated from scripture , reason , and sense ? why not that admirable scale of substances , by a septenarie gradation ? why not the doctrine of spirits ( as well separate as incorporate : ) of motions also and qualities , laid down more accurately and plainly then ever before , & letting in a quite new light into the knowledge of natur all things ? to say nothing of smaller matters scattered all over the book . every of which in particular though i dare not defend tooth and nail , for some things perhaps are still the reliques of common tradition : and others it may be , not yet sufficiently established upon the foundations w ch we have laid down ) yet i am perswaded that they are the groundworks of unmoved truth , and avail much to the more exact observation of particular things . and that i may speak in a word , i hope there is so much light in this method of physicks here delivered , that very little place is left to doubts and disputations : so that it makes something towards the taking away the controversies of authours , the opinions of all ( whatsoever of truth either aristotle hath ; or galen , the chymicks , campanella and verulamius do reasonably alledge against him ) being reduced to an harmony ; which may be made plain by the example of the principles of which they make bodies to consist , ( which aristotle would have to be the four elements ; the syagyricks salt , sulfur and ☿ . nay more , that by this means a gate is opened in a new kinde of way , not onely to the understanding of arts and humane inventions , but also to multiply them : which could never be , unless the foundations of truth were found . perhaps i speak more , then the reader will think he finds in my writings . but if he saw but the streams ( the delineation of that pansophia christiana , which wee have in hand ) that are derived , from this fountain , as also from that of our didacticks and metaphysicks , hee would not hold it vainly spoken . but because those are not yet brought to light , i set down this as a law for these that are : if any thing be not sufficiently deduced from sense , reason , and scripture ; if any thing cohere not harmoniously enough with the rest ; if any thing be not evident enough with its own perspicuity , let it be taken as not said at all . which law standing in force it may be lawful for my self & all others , both to doubt always , and every where whether every thing be so as it is delivered to be : and also to enquire why it is , as it is found to be ; by which two courses , that the lowest foundations of truth , will in time be discovered no body needs to doubt . therefore let none of vs seeke after any thing else , but how the truth may best be maintained on all hands which if it happen not to be on our side , and that we are deceived with appearances of truth , ( as it is very usuall in humane affaires , ) i beseech all those that are more sharp-sighted , for the love of truth courteously to shew us our way , which we have lost , and where our demonstrations come not together . but if these savour of truth something neer , that then they would not disdain to joyn their endevours with ours for the illustration thereof : that all of us being the children of truth may compose and sing hymnes of prayse together to god the father of truth . thou therefore o christ the fathers glory bright , of this great world the onely light ; on us some beams of light bestow , that are thy servants , thee to know . amen , lord make me to see ! here indeed thy externall light shining upon , and internall informing thy creatures , but there in [ in heaven ] aeternall and uncreated ! amen , amen . and so christian readers farewel . j. a. c. march the th . . imprimatur john downame . a table of the heads of this book . prolegomena , of the nature and use of physick . i an idea of the world to be created and created . pag. ii of the principles of the world , matter , spirit and light. iii of the motion of things . iv of the qualities of things . v of the mutation of things . vi of the elements . vii of vapours . viii of concretes ix of plants . x of living creatures . xi of man. xii of angels . an appendix to physicks , of the diseases of the body , mind and soul , aad their remedies . errata . page . for softness read saltness , p. . for softness r. saltness , p. . line . for run r. noisome , p. . l. . for veins r. reins , ibid. l. dele by . prolegomena . touching the nature , foundation and use of physick . i physick is the scientiall knowledge of naturall ▪ things . ii that thing is naturall , which is by nature , not by art for whatsoever this visible world hath , comes all , either from nature or from art those things are from nature which god brought forth in the beginning , or w ch are to this very time begotten : by a virtue implanted in things , as , the heavens , the earth , the sea , rivers , mountains , stones , metals , hearbs , living creatures , &c. those things are from art which men have shaped , by putting a new form upon natural things ; as , cities , houses , ponds , channels , statues , coines , garments , books , &c. that is by the work of mans ingenuity and hands . physicks have nothing to do with these things ; these are put over to the arts . now seeing that nature is before art : ye that art imitates nothing but nature , for as much as it doth nothing but by the strength of nature : it necessarily follows , that nature is to be laid for a foundation to arts , and that nature must first be knowne by those that are studious of arts , what things , and by what vertue it operates every where ▪ for when this is known , the secrets of all arts open of their own accord , without this in arts and prudentials all wil be blinde , dumbe , and maimed : therefore physick is so necessary to be premised before the mathematical , and logical , and also the prudentiall arts , that they who do otherwise , may be thought to build castles in the air . iii the nature of things is , the law of being born and of dying , of operating and of ceasing , which god the workmaster hath laid upon all things that are . for all things are born and die : all things operate somewhat , and all things cease again : in an order and manner proper to every creature ▪ which order and manner being that it is with most excellent reason , could not be disposed , but by the supream wisdome , inasmuch as it is found constantly to be imposed by way of a law upon things ▪ now it took the name of nature from the first degree of mutation of every thing , which is , to be borne . iv the knowledge of nature is to be obtein'd by searching into nature it self . by searching i say . for no one should spend his time in physicks , to that end , that he might have his mind taken up with anothers conceits ; but that he may put forward himself to the through and intimate knowledg of things , otherwise the intellect will not be illustrated with the nature of things , but obumbrated with the speculation of phantasms in naturall things , therefore we are to seek for guides who may make us scholers , not of themselves , but of nature , and exhibite unto us not their own fond reasons , but nature . v to search nature , is to contemplate , how , and wherefore , every thing in nature is done . to contemplate i say . for as we do not see the sun , but by looking on the sun : so we do not learn nature , but by looking into nature ; which is that the scripture counsels us . ask the beasts , and they shall teach thee , and the fouls of the aire , and they shall tell thee , or talk with the earth , and it shall answer thee , and the fishes of the sea shall declare unto thee . ( job . . ) therefore the learners of naturall philosophy , cannot be more happily and easily instructed , then if they be taught by ocular demonstration , wheresoever it is to be had : i say to contemplate every thing , that so we may sift out the reasons and causes of all things every where . for it is certain that nature doth nothing in vain , even in things of least moment , yea sometimes in the very least things much wisdome lies stored up . and which is more , we cannot attain to the knowledg of great things , but by the knowledg of lesser things , which the following aphorisme will teach us . vi nature unfolds her self in the least things , and wraps up her self in the greatest things . that is , in the more excellent creatures many things are wound up and woven together with such an occult artifice , that neither the beginning nor the endings of actions and accidents can easily be discerned , but in all courser creatures , all things are clearly manifest , which is the cause why the nature of compounds cannot be knowne , unlesse the nature of simples be first known : so consequently we are to begin with these speculations , and to proceed by degrees from simpler things to the more compound : which very order we shall see that the creator himself observed , in producing and twisting together the nature of things . vii wee are to studie naturall phylosophie by the guide of sense , and light of the scripture . for sense is the beginning not onely of knowledge , but of certainty and wisdome ; for as there is nothing in the intellect which was not first in the sense , so if there be any thing obscurely or doubtfully in the intellect , we are to have recourse to the sense for evidence and certainty . but wheresoever sense or reason faileth , ( as in things remote either in place or time ) we are indebted to the grace of god , that he hath deigned to reveale many things unto us exceeding sense and reason . for example , the first production of the world , and the constitution of things invisible . he that neglecteth either of these principles is easily intangled in errours : for by how much the more of imagination any thing hath , by so much the more vanitie it hath , and is the more remote from the truth : again , by how much the lesse any thing participates of revealed wisdome , by so much the lesse it partakes of the truth . and such for the most part is the philosophy of the gentiles , and therefore vain and barren , we will follow the guidance of moses , ( who described the generation of the world by the command of god : ) yet always heedfully observing the attestation of the senses , and of reason . for wisely doth lud. vives ( as we have set down under the title of this book ) recall christians from the lamp of the gentiles , which yeilds an obscure and maligne light , to that torch of the sun , which christ the light of the world brought into the world , attributing much wit indeed , but little profit to the inventions of aristotle . nay further campanella and verulamius most christian philosophers ( that are acquainted with that way of philosophy from sense and scripture ) have demonstrated , that all aristotles doctrines are nothing but a nurserie of disputations , ( that is , of obscurities , haesitancies , contradictions , strifes , and wranglings ) and fighting hood-winckt , and that they hinder rather then advance our meditation of things , and withall have afforded us a light , whereat we may kindle more clear torches of inquiring out the truth . following vvhose footsteps ( yet laying strong foundations from the scripture ) vve vvill dresse out a little theatre of nature , not for disputation , but for speculation ; and vve vvill go through nature silently , yet not vvithout our eyes , and that again according to the counsel of great vives : here is no need of disputations , ( saith he ) but of a silent contemplation of nature : the scholars shal enquire and ask rather then contend : if any be more slow they wil need more ful commonstration not disputation , and a little after , again i say , here is no need of wrangling but of looking on , so this study wil be the delight of the rich , and a refreshing of the mind to those that deal either in publike or in private affairs : for when shal we easily find any other delight of the senses , to be compared with this , either in the greatness or in the variety , or in the continuance of it ; for when we bestow our labour upon this contemplation , wee need not seek for any other recreation , nor desire sawce for this meat , the walk it self , and the quiet contemplation is both a school and a master , as that which always affords something , which thou mayest admire , wherein thou mayest delight , which may increase thy knowledge . therefore let us resolve upon this , vve that vievv naturall things , to rest upon no other authority besides that of the work-master of nature , and of nature her self ( as she holds forth her self to be touched and felt ) the scriptures , sense and reason , shal be our guides , wìtnesses and dictators , to the testimonies of vvhich he that assents not , shevvs himselfe very foolish and vain . chap. i. an idea of the world to be created and created . the eternall deitie , our god that is to be adored , after the infinite glories which hee enjoyes in his immense eternity , was of his exceeding goodnesse propense to communicate himselfe out of himself ; and by his exceeding wisdome saw that his invisible things might be expressed by certain visible images ; and to execute that , had his omnipotencie at hand , he decreed not to envie entitie to those things , wherein he might be expressed , and wherein his power , wisdome and goodness might be revealed : therefore he produced intelligent creatures , by whom he might be known & praised angels and men : both after his own image : but the first pure minds , the other clothed with bodies for whom he built a dwelling place , and as it were a school of wisdome , this universall world with other creatures of inferiour degree almost infinite : all and every of which , cry out after their manner , hee made us , and not wee our selves . now then we go about to unfold in what order so great a work proceeded , and with what art all things were contrived , and with what strength they are held together , yet by his guiding who alone is able to testifie of himself and of his works ; for thus , says he , by his secretary moses . gen. . i in the beginning god created the heaven , ( v. . ) that is , the heaven of heavens with the angels : whom as morning stars first produced , he made spectatours of the rest of his works . ( joh. . v. . ) ii and the earth ) that is this visible world , which notwithstanding he did not finish in the same moment , therefore it is said . iii and the earth was void , & without form , and darknesse was upon the face of the deep . v. . that is , the matter of this world was first produced , a certain chaos without form and darke , like a black smoake arising out of the bottomlesse pit of nihilitie , by the beck of the almighty , and this was matter , the first principle of this visible wo●ld . iv and the spirit of god moved upon the water , ) that is a certaine strength was introduced by the spirit or breath of god into that same darke , and of it selfe confused matter , whereby it began to stirre . hereby then is understood the second principle of the world , that is , the spirit of life diffused throughout , whereof the universal world is hitherto ful ; which insinuating it selfe every where through all the parts of the matter , cherishes and rules it , and produces every creature , introducing into every one it s own form , but being that this work-master had need of fire to soften and to prepare the matter , variously for various uses , god produced it . for , v god said let there be light and there was light , ver . . ) this is described , as the third principle of the world , meerly active , whereby the matter was made visible and divisible into forms , the light , i say , perfecting all things which are , and are made in the world , therefore it is added . vi and god saw the light that it was good , ver . ) that is , he saw that all things would now proceed in order . for that light being produced in a great masse , began presently to display its threefold virtue ( of illuminating , moving it selfe , and heating , ) and by turning about the world , to heat and rarifie the matter , and so to divide it . for hence followed first of all from the brightnesse of that light the difference of nights and days . vii he divided the light from darkness , and called the light day , and the darknesse he called night , and the evening and morning were the first day , ver . ● . ) that is , that light when it had turn'd it self round , & compassed the world , with that motion made day and night . the second effect of light was from heat , namely , that which way soever it pass'd , it rarified and purified the matter , but it condensed it on both sides , upward and downward . whence came the division of the elements , this moses expresses in these words . viii and god said , let there be a firmament , that it may divide betwixt the wa●er above and the waters below , ver . . ) god said , that is , he ordained how it should be . let there be a firmament , that is , let that light stretch forth the matter , and let the thicker part of the matter melting and flying from the light thereof , make waters on this side and on that . above , as they are the term of the visible world ; but below , as they are a matter apt to produce other creatures , under which the earth as thick dregs came together . that was done the second day . xi therefore god said , let the waters be gathered together under heaven into one place , and let the dry land appear . and it was so ; and god called the dry land , earth , and the gathering together of the waters he called seas , and he saw that it was good . ver . , . ) and so on the third day , there came the foure greatest bodies of the world out of the matter already produced , aether , ( that is , the firmament or heaven ) aire , water and earth ; all as yet void of lesser creatures . therefore said god. x let the earth bud forth the green herb , and trees bearing seed or fruit every one according to his kinde ver . . ) this was done the same third day , when as now the heat of coelestiall light having wrought more effectually began to beget fat vapours on the earth , whereinto that living spirit of the world insinuating it self , began to cause plants to grow up in various formes , according as it pleased the creator . this is the truest original and manner of generation of plants hitherto , that they are form'd by the spirit with the help of heat . but as the heavens did not always equally effuse the same heat , but according to the various form of the world , one while more midly , another while more strongly ; the fourth day god disposed that same light of heaven , otherwise then hitherto it had been , namely , forming from that one great masse thereof divers lucid globes , greater and lesser , which ( being called stars ) he placed here and there in the firmament higher and lower , with an unequall motion , to distinguish the times , and this moses describes v. , , &c. thus . xi and god said , let there be light made in the firmament of heaven , that they may divide the day and the night , and may be for signes , and for seasons , and for days , and for years , that they may shine in the firmament , and enlighten the earth , therefore god made two great lights , and the starres , &c. ) this done , then after , all the face of the world began to appear beautifull , and the heat of heaven more temperate , began to temper the matter of inferiour things together , after a new manner ; so that the spirit of life now began to form more perfect creatures , namely moving plants , which we call animals , of which moses thus . xii god said also , let the waters bring forth creeping things , having a soul of life , and flying things upon the earth , &c. v. . ) the waters were first commanded to produce living creatures , because it is a softer element then earth : first reptiles , as earth-wormes , and other worms , &c. ) because they are as it were the rudiment of nature , also swiming things , and flying things , that is , fishes and birds , animals of a more light compaction ; that was done on the fift day with a most goodly spectacle to the angels ; but on the sixth day , god commanded earthly animals to come forth , namely of a more solid structure , which was presently done , when the spirit of the world distributed it self variously through the matter of the clay : for thus moses . xiii god said , let the earth produce creatures , having life according to their kind , beasts , and serpents , and beasts of the field , and it was s● . v. . ) so now the heaven of heavens had for inhabitants , the angels ; the visible heaven , the starres , the air birds , the water fishes , the earth beasts , there was yet a ruler wanting for these inferiour things , namely , a rationall creature , or an angel visibly clothed , for whose sake those visible things were produced . therefore at the last when god was to produce him , he is said by moses to have taken counsel ; in these words . xiv then god said , let us make man after our own image , and likenesse , who may rule over the fishes of the sea , and the fouls of the air , and beasts , and all the earth , &c. therefore he created man out of the dust of the earth , and breathed in his face the breath of life , &c. v. . and cap. . v. . ) so man was made , like to the other living creatures by a contemperation of matter , spirit and light ; and to god and the angels , through the inspiration of the mind , a most exquisite summarie of the world , and thus the structure of the universe ought to proceed , so as to begin with the most simple creature , and end in that which is most compound but both of them rationall ; that it might appear , that god created these onely for himself , but all the intermediate for these . lastly , that all things are from god , and for god , flow out from him , and reflow to him . but that all these things might continue in their essence , as they were disposed by the wisdome of god , he put into every thing a virtue , which they call nature , to conserve themselves , in their effence , yea , & to multiply , whence the continuation of the creatures unto this very day , and this moses intimated , adding touching animals . xv and god said , increase and multiply , v. . ) by the virtue of which command and words , let there be made , let it produce , let it put forth , &c. things are made and endure hitherto , and would remain ( if god would ) without end unto aeternity . gods omnipotency concurring no longer immediately unto particular things , ( as before ) but nature it self , always spreading forth her vertue through all things . which thing derogates nothing from the providence of god , nay rather it renders his great power , wisdome , & goodnes , more illustrate . for it comes from his great goodness , that the greatest and the least things are so disposed to their ends , that nothing can be , or be made in vain ; from his wisdome , that such an industry is put into nature to dispose all things to their e●ds , so that it never happens to erre , unlesse it be hindred : lastly , from his power , that such an immutable durability can be put into the universe , through such a changeable mutabilitie of particulars , so that the world is as it were aeternall . therefore the veins of the strength , artifice and order of this nature must be more throughly searched ; that those things which we have here in few words hinted out of moses , may be more illustrated by the constant test●mony of scripture , reason and senses , and a way made to observe one thing out of another . an appendix to the first chapter . we have said that it may be gathered out of those words of moses . in the beginning god created the heaven : that the invisible world was the beginning of the works of god , that is the heaven of heavens with the angels . now that by this heaven is to be understood the heaven of heavens , and the invisible , or angelicall world appeares plain . i. out of scripture , which mentions the heaven of heavens every where ; but their production no where , unlesse it be here . moses testifies that the invisible heavens were stretched out the second day , and the fourth day adorned with starres , therefore another heaven must necessarily be understood in this place ; namely a heaven that was finished in the same moment , for that the particle autem inferres , hee created the heavens and the earth ; terra autem , but the earth was without form , &c. iii this reason evinces the same , those things which are made by god are made in order , now an orderly processe in operation , is this , that a progresse be made from more simple things , to compound things , therefore as the most compound creature man was last produced ; so the most simple and immateriall creatures , ( heaven and the angels ) first of all . iii and what would we have more ? god himself testifies expresly ; that when he made the earth , the angels stood by him as spectators , for so saith he to job ; where wast thou when i founded the earth , when the morning starres sang together , and all the sonnes of god shouted . ( job . . , . ) calling the angels morning starres , because they were a spirituall beam , and that newly risen : sonnes of god , because they were made after the image of god. therefore when we hear , that the earth was founded the first day , it must needs be that the angels were produced before the earth : and if the angels , then certainly the dwellings of the angels , the heaven of heavens ; and that in full perfection , with all their hosts , as it were in one moment , aud this is the cause why moses speaks no more of that heaven , but descends to the forming of the earth , that is the visible world : ( how the creator took unto himself six dayes to digest it ) as we will also now descend . chap. ii. of the visible principles of the world , matter , spirit and light . we have seene , god shewing us , how the world arose out of the abysse of nihilitie ; let us now see how it standeth , that so by seeing we may learn to see , and by feeling to feel , the very truth of things . and here are three principles of visible things held out unto us , matter , spirit , and light , that they were produced the first day , as three great but rude masses , and out of those variously wrought , came forth various kinds of creatures , therefore we must enquire further , whether these three principles of all bodies , have a true being , and be yet existent . least any errour be perhaps committed at the very entrance , by any negligence whatsoever , but now seeing that no more doubts of matter , and light , this onely comes to be prooved , that by that spirit which hovered upon the face of the waters , a certain universall spirit of the world , is to be understood , which puts life and vigour into all things created , for the newnesse of this opinion in physicks , and the interpretation of that place by divines with one consent of the person of the holy spirit , give occasion of doubting . but chry●ostome , ( as aslacus cites him ) and danaeus acknowledgeth , that in this place a created spirit , which is as it were the soul of the world , is more rightly to be understood ; and it is proved strongly . i by scripture , which testifieth that a certain vertue was infused by god through the whole world , susteining and quickening all things , and operating all things in all things ; which he calleth both a spirit and a soul , and sometimes the spirit of god , sometimes the spirit of the creatures . for example ( psal. . v. . . ) david saith thus ; when thou receivest their spirit , ( that is the spirit of living creatures , and of plants ) they die , and return to their dust : but when thou sendest forth thy spirit ( that is the spirit of god , ) again , they are recreated , and the face of the earth is renewed , but job ( . . ) says thus ; as long as my soul shall be in me , and the spirit of god in my nostrils ; see the soul of man , and the spirit of god are put for the same ! which place compared with the saying of elihu , the spirit of god hath made me , and the breath of the omnipotent hath put life into me . ( c. . v. . ) opens the true meaning of moses ; namely that the spirit of god stirring upon the waters , produced the spirit or soul of the world , which puts life into all living things . now that this is disposed through all things , appears out of ezechiel : where god promising the spirit of life unto the dry bones , ( ezech. . v. , . ) which he cals his spirit , bids it to come from the four winds ( v. ) therefore augustine , ( lib. imperf . sup . gen. ad lit . ) and basil ( in hexamero ) call this spirit , the soule of the world . and aristotle ( as sennertus testifies ) says that the spirit of life is a living and genitall essence diffused through all things but the testimony of elihu , is most observable , who speaks thus . who hath placed the whole world ? if he ( namely god ) should set his heart upon it , and should gather unto himself the spirit thereof , and the breath thereof ( or : his spirit and his breath : for the hebrew affix is rendred both ways ) all flesh would die together , and man would return unto dust . job . v. , . so , if god should take his spirit out of the world , every living thing would die . by reason and sense , it is certainly evident , that herbs and animals spring out of a humide matter , even without seed . but whence had these life , i pray you , but from that diffused soul of the world ? wee finde by experience , that bread , wine and water , yea aire , are vitall to those that feed upon them , but whence have they that vital force , i pray you , if not from this diffused soule ? but now if a certaine spirit be diffused in that manner through all things , it follows necessarily , that it was created in the begining in its whole masse , even as the matter & the light were first produced , in that its great and undigested masse : so that there was no need that any thing should be created afterwards , but be compounded of those three , and distinguished with forms . which god intimated , in esay . v. . where declaring himself the creator of all things , he divides them into three parts , namely , into the heavens , ( that is light the earth , ( that is matter ) and a quickning spirit , and just so in zachary . v. . let us therefore hereafter beware so great an absurdity , ( that i may not say blasphemy ) as to put the person of the holy ghost amongst the creatures . now there may three reasons of this thing be given , why moses called that quickning spirit , produced in the beginning , the spirit of god. namely , that it is taken in that sense , wherein els-where it is spoken of ●he mountains of god , ( psal. . v. . ) and trees of god ( psal. . v. . ) and ninive was called a citie of god : that is , by reason of their greatness and dignity . . because it was produced immediatly by god ; not as now it is , when that spirit passeth from one subject to another . because it was a peculiar act of the holy ghost . for the analogie of our faith teacheth us to believe , that the production of the matter out of nothing , is a work of gods omnipotencie , and is attributed to the father ; that the production of light ( by which the world received splendour and order ) is a work of wisdome attributed to the son , ( john . v. , . ) and lastly , that the virtue infused into the creatures is a work of his goodnesse , which is attributed to the holy ghost . ( psal. . v . ) and so must that place ( psal. . v. & . ) be altogether understood , ( for it will not bear any other sense ) he spake and they were made ; he commanded , and they came forth : the heavens were established by the word of god , and all the virtue of them by the spirit of his mouth also wee must note , ( gen. . v. , , . ) that three words are added to the three principles , he created , he said , and he moved himself ; that they may be signs of his absolute power , of his word , and of his spirit . also we must note this , that in both those places the holy ghost with his work is placed in the midst ; ( as also in esay . v. . ) because he is the spirit , the love , and the mutuall bond of both , but this we speak after the manner of men let it stand therefore for certain , that all the principles were created the first day , every one in its masse ; and that all things were afterwards composed out of them , which may be declared to children ( for their more full understanding ) by a similitude thus : an apothecary or confectioner being to make odoriferous balls , takes sugar in stead of matter ; rose-water , or syrrup , or some other sweet liquour for tincture or conditure ; last of all taking some of this lumpe thus made , hee imprints certain shapes upon his work . so also god first prepared his matter : then tempered it with a living spirit ; then brought light into it , which by its heat and motion might mix and temper both together and bring it to certain forms . also even as a mechanick must have matter , and two hands to work withall ; the one hand , to hold ; and the other to work with : so in the framing of the world , there was need , first of matter , then of a spirit to frame the matter , and lastly of light , or heat to inactuate the matter under the hand of the spirit . and what need many words ? we see in every stone , hearb , and living creature : first a certain quantity of matter ; secondly , a certain inward virtue , whereby it is generated , it groweth , it spreads abroad its savour , and its odour and its healing virtue ; thirdly , a form or a certain disposition of parts with divers changes , which come from the heat working within . for , matter is a principle meerly passive , light meerly active , spirit indifferent , for in respect of the matter it is active ; in respect of the light , passive . the difinitions of the principles . matter , is a corpulent substance , of it self rude and dark , constituting bodies . spirit , is a subtile substance , of it self living , invisible and insensible , dwelling and growing in bodies . light , is a substance of it self visible , and moveable , lucid , penetrating the matter , and preparing it to receive the spirits , and so forming out the bodies . therefore by how much the more matter , any thing hath it hath somuch y e more dulnes , obscurity & immobility : as the earth . vigour and durability : as an angell . form , & mobility : as the sun. spirit , light , note also ; that matter , is the first entitie in the world ' ; spirit , the first living thing ; light , the first moving thing ; so that every body in the world is of the matter , by the light , in the spirit : which he would have to be his image , from whom , by whom , in whom are all things , blessed for evermore , amen . rom. . v. . of the nature of matter . truly said one ; no diligence can be too much in searchingout the beginning of things . for when the principles are rightly set down ; an infinite number of conclusions will follow of their own accord , and the science wil encrease it self in infinitum ; which the creation of things doth also shew . for god having produced the principles the first day , and wrought them together with most excellent skil , made afterward so great variety of things to proceed from them , that both men and angels may be astonished . therefore let us not thinke over much , to frame our thoughts yet of all the principles of the world apart . let the following aphorisms be of the matter . i the first matter of the world , was a vapour or a fume . for what means that description of moses else ? when he calls it earth , waters , the deep , darkness , a thing void , and without form ? and it appears also by reason . for seeing that the lesser bodies of the world , clouds , water , stones , metals , and all things growing on the earth are made of vapours coagulated ( as shall appeare most evidently hereafter : ) why not the whole world also ? certainly the matter of the whole can be nothing else , but that which is found to be the matter of the parts . ii the first matter of the world , was a chaos of dispersed atomes , cohering in no part thereof . this is proved by reason , for if they had cohered in any sort , they had had form : but they had not ; for it was tohu vabohu , a thing without form and void . by sense , which satisfies , that the elements are turned unto atomes . for what is dust , but earth reduced into atomes ? what is vapour , but water resolved into more subtile parts ? the air it self , what is it but a most small comminution of drops of water , and unperceiveable by sense ? yea , all bodies are found to consist of most extream small parts , as trees , barke , flesh , skins , and membranes , of most slender strings or threds ; but bones , stones , metals , of smal dust made up together , into which they may be resolved again . and this shews also , that those threds or haires , are of atomes , as it were glued together , that when they are dried they may be pouldred . wherefore the whole world is nothing but dust , coagulated with various glutinous matters into such or such a form . by scripture for the aeternall wisdom it self testifies , that the beginning of the world was dust . ( prov. . v. . ) out of which foundation many places of scripture wil be better understood : ( as gen. . v. . ) dust thou art , and into dust thou shalt return . for , behold , man was made of the mud of the earth ! yet god being angry for sin , threatens something more , then returning to dust , namely utmost resolution , into the very utmost dust , of which the mud of the earth it self was made : and wee see it to be truly so , that a man is dissolved not onely into earth , but into all the elements , ( especially those that perish by fire ) and is at last scattered into very atomes . read and understand , what is said ( job . v. . ) item . v. . esay . v. . psal. . v. . ) therefore , democritus erred not altogether , in making atomes the matter of the world : but hee erred in that hee believed , that they were aeternall , that they went together into forms by adventure , that they cohere of themselves : by reason that he was ignorant of that which the wisdom of god hath revealed unto us , that the atomes were conglutinated into a mass , by the infusion of the spirit of life , and began to be distinguished into forms , by the comming in of the light . iii god produced so great a mass of this matter , as might sussice to fill the created abysse . for with the beginning of the heaven and the earth , that vast space was presently produced , wherein the heaven and the earth were to be placed , which place moses cals the abysse , which no creature can passe through by reason of its depth and vastness . now the aphorism tels us , that all this was filled up with that confused fume , lest wee should imagine any vacuum . iv the matter is of it self invisible , and therefore dark , for darkness is seen after the same manner when the eyes are shut , as when they are open ; that is , they are not seen at all . and this is it , which moses says : and darkness was upon the face of the abysse . v the matter is of it self without form yet it is apt to be extended , contracted , divided , united , and to receive every form and figure , as wax is to receive every seal . for we have shewed that all the bodies of the world are made of these atomes , and are resolved into them , therefore they are nothing else but the matter clothed with severall forms . which the chymicks demonstrate to the eye , reducing some dust one while into liquour , another while into a vapour , another while into a stone , &c. vi the matter is aeternall in its duration through all forms , so that nothing of it can perish . for in very deed , from the making of the world untill now , not so much as one crum of matter hath perished , nor one increased . for in that bodies are generated , and do perish that is nothing else , but a transmutation of forms in the same matter , as when vapour is made of water , of that vapour a cloud , of the cloud rain , and of the rain drunk in by the roots of plants an hearb , &c. vii the principall virtue of the matter of the world is , are indissoluble cohaerence every where , so that it can endure to be discontinued in no part , and a vacant space to be left . notwithstanding perhaps this virtue is not from the matter , but from the spirit affused : of which in the chapter following . vii from this matter , the whole world is materiall and corporeall , and is so called . for all the bodies of the world , even the most subtle , and the most lightsome , are nothing but form , partly coagulated , partly refined . now after what manner it is coagulated or refined , shall appear in that which follows . of the nature of the spirit , or soule of the world. the spirit of the world , is life it self infused into the world , to operate all things in all . for whatsoever any treature doth or suffers , it doth or suffers it by virtue of this spirit . for it is given to it . i to inhabite the matter . for as in the beginning it moved it self upon the waters , so yet it is not extant , but in the matter ; especially in a liquid and subtile matter . whence in the body of a living creature , those most subtile , sanguine vapours , and as it were flames , which are the charriot of life , are called spirits . and chymicks , extracting a spirit out of herbs , metals , stones like a little water , call it the quintessence , because it is a more subtile substance than all the four elements . but not water it self , as it is water , but that living virtue of the creature , out of which it is extracted , inhabiting in it . which being that it cannot be altogether separated from the matter , is preserved in that subtile form of matter . for how fast the spirit inhaeres in the matter , shall be taught about the end . ( hap . . . ii to move or agitate it self through the whole matter to preserve it . hence it is , that no vacuum can be in the world . for all bodies , even the most subtile , ( as water , air , the skie ) being indued with this spirit , delight in contiguity and continuity . for as a living creature will not be cut , so also water , air , yea the world it self ; by reason of that universall spirit , uniting all things in it , which also when a separation is made ( as in the wounds of living creatures , in the cutting of the water , in the parting of the air may be seen ) makes the matter close again . . that every creature putrifies , when that spirit is taken away , ( as if you extract the spirit of wine out of wine , or suffer the spirit to evaporate out of an hearb , &c. ) but is preserved , yea made better , if the spirit be preserved . for example ; wine kept in any solid vessel under the earth , or water , though it be an years ; grows still the richer : the spirit stirring and moving it self in it , and by that meanes , still moulding the matter more and more , and more and more purifying it from crudities . iii to keep the particular ideas or forms of things . for one & the same spirit of the universe , is afterwards diduced into many particularities , by the comand of god ; so that there is one spirit of water , another spirit of earth , another of metals , another of plants , another of living creatures , &c. and then in every kind again severall species . now then that of the seed of wheat , there springs not a bean , much lesse , a walnut , or a bird , &c. is from the spirit of the wheat , which being included in the seed , formeth it self 〈◊〉 body according to its nature . from the sam● spirit is the custody of the bounds of nature for example ; that a horse grows not to the bignesse of a mountain , nor stays at the smalnesse of a cat . iv to form it self bodies , for the use of future operations . for example , the spirit of a dog being included in its seed , when it begins to form the young , doth not form it wings , or 〈◊〉 or hands , &c. because it needeth not those members : but four feet , and other members , in such sort , as they are fit for that use , to which they are intended . because some dogs are for pleasure , others to keep the house , or flocks , others for hunting ; and that either for hares , or wild bores , or water foul , &c. ( namely , according as the creator mingled the spirit of living creatures , that they should have sympathy or antipathy one with another ) every ones own spirit doth form it a body fit for its end . whence from the sight of the creatures onely , the use of every one may be gathered , as the learned think ; because every creature heareth its signature about it . of the nature of light . i the first light was nothing else but brightnesse , or a great flame , sent into the dark matter to make it visible and divisible into form . for in the primitive language , light and fire are of the same name 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , whence also comes the latine word vro . and verily the light of heaven , doth really both shine and burn , or heat . ii god put into the light a threefold vertue : of spreading it self every way , and illuminating all things . of moving the matter with it being taken hold of , by burning and inflaming . . of heating , and thereby rarifying and attenuating the matter . all these things our fire doth also : because it is nothing else , but light , kindled in the inferiour matter . iii. but when as that light could not extend his motion upwards and downwards , ( for it would have found a term forthwith ) it moved it self , and doth still move in a round : whence came the beginning of dayes . iv and because the matter rarified above heat being raised by the motion of the light , the grosser par●s of the matter were compelled to fall downward , and to conglobate themselves in the middest of the vniverse : which was the beginning of the earth and water . v the light therefore by this its threefold vertue , light , motion , and heat ) introduced contrariety into the world. for darknesse was opposite to light ; rest , to motion ; cold , to heat : whence came other contraries besides , moist and dry , thin and thick , heavy and light , &c. of which c. . vi from the light therefor is the disposition and adorning of the whole world. for the light is the onely fountain both of visibility , and of motion , and of heat ▪ take light out of the world , and all things will return into a chaos . for if all things lose their colours and their formes , in the night when the sun is absent ; and living creatures and plants die in winter , by reason of the suns operation being not strong enough , and the earth and the water do nothing but freeze : what do you think would be , if the luminaries of heaven , were quite extinguished ? therefore all things in the visible world throughout , are , and are made , of the matter , in the spirit , but by the fire or light . chap. iii. of the motion of things . the principles of things being constituted , we are to see the common accidents of things : which are motion , quality , and mutation . for our of the congresse of the principles if the world , came first motion ; out of motion , came quality : and out of quality again , came various mutations of things : which three are hitherto in all created things , as it shall appear . i motion is an accident of a body , whereby it is transferred from place to place . the doctrine of naturall motions , how many they are , and how they are made , is the key to the understanding of all naturall actions : and therefore most diligently to be observed . ii motion was given to things , for generation , action , and time . for generation : for nothing could be ●gotten without composition : nor composed without comming together : nor come together without motion . for actions : because there could be none without motion for time : that it might be the measure of the duration of things . for take the sun and the starres out of the world , nothing can be known , what , where , when : all things will be blind , dumb , deaf . iii motion is either simple or compound . iv simple motion is either of spirit , or of light , or of matter . v the motion of the spirit is called agitation , whereby the spirit agitates if self in the matter seeking to inform it . for the living spirit would not be living , if it should cease to agitate it self , and strive to subdue the matter in any sort whatsoever . this motion is the beginning of the generation , and corruption of things . for the spirit in every thing ( in flesh , an apple , a grain , wood , &c. ) doth by agitating it self , soften the parts , that it may either receive new life , or it may fly out , and the thing purrifie . vi the motion of the light is called diffusion , whereby the light and the heat diffuse themselves into all the parts . for fire , were not fire , nor heat , hear , if it should cease to diffuse it self , and liquifie the matter and from this motion of the fire , all the motion of the matter draws its originall . as the experience of the senses testifies . for grosse and cold things , as wood , a stone , ice , &c. want motion of themselves , which notwithstanding when fire is put to them , they forthwith obtein , as it may be demonstrated to the eye . let there be a kettle full of water , put wood underneath it ; behold all is quiet ! but kindle the wood , you shall presently see motion : first in the wood , flame , smoak , and starting asunder the coals : by and by in the water , first evaporating , afterwards turning it self round , at length , boyling and galloping . but remove away the fire again , all the motion will cease again by little and little . so in a living body ( an animall ) take away heat , forthwith not onely motion , but also mobility will cease , the members waxing stiffe . furthermore , although there be divers motions in things , yet the originall is every where the same , heat or fire : which being included in the world is moved circularly : being kindled in the air , as it darts it self forth , this way or that way , as the matter is disposed , or the wind sits ; included in a living creature , as the strength of the phantasie forceth it this way or that way . vii the motion of the matter is eightfold of expansion , contraction , aggregation , sympathie , continuitie , impulsion , libration and libertie . whereof the first two are immediately from the fire , the four following from some other bodies ; the two last from it self , but by the mediation of the spirit of the universe . which if it seems harsh , will soon appear plain by examples . viii the motion of expansion is , that whereby the matter , being rarified with heat , dilate sits self of its own accord , seeking larger room . for it is not possible that the matter being rarified , should be conteined in the same space : but one part thrusts another , that they may stretch forth themselves , and gather themselves into a greater sphear . you shall see an example , if you drop a few drops of water into a hogs bladder , and having tied the neck thereof , lay it over a furnace , for the bladder will be stretched out , and will swell : because the water being turned into vapour , by the heat seeks more room . ix the motion of contraction is , that whereby the matter is contracted , betaking it self into a narrower space by condensation . for example ; if you lay the foresaid bladder from the furnace into a cold place ; for the vapour will return to water , and the swelling of the bladder will fall . or if you put a thong into the fire , you shall see it wil be wrinkled and contracted because the softer parts being extracted by the fire ; the rest must needs be contracted : from the same reason also , the chinks and gapings of timber and of the earth come . x the motion of aggregation i● , when a body is carried to its connaturals . for example , our flame goes upward , a stone goes downward : for the flame perceives , that its connaturals ( that is subtile bodies ) are above ; a stone that its ( that is heavy things ) are here below . note well , that they cōmonly call this motion naturall , who are ignorant of the rest . but though it appear most in sight , and seem to be most strong and immutable , yet indeed it is weak enough ; because it gives place to all the rest that follow , and puts not forth it self , but when they cease : which will of it self appear , to one that meditates these things diligently yet i will adde this . a drop of ink fallen upon paper , defends it self by its roundnesse ; yet put a moist pen to it , you ●●ll see the drop run up into into it . see , it ●●es not downward , ( as it should by rea●●● of its heavinesse ) but upwards , that it ●●y joyn it self to a greater quantity there●● . xi the motion of sympathie , and antipathy , ●hat , whereby a like body is drawn to its like , 〈◊〉 driven away by its contrary . now this similitude is of the spirit that habits in it . this motion is very evident in ●●ne bodies , ( as in the loadstone , which ●●aws iron to it , or else leaps it self to the 〈◊〉 ) in others weak , and scarce sensible , as 〈◊〉 example in milk , the cream whereof se●rates it self by little and little , from the hevie parts , and gathers it self to the top ) some things , it is as it were bound ; un●●sse it be losed some way or other , that ap●ears in melted brasse : wherein metals are ●●parated one from another , by the force of 〈◊〉 fire , and by the virtue of sympathy eve●● thing gathers it self to its like , ( lead to ●●ad , silver to silver , ) and flows together in 〈◊〉 peculiar place . xii motion of continuity is , that whereby ●atter follows matter , shunning discontinuity . as when you suck up the air with a pipe , ●●tting one end thereof into the water , the water will follow the air , though it be up●ward . for we said before , that the world ▪ a living creature would not be cut , the livin● spirit uniting all things . xiii the motion of impulsion ( or cession● is that whereby matter yeelds to matter , th● presseth upon it . so water yeelds to a stone that com● down into it , that it may sink ; so a ston● to the hand that thrusts it , &c. for a bod● will not endure to be penetrated , it had rather yeeld , if it can . if it cannot all , the pa●● yeeld , as wee may see it happen in eve● breake , bruise , rent , wearing , cutting for the weaker yeelds every where to th● stronger . xiv the motion of libration is , that where in the parts wave themselves too and fro , th●● they may be rightly placed in the whole . as when a ballance moves it self , now this , now that way . xv the motion of liberty is , that whereby a body or a part thereof , being violently move● out of its place , and yet not plucked away , returns thither again . as when a branch of a tree bent forcibly and let go again , betakes it self to its positure . a scheame of motions . motion therefore is of spirit light which is called the motion of agitation . diffusion . matter which is caused by the fire and is called the motion of expansion . contraction . some body drawing by connaturalitie , as of aggregation . a secret virtue , as of sympathie . connexion , as of continuitie . thrusting or inforcing , as of impulsion it self , ( that it may be well with it self ) as the motion of libration . libertie . an example of all these motions in the f●●tion of the macrocosme or great world. first , the spirit moved it self upon the●ters with the motion of agitation . then light being sent into the matter , penetra● it every way with the motion of diffusion and by the matter above , where the li●● passed through , being heated and rarif●● dilated it self with the motion of dispa●● but below , it coagulated it self with the●●tion of contraction . and all the more su●● parts gathered themselves upwards , the 〈◊〉 downwards , with the motions of agregation and sympathy : ( for a more o●● sympathy and antipathy was put in things afterwards . ) and whither soever o● part of the matter went , others followed 〈◊〉 the motion of continuity : or if one rush● against others , they gave way by the motion of impulsion . but the grosser parts did poi●● themselves , ( flying from the heat whic● came upon them from above ) about th● center , to an exact globosity , with th● motion of libration . there was no motion o● liberty , because there was no externall violence , to put any thing out of order . an example of the same motions in the microcosme , or little world. in man , ( and in every living creature ) the food that is put into the belly , grows hot with incalescency ; here you have the motion of expansion , then by the motion of sympathie every member attracts to it self , that which is good for it : but by the motion of antipathy superfluous things are driven forth , as unprofitable and hurtfull to them . then the blood is distributed equally to the whole body upwards and downwards by the motion of libration . and being assimilated to the members , it is condensed , that it may become flesh , a membrane , a bone , &c. by the motion of contraction , lastly , the air in breathing drawn in and let forth , shews the motion of continuity , and contiguity . ( for when the lungs are distended , the air enters in , ( least their should be a vacuum ; ) but when the lungs contract themselves , the air gives way . ) the motion of liberty will appear , if you either presse down , or draw up your skin : for as soon as you take away your hand , it will return to its situation . lastly , if you fall from any place , there will be the motion of aggregation , for you will make toward the earth , as being weight and earth your self . xvi if motions be infolded , they either increase or hinder one anothers force . you have an example of the first , if you cast a stone towards the earth , for here the motion of aggregation and impulsion , are joyned together . of the latter , if you cast a stone towards heaven : for here the motion of impulsion striveth against the motion of aggregation , in which strife , the stronger at length , overcomes the weaker ; the naturall that which is but accessory . xvii compound motion is in living creatures , when they doe of their own accord , move themselves from place to place . namely , birds by flying , fishes by swimming , beasts by running : of which we shall see chap. . how every one is performed . also , naturall philosophers call that a compound motion , when a thing is wholly changed , either to being or not being , or to another kind of being , though it continue in the same place , but we call these mutations , and they are to be handled in a pecuculiar chapter , the third from this . chap. iv. of the qualities of things . the matter is variously mingled with the spirit , & light , by these various motions , and from this various mixture , come various qualities , so that this thing is called , & is such a thing , that such a thing , again , another such , or such a thing : which we must now consider ; & these talities , or qualities , are some of them generall , common to all bodies ; others speciall , proper to some creatures only . the first are to be laid open here together for all once , the other hereafter in their places . i a quality is an accident of a body , in regard of which every thing is said to be such or such . ii there are qualities in every body , as well intangible , spirituall , and volatile , as grosse , tangible , and fixed . for a body is ( as we saw cap. . in the description of matter , aphor. . and of the spirit aphor. . either intangible , or nolatile , which they also call spirituall , as breath , air . tangible namely , water , and all fluid things . earth , and all consistent things . the qualities therefore , which we will treat of , shall be common to all these . for it may be said , both of a stone , and of water , and of air , and of the spirit that is inclosed in a body , that it is fat or raw , hot or cold , moist , or dry , thick or thin , &c. iii the qualities are the grounds of all forms in bodies . for the former causes a living creature to differ from a stone , a stone from wood , wood from ice , and the forme consists of qualities . therefore the doctrine of qualities is exceeding profitable , and as it were the basis of naturall science ; which because it hath been hitherto miserably handled , the light of physicks hath been maimed , and by that means obscure . iv a quality is either intrinsecall , and substantiall , or extrinsecall and accidentall . of the substantiall qualities , sulphur , salt , and mercury . v a substantiall quality arising from the first mixture of the principles is threefold . aquosity which the chymicks call mercury oleosity sulphur consistency salt. n. these flow immediately from the combination of the first principles . fire sulphur salt spirit matter mercury . for as in the beginning the spirit conjoyned with the matter , produced the moving of the waters ; so mercury is nothing but motion , the first fluid thing , which cannot be fixed , nor conteined within alimit ; and salt is dry and hot , and uncorruptible , just as spirit and fire ; it is preserved by fire , it is dissolved with water , or mercury , but turns neither to flame , nor smoak , though it is a most spirituall creature , and every way incorruptible . and sulphur , what is it but matter mixt with fire ? for why doth it delight in flame , but that it is of a like nature ? and in compound things , it is the first thing combustible , or apt to be inflamed . n. . but beware that you understand not our vulgar minerall salt , sulphur , and mercury , ( or quicksilver . ) for these are mixt bodies : salt earth , sulphurie earth , mercurial water : ( that is , matter wherein salt , sulphur , and mercury , are predominant , yet with other things adjoyned ; for salt hath parts apt to be inflamed , and sulphur some salt , and some mercury , but the denomination is from the chiefest . ) those qualities cannot be seen as they are in themselves , but by imagination ; but they are in all things , as chymicks demonstrate to the eye : who extract crude and watery parts out of every wood , stone , &c. and other fat and oily parts ; and that which remains , is salt , that is ashes ; so the thing it selfe speaks , that some liquor is mercurious ; ( as vulgar water and flegme ) other sulphury ; ( as oil and spirit of wine ) other salt and tart ( as aqua fortis ) also we find by experience , in the benummings and aches of the members ; that some vapours are crude , others sharp . vi god produced the qualities intrinsecally , that the substance of every body might be formed . for ☿ sulphur salt giveth unto things fluidity , coition , crudity . 〈◊〉 , cleaving together , fatnesse . consistency , hardness . aptnesse to break . and from thence incōbustibility , inflammability incorruptibility . that mercury giveth fluidity , and easie coition of the matter , appears out of quicksilver , which by reason of the predominancy of mercury , is most fluid : so that it will not endure to be stoped or fixed . it is also most crude , so that it can neither be kindled nor burned : but if you put fire to it , flees away into air . now that the coagulation of bodies is from sulphur , as it were glue , appears from hence that there is more oil , in dry , solid , and close , bodies , then in moist bodies ; also because ashes ( after that the sulphur is cousumed , with five ( if you power water on them clear not together in a lump , but with oil or fat , they cleave together . now chymicks extract oil out of every stone , leaving nothing but ashes , no part cleaving one to another any longer . and that salt gives consistency , appears by the bones of living creatures , out of which chymicks extract meer salt , also all dense things leave behind them much ashes ( that is salt . ) god therefore with great counsel tempered these three qualities together in bodies . for if mercury were away , the matter would not flow together to the generation of things : if salt , nothing would consist together , or be fixed ; if sulphur , the consistency would be forced , and yet apt to be dissipated . lastly , if there were not sulphur in wood , and some other matters , we could have no fire , but solar , on the earth ( for nothing would be kindled ) and then what great defects would the life of man endure ? of the accidentary or extrinsecall qualities of bodies . so much of the substantiall qualities : the accidentary follow . vii an accidentall quality is , either manifest , or occult . viii a manifest quality is , that which may be perceived by sense , and is therefore to be called sensible . as heat , cold , softnesse , roughnesse . ix an occult quality is , that which is known only by experience , that is by its effect , ( as the love of iron in the loadstone , &c. ) therefore it is called insensible . n. the manifest qualities proceed from the diverse temperatures of the elements , & substantificall qualities ; the occult immeditely from the peculiar spirit of every thing . x the sensible quality is five fold , according to the number of the senses , visible , audible , olfactile , gustatile , tangible : that is colour , sound , odour , savour , tangour . let not the unusuall word tangor , offend any ; it is feigned for doctrines sake ; and analogy admits it , for if we say from caleo , calor ; from colo , color ; from sapio , sapor ; from amo , amor ; from fluo , fluor ; from liquo , liquor ; from clango , clangor ; from ango , angor ? why not also from tango , tangor ? of the tangible quality . xi the tangible quality ( or tangor ) is such , or such a positure of the parts of the matter in a body . xii the copulations thereof are twelve ; for every body in respect of touch , is , rare or dense , moist or dry . soft or hard . flexible or stiffe . smooth or rough . light or heavy . hot or cold . of every of which , we are to consider accurately , what and how they are . xiii rarity , is an extension of the attenuated matter through greater spaces : density on the contrary , is a straighter pressing together of the matter into one . for all earth , water , air , and spirit , is sometime more rare , sometime more dense ; and we must note that there is not any body so dense , but that it hath pores neverthelesse , though insensible . that appears in vessels of wood and earth , which let forth liquors in manner of sweat ; also in a bottle of lead filled with water , which if it be crushed together with hammers , or with a presse , sweats forth a water like a most delicate dew . xiv humidity ( or humour ) is the liquidnesse of the parts of the body , and aptnesse to be penetrated by one another ; siccity on the contrary is a consistency , and an impenetrability of the parts of the body . so a clot hardned together either with heat or cold , is dry earth , but mire is moist earth , water is a humid liquour , but ice is dry water , &c. xv softnesse is a constitution of the matter somewhat moist , easily yeilding to the touch : hardnesse is a drynesse of the matter not yeelding to the touch . so a stone is either hard or soft , also water , spirit , air , &c. xvi flexibility , is a compaction of the matter with a moist glue , so that it will suffer it self to be bent : stifnesse is a coagulation of the matter with dry glue , that it will not bend but break . so iron is stiffe , steel flexible . so some wood is flexible , other stiffe , but note that the flexible is also calld tough , the stiffe brittle . xvii smooth is that which with the aequality of its parts doth pleasantly affect the touch : rough is that which with the inequality of its parts doth distract and draw asunder the touch . note , in liquid things , the smooth is called mild , the rough tart ; so marble unpolished is rough ; polished it is smooth . water is rough , oile is mild ; a vehement and cold wind is rough and sharp ; a warm air is mild . so in our body , humours , vapours , spirits , are said to be mild or sharp . xviii lightnesse is the hasting upwards of a body by reason of its rarity and spirituosity : heavinesse is the pronenesse of a dense body downwards : as that appears in flame , and every exhalation , this in water and earth . n. w. i how this motion is made upwards and downwards by a love of fellowship , or of things of the same nature , hath been said cap. . the inaequality of heavinesse or ponderosity , is from the unequall condensation of the matter . for look , how much the more matter there is in a body , so much the more ponderous it is : as a stone more then wood , metals more then stones , and amongst these gold , quicksilver and lead most of al , because they are the most compacted bodies . amongst all heavy things , gold is found to be of greatest weight : spirit of wine , or sublimated wine of least . and the proportion of quantity betwixt these two , is found not to exceed the proportion of parts : so that one drop of gold is not heavier than one and twenty drops of spirit of wine . xix heat is a motion of the most minute parts of the matter reverberated against it self , penetrating and rending the touch like a thousand sharp points : but cold is a motion of the parts contracting themselves . n. w. it appears that heat and cold , are motions and fixed qualities : because there is no body found amongst us perpetually hot or cold , as there is rare and dense , moist and drie , &c. but as a thing heats or cools ; the which is done by motion . because sense it self testifies , that in scorching the skin and members are penetrated and drawn asunder , but in cold they are stopped and bound , therefore it is a motion . because whatsoever is often heated , ( though it be metall ) is diminished both in bignesse and in weight , till it be even consumed , and whēce is that , but that the heat casting forth a thousand atomes doth weare and consume away the matter ? now it is called a motion of parts , and that reverberated against it self : for that which is moved in whole , and directly ( not reflexedly ) doth not heat ; as wind , a bird flying , &c. but that which is moved with reverberation , or a quick alteration , as it is is in the repercussion of light ; in the iterated collision of bodies , in rubbing together friction , &c. but we must distinguish betwixt calidum , calefactivum , and calefactile , calidum or calefactum , is that which is actually hot , and scorcheth the touch , as flame , red hot iron , seething water , or air ( which also receiveth amost violent heat , ) &c. n. w. among all things that are known to us , fire is most hot ; wee have nothing that is most cold but ice ; which notwithstanding is farre off from being opposed in its degree of cold to the degree of heat in fire . calefactivum is that which may stirre up heat ; as motion , and whatsoever may procure motion ; namely fire ; and pepper , and all sharp and bitter things , taken within the body : for motion is from fire , and fire from motion , and heat from them both . for as fire cannot but be moved ( else it presently goes out , ) so motion cannot but take fire ; as it appears by striking a flint , and rubbing wood something long . therefore both are calefactive , but fire is further said to be actually hot , calefactive things are commonly called hot in potentiâ . calefactile is that which may easily be heated as air , and after air fat things ( oile , butter , ) then wood , then water . for in these because the parts are somewhat rare , they are the more easily moved to agitation . stones and metals because they have their matter compacted , do not easily admit of heat ; but retain it the longer after it is admitted , because it cannot easily exhale by reason of the straight pores . and this is the cause , why all things consisting of small particles , as feathers , hairy skins , and all rough things , ( yea , and all sorts of dust ) do either alwayes retein heat , ( by a certain agitation of the aire inclosed ) or at least easily receive it , by some transpiration raised only from a living body . we must also note , that all these tactile qualities , may be said of the same body in a diverse manner ; namely , in respect of another body , as water in respect of air , is a dense and heavy body ; in respect of earth , or a stone , rare and light ; yea and by reason of the touch thus and thus disposed , it seems to be on this , or that manner ; for example , warm water seems cold to a hot hand , hot to a cold hand . the diverse effects of heat , are to be considered also according to the diversity of the object . the perpetuall effect of heat is attenuatiō : but after different manners in a matter that is liquid sulphury , which it kindleth , turnes to flame , and snatcheth upward . mercuriall , which it rarifies , and stretcheth forth , as may be seen in the evaporation of water : also in the desiccation or drying up of earth , wood , &c. in which all the humour & moisture that is , turnes and evaporates into air . consistent which if it have parts that are glutineus or sulphury , it forces them to melt , as may be seen in suet , wax , metals . ashy or salt , it forces them to be condensed , by the drying up of the moisture : and also to break if you force them the more ; as wood , a clot , a tile , &c. ( and so hardning is an effect of heat by accident . ) of tasts . xx the gustatile quality is called savour or taste ; which is a tempering of the first qualities by heat and cold .   temperate sulphur giveth sweetnesse .   adult . bitternesse . for salt of its own nature . giveth softnesse . for the mordaity of all these , argues salt. combust . sharpnesse . indifferently sowernesse . cooled . bitternesse . extreamly cooled . & austerity . it appears therefore , whence herbs , fruits , parts of living creatures , and minerals have their savours ; namely , from salt and sulphur , diffused every where , whereof every creature sucketh in more or lesse according to its nature . mercury is of it selfe without taste ; ( as we note in flegme ) but the others are soaked thereby , as ▪ also by the severall degrees of cold or heat , so that they are more or lesse sweet , bitter , salt , &c. of smels . xxi the olfactile quality is called odour ; which is a most thin exhalation of the taste . yet sulphury things yield more smell then salt things and hot things more then others ; because heat attenuates , and spreads into the air . hence gardens and ointment boxes , are so much the sweeter , by how much the hotter the air is ; yet by how much the sweeter they are , so much the sooner they lose their smell , that odiferous sulphureous quality being exhaled by little and little . of sounds . xxii the audible quality is called sound ; which is a cleaving of the air sharply stricken , flowing every way . every motion of the air doth not give a sound , but that motion whereby the air is suddenly divided and parted . now a sound is either acute or obtuse ; pleasing or displeasing ; according as the body , that smiteth the air , is acute or obtuse , smooth or rough . the naturall kinds of sound are : tinkling , when the air blows through some sharp thing . murmur of running water : ratling of thunder : rustling of leaves : bellowing or lowing of oxen : roaring of lions ; hissing of serpents : and the voices of other living creatures . of colours . xxiii the visible qualitie is called colour ; which is light diversly received in the superficies of bodies , and tempered with the opposite darknesse , as whitenesse , blacknesse , greennesse , &c. obser. . that colour is nothing in it self , but light diversly reflected from things , appears ; because as it is not seen without light , so it is not found to be any thing by any other sense , or by reason : neither is it therefore . because colours as well as light diffuse themselves through the aire , and are in the eyes of all beholders . now we saw before , that the diffusive motion was proper to the light , therefore colour is indeed nothing , but light diversly tinct with the diverse superficies of things . because light being reflected after severall manners in the same matter , produceth severall colours . we see that , for example sake , in a cloud , which is in it self like it self , yet it appears to us sometimes whitish , sometimes blackish , sometimes ruddy , according as it is opposed to the light . in like manner we see in the rainbow ( which is nothing else but the resolution of a cloud into most small drops of water ) yellow , green , flame and sky-colour , as it appears also in chrystall dust turned towards the light ; which shew plainly , that colour is nothing else but a different tincture of light from the different incidencie thereof . but there ( in the rainbow and glasse ) the colours passe through ; because the matter it selfe is fluid and transparent : in fixed bodies , colours are also fixed ; but after a way known to god , rather then to us . obser , . that from the receptibility of colours , a body is called pellucid , or opacous . pellucid ( transparent and diaphanous ) is that which gives the light a passage through it , and is therefore neither coloured nor seen , as air : and in part water , glasse , chrystall , a diamond , &c. ( that air is not coloured , that is tinct with light , appears in a room close shut up on every side , if you let in a beam of the sun at a hole , for that will passe through the whole room , and yet will appear no where , but on the opposite wall or pavement : or unlesse you interpose your hand or some other dense thing : or the dust be raised , and the atomes of it flie in that quantity as to reflect the light . ) opacous is that which doth not give the light a passage , but reflects it , and therefore it is coloured and seen : as earth , wood , a stone , gemme , and waters coloured : and this light reflected from an opacous body , is properly called colour : of which there are six kinds , white , yellow , green , red , skie-colour , black . white , is light reflected with its own proper face . yellow is light tinct with a little darknesse . green , is light in a middle , and most pleasing temperature of light and darknesse . red , is light more inclining to darknesse . skie-colour , is light more then halfe dark . black , last of all , is the non-repercussion of the light , by reason of a dark superficies . every of these colours hath under it diverse degrees and species , according to the various temperature thereof with the others ; which we leave to the speculation of opticks and painters . xxiv there remains a quality which is perceived by two senses , touch and sight , namely figure ; whereby one body is round , another long , another square , &c. but the consideration of this is resigned to the mathematicks . of an occult quality . xxv an occult quality is a force of operating upon any otber body , which notwithstanding is not ●iscovered , but by its eff●ct . for examp . that the loadstone draws iron : that poisons assaile , and go about to extinguish nothing but the spirit in bodies : that antidotes again resist poison , and fortifie the spirit against them ; that some herbs are peculiarly good for the brain , others for the heart , others for the liver , and such like . such kind of occult qualities as these god hath dispersed throughout all nature , and they yet lie hid for the better part of them , but they come immediately from the peculiar spirit infused into every creature . for even as one and the same matter of the world , by reason of its diverse texture , hath gotten as it were infinite figures in stones , metals , plants , and living creatures ; so one and the same spirit of the world , is drawn out as it were into infinite formes , by various and speciall virtues , known to god , and from these occult qualities sympathies and antipathies of things do properly arise . chap. v. of the mutations of things , generation , corruption , &c. from the contrarieties of the qualities , especially of cold and heat , ( for these two qualities are most active ) those mutations have their rise , to which all things in the world are subject : which we shall now see . i mutation is an accident of a body , whereby its essence is changed . namely , whither a thing passe from not being to being ; or from being to not being ; or from being thus to being otherwise . ii all bodies are liable to mutations . the reason , because they are all compounded of matter , spirit and fire : which three are variously mixed among themselves perpetually . for both the matter is a fluid and a slipperie thing , and the spirit restlesse , always agitating it self ; and ( heat raised every where by light and motion ) doth eat into , rent , and pluck asunder the matter of things . from thence it is , i say , that nothing can long be permanent in the same state . all things grow up , increase , decrease , and perish again . hence also the scriptures affirm , that the heavens wax old , as doth a garment , psal. ● . v. . iii the mutation of a thing , is either essentiall or accident all . iv essentiall mutation , is when a thing begins to be or ceases to be : the first is called generation , the other corruption . for example ; snow , when it is formed of water , is said to be generated , when it is resolved again into water , to be corrupted . v an accident all mutation of a thing is , when it increases or decreases , or is changed in its qualities : the first is called augmentation , the next diminution , the last alteration ( which we are now to view severally how they are done . ) of the generation of things . vi generation is the production of a thing , so that what was not , begins to be . thus every year , yea every day infinite things are generated through all nature . vii to generation , three things are required , seed , a matrix , and moderate heat . these three things are necessary in the generation of living creatures , plants , metals , stones , and lastly of meteors , as shall be seen in their place . viii seed is a small portion of the matter , having the spirit of life included in it . for seed is corporall and visible ; therefore materiate , and it is no seed , except it contein in it the spirit of the species , whose seed it should be : for what should it be formed by ? therefore seeds out of which the spirit is exhaled , are unprofitable to generation . ix the matrix is a convenient place to lay the seed , that it may put forth its vertue . nothing is without a place , neither is any thing generated without a convenient place ▪ because the actions of nature are hindred . now that place is convenient for generation , which affordeth the seed . a soft site . circumclusion , least the spirit should evaporate out of the seed being attenuated . veins of matter to flow from elsewhere . n. w. and there are as many matrixes or laps , as there are generations , the aire is the matrix of meteors ; the earth of stones , metals , and plants ; the womb of living creatures . x heat is a motion raised in the seed , which attenuating its matter , makes it able to spread it self by swelling . for the spirit beng stirred up by that occasion agitateth it self , and as it were blowing asunder the attenuated parts of the matter , disposeth them to the forme of its nature . this is the perpetual processe of all generation , and none other . from whence hereafter ( under the doctrine of minerals , living creatures , plants ) many things will appear plainly of their own accord . yet we must observe that some things grow without seed , as grasse out of the earth , and worms out of slime , wood , and flesh putrified : yet that is done by the vertue of the spirit diffused through things ; which wheresoever it findeth fit matter , as a matrix , and is assisted by heat , presently it attempts some new generation , ( as it were the constitution of a new kingdom ) . but without heat ( whither it be of the sunne , or of fire , or the inward heatof a living creature it matters not , so it be temperate ) there can be no generation , because the matter cannot be prepared , softned , or dilated , without heat . of the augmentation of things . xi everything that is generated , increaseth and augmenteth it self , as much as may be : and that by attraction of matter , and ●ssimilation of it to it self . for wheresoever there is generation , there is heat : and where there is heat , there is fire ; and where there is fire , there is need and attraction of fewell . for heat , because it always attenuateth the parts of the matter which exhale , seeks and attracts others wherewith it may sustein it self : ( as we see it in a burning candle ) and a portion of matter being attracted and applyed to a body , taketh its form by little and little , and becomes like unto it , and is made the same . for by the force of heat , of heterogeneous , things become homogeneous : the spirit of that body , in the mean time , attracting also to it self somewhat of the spirit of the universe , and so multiplying it self also . so stones minerals , plants , living creatures , &c. grow . of diminution xii whatsoever hath increased , doth at some time or other cease to increase , and begin to decrease and that for and through the arefaction of the matter . namely , for because the heat increased with the body , increasing , doth by little and little and little consume the thin and fat parts thereof , and dry up the solid parts , so that at last , they are not able to give assimulation to the matter flowing in , and that for want of gluten , and therefore the body fadeth , and withereth and at length perisheth . of the alteration of things . xiii no body doth always retein the same qualities , but changeth them variously . for example , wood when it grows , is thin and soft , afterward it is condensed & hardned , especially being dried : fruit on the contrary , as it ripens grows rare and soft , changing its colour , savour and smell for it is the law of the universe to be subject to vicissitudes : as also to corruption , of which it here follows . of the corruption of things . xiv every body is liable to corruption . because compounded of a decaying matter , and an agitable spirit ; which may be disposed according to the mutation of the heat . therefore seing that alterations cannot be hindred , neither can perishing . and hence perhaps every materiall thing is called corpvs , as it were corrupus , because it is subject to corruption . xv all corruption is done , either by arefaction or putrefaction . for we speak not here of violent corruption , which is done by the solution of some continued thing , ( as when any thing is broken , rent , bruised , burnt , &c. ) but of naturall corruption , which brings destruction to things from within , i● it is manifest that this can be done no way , but by arefaction or putrefaction . xvi arefaction is when afflux of matter is denied to a body , and the heat included , having consumed its proper humour , dries and hardens the rest of the parts , and at length forsakes them . so hearbs , trees and living creatures , &c. wither . xvii putrefaction is when the spirit is exhaled from a body , and the parts of the matter are dissolved , and return into their het●rog●neous parts . for then the watery parts are gathered to themselves ( therefore putrefied things give an evill sent ) the oily parts to themselves , whence putrefied things have always some unctuosity ) the dregs to themselves ( whence that confusion in putrified things and unpleasant tast , &c. ) and hence it is easie to finde the reason , why cold , salt and drying hinder putrefaction ? namely , because cold stops the pores of a body , that the spirituall parts cannot go out and exhale : but dryed things are exhausted of th●se thin parts , which might be putrefied : salt last of all bindeth the parts of the matter within , and as it were holds them with bands , that they cannot gape , & let forth the spirit . again , it may easily be gathered from hence , why hard and oily things are durable ? namely , because hard things have much salt , which hindereth putrefaction ; but they are destitute of humidity ( the provocation of putrefaction . ) and oily things , because they do not easily let go their spirit , by reason of their well nourishing and gentle usage of it : ( suet and fat putrifie , because they have loose pores , and some aquosity . ) n. w. we must neverthelesse observe , that not onely soft things ( herbs , fruits , flesh ) putrifie , but also the hardest bodies , namely , stones and metals . for the rust of these is nothing else but the rottennesse of the inward parts , spreading it self abroad through the pores , xviii out of that which hath been said , it may be gathered , that the world is eternall potentially . for seing that not any one crum of matter can perish , nor the spirit be suffocated , nor the light be extinguished , nor any of them fly forth out of the world , and must of necessity be together , and passe through one another mutually , and act upon one another , it is impossible but that one thing should be born of another , even without end . for that old axiome of philosophers is most true ; the corruption of one is the generation of another . the architect of the world in that manner expressing his aeternity . chap. vi. of the elements ; skie , air , water , earth . we have hitherto contemplated the generall parts of the world , namely , the principles with the common accidents thereof : now follow the species of things , which are derived from the said principles by divers degrees . where first elements come to be considered , as which being framed of the first congresse of the principles , are as it were the bases and hinges , of the whole order of the world . i an element is the first and greatest body in the world of a simple nature . a body , or a substance , for though we called matter , spirit , and light substances also , ( cap. . ) because they are not accidents ; yet because none of them existeth of it self , and apart , but do joyntly make up other substances , the elements and the creatures that follow may with better right be so called . now an element is said to be of a simple nature , in respect of the substances following , which have compound natures , as it shall appear . ii the constitution of the elements is made by light . for light being sent into the world , by its motion and heat began to rouse up the chaos of the matter of the world ; and when it turned it selfe round , ( as yet it turnes ) it purified part of the matter , and made it more subtile , the rest of the matter of necessity setling and gathering it selfe into density elsewhere . iii there are foure elements , skie , air , water , earth . that is , there are four faces of the matter of the world reduced into formes , ( for at the first it was without form ) differing especially in the degree of rarity and density . note . the peripateticks put the sublunary fire , for skie , and call the skie a quintessence . but that same sublunary fire is a meer figment ; the heaven it selfe , furnished with fiery light , is the highest element of the world ; as after the scripture the senses themselves demonstrate . he that is not satisfied with these of ours , but seeks more subtile demonstrations , let him see campanella , verulamius , and thomas lydiat of the nature of heaven , &c. and he will acknowledge the vanity of this aristotelicall figment . iv the skie is the most pure part of the matter of the world , spread over the highest spaces of the world . it is vulgarly called the visible and starry heaven , and by an errour of the greeks ( who , thinking that it was of a solid substance , like chrystal , called it 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 the firmament : but little agreeably to the truth . more conveniently 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 from the hebrew 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 & 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 that is , light and fire , quasi 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ( that is fire above ) and so from burning : as 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 is derived of 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 to burn . for it burneth with an inextinguable light of the stars , whereby it is also purified . the notation of the hebrew word favours this , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 of 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 fire and water . the nature of the heaven is to be liquid in the highest degree volatile and hot . v air is a part of the matter indifferently pure , spread over the lower spaces of the world . the nature of it is to be breathable and passable every way . vi water is a grosser part of the matter of the world reduced into fluidity . the nature of it is to be fluid and moistning . vii the earth is the most grosse part of the matter , as it were the dregs and setling gathered together at the bottom . the nature of it is to be dry and immoveable . viii the elements therefore are all one matter of the world , distinguished by degrees of density and rarity . for where the light is wheeled about , there the matter is most rarefied and pure : below that more grosse , then grosse and fluid , at length in the bottome dregs and a thick setling . therefore this is a meer gradation . for earth is nothing else but thickned and hardned water : water , nothing but thickned air : air , subtilized water : water , liquified earth . but from this difference of density & rarity there ariseth another difference of the same elements , namely , in regard of motion and rest , heat and cold . the water is moveable . ( for it flows ) the air more yet ( for it transfuseth it self here and there ; ) the skie doth nothing but whirle about most swiftly , & that perpetually . also the heaven by reason of its perpetuall motion is hot , ( yea burneth ) perpetually ; the earth by reason of its perpetual rest is cold perpetually : except where it is warmed by the fire of heaven coming upon it , or inclosed in it . ix the elements are transmutable into one another . that is , because the heat raised in the matter may extend and condense it . in the water and air we see that come daily to passe . for who knoweth not , that water doth evaporate , and is turned into air ? that water is made again of vapour , the rain teacheth us . but we may also procure the same mutation in our hand : or in vulgar alembicks in which waters or wines are distilled . let theie be an alembicks void of all matter , filled onely with air . to the long pipe of this that hangeth out apply some narrow mouthed glasse , and stop the pipes mouth carefully , that no air may any way get forth : you shall see that when it cannot dilate it selse locally , it will be coagulated into water in the utmost and coldest corner of it ; ( that is in the glasse . ) you shall see ( i say ) that glasse sweat and distill drops , into which the air heated and rarified in the alembick contracted it selfe . but remove away the fire , you shall see those drops vanish by little and little , and return into air . x aristotle thought that the elements were in a tenfold proportion to one another ; but later men have found them near an hundred-fold that is , that of one drop of earth is made by rarifaction ten drops of water ; and of one of water ten of air . the truth of the latter assertion is easie to be demonstrated , thus . let one take a bladder ( of an oxe or an hog ) and having cleansed it , anoint it with oile to stop the pores , that the air may not get out . to the neck of this ( but having first crushed out all the air ) let him tie the neck of some little glasse , with about an hundreth part of the water which the bladder might contein . let this instrument be set in the hot sun , or in a very hot stove , where the water is by the heat turned into air , it will appear that the bladder will be full . but bring the same bladder swelled with air into the cold , you shall see it ( the vapour turning again into water ) fall again . note . the same hundreth proportion , or near upon , is also observed among colours , for one drop of ink or red will colour an hundred drops of water , not on the contrary ; and that because blacknesse represents the earth in density ; whitenesse the heaven in rarity . but this very proportion varies , because the air is in it selfe somtimes thicker and grosser , somtimes more rare and thin . xi the matter of all the elements , as it is made up of atomes , so it is turned again into atomes : by so much the more subtlely as it is the more subtle in its masse . for example , the earth and every dry and hard thing , is brought into a dust almost indivisible , which may be sifted through a sieve , but cannot penetrate . the water may both be strained and penetrate . for example , through vessels of earth and wood , yea , and of lead as chap. . aphorisme . we have set down an example . air and fire penetrate also through thicker bodies : as heat through furnaces . xii the elements are the four greatest bodies of the world , of which others are generated . that the lesser bodies of the world , which are infinite in number , and in forms , are really compounded of the elements , resolution shewes . for when they are corrupted , they return into the elements . and sense teacheth . for all things have some grossenesse , from the earth ; some liquour from the water ; some spirituosity from the air : some heat from heaven ; and because all things that live , are nourished by these , they are thence called elementa quasi alimenta , as if you should say nourishment , as in bohemian ziwel or ziwent . xiii the elementary matter occupies a place in the world according to its degree of density and rarity . for the earth resteth at the bottome : the water swims upon that : the air fleets above the water : and lastly the skie is in the highest place : you shall see the like spectacle if you pour clay , water , wine , ( especially sublimated ) and oile into a glasse : for every one of these , will occupie a place accotding to its nature . xiv therefore the elements make the four visible regions or sphears of the world . for the earth is a globe ; which the water naturally encompasseth round ; the air it : the skie the air : after the same manner as in an egge the yelk is encompassed with the white ; and that with the skin and shell . xv of the elements there are two extreams , the skie and earth ; as many 〈◊〉 air and water . they are called extream aad mean both in regard of their sites , and of their accidents . for the skie is in the highest place , most thin and hot : the earth in the lowest , most thick and cold : skie the first moveable ; earth the first resting . the air and water as they partake of the extreams , so of their accidents : being somtimes either lesse thick or thin , moving or still , hot or cold . xvi but because the elements were prepared not for an idle spectacle , but for strong operation upon one another ; the creatour did somewhat change that order , and commanded two sorts of water to be made , and two sorts of fire . xvii for part of the water is placed above the highest part of the skie : and on the contrary , part of the fire is taken from the skie , and shut up into the bowels of the earth . both these may seem paradoxes : and therefore need demonstration . and as touching the waters it is manifest by the testimony of moses , that god made ( the second day ) the expansum of the heaven , which might divide betwixt the waters which are under the expansum , & the waters above the expansum , gen. . , , . what can be more clear ? now whereas some modern divines interpret it of the waters of the clouds , that is too cold . they say that jer. . . the rain waters are signified by the name of the water in heaven ; and therefore here also . but i answer . that the waters in heaven are one thing , and the waters above heaven another : rain might be called water in heaven : because the air was by the hebrews called the first heaven : but it cannot be called the waters above heaven , as these of which moses speaks . that the waters of the clouds are not waters in act , but vapours : but moses speaks of waters . for he sayes expresly , that in the first seven dayes there was no rain . ( cap. . ver . . ) but he sayes that those waters above the expansum were presently made the second day ; therefore they are some thing else then rain water . he sayes , that the waters were seperated from the waters , but the waters of the clouds are not separated from the waters of the sea , and of rivers . for they are perpetually mingled : vapours ascending , rain descending . he sayes , that the expansum was in the middest betwixt the waters and the waters : but how can that be said of the clouds , which are below the expansum , and reach not to the thousandth part of its altitude ? lastly , psalm . placeth the waters above the heaven , next of all to the heaven of heavens , v. . but reckons up clouds and rain afterwards , among the creatures of the earth , ver . . what need we any other interpretation ? reason perswades the same thing most strongly . for setting down the principles of the world in that order , wherein we see them set down by moses ; it was necessary , that the matter being scattered by the light rolling about ; should flie hither and thither , and coagulate it selfe at the terms of the world on both fides , that in the middle where the light went , ( and goes yet ) there should be pure skie ; but that on both sides above and below , the mathardning it self , should grow thick . we see it done here below : why not above also ? especially god himself intimating it . let it be so , because naturally it cannot be otherwise . but that there is fire included in the earth the eructations of fire in aetra , vesuvius , hecla , &c. do shew . the springs of hot waters every where , the progeneration of metals , even in cold countreys : and other things which can come from nothing else but from fire , which shall be looked into in that which follows . lastly there is a testimony extant in the book of job chap. . v. . bread commeth out of the earth , and under it is turned up as it were fire . let the reader see thomas lydiats disquisition concerning the originall of fountains , and there he shall see it disputed at large , and very soundly . xviii the waters above the heaven are there placed for ends known to god , but the use of fire under ground , is well enough known to us also . yet we may say something of these waters by conjecture . as namely , that it was meet , that there should be visible termes of the visible world : and that the heat of the frame ever rolling , had need of cooling on the other side also : and the like . but that of the fire under ground , mountains and valleys , and caves of the earth are produced , and also stones , metals , and juyces generated , and many other things we shall see in that which follows : for without heat , there is no generation , because there is no motion . of the skie in specie . xix the skie is the highest region of the most vast world , the dwelling place of the stars . xx the skie is the most liquid part of the whole world , and therefore transparent , and most moveable . for by the motion and heat of the sun always present , it is perpetually attenuated to an exceeding subtlety . xxi the whole skie is moved about , because that burning and ever flying light of the stars , hurries it about with it . that appears , by reason : for if the starres were moved in the heaven immoveable ( after that manner that birds are carried in the air , and fishes in the water ) that penetration of the heaven would not be without violence ; neither could it be performed with so great celerity , nor with so aequable a course , by reason of the resistance . therefore the starres are carried in heaven in all respects , as clouds in the air , that is , with their charriot . by sense , for we see that our fire carries away with it the matter which it hath caught and attenuated , namely , vapours , smoaks , flames : why not the heavenly fire also ? which comets also shew to the eye , of which we shall see more : chap. . . the same is to be gathered out of moses words accurately considered . ( gen. . v. . & . of the air . xxii the air is the lowest region of the expansum , the abode of the clouds and birds . in scripture , it is signified by the name of the first heaven . yet it penetrates water and earth , to fill up their cavities because there is no vacuum . xxiii the air is of a middle nature betwixt the heaven and the water , in respect of site and qualities . yet it is thicker where it joyns to the earth and water ; and thinner towards heaven . therefore in the highest tops of some mountains , neither men can live , nor trees grow , because of the thinnesse of the air , by reason of which it is neither sufficient for the breathing of living creatures , nor for the growth of plants . xxiv the air neer the earth in summer is hot , ( by the vehement repercussion of the suns verticall beams : ) in winter , ( by reason of the obliquity and obtuse reflexion of the beams ) it cannot be heated : above it is always cold , yet most in summer , when it is pend in on both sides with the heat of the heaven , and of the earth . of the water . xxv water is thickned air . washing and and moistning the earth ; the abode of fishes . xxvi water of its own nature is onely moist and fluid : to the rest of the qualities indifferent . obs. . the fluidity of the water is such , that if you give it never so little declivity , it runs . but the humidity is unequall according to the degree of rarity and density . for a ship sinks not so deep in the sea , as in a river : because the sea water is thicker and drier . obs. they adde commonly , that water is naturally cold , by a twofold argument because it cooleth . because it extinguisheth fire , but i answer it cools not by its coolnesse , but by its crudity . but it quencheth fire after the same manner , as hot water and wine , do , though they be hot , not because they are contrary to fire , but because fire is nourished with the thinner parts of the wood , but if abundance of water be cast on ( or any fluid thing , even oyl ) the pores are stopped , and the fire is quenched . otherwise fires are made of bitumen , ( which is not a porous matter ) that burn in the very water , which we see done also in lime . lastly , great fires are nourished with water . we see also that there is sometime hot , sometime cold water , not onely in rivers , but also breaking out of fountains , according as it is affected ; yet it may not be dissembled in the mean time , that air is more prone to heat , by reason of its rarity ; water to coldnesse by reason of its thicknesse . xxvii the water at first covered the earth round about ; but ( on the third day of the creation , it was gathered into certain channels , ( which are called seas , lakes , pooles , rivers , &c. ) that this was done at the command of of god. moses testifies in these words . let the waters be gathered together into one place , that the dry land may appear gen. . v. . but david ( relating the processe of the creation ) describes the manner also . ps. ● v , , , . that thunders were raised , by which the mountains ascended , the valleys descended , but the waters were carried steep down into their channels : and that in this sort , a bound was set them , that they might not return to cover the earth . whence it is very likely , that that discovery of the surface of the earth , was made by an earthquake : but that the earthquake was produced by the fire sunk into the earth ; which giving battle to the cold there conglobated , shook the earth , and either caused it to swell variously , or rent it asunder . whence those risings a●● fallings in the surface of the earth ( that is mountains and valleys ) were made : but within caves and many hollow places . this done , the waters of their own accord betook themselves , from those swelling eminencies to thc low and hollow places . this pious conjecture will stand so long , as no more probable sense can be given of this scripture . and what need many words ? common sense testifies , that mountains are certainly elevated , valleys and plains depressed . therefore of necessity that was sometime so ordered ; but not in the first foundation of the earth the second day ; for then the grosser parts of the matter flowing about poised themselves equally about the center , therefore it was about the third day , when the face of the earth appeared , and the waters flowed into their channels . but besides perhaps god doth therefore permit earthquakes yet to be sometimes , and by them mountatains and valleys and rivers to be changed , that we may not be without a pattern , how it was done at the first . xxviii the water then is divided into seas , lakes , rivers and fountains . xxix the sea is an universall receptacle o●●●aters , into which all the rivers of the earth unburthen themselves . which uery thing is an argument that the sea is lower then the earth : for rivers run down , not up again . xxx the sea is one in it self ; because it insinuates it self into the continent here and there , as it were with strong arms , it hath gotten severall names in severall places . that great sea encompassing the earth is called the ocean , those armes dividing the continent , bayes , or gulfs . for all those gulfes are joyned to the ocean , except the caspian or hyrcanian sea in asia : yet that is thought to have channells within the earth , whereby it joyned to the ocean . xxxi the sea is cf unequall depth commonly srom an hundred , to a thousand paces : yet in some places they say , that the bottome cannot be found . hence the sea is called an abysse . it is probable that the superficies of the earth covered with the water , is as unequal as this of ours standing out of the water , namely , that in some places are most spacious plaines , in other places valleys and depths , and in other places mountains and hils , which if they stand above the water are called islands , but if they be hidden under the water shelves . xxxii the water of the ocean faileth not , because huge rivers and showres continually flow into it ; neither doth it , cverflow becruse it doth always evaporrte upwards in so many parts of it . of the earth . xxxiii the earth is the most dense bedy of the world , as it were the dregs and setling of the whole matter . and therefore gross , opacous , cold , heavy . xxxiv it hangeth in the middle of the universe , encompassed with air on every-side . for being that it is on every side encompassed with the heaven , and is forced by the heat thereof on every side , it hath not whither to go , or where to rest , but in the aequilibrium of the universe . xxxv the earth is every way round . for the forme which at the first it received from the light of heaven wheeling about it , it yet retaineth : except that in some places it is elevated into mountains and hils , by the thunder which was sent into its bowels the third day , in other places again it is pressed down into valleys and plains , for the running down of the rivers : but that doth not notably hinder the globosity thereof . xxxvi the better part of the superficies of the earth is yet covered with water : the lesser part stands out of the water , where it is called dry land , or continent : or if it be a small portion , an island . there are seven continents of the earth ; europe , asia , africa , america peruviana , america mexicana , magellanica , ( or terra australis ) and terra borealis : but there are islands innumerable . xxxvii the earth is in its outward face in some places plain , in others mountainous : but within in some places solid ; in others hollow . that appears in mountains and mines of metal , where is to be seen here stones or clay very close compact , there dens and most deep caves , and endlesse passages , which must needs be thought to have been the work of the thunder , sent into the earth the third day of the creation , ( which penetrating and piercing its bowels so tore them . ) now there are in the earth not only spacious caves and holes , but an infinite number of straighter veins , and as it were pores , which is plain enough by experience . xxxviii the cavities of the earth are full of water , air , fire . for being that there are cavernes , passages and pores , they must needs be filled ; and that with a thin matter . of air no man will doubt . but that there are waters in the cavernes under ground , appeares in the mines of mettall ; and is proved by the testimony of the scripture , which in the history of the deluge , saith that all the fountains of the great deep were broken up ; ( gen. . v. . ) lastly , that there is fire under the earth , we have already seen aphorism . which it is credible , is the relicks of the lightning raised within the bowels of the earth the third day of the creation , ( psalm . ● . v. . ) left there for the working of minerals ; but nourished with sulphureous and bituminous matter , spread through the bowels of the earth . chap. vii . of vapours . if the light of heaven had wrought nothing else upon the matter , but melt it together into the formes of the elements , as it was variously rarified or densified , the world had remained void of other living creatures . but it ceaseth not passing through the elements themselves to scorch them , and scorching them to attenuate them , and attenuating them , to resolve them into vapours : of which condensed again , many severall species of things are progenerated . now then the nature of vapours shall be laid open in the following aphorismes . i vapour is an element rarified , mixed with another element . for example ; the vapour of water , what is it but water rarified and scattered in the air ? smoak , what is it , but an exhalation of wood or other matter resolved ? ii vapour is generated of the grosser elements , earth , water , air ; as of all mixt bodies . of water the matter is evident . for being set to the fire it evaporates visibly ; set in the sun it evaporates sensibly , because even whole pools , rivers , lakes are dried up by little and little , by the heat of the sun . that the earth exhales , you may know by sense , if you put a clot into a dish , ( of earth or pewter ) and pour in water so oft upon it , and let it evapourate with the heat , till there is nothing left , neither of the water , nor of the clay . for what is become of the clot ? it is sure enough turned into aire , with the parts of the water . the vapour of air is invisible ; yet it appears , that there is some . in a living body , where all acknowledge that there are evaporations through the skin and the hair . for then the vapours that go out , what are they but the vapours of the inward vapours , far more subtle then the vapours of water ? fruits , herbs , spices , &c. dried , yea very dry , spread from them an odour , now an odour what is it but an exhalation ! but not ( in this place ) a watery exhalation ( being that there is not any thing watery left in them : ) therefore airy . that mixt bodies do vapour is without doubt : forasmuch as the elements of which they do consist do vapour . understand not only soft bodies ( sulphur , salt , herbs , flesh , &c. ) but the very hardest . for how could a thunder-bolt be generated in the clouds , if stony vapours did not ascend into the cloud ? and it is certain that stones exposed to the air for some ages , ( as in high towers ) grow porous : how , but by evaporation ? and what is the melting of metals , but a kind of vaporation ? for though the metall return to its consistency , yet not in the same quantity , because something is evaporated by putting to the heat . iii heat is the efficient cause of vapour ; which withersoever it diffuseth it selfe , attenuating the matter of bodies , turns it into vapour . for this is the perpetuall virtue of heat , to rarifie , attenuate , and diffuse . iv all is full of vapour throughout the world . for heat , the begetter of vapours , is no where wanting : so that the world is nothing else but a great vaporarie , or stove . for the earth doth alwayes nourish infinite store of vapours in its bowels : and the sea boiles daily vvith inward vapours , and the air is stuft full of them every vvhere . and vve shall see hereafter , that the skie is not altogether free from them . but living bodies of animals and plants , are no●hing but shops of vapours , and as it vvere a kind of alembecks perpetually vaporing , as long as they have life or heat . v vapours are generated for the progenerating of other things . for all things are made of the elements , as it is vvell known , stones , herbs , animals , &c. but because they cannot be made unlesse the elements themselves be first founded , they must of necessity be melted ; vvhich is done vvhen they are resolved into vapours , and variously instilled into things , to put on severall formes . and hence it is that moses testifies , that the first seven days of the world , when there was yet no rain , a vapour went up from the earth , to water the whole earth : that is all things growing out of the earth . read with attention , gen. . ver . , , . vi vapours are the matter of all bodies . for vvho knoweth not , that vvaters and oiles are gathered out of the vapours of alembicks ? vvho seeth not also , that smoak in a chimney turns into soot , that is black dust ? yea that soot gets into the wals of chimneys , and turnes into a stony hardnesse ? after the same manner therefore that clouds , rain , hail , stones , herbs , are made of the condensed vapours of the elements , and living creatures themselves , ( and in them bloud , flesh , bones , hairs ) are nothing but vapours concrete , vvill appear more clear then the light at noon day . vii vapours then are coagulated , some into liquid matter , ( as water , spittle , flesh or pulp ) some into consistent matter , ( as stones , bones , wood , &c. ) that appears , because those liquid things may be turned into vapours , and consistent things into smoke ▪ which they could not , if they were not made of them , for every thing may be resolved into that onely , of which it is made . viii the motion of vapours with us is upwards , because among the thicker elements , they obtein the nature of thinner . for certainly the vapour of water is thinner then water , it self , yea , thinner then the very air : which though it consist of smaller parts , yet they are compacted . and therefore vapor suffers it self to be prest neither by water nor air , but frees it self , still getting upwards , & hence it is , that plants grow upwards , because the vapour included spreading it self , tends upwards . ix one vapour is moist , another dry ; one thin , another thick ; one mild , another sharp , &c. for those qualities which are afterwards in bodies , are initially in their rudiments , that is vapours ; which we may know by experience . for dry smoak pains the eyes : which a humid vapour doth not : there you have sharpnesse : smels also , ( which are nothing but exhalations of things ) do not they sufficiently manifest sharpnesse , sweetnesse , & c ? and chymicks gather sulphur , salt , and mercury out of smoak . therefore all qualities are in vapours more or lesse : whence the bodies afterwards made of them , get such or such an habit or figure . x vapours gathered together , and not coagulated , cause wind in the air , trouble in the sea , earthquake in the earth . of winds . xi wind is a fluxe of the air , ordained in nature for most profitable ends for winds are the besomes of the world ; cleansing the elements , and keeping them from putrefying . the fan of the spirit of life , causing it to vegetate in plants and all growing things . the charriots of clouds rains , smels , yea , & of heat & cold , whether soever there is need that they should be conveyed . lastly , they bestow strong motions for the uses of men ( as grinding , sailing ) xii the ordinary cause of wind is store of exhalations one where , enforcing the air to flow elsewhere . we may in our hand raise a kind of wind four manner of ways ; namely by forcing or compressing , rarifying and densifying air , ( which shall be shewed by examples by and by ) and so many wayes are winds raised in the world , yet they are all referred to that first cause , vapours , as shall be seen by and by . i said that wind may be raised by us by forcing , compressing , rarifying , or densifying ; that may be shewn to children by ocular experiments , for if you drive the air with a fan , doth it not give a blast ? if you presse it when it is drawn into the bellows , doth it not breath through the pipe ? if you lay an apple or an egge into the fire , doth not the rarified humour break forth with a blast ? but this last will be better seen in a bowle of brasse ( which hath but one hole ) put to the fire : especially if you drop in some drops of water . for the air shut in with the water , when they feel the heat , will presently evaporate , and thrust themselves out with a violent blast . which may be also seen , if you put a burning wax candle into a pot well stopped ( having a small hole left at the side ) &c. the fourth way is by condensation of air : if for example , you lay the foresaid bowle of brasse very hot upon ice , and force the thin air included to be condensed again with cold , you shall perceive it to draw it again from without , to fill up the hollownesse of the bowle . therefore so many ways winds are made under heaven ; either because the air is rarified with the heat of the sun , and spreads it self ; or because it contracts it self with being cold , and attracts from elsewhere to fill up the spaces ; or because a cloud scattered , or falling downward ; or else blasts somewhere breaking out of the earth compresse the air , and make it diffuse : or lastly , because one part of the air being moved , drives others before it , ( for here you must remember what was said before . that a drop of water turned into air , requires an hundred times more space . that the air is a very liquid and moveable element : and therefore being but lightly pushed , gives back a long way ▪ ) but yet it is plain that all those motions of the air take their first rise from vapours . now because the world is a great globe , it affordeth great store of blasts also , both the heat of the sun above , and the parching of the fire under ground , begetting various vapours . hence it is understood , why after a great fire there arises a wind presently , ( even in the still air ? ) namely , because much solid matter , ( wood and stone , &c. ) is resolved into vapours , and the air round about is attenuated by the heat of the fire , that it must of necessity spread it self , and seek a larger room . xiii winds in some countreys are certain , comming at a certain time of the year , and from a certain coast ; others are free , comming from any place . note they call these 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , which is as much to say as annuall : which are caused either by the mountainousnesse of the tract neer adjoyning , wherein the snows are then dissolved ; or to be sure some other causes , by reason of which vapours are then progenerated there in great abundance . but you must note , that those etesian winds are for the most part weak and gentle , and yield to the free winds . note there is also another kind of set wind , common to the whole world ; namely a perpetuall fluxe of the whole air , from the east to the west . for that there is such a wind . they that sail about the aequator testifie . in the seas of europe , when a particular wind ceaseth ; they say also that a certain gentle gale is perceived from the east and therefore marriners are constantly of opinion , that the navigation from east to west is speediliest performed . lastly , with us in a clear and still skie , the highest clouds are seene for the most part to be carried from east to west . therefore wee need not doubt of this generall wind , if so be any one will call it a wind . for it proceeds not from exhalations , but from the heaven , which by its wheeling round , carries the air perpetually about , swiftly above , here nigh the earth ( where the clouds are ) almost insensibly , yet under the aequator ( as being in a greater circle ) very notably . whence this probleme may be profitably noted , why the east wind dries , but the west moistens ? namely , because that being carried along with the air attenuates it the more ; but this striving against the air condenseth it . xiv a gentle wind is called aura , a gale ; a vehement wind overthrowing all it meets with procella , a tempest ; if winded into it self turbo a whirlewind . it is plain that sundry vvinds may arise in sundry places together , according as matter of exhalations is afforded here and there , and occasion to turn it self hither or thither . therefore if they flovv both one vvay , the wind doubled is the stronger ; if sideways , or obliquely , the stronger carries away the weaker with it , and there is a change of the wind which we see done often , yea daily , but when they come opposite to one another , and fall one against another , they make a storme or tempest ; vvhich is a fight of the vvinds till the strongest overcome , and is carried vvith a horrible violence bearing dovvn all before it . but contrary vvinds of aequall strength make a vvhirlvvind , vvhen neither vvill give sidevvay , but both vvhirl upvvards , vvith a violent gyration . of the sea-tide . xv the sea-tide is the daily fluxe of the sea to the shore , and refluxe back again . the sea hath its fluxes lesse unconstant then the air , for it flows onely to the shores , and back again the same vvay : and tvvice a a day it flowes up , and twice it ebbs again . the end thereof vvithout doubt is , to keepe the vvaters of the sea from putrefying by that continuall motion . but the efficient cause thereof heretofore accounted amongst the secrets of nature comes novv to be searched out of the truest grounds of naturall philosophy , and more accurate observations . xvi the cause of the sea-tide , are vapours within , wherewith the sea swelling diffuseth it self , and falling settles down again . for this tide is like to the boiling of vvater , seething at the fire ; vvhich is nothing but the stirring of the vapours raised in the vvaters by the force of the heat . for it is impossible that the vvater should not be resolved into vapours by the heat : impossible that the vapours should not seek a passage ( upvvards ) to their connaturals . yet impossible that they should have an easie passage out of the vvater , ( being that the superficies of the vvater , yea the vvhole masse thereof , being a diffused liquor like liquid glasse , hath fewer pores than the earth or wood , or a stone : ) therefore it is impossible that the water should not swel rise up , dash it self against the sides of the kettle , and at length break in a thousand openings , and give the heat dancing & evapourating a passage out , by reason of the vapour raised & multiplied vvithin , and striving upvvard : all vvhich vve see in a boiling pot . ●n the same manner the sea svvels , by reason of the vapour that is multiplyed in the bottome of its gulfes , and lifts up it self into a tumour , & of necessity spreads it self to the side , neither doth it make any thing against this , that the vvater of the sea boiling is not so hot as the water of a boiling pot . for here the vast quantity doth not admit of so great heat over such deep gulfes . for the water of a kettle heats at the bottome , bu the superficies begin to swell and turn about before they heat . xvii vapours within the sea , are chiefly generated by by the fire under ground . they referre it commonly to the caelestiall fire , the sun , and the moon . but that is likely to be as true , as that we see a pot of water to boile , set in the sun , though never so hot . for who ever saw that ? the sun may lick the superficies of the water , and so consume it by little and little , and turn it into vapour : but nothing can make it boil at the bottome , but fire put under it . therefore the cause of the vapours within the sea , must of necessity be placed underneath : namely that fire under ground , which the whole nature of inferiour things , demonstrate to be shut up there . xviii the vapours and tides of the sea are provoked by the heat of heaven , ( the sun. ) a labouring man , or a traveller , sweats easily enough by his inward heat , ( stirred up by the motion of his body ) but a great deal more easily in the heat of summer , then in winter ; and all of us sooner in a bath then else-where : the outward heat provoking the inward . in like manner the sea vapours and boiles vvithin , but yet after the harmony of the superiour fire which is from the stars . which harmony is seen also in yielding us vvater from the clouds and fountains . for in rainy vveather fountains flow more abundantly ; in dry vveather they dry something , both which god intimated , gen. . v. . and deut. . v. . now the cause is , the harmony of fire to fire ; of the caelestiall to the subterraneous , &c. as it shall elsewhere appear . xix the sea flowes twice a day , according as the sun comes and goes , for the sun ascending to the meridian , attracts the vapours of the sea , and causes the waters to be elevated and diffused : descending to the west , it suffers them to fall again . now that the waters swell again at the sun setting , and fall as he hastens to the east ; the cause is the same which in boyling pots : where the hot water is seen to boile , and to be elevated , not only in that part which is toward the fire , but also on the contrary ; but to fall again on the sides both wayes . so the sea is a caldron , which the sun ( the worlds fire ) encompassing , makes to swell up on both the opposite parts , but to fall in the intermediate parts ; so that this sea-tide following the sun , goes circularly after a perpetuall law . xx the fluxe and refluxe of the sea is varied according to the motion of the sun and moon , and the site of places . for in winter it is almost insensible , the sun but weakly raising the subterrane vapours . when the moon is in conjunction or opposition to the sun , the seas swell extraordinarily ; the force of both luminaries being joyned together to affect the inferiour things ( either joyntly or else oppositely . ) also the moon encreasing the flowings are something retarded , decreasing they are anticipated : which gave occasion to the ancients to think that it was caused by the moon alone . those sea fluxes and refluxes vary also according to the divers turnings and windings of countries and promontories , and the shorter or longer coherence of inlets with the ocean ; which causeth them to be perceived in some places sooner , in others later . but enough of the sea tide , the earthquake followes . xxi an earthquake is the shaking of the superficies of the earth in any countrey ; arising from subterrane exhalations , gathered together in great abundance , and seeking a passage out . therefore it ceaseth not till the said exhalations are either scattered through the cavities of the earth , or else break forth . xxii earthquakes are sometimes so horrible that they subvert cities , mountaines , islands , with an hideous bellowing howling , and crashing . which formidable effects cause us to suspect , that those vapours are then mixt , like to those by which thunders are caused in a cloud : and that not simply by the blast of the exhalations , but by their burning , so that they are a kinde of subterrane lightnings : yet i thought good to make mention of it here together . chap. viii . of concrete substances : namely , stars , meteors , and minerals . i a concrete thing is a vapour coagulated , endued with some form . for example , soot , clouds , snow , &c. note that this name of concrete , and concreture is new , yet fit to expresse this degree of creatures , which confers nothing but coagulation and figure . ii the primary cause of concretion of vapours is cold , which wheresoever it findeth a vapour , condenseth and coagulateth it . that appears in alembicks , where the vapour raised by heat , and carried into the highest region of it where it is cold , resolves it selfe again into water : and to that end distillours now and then wash the uppermost cap of the alembick with cold water , and make the pipes , through which the concrete liquour distils , to passe through a vessell of water . yet heat helps the concretion of things , consuming the thinner part of the concrete , and compelling the rest to harden , which we see done in the generation of metals . iii some concretes are aethereall , others aereall , others watery , others earthly . namely , because some are made in the skie , as stars : others in the air , as clouds , &c. others in water , as a bubble , &c. others in the earth , as stones , &c. every one of which come to be considered apart . iv aethereal concretes , are stars and comets . v stars are fiery globes , full of light and heat , with which the skie glitters on every side . both the ornament of the world required this , that hanging lamps should not be wanting in so lofty a palace : as also the necessity of the inferiour world , concerning which is the following aphorisme . now we reckon stars in the rank of concretes , because it is certain that they are made of matter and light . stars were produced in so great number upon very great necessity . namely , to heat the earth with a various temperature . to make the various harmony of times . to inspire a various form into the creatures . for so great variety could not be induced into the lower world , without such variety in coelestiall things . vii god placed the greatest number of stars in the highest heaven round about , that they might irradiate the earth on every side , and carry about their sphear with a rapid motion of heat . on which starry sphear take these following aphorismes . that the motion of this sphear is finished in the space of twenty four hours . and because that motion is circular , it is said to be made upon two hinges , or immoveable points ( in greek poles ) of vvhich the one is called the northern or artick pole ; the other the southern or antartick . betwixt these two poles the heaven is turned : vvith its exact globosity , describing a circle ( in the midst betwixt the two poles ) vvhich they call the aequator . now that tract , vvhere the stars arise above the earth , is called the east , or the sun-rising : the opposite to it vvhere they set , is called the west or sun-setting ; and these four angles of the world , are called the four quarters of the world , and the four cardinal points . that the stars of the highest sphear , ( commonly called the fixed stars ) are globes of vvondrous greatnesse in themselves : the greatest of them exceeding the globe of the earth an hundred and seven times : and the least of them exceeding the same globe eighteen times . that the numerable stars are found by us one thousand , tvventy tvvo : but god knovves the number of the innumerable . for the galaxias or milky way ( it is the whitest tract of heaven ) is found by accurate perspectives to be a company of very sma● stars ; and there are some other like tracts observed in heaven , though lesse , and of these the vvords of god , gen. . v. . are to be understood . that the visible stars reduced into certain figures , vvhich they call coelestiall signs in number , vvhereof about the aequator , are by a peculiar name called the zodiaque . but this zodiaque declines with one half of it toward the north , with the other part towards the south . the signes are comprehended in this distick . sunt aries , taurus , gemini , cancer , leo , virgo : libraque , scorpius , arcitenens , caper , hydria , pisces . the ram , the bull and twins to th' spring belong ; to summer crab and maid and lion strong . autumne hath scales and scorpion & the bow : goat , water-tanckard , fishes winter show that the distance of this starry sphear from the earth is found above two hundred thousand semidiameters of the earth , and a semidiameter of the earth contains of our miles . viii a very great portion of most ardent light is conglobated in the sun , so that it may seem the onely fountain of light and heat . for were it not for the sun we should have perpetuall night , for all the rest of the stars : forasmuch as at high noon , we are in darkenesse presently , if the sun be but covered . now touching the sun these following axiomes are to be noted . that it was made so great as might suffice , both to illustrate the whole world , and to heat and vaporate the whole earth : that is times greater than the earth . that it is such a distance elevated from the earth , as might serve , so as neither to burn it , nor leave it destitute . psal. . v. for it is placed almost in the middle space betwixt the starry sphear and the earth . that it is carried with a flower motion then the stars in their highest sphear . for whereas it seems to be turned about equally , as the starrie sphear is , yet it is every day left behind almost a degree , ( of which the whole circuit of the sphear hath ) whence it comes to passe , that in dayes , it compasseth the whole spear as it were going back , and after so many dayes returns to the same star again . and this we call the time of an year , or a solar year . and that it may serve all sides of the earth with its light and heat , ( to wit by turns ) that retardation is not made simply though the middest of the world under the aequator : but under the zodiack , bending to the north on this side : to the south on that side whence comes the division of the year into four parts ; ( spring , summer , autumn and winter ) and the inequality of dayes to those that inhabite without the equinoctiall . for when it declines to those on the north it makes summer with them , and the longest days , and so on the contrary . and by how much it is the more verticall to any part of the earth , it heats it so much the more , by reason of the direct incidence and repercussion of the rayes . ix and because it was not convenient that the sunne and stars should always operate after one and the same manner ( for variety is both pleasing and profitable to all nature ) there were six other wandring starres added over and besides , which running under the same zodiaque and by certain turns entring into conjunction one with another , and with the sunne might variously temper his operation upon inferiour things . these wandring starres are called planets , of which there are seven , reckoning the sun for one . x the planets therefore are the suns coadjutors in governing the world : which differ in site , course , magnitude and light . xi three of the planets saturn ( ♄ ) jupiter ( ♃ ) mars ( ♂ ) are above the sun : venus ( ♀ ) mercury ( ☿ ) and the moon ( ☽ ) below : so in a most decent manner , as it were compassing about the sides of their king. it is probable , that the stars are carried higher or lower in heavē , for the same reason as clouds in the air , or wood in water , that is , according to their different degrees of density or rarity . for as thick wood swims under the water either with all or with half of its body covered , but light wood swims on the top : and watry clouds ascend not far from the earth , but dry and barren clouds very high : so the globes of the stars are carried some higher than others according to the thicknesse of their matter and light . xii the upper plane●s are bigger then the earth , but the lower are lesser . for it is found that 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 doth equall globes of the earth . ♄ ♃ ♂ ☉ doth cōtein the part of the earth . ♀ ☿ xiii by how much the higher any planet is , and neerer to the highest sphear , so much the swifter it moveth ; by how much the lower and neerer to the earth , so much the flower . for saturn , because he is next to the eighth sphear , is rolled about almost equally with it , yet he also fals back by little and little : so that he runs through the zodiaque moving backward in the space of almost thirty years : jupiter in twelve years : mars in almost two : the sun ( as was said ) in a year : venus encompasseth the sun in five hundred eighty three dayes : mercury in one hundred and fifteen dayes : the moon because she is slowest of all , remaining behind every day deg . measures the zodiaque in ⅓ dayes . xiv the higher planets do so observe the sun , that approaching nigh unto him , they betake themselves into the highest place ; going from the sunne , they sinke lower towards the earth . and for this cause both their magnitude and their motion vary in our eyes . for when they are neerer to the earth , they seem greater ; but more remote lesser . again , the higher they are , the slower they move , and then they are called direct ; the lower they descend the swifter , so that they seem either stationary , ( keeping pace for some weeks with the same fixed stars ) or else retrograde , sometimes outstripping them in their course . xv venus and mercury depart not from the sun , unlesse it be to the sides both ways : venus degrees , mercury degrees . so that sometimes they go before the sun , sometimes they follow him , sometimes they lie hid under his rayes . note , venus when she is the morning star and goes before the sun is called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or lucifer : when she is the evening star she is called hesperus . xvi as for their light , mars is very fiery and calefactive : ♄ is pale and very frigifactive : ♃ and ♀ are of a benigne light : ☿ changeably sparckling : ☽ shines with a borrowed light onely : of which more by and by . note . that the stars and planets do not sparkle by reason of their greater distance , ( for then ♄ should sparkle more then mercury : vvhereas we find the contrary ) but by reason of their flaming . for fire or light cannot rest , therefore the polar stars , because they are least stirred with the common motion , twinckle most . xvii because the moon is near to the earth , and placed in a grosse air , she moves most slowly ; and also her body is grosse and obscure , like a globous cloud . for it is not distant from the earth above semidiameters of the earth . the moon by reason of her opacity doth not shine of her selfe , or else very weakly : but on that side that she is illuminated by the sun , on that side she shines like a looking glasse , the other halfe being obscure . note . because the moon was to rule the night , a weak light , and that but borrowed was given her , and because she was appointed to shew lesser times ( months ) a motion different from the sun was given her , that by her departure from the sun , and by her returning , she might designe the progresse of the moneths : and that it might be done more evidently , she was placed below the sun , that she might appear to us with her face enlightned after divers manners . for vvhen she runs with the sun in the same signe of the zodiack , she doth not appear to us ; because her enlightned face is turned toward the sun , but her obscure face to us . but when she is opposite to the sun , we beholding her on the same side which looketh toward the sun , see all her luminous face . lastly , in the intermediate places we see her encreasing or decreasing in light ; according as she turns her enlightned face to us , or turns it from us , by reason of the diversity of her position in respect of the sun , and us . xix when the moon , at the change , comes directly under the sun , she obscures him as to us ; when at the full , she is directly opposite to the sun , she enters into the shadow of the earth , and is her selfe obscured : and this they call the eclipses of the luminaries . hence it appears that the sun is not obscured after the same manner that the moon is . for the moon is really obscured , that is deprived of light , as being fallen into the shadow ; but the sun is not deprived of light , but is only covered from us , that it cannot as then enlighten the earth with his rayes ; therefore the earth is then more truly eclipsed then the sun. now god ordained eclipses that we might understand , that all our light is from the sun. that the magnitude of the luminaries , and of the earth might be found out . to finde the true longitude of countries ; but that belongs to astronomers , this last to geographers . of comets . xx comets are accessory stars , which somtimes shine , and go out again : for the most part with tayles , or busbes of hair . we reckon them to the heaven and stars , not to the air and meteors : because they are not generated in sublunary places , ( as aristotle thought ) but in the highest heaven , even above the sun : which their motion , swifter always then the moon it selfe . their parallax , lesse then the moons , somtimes none at all , do shew . xxi comets are not vapours kindled ; but a reflexion of the suns light , in vapours so far elevated . the first is easily proved . for if a comet were a vapour kindled , it could not last halfe an hour . ( for nothing can be kindled but a sulphury matter , but that is consumed in a moment , as it appears in gun-powder , lightning , a chasme , a falling star , &c. ) but histories relate that comets have lasted three years . the second is shewed , because comets cast a taile from the sun , as the moon doth a shadow ; ( for those dry vapours are not an opacous body , like to the moon , but semidiaphanous . ) they are eclipsed ( as campanella testifies ) by the shadow of the earth , as well as the moon : which vvould not be , if they burned with their own fire . n. w. that which is reported of a fulphureous matter , or stone , which fell from a burning comet , if it be true , it is to be thought , that it was made of some fiery meteors , not of a comet . xxii the ends of comets are , that it may appear ; that the whole heaven moves , not the stars only . that it is liquid and transmeable , not hard like chrystall . that vapours ascend so high , and that there are mutations every where in this visible world . vapours , i say , whether exhaling from this our inferiour world , or from the supercelestiall waters . for there is nothing to the contrary , why we should not hold , that they also exhale , and are spread abroad into the thinner region of the stars . of aëriall concrets , that is , meteors . xxiii by reason of the perpetuall confluxe of exhalations in the air from all the elements , many things are daily there concreted , but of small continuance . for the air is full of exhalations , even when it seemeth clear . for it cannot be so pure here near the earth , but it will have something watery , oily or salt alwayes admixt with it . things concrete of these were anciently called meteors , because they are made on high : for 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 signifies high . xxiv of humid exhalations are made watery meteors : fiery of dry . xxv watery meteors are , mists , clouds , rain , hail , snow , dew , frost . we must see them every one apart , how they are made . xxvi a mist is a watery exhalation half concrete , which being that by reason of its density it cannot elevate it selfe , creeps on the ground . xxvii a cloud is a gathering together of thin vapours , and elevated upward , in the highest of the air . they are gathered together most of all over the sea , and standing waters , because there most exhalations are made , and from thence they are driven through divers parts of the world by the windes , and increased with exhalations arising elsewhere . hence in every region , rain comes , most often from that part , which lies nearest to the sea ; as with us from the west . xxviii rain is the resolution of a cloud into water , and the falling of it by drops . n. that resolution is alwayes made by the condensation of the vapour , but there is not alwayes the same efficient cause of its condensation . for sometimes cold condenseth a vapour , as in the head and pipe of an alembick ( which must needs be cooled ) we see : sometimes the very compression it selfe , or conspissation , as it is plain in the roof of baths , and the cover of a boiling pot . but neither of these causes is wanting to beget rain : being that the middle region of the air is cold , and the cloud being pressed together by the vapours alwayes ascending , must of necessity be dissolved . and this is the cause , why the burning heat of the air is a fore-teller of rain : because then it is certain that the air is thickned . n. . that rain is better for fields and gardens then river water , because it hath a kind of a fatnesse mixt with it , from the evaporations of the earth , minerals , plants , and animals , wherewith it gives the earth a most profitable tincture . n. sometimes wormes , small fishes , frogs , &c. fall with the rain , which , as it is very likely , are suddenly generated within the cloud , of vapours gathered together of the same nature , by virtue of a living spirit admixt therewith ; as in the beginning , at the command of god , the waters brought forth creeping things and fishes in a moment . xxix hail is rain congealed . for when the sun beams in the greatest heat of summer , have driven away all cold from the earth into the middle region of the air , it comes to passe that that vehement cold doth violently harden the drops of rain passing through them , and forces them to turn to ice : and therefore haile cannot be procreated in winter , the cold abiding then near the earth , not on high . xxx snow , is a resolution of a cloud into most small drops , and withall a thickning of them with a gentle cold . n. it falls only in winter : because the vapours are not elevated by the weak rayes of the sun , so far as the middle ( that is the cold ) region ; here then near the earth , the resolution is made in a milder cold , and withall the congelation is very mild . the whitenesse of the snow is from the conjunction of the parts of the water : the same comes to passe in broken ice , and in the froth of water . xxxi dew is a thin vapour ( or else the air it selfe ) attracted by the leaves of plants , and with their coldnesse condensed into water . for it is no where , but upon plants ; and that in the heat of summer , when the plants are colder then the air it selfe . now this turnes to the great benefit of the plants ; for by that means they are moistned , at the very driest time of the year . and therefore they are produced also in those countries which know no rain . xxxii frost is congealed dew . therfore there is none , but in winter , when cold reigns by reason of the suns absence . of fiery meteors . fiery meteors are those , which arise from fat fumes , kindled in the air : the principal kinds of which are seven ; a falling star : a flying dragon : lightning : flying sparks : ignis fatuus : a torch : and ignis lambens . xxxiii a falling star is a fat and viscous fume , kindled ( by an antiperistasis , that is an obsistency of the cold round about ) at the upper end of it , the flame whereof following its fuell is carried downward , till it fail also and be extinguished . for they are to be seen every clear night , in winter more then in summer : and you may see the like spectacle , if you kindle the fat fume of a candle put out with another candle put to it above . this falling star is made of a grosse vapour ; and by reason of its grossenesse hanging together like a cord . therefore it burns so violently , that falling upon a man it burns through his garment . look which way it tends with its motion , it foretels wind from that part . xxxiv a flying dragon , is a long , thick , fat fume , elevated in all its parts : for which cause being kindled , it doth not dart it selfe downward , bnt side-wayes like a dragon , or sparkling beam . this meteors is not so often seen : and therefore they that are ignorant of the naturall causes , think that the divell flies . xxxv lightning is fire kindled within a cloud , which flying from the contrary cold , breaks out with an horrible noise , and for the most part casts the flame as far as the earth . the world is the alembick of nature , the air the cap of this alembick : the sun is the fire : the earth , the water , minerals , plants , &c. are the things which being softned with this fire , exhale vapours upward perpetually . so there ascend , salt , sulphury , nitrous , &c. vapours , which being wrapped up in clouds , put forth various effects , for example , when sulphury exhalations are mixt with nitrous , ( the first of a most hot nature , the second most cold ) they endure one another so long , as till the sulphur takes fire . but as soon as that is done , presently their followes the same effect as in gun-powder , ( whose composition is the same of sulphur and nitre ) a fight , a rapture , a noise , a violent casting forth of the matter . for thence it is that a viscous flaming matter is cast forth , which presently inflames whatsoever it touches that is apt to flame , and smiting into the earth , it turnes to a stone , and being taken out after a time , is called a thunder-bolt . xxxvi flying sparks are a sulphury fume scattered into many small parts and kindled . it is seldome seen as likewise those that follow . xxxvii ignis fatuus , is a fat and viscous fume , which by reason of its grossenesse , doth not elevate it selfe far from the earth , and being kindled , straggles here and there , leading travellers sometimes out of their way , and into danger . xxxviii a torch is a fume like it , but thin , and therefore elevated upwards : which being kindled . burnes a while like a candle or lamp . xxxix ignis lambens , is a fat exhalation coming from a living body , heated with motion , and kindled at its head , or near about . it sometimes befalls men and horses , vehemently breathing after running , that the ardent vapours sent forth , are turned into flames . of appearing meteors . appearing meteors , are the images of things in clouds , variously expressed by the incident light : of which sort there are observed seven : chasma , halo , parelius , paraselene , rods , colours , the rainbow . xl chasma ( a pit ) is the hollowness of a cloud , making shew of a great hole . it it by reason of a shadow in the midst of a cloud , the extremities whereof are enlightned . you may see the like almost in the night by a candle , on a wall , which hath any hollownesse in it , though it be whitish . xli halo ( a floor ) is a luminous circle , when the vapours underneath the sun , or moon , are illustrated with the rayes of the luminary . you may see the same by night in a bath , or any other vaporous place , about a burning candle . it is oftest seen under the moon , because the sun with his stronger rayes either penetrates or dissipates the cloud . xlii parelius ( a false sun ) is the representation of the sun upon a bright cloud placed by its side . after the same manner , if you stand upon the opposite bank of a river , you shall see two suns ; the one , the true one in heaven , the other reflected in the water . there are sometimes three suns seen , if two of those clouds are at once opposed to the sun ; and our sight . xliii paraselene ( a false moon ) is the image of the moon expressed after the same manner , upon a collaterall cloud . xliv rods , are beams of the sun covered with a cloud , yet shining through the thin cloud , stretched towards the earth like rods . xlv colours are they that appear divers in a cloud , according as it is after severall manners turned toward the sun and us ; so that the cloud seems somtimes yellow , somtimes red & fiery . xlvi lastly , the rainbow is an halo opsite to the sun or moon , in a dewy cloud , reprepresenting a bow of divers colours . for there are lunar rainbows also . now that the rainbow is an appearing meteor , is plain , if it be but from hence , that it comes and goes backwards and forwards with the eye of the beholder ; and so it appears to be in severall places , to those that behold it from severall places , even as the image or brightness of the sun , to those that walk up and down on the shore . i say that it is a meteor like to an halo , because it is alike circular . and as in the halo , the center of the luminary , the center of the lightsome circle , and the center of our eye are in one right line , so in a rainbow : onely that in the first the luminary and the eye are the extreams , the halo in the middest : here the luminary and the bow are the extreams , and the eye in the middest . now there doth not appear a whole circle in the rainbow , because the center of it to us fals upon the earth , and so the upper halfe of the circle only appears . if any one could elevate himselfe into the cloud , or above the cloud , without doubt he would see the whole circle of the rainbow . hence also the reason is evident , why at the suns rising or setting there appears a whole semicircle elevated right up towards heaven ; but when the sun is high , it appeares low . lastly , why there can be none at all when the sun is verticall . the lunar rainbowes are onely pale , as an halo : the solar shewes forth most fair clouds , from a stronger light diversly reflected from a thousand thousand drops , ( of the melting cloud : ) the colours being coordinate , as is to be seen in a chrystalline prisme : and certainly the rainbow was given even for this , that we might learn to contemplate the nature of colours . there is also a contrairis , namely when the rainbow reflects again upon another cloud underneath ; and therefore it is lesse and of a weaker colour , and the order of the colours inverted ; so that the highest is lowest , as in a glasse the right side answers to the left side , &c. but of meteors enough . of watery ( oncretes . xlvii watery concretes are : a bubble , foame , ice , and severall appearances in the water : also the saltnesse of the sea , spring waters , and medicinall waters . xlviii a bubble is a thin watery skin , filled with air . it is made when a small portion of air thrust down below the water is carried upwards : which the water , being somwhat fatter in its superficies , suffers not presently to flie out , but covers it with a thin skin , like a little bladder . by how much the more oily the water is , by so much the longer the bubbles hold : as it is to be seen in those ludicrous round bubbles , which boyes are wont to blow out of water and sope , ( which flie a great while through the air unbroken . ) from the bubble we learn , to what a subtilty water may be brought . for the skin of a bubble is a thousand times thinner then the thinnest paper . xlix foame is a company of very small bubbles , raised by the sudden falling of water into water . the beating of the water into small parts causes whitenesse in the foam ; even as ice , waxe , pitch , and other things are whitish when they are beaten . the durability also of the foam is more in an oily liquour , as in beer , &c. l ice is water hardened together with cold . li watery impressions are images of clouds , of birds flying over , of men , of trees , and of any things objected . it is known , that water is the first mirrour , receiving the images of all things : which is by reason of the evennesse of its superficies . for light coloured with things falling upon the water , cannot ( as it comes to passe in another body of a rough superficies ) be dispersed , but by reason of its exceeding evennesse is intirely reflected , and presents it selfe whole with that image to the eye of the beholder . this is the ground of all mirrours . but let us come to reall concretions in the water . lii the saltnesse of the sea , is from the subterrane fire , which heating a bituminous matter , spreadeth salt exhalations through the sea . saltnesse something bitter , with a kind of oleosity was given to the sea . that the waters might not putrifie . for the more convenient nutriment of fishes . for strength to bear the burdens of ships . now the sea is salt , not ( as aristotle thought ) by reason of the sun beams , extracting the thinner parts of the waters , and scorching the rest . ( for our fire would do the same , and the sun in lakes and pooles , neither of which is done : yea , by how much the more , salt water is heated with our fire , the salter it is ; but fresh water is so much the fresher ) but by reason of the heat included within the bowels of the earth , and of the deep ; which when it cannot exhale , it scorcheth sharply the humour that there is , so that it turnes to urine : the very same we see done in our own body ( and all living creatures ) for urine and sweat are alike salt . liii spring waters are made of vapours condensed in the cavernes of the earth ; after the same manner , as drops are gathered together upon the covers of pots . it is certain that under the earth there lies a great deep , gen. . . that is a mighty masse of waters , diffused through the hollows of the earth ; which that it joynes with certain gulfes of the ocean , this is an argument that the depth of the sea in some places is altogether insearchable . therefore as vapours ascend out of the open sea into the air , which being resolved into drops distill rain : so the subterrane waters , being attenuated by the subterrane heat , send forth vapours , which being gathered together in the hollowes of the earth , and collected into drops , flow out which way [ passage ] is given them . and this is it which the scripture saith , all rivers enter into the sea , and the sea runneth not over : unto the place from whence the rivers come they returne , that they may flow again . eccles. . v. . whence it is understood why springs yield fresh water , though they come from those bitter , and salt waters of the sea ? namely , because they come by distillation to the spring head . for they say , that the sea water being distilled ( that is resolved first into vapours , then into drops in an alembick ) looseth its saltnesse : by the same reason then the deep under ground , evaporating salt waters sendeth them fresh out of fountains neverthelesse . and what need words ? for clouds gathered of the vapours of the sea : send down fresh showers . s● how excellently the truth of things agree with it selfe still . liv medicinall waters are made of the various tinctures of the metals and juices of the earth , ( from which they receive the virtue 〈◊〉 healing and savour . ) for example , hot waters or baths , a● made of bitumen burning within : therefore they exhale sulphur manifestly ; b●● sharpish waters relish of iron , coper , vitrio●allom , &c. of which earthly concretes it wil● be now time to speak . of earthly concretes , which are called minerals . lv minerals are earthly concretes begotten of subterrane vapours ; as clods , concret juicesî metals , and stones . these are called minerals from the hebrew 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 as if you shonld say from the earth . they call them also fossiles , because they are digged : that all these are begotten of subterrane vapours , and subterrane fire , appears by the example of our body : wherein bloud , choler , flegme , melanlancholy , urine , spittle , fat , flesh , veins , nerves , membranes , gristles , bone , &c. yea , the stone and gravell , are made of the vapours of food concocted and digested as : shal be seen hereafter . now as these parts of ours are formed within the body by the heat included ; so minerals are generated in the bowels of the earth , not elsewhere . for the earth with its most deep passages and veins winding every way , where infinite vapours are generated , and perpetually distilled in a thousand fashions , is that great work-house of god , wherein , for the space of so many ages , such things are wrought , as neither art can imitate , nor wit well find out . lvi clods are digged earths , infected only with fatnesse , or some colour , and apt to be soaked , as clay . marle . chalk . red earth . paintings , or painters colours , ( as lake , vermilion , oker , azure , or blew , verdigrease . ) fullers earth in greek , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . medicinall earth , as sealed earth , lemnian , armenian , samian , &c. these colours seem to be nothing else , but the soot of the subterrane fumes , variously distilled ; and those earths , nothing else but a various mixture of liquors distilled also variously , and brought to such or such a quality . lvii concrete juices , are fossiles indued with a savour , or some sharp virtue , apt to be dissolved , or kindled ; as sulphur , niter , salt , allome , vitriol , arsenick , ( which painters call orpiment ) antimonie or stibium , & such like . n. those juices seem to be nothing else but the cream of subterrane liquors variously distilled . lviii metals are watery fossiles , apt to be melted , cast , and hammered : as gold , silver , brasse , ( or copper ) iron , tin , lead , quick-silver . n. . that they are progenerated of fire , this is enough to testifie , that they are oft times taken hot out of the veines , so that the touch will not endure them . for in winter when all herbs are white with frost , those which grow over the veins , admit of no frost , because of the hot exhalation within hindering concretion , so also trees , by the blewnesse of their leaves , shew the veines of metals . now that metals are made of vapours , this is an argument that they are wont also to be procreated in the very clouds . for examples are not unknown , even in our age of bodies of brasse , or iron , of no small weight falling from heaven . that metals are made of watery vapours their liquabilitie shews ; now they are coagulated by virtue of salt . therefore the drosse of iron is salt and bitter . quicksilver alone is alwayes liquid , never consistent ; as a perpetuall witnesse of the watery nature of metals . other metals swim upon it , because it hath the most compacted substance of all , gold only excepted : which therefore it receives only into it selfe . whether metals differ in their species , or only in degree of purity and hardnesse , and in heat , we leave now in suspense . lix stones are earthly fossiles , hardly compacted , apt only to be broken in pieces . that stones are earth coagulated with water and fire , bricks and pots teach us ; for here art imitates nature . yet the severall formes of stones shew , that they are not earth simply concrete , but a masse concrete of divers most grosse earthly vapours , with a various temperature of humours . lx stones are either vulgar , or precious . lxi a vulgar stone is earth most hardly compacted : the principall kinds of which are seven . the gravell stone , the milstone , the pumice-stone , the flint , ( to which i refer the smiris wherewith glasse is cut , and iron polished the whetstone , and the touch stone , ( or lapis lydius ) the marble and the loadstone . n. every kind have their differences again . a great stone is called saxum or a rock , a little one , gravell and sand . most mountains are stony , ( and yield metals ; ) because the subterrane fire ( on the third day of the creation ) swelling the earth here made it self many channels and passages , breathing through which , it doth variously exhale , melt , mix and boile the matter : which is not done so copiously under plains . lxii pretious stones are are called gems , because they are the gums of stones sweating in the bowels of the earth . hence comes their clearnesse and brightnesse , that is to say , from their most thin● and accurate straining , even more then in the gums of trees ; for wood hath loose● pores then stones . lxiii all gems are transparent , and pellucid : but some onely transparant , as these three ; the diamond , the chrystall , the beryll● others coloured with all , and those● ( according to the diversity of their colours ) of sve●● sorts . bright and burning ; the carbuncle the chalcedon , the chrysolite . yellow ; the jacinth and topaze . green ; the emerald , and the turquois . red or purple : the rubie and the granate : but the carnelous and the onyx are more pale . skie-coloured ; the saphir , and the amethyst , black ; the morion changeable ; as the jasper , the agat , the chrysoprase . n. . that chrystall is never found unlesse it be hexagonall , which is the miracle of nature . and that it is growes in arched cels under ground , dry and closed , where the wind enters not for some years , hath been experienced at kings itradeck in bohemia , anno . for elegant chrystals were found hanging from the stones of the arches , like isicles of an exact hexagonall forme , but in the silver mines of catteberge , there are found far more . of other gems we have nothing to say in particular . n. . stones that are wont to grow in some living creatures , are usually reckoned amongst precious stones : as the pearl , in sea shell fishes : the bezoar . the chelidonius , the alectorius , the bufonites , &c. also corall , and amber . but these two , are to be referred rather to the following chapter . lxiv the virtue which is in minerals , is called their naturall spirit : of which there are so many formes , as there are species of minerals . for there is one spirit of salt , another , of vitrioll , loadstone , and iron , &c. which distillers know how to extract . chap. ix . of plants . thus much of concretes : here follow plants which beside their figure have life . a plant is a vitall concrete , growing out of the earth : as a tree and an herb . some concretes ( stars , meteors , minerals , ) want life , and lie or tarry where they were concrete : but plants endued with an inward vigour , break out of the earth , and spread themselves in plano : whence also they were called plants . ii plants are generated , both to be an ornament to the earth , and to yield nourishment , medicine , and other uses to living creatures . for what a sad face the earth would have if it were not cloathed every year with those diverse coloured tapistries of herbs , we have sufficient experience in winter , and whence should living creatures have food , medicines , and pleasures , if we were destitute of the roots , leaves , seeds and fruits of plants ? not to speak of the commodity of shade , and of the infinite uses of wood . iii the essentiall parts of a plant are , the root , the trunk ( or stalk ) and the branches or leaves . n. w. the elements , vapours , concrete things , consisted only of similar parts : for every part and particle of water , earth , vapour , a cloud , iron , &c. is called , and is water , earth , vapour , a cloud , iron , &c. but more perfect bodies , ( of plants and living creatures ) do consist of dissimular parts that is members ) every one of which hath both its office , and its name , differing from the rest . for example . in a plant , the root is the part sticking in the ground , and sucking in the juice of the earth : the truk , ( or stalks ) attracting the juice , concocting it : and sending it to the upper parts : the boughes and branches , are twigs , distributing the juice yet better concocted , to make seed and fruit : the leaves are the coverings of the fruits and boughes . iv the spirit of a plant is called a vegetable , or vitall spirit ; which puts forth its virtue three manner of wayes ; in nutrition , augmentation , and generation . for here that universall spirit , ( the spirit of life , ) begins more manifestly to put forth its virtue , preparing a portion of matter so softly to its turn , that it may have it tractable to perform the offices of life : and is therefore called vitall in plants , namely , because of its more manifest tokens and effects of life . they call it also the vegetative soul v nutrition is an inbred virtue in a plant , whereby sucking in juice fit for it , changeth it into its own substance . for because the encompassing air dries up every body , and the heat included in a living body doth also feed upon the inward moisture ; it were impossible that a plant should not presently fade away , unlesse new matter and vigour were continually supplyed with fresh nourishment , to make up that which is lost . and to this end every plant hath a body , either hollow , or else pithy , and porous , that the nourishing vapour may passe through and irrigate all the parts ; yea whatsoever is in a plant , even the very haire or downe , is hollow and porous . therefore in a man , the head is eased , when the haire is cut ; because the fuliginous vapours of the braine , or the superfluities under the skin , do the more easily evaporate . for the same cause every plant rests upon its root , that sucking the moisture of the earth through the strings thereof it may be nourished : therefore it perisheth when it is pluckt up . the humour then , or fat juice of the earth , is a fit nourishment for plants : not dry earth , because it cannot passe through the strings and pores of a plant ; nor water alone , because it cannot be concrete into a solid body . therefore the moisture of the earth which is a mixture of mercury , sulphur and salt nourisheth plants vi augmentation is a virtue of a plant , whereby it increaseth also by nourishing it self , which we call by a common terme growing . it is pleasant to contemplate what it is to grow , and how it is done now it is easily found out by the doctrine of motions already delivered . for first , when the spirit included in the seed , begins to diffuse it self , and to swell by reason of the heat that is raised , the thin shell of the seed must of necessity break : by the motion of cession . and because every body is moved towards a greater company of its connaturals , that vapour comming forth when the seed is warmed , tends towards heaven ; but because the matter of the seed is fat and glutinous , the vapour being infolded therein carries it upwards with it , and brings it forth out of the earth , and this is the originall of the stump and boughs now because that the outside of the plant hindereth the vapours ascending , there is a strife , and heat is raised , whereby the superficies of the small body is by little and little mollified , that it may yield and rise up . and this is done every day when the sun is hot : but the tender parts which grow up are condensed and made solid with the cold of the night : by which successions of day and night the plants take increase , all spring and summer long . now look how much moisture is every day elevated upward by the stump , so much again succeeds it by the motion of continuitie . least there should be a vacuum . but because every body loves an aquilibrium , and plants own their center in the joynt of the stump and root , it comes to passe by the motion of libration , that as much as the boughs spread themselves upwards , so much the roots spread downwards or side-wayes . now there is a question , why when a leafe or a bough is pluckt off , yea when the stock is cut asunder , the spirit doth not exhal● , but containes it self , und growes stills ? answer because the spirit hath its proper seat fixed in the root , which it doth not forsake , though a passage be open through a wound received : nay more , fearing discontinuity , it gathers and conglobates it self , when it perceives an opening and danger of dissipation . because the wound is presently overspread with the moisture of the plant , which being hardened with the outward cold , covers the wound as it were with a crust , and prohibits a total expiration . vii . generation is a virtue of a plant , whereby it gathers together and conglobates its spirit into a certain place of it ; and makes a seed or kernell , ( from which the like plant may afterwards grow . ) the spirit of the plant foreseeing as it were , that it shall not always have matter at command , which it may vegetate , turns but a part of it self into the nourishment of the plant , and gathers together the rest into a certain place ( usually in the tops of plants ) and makes a seed or kernell . now the seed ( kernell or graine ) is nothing else , but the image of the whole plant , gathered together into a very small part of the matter ; from whence , if need be , the same plant may be produced again : as we see done . n. w. that herbs are bread neverthelesse without seed , by virtue of the spirit infused into the elements . the command of god proves , gen. . v. . let the earth bring forth , &c. which is yet in force . experience . for if you uncover the earth beneath all roots and seeds , yet in the years following vvhen it hath been somewhat oft watered vvith rain vvater , you shall see it bud forth . vvhich is a notable argument of the spirits being diffused every where , but especially descending with the sun and raine . viii . the outer , and inner bark , leaves , shells , downe , flowres , prickles , &c. are integrating parts of plants : serving to defend them , and preserve their seeds from the injurie of heat and cold . ix . the kernels are for the most part encompassed with a pulp for their thinner nourishment , and to defend them from injury , but yet this pulp when it is come to ripenesse , serves for food to living creatures ; as it is to be seen in apples , peares , cherries , plummes , &c. x. the proprieties of plants are , varietie , heat , and tenacity of their spirit . xi . the variety of plants is so great , that the number can scarce be counted by any means . the natural spirit in meteors and minerals makes certain species , and those easie to be counted , ( as we see ; ) but the vitall spirit doth so diffuse it self , that the industrie of no man is yet sufficient , to collect the the species of herbs , and trees . xii . the cheif kinds of plants are herbs , trees , shrubs . xiii . an herb is , that which growes and dies every year xiv . a tree is , that which rising up on high , growes to wood , and continues many years . xv. a shrub is of a middle nature ; as the alder , the vine . n. w. . some trees live for many ages : to wit , such as have a compacted and glutinous substance , as the oak , the pine , &c. vvatery and thin plants , do soon grow and soon vvither ; as the sallow , &c. some lose their leaves every year , namely , those that have a vvatery juice : others keep them as trees of a rozenous nature . trees are either fruitful or barren : the first bear either apples or nuts , or fruit like unto pine apples , or berries . porositie and airynesse is given to the vvood of trees , by reason of which they do not sinke , and that . that they might take fire . that they might the more easily be transported any vvhither through rivers . that ships might be made of them . also clamminesse or indissipability vvas given them , that they might serve for the building of houses : for vvhich end also their talnesse serves . other differences of plants may be seen else vvhere . xvi . all plants are hot by nature ; but in proportion to our heat , some are called cold . for generation is not done but by heat ; but that vvhich is below the degree of our heat , seemes cold to us . as for hemlock , opium , &c. they do not kill vvith cold , but vvith the viscosity of their vapours , vvhich fill up the cavities of the brains , stop the nerves , and so suffocate the spirit : the same may be said of all poisonous things . xvii vitall spirit ( as also naturall ) holds so fast to its matter , that it scarce ever forsakes it . this is demonstrated ( besides that we see the spirit every year to be driven by the cold of winter out of the stocks , and to be hidden in the root : and to put forth it selfe again at the beginning of the spring ) by four examples . that how ever the matter of fruits or herbs be vexed , yet the spirit conteins it selfe : as it is to be seen in things , smoaked , tosted , roasted , soaked , pulverized , &c. which retein their virtue . that being driven out of the better part of the matter , by the force of fire , yet it sticks in the portion that is left , and there it is congregated , and inspissated ; so that it suffers it selfe to be thrust together into a drop , or a little poulder , rather then forsake the matter : as it appears in distilled waters , which therefore they call spirits . that when its matter is somewhat oft distilled and transfused into divers formes through divers alembicks , yet it doth uot fly away . for example , when a goat or a cow eats a purging herb , and the nurse drinks her milk ( or the whey of her milk ) it comes so to pass , that the infant that sucks her will be purged . and which is more , it doth not onely retein a virtue of operating : but also of augmenting it selfe , and forming a creature of its kind : which may be shewn by two examples . sennertus relates , that hieremy cornarius caused a water to be distilled in june , anno . and that in the moneth of november a little plant of that kind was found at the bottome of the glasse , in all points perfect . but quercetanus writes that he knew , a polonian physician , that knew how to pulverise plants so artificially that the poulder as oft as he listed would produce the plant . for if any one desired to have a rose or a poppy shewed him , he held the poulder of a rose or a poppy inclosed in a glasse over the candle that it might grow hot at the bottome ; which done , the poulder by little & little raised it self up into the shape of that plant , and grew , & represented the shape of the plant , so that one would have thought that it had been corporeall : but when the vessell was cold sunk again into poulder . who sees not here that the spirits are the formers of plants ? who sees not that they inhere so fast in their matter , that they can as it were raise it again after it is dead ? who sees not that the spirit of a minerall or a plant is really preserved in the forme of a little water , oile , or poulder ? thus the eternall truth of that saying is mainteined . and the spirit of god moved it selfe upon the waters . as for the spirit of a living creature , whither it may be preserved after that manner , and raised up to inform a new body , we leave it to be thought of : purposing neverthelesse to speak something of it towards the end of the next chapter . chap. x. of living creatures . thus much of plants ; here follow living creatures . i a living creature is a moving plant , endued with sense : as a worm , a fish , a bird , a beast . for if a stone or an oak could move it self freely , or had sence , it would be a living creature also . ii the principall difference betwixt a living creature and a plant , is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , that is a free moving of it selfe to and fro . for the better to expresse the power of the spirit of life , gods vicar in creatures , it was needfull that such bodies should be produced , which that spirit inhabiting , might have obedient unto all actions . now seeing that the ground of action is motion , bodies were to be framed , which might performe a free motion , and these are called animalia or animantia , living creatures , from the soul which powerfully evidences life in them . therefore mobility is in all living creatures , but after divers manners . for some move only by opening and shutting , not stirring out of their place ; as oisters and cockles . others creep by little and little , as snailes , earth-wormes , and other wormes : some have a long body which creeps with winding it selfe about , as snakes : some have feet given them , as lizards , beasts , birds : but these last have wings also to flie through the air . which fishes do imitate in the water , performing their motion by swimming . iii the moving principle in a living creature is the vitall soul : which is nothing else but the spirit of life , thick and strong , mightily filling , and powerfully governing the bodies which it inhabiteth . iv now because a voluntary and a light motion cannot be performed , but in a subtle matter , living creatures have bodies given them far more tender then plants , but far more compound . for they consist of spirit , flesh , blood , membranes , veins , nerves , gristles , and lastly bones , as it were props and pillars , lest the frame should fall . understand this in perfect living creatures . for more imperfect living creatures in which we contemplate onely the rudiments of nature , have neither bones , nor flesh , nor bloud , nor veins : but onely a white humour , covered with a skin or crust , as it were with a sheath , which the spirit included doth stir or move ; as it appears in worms , snails , oisters , &c. but to perfect living creatures . that they might have a more subtle spirit , bloud and brains were given . and that these might not be dissipated , they had vessels and channels given them , veines , arteries , nerves , that a living creature might be erected , bones were given him . and left the bones , as also the veins , arteries , nerves , should easily be hurt , all was covered either with fat or flesh . and that the members might move , tendons and muscles were interwoven throughout . and least in moving the bone , the bones should wear one against another , & cause pain in the living creature ; a gristle which is a softer substance , being as it were halfe flesh , was put between the joints . and lastly ; that the frame might hang firmly together in its composure , it was compassed with a hide , or skin , as also all the members with their membranes . therefore a living creature consists of more similar parts then a plant : but of far more dissimular parts or members : of which it followes . v the bodies of living creatures were furnished with many members : as with diverse organs for diverse actions . the head indeed is the principall member of a living creature , wherein the whole spirit hath its residence , and shews all its force : but because a living creature was intended for divers actions , it had need of besides . vivifying organs , supplying the living creature with heat , life , and motion : that is , brains and heart . moving organs , that is , feet , wings , feathers , &c. and left one thing should run against another , or fall into precipices , it was necessary to furnish them with sight ; also with a quick hearing and touch . lastly , because the earth was not to supply nutriment immediately to a living creature , ( as to a plant fixed in the earth ) but it was left them to seek : there was need of smelling and tasting , that they might know what was convenient to their nature . hence eyes , ears , nostrils , &c. now because a living creature , was not to be fixed in the ground with a root , because of his free motion , more perfect organs of nutrition were requisite : for that cause there was given him a mouth , teeth , a stomack , a liver , a heart , veins , &c. and because they were not to spring out of the earth as plants , by reason of the same motion to and fro . divers sexes were given them to multiply themselves , and distinct genitall members . and because living creatures were to be alwayes conversant with others of their own , or of a divers kind , they had need of some mutuall token , even in the dark : they had a tongue given them to form sounds . lastly , because it could not be , but that a living creature should sometimes meet with contraries , they had as it were shields and armes given them . hares , bristles , scales , shels , feathers : likewise horns , clawes , teeth , hoofs , &c. vi therefore the whole treatise concerning a living creature , is finished in the explication i of the nutritive faculty . ii of the vitall . iii of the sensitive . iv of the loco-motive . v of the enuntiative . vi of the defensive . vii and lastly , of the generative . for he that knoweth these seven , knowes the whole mysterie of nature in living creatnres . for whatsoever is in the body of a living creature , serveth those faculties : if it do not serve them , it is in vain , and maketh a monster . it is to be observed also that the first three faculties are governed by so many spirits . the nutritive faculty by the naturall spirit , the vitall by the spirit of life , the sensitive by the animall spirit : the other four by those three spirits joyntly . of the nutritive faculty . vii every living creature standeth in need of daily food , to repair that which perisheth of the substance every day . for life consists in heat . and heat , being that it is fire , wants fuell : which is moist , spirituous , and fat matter . heat in a living creature being destitute of this , sets upon the solid parts , and feeds on them . and hence it is that a living creature , as well as a plant , without nourishment pines away , and dies . but if it be sparingly fed , it therefore falls away , because the heat feeds upon the very substance of the flesh . viii that nourishment is convenient for a living creature , which supplies it with a spirit like its own spirit . for seeing that life is from the spirit , the matter of it selfe doth not nourish life , but a spirituous matter . and indeed the spirit of the nourishment must needs be like the spirit of the living creature . therefore we are not nourished with the elements , as plants are ; for as much as they have only a naturall , not a vitall spirit ; but we are nourished with plants , or with the flesh of other ●iving creatures , because those afford a vitall spirit . nay further , there is a particular proportion of spirits , by reason of which a ●orse chuseth oates , a swine barley , a wolfe flesh , &c. nay , an hog hath an appetite to mans excrements also , because it yet findeth parts convenient for it . ix nourishment turneth into the substance ●f that which is nourished . that appears because he that feeds on dry meats , is dry of complexion : he that feeds on moist , is flegmatick , &c. because , for the most part a man reteins the qualities of those living creatures on whose flesh he feeds , as he that feeds on beefe is strong ; he that feeds on venison , is nimble , &c. if any one have the brains of a cat o● a wolfe given him to eat , he partakes the phantasies of those living creatures , &c. x nutriment must needs be assimilated that it may turn into the substance of a living creature . for a thing is neither applied well , no cohereth commodiously with that which is unlike to it ; much lesse that one should turn it into the other . therefore flesh 〈◊〉 bone is not immediately made of meat 〈◊〉 drink : but by many gradations , as it sha● appear . xi assimulation is made by the transmitation of the nourishment taken so oft iterat● till it come to the liknesse of the substance no●●rished . it is well known out of the metaphysick● that all action tends to this , that the pa●●●ent may become like to the agent , whic● is every where evident in naturall thing● but especially in the nourishment of bodies . for whatsoever is taken in , of whatsoever colour or quality , is wrought so●● length , that it becomes like to that which is nourished , and is applyed to its substance : which should be diligently marked in that which follows . xii the principall transmutation of the nourishment , is by progeneration of the four vitall humours , bloud , flegme , yellow choler , and black . for the nourishment received , being that it is tempered together ( as all the bodies of the world are ) of the four elements , is resolved in the body of a living creature into four again ; the fattest part of it is turned into bloud : a part into spittle , or flegme , a part into yellow choler , or choler ; a part into black choler , or melancholy : melancholy by its grossenesse represents the earth : flegme , water : bloud , air : choler , fire . but they differ in colour and in savour ; for melancholy is black and bitter ; flegme , white and without taste : bloud , red and sweet : choler , yellow and bitter . now it is to be noted , that amongst these four , bloud is most copiously generated , because it conteins the very substance of the nourishment : to which yellow choler addes onely a more easie penetrating through all : but black choler fixeth it again , and applieth it to the members : lastly , flegme tempers the acrimony of them both , lest they should corrode with penetrating and fixing , and gently agglutinates the bloud to the members : and hence it is that physicians also with the vulgar speak oft of the blood , as if it were the only food of life . xiii the progeneration of vitall humours is done by concoction . for concoction doth alter the matter by the force of heat . xiv concoction in a living creature is done after the same manner as distillation in alembicks : namely , by heating of the matter , and resolution of it into vapours , and mixing the said vapours together , and by a new coagulation of them again . for every living body is a very alembick , full of perpetuall heat and vapours . for life is heat : and heat cannot but boile the matter that is put in , and by attenuation , turn it into vapours . xv now in every concoction , there is a separation of the profitable parts from the unprofitable : the first are digested and assimilated , the other are voided and streined forth . so in alembicks , the more subtle and profitable parts , ( that is the more fat and spirituous ) being resolved into vapour are gathered again into drops : and into a thick substance : but the more grosse and impure parts , called the dregs and excrements , sink down , and are afterwards cast out . xvi every concoction leaves behind it unprofitable dregs ; which are called excrements and drosse . thus we see it come to passe in the decoction of metals . now we must note that plants make little or no excrement : because they are nourished with a simple and uniform juice , which goes all of it into their nature : or if any thing remain , it sweats forth in gum . but living creatures ; because they consist of very dissimular parts , have need of a compound nutriment , that is solid and soft , dry and moist , hot and cold , &c. that so the more solid parts may have nutriment also whence by assimulation evey part draws that which will profit its selfe , the rest must of necessity be streined out . another reason is because plants are susteined with a little spirit , and that which doth not evaporate : but living creatures are full of spirit , ( for otherwise so grosse a frame could not be susteined and weilded ) and that is continually attenuated and spent . therefore they have need of more spirit then matter for their nutriment : and when that is extracted out of the spirituous parts , they void forth the rest . xvii the principall concoction in a living creature is threefold , chylification , sanguification , and membrification . the first is made in the stomack : the second in the liver : and the last in all the members . xviii every one of these concoctions hath three sorts of vessels . of ingestion . of digestion . of egestion . xix the vessels of chylification ; were the mouth , and the throat . the stomack or ventricle . the guts and the arse-hole . for the food being received at the mouth , is chewed with the teeth , or jawes , and passed through the throat . it is boiled in the stomack as it were in a close alembick for some houres . and from thence by evaporation it passeth into the entrals ( for the mouth of the ventricle towards the throat is shut up ) and becometh chylus , that is , a certain ferment like pap , or white broth . for it takes a white colour from the stomack by assimilation . the more subtle parts of this chyle are attracted to the liver , as a matter fit for bloud : but the excrements of this first concoction , are thick dregs , which are driven out by the guts and the back part , not by the simple motion of cession , but by the motion of antipathy , for the naturall spirits placed in the fibres of the guts , sucking forth that which is profitable , but turning themselves away from that which is unprofitable , and hatefull to them , contract the nerves of the guts , and thrust forward those burdens towards the passage . xx the vessels of sanguification , are the mesenterie . the liver . the vreteres , the spleen , and the gall . for the mesenterie encompassing the entrals vvith its strings ( which they call the mesaraicall veins ) sucks the best part of the chylus out of the entrals ; and carries them to the liver by the vena porta . now the liver concocts and separates that liquour again , for it assimilates the sweeter parts in colour to it selfe , and turns them to bloud , swelling with naturall spirit : with which neverthelesse there is flegme and yellow choler , and black mixt . the excrement of this second concoction is urine : namely , a wheaie and salt humour which floweth from the liver by the ureteres to the bladder ; whence by the channell of the genitall member it is sent forth . but because the d. concoction ought to be far more subtile then the first , it is not sufficient that the bloud is purged from its serosity . but both kinds of choler and flegme must of necessity also be purged from redundancy : the spleen therefore by sympathie attracts to it selfe vvhatsoever it perceiveth , that is too grosse and earthy in the bloud , and by little veins sends it again into the entrals , and by that means disburdens it selfe of that dreggy humour ; and last of all the gall attracteth those parts of the bloud that are too sharp and fiery , ( vvhose little bag hangs at the liver ) and by strings sends them again mixt into the entrals ; whence the bitternesse and ill sent of dung . xxi the vessels of membrification , are veins . every particular member . pores . for the veins proceeding from the liver spread themselves over all the parts of the body like boughs , and sending forth little branches , every way end in strings that are most tenacious ; from which every member apart sucketh , and by a slow agglutination assimilates it to it selfe , so that the bloud flowing into the flesh , becomes flesh , that in the bones turns into bone ; in a gristle , to a gristle ; in the brain , to brains ; just after the same manner as the juice of a tree is changed into wood , bark , pith , leaves , fruits , by meer assimilation . the excrements of this third most subtle concoction are subtle also , namely sweat and vapour , which alwayes breaths out through the pores . if any more grosse humour remains ( especially after the first and second concoction not well made ) it breeds scabs ; or ulcers , or the dropsie . xxii for the furthering of nourishment there is a spur added , that is appetite , or hunger , and thirst : which are nothing but a vellication of the fibres of the stomack , arising from the sharp sucking of the chylus . for the members being destitute of the juice , wherewith they are watered , solicite the veins of bloud : and the veins ( by the motion of continuity ) sollicite the liver ; the liver , the mesenterie ; that the entrals ; the entrals the stomack : which , if it have nothing to afford , contracts and wrinkles it selfe : and the strings of it are sucked dry , from whence proceeds first a certain titillation , ( and that we call appetite simply ) and afterward pain ( and this we call hunger ) and if solid meat be taken , but dry , because coction , or vaporation , cannot be made by reason of drinesse , there is a desire that moisture should be poured on , and this vve call thirst . it appears then why motion provokes appetite ? and why the idle have but little appetite , &c. xxiii the whole body is nourished at once together , by the motion of libration . to vvit , after the same manner , as the root in a plant doth equally nourish both it selfe , and the stock , and all the boughes . therefore no member nourisheth it selfe alone , but others vvith it selfe , and so all preserved . otherwise , if any member rob the rest of their nourishment ; or again refuseth it , there follows a distemperature of the vvhole body , and by and by corruption , at length death . xxiv a living creature being 〈◊〉 nourished , is not onely vegetuted , but also ( as long as his members are soft and extensive , ) augmented , the superficies of the members , yielding by little and little , and extending it selfe ; but as soon as the members are hardened ( after youth ; ) the living creature ceaseth to grow : yet goes forward in solidity and strength , so long as the three concoctions are rightly made . but when the vessels of the concoctions begin to dry up also ; the living creatures begins to wither away , and life grows feeble , till it fail , and be extinguished of the vitall faculty . xxv life in a living creature , is such a mixture of the spirits with the bloud and members , that they are all warme , have sense , and move themselves . therefore the life of living creatures consists in heat , sense , and motion ; and it is plain : for if any creature hath neither motion , nor sense , nor heat , it lives not . xxvi therefore every living creature is full of heat , sometimes stronger , and sometimes weaker . for every living creature is nourished how it appears out of that which went before , the nourishment is not made but by concoction : but reason teacheth that concoction is not made but by heat and fire . it comes therefore to be explained , whence a living creature hath heat and fire ? and by what means it is kindled , kept alive , and extinguished ? which the two following aphorismes shall teach . xxvii the heart is the forge of heat in a living creature , burning with a perpetuall fire , and begetting a little flame called the spirit of life which it communicates also to the whole body . ; hence the heart is said commonly , to be the first that lives , the last that dies . xxviii the vitall spirit in the heart , hath for its matter bloud ; for bellowes , the lungs : for channels , by which it communicates it selfe to the whole body , the arteries . our hearth fire hath need of three things , matter or fuell , and that fat . of blowing or fanning , whereby the force of it is stirred up . free transpiration whereby it may diffuse it selfe ; the same three the maker of all things , hath ordeined to be in every living creature . for the heart seated a little above the liver , drinketh in a most pure portion of bloud , by a branch of the veins : which being that it is spirituous and oily , conceives a most soft flame ; and left this should be extinguished , there lies near to the heart the lungs , which like bellowes dilating and contracting it selfe , blowes upon and fans that fire of the heart perpetually , to prevent suffocation : now being that that inflammation of the heart , is not without fume or vapour ( though very thin the said lungs by the same continuall inspiration exhaleth those vapours through the throat ; and drawing in cooler air instead thereof , doth so temperate the flame of the heat , whence the necessity of breathing appears , and why a living creature is presently suffocated if respiration be denied it . and that flame , or attenuated , and most hot bloud , is called the spirit of life ; which diffusing it self through the arteries , ( that accompany the veins every way ) cherisheth the heat both of the bloud ( that is in the veins ) and all the members throughout the whole body . now because it were dangerous to have this vitall spirit destroyed , the arteries are hid below the veins , only in two or three places , they stand forth a little : that , so the beating of that spirit , ( as well as of the heart it selfe , when the hand is laid upon the breast ) may be noted , and thence the state of the heart may be known . of the sensitive faculty . xxix sense in a living creature is the perception of those things that are done within and without the living creature , xxx that perception is done by virtue of a living spirit ; which , being that it is most subtle in a living creature , is called the animall spirit . xxxi that perceptive virtue consists in the tendernesse of the animall spirit : for because it is presently affected , with whatsoever thing it be wherewith it is touched . for all sensation is by passion ; as shall appear hereafter . xxxii the seat and shop of the animall spirits is the brain . for in the brain , there is not only greatest store of that spirit residing , but also the whole animall spirit is there progenerated . xxxiii the animall spirits are begotten in the brain , that is in bloud and vitall spirit . purified with the fanning of respiration . communicated to the whole body by nerves . the excrements of the brain are cast forth by the nostrils eares , and eyes ( that is by flegme and ●ears . ) for the strings of the veins and arteries , running forth into the brains , instill bloud and vitall spirit into them . and the bloud , that turns into the substance of the brains by assimilation : but the vitall spirit , being condensed by the coldnesse of the brain , is turned into the animall spirit : which the air , drawn in by inspiration , and getting into the brain through the hollownesse of the nostrils , and of the palate , doth so purifie with fanning every moment , that though it be something cold , yet it is most moveable , and runs through the nerves with inexplicable celerity . now the nerves are , branches or channels , descending from the brain through the body . for the marrow of the back bone , is extended from the brain all along the back of every living creature : and from thence divers little branches run forth , conveying the animall spirit , the architect of sense and motion , to all the members in the whole body . xxxiv to know the nature of the senses three things are pertinent , the things requisite . the manner . the effect . xxxv the things requisite are an object . an organ . a medium to conjoyn them . or sensile , sensorium , and the copula . xxxvi objects are sensible qualities inhering in bodies ; colour , sound , savour , tangor . for nothing is seen , touched , &c. of it selfe , but by accidents wherewith it is clothed . and if we would be accurate philosophers , n. w. of the three principles of things , only light or fire is preceptible . for matter and spirit are of themselves insensible : the light then tempered with darknesse , makes the matter visible . motion , ( which is from light ) makes a sound ; but heat ( which is from motion ) stirs up and temperates the rest of the qualities , odours , savours , tangors . xxxvii the organs of the senses are parts of the body in which the animall spirit receives the objects that present themselves ; namely , the eye , the eare , the nostrils , the tongue , and all that is nervie . nothing in all nature acts without organs : therefore the animall spirit cannot do it neither . xxxviii the medium of conjoyning them , is that which brings the object into the organ : in sight , the light ; in hearing , the air moved with breaking : in smels , the air vapouring : in taste , the water melting : in touch , the quality it selfe inhering in the matter . xxxix the manner of sensation is the contact of the organ with the object , passion , and action . there is but one sense to speak generally , and that 's the touch. for nothing can be perceived , but what toucheth us either at hand , or at a distance . there is no sense at all of things absent . xl therefore in every sensation the animall spirit suffers by the thing sensible . that there is no sensation but by passion is too evident . for we do not perceive heat or cold , unlesse we be hot or cold ; nor sweet and bitter , unlesse we become sweet or bitter ; nor colour , unlesse we be coloured therewith . our spirit , i say , residing in the organs , is touched and affected . therefore those things which are like us , are not perceived : as heat like our heat , doth not affect us . but we must observe that the organs , that they may perceive any qualities of the objects , want qualities of themselves ; as the apple of the eye , colour ; the tongue , savour ; &c. xli yet in every sensation the animall spirit doth reach upon the thing sensible : namely , in receiving , speculating , & laying up its species . for the animall spirit resident in the brain , what ever sensorie it perceives to be affected , conveys it selfe thither in a moment to know what it is : and having perceived it , returns forth with , and carries back the image of that thing with it ; to the center of its work-house , and there contemplates it , what it is , and of what sort : and afterward layes it up for future uses , hence the ancients made three inward senses . the common sense , or attention . the phantasie , or imagination . the memory , or recordation . but these are not really distinct : but onely three distinct internall operations of the same spirit . now that those inward senses are in brutes , it appears , because if they do not give heed , many things may and do usually slip by their ears , eyes , and nostrils . because they are endued with the faculty of imagining or judging . for doth not a dog barking at a stranger , distinguish betwixt those whom he knowes , and strangers ? yea sometimes a dog or a horse , &c. starts also out of his sleep : which cannot be but by reason of some dream . and what is a dream but an imagination ? because they remember also , for a dog that hath been once beaten with a cudgell , fears the like at the sight of every staffe , or gesture , &c. and therefore it is certain , that every living creature , even flies and worms , do imagine . but of the inward senses , more at large , and more distinctly in the chapter following . xlii the effect of sensation is pleasure , or grief . pleasure , if the sense be affected gently and easily with a thing agreeable thereto , with titillation ; griefe , if with a thing that is contrary to it , or suddenly with hurt to the organ . xliii and that the animall spirit alwayes occupied in the actions of sense , may somtimes rest , and be refresbed , sleep was given to a living creature ; which is a gathering together of the animall spirits to the center of the brain , and a stopping of the organs in the mean time , with the vapours ascending out of the ventricle . hence it appears . why sleep most usually comes upon a man after meat ? or else after wearinesse , when the members being chafed do exhale vapours ? why carefull thoughts disturb sleep ? that is , because that when the spirit is stirred to and fro , it cannot be gathered together , and sit still . what it is to watch , and how it is done ? namely , when the spirit being strengthened in it selfe , scatters the little cloud of vapours already attenuated , and betakes it selfe to its organs . why too much watching is hurtfull ? because the sprits are too much wearied , weakened , consumed , &c. thus much of the senses in general , somthing is to be said also of every one in particular . xliv the touch hath for its instrument the nervous skin : as also all the nervous , and membr anaceous parts of the body . therefore haires , nailes , bones , do not feel , &c. though you cut or burn them : because they have no nerves running through them . yet they feel in that part , where they adjoyn to the flesh , because they have a nervie substance for their gluten . hence the pain under the nailes , and membranes of the bones , is most acute . now being that the skin of the body is most glutinous , and altogether nervie , lest it should put the living creature to continuall pain and trouble , by being too sensitive , it is encompassed with a thin skin , called in latine , cuticula ( which we see come of somtimes in members that are scorched and bruised ) and void of sense , to restraine the violence of the sense . xlv the taste hath the tongue for its organ , a porous member , and alwayes moist , that so dry things also that touch it , may m●lt and give forth a savour , which penetrating the tongue by the nerves placed at the roots thereof , is by and by communicated to the brain . when the tongue is dry ( as in great thirst ) the taste perceives nothing ; and therefore god hath in his wise counsell provided , that in every perfect living creature , the vapours exhaling out of the ventricle , should be gathered together into spittle within the concavity of the mouth , and should water the tongue perpetually : for which purpose the porositie of the tongue serves very wel . yet there were added over and above two little kernels , called tonsillae , spongious too , alwayes preserving spittle for the use of the tongue . xlvi the nostrils are the organs of smelling , and that cribrous bone placed over them ; by which as through a sponge , the smel comming from things may enter the brain . therefore when the catarrhe flowes and fils the nostrils , smelling is hindred . this is the most open way to the brain , and therefore most powerfull to affect the animall spirit , either immediately pleasing , or recreating or strengthning it , or molesting and suffocating it . for hence it is , that grosse , fuliginous , impure vapours kill : but sharp smells raise a man , even out of a deep swoone . xlvii . hearing hath the ear for its organ ; which containes the hole to the brain , together with a gristly border winding about like the shell of a snaile , adjoyned without to receive the motion of the aire when in is stricken , and turne it inward : but within at the center of the windings is a little drum , with a little bit of flesh standing by it , like a hammer ; which being beaten with the aire that enters , beats the drum also , which the spirit perceiving , judges of the greatnesse or smalnesse , nearnesse or distance of the thing beaten with the aire : and by multiplied experience , knows what it is that moves the aire , and of what sort . this wonderful organ is easily corrupted within and without . within , if the passages be stopped with flegme : & much more if the hammer or the drum be hurt with rottennesse . but without , if the ear , ( that is that gristly border ) be cut off : for then the sound slips by the ear , or being received in ordinately , makes only an inordinate noise . to help which the creator gave living creatures two ears apiece . now it appeares hence , why too sharpe or too dull sounds offend , the temperate please us ? because they agree better with our spirit . . why a sound penetrates obliquely also ? because the aire moved , moves that which is next it round about by the motion of diffusion . . why a sound spread round about , failes by little and little ? because it is just as when the water of a poole is moved with a stone falling into it . excepting that the water quivers a good while in that whole circle : but the circle of the rain moved , passeth away together and at once : for the sound of a bell , doth not sticke in the aire , but is wheeled about in the sounding bell . . why when one hears all hear the same ? because a sound is a real commotion of the aire , which arrives at the ears of all those that are within that circle . . what the echo is ? namely a sound reflected from hollow places : after the same manner as the circulations of the water made in a vessel , after they have been at the sides , returne again toward the center . xlviii . the sight hath the eye for its organ ; which is nothing else but a living looking glasse , receiving into it self the images of such things as present themselves , and transmitting them to the brain to be judged of . the fabrick of the eyes is admirable . for beneath the fore-head of every living creature , god hath hollowed out in the skull two windows , into which the outmost membrane of the brain , sends two things like bags , filled with the humorus that come from the braine . in the midst of which there is a pipe woven together of an opacous thin membrane , yet full of a most pure chrystalline humour : they call it the apple of the eye , in which vision is properly made , this is encompassed with a net-work , full of a watery or glassie humour : and last of all , that membrane which the common sort call the white of the eye ; but philosophers ( because it is hard and polished over like a horne ) call cornea , and this is transparent over against the apple and the net-work , elsewhere it retaines its whitnesse . now under the root of the apple lies the optick nerve , by which the image of the thing perceived , passeth straight to the center of the braine , xlix . no vision is without the ministery of light ; for that reflecting from things and coloured with their aspect diffuseth it self every way , and wheresoever it falls upon a glasse , it impresseth the image of the said things . whence it appeares : . why only things that are coloured are seen ? because the light must of necessity rebound to the eye , but that which hath no colour is transparent as the aire , &c. . why those things that are to be seen must of necessity be enlightned ? because sight is the resiliencie of the light from the object to the eye . . why the eye placed in the shade or in the dark sees the stronger ? because it receives the light reflected without any impediment . for if the eye it self be enlightned also the light reflected from it , meets with the other light ( coming from things ) and so there is a collision and a dissipation of them both . . vvhy we see nothing , if there be any thing betwixt the eye and the object ? because the reflexion of the light is not made but in a right line . . vvhy some living creatures see best in a strong light , others in an obsure light ? because the lucidity of the animal spirit is diverslly proportionated . so spiders and flies see the smallest things , which passe our sight , ; ( and much more the sight of an horse or an elephant , &c. ) because there are more subtile spirits in a more subtile body . . vvhy whitenesse disgregates the sight , and if it be overmuch , dissipates and corrupts it ? because it is the very light it self reflecting , whose nature is to penetrate , attenuate , part asunder and diffuse the object . for to that end it was sent into the world . l. viston is three-fold , streight , reflected , and refracted right or direct vision is that whereby the light is seen , suppose the sun or fire : for here the light offers it self to the eye by a single line . reflected is , that whereby other things are seen in a free aire : for there the light reflected from things , comes to the eye by a second line ( for by the first line the light falls upon the object , by the second from thence upon the eye . ) refracted is that whereby things are seen through a double medium , and so by refracted lines : as when an oare or pole seems broken in the water . also when a piece of mony in the bottome of a vessel full of water , seemes bigger and nearer the superficies , so that one may go back and see it . of the motive faculty . li. motion was given to a living creature . . to seek his food . . for those actions to which every one is destinated . . to preserve the vigour of life . for a living creature being of a more tender constitution then a plant , would more easily putrifie and perish , if it were not quickned by most frequent motion . therefore the creator hath most wisely provided for our good , that we cannot so much as take our meat without labour and motion . lii . the moving principle is the animall spirit . therefore a body without life , though never so well furnished with organs , moves not : and when the braine , the feat of the animall spirits is ill affected ( for example either with giddinesse or a surfet ) the members presently fall , or at least stumble and totter . and when the nerve of any member is stopped , it is presently deprived both of motion and sense ; as may be seen in the palsie and apoplexie . liii . now the animall spirit moves either it self only , or the vitall spirit with it : or lastly the members of the body also . liv. the animall spirit moves it self perpetually , sometimes more , sometime lesse : namely , running out and into the organs of the senses : or howsoever stirriug it self in its work-house . for from this inward motion of it , are perpetual phantasies or imaginations even in sleep ; which then we call dreams . lv. it carries the vitall spirit along with it , when at the sense of something , either pleasing or displeasing it conveyes it self to and fro through the body , taking that with it as it were to aide it ; as it is in joy and sorrow ; hope and feare ; gratulation and repentance ; and last of all in anger . for joy is a motion , wherein the spirit poureth forth it self at the sense of a pleasant object , as though it would couple it self with the thing that it desireth . thence that lively colour in the face of a joyful man from the vital spirit , flowing thither with a most pure portion of the blood . and this is the cause why moderate joy purifies the blood , and is helpful to prolong life . see prov. . v. . & . v. . sorrow is a motion , whereby the vitall spirit at the sense of an object that displeaseth it , runnes to its centre ; the heart as it were feeling a hurtful thing , thence palenesse in the face of those that are affrighted , and stiffnesse of the skin and haires ; hence also danger of death , if any one be often and greatly affected with sorrow : the like motions are in hope and fear , joy and sorrow ; that is , in the sense of good or bad , either present or past . but anger , is a mixt motion , whereby the spirit for fear of injury flies to the center , and thence poures forth it self again as it were in revenge . hence they that are angry , are first pale , and afterwards red , &c. n. w. all these motions commonly called affections , or passions of the minde , are common to all living creatures : but according to more and lesse , for sanguine creatures are merry ; melancholy , sad ; flegmatick , faint ; cholerick , furious , &c. lvi . the said animall spirit moves the members , but with the use of instruments ; tendons and muscles , and the joynts of the bones . the puppets wherewith juglers ( a pleasant sight to children ) shew playes , that they may turne themselves about , as though they were alive , must of necessity have : joynts of the members , that they may bow . nerves or strings with which drawne to and fro they are bowed . some living strength which may draw the nerves forward and backward ; which the neurospasta that is hid under the covering supplies . just so to the motion of a living creature , there are requisite : joynts or knuckles of bones . for bones were given to a living creature , that he might stand upright : but that he might bend also , his bones were not given him continued , but divided with joynts of limbs . . certain ligaments fastned about the bones , wherewith attraction and relaxation might be made ; therefore certaine tendons were given them as it were cords , being of a nervy and half gristly substance , which growing out of the head of one bone , and running along the side of another bone , grow to the lower head thereof ; and when the tendon is drawne , the following bone is drawne , so as to bend it self . now it is to be noted , that these tendons about the joynts of the bones are bare on both sides ; but about the middle of them they are extended into a kinde of a membranceous purse stuffed up with flesh : which flesh or fleshy purse they call a muscle , of which every member hath many : not only least that the tendons when they are drawne should depart out of their place ; or the bones or tendons be hurt with oft rubbing against one another ; or for the shape of a living creature only ( for what a body would that be which consisted of meer bones , veins , nerves , and tendons ? a sceleton ) but because there can be no motion at all without muscles : as it shall forthwith appear . . the neurospasta or invisible mover , is the animal sqirit ; which as it can at the pleasure of the phantasie , convey it self into the belly of this or that muscle , so it stretches or dilates it as it vvere a paire of bellowes , and drawes in that vvhich is opposite , from whence nothing can follow but the bending of that member . thence it appears : . that the animall spirit can move nothing without an organ : for why doth no man bend his knees before ? because there wants a knuckle above . why doth no man move his ear ? because that member wants muscles , &c. . it appeares also , that by how many the more muscles are given to any member , by so much the nimbler it is unto motion : by how much the bigger , so much the stronger ; for example , in the hands and feet , that they might be sufficiently able to undergo the variety of labours and going . it appeares also why they that are musculy or brawnie , are strong , but those that are thin , are weak ? . it appeares also that the animal spirit is most busie in motion , running to and fro at the command of the phantasie , most speedily through the nerves and arteries . . that the motion of a living creature is compounded of an agitative , expansive and contractive , impulsive and continuative motion . for the animal spirit coveys it self at the pleasure of the phantasie , into this or that muscle : and the muscle giving place to the spirit flowing in , stretcheth forth it self : then when the muscle is stretched forth in breadth , the length of it must be contracted of necessity : and the tendon followes the muscle contracting it self , and drawes with it the head of the next bone by the motion of continuity ; all with inexplicable quicknesse . . it appears also that this local motion ( either of the whole living creature , or of some member ) is made about something immoveable with various enforcings . . and because it is with enforcing , it cannot be without wearinesse . . and because it is vvith vvearinesse , there is sometimes needs of rest ; vvhich is given in three kinds . standing . sitting . . lying . standing is a resting of the feet , but with an inclination of the body to motion : therefore it is done by libration . sitting is rest in the middest of the body : whereby the other parts are the more easily preserved in aequilibrio . lying is a total rest . that is , a prostrating of the body all along : but as too much motion brings wearinesse , so too much rest causeth tediousnesse : because the spirit loves to stir it self . and the same position of the members a long while together by rest , is alike troublesome : both for that the lower members are pressed with the vveight of the upper , and also for that the spirit desires to move it self any way . hence it is in that vve turne us oft in our sleep . of the enuntiative faculty . that a living creature might give knowledge of it self by a voice , the animal spirit doth that , at the direction of the phantasie : but it hath these organs , the lungs , the rough arterie , and the mouth . lvii . to every living creature ( fishes excepted ) there was given lungs , to coole the heart , with a gristly pipe called the rough arteterie . which notwithstanding serves withall to send forth a voice : because that in the upper part of it , it hath the forme of a pipe , wherewith the aire being stricken may be divided and sent sounding forth . lviii . and that the voice might be both raised , and let fall , that pipe is composed of gristly rings ; the lowest of which , if it oppose it self to the aire as it passeth by , there is a deep repercussion , that is a grave voice ; but if the highest , there is an high repercussion , that is a shrill voice , every one may make triall of that in himself . lix . and that the sound may be articulate , ( as in speech and the singing of some birds ) that the tongue , beating the sound too and fro , also the lips , the teeth and nostrils , and the throat performe . of the defensive faculty . lx. the animall spirit if it perceive any hostile thing approach unto it , hath presently recourse to its weapons , whereby either to defend it self ( setting up its haires , bristles , scales , prickles ) or to offend and hurt its enemies ( using its hornes , nailes , wings , beak , hands , &c. ) which by vertue of what strength it is done , may already be known out of what hath been said before . of the generative faculty . seeing that living creatures as well as plants , are mortal entities : they must of necessitie be multiplied , for the conservation of their species ; touching which marke the axiomes following . lxi . because that the generation of living creatures , by reason of the multitude and tendernesse of their members , could not commodiously be performed in the bowels of the earth : they had a different sex given them . and it was ordained that the new living creature should be formed in the very body of the living creature it self . as the sun by its heat doth beget plants in the wombe of the earth , so it may also those living things , whose formation is finished with in some few dayes , as wormes , mice , and diverse insects , ( which is done either by the seed of the same living creatures falling into an apt matter scattered , or by the spirit of the universe , falling into an apt matter . but more perfect living creatures , which consist of many and solide members , and want much time for their formation ( as a man , an horse , an elephant ) it cannot beget . for being that the sun cannot stay so long in the same coast of heaven , the young one would be spoiled before it could come to perfection . i herefore the most wise creatour of things , appointed the place of formation to be , not in the earth , but in the living creature it self ; having formed two sexes , that one might do the part of the plant bearing the seed , the other of the earth , cherishing , and as it were hatching the seed . this alone and none other is the end of different sexes in all living creatures . wo be to the rashnesse and madness of men , which abuse them ! as no beast doth . the members , whereby the sexes differ , are the same in number , site and form , and differ in nothing almost unless it be in regard of exterius and interius : to wit the greater force of heat in the male thrusting the genitals outward , but in the female by reason of the weaker heat the said members conteining themselves within : which anatomists know . lxii the spirit is the directour of all generation , like as in plants ; which being heated in the seed , first formes it selfe a place of abode , that is the brains and head : and thence making excursions , formes the rest of the members by little and little , and gently : and again retiring to its seat , rests and operates by turns : whence the original of waking and fleeping . therefore the formation of a living creature doth not begin from the heart , as aristotle thought , but from the head , for the head is as it were the whole living creature ; the rest of the body is nothing but a structure of organs for divers operations . and that appears plain , for some living creatures ( as fishes ) have no heart , but none are without a head and brains . of the kinds of living creatures . thus much of a living creature in generall ; the kinds follow . lxiii a living creature according to the difference of its motion is reptile . gressile . natatile . volatile . lxiv reptile , or a creeping thing is a living creature with a long body , wanting feet , yet compunded of joynts ( or gristly rings ) by the contraction and extension of which it windes up and reacheth out it selfe : as are wormes and serpents . lxv gressile is , that which hath feet ( two or more ) and goeth ; as a lizard , a mouse , a dog , &c. lxvi natatile is , that which passeth through the water by the help of finnes : it is called a fish : amongst which crabs also , and divers sea-monsters are reckoned . lxvii volatile is , that which moves it selfe through the air , by the shaking of its wings ; and is called a bird . the lightnesse of birds to flie , is from their plumosity . for every plume or feather , not only in the stalk , but through all its parts , and particles of its parts , is hollow and full of spirit and vapour . and for this cause no birds pisse : because all their moisture perpetually evaporates into feathers . it is impossible therefore for a man to flie , though he fit himselfe with wings , because he wants feathers to raise him : and those which he takes to him , are dead , and void of heat and spirit . lxviii small living things are by a speciall name called insects ; as flies , wormes , &c. they are called insects , from the incisions whereby their bodies are cut off round as it were . these may be divided after the same manner . for wormes are reptile , lice , fleas , punies , spiders , &c. gressile , the water-spider , and the horse-leech , &c. natatile , flies and gnats , &c. volatile , and all those with infinite differences , so that here also there is not wanting a most clear glasse of the admirable wisdome of the creatour ; and a schoole to man , to learn virtues , and forget vices ( of both which there are an expresse image in living creatures , which the scripture oft inculcates . ) an apendix . of the tenacious inherencie of the animall spirits in its matter . we shewed toward the end of the ninth chap , how fast the naturall and vitall spirit inhereth in its matter : we are now to give notice of the like in the animall spirit , how firmly it also abideth in its matter , that is the bloud , the understanding of which thing , will also adde much light to those places of scripture , where it is said that the soule of every living creature is in the bloud thereof ; yea , that the bloud of all flesh , is the life thereof , as gen. . v. . levit. . v. . and . deut. . v. . ) and to certain secrets of nature , which they are astonished at , who are ignorant of the manner and reason of them . i first , then it is certain that the animall , as well as the vitall spirit , may be bound into its seed with the cold , so as that for a time it cannot exercise its operation . for as grains of corn kept all winter ( either in a garner , or in the earth ) do bud neverthelesse : so the eggs of fishes , frogs , pismires , beetles , scattered either upon the earth or waters , do bring forth young the year following . ii in bodies already formed the same spirit , compelled sometimes by some force , forsakes the members , and ceaseth from all operation : yet conglobates it selfe to the center of the body , and coucheth so close , that for many dayes , moneths , years , it lies as it were asleep , yet at length it awakens again , and diffuseth it self through the members , and proceeds to execute vitall operations as it did before . we find it so to be in flies , spiders , frogs , swallowes , &c. which in winter lie as though they were dead in the chinks of wals , or chaps of the earth , or under the water , yet when the spring comes in , they are alive again so flies choaked in water , come to life again in warm cinders : like as it is certain , that men strangled have been brought to life again after some hours , and besides there is an example commonly known of a boy killed with cold , and found four dayes after , and raised again with foments . trances continued for some dayes are ordinarily known hence : some ready to be buried , as though they had been dead indeed , yea , and buried too , yet have lived again ▪ some geographers have written , how that in the farthest parts of moscovia , men are frozen every year with extream cold , and yet live again like swallows : which notwithstanding as a thing uncertain , we leave to its place . iii the third and the most strange is this , that the spirit flowes out with the bloud that is shed , and yet gives not over to maintain its consent with the spirit remaining within the body : ( whither the greater part thereof remain or only the relicks : ) which is most evidently gathered from divers sympathies and antipathies , i will illustrate it with five examples . whence is it ; i pray you that an oxe quakes , and is madded , and runs away at the presence of the butcher ? is it not because he smels the garments , the hand , the very breath of the butcher stained with the bloud and spirit of cattle of his own kind ? which is also most clear from the irreconcilable antipathy , which is found to be betwixt dogs , and dog-killers . whence is it that the body of a slain man bleeds at the presence of the murderer , and that after some dayes , or months , yea , and years ? ( for it is manifest by a thousand trialls that it is so : and at itzenhow in denmark , simeon gulartius relates that the hand of a dead man cut off , and hung up , and dried in prison , discovered the murderer full ten years after by bleeding , as a thing confirmed by great witnesses , and those of the kings counsell ) and certainly we are not to flie to miracles where nature it selfe by constant observation shewes her lawes . it is very likely that the spirit of the man ready to be slain , provoked with the injury when it is shed forth with the bloud , pouring out it selfe as it were in revenge , leaps upon the murderer : and that after the same sort as we see a dog , a wild beast , or oxe , when he is killed , run furiously upon him that striketh him . for if the spirit do so yet abiding in the body , why not parted from it ? therefore it is to be supposed that it leaps upon the murderer , and seises on him . whence it comes to passe , that when he comes near the body ( especially if he be commanded to touch it , or look upon it ) look how much spirit is left in the body , it hasteth to meet with its spirit , with its chariot the bloud , namely by sympathie . hence that antipathie which more subtle natures find in themselves against murderers though unknown . for they tremble at the very presence of murderers , and nauseat if they do but eat or drink with them , &c. . the cunning of a most excellent chirurgeon in italy is [ well ] known , who helpt one that had lost his nose , carving him another out of his arme , cut and bound to his face for the space of a moneth : and the ridiculous chance [ that happened thereupon ] a little after is also known . a certain noble man having also had his nose cut off in a duell , desired his help ; but being delicate and not willing to have his arme cut , hired a poor countrey fellow , who suffered himselfe to be bound to him , and his arme to be made use of to repair his nose . the cure succeeded : but when as about some six years after , ( or thereabouts ) the country man died , the noble mans nose rotted too , and fell off . what could be the cause of it , i pray you , but that the spirit , and that locally separated , doth maintain its spirituall unity ? therefore when the spirit went out of the countrey mans carcasse , as it rotted , part of it also went out that the noble mans nose , and his nose ( by reason of the noble mans spirit , succeeded not [ into the place of it ] as being into the lump of anothers [ flesh ] ) rotted also , and fell off . it is accounted amongst the secrets of nature , that if friends about to part , drink part one of anothers bloud , ( and so addes a part of his spirit to his own ) it will come to passe , that when one is sick , or ill at ease , though very far asunder , the other also will find himselfe sad : which if it be true , ( as it is most likely ) the reason is easie to be known . the magneticall medicine is very famous amongst authours : with which they do not cure the wound it selfe , but the instrument wherewith he wound was given , or the garment , wood , or earth besprinkled with the bloud of the wound , is onely anointed : and the wound closes and heals kindly . some deny that this is done naturally , who do not sufficiently consider the secret strength of nature . yet examples shew that this kind of cure , with an ointment made with most naturall things , ( yea with nothing but the grease of the axeltree , scraped off from a cart ) hath certain successe , without using any superstition . wherefore it is credible , that the spirit poured out of the body with the bloud that is shed , adheres partly in the bloud , partly to the instrument it self : ( for it cannot abide without matter ) & being forced thence with the fat that is applied returnes to its whole , and supplies that , and hereto perhaps that observation appertains concerning the venom of a snake , viper , or scorpion conveyed into a man with a bite . for if the same beast , or but the bloud or fat thereof , be forthwith applied to the wound , it sucks out the venom again , because it returns to its own connaturall . more of this kind might be observed by approved experiments . last of all , it is not unworthy of our observation , that the animall spirit doth form living creatures of another kind , rather then quite forsake the putrifying matter : namely , wormes , and such like . now it is certain by experience , that of living creatures that are dead , and putrified those living creatures are especially bred on which they were wont to feed when they were alive . for example , of the flesh of storks , serpents are bred , of hens spiders , of ducks frogs , &c. which that it will so come to passe , if they be buried in dung , john poppus a distiller of coburg , hath taught after others . it appears then that the animall spirit is every where , and that very diligently busied , about the animating of bodies . chap. xi . of man. i a man is a living creature , endued with an immortall soule . for the creatour inspired a soul into him , out of himselfe , gen. ● . v. . which soul is called also the mind and reason , in vvhich the image of god shineth . ii therefore he is compounded of three things , a body , a spirit , and a soule . so the apostle testifies . thes. . . let your whole spirit , and soul , and body be kept blamelesse . and so cor : . vers . . he distinguisheth betwixt the spirit and the minde . and indeed so it is : vve have a body compounded of the elements as vvell as bruits ; vve have a spirit from the spirit of the world , as vvell as they : but the soule or minde is from god. the first vve bear about us mortall : the second dissipable : but the last enduring ever without the body ; as we are assured by faith . therefore when thou seest a man , think that thou seest a king , royally cloathed , and sitting in his royall throne . for the minde is a king , his robe is the spirit , his throne the body . iii the body is the organ and habitation of the spirit : but the spirit is the habitation and mansion of the soul. for as the spirit dwels in the body , and guides it , as the pilot doth the ship ; so the soul dwels in the spirit , and rules it . and as body without a spirit , neither moves it ●f , nor hath any sense of any thing ( as it to be seen in a dead carcasse : ) so the spirit vvithout the minde , hath no reason , nor understands any thing ; as we see in bruit beasts . therefore the soul useth the spirit for its chariot and instrument ; the spirit , the body ; and the body , the foresaid instruments . iv as the spirit is affected by the body ; so is the minde by the spirit . for as vvhen the body is diseased , the spirit is presently sad , or hindred from its action : so vvhen the spirit is ill disposed , the minde cannot performe its functions dextrously : as vve may see in drunken , melancholie , mad-men , &c. hence it is , that the gifts of the minde follow the temperature of the body ; that one is more ingenious , courteous , chast , courageous , &c , then another . hence that fight within us , which the scripture so oft mentions , and we our selves feel . for the body and the soul , being that they are extreams ( the one earthly , the other heavenly ; the one bruit , the other rational ; the one mortall , the other immortall ; are alway contrary to one another in their inclinations . now the spirit which is placed betwixt them , ought indeed to obey the superiour part , and keep the lower part in order as its beck . yet neverthelesse it comes oft so to passe , that is carried away of the flesh , and becomes brutish . v. such a body was given to man as might fitly serve all the uses of his reasonable soule , and therefore : furnished with many organs . erect . naked and unarmed , that it might be free of it self , and yet might be cloathed and armed any way as occasion required . for the hand , the instrument of instruments , the most painful doer of all works , vvas given to man only . he only hath obteined an erect stature , least he should live unmindful of his countrey , heaven . again , he only was made naked and unarmed ; but both by the singular favours of god. for living creatures whilest they always bear about them their garment , ( haires , feathers , shels ) and their armes ( sharp prickles , horns ) what do they bear about them but burdens , and hindrances of divers actions ? the liberty granted to man , and industry in providing , fitting and laying up all things for his use and pleasure , is something more divine . vi. a more copious and pure spirit was given to man , and therefore his inward operations are more excellent , namely a quicker attention , a stronger imagination , a surer memory , more vehement affections . the first appears from the braine , which is given in greater plenty to man then to any living creature , ( considering the proportion of every ones body . ) for all that round head , and of so great capacity , is filled up vvith brain ; to what end ? but that the spirit might have a more spacious vvorkhouse and palace . the rest are known by experience as followeth . vii attention is a considerate receiving of the objects , brought into the sensorie instruments . we said in the former chapter , that it is commonly called the common sense . this vvas given to man so much the quicker , as it is destinated to more objects , and more distinctly to be perceived . viii imagination , is the moving of things perceived by the sense within , and an efformation of the like . for the image of the thing seen , heard , or touched with attention ; presently gets into the brain , which the spirit by contemplation judges of , what it is , and how it differs from this or that thing ? therefore it may well be called ( in this sense ) the judgment . this imagination is stronger in a man , then in any living creature : so that it feignes new formes of things , namely by dividing or variously compounding things conceived . and this is done with such quicknesse , that upon every occasion we imagine any thing to our selves , as vve find dreaming and waking : and by how much the purer spirit any one hath , he is so much the more prompt to think or imagine ; but dulnesse proceeds from a grosse spirit . observe this also : that the animal spirit vvhen it speculates forward , and drawes new images of things from the senses , is said to learne , vvhen backward , resuming images from the memory , it is said to remember : when it is moved too and fro vvithin it self it is said to feigne somewhat . note also , that from the evidence of sensation growes the degree of knowledge , for if the sense perceive any thing a farre off , or weakly and obscurely , it is a generall conception : if nearer , distinctly , and perspicuously , it is a particular conception : for example , when i see something move a great vvay off , i gather it to be a living creature : vvhen i come near , i know it to be a man , and at length this or that man , &c. ix . memory ( remembrance ) is the imagination of a thing past , arising from the sense of a thing present , by reason of some likenesse . for vve do not remember any thing otherwise , then by a like object : for example , if i see a man , that resembles my father in his face , presently the memory of my father comes into my minde . so by occasion of divers accidents , as place , time , figure , colour , found , &c. divers things may come to minde , where the like vvas seen , heard , &c. vvhich occasion sometimes is so slight and suddain , that it can scarce be marked , for what is quicker then the spirit ? n. now it may be demanded : seeing that the animal spirit moveth it self so variously in the brain , yea , and other nevv spirit alwayes succeeding by nutrition ; how is it that the images of things do not perish , but readily offer themselves to our remembrance ? answ : look down from a bridge into the vvater gently gliding , you shall see your face unvaried though the vvater passe away . and vvhen you see any thing tossed vvith the vvind in a free aire , the winde doth not carry away the image of the thing from thine eye : what is the cause ? but that the impression of the image is not in the water , nor in the aire : but in the eye , from the light reflected indeed from the water and penetrating the aire . so then in like manner , an inward impression is not really made in the brain , but by a certaine resplendency in the spirit : which resplendency may be kindled again by any like object . otherwise if images vvere really imprinted in the brain , we could not see any thing otherwise in our sleep , then it had once imprinted it self in the brain being seen . but being that they are variously changed , it appears that notions are made not by reall impressions , but by the bare motion of the spirit , and the imagination of like by like . x an affection is a motion of the minde , com●ng from imaginations desiring good , and shunning evill . there are more affections and more vehement in a man. for bruits scarce know shame , envy and jealousie , and are not so violently hurried into fury and despaire , or again into excessive joyfulnesse ; thence laughter and weeping still belong to man only . xi the minde of man is immediately from god. for the scripture saith , that it was inspired by god , gen. . v. . and that after the death of the body it returnes to god ; that gave it , eccles. . v. . for it returnes to be judged for those things which it did in the body , whether good or evill : c●r . . v. . but we are not to thinke that the soul is inspired out of the essence of god , as though it were any part of the deity : ( for god is not divisible into parts , neither can he enter into one essence with the creature . ) and moses vvords sound thus : and god breathed into the face of adam the breath of life , and man became a living soule . see he doth not say that that breath ( or inspiration ) became a living soule , but man became a living soul ) nor yet are we to think , that the soul was created out of nothing , as though it were a new entitie ; but only that a new perfection is put into the animall spirit in a man : so that it becomes one degree superiour , to the soul of a beast , that appears out of zach. ● . v. . where god testifies that he formes the spirit of man in the midst of him . behold , he forms , and not creates it ! it is the same vvord ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 jatzar ) vvhich is used of the body also ; gen. . v. . as therefore the body is formed of the prae-existent matter , so is the soul of the prae-existent spirit of the vvorld . aud by cousequent even as the earth , vvater , air , and skie , are all one matter of the world , differing only in the degree of their density : so the naturall , vitall , animall , and this mentall spirit , are all one spirit of the world , differing only in the degree of their purity and perfection . therefore it is credible , that the divine inspiration conferred no more upon man , but this , that he refined the inmost part of his spirit , that in subtility of actions he might come nearest to god of all visible creatures . fixed it , that it might subsist both in the body and out of the body . therefore the scripture makes no other difference betwixt the spirit of a man and of a beast , then that the one ascends upwards , the other goes downwards , ( that is the one flees out of the matter , the other slides back into the matter ) eccles. . v. . hence also that question , whether the soul be propagated by generation ? may be determined . the root of the soul which is the vitall and animall spirit , is certainly by generation : but the formation thereof ( that the inmost parts thereof should become the mentall spirit , or the minde ) god attributes to himself , zach. . . yet not concurring extraordinarily , or miraculously , but because he hath ordained that it shall be so in the nature of man. it appears also , why man is commonly said to consist of a body and a soule only ? namely , because , the rationall soule is of the spirit , and in the spirit . for as our body is made of a four-fold matter , that is , of the four elements : so our soule ( to speak generally , and contradistinguish it from the body ) consists of a fourfold spirit , naturall , vitall , animall , and mentall . xii there are three faculties of the mind of man , the understanding , the will , and the conscience . these answer to the three functions of the animall spirit , or to the inward senses ; out of which also they result . for we have said , that as the spirit useth the body for its organ , so the soule useth the spirit . therefore the three inward senses , attention , judgement , and memory , are instruments by which the soule useth the understanding , wil● , and conscience . for by diligent attention it begets understanding of things : by imagination or judging , choise , that is , to will or nill : by remembrance , conscience . xiii the understanding is a faculty of the reasonable soule , gathering things unknown out of things known , and out of things uncertain compared together , drawing things certain , by reasoning . xiv to reason is to enquire the reasons and causes why any thing is , or is not , by thinking thereon . for the mind or reason doth from the experiments of the senses gathered together , first form to it selfe certain generall notions : as , when it seeth that the fire scorcheth all things , it formes to it selfe this rule as it were : all fire burneth , &c. such kind of experimentall notions they call principles , from which the understanding , as occasion is offered , frames discourse . for example , if gold melt with fire , then it is hot also , and burns when it is melted . whence follows this conclusion : therefore if the workman pour gold into his hand , he is burnt therewith . see here is understanding , and that of a thing never seen ! to which a bruite cannot attain . for they do not reason but stay simply upon experiments . as if a dog be beaten with a staffe , he runs away afterward at the sight of a staffe , because his late suffering comes into his memory : but that he should reason , ( for example , a staffe is hard ; and pain was caused me with a staffe : therefore every hard thing struck against the body causeth pain : ) this he cannot do , therefore intelligere , to understand , is inter legere , that is , amongst many things to chuse and determine what is truly , and what is not . xv when ratiocination doth cohere with it selfe every way , it begets verity : if it gape any where , errour . xvi promptnesse of reasoning is called ingenuity ; solidity , judgement ; defect , dulnesse for he is ingenious , who perceives and discourseth readily : he judicious that with a certain naturall celerity giveth heed whether the reasoning cohere sufficiently every way . he is dull that hath neither of them . the two first are from the temperature of bloud and melancholy ; the last comes from abundance of flegme . for melancholy ( understand not grosse and full of dregs , but pure ) tempered with much bloud , giveth a nimble wit ; but moistned with lesse , a piercing and constant judgement : which is made plaine by this similitude . a glasse receiving and rendring shapes excellently , is compounded of three exceedings : exceeding hardnesse , exceeding smoothnesse , exceeding blacknesse : for the smoothnesse receives shapes : hardnesse reteins them : the blacknesse underneath clears them . ( hence the best sort of glasses are of steel , those of silver worse , and of glasse better : by reason of their greater smoothnesse and hardnesse under which some black thing is put , or cast , that it may adhere immediately : for instance , lead . if it could be iron or steel , it is certain , that the images would be the brighter for blackness . ) so the animall spirits , receiving agility from pure bloud , strength and constancy from melancholy , make men ingenious : and when the prevailing melancholy clarifies the imagination ; judicious , too much flegme overflowing both , makes men stupid . yellow choler conferreth nothing but mobility to the affections : whence it is not without cause , called the whetstone of wits . xvii the understanding begins with universals , but ends in singulars . we have observed the same touching the senses , upon the eighth aphorisme . for there is a like reason for both , in as much as the intellect considering any object , first knows that it is something ; and afterwards enquires by discoursing what it is , and how it differs from other things , and that alwayes more and more subtilely . for universals are confused , singulars distinct . therefore the understanding of god is most perfect , because he knowes all singularities , by most speciall differences : therefore he alone truly knoweth all things . but a man by how many the more particulars he knows , and sees how they depend upon their generals , by so much the wiser he is . therefore aristotle said not rightly , that sense is of singulars , but understanding of universals . xviii the will is a faculty of the reasonable soul , inclining it to good fore-known , and turning it away from evill fore-seen . for the soule works , that whereunto the will enclines ; and the will enclines , whither the understanding leads it . it follows this for its guides every where : and erres not unlesse it erre . as , when a christian chuseth drunkennesse rather then sobriety , ( though he be taught otherwise ) he doth it , because the intellect deceived by the sense , judgeth it better to please the palate , then to be tormented with thirst , ( though perverse . ) therefore we must have a speciall care , least the intellect should erre , or be carried away with the inferiour appetite . it appears also from thence , that if all men understood alike , they would also will and nill alike : but the diversity of wils , argues a diversity of understanding . xix if the will prudently follow things that are truly good , and prudently avoid things that are truly bad , it begets virtue ; if it do the contrary , vice . for virtue is nothing else , but a prudent , and constant , and ardent shunning of evill , and embracing of good : vice , on the contrary , is nothing but a neglecting of good , and embracing of evill . xx the conscience of man , is an intellectuall memory of those things which reason dictates either to be done , or avoided ; and what the will hath done or not done according to this rule ; and what god hath denounced to those that doe them , or doe them not . therefore the function of it in the soule is three-fold : to warn , testifie , and judge of all things that are done , or to be done see by the wisdome of god an inward . monitor , witnesse , and judge , and always standing by , given to man ! woe be to him that neglects this monitor , contemnes this witnesse , throwes off the reverence of this judge ! xxi it appears out of that which hath been said , that man is well termed 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , a little world . because he is compounded of the same that 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or the great world is : matter , spirit , light . he resembles the universe in the site of his members : for as that is divided into three parts , the elementary , the coelestiall , and the supercoelestiall : so a man hath three ventres or bellies ; the lowest which serves for nutrition : the middle-most ( or the breast ) wherein is the work-house of life , and the fountain of heat : the highest ( or the head ) in which the animall spirits , and in them reason , the image of god , inhabits . there is an analogy betwixt the parts of the world , and the parts of the body . for example ; flesh represents the earth ; bones the stones ; bloud and other humours , waters ; vapours , of which the body is full , the air ; the vitall spirit , the heaven , and stars ; the haires , plants ; but the seven planets are the seven vitall members in our body : for the heart is in the place of the sun ; the brain , of the moon ; the spleen , of saturn ; the liver , of jupiter ; the bag of gall ; mars ; the reins ; venus ; the lungs , mercury , &c. lastly , certain creatures shew forth their virtues in certaine parts of the body . for example , some herbs cure the lungs , some the liver , &c. which shews a certain analogy of the microcosme to the macrocosme , though not well known to us . xxii also man is not absurdly called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or the all ; because ; he hath his body from the elements ; his spirit from heaven , his mind from god : and so in himselfe alone he represents the visible and the invisible world . man is all , because he is apt to be all ; that is , either most excellent , or very base . for if he give himselfe to earthly things , he becomes brutish , and falls back again to nothing : if to heavenly things , he is in a manner deified , and gets above all creatures . chap. xii . of angels . we joyn the treatise concerning angels with the physicks ; because they also are a part of the created world , and in the scale of creatures next to man ; by whose nature , the nature of angels is the easier to be explained . therefore we will conclude it in some few aphorismes . i there are angels . divine testimonies , and apparitions testifiè that : and also a three-fold reason . vapours , concretes , plants , living creatures are mixt of water and spirit . now there is matter without spirit ( the pure element ; ) therefore there is spirit also without matter . as the matter of the world is divided into four kinds , ( the four elements ) so we see already the spirit of the world to be distinguished into the naturall , vitall , animall , and mentall spirit . now the lowest degree is to be found alone ( as in concretes . ) therefore the highest may be found alone , to wit , in the angels . every creature is compounded of entitie , and nihility . ( for they were nothing before the creation : but now they are something ; because the cretour hath bestowed on them of his entitie , more or lesse by degrees . by how much the more entitie any thing hath , so much the further it is from nihility : and on the contrary . ) seeing then then that there is the first degree from nihility , ( that is a chaos , the rudiment of an entitie : ) without doubt there is the last also , which comes nearest to a pure entitie . but man is not such : because having matter admixt , he partakes much of nihility . therefore of necessity there is a creature , with which , materiality being taken away , all other perfections remain . and that is an angell . ii an angell is an incorporeall man. an angell may be called a man , in the same sense that man himselfe is called an animall , and an animall , a plant ; and a plant , a concrete , &c. ( as we have set down in their definitions : ) that is , by reason of the forme of the precedent included , with a new perfection only super-added . for a man is a rationall creature made after the image of god , immortall : so is an angel , but for more perfections sake free from a body . therefore an angel is nothing but a man without a body : a man is nothing but an angel clothed with a body . but that angels are incorporous , appears because although they be present , they are not discerned neither by the sight , or any other sense . because they assume to themselves earthly , watery , aery , fiery , or mixt bodies , as need requires ; and put them off again ; which they could not do , if they had bodies of their own as we have . yet ordinarily they appear in an humane forme , by reason of the likenesse of their natures , as we have said . iii angels were created before all visible things . that was shewed in the apendix of the first chapter : you may see it again , if need be . and moses words are clear : in the beginning god created the heaven and the earth : and the earth was void . see the earth was ( in that first production ) emptie and void ! therefore heaven was not void : then it was filled with its host , the angels . iv the angels were created out of the spirit of the world . as moses seems to comprehend the production of angels under the name of heaven , so also the universall spirit . for he ●oth not say , that this was created with the earth : but he pronounceth abruptly after the creation of the earth , that the spirit of god moved it selfe upon the waters : intimating thus much that it was in being before . we conclude , therefore that the angels were formed out of that spirit ; so that part of that spirit was left in the invisible heaven , and shaped into meer spirituall substances , [ angels ; ] and part sent down into the materiall world below . after the same manner , as the fire was afterward partly left in the skie , and fashioned into shining globes : and partly sunk into the bowels of the earth , for the working of minerals , and other uses . that which follows makes this opinion probable , ( if not demonstrable . ) principles should not be multiplied without cause . seeing therefore that the scripture doth not say , that they were created out of nothing , nor yet names any other principle , why should we not be satisfied with those principles that moses hath set down ? angels govern the bodies which they assume , like as our spirit inhabiting the matter doth : therefore they are like to it . there is in angels a sense of things , as well as in our spirits . ( for they see , hear , touch , &c. though they themselves be invisible , and intangible . also they have a sense of pleasure and griefe : for as much as joyes are said to be prepared for the angels , and fire for the divells , ( into which wicked men are also to be cast . ) although therefore they perceive without organs , yet we must needs hold that they are not unlike to our spirit which perceiveth by organs . v the angels were created perfect . that is finished in the same moment , so that nothing is added to their essence by adventitious encrease . for being that they are immateriall , they are also free from the law of materiality : that is ( when a thing tends to perfection ) to be condensed , fixed , to encrease , and so to be augmented , and become solid by certain accessions . vi angels are not begotten . men , animals and plants , are generated , because the spirit included in the matter , diffuseth it selfe with the matter , and essayes to make new entities . but an angel being that it is without matter , and its essence cannot be dissipated , hath not whether to transfuse it selfe . hence christ saith , that in heaven we shall be as the angels , without generation , or desire of generation , mat. . . vii angels die not . the spirit of animals and of plants perisheth , because when the matter ( that is , its chariot ) is dissipated , it also is dissipated . but an angell having his essence compacted by it selfe , without matter , cannot be dissipated : and therefore endures . viii the number of angels is in a manner infinite . see job . v. , . yet daniel names thousands of thousands , and myriads of myriads , dan. . . as also john , apoc. . . ix the habitation of the angels is the heaven of heavens , mat. . v. . and . v. . therefore they are called the angels of heaven , ( gal. . v. . ) and the host of heaven , ( king. . v. . ) for it was meet , that as the earth , sea , air , and skie , have their inhabitants , so also that the heaven of heavens should not be left empty . yet they are sent forth from thence for these following ministeries . x god created the angels , that they might be , the delight of their creatour . the supream spectatours of his glory . his assistent ministers in governing the world. the scripture teacheth this every where : but they also point at names given them . the first appellation of angels is in gen. . v. . cherubim , that is , images : wherein is intimated that they were made after the image of god , as well as men but note what it is to be made after the image of god. the essentiall image of god , or the character of his substance , is the son , his eternall wisdome , heb. . v. . after the likenesse of him therefore , men and angels are said to be created : that is , made understanding creatures : in which respect also they are called the sons of god , job . . v. . seeing then that an image delights him , whose image it is , it is intimated that god made the angels primarily for himselfe , that he might have some , who being cohabitants with him , might behold his glorious majesty face to face , and be partakers of eternall beatitude . now the most common name of angels in the old testament is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 malachim that is , embassadours : in the new testament 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , that is , messengers ; because god created these to be rulers and governours of the world. for whensoever the course of nature is to be hindered , or any thing is to be wrought beyond the ordinary order of nature , god useth their assistence . for example , when the fire was to be cooled , that it should not burn , ( dan. . v. , . ) or the mouthes of lions to be stopped , that they should not tear daniel , ( dan. . v. . ) or the enterprises of the wicked to be hindered , ( numb . . v. . ) or any to be killed by a sudden death , ( exod. . v. . and chron. . v. . and chron. . v. . and acts . v. . ) or the godly to be delivered from danger , ( gen. . v. . ) or travellers to be guided in their way , ( psal. . v. . ) or to be preserved in any chance , lest they should be dangerously hurt , psal. . . or to be warned any thing in a dream , or otherwise , mat. . . &c. hence they are thought also to be added to certain persons peculiarly , ( heb. . ● mat. . . acts . . ) that they may accompany them every where , ( psal. . . ) and be witnesses of all our actions , ( cor. . . tim. . . ) but especially that they are sent to defend kings and kingdoms , ( dan. . . &c. ) hence also they are called , watchers or keepers , ( dan. . . . ) xi angels can act upon bodies , but they cannot suffer from bodies . both these appear by the effect . for angels bear about , move and governe the bodies which they assume : but those that are separated , they overthrow , stay and move from place to place with externall violence , at their pleasure ; yet they themselves in the mean time can be hindred or stayed by no body . xii the powerr of angels exceeds the strength of any corporall creature . for it operates without resistance of the objects by penetrating . without endeavour or enforcing , being that they are not deteined or hindred by their own body , as our spirit is : which being tied to the body , must of necessity draw it along with it laboriously , as the snail doth her shell . hence the angels are called mighty in power , ( psal. . . ) and powers , principalities , dominions , ( col. . . ) xiii the agility of the angels is greater then of any corporeall substance . hence they are compared to wind and to fire , and to lightning , psal. . . ezech. . . luke . . and they are called seraphim , that is , flamy , isai. . . yet it is certain that they move swifter then wind or lightning , when they passe any whither . for the wind and lightning penetrate the air , not without resistance , but an angell , being a meer spirit , doth it without any resistance . it appears then , that though an angell be not in many places at once , ( dan. . . . ) yet they can in a moment passe themselves whither they will. hence it is that one angell was able to slay a whole army in a night ; and also to smite the first born of the aegyptians , throughout all the kingdom , isai. . . exod. . . and sam. . . xiv the knowledge of angels is far more sublime then mans . and that because of the clearnesse of their understanding , which nothing obumbrates . by reason of their power to penetrate any whither , and see things plainly . because of their long experience for so many ages . ( whereas we are but of yesterday , job . . ) and yet they are not omniscious . for they know not the decrees of god , before they be revealed . future contingents . the thoughts of mans heart . ( jer. . . . ) that is , so long as they are concealed in the heart . for when they are discovered by gestures & effects , they discern them . for if we by the effects , are not altogether ignorant of their thoughts ( cor. . . ) wherefore should not they be a thousand times more quick sighted upon us . n. w. how that part of the angels falling into evill , exercise perpetuall hostility with mankind : and god makes use of them to be as it were executioners to wicked men : but hereafter he will condemne them both ; in like manner , as good men are to enjoy the association of good angels : and lastly , how the frauds of those are to be avoided , but the presence of these to be procured , to teaach that belongs to sacred divinity . the epilouge . thus we have seen that the created world is a meer harmony . all things by one , all things to one ; the highest and the lowest , the first and the last , most straightly cleaving together , being concatenated by the intermediate things , and perpetuall ties , and mutuall actions and passions inevitable , so that the world being made up of a thousand thousand parts , and particles of parts , is neverthelesse one , and undivided in it selfe ; even as god the creatour thereof , is one from eternity to eternity , nor ever was there , is there , or shall there be any other god , ( isai. . . &c. ) and we have seen that all these visible things are made out of three principles , matter , spirit , and light : because he who is the beginning and the end of all things , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , that thrice blessed and omnipotent god three in one , is he of whom , and through whom , and in whom are all things , rom. . . we have seen also that admirable scale of creatures , arising out of the principles , and ascending by a septenary gradation . for we have understood , that whatsoever there is besides god , it is either an element , or a vapour , or a concrete , or a plant , or an an●●all , or a man , or an angell ; and that the whole multitude of creatures , is ranked into these seven classes , or great tribes . in every of which there is some eminent virtue flowing from the essence of the creatour ( yet every latter including the former . ) for in elements , being is eminent . vapours , motion concretes , figure , or quality plants , life . living creatures , sense . men , reason . angels , understanding . see the house which wisdome hath built her , having hewn out her seven pillars ! ( prov. . . ) see the seven stairs which the king of heaven hath placed in the entry of his inner house ! ezek. . . the six first degrees are of visible creatures , the seventh of invisible angels : after the same manner , as there were nine dayes wherein god wrought , and rested the seventh ; six planets in heaven of inferiour light , the seventh of extraordinary brightnesse , the sun ; six baser metals on earth . the seventh exceeding all in perfection , gold , &c. and as salomons throne had six inferiour steps to every of which there were six inferiour leoncels adjoyned : after all in the seventh place stood the throne , and by it two lions ( king. . , . ) so the king of eternity , when he built him a visible throne of glory , erected six visible degrees of corporeous creatures , to every of which he added their leoncels , that is , their virtues , and their powers , and last of all , about the throne on high , he placed the strongest of the creatures , the angels mighty in power , ( psal. . , . ) but now what mean the seven planets in heaven ? what mean the seven continents on earth ? the seven kinds of meteors , seven kinds of metalls , seven kinds of stones , & c ? the seven combinations of tangible qualities ? the seven differences of taste ? the seven vitall members in man ? the seven tones in musick ? and other things which we meet with throughout all nature ? yea , and in the scripture the number of seven is every where very much celebrated , and sacred : for what do the seven dayes of the week point at ? what are the seven weeks betwixt the passeover and pentecost ? what the seventh year of rest ? what the seven times seventh of jubilee ? what do all these portend i say , but that it is , the expresse image of that god whose seven eyes passe through the whole earth ? ( zach. . . ) and whose seven spirits are before his throne , ( apoc. . . ) yea , who doth himselfe make a mysticall eighth with every degree of his creatures . for in him all things live , aud move , and have their being ; which live and move , and have a being ( acts . . ) and he worketh all in all , ( cor. . . ) and all these are as it were him himselfe , ( eccles. . . ) and yet none of them is he himselfe , ( job . . . ) but because all these have some effigies of the divine essence , and operate that which they operate by virtue thereof ; hence it is , that he being above all , without all , and beneath all , is the true mysticall eighth of all . of whom ( that syracides may conclude our meditation , though we say much , we shall not yet attain thereto . the sum of the doctrine is that he is all . for what ability have we to praise him ? for he is greater then all his works . the lord is terrible and very great , & marvellous is his power . extol the lord in praise as much as you can : for yet he wil be greater then all praise , ( eecl . . &c. ) therefore let every spirit praise the lord , hallelujah . ( psal. . ) and thou my soul praise the lord ( psal. . . ) holy , holy , holy , lord of hosts ! heaven and earth are full of his glory , ( isai. . ) hallelujah . a short appendix to physicks . touching the diseases of the body , mind , and soul , and their generall remedies . i. a disease is the corruption of an entity in some part thereof , and a disposition of it to totall perishing ( that is death . ) therefore both the body , mind , and soul , hath its diseases . ii the diseases of the body are various , scarce to be numbred ; and oft-times m●●t . a disease added to a disease is called a ymptome of a disease . iii a disease of the body is either by solution of that which is continued , or by distemper of humours . iv solution of that which is continued , is either by a rupture , or a wound . a rupture is prevented by bewaring falls , and violent motion . a wound is avoided by shunning of those things , which can cleave , cut , prick , rent , tear or bruise , or hurt anyway : and both are to be cured by the chirurgion . n. w. the cure of a wound , is desperate , if any vitall member be hurt : as the heart , the brain , the liver , the entrals , &c. for then the vitall actions are hindred , and soon after cease . if any member be quite lost , it cannot be set on again : because the spirit hath not wherewithall to passe into the part that is severed . v the distempers of the humours and the diseases that come from thence , always proceed from some of these causes : namely , either from crudity inflation distillation obstruction putrefaction inflammation vi crudity in the body is nutriment not sufficiently concocted : namely either chyle , or bloud , which comes i from the quality of meat and drink ; when they are taken too raw , flegmatick , unwholesome , which the concoctive faculty cannot well subdue . from the quantity : when more meat and drink is put in , then it is able to alter and assimilate unto the body . for hence undigested and not assimilated humours , burthen the body , like strangers , and not pertaining thereunto . for want of exercise : when the naturall heat is not stirred up , nor strengthened to perform its office lustily in the concoction of meats . from such like crudities diverse inconveniences follow . for if the crudity be in the stomack , it causes loathing of food : for so long as the first food is not digested , there can be no appetite to any other . again , children have an appetite to eat earth , chalk , coales , &c. according as the crudities are turned into the likenesse of any matter . for like desireth like . if there be a viscous crudity adhering in the ventricle or in the guts , being warmed it takes spirit , and is turned into wormes ; which gnawing the bowels stir up evill vapours by their motion : whence also come phartasies , very hurtfull to the head . lastly , ctudity under the skin , ( in the bloud and flesh ) begets palenesse : and when it is collected and putrified ; scabs , ulcers , &c. crudity is prevented by a temperate diet . as to food , sleep , and daily exercises : and cured by violent expurgation . by strong exercises . by the use of tart meats and drinks . by comforting the stomack with such things , as heat , both within and without . vii inflation is much and grosse vapour , exhaling from the crudities that are gathered together , and stretching the members . and that either without pain as when it causeth yexing or belching in the ventricle ; panting in the heart ; giddinesse in the head ( when being prohibited to go any further it is carried in a round ) lazinesse and stretching in the whole body ; or else with pain , as when it causeth aches in the bowels ( straightning the spirits that lie between in the fibres ) and shurp or else blunt prickings in the muscles , according as it is more grosse or subtile it is cured by strong exercise , that the vapour being attenuated , may go out at the pores opened . by expurgation of the humours by which they are generated . viii distillation is the condensation of crude vapours into rheume , which is the cause of many evils . for crude vapours gettting up to the head , when as by reason of the abundance and grossenesse of them , they cannot be expurgated by the ordinary passage , they become rheume flowing severall wayes , and rausing diverse diseases . for if they run abundantly , and 〈◊〉 at the nose , they cause the murre or pose , if the distillation fall into the jawes , it causes the catarrhe . if into the kernels of the jawes , the quinsie . if into the lungs difficulty of breathing , and the asthma . if the distillation be salt and sharp , ulcerating the lungs , it causes the cough . which if it be done oft , and the lungs be filled with apostemes , it causes the consumption . for when the ulcerous lungs cannot with dexterity enough perform their office of cooling the heart , the vitall spirit is generated more hot then it should be , which doth not cherish , but feed upon the flesh and bloud , and at length burns out the very workhouse it self of the bloud , which is , the liver : whence for want of bloud , which is as it were the food , followes the consumption of the whole body . if the distillation flow in abundance , and grosse down the marrow of the back , it causeth the palsie , ( by hindring the animall spirit , that it cannot be distributed by the nerves springing from the back bone . ) if it fill the nerves of the muscles only , it becomes the spasma , or convulsions ( that is when the nerve is contracted , like as a chord being wet and dried again , is wont to be contracted , and become shorter . ) if it flow subtle , and penetrating the nerves , it is at length gathered together in the extremities of the members , and there raises sharp pains ; which in the feet are called the gout ; in the hands , chiragra , or the hand-gout ; in any of the joynts of the bones erthritica , the running gout ; in the hip , it is called ischias , or the hip-gout , commonly the sciatica lastly , if those kind of runnings stay in the head , they procure divers diseases : as when they are subtle , the head-ach . too raw and flegmatick , the lethargie . salt , and cholerick , the phrensie . grosse and mixt with a melancholy humour , the epilepsie , or falling-sickness , ( when as the spirits diffused through the whole body , making haste to relieve the spirits befieged in the brain , make most vehement stirs , and fight , till they either overcome and repell the disease , or else faint and are extinguished . but if the grosse phlegmatick humours have occupied all the vessels of the brain at once , it becomes the apoplexie , that is , a privation of all sense and motion : whence also the vitall fire in the heart is soon after extinguished . all these diseases are both prevented , and also ( if they go not too farre ) cured by exercise . by rectification of the brain by good smels . by a thin , hot , and sulphury air . by thin , light meat and drink . but the peculiar cure of every disease is committo the physiciaus . ix obstruction is a stopping of the bowels by thickned flegme , whence it comes to passe that they cannot execute their office . for example , when the entrals are stopt , that they cannot void , it is the volvuls , or wringing of the guts : when the liver is stopt , the dropsie ; ( for the chylus being not turned into bloud , flowes through the veins and members , and is not turned into members . ) when the bladder of gall is stopt , the yellow jaundise ; when the spleen , the black jaundise ; ( for in the first the choler , in the other the melancholy , when it cannot be voided , diffuseth it selfe through the bloud . but when the urine pipes , or the 〈◊〉 , or the bladder are stopped , that is by reason of the breeding of tartar , which they call the stone : which stopping the passages , by its sharpnesse pains the veins and nerves . the cure is by purgations . by medicines attenuating , or breaking , cutting , and driving out the grosse humours which physicians know . x putrefaction is the corruption of some humour in the body : namely , either of flegme , or of choler , or of melancholy ; which putrifying either in or out of their vessels , produce feavers or ulcers . the cure is expurgation of the place affected . a good diet . motion . xi inflamation is a burning of the vitall spirit ( n. vitall ) or of the bloud caused by too much motion ( either of the body by wearying it , or of the mind , by musing and anger , ) or else by putrefaction , or else by obstruction . for it is known out of the physicks , that motion doth heat even unto firing , and that by obstruction doth 〈◊〉 an antiperistasis exasperate the heat included ( even in these things that are watry and p●trid ) so that at length it breaks out violently , hay laid up wet , ( when it cannot get transpiration ) doth shew . when the bloud is kindled within , it becomes a feaver : when under the skin , s. anthonies fire . the generall cure is the opening of a vein , and cooling . but of feavers ( being that it is a most common disease , and of divers kinds ) something more is to be said . xii the feaver so called , from its fervency or heat , is of three kinds . the ephemera . the putrid . the hectick . the first burns the spirits ; the second the humours ; the third the solid parts . the first like a raging hot wind scorching all it meets with : the second like boiling water poured into a vessell , which it heats with it selfe . the third like unto a hot vessell , heating the water poured into it with it selfe . for the hectick occupies the bones and membranes , and eats and consumes them with an unnaturall heat , by degrees almost insensibly , till at length it causeth death . it is very like the consumption . but the putrid or rotten feaver occupies the bloud and humours ; by which the whole body grows hot . the ephemera is a more subtle flame , feeding upon the spirits only : and therefore it scarce endures one or two days , til the peccant cause be consumed by the spirit it self . hence either health or death usually follows within two or three dayes ; and therefore it is called the ephemera or diary feaver : also the maligne feaver . of which sort also is the pestilentiall infection : for it comes after the same manner . putrid feavers are most usuall , but with very much difference : for when the humours putrifie within their vessels , ( or workhouses ) especially near the heart , ( in the liver or the gall , ) the spirit rises against them , and kindles them : and ceases not to assault them , till it either expell the rottennesse being turned into soot , or be extinguished it selfe ; and therefore this feaver is often deadly , it is called the continuall feaver . but if the humours rot out of their vessels , that is , in the veins or members , it is an intermitting feaver . for the spirit riseth up at certain times , and opposeth that rottennesse with heat : but because this battle is made further off from its castle , the heart , when the fight is ended , it returns home . and if the putrifying humour be flegme , it still returns to oppose it the next day : hence the quotidian feaver . if it be yellow , choler ; then every third day . hence the tertian . if black choler , the fourth day . hence the quartan : the cause of the inequality , is because the flegme recollects it selfe soonest , and makes new businesse for the spirits : but is withall sooner dissipated : hence the quotidian lasts not long . melancholy being that it is a dreggy humour , doth not so soon recruit it selfe : but because it is soft and viscous , it is not so easily overcome : hence the long continuance of quartans , in the tertian , because the spirit opposeth yellow choler , which is hot of it selfe , is made the hottest fight : hence tertians are called burning feavers . they are sometimes changed one into another , or one joyned with another , according as one while one putrified humour , another while another is to be opposed . hence it appears why a feaver begins with cold ? because the vitall spirit being to oppose the rottennesse , gathers heat as it were its aid from every part , the outward members in the mean time being benu 〈◊〉 and quaking with cold . ( for even in too much fear , when the spirit gathers it selfe into the inward parts , there is wont to follow a chilnesse of the outward members , and a quaking with cold . ) whence afterwards heat ? because the spirits , after they are hotter with fight and motion , return again to the members ; which , being cold before , do so much the worse endure the heat , returning now hotter then ordinary . why the feaver leaves faintnesse behind it ? because the spirit wearied with fight , betakes it selfe to rest , leaving the members destitute . why food is hurtfull at the beginning of a feaver ? because when the spirit is preparing it selfe for the battell , it hath another businesse put upon it , ( to concoct the food : ) but seeing that it is not able to do both , it either assaults the disease more weakly , or else leaves the food unconcocted : or at least , if it do both , it weakens and tires out it selfe too much . why it is dangerous to expell the feaver over soon ? because the feaver is of it selfe a benefit to nature , driving away the rottennesse in time , left it should at length prevaile and oppresse the heart . therefore that is no good cure of feavers which stayes the fits , but that which ripens the rottennesse for expulsion : and strengthens nature to oppose them , which i leave to physicians . let this be the sum of that which hath been said , crudity is the seed of all diseases . for thence gross vapours arising , cause inflation , the same condensed in the head , cause , distillation : in the other members , obstruction : whence flowes either rottennesse or inflamation . therefore let him that prevents crudities , believe this ; that he takes the best cours that may be for his whole body . now the way to prevent them is a temperate diet and daily exercises . o the strange virtue of labour , whereby we get both our bread and health ! which mistery if the slothfull understood , they would not waste their lives with idlenesse . of the diseases of the mind . i the diseases of the mind are vices , procuring either disquiet , or griefe thereto . ii diseases disquieting the mind , are evill desires ; that is , too much ardency . of living . of eating and drinking . of multiplying it selfe . of knowing . of having . of excelling . n. w. these are thus expressed by their proper names , selfe-love . intemperancy . salacity . curiosity . covetousnesse . ambition . for they that are given to these , itch and are disquieted continually . iii the diseases that cause griefe to the mind , are immoderate affections ; that is violent alterations for those things which befall us according to our desires , or contrary thereto : but especially sadnesse , angor , and at i●ksomnesse of life . iv the remedies of the mind are held forth in the ethicks . the sum where of comes to this . love the golden mean , shun extreams like unto precipices . never desire to do more then thou canst : remember that thou art a man. for that may befall every one that befalls any one . there is a vicissitude of all things , an unconquered mind overcomes all things , &c. of the diseases of the soule . i the diseases of the soule are , forgetfulnesse of god , torment of conscience , and despair of mercy . ii forgetfulnesse of god is cured by the fear of god. of , i say , that god , who seeth all , judgeth all , rewardeth all , to every one according to his works : to avoid whose hand , it is impossible . ( for in him , we move , live , and have our being , ) but to endure it is intolerable . ( for he is a consuming fire , &c. ) iii torment of conscience is healed by prayers , and and study of innocency , psal. . . eccl. . , . for if our heart condemn us not , we have full assurance , &c. john . . iv despair is healed by the bloud of that onely lamb of god , which purgeth us from all sin , joh. . . and reconciles us to his father , rom. . . and saves us , rom. . . and gives us eternall life , joh. . in body sound , amind as sound , o god we pray thee give , that here in peace , in after blisse ; for ever we may live . finis . natural philosophy improven by new experiments touching the mercurial weather-glass, the hygroscope, eclipsis, conjunctions of saturn and jupiter, by new experiments, touching the pressure of fluids, the diving-bell, and all the curiosities thereof : to which is added some new observations, and experiments, lately made of several kinds : together with a true relation of an evil spirit, which troubled a mans family for many days : lastly, there is a large discourse anent coal, coal-sinks, dipps, risings, and streeks of coal, levels running of mines, gaes, dykes, damps, and wild-fire / by g.s. sinclair, george, d. . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing s estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) natural philosophy improven by new experiments touching the mercurial weather-glass, the hygroscope, eclipsis, conjunctions of saturn and jupiter, by new experiments, touching the pressure of fluids, the diving-bell, and all the curiosities thereof : to which is added some new observations, and experiments, lately made of several kinds : together with a true relation of an evil spirit, which troubled a mans family for many days : lastly, there is a large discourse anent coal, coal-sinks, dipps, risings, and streeks of coal, levels running of mines, gaes, dykes, damps, and wild-fire / by g.s. sinclair, george, d. . [ ], , [ ], p. : ill., plates. ... are to be sold by gideon shaw ..., edinburgh : . reproduction of original in huntington library. attributed to george sinclair. cf. bm. table of contents: p. [ ]-[ ] errata: p. 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ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . astronomy -- early works to . - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - emma (leeson) huber sampled and proofread - emma (leeson) huber text and markup reviewed and edited - pfs batch review (qc) and xml conversion natvral philosophy improven by new experiments . touching the mercurial weather-glass , the hygroscope , eclipsis , conjunctions of saturn and jupiter . by new experiments , touching the pressure of fluids , the diving-bell , and all the curiosities thereof . to which is added , some new observations , and experiments , lately made of several kinds . together , with a true relation of an evil spirit , which troubled a mans family for many days . lastly , there is a large discourse anent coal , ●oal-sinks , dipps , risings , and streeks of coal , levels , running of mines , gals , dykes , damps , and wild-fire . by g. s. ars longa , vita brevis . printed in the year , . and are to be sold by gideon schaw bookseller , at the sign of the bible , in the parliament-closs , in edinburgh . to the right honourable s r. james fleming , lord provost of edinburgh , george drumond , david lindsey , iames nicolson , and george sinclar bailiffs , archibald hamilton , dean of gild , thomas young , thesaurer , william borthwick , deacon conveener , and remanent members of the honourable council of the said burgh ; in all humility offers and didicates this philosophical tranasaction , george sinclar professor of philosophy and mathematicks . may it please your lordship , and the honourable senate , i present you with a mean oblation , less than the widows mite , but with a willing mind . 't is all i can afford at present . farre li●abit , qui non habet , thus : who wants frankincense , must sacrifice with bear-meal . i have sometimes offered more to others , who were not so deserving . i still remember how kindly the council treated me for some years ago . when i taught the mathematicks at edinburgh ; and what a singular obligation they conferred upon me after , when i was employed to search out a well , which by good providence i lighted upon , which is now a well-spring of happiness to the good-town . i made several observations , with a most accurate , and exact level ; but especially one from the highest ground in the castle , in the evening towards the fountain , by the help of a light there , on the . of may , . which gave infallible assurance to the magistrates , that the source was . foot higher than the weigh-house , and great encouragement to the council to begin the work. it is registrate in scripture , as one of the great acts of hezekiah , that he made a cistern , and a condu●t , and brought water into the city of jerusalem . this work will be extant among the annals and chronicles of the city , of things done from year to year , to all generations , which is the glory also of the succeeding magistrates . but your wisdom and prudence in governing the city , and composing all differences , and setling all matters every day so happily , is of far greater moment . this transaction explains the weather-glass , and hygroscope , which are in great esteem , even among kings , and princes . his royal highness put no small value upon that which i presented to him. non equidem tali me dignor honore . i now crave pardon , that i have adventured to prefix your names to the frontispice of this mean pamphlet , between which , and your incomparable merits , there is no proportion . all i can do , is to pray , that your lordship and council may live to be , as you are , the glory and credit of the place , and that you may slowly , yet surely exchange at last , this mortality with immortal life . this i fervently wish , while i am your honours most humble , and much obliged servant , george sinclar . leith , ianuary . . the explanation of the weather-glass . i have set down the theory of the weather after this manner . in the first , and upmost station , thirty inch and a half , above the cistern , is long fair , or most pleasant weather , as the poet sings , totus & ille dies , & quin ascentur ab illo , exactum ad mensem , pluvia ventisque carebunt . this day and all , which after it remain , f●r th●●ty day● , sha●l want both wind and rain . the metal being at this height , which i rather find to be in winter , than in summer , the heavens are clear : yet sometimes covered with dry and gray clouds , but not the least appearance of rain . nothing for several days after , but setled calm weather , as dry and hard frost in winter , with a clear sky : sometimes the air most pure , and clear without frost . here it was upon thursday , october . 't is seldom so high , because we in this countrey have not often , a most pure , and clear air , as in france , and other parts of the world ▪ if the metal ascend to this station , it is an evident token , that the glass , is right mounted , and adjusted . i call the second station , which is half an inch lower , fair , or dry and fair. ●ace serenato clar●m juhat emicat ax ▪ p●●gatusque nitet di●●ussis ●u●ibus ●●ther . behold a ray , tha● 〈◊〉 breaks forth from se●●n● hea●en and purged sky doth shine , all cloud 〈◊〉 that 's been . the quick-silver being at this station , the weather is good ; but not so setled , especially in the winter-season . i have oftentimes observed a small thin showre of rain to fall , for some hours together , from the lowest region of the air , as a thick dew or mist , but immediatly after , the day became clear and fair , the air being under a strong disposition to be so . the third station , half an inch lower is changeable , sometimes fair , sometimes foul , sometimes frost , sometimes thaw , sometimes sleet , sometimes snow , sometimes wind , sometimes calm . nun● pluit , & clarus , nune iupiter aethere surgit . sometimes ●oul jove , doth wring the clouds for rain , sometimes fair jove , appears in heaven again . the fourth station is rain , or rainy weather ; not that it rains always , but that there is a strong inclination in the air , to be rain . — madidl● notus evolat all● , terribilem pleca tectus caligine vultum , barba gravis nimbi● , can●s ●uit unda capillis . out flyes the south , with dropping wing● , who shrouds , his 〈◊〉 aspect in the pitchy 〈◊〉 . his white● air streams , his bea●● b●g . ●●●oln with shor●● ▪ m●●ls bi●● hi● bro● , rain from his boso● pu●●●es , i call the fifth station , much rain , or very foul , as in the summer , or winter-time , when rain is accompanied with strong s. w. and w. winds . this is bad weather indeed , both by sea and land. — et den●i ●unduntur ●● aethere n●●bl ▪ ecce cadunt ●argi , reselusia nubibu● , imbre● inquetreom credas totum descendere coeluth . 〈◊〉 of rain , are poured from the heaven , waich●●ken phenus , and his peir●ing beams . 〈…〉 great 〈◊〉 did fall , some thought the heavens to sea , were tu●bled all . to this station did the mercury fall down , on monday , november . and sunday night , november , being two inch lower , than october . the sixth station is stormy , the worst of weather in this country . tum mihi ●ae●ule●● , supra caput astitit imber , n●ctem hyememque ●erens , & inhorruit und● tenebris . a purpur● showre did canopy my head . dark winter came , and waves grew black indeed ▪ i have subjoyned in the last place tempests , or hirricanos , which do not fall out in this country . they are lively described by the poet. — acvent● , velut agmine f●cto , qua data por●●●unt , & terras turbine per●●●nt . incubuere mari , to●●mque a sell●us im●s . una , eu●u●que , no●●sque en●nt , cre●erque procel●●a africus , & vasto● volvunt ad littora fluctus ▪ tempect●●●ine more ●urit , ton●●●●que tren●seunt . ardua terra●um , ●●●pique & littora circum . — winds at his mutinous ●ands force their own way , and thunder through the strands . they take the sea , eurus and notus raves , and stormy africus from deepest c●ves . when temp●storage , and joves great cannons rea● , the mountains quake , the plains , and every shoar . the first rule is , the further up the metal goes , the weather inclines to be the fairer , and the further it falls down , it inclines to be the fouler . secondly , when it is heighest , fair weather is universal , when it is lowest , foul weather is universal . thirdly , 't is not so much fair or foul weather actually , which influences the quick-silver , as it is the disposition , and inclination of the weather , to be fair , or foul. note , that n. e. and e. winds , even with ra●n , do raise the mercury , and keep it up sometimes beyond ordinary . and as it shews the nature of the weather , so it foretells ; which is the great excellency of it , sometimes a day , sometimes two , sometimes three or four , before any change of weather come . the metal rises and falls quickly , when fair or foul weather is nigh at hand . it doth not so much foretel winds , as it is actually influenced by them , when they blow , in causing the metal subside and fall down . 't is said , that the ladies and gentle-women at london , do apparel themselves in the morning , by the weather-glass . whatever be in this , 't is certain , that when a man riseth in the morning , he may know infallibly , what sort of weather , will fall out ere night . it is not possible to make it unerring , unless it be mounted , and set up by a skilful hand , which few or none can do . the inclosed weather-glasses , are ten dallers , the open ones thirty shillings , which are as true . none from abroad are so accurately made . neither any such are sold , at so easie a rate . they may be transported , and carried to any part of the country , and there set up , by my directions . the explanation of the hygroscope . this second is a curious invention , which i call the hygroscope . the the name is made up of two greek words , hygros wet , and scopeo to view or consider : because we know by it , the several degrees of moisture , and dryness in the air. it is mean to look upon , being but the awin , and beard of a grain of oats . it is twisted , and twined by nature , as the lute string , or a silk cord is twined by art. it is secured within a round box , whose inside is divided into . equal parts . there is affixed to the top of it , a small slender glass-index , which goes about with the awin , as it is altered with the moisture , or dryness of the air. the motion is direct , or right about , following the course of the sun , with moisture , and retrograde , or left about , with dryness . it is likewise stationary , or standing , when the air is setled , as to wetness , or dryness . it is of all of all things , in the universe , so far as i know , most affected and sensible of humidity and s●●city . many curious philosophical questions do arise from its several operations ▪ which would trouble oedipus himself , to resolve . i have found the index , from wet air in extremity , to dry air in extremity , make six revolutions . for this cause , i have contrived a little broad , with six circles upon it , or rather spirals , divided equally into . parts , as the inside of the box is , by the help of which , a man may trace the motion of it , all the year over , most easily , whether it be direct , or retrograde . you will find these advantages by it . wet air in extremity , dry air in extremity , air equally moist and dry , wet air , dry air. it discovers the least difference of air between one room and another . it is much influenced with winds from the north , especially in frost , which make it retrograde , and with winds from the south , which make it direct and move right about . in a years time , it makes several revolutions . the motion is most sensible , for sometimes in one night , it will alter . degrees , o● the fourth part of a circle . it not only shews the present temperament of the air , which is a great advantage , but foretels . nay , which is admirable , i have found it sometimes foretel fair weather , when it was actually raining . it keeps a correspondence with the weather-glass . there is great difficulty to know what revolution it is under , from wet air in extremity , or from dry air in extremity , for fixing the brass-pin in its own proper circle . the husk or hool , of the mouse-pea , ( as we call it ) or the wild vetch , will make a hygroscope , but it is somewhat dull and slow , and goes not so oft about , yet very sensible of the wetness , and dryness of the air. when the index of the hygroscope , is altered by the weather , it keeps not a continued motion , but sometimes moves backward , and sometimes forward ; yet at length perfects its course right about , in so many months , and returns again in so many . among the many difficulties which occur , this is one , what is the reason , why the awin goes alwayes right about with moisture , and left about with dryness ? to say , that it is so ordered by nature , is ridiculous . the same difficulty we find in the shells of snails , whose screw , and spiral line , goes right about , with the sun , and in the shells of sea-snails , commonly called buckies . some affirm , that upon the south of the line , the shells of these creatures , are screwed left about , which is worthy of observation . 't is easie to give the reason ▪ why a lute string turns about such a way with moisture ; because , while it was twined by the artist , the wheel or spindle went such a way about , wherewith he twisted it . but who can say the like of the awin , seing the great artist is god , and nature , whose working and manner of working is unknown to us . 〈◊〉 be asked , what way goes about the hool of the wild vetch ? i answer , which is a notable speculation ▪ the one hool , goes right about with the sun , by moisture , as the awin doth , and consequently left about , with dryness . but the other goes right about with dryness , and left about with moisture , contrary to the motion of its fellow hool . this is seen sensibly , by holding them nigh the fire . the same holds true , in the two hools of the right pea-cod . i suppose that the hools of brom-seed , may do the like . another experiment i made with the hygroscope , in placing it , within the receiver of the air-pump . at the very first exsuction of the air , the index moved left about most sensibly , and by the several exsuctions , which were made one after another , it advanced , half a circle about . it had been easie to have made it go right round once , if i had continued pumping . here is a phenomenon to be salved , and well worthy the pains of a virtuoso . but because some may think , i have spoken too much of a thing of small concern , i shall therefore say but one word or two more . that even upon the obscurest , and meanest of the creatures , the lord hath impress'd an indelible character , of his wisdom and skill . though we cannot well know , for what use and end , the oat-grain hath an awin , and why it is twisted , yet we must remember , that god , and nature , never made any thing in vain . do not undervalue it , because it is meanly let out ; for there is in it a pearl of great price ; christopherus sturmius a german , a great virtuoso , and famous mathematician , makes honourable mention of it , in his writings , which he hath taken from my a●s nova & magna , as he hath done many other curiosities and published them to the world , not as his own inventions , but as mine : which by the way , gives a notable check to my old adversaries , who with the bed●lls gown about their heads , endeavour'd to make the world , in their beggarly pamphlet believe , th●● all my philosophical experiments were untruths and lies . sed non est remedium adversus sycophantae mo●sum ; there is no cure or remedy against the bi●ng of slanderers . mr ▪ boyl did not think so as witness his experiments ●ouching flame and air. they are sold for six shillings . a short account of the late comets , and of some eclipsis . anno , an obscure comet appeared in the beginning of winter , seen in the forenight , nigh to the constellation of taurus . it did not continue long ; yet lilly that old astrologer made it very prodigious . a second , far more glorious , appeared in the beginning of december , . it raise before the sun several mornings , with a long ray , pointing towards the west . first then , it was cometa barbatus , the ray going before the star. it had a very swift motion towards the west , inclining upward , till it came the length , to be in opposition to the sun , on the . of december , where it appeared cometa crinitus , without a ray. being under a swift motion , it advanced more westerly and upward , and was seen clearly upon sunday night , december . with a long ray , pointing towards the east , which made it cometa caudatus , the train following the star , and setting after the sun. this made many believe , that there were two comets . it evanished a little below the rams-head , after it had continued from december . , to february . . a third was seen , the same year , in march , and continued till the . of april : a fourth was seen in the middle of april , , about . a clock at night . it continued but a short time . the fifth seen over all europe with admiration , appeared first clearly to us , december . . it continued till february . . the sixth comet , was seen thursday night , august . , in the north , about a clock at night , in the second foot of the great bear. it had a swift motion towards the west , declining from the north. it past over above the back of the lion , and under coma berenices , under arcturus , crossing bootes forefoot , towards the aequinoctial , and thence towards the beam of the ballance . anno , saterday night february , about a clock , a prodigious eclipse of the moon . the total darkness , continued an hour and a half , measured by the pendulum clock . the eclipse , was not only total , but central , that is to say , a straight line might have been drawn almost , from the centre of the moon , thorow the centre of the earth , to the centre of the sun. the moons face was red as blood , especially about the midle of the eclipse . compare it with ioel : . acts . , . isa. . . ezek. . , . mat. . . luk. . . anno , december first , all the seven planets met in that one sign of sagittarius , the archer . anno , friday october . a conjunction of saturn and iupiter in the . deg . of sagittarius . anno , april . mercury did eclipse the body of the sun. this year , a conjunction of saturn and iupiter in the sign leo , on the . of october , which is the fourth conjunction , since they entered the fiery trigon , which are sagittarius , leo , and taurus . anno , april . two suns seen in the firmament , in the fore-noon , in east-lothian . extraordinary foul-weather followed this parelia . anno , february . a total eclipse of the sun , so that the stars were seen . it is to this day called the dark saterday . anno , march , in the fore-noon , a total ecipse of the sun , so that the stars were seen likewise . it is commonly called the dark monday . simsines philadelphus , a devout man , and learned astrologue , writes in his book , which he published anno , and dedicated to frederick king of bohemia , that there never happened , any great change or alteration , in any state or kingdom , in europe ; but what hath been accompanied , with a conjunction of saturn and iupiter , under some trigon or other . and reckoning over all the ten principalities and dominions , which have been in britain , since the year of the world , he comes at last to the year , in which , saturn and iupiter , after they had returned into the fiery triplicity , being the seventh time from the creation , fell in conjunction in that fiery sign sagittary , in the month of december . here he takes occasion , to mention king iames , his succeeding to the crown of england that year , of whom by the way , take this distichon , or two verses . cura del , vasemque lab●r , sapientia secii , pax quoque , mulavit , regna quaterna polo . gods care , the ag●s wit , peace , prophets pairs , for kingdoms fou●● in heaven a kingdom gain● . and shews , that this , which he calls regnum scotorum , the dominion of the scots , and tenth principality , was received , by these two superior planets , in their greatest conjunction . note , that these conjunctions , are sometimes propitious , as this was . it was likewise favourable to the hollanders , who were treated with a free state anno . and concludes , with these remarkable words . et non jam expectanda est gravior aliqua mutatio in britannia , nisi continua consanguinearum successio ; siquidem periodi huic regno transierint . nam à primo rege bruto usque ad presentem annum elapsi sunt anni . that is , and now there is not any greater change to be expected in britain , but a continued succession of the nearest in blood ; for truly the periods to these dominions are gone , and past over . because from the first king brutus to this present year , there are past years . this brutus was the first king of the britains , who began his reign in the year of the world , under the aerial trigon , and conjunction of saturn and iupiter , in the sign gemini . for the better understanding , know that the twelve signs are divided into four triplicities , which are called by astrologues trigons . the first trigon , is called the fiery trigon , which contains , aries , leo , and sagittarius . the second is the earthy , which contains , taurus , virgo , and capricorn . the third is the a●rial , which contains , gemini , libra , and aquarius . the fourth is the watery , which contains , cancer , scorpius , and pisces . if it happen , that saturn , and iupiter be in conjunction this year in leo , there next conjunction , will happen , twenty years after , or truly , years , . days , and . hours after , in sagittarius . from sagittarius to aries ▪ from aries to leo , and so in round till . years , and . days passing , they make a transit into a new trigon , so that the revolution of one trigon consumes almost . year . my author speaking of that conjunction , which fell out anno . in aries , says , alicujus imperii , vel regni , revolutionem portendit . it betokens a change in some empire or kingdom in europe , which really came to pass after , as all know . a journal of the late great comet under the latitude of . deg . . m. . s. on the . of november , , it was first seen at plimmouth , in england , soon in the morning . upon the . of decem. being tuesday , it appeared first to us , in the constellation called antinous . this antinous , was of the country of bithynia , who for his vallant deeds , was canonized , and added to the number of the gods , and placed in heaven , in capricorn , in which sign the sun at that time was , deg . . m. . this comet had a ray , which went straight up from it , about . degrees in length . this night , at . a clock , it had . deg . of altitude , above the horizon . the ray was broader , and more spread out above , than below . in the head was a clear star , of a whitish colour . the middle of the ray covered the lesser star in the gorge of the eagle . the poets feign , that this was the bird , that flew up into heaven with ganymedes , whom iupiter loved so dearly ; for which good service , he placed the bird among the stars ▪ wednesday , decemb. ▪ at . a clock at night , the blazing-star , seemed to be higher , by . degrees almost , and more easterly . for this night , the middle of the ray eclipsed the bright star , in the neck of the eagle , which is the greater , and more towards the east ; but somewhat lower . the pinion of the lowest wing of the swan , did terminate the extremity of the train . on thursday morning following , about . a clock , the ray was seen above the horizon : at least much of it , not straight up , out sloping towards the north. at night , december . about . a clock , the star had about . degrees of altitude above the horizon . at which time , the ray had passed by , both the two forementioned stars in the neck of the eagle , it being far more easterly . it was not seen , till sunday at night , december . at which time , it was yet further up above the horizon , the middle of the train , covering the constellation , called the delphin . neptune the god of the sea , greatly desired , to match with amphitrite , who being modest , and shame-faced , hid her self . after long search , he sent the delphin , who found her out , for which good service , he placed this fish in the heaven . it was not seen till decemb. . at which time in the evening , it was past the aequator , and had about . degrees of north declination , and was in the . degree of aquarius , not far from the nose of pegasus . the night following , being saterday , decemb. . it was not seen . sunday decemb. . it was seen , at . a clock , with . degrees of altitude . the middle of the ray , did cover the right knee of pegasus . the end did terminate in the very zenith , between cassiopea , and perseus . after this the star was not seen , till ianuary . . this night the ray , past thorow the belly of pegasus . perseus did terminate the end of it . pegasus the winged horse , was bred of the blood of medusa , after that perseus had cut off her head. bellerophon made use of this horse , and having performed some valiant deeds here on earth , endeavoured to fly up to heaven on his back ; but being amazed by looking down to the earth far below him , he fell from his sadle . pegasus , notwithstanding continuing his journey , came at last into heaven , and there obtained a place among the constellations . monday ianuary . the comet was distant from and●omeda her head , about degrees , but somewhat more westerly . upon tuesday ianuary . the comet , was nearer to the head of andromeda , but somewhat lower . ianuary . being wednesday , the comet was within a degree and a hal● , of the head of andromeda , but a little lower , and more westerly . thursday ianuary , the comet was higher , than the head of andromeda , but more easterly . the ray passed thorow between the two bright stars , in the belt of andromeda . perseus did terminate the end of it . this night , the ray was . degrees long . friday ianuary . it was not seen . saterday ianuary . the head of the comet , was within one degree , of the star , which is in the lest shoulder of andromeda , but a little higher , and more easterly . the ray was . degrees extended . sunday ianuary , the comet was yet higher , by one degree , and more easterly , than the foresaid star. the bright star in the south foot of andromeda , did terminate the end of the ray. it was not seen , till friday ianuary , on which night , it was about mid-way between the bright star , in the belt of andromeda , and the point of the triangle , but somewhat higher to the said bright star. andromeda was the daughter of cepheus , and casstopea , and the wife of perseus , who , by the favour of minerva , was taken up into heaven , and placed among the constellations . saterday ianuary , the comet was somewhat higher , than it was the night foregoing . tuesday night ianuary , it had this position with the triangle , according to the first figure . thursday night ianuary , it had this position with the triangle , according to the second figure . thursday night ianuary , it was thus placed , according to the third figure , about one degree , and a half above the eastmost star in the b●se of the triangle . the ray was about . degrees in length . the end of it , was bounded with the eastside of medusa's head. the triangle was placed in heaven , in honour of the geometricians , among whom , the triangle , is of no small importance . others say , that it was placed there by mercury , that the head of the ram , might be the better knowen . saterday night ianuary , the comet , was in a right line , with the first star of aries , and the bright star in medusa's head. and in a right line , with the west-most star , in the base , of the triangle , and the pleiades . it was the matter of . degrees distant from the east-most star , in the base of the triangle , further up , and more easterly . perseus , the son of iupiter , and danae , kill'd the monster medusa , and cut off her head. her golden hairs were turned into serpents by minerva , for polluting her temple with neptune . whosoever looked on her after this , were turned into stones . perseus , falling into trouble of mind , for killing accidentally , his grand-father acrisius , was taken up into heaven , by his father iupiter , and placed there , with medusa's head in the one hand , and the sword in the other . wednesday february , the comet was scarce discernable , yet further up in the heavens , and more towards the east , than before . tuesday night , february . being the last time , it was seen , nothing appeared distinctly , save a small short ray. this night , it had . degrees of north latitude , from the ecliptick . it had . degrees of longitude , from the first point of aries . it was distant from medusa's head , . degrees . it was distant . degrees , from the west-most star , in the base of the triangle . it was . deg . . m. from the bright star in andromeda's foot . it was . degrees , from the first star in aries . it was . deg . . m. from the pleiades , or seven stars . it was in the . degree of taurus . from december , . until february , . it had advanced , the matter of . degrees , in the arch of a great circle , following the order of the . signs , from about the beginning of capricorn , to the . of taurus . this perhaps , may be lyable to the pharisaick censure , of some mathematical rabbi ; but let him first , be at as much pains , as i have been at in observing ; and next , let him make his observations , as accurate , and true as these are , without an observatory , and the help , of fit , and proper instruments . these are to give advertisement , to all ingenious persons , who have found out , any new inventions , or made any new observations , of things astronomical , of things in the sea , in the earth , above ground or under . in a word , whatever may be useful , for the promoting of natural knowledge , and learning , and profitable to others , let them be communicated to the author of this transaction , a true narration being made , he shall have them published , with accuracy , and satisfaction to himself . printed in the year , praefvlsêre dvo , res anno rara , plánetae , hei nobis miseris , ivngvntvr , in ore leonis . vvhen satvrn in the heav'ns , to iove comes near , to the reader . courteous reader , i shall not detain thee in the entry with a long preface , but give a short account of what is needful to be known , of the cause , occasion , and matter of the following treatise . after the publication of my last piece , about the weight and pressure of the air , i found it needful to treat of the pressure of the water , because of the near relation between the two : the operations , and effects of both depending almost upon the same principles and causes . and that there are many things , which cannot through●y be understood , of the pressure of the air , without the knowledge of the pressure of the water : therefore to make the first the more evident , i have spoken of the second : the effects and operations of hydrostatical experiments , being more conspicuous and sensible , then the effects and operations of the other . the occasion was some spare time i had now and then , for making some trials : part whereof are published here ; the rest being rather some productions of reason , attentively exercised on that subject ; which notwithstanding may be called experiments , though never actually tried , nor haply can be , because of some accidental impediments : yet supposing they were , i make it evident , that such and such phenomena would follow , whence many necessary conclusions are inferred . as for the subject matter , there are first , moe then thirty theorems in order to the pressure of fluid bodies , as air , water , and mercury , which in effect are nothing else , but so many conclusions rationally deduced from various and diverse effects of aerostatical , hydrostatical , and hydrargyrostatical experiments , which for the most part , i have tried my self . there are next twenty experiments briefly described , by their own distinct schematisms : their phenomena , according to the laws of the hydrostaticks are salved , and several new conclusions inferred . a proposal is likewise made of a more convenient engine for diving . here , several difficulties are proposed , and answered , and all the obvious phenomena of diving explicated . if the lead which sinks the ark , be judged too weighty , and big , which may render it not so tractable , and likewise hinder the ark from going so near to the ground , as is desirable , and in some measure stop the sight , ( which troubles are ( i suppose ) incident to the bell also ) it may be reduced to a far less weight , and quantity , and the overplus being made square and thin pieces , may line the mouth of the ark without , between p q and l m , according to the figure , or may be put to , or taken away at pleasure . the bell may have likewise in stead of this troublesome foot-board , a weighty ring of lead , or two , to go round about the orifice without , in form of a girth , or belt , which may slip off and on at pleasure , and will as conveniently sink it , as if it had a weight appended : the foot-board then may be of any form , quantity , or weight you please . there are thirdly some miscellany observations , the design of which is only philosophical . some of them are experiments made with the air-pump , which i have adventured to insert here , even though the noble mr. boyl hath given an account of many . but because the engine was offered to me by the laird of salton , a gentleman of a choise spirit , i could not , but in obedience to his commands make use of it , and shew him the product . there are also two or three observations in the close , as that of the primum vivens in animals : of the aliment , and growth of plants : and of the motion of the aliment in trees . to all which is added a short history of coal , which i hope will be acceptable to some ; this so needful a subject , never being treated of before by any . in it , mention is made of things common to coal in general , as dipps , risings , and streeks . next , of gaes , or dykes , which prove so troublesome sometimes to the working of coal . thirdly , of damps , and wild-fire . next , a method is taught for trying of grounds , where never any coal was discovered before . and lastly , the manner how levels , or conduits under-ground , ought to be carried on , for draining the coal , and freeing it of water . when this book was first committed to the press , i sent an intimation thereof to some of my friends , for their encouragment to it , a practice now common , and commendable , which hath not wanted a considerable success , as witness the respect of many worthy persons , to whom i am oblidged . but there is a generation , that rather , than they will encourage any new invention , set themselves by all means to detract from it , and the authors of it : so grieved are they , that ought of this kind should fall into the hands of any , but their own . and therefore , if the author shall give but the title of new to his invention , though never so deservedly , they fly presently in his throat , like so many wild catts , studying either to ridicule his work altogether ▪ a trade that usually , the person of weakest abilities , and most empty heads , are better at , than learned men , like those schollars , who being nimble in putting tricks , and impostures upon their condisciples , were dolts , as to their lesson , or else fall upon it with such snarling , and carping , as discover , neither ingenuity , nor ingeniousness , but a sore sickness , called envy . in the intimation , i affirmed , that the doctrine concerning the weight , and pressure of the water was new. this one word , like a spark of fire falling accidentally among powder , hath been the occasion of so much debate . their ground is , because they look upon the hydrostaticks , as a science long ago perfected , seing archimedes years ago hath demonstrat the water to have a pressure , and some others since , as stevinus . they affirm likewise , that all the theorems , and experiments , that are here , are either deduceable from archimedes , and stevinus , or are the same with theirs . if these gentlemen had suspended their judgment , till this book had been published , i suspect they would not have spoken so confidently . for archimedes his propositions , they are but few , and proven ( as mr boyl saith ) by no very easie demonstrations , which have more of geometrical subtility , than usefulness in them . but these , which are here proposed , are not only useful , but evidently evicted by reason , and sensible experiments , even to the meanest capacities . and though some of mine , may ( perhaps ) co-incide with some of his , which to me is but accidental , yet our way of procedour is toto coelo different . his way is more speculative : this is more practical . his demonstrations are geometrical : these are physical . his propositions are but for the use of a few : these are for the use of all . his are not illustrated , and confirmed by hydrostatical experiments : these are . stevinus a late writer keeps that same method . yet i judge it easie to let see , even in the entry , how little cogent some of his demonstrations are , without derogating from such a learned man. he hath indeed some pragmatical examples ( as he calls them ) for illustrating some of his geometrical propositions , anent the pressure of the water ; but i leave them to be considered by the judicious and understanding . again , in this method , i am yet as much different from others , who have written lately , as from these i have been speaking of . for , i not only treat of the pressure of the water , but takes in with it , the pressure of the air joyntly ; since to explicat sufficiently the phenomena of the hydrostaticks , without it , it is impossible . and yet furder , i not only counterpoise air with water , but air with mercury , and water with mercury ▪ by which means several mysteries , and secrets in this art , are discovered . there are several inventions found out of late in the hydrostaticks , whose ●●ents and effects , cannot be clearly deduced from the grounds of archimedes , and stevinus , who had not that clear discovery ( for ought we know ) of the pressure of the air , that some now have , without which , these effects can never be sufficiently explained . and who doubts , but others afterwards , may make farder discoveries , and profit the world yet more , with their inventions , then any have yet done . is then the hydrostaticks , a science long ago perfected ? to this pedantick conceit , i must again oppose the judgment of mr. boyl , who saith moreover , that the usefulness of this part of philosophy hath been scarce known any farder than by name , even to the generality of learned men . but let us suppose that the notion of the pressure of the water , is of an old date , even as old as the flood ( for noah surely knew , that the pressure of the water , would sustain the ark ) and ( giving , but not granting ) that archimedes years ago hath written all the principles of the hydrostaticks , doth this hinder any man now , from deducing new conclusions from these old principles ? but there is here , no such thing for neither in this , nor in my last piece , are my adversaries able to trace me . 't is like the purposes would have been so much the better , if i had followed other mens foot steps : and it is like they might have been so much the worse . i doubt not , but i have lighted upon other mens thoughts in some things : and others writting on this same subject , who perhaps are my antipodes , may fall upon mine . my antagonists affirm , they are able to deduce all my theorems , and the events of all my experiments from the grounds of archimedes and stevinus . if they take not their word again , i hope they will do it ; for now i put them to it . and though they should , ( which i am not affraid they shall do in haste ) yet they must prove next , that these theorems and conclusions , so deduced , are not new , which all their logick will not prove . but what if we do more , ( say they ) even overthrow many of all your aerostatical and hydrostatical experiments , in this , and in your last pe●ce ? i give you liberty , and for your hire , a guiny for each theorem , or experiment , you are able to ransack , in either of the two books , though they come near to an hundred . but , ye must oblige your selves ( my maste●s ) to do it with reason , laying aside your sophistry and ●anina eloquentia . and this i offer , reader , that i may reduce them , to a better humour , and encourage them to leave off flyting , and only use reason . neither must they be like the wasp , that only lights upon the sore place . but if they love to kindle any more fire , they will find me proof against it . if it burn them , it shall not heat me . nevertheless , if they love to juik under deck , like green-horns , having no courage in themselves , or confidence in their cause , they must excuse me , if at last , i write their names upon a ticket , and bring them above deck . this is all i have to say , at present ( reader ) and i bid thee farewell . errata . pag. . lin . . for weight read bensil . pag. . lin . . for eh , read fh . pag. ● . lin . . for . read . pag. . lin . . read promoting . pag. . lin . . read reflection . ibid. lin . . read elaborarint . pag. . lin . . read & magna . note , that in placing the figures , the , that should have the fourth place in the third plate , hath the first place in the fourth . contents of the experiments . the first , second , and third experiment , touching the rising and falling down of water in tubs of different sizes . pag. . . . the fourth is a hydrostatical experiment , shewing the reason why the mercurial cylinder rises , and falls , in the torricellian experiment , as it is carried up , or down thorow the air. pag. . the fifth , shewing the reason , why the mercurial cylinder rises and falls in the baroscope , as the pipe is reclined and erected . p. the sixth , touching the suspension of liquors in pipes , either closs or open above , not only of water by water , but of water by air. pag. , &c. the seventh , touching the cause of the suspension , and keeping up of water in weather-glasses . pag. . the eighth , touching the reason , why a stone weighs less in water than in air. pag. . &c. the ninth , touching the reason , why under a water foot deep , the hight of the mercury in the baroscope , is inches . pag. . &c. the tenth , touching the reason , why a man gripping with his fingers the torricellian tub , seems to find the weight of the liquor within , and yet finds it not . pag. . &c. the eleventh , touching the counterpoising of mercury in glass-pipes under-water , by the help of a ballance above , adduced to prove that a heavy body weighs as much in water , as in air. pag. . the difficulty answered , pag. . &c. the twelfth , touching the reason , why a cylinder of brass , may be suspended by a surface of water , before it touch the bottom , that 's foot deep . pag. . &c. the thirteenth is , touching two plain heavy bodies suspended under a water foot deep . pag. doctor mores argument against the pressure of the air , answered . pag. the fourteenth , touching the counterpoising of mercury with water : of mercury with air and water ; whence some notable phenomena appear . pag. . &c. the fifteenth , touching an experiment tried in a water foot deep . pag. . &c. the sixteenth , touching the reason , why the different wideness of tubs , makes no alteration in the hight of the liquors suspended in them . pag. . the seventeenth , a notable trial for proving the pressure of the water . pag. . &c. mr. boyls experiment insufficient . pag. . the eighteenth , touching the diving-ark . pag. . &c. the nineteenth , touching a siphon made to work under water with mercury , by the pressure thereof , as a siphon operats with water , by the pressure of the air. p. . the last is for demonstrating the precise and just weight of any pillar of air , water , or mercury . p. . &c. contents of the miscellany observations . observation . anent the killing of animals in coal sinks , by the power of damps and ill air. pag. . observ. . touching the position of iupiter , with the stars of gemini , novemb. . . p. . observ. . for knowing the motion of the sun , or moon , in seconds of time . ibid. observ. . touching an experiment made on the top of cheviot . p. . observ. . touching the oval-figure of the sun , at his setting . p. . observ. . touching a considerable thunder , with great lightnings , in east-lothian , in iuly . p. . observ. . a method for finding out the true south and north points . p. . observ. . touching the reason , why a dead body of a man , or beast , riseth from the ground of a water , after it hath lien there three or four dayes . p. . observ. . is a second experiment made in a coal-sink , for knowing the power of damps and ill-air . p. . observ. . an account of experiments tried with the air-pump . p. . observ. . an experiment made , for knowing the reason , why a round heavy body , as a bullet of iron , falls not off a plain body , under motion , but lies dead . p. . observ. . shewing the reason why a stone demitted from the top of a ships-mast under sail , falls directly upon the place it hang over . p. . observ. . touching the hight of the mercury in the baroscope , observed by d. beal . p. . observ. . touching the variation of the magnetick needle here . p. . observ. . touching the elevation of the pole here . p. . observ. . a second method for finding the meridian . p. . observ. . touching a considerable showre of hail , with thunder , and rain . ibid. observ. . touching a curious experiment made lately in germany , for shewing the wonderful force of the air. p. . observ. . touching some proposals of new engines for war. p. . observ. . touching a sad trial one mr. campbel suffered in his family for many dayes from the devil . p. . observ. . touching a large horn cut off a womans head lately . p. . observ. . touching the primum vivens in animals . ibid. observ . touching the aliment and growth of plants p. . and touching the motion of the aliment in trees . p. . observ. . touching a history of coal . p. . in auctorem & opus encomiasticon . aether is expansi , vitrei maris antitalanton , peroledos , elasin , fluidarum ritè videntes , ingenio patefacta tuo , magnalia rerum , laudarûnt alacres galli , belgaeque sagaces . aggreder is nunc arte novâ , trutinare profundi corpora , submersas quondam producere gazas , tollere demersis ingentia pondera cupis . gas fracidum in cryptis ortum fossoribus atrox , submisso in fundos aurae renovante flabello , propulsare doces , lithanthracumque cavernae quê is foveantur aquis , quo tendant , unde oriantur , ordine quò circum saxorum strata recumbant . quòd benè coepisti naturae cuncta foventis munera solerti perge illustrare mathesi . georgius hepburnus , m. d. à monachagro . to the reader . reader , that thou mayest know , by one word more , how useful this part of philosophy is , and how far from being a science long ago perfected , take but this following proposal , lately , since my book came to a close , communicated to me by a friend , which , by his ●llow●nce , i have published , reserving the answer to himself , the author thereof . brother , by what you have published in your ars nova & magna , and this book , i have been led to this invention , to beget within the bowels of the sea , a power , or force , which with great safety , and ease , shall bring up the greatest weight , that can be sunk therein : ad data quae cunque pondera demersa , in maris visceribus potentiam producere , quae modo securo , & facili , è fundo cujusvis altitudin's ad summum , ipsa evehat . i drew a letter one night , sh●wing the way how this might be done , which i communicated to you , that it might have been printed with your book : but after second thoughts , i judged it more meet to keep it up for a time , and that it should be set forth by way of proposal only at the first , by your brother , mr. iohn sinclar . o miston , may . . this new invention , though hydrostatical , is tru●y mechanical , there being here a ●ondus and a potentia , whose operations depends upon mechanical principles . but in several respects it is far more admirable , than the most part of the mechanical engines , which are look'd upon as stupendious . many things , almost incredible , are reported of archimedes , which he admirably brought about , by his mechanical powers ; but i am confident , that by this invention , as great a weight may be lifted , if not greater , as the power of any mechanical faculty can be able to move . i know , the greatest conceivable weight , may be demonstrat , to be moved by the least conceivable power , as the earth , by the force of a mans hand . but how is it possible to contrive artificially , an engine for that purpose , which will do that by art , which the demonstration makes evident by reason ? it was thought a great enterprize , when pope sixtus the fifth , transported an obelisk , which had been long since dedicated to the memory of iulius cesar , from the left side of the vatican , to a more eminent place , foot distant ; but to raise a ship of tun intirely , nay , a weight times greater , is surely a far greater enterprize . this invention is so much the more admirable , that not only by it , any supposed weight may be lifted , but from any deepness . though this ( perhaps ) cannot be done mechanically , because of some physical , or moral impediment , yet according to the laws of the hydrostaticks it can be demonstrat , and made evident by reason . and if this be , then surely , when the weight is determinat , as the burdens of all ships are , and the deepness known to be within so many fathoms , this invention cannot but be successful . though the strength of mechanical inventions , may be multiplied , beyond the bounds of our imagination , whereby the greatest weight , may be moved , by the least power ; yet the wisdom of god , hath thought it fit , so to confine that knowledge , that it cannot teach , how both of them , can move with the same quickness and speed . for , if that were , the very works of nature might be overturned . therefore , it is observable , that when a great weight is moved by a small power , the motion of the one , is as much slower than the motion of the other , as the weight of the one , exceeds the force of the other . if it were possible mechanically to move the earth with the force of a mans hand , the motion thereof would be as much slower , than the motion of the hand , as the weight of the one , exceeds the force of the other , which is a great disadvantage . and as the weight and power do thus differ , as to swiftness , and slowness in motion , so also , as to space . for , by how much the power is in it self less , than the weight , by so much will the bounds or space , the weight moves thorow , be less than the space , the power goes thorow . if it were possible ( keeping the same instance ) to move the earth with a mans hand , the space thorow which it passeth , would differ as much from the space the hand goes thorow , as the one exceeds the other ; which is another disadvantage . it may be thought , that if this invention depend upon mechanical principles , it may be obnoxious to these abatements . i answer , though there be in it a pondus , and a potentia , a weight , and a power , this moving the other , yet it will evidently appear from experience , that the motion of the one , is as swift as the motion of the other , and that the one moves as much space and bounds in the same time , as the other , which is a great advantage . in this , it excells all the mechanical powers , and faculties , that have ever yet been invented and practised . if any think , that such a device cannot be effectuat , without a considerable expence . i answer , the expence is so small , that i am ashamed to mention it . the method and manner of doing this , is most easie likewise . neither ought this to be a ground , why any man should contemn it ; since the most useful inventions ordinarily are performed with the greatest facility . as it commends this part of philosophy to all ingenious spirits , as most pleasant , and most profitable , so it gives a check to the ignorant , who look upon it as a science long ago perfected . in praise of the author , and his work . . whilst infant-art no further did pretend then to flat notions , and a bare desi●e ; what by small toyl we now do comprehend , our predecessors only did admire . . now fruitful reason , arm'd with powerful art , uncovers nature to each knowing eye : our author to the world doth here impart what was before esteem'd a mystery . . the various motions of that element , whose liquid form gives birth to much debate ; by demonstration he doth represent , unfolding th'intrigues of that subtil state . . the waters course , and sourse , from whence they flow , by him to th'sense so clearly are display'd ▪ their current weight , and measure now we know , 't is no more secret , but an open trade . w. c. hydrostatical theorems , containing some useful principles in order to that excellent doctrine , anent the wonderful weight , force , and pressure of the water in its own element . theorem i. in all fluids , besides the first and visible horizontal surface , there are many moe imaginary , yet real . figure . for the better understanding the following experiments , it is needful to premit the subsequent theorems ; the first whereof is , that in all fluid bodies , such as air , water , and mercury , or any other liquid , there is besides the first and visible surface , innumerable moe imaginary , under that first , yet real , as may be seen from the following schematism , which represents a vessel full of water , where besides the first surface abcd , there is a second efgh , and a third iklm , and so downward , till you come to the bottom . this holds true , not only in water , but in air also , or in any other fluid body whatsoever . i call the under-surfaces imaginary , not because they are not real ; for true and real effects are performed by them ; but because they are not actually distinguished amongst themselves , but only by the intellect . theorem ii. in all fluids , as it is needful to conceive horizontal plains , so it is needful to conceive perpendicular pillars , cutting these plains at right angles . figure . this proposition is likewise needful for understanding the following doctrine , anent the pressure of the water : for in it , as in all fluids , though there be not columes or pillars actually divided , reaching from the top to the bottom , yet there are innumerable imaginary , which do as really produce effects by their pressure , as if they were actually distinguished . these imaginary pillars are represented in the first schematism , one whereof is aeinopq , the other bfkrt , and so forth . theorem iii. there is a twofold ballance , one natural , another artificial . by the artificial ballance , i understand that which the mechanicks call libra , which merchants commonly use . by the natural ballance ( which for distinctions cause i so nominat ) i mean , v. g. a siphon , or crooked pipe , wherein water naturally ascends or descends , as high or low in the one leg , as in the other , still keeping an evenness , or likeness of weight . theorem iv. fluid bodies counterpoise one another in the ballance of nature , according to their altitude only . this theorem will appear afterwards most evident , while we pass through the several experiments ; and it is of special use for explicating sundry difficulties that commonly occur in the hydrostaticks . the meaning of it is shortly this : while two cylinders of water are in the opposite scales of the natural ballance , they do not counter poise one another according to their thickness : for though the one pillar of water be ten times thicker , then the other , and consequently heavier , yet is it not able to press up the other , that 's more slender , and so lighter , beyond its own hight : and therefore they weigh only according to their altitudes . theorem v. in all fluids there is a pressure . figure . this is true not only of the elements of air , and water , while they are out of their own place ( as they speak ) but while they are in it . for air and water , being naturally indued with weight , the second foot cannot be under the first , unless it sustain it : if this be , it must necessarily be prest with its burden . so this water being naturally a heavy body , the foot i cannot be under e , unless it sustain it , and be prest with the burden of it ; the foot n , being burdened with them both . from this pressure , which is in air , ariseth a certain sort of force , and power , which may be called bensil , by vertue whereof , a little quantity of air , can expand and spread out it self , to a very large quantity , and may by extrinsick force be reduced to that small quantity again . though this expansive faculty be evident in air , yet it is scarcely discernable in water , unless it be in very deep parts , near the bottom , where the pressure is great . this pressure is not of the same degree in all the parts , but is increased and augmented , according to the deepness of the air and water ▪ for the air upon the tops of mountains , and high places , is thought to be of a less pressure , then in valleys : and water is of a less pressure , ten or twelve foot from the top , then twenty or thirty . so is the water n , under a far less pressure , then the water , p or q. theorem vi. the pressure of fluids is on every side . figure . the meaning is , that air and water presseth not only downward , but upward , not to the right hand only , but to the left also , and every way . so the foot of water k , not only presseth down the foot r , but presseth up the foot f , yea presseth the foot i , and the foot l , with the same weight . and the first imaginary surface , is as much prest up , by the water iklm , as it is prest down by the water efgh . upon this account it is , that when a sphere , or glob is suspended in the midle of water , or air , all the points of their surfaces are uniformly prest . after this manner , are our bodies prest with the invironing air , and the man that dives , with the ambient and invironing water . theorem vii . all the parts of a fluid in the same horizontal line , are equally prest . figure i. the meaning is , that the foot i , is no more prest , then the foot k : neither is the foot l , more burdened , then the foot m. the reason is , because each of these feet , sustains the same weight : for efgh are all of them , of the same burden : therefore all the parts of a fluid in the same horizontal surface , are prest most equally . this holds true in air , and mercury , or in any other liquid also . theorem viii . the pressure of fluids seem to be according to arithmetical progression . figure i. the meaning is , that if the first foot of water , have one degree of pressure in it , the second must have only two , and the third must have only three , and so forth , which appears from the schematism : for the first foot e , having one degree of weight , and the second foot i , having of its self as much , and sustaining e , it must have two degrees , and no more . so the foot n , sustaining two degrees of pressure from i and e , must have the weight only of three degrees , o of four , p of five . it 's evident also from experience , for while by the pressure of water , mercury is suspended in a glass tub , we find , that as the first fourteen inches of water , sustains one inch of mercury , so the second fourteen inches sustains but two , and the third , but three . but if the pressure were according to geometrical progression , the third foot of water ought to sustain four inches of mercury , the fourth , eight ; the fifth , sixteen , &c. which is contrary to experience . theorem ix . in all fluids there is a twofold weight , one sensible , the other insensible . the first is common to all heavy bodies , which we find in water , while we lift a vessel full of it from the ground . the insensible weight of water , and air , or of any other fluid , can scarcely be discerned by the senses , though it be as real , as the former , because the pressure is uniform . by vertue of the second , bodies naturally lighter than water , are driven from the bottom to the top , as cork . so , a man falling into a deep water , goes presently to the bottom , and instantly comes up again . here is a natural effect , which cannot want a natural cause ; and this can be nothing else , but the pressure of the water , by vertue whereof he comes up , and yet he finds nothing driving him up , or pulling him up . therefore , there is in all fluid bodies , an insensible weight , as there is one sensible ; seing the man that ( perhaps ) weighs seventeen stone , is driven up fifteen or sixteen fathom by it . and it must be very considerable , and exceed the weight of the man , seing it is able to overcome such a weight . so are vapours and smoke driven upward by the insensible weight of the air , and by that same weight , do the clouds swim above us . theorem x. the insensible weight of fluids , is only found by sense , when the pressure is not uniform . for understanding of this proposition , i must suppose somethings that are possible , but not practicable . put the case then , while a man opens his hand , the air below were removed , he would scarce be able to sustain the weight of the air , that rests upon the palm above : or if the air above were annihilated , he would not be able to bear down the weight that presseth upward . or , while a diver is in the bottom of the sea , if it were possible to free any one part of his body from the pressure of the water , suppose his right arm , i doubt not , but the blood would spring out in abundance from his finger-ends : for the arm being free , and the other parts extreamly prest , the blood of necessity must be driven from the shoulder downward , with force , which cannot be without considerable pain . it is evident also , from the application of the cuppin-glass , which being duely applied to a mans skin , causeth the air to press unequally , the parts without , being more prest than the parts within , in which case the unequal pressure causeth the pain , and so is found by sense . theorem xi . a cylinder of water , or of any other fluid body , loseth of its weight , according to its reclination from a perpendicular position , towards an horizontal or levell scituation . for understanding of this , consider that while a pipe full of water stands perpendicular , the lowest foot sustains the whole weight of the water above it : but no sooner you begin to recline the pipe from that position , but assoon the pressure upon the lowest foot grows less ; so that if the lowest foot , in a perpendicular position , sustained the burden of ten feet , it cannot sustain above five or six , when it is half reclined . a certain evidence whereof is this , the more a cylinder of water is reclined towards the horizon , or level , it takes the shorter cylinder of water to counterpoise it , as is evident in siphons . for , though the one leg , be sixteen inches long , and the other but six ; yet a cylinder of water six inches long , will counterpoise a cylinder of sixteen . but this cannot be , unless an alteration be made in the pressure . for , how is it possible , that a cylinder of water can sometimes be in aequilibrio with a lesser , and sometimes with a greater weight , unless the weight , and pressure of it , be sometimes more , and sometimes less ? when i say a cylinder of water loseth of its weight by reclination , it is to be understood only of the insensible weight : for the sensible weight is unchangeable , seing it is alwayes a pillar of so many inches , or feet . now the true reason , why the pressure upon the lowest foot grows less , is this ; the more the pipe is reclined , the more weight of the cylinder rests upon the sides of the pipe within ; by which means , the lowest foot is eased of the burthen , and is altogether eased , when once the pipe lyes horizontal . theorem xii . all motion in fluids , is from the unequal pressure of the horizontal surface . figure . for understanding this , i must distinguish a twofold motion in fluids ; one common , another proper , by vertue of the first , they incline , as all other heavy bodies , to be at the center of the earth . it is evident in the motion of rivers , which descend from the higher places to the valleys , even by vertue of that tendency they have to be at the center . by vertue of the second , they incline to move every way ; not only downward , but upward , hither and thither . this sort of motion is peculiar , and proper only to fluids ; and it is that which is spoken of in this theorem . i say then , that all motion in fluids , is from the unequal pressure of the horizontal surface . for put the case a , were more prest then b , e. g. with a stone , then surely as the part a descends , the other part b will ascend , and so will c and d rise higher too . suppose next , the part a were fred of the pressure of the air , then surely in the same instant of time , would the part a ascend , and the parts bcd descend . as this proposition is true in order to the first and visible surface abcd , so it is true in order to the imaginary surface iklm ; for put the case the space i , were filled with a body naturally heavier then water , as lead or stone , then behoved that part of the surface to yeeld , it being more prest , then the part of the same surface k. or if the space k were filled with a body naturally lighter then water , as cork , then ought the water r to ascend , it being less prest , then the water n or s. theorem xiii . a body naturally heavier then water , descends ; and a body naturally lighter , ascends . figure . for understanding of this , let us suppose the quadrat space e , to be filled with a piece of lead or iron . i say then it must go down to i ; and the reason is , because the quadrat foot of water i , is more pressed then the quadrat foot of water k. to illustrat this , let us suppose that each quadrat foot of this water weighs a pound , and that the heavy body existing in e , weighs two pound . if this be , the foot of water i , must yeeld , seeing it is more prest then k : upon the same account must the water n yeeld , and give way to the stone , seeing it is more prest then r. for according to the twelfth theorem , there cannot be unequal pressure upon a surface , unless motion follow . for understanding the second part , let us suppose the space r , to be filled with a piece of cork , that is specifically or naturally lighter then water . i say then , it must ascend to the top b ; and the reason is , because the quadrat foot of water k , is more prest upward , then the quadrat foot of water i , or l is : but this cannot be in fluid bodies , unless motion follow thereupon . i say , it is more prest up , because r being lighter then n , or s , it must press with greater force upon k , then s can do upon l , or n upon i. it is still to be remembred , that fluids presseth with as much strength upward , as downward , according to the sixth theorem ; and that an horizontal surface doth as really suffer unequal pressure from below , as from above . theorem xiv . bodies naturally lighter then water , swim upon the surface and top . figure . the reason of this proposition must be taken from the nature of an equipondium , or equal weight . for without doubt , there is a counter-ballance between the pressure of the water , and the weight of the body that swims . to make this probable , let us suppose there were a piece of timber in form of a cube , six inches thick every way , without weight . in this case , the under-surface of that four-squar'd body , being applied to the surface of the water a , would ly closs upon it , as one plain table lyes upon the face of another , without any pressure : and it being void of weight , the part of the surface a , would be no more burdened , then the next part b adjacent , whence no motion would follow . here is no equipondium , or counter-ballance . secondly , let us suppose the said body to acquire two ounces of weight , then it follows , that it must subside , and sink two inches below the surface abcd ; and that so far , till it come by vertue of its new acquired weight , to a counter-ballance with the pressure of the water . which pressure is nothing else , but as much force or weight , as is equivalent to the weight of water , that is thrust out of its own place , by the subsiding and sinking of that body , two inches . thirdly , let us suppose the same body to acquire other two ounces of weight , then must it subside other two inches . lastly , let us suppose that it acquires six ounces of weight , then it follows that the whole body sinks , so far , i mean , till its upmost surface be in an horizontal line with the surface of the water abcd. here it swims also , because the weight of it becomes just the weight of so much water , as it hath put out of its own place . i say , it must swim , because if the water i , was able to sustain the water e , which is put from its own place , surely it must be able to sustain that body also , that did thrust it from its own place , seing both are of the same weight , namely six ounces . in this case , the body immerged , and the water wherein it is drowned , become of the same weight specifically , seing bulk for bulk is of the same weight . to make this body specifically , or naturally heavier then water , and consequently to sink to the bottom , nothing is required , but to suppose that it acquires one ounce more of weight ; which done , it presently goes down , i , being more burdened then k. note by the way , a twofold weight in heavy bodies , one individual , the other specifick , and that two bodies agreeing in individual weight , may differ in specifick weight . so a pound of lead , and a pound of cork , agree individually , because they are both . ounces : but they differ specifically , because the one is naturally heavier then the other . theorem xv. no body that flots above water , even though its upper surface be level with the surface of the water , can ever be made to swim between the top and the bottom . figure . for clearing this proposition , let us suppose f to be a four-square piece of timber , of the same specifick and natural weight with water , and consequently its upper surface to be level with the surface of the water abcd. i say then , if it be prest down to r , it shall arise thence , and never rest till it be where it was , namely in f. the reason seems to be this , because the four-squar'd body of water r , is really heavier , then the four-squar'd piece of timber f. if this be true , it follows of necessity , that it must ascend : for if the timber existing in r , be lighter then the water r , the water t must be less prest , then the water o , or the water v ; whence ( according to the twelfth theorem ) motion must follow . again , if the timber r , existing in the water r , be lighter then the same water is , then must the water k , be more prest up then the water i , or l ; whence yet , according to the same theorem , motion must follow . if it be said , that the timber f , is of the same weight with the water r , because , it being equal in weight with the water f , which it hath thrust out of its own place , it must also be equal in weight to the water r , seeing f and r being of the same dimensions , are of the same weight . there is no way to answer this difficulty , unless i say the four-squar'd body of water r , is really and truly heavier then the four-squar'd body of water f. the reason seems to be , because the water r , is under a greater pressure , then the water f ; and by vertue of this greater pressure , there are really moe parts of water in it , then in f ; therefore it must be heavier . even as there are far moe parts of air , in one cubick foot near the earth , then in six or seven near the atmosphere . hence it is , that a pint of water taken from the bottom of the sea , fourty fathom deep , will be heavier , i mean in a ballance , then a pint taken from the surface . take notice , that when the vessel is once full at the bottom , the orifice must be closely stopped , till it come to the top : otherwise the parts that are compressed at the bottom , namely by the weight of the superiour parts , relaxes themselves , before they come to the top . theorem xvi . it is not impossible for a body to be suspended between the surface and the bottom . figure . for understanding this , suppose f to be a four-square piece of timber , which though it will not rest but at the surface , abcd , yet may be made to go down of its own accord , and rest at t , namely , by making it so much heavier , as the water t is heavier then the water f. to know this difference , which is not very practicable ; the cube of water t , must be brought from its own place , under the same degree of pressure it hath , and put into the scale of a ballance , and weighed with the cube of water f , put into the other scale . now if the water t , be half an ounce heavier , then the water f , then to make the timber f hing in t , it must be made half an ounce heavier . there seems to be reason for it also ; for if a cube of timber resting in the space t , be just the weight of the water t , the imaginary surface otv , is no more prest , then if t were water , and so it cannot go downward : neither can it go upward , seing the under part of the water r , is no more prest up by the timber t , then if the space t were filled with water . if it be said , according to this reasoning , a stone may be suspended in a deep water , between the top and the bottom , which is absurd . i answer , such a thing may happen in a very deep water : for put the case a cube of lead twelve inches every way , were to go down twelve thousand fathom , it is probable , it would be suspended before it came to the ground . for coming to an imaginary surface far down , where the pressure is great , a cube of water twelve inches thick there , may be as heavy ( even specifically ) as the cube of lead is , though the lead be ten times heavier specifically , then any foot of vvater at the top . if water suffer compression of parts , by the superiour burden ; it is more then probable , that the second foot of water burdened with the first , hath moe parts in it , then are in the first , and the third moe , then in the second , and so forth ; and consequently , that the second is heavier , then the first , and the third heavier , then the second . now , if this be , why may not that foot of water , that hath sixty thousand foot above it , by vertue of this burden , be so comprest , that in it may be as many parts , as may counter-ballance a cube of lead twelve inches every way ? if then , that imaginary surface , that is sixty thousand foot deep , be able to sustain the said foot of vvater , which perhaps weighs twenty pound , why may it not likewise sustain the lead , that is both of the same dimensions with it , and weight ? hence it is , that the clouds do swim in the air , by vertue of a counter-ballance : and we see , which confirms this doctrine , that the thinnest and lightest are alwayes farthest up ; and the thickest and blackest , are alwayes farthest down . theorem xvii . the lower the parts of a fluid are , they are the heavier , though all of them be of equal quantity and dimensions . figure . this follows from the former , which may appear a paradox , yet it seems to be true : for though the water q at the bottom , be of the same dimensions with the water e at the top , yet it is really heavier , which happens ( as i said ) from the superiour pressure . it is clear also from this , namely the cube of timber e , which swims upon the surface , being thrust down to q , comes up to the top again , which could not be , unless the water q , were heavier then the water e. i suppose the water e , and the timber e , to be exactly of the same sp●cifick weight , and consequently the surface of the timber , to ly horizontal with bcd . now the reason , why the timber ascends from q to e , is no other then this , namely that the one water is heavier then the other ; for the under part of the water p , being more prest up with the timber existing in q , then with the water q it self , it must yeeld and give way to the ascent : for if the cube of timber existing in q , were as heavy as the water q it self , it would no more press upon p , or endeavour to be up , then the water q does . theorem xviii . a heavy body weighs less in water , then in air. figure . this is easily proven from experience ; for after you have weighed a stone in the air , and finds it two pound , and an half , take it , and suspend it by a threed knit to the scale of a ballance ; and let it down into the water , and you shall find it half a pound lighter . the question then is , why doth it lose half a pound of its weight ? i answer , the stone becomes half a pound lighter , because the surface of water on which it rests , sustains half a pound of it : for put the case a stone were resting in r , that weighed two pound and an half in the air , it behoved to weigh but two pound in this water ; because the water t sustains half a pound of it . for if this water t be able to sustain the water r , that weighs half a pound , it must be also able to sustain half a pound of the stone , seing half a pound of stone is no heavier , then half a pound of water . note , that when a heavy body is weighed in water , it becomes so much lighter exactly , as is the weight of the water it thrusts out of its own place . theorem xix . a heavy body weighs less nigh the bottom of the water , then nigh the top thereof . figure . for clearing this proposition , i must suppose from the . theorem , that the lower the parts of water be , they are the heavier , though all of them be of equal dimensions . if then the lowest foot q be heavier , that is , have moe parts in it , then the foot n , it of necessity follows , that a stone suspended in q , must be lighter then while it is suspended in n or i. because , if a stone be lighter in water then in air , as is said , even by as much , as is the weight of the bulk of water , that the bulk of the stone expells , then surely it must be lighter in the one , then in the other place ; because suspended in q , it expells moe parts of water , then while it is suspended in n or i. for example , let us suppose the water n , to weigh eight ounces , and the water q to weigh nine , then must the stone suspended in q , weigh less by an ounce , then suspended in n , seeing as much is deduced from the weight of the stone , as is the weight of the water it expells : but so it is , that it thrusts nine ounces of water out of its own place in q , and but eight in n or i ; therefore it must be one ounce lighter in the one place , then in the other . this may be tried , with a nice , and accurat ballance , which will bring us to the knowledge of this , namely how much the foot of water q is heavier , then the water n or o. theorem xx. one part of a fluid , cannot be under compression , unless all the parts next adjacent , be under the same degree of pressure . figure . this proposition may be proven by many instances : for when the air of a wind-gun , is reduced to less quantity by the rammer , all the parts are most exactly of the same bensil . so is it in a bladder full of wind . it 's true , not only in order to this artificial pressure , but in order to the natural pressure , and bensil of the air likewise . for the air within a parlour , hath all its parts , under the same degree of natural compression : so is it with the parts of the air , that are without , and immediatly under the weight of the atmosphere . it s evident also in the parts of water : for the foot of water r , cannot be under pressure , unless the water s , and n , be under the same degree of it . though this be true of fluids , while all the parts lye in the same horizontal surface , yet to speak strictly , it will not hold true of the parts scituated under divers surfaces ; for without question , the foot of vvater t , must be under four degrees of pressure , if the vvater r , be under three . and if the air in the lowest story of a building , be under six degrees of bensil , the air in the highest story must be under five . if a man would distinguish metaphysically , and subtilly , he will find a difference of this kind , not only between the first , and second fathom of air , nearest to the earth , but between the first , and second foot ; yea , between the first and second inch , and less ; much more in water , as to sense . however it be , yet the theorem holds true ; for we find no difference sensible , between the compression of air in this room ; and the compression of air in the next room above it , no not with the baroscope , or torricellian experiment , that discerns such differences accurately . i judge it likewise to be true , in order to the next adjacent parts of fluids of different kinds ; for while a surface of mercury , is burdened with a pillar of water , or a surface of water , with a pillar of air , whatever degree of weight and pressure , is in the lowest parts of these pillars , the same is communicated entirely , to the surfaces , that sustains them . so then , there is as much force and power , in the surface of any water , as there is weight and pressure , in the lowest foot of any pillar of air , that rests upon it : otherwise , the surface of water would never be able to support the said pillar : for a surface of six degrees of force , can never be able to sustain a a pillar of air , of eight , or ten degrees of weight . theorem xxi . the pressure of fluids , may be as much in the least part , as in the whole . figure . this theorem may seem hard , yet it can be made manifest , by many instances : for albeit the quantity of air , that fills a parlour , be little in respect of the whole element , yet surely , there is as much pressure in it , as in the whole ; because experience shews , that the mercurial cylinder in the baroscope , will be as well sustained in a chamber , as without , and under the whole atmosphere directly ; which could not be , unless the small portion of air , that 's in this parlour , had as much pressure in it , as in the whole element . besides this , it will be found in a far less quantity : for though the baroscope were inclosed , and imprisoned so closs , within a small vessel , that the air within , could have no communion with the air without , yet the pressure of that very small quantity , will sustain . inches of mercury , and this will come to pass , even though the whole element of air were annihilated . this proposition is likewise evident in order to the pressure of the water : for put the case , the baroscope , whose mercurial cylinder is . inches , by the pressure of the air ; were sent down to the bottom of a sea . foot deep , within a vessel , as a hogs-head , and there exactly inclosed , that the vvater within , could have no commerce with the vvater without , yet as well , after this shutting up , as before , other . inches would be sustained , by the pressure of this imprisoned vvater , which proves evidently , that there is as much pressure in one hogs-head full of vvater , at the bottom of the sea , as in the whole element of vvater , above , or about : for an element of vvater never so spacious , if it exceed not . foot in deepness , can sustain no more mercury , then . inches by its pressure . yea , though the vessel with the baroscope , and imprisoned vvater in it , were brought above to the free air , yet will the vvater retain the same pressure , and will de facto sustain . inches of mercury , provided the vessel be kept closs . it is therefore evident , that as much pressure may be in one small quantity of vvater , as in the whole element , or ocean . 't is to be observed , that this theorem is to be understood chiefly of the lower parts of fluids ; seing there cannot be so much pressure in the vvater p , as in the vvater q ; for in effect , there is as much pressure in the vvater q , as is in the whole vvater above it , or about it . from this theorem , we see evidently , that the pressure , and bensil of a fluid , is not to be measured , according to its bulk , and quantity , seing there is as much bensil in one foot , nay , in one inch of air , as is in the whole element , and as strong a pressure in one foot of vvater , or less , as there is in the whole ocean : therefore the greatest quantity of air , hath not alwayes the greatest bensil , neither the greatest quantity of vvater , the greatest pressure . but this will appear more evident afterwards . theorem xxii . the pressure , and bensil of a fluid , is a thing , really distinct from the natural weight of a fluid . figure . this may be easily conceived ; for as in solid bodies , the bensil , and natural weight , are two distinct things , so is it in air , and water , or in any other fluid . the weight of a bow , is one thing , and the natural weight of it , is another . the weight of the spring of a watch , and the bensil of it , are two distinct things . the weight ( perhaps ) will not exceed two ounces : but the bensil ( may be ) will be equivalent to two pound . though these may illustrate , yet they do not convince : therefore i shall adduce a reason , and it 's this . the natural weight of a fluid is less , or more , as the quantity is less or more ▪ but it is not so with the pressure , because there may be as much pressure in a small quantity , as in a great , as is evident from the last theorem , therefore they may be different . the first part of the argument is manifest , because there is more weight in a gallon of water , then in a pint . a second reason is , because a fluid may lose of its pressure , without losing of its weight . this is evident from the schematism , for if you take away the four foot of water efgh , and consequently make the four pillars shorter , the foot of water q becomes of less pressure , but not of less weight , seeing the quantity still remains the same : at least , the loss of weight is not comparable , to the loss of pressure . i say , it becomes of less pressure , because there is a less burden above it . thirdly , the pressure and bensil may be intended , and made stronger , without any alteration in the weight : so is the bensil of air , within a bladder , made stronger by heat , without any alteration , in the weight of it . likewise , the pressure of the foot of water q , may be made stronger , by making these four pillars higher , without any alteration , at least considerable , in the weight ; for it still remains a foot of water , whatever be the hight of the pillars above it . lastly , the weight of a fluid is essential to it , but the pressure is only accidental ; because it is only generated , and begotten in the inferiour parts , by the weight of the superiour , which weight may be taken away . theorem xxiii . though the bensil of a fluid , be not the same thing formally with the weight , yet are they the same effectively . this proposition is true in order to many other things , besides fluids : for we see that the sun , and fire , are formally different , yet they may be the same effectively ; because the same effects , that are done by the heat of the sun , may be done by the heat of the fire . so the same effects , that are produced by the weight of a fluid , may be done by the pressure , and bensill of it . thus , the mercurial cylinder in the torricellian experiment , may be either sustained by the bensil of the air , or the weight of it . by the bensil , as when no more air , is admitted to rest upon the stagnant mercury , then three or four inches , the rest being secluded , by stopping the orifice of the vessel . by the weight of it , as when an intire pillar of air , from the top of the atmosphere , rests upon the face of the stagnant quicksilver . it is also evident in a clock , which may be made to move , either by a weight of lead , or by the force , and power of a steel spring . theorem xxiv . the surfaces of waters , are able to sustain any weight whatsoever , provided that weight press equally , and uniformly . figure . this is evident , because the imaginary surface of vvater otvx , doth really support the whole sixteen cubes of vvater above it , yea , though they were sixteen thousand , and the reason is , because they press most equally , and uniformly . vvhat i affirm of the imaginary surface , the same i affirm , of the first and visible . for let a plain body of lead , never so heavy , be laid upon the top of the vvater abcd , yet will it support it , and keep it from sinking , provided it press uniformly all the parts of that surface . it is clear also , from the subsequent theorem . theorem xxv . the surfaces of all waters whatsoever , support as much weight from the air , as if they had the weight of thirty four foot of water above them , or twenty nine inches of quick-silver pressing them . this proposition is evident from this , that the pressure of the air , is able to raise above the surface of any water , a pillar of water thirty four foot high . for , put the case there were a pump fourty foot high , erected among stagnant water , and a sucker in it , for extracting the internal air , a man will find , that the water will climb up in it four and thirty foot ; which phoenomenon could never happen , unless the surface of the stagnant water , among which the end of the pump is drowned , were as much prest with the air , as if it had a burden of water upon it thirty four foot high . the second part is also evident , because if a man drown the end of a long pipe , in a vessel with stagnant quick-silver , and remove the air that 's within the pipe by a sucker , or more easily by the help of the air-pump , he will find the liquor to rise twenty nine inches , above the surface below , which thing could never come to pass , unless the pressure of the air , upon the surfaces of all bodies , were equivalent to the pressure and weight of twenty nine inches of quick-silver . theorem xxvi . all fluid bodies have a sphere of activity , to which they are able to press up themselves , or another fluid , and no further , which is less or more , according to the altitude of that pressing fluid . figure . for understanding this proposition , let us imagine ghcd to be a vessel , in whose bottom , there are five inches of mercury efcd . next , that above the stagnant mercury , there are thirty four foot of water resting , namely abef . lastly , that upon the surface of the said water , there is resting the element of air ghab , whose top gh , i reckon to be about six thousand fathom above ab . besides these , let us imagine , that there are here three pipes , open at both ends , the first whereof cag , having it 's lower orifice c , drowned among the stagnant mercury efcd , goeth so high , that the upper orifice goeth above the top of the air gh . the second , whose lower orifice i , is only drowned among the water abef , reaches to the top of the air likewise . the third , whose open end k , is above the surface of the vvater anb , and hanging in the open air , goeth likewise above the atmosphere . these things being supposed , we see that no fluid can , by its own proper weight , press any part of it self , higher then it 's own surface , seing the stagnant mercury efcd , cannot press it self within the pipe cg , higher then e. neither can the vvater abef , press it self higher within the pipe il , then the point n. lastly , neither can the air ghab , press it self within the pipe km , higher then m ▪ but when one fluid presseth upon another , as the vvater abef , upon the mercury efcd , then doth the said mercury ascend higher than it 's own surface , namely from e to o , which point is the highest , to which the thirty four foot of vvater abef , can raise the mercury , which altitude , is twenty nine inches above the surface eif . but if a second fluid be super-added , as the whole air ghab , then must the mercury , according to that new pressure , rise by proportion ; so rises the mercury from o to p , other twenty nine inches . by this same additional weight of air , the water rises thirty four foot in the pipe il , namely from n to r. now , i say , the outmost and highest point , to which the element of air ghab can raise the mercury , is from o to p ; for by the pressure of the water abef , it rises from e to o. and the highest point , to which the said air can raise the vvater , is from n to r. the reasons of these determinate altitudes , must be sought for , from the altitudes of the incumbing and pressing fluids : for as these are less or more , so is the altitude of the mercury , and of the vvater within the pipes more or less . the hight therefore of the mercury eo , is twenty nine inches , because the deepness of the pressing water abef is thirty four foot . and the hight of the vvater nr , is thirty four foot , because the hight of the air gh , above ab , is six thousand fathom , or thereabout . and for the same reason , is the mercury op twenty nine inches . theorem xxvii . a lighter fluid , is able to press with as great burden , as a heavier . figure . this proposition is true , not only of vvater in respect of mercury , but of air in respect of them both : for albeit air be a thousand times lighter then vvater , yet may it have as great a pressure with it , as vvater ; as is evident from this second schematism , where by the pressure of the outward air ghab , twenty nine inches of mercury op are supported , as well as the twenty nine inches eo , by the pressure of the vvater abef . so doth the same air , sustain the thirty four foot of vvater nr , which are really as heavy , as the twenty nine inches of mercury op . now , if the weight of the atmosphere , be equivalent to the weight of thirty four foot of water , or of twenty nine inches of mercury , 't is no wonder to see water press with as great weight as mercury ; which is likewise clear from this same figure , where by the pressure of the water abef , twenty nine inches of mercury eo are suspended , as truly as the mercury ce , within the lower end of the pipe , is supported by the outward invironing mercury . the reasons of these phenomena , are taken from the altitudes of the pressing fluids : for though a body were never so light , yet multiplication of parts makes multiplication of weight ; which multiplication of parts in fluids , must be according to altitude : for multiplication of parts according to thickness and breadth will not do it . observe here , that if as much air , as fills the tub between n and l , were put into the scale of a ballance , it would exactly counterpoise the thirty four foot of water nr , poured into the other scale . item , that as much water as will fill the tub between e and a , is just the weight of the mercury eo . lastly , that as much air as will fill the pipe , between o and g , is just the weight of the mercury op . theorem xxviii . the pressure of fluids , doth not diminish , while you subtract from their thickness , but only , when you subtract from their altitude . figure . for understanding this , let us look upon the first schematism , where there are four pillars of water . now i say , though you cut off the three columes of water , upon the right side , yet there shall remain as much pressure , in the quadrat foot of vvater q , as was , while these were intire . but if you cut off from the top , the vvater efgh , then presently an alteration follows , not only in the lowest parts , nigh to the bottom , but through all the intermediat parts : for not only the vvater q loseth a degree of its pressure , but the vvaters p and o suffer the same loss . this theorem holds true likewise in order to the element of air. for if by divine providence , the air should become less in altitude , than it is ; then surely , the bensil of the ambient air , that we breath in and out , should be by proportion weakned also . and contrariwise , if the altitude became more , then stronger should the bensil be here , with us , in the lowest parts : both which would be hurtful to creatures , that live by breathing . for if the altitude of the air , were far more then it is , our bodies would be under a far greater pressure , which surely would be very hurtful . and upon the other hand , if the altitude of the air , were far less then it is , we should be at a greater loss ; for then , by reason of the weak bensil , we would breath indeed , but with great difficulty . theorem xxix . a thicker pillar of a fluid , is not able to press up a slenderer , unless there be an unequal pressure . figure . for understanding this , let us suppose this third schematism to represent a vessel with vvater in it , as high as ab , among which is thrust down to the bottom , the pipe gh , open at both ends . i say then , the two thicker pillars of air ea , and fb , pressing upon the surface of the vvater ab , are not able to press up the water hi , or the slender pillar of air ig within the pipe , the one higher then i , the other higher then g. if it be said , they are heavier , because they are thicker . i answer , they are truly heavier , for the pillar of air fb apart , will be thrice as heavy , as the slender pillar of air ig . but , if you reckon the pillar of air ea , upon the left hand , both together , will be six times heavier , then the air ig : yet are they not able , either severally , or con●unctly , to press up the water hi , higher then i , or the air ig , higher then g. for solving this difficulty , i must say conform to the fourth theorem , that fluid bodies , counterpoiseth one another , not according to their thickness , and breadth , but according to their altitude only : therefore , seing the slender pillar of air ig , is as high , as either fb , or ea , it cannot be prest up by them . for by vertue of this equal hight , all the three press equally and uniformly , upon the surface of water ab ; and therefore according to the twelfth theorem , there can be no motion . but if so be , the pillar fb , were higher then the pillar ig , then surely would the water hi , be prest up ; for in such a case , there is an unequal pressure . or if the pillar ig , were higher then the pillar fb , then surely would the water ih be prest down , there being again an unequal pressure : the water within the pipe , being more burdened then the water about the pipe. in a word , there 's no more difficulty here , then if the pipe were taken away : in which case , there would be but one pillar of air , resting upon the surface of water ab . if it be said , the pipe being thrust down , makes of one pillar , three distinct ones , and consequently a formal counter-ballance , or mutual sustentation . be it so , yet because all these press uniformly , there can be no motion . theorem xxx . fluids press not only according to perpendicular lines , but according to crooked lines . figure . for proving this proposition , let us suppose abcd , to be a large vessel full of vvater , as high as anb , and a little vessel lying within it , near to the bottom , closs above at m , but with an open orifice downward , as g , and having other two passages going in to it , upon the right , and left side , as eo , and fp . now , i say , the pressure of this vvater , is not only from n to m , in a straight line downwards , but from e to o , and from f to p , by crooked lines . nay , put the case this vessel had no passage in to it , but by a labyrinth , or entry full of intricate windings , yet the pressure will be communicated , thorow all these , even to the middle of it : and which is more , the vvater h or i , within the vessel , would be under the same degree of pressure , with the vvater e or l , without , or with the vvater k or f. and which is strange , let us suppose both the entries e and f stopped , and nothing remaining open , but the hole g , which i judge no wider , then may admit the hair of ones head ▪ yet thorow that smal hole , shall the pressure be communicated , to the parts of the water within , in as high a degree , as if the upper part of the vessel eml , were cut off , to let the pressure come down directly . what is true fig. . pag. ● fig. . pag. fig. pag. fig. pag. ● in order to water , the same is true in order to air , or mercury , or any other fluid . for , though a house were built never so closs , without door , or window , yet if there remain but one smal hole in it , the pressure of the whole atmosphere , shall be transmitted thorow that entrie , and shall reduce the air within the house , to as high a degree of bensil , as the air without . theorem xxxi . the pressure , and bensil of a fluid , that 's in the lowest foot , is equivalent to the weight of the whole pillar above . figure . for understanding this proposition , let us suppose ef to be the lowest foot of a pillar of air , cut off from the rest , and inclosed in the vessel ef , six inches in diameter , or wideness , and twelve inches high . now i say , the bensil and pressure , that 's in that one foot of air , is exactly of as great force and power , as is the weight of the whole pillar of air , from which it was cut off . let ab be that pillar of air , which i suppose is six inches thick , and six thousand fathom high . take it , and weight it in a ballance , and say it weighs pound , yet the pressure , and bensil , that 's in the air ef , is of as much force : and if the one be of strength by its weight , to move , v. g. a great clock , the other by its bensil , will be of as much . this proposition is true also in order to water . for put the case ef , were the lowest of foot of water : in it will be found as much pressure , and force , as will be equivalent to the weight of the whole thirty three foot , from which it was cut off . but here occurreth a difficulty ; for if the pressure , and bensil of the foot of air ef , be equivalent to the weight of the whole pillar of air ab , which weighs pound , then must the slender pillar of air cd , that 's but two inches in diameter , be as heavy weighed in a ballance , as the thicker pillar ab , which is absurd . i prove the connexion of the two parts of the argument thus : as the bensil of the air gh , is to the bensil of the air ef , so is the weight of the pillar cd , to the weight of the pillar ab : but so it is , that the bensil of the air gh , is equal in degree to the bensil of the air ef , according to the theorem . where it 's said , that the pressure of fluids may be as much , in the least part , as in the whole : therefore the pillar cd , and the pillar ab , must be of equal weight , when both are weighed together in the opposite scales of a ballance , which is false , seing the one is far thicker , and so heavier then the other . there 's no way to answer this objection , but by granting the air gh , and ef , to be equal in bensil , and yet the two pillars unequal in weight , because according to the theorem , the bensil of a fluid is one thing , and the natural weight is another . theorem xxxii . in all fluids there is a pondus and a potentia , a weight and a power , counterpoising one another , as in the staticks . that part of the mathematicks , which is called staticks , is nothing else , but the art of weighing heavy bodies ; in which , two things are commonly distinguished , viz. the pondus and the potentia , the weight and the power . 't is evident , while two things are counterpoising one another in the opposite scales of a ballance , as lead and gold , the one being the pondus , the other the potentia . the same two are as truly found in the hydrostaticks : for while the mercurial cylinder is suspended in the torricellian experiment , by the weight of the air , the one is really the pondus , the other the potentia . or while into a siphon , with the two orifices upward , water is poured , there arises a counterpoise , the water of the one leg counter-ballancing the water of the other ; this taking the name of a pondus , the other the name of a potentia . 't is evident also , while a surface of water , sustains a pillar of water , this being the pondus , that the potentia : or , while a surface of water sustains a pillar of air , the pillar of air being the pondus , and the surface of water the potentia . or , while a surface of quick-silver sustains a pillar of water or air ; the surface is the power , and either of the two is the pondus , or weight , as you please . theorem xxxiii . fluid bodies can never cease from motion , so long as the pondus exceeds the potentia , or the potentia the pondus . this is a sure principle in the hydrostaticks , which will appear most evident ; while we pass thorow the subsequent experiments , i shall only now make it appear by one instance , though afterwards by a hundred . in the torricellian experiment , lately mentioned , 't is observed , that though the pipe were never so long , that 's filled with mercury , yet the liquor subsides , and falls down alwayes till it come twenty nine inches above the surface of the stagnant mercury below . the reason whereof is truly this , so long as the mercury is higher then the said point , as long doth the pondus of it exceed the potentia of the air ; therefore the motion of it downward can never cease , till at last by falling down , and becoming shorter , it becomes lighter , in which instant of time , the motion ends , both of them being now in equipondio , or in evenness of weight . theorem xxxiv . when two fluids of different kinds are in aequilibrio together , the height of the one cylinder is in proportion to the height of the other , as the natural weight of the one is to the natural weight of the other . for understanding this theorem , we must consider , that when two cylinders of the same kind , as one of water with water , or as one of mercury with mercury , are counterpoising one another , both are of the same altitude , because both are of the same natural weight . but when the two are of different kinds , as a cylinder of air with mercury , or as a cylinder of air with water , or as a cylinder of water with mercury , then it will be found , that by what proportion , the one liquor is naturally heavier or lighter , then the othe● ▪ by that same proportion , is the one cylinder higher or lower then the other . for example , because air is reckoned times lighter then quick-silver , therefore the pillar of air that counterpoiseth the pillar of quick-silver in the torricellian experiment , is times higher . the one is inches , and therefore the other is inches : which will amount to foot , or about fathom , counting five foot to a fathom . and because air is counted times lighter then water , therefore the pillar of air that sustains the pillar of water is times higher . the hight of water by the pressure of the air is foot , and therefore the hight of the air is a thousand times foot . and because water is reckoned times lighter than mercury , therefore you will find , even by experience , that the pillar of water , that counterpoises the pillar of mercury , is times higher . for if the mercury be ten inches , the water will be exactly . if it be inches , the water will be thirty four foot . the reason is evident , because if one inch of mercury be as heavy naturally as inches of water , it follows of necessity , that for making of a counterpoise , to every inch of mercury , there must be of water , and these in altitude , each one above another . hydrostatical experiments , for demonstrating the wonderful weight , force , and pressure of the water in its own element . experiment i. figure . in explicating the phenomena of the hydrostaticks , and in collecting speculative , or practical conclusions from them , i purpose to make choise of the plainest , and most easie experiments , especially in the entry , that this knowledge , that 's not very common , and yet very useful , may be communicated to the meanest capacities . for , if at the first , any mystical , or abstruse experiments , should be proposed with intricate descriptions , they would soon discourage , and at last hinder the ingenuous reader from making progress . for , if a man do not take up distinctly , the experiment it self first , he shall never be able to comprehend next the phenomena , nor at last see the inferences of the conclusions . next , though some of the trials may seem obvious , yet they afford excellent phenomena , by which many profound secrets of nature are discovered . and if that be , 't is no matter what kind they be of . then , the grand design here , is not to multiply bare , and naked experiments ; for that 's a work to no purpose , for it 's like a foundation without a superstructure : but the intention is , not only to describe such and such things , but to build such and such theorems upon them , and to infer such and such conclusions , as shall make a stately building , and give a man in a short time a full view of this excellent doctrine . for the first experiment then , prepare a vessel of any quantity , as abcd , near half full of water , whose surface is mh . prepare also two glass-pipes , the one wider , the other narrower , open at both ends , which must be thrust down below the water , first stopping the two upper orifices e and f. this done , open the said orifices , and you shall see the water ascend in the wider to g , and in the narrower to h. now , the question is , what 's the reason , why the water did not ascend , the orifices e and f , being stopped , and why it ascends , they being opened ? to the fi●st part i answer , the water cannot ascend , because the imaginary surface of water lk is equally and uniformly prest : for with what weight the outward water ml , and hk press the said surface , with the same weight , doth the air within the two pipes press it . to the second part i answer , the water ascends , because the same surface ( the orifices e and f being opened ) is unequally prest : for the outward water ml , and hk , press it more , then the air within the pipes do . the difficulty only is , why it is equally prest , the orifices e and f being stopped , and why it is unequally prest , the said orifices being once opened . to unloose the knot , i must shew the reason , why the air within the pipes , press the surface lk , with as great a burden , as the outward water press it . for understanding this , you must know , that when the orifice i is thrust down below the water , there ariseth a sort of debate between the lower parts of the water , and the air within the pipes , the water striving to be in at i , and the air striving to keep it out : but because the water is the stronger party , it enters the orifice i , and causeth the air retire a little up , one fourth part , or sixth part of an inch , above i , and no more , which is a real compression it suffers . for the orifice e being stopped , hinders any more compression , than what is said ; in which instant of time the debate ends , the air no more yeelding , and the water no more urging ; by which means the air having obtained a degree of bensil , more then ordinary , by the pressure of that little quantity of water , that comes in at i , presseth the part of the imaginary surface , it rests upon , with as great weight , as the outward water presseth the parts it rests upon . but when the orifice e is opened , the outward water ml , and hk , press the imaginary surface lk more , than the air within the pipe can do . and the reason is , because by opening the orifice above , the internal air , that suffered a degree of bensil more then ordinary , presently is freed , and consequently becomes of less force , and weight ; which the water finding , that hath a little entered the orifice i , instantly ascends to g , it being less pressed , then the water without the pipe. now the reason , why it ascends no higher then g , is taken from the equal pressure of the body that rests upon the surface mgh : for , assoon as it comes that length , all the parts of the horizontal plain of water , is uniformly prest with the incumbing air , both within the pipe , and without the pipe. the water in going up , cannot halt mid-way between i and g , for then there should be an unequal pressure in fluids without motion , which is impossible ; for the water is still stronger then the air , till once it climb up to g. from this experiment we see first , that in water there is a pressure and force ; because having opened the orifice e , which is only causa per accidens of this motion , the water is prest up from i to g. we see secondly , that fluid bodies , can never cease from motion , till there be an equal pressure among the parts , which is evident from the ascent of the water from i to g , which cannot halt in any part between i and g , because of an unequal pressure , till it once climb up to g. we see thirdly , that fluid bodies do not sustain , or counterpoise one another according to their thickness and breadth , but only according to their altitude ; because there is not here any proportion between the slender pillar of water hk within the pipe , and the outward water that sustains it , i means as to the thickness ; therefore 't is no matter , whither the glass tubs be wider or narrower , that are used in counterpoising fluid bodies one with another . and this is the true reason , why 't is no matter , whither the tub of the baroscope be a wide one , or a narrow one , seing the air doth not counterpoise the mercury , according to thickness , that 's to say , neither the thickness of the ambient air that sustains , nor the thickness of the mercury that is sustained , are to be considered ; but only their altitudes . 't is true , the element of air is fourteen thousand times higher , then the mercurial cylinder , yet there is a certain and true proportion kept between their heights ; so that if the element of air , should by divine providence become higher or lower , the height of the mercury would alter accordingly . experiment . ii. figure . take out of the water , the wide pipe egi , and stopping the orifice i , pour in water above at e , till the tub be compleatly full . having done this , thrust down the stopped orifice i to the bottom of the vessel , and there open it , then shall you see the water fall down from e to g , and there halt . the reason is taken from unequal pressure ; for the tub being full of water from e to i , that part of the imaginary surface , upon which the pillar of water rests , is more burdened than any other part of it , namely more then l or k ; therefore seing one part is more burdened than another , the cylinder of water that causeth the burden , must so far fall down , till all the parts be alike prest , in which instant of time , the motion ceaseth . this leads us to a clear discovery of the reason , why in the baroscope , the mercury falls from the top of the tub of any height , alwayes to the twentieth and ninth inch , above the stagnant quick-silver . for example , fill the pipe nq , which is sixty inches high with mercury , and opening the orifice q , the liquor shall fall out , and fall down from n , till it rest at r , which is twenty nine inch above the open orifice q. the reason is the same , namely unequal pressure , seing one part of the imaginary surface of air xs , upon which the cylinder of mercury stands , is more burthened then the other next adjacent : therefore , so long and so far must the mercury subside and fall down , till the part q , upon which the basis of the pillar rests , be no more burthened , than the rest of the parts ; in which instant of time , the motion ceaseth , and there happeneth an equal ballance , between the silver within the tub , and the air without . if it be said , i see a clear reason , why the outward water ml , ought to sustain the inward gi , but cannot see , why the outward air tzs and vrx , ought to sustain the inward mercury rx : neither do i see a reason , why it should halt at r , as the water rests at g. i answer , though sense cannot perceive the one , as evidently as the other , yet the one is as sure as the other . for taking up the reason why it halts at r , inches above x , you must remember , from the theorem , that the pressure of the air upon bodies , is equivalent to the weight of foot of vvater perpendicularly , or inches of quick-silver . the pillars of air then tzs , and vrx , being as heavy each one of them , as two pillars of mercury , each one of them inches high , it follows of necessity , that the mercury within the tub , must be as high as r. 't is no wonder to see the silver halt at r , provided rx , and zs , were two bulks of mercury , environing the pipe , as the outward vvater environs the wider and narrower pipe. neither ought any to wonder , when the silver falls down , and rests at r , nothing environing the pipe but air , seing the pressure of the air is equivalent to the weight of inches of quick-silver . this experiment is easily made : take therefore a slender glass-pipe of any length , beyond inches , open at both ends ; but the lower end q , must be drawn so small by a flame of a lamp , that the entry may be no wider , than may admit the point of a small needle , or the hair of ones head . then stopping the said orifice , pour in mercury above at the orifice n , till the pipe be compleatly full . next , close the said orifice with wet paper , and the pulp of your finger ; and opening the lower orifice , you shall find , ( which is very delightful to behold ) the mercury spring out , like unto a small silver threed , and falling down from the top n , shall rest at r , the motion ceasing at the narrow orifice q. this shews evidently , that there is not need alwayes of stagnant mercury , for trying the torricellian experiment ; but only when the mouth of the pipe below is wide : for being narrow , the silver runs slowly out , and consequently subsides slowly above , and coming down slowly to r , there rests . but when the mouth is wide below , the silver falls down so quickly , that it goes beyond r , before it can recover it self , which recovery would never be , unless there were stagnant mercury to run up again . from what is said , we see first , that when one part of a surface of water or air , is more burthened than another , the burthened part presently yeelds , till it be no more burthened than the other . this is clear from the falling down of the water from e to g , which cannot be supported by the part i , because more burthened than the rest . we see secondly , that the element of air , rests upon the surfaces of all bodies with a considerable weight ; otherwise it could not sustain the water , before it fall down from e to g : for if it did not rest upon the surface mh , with weight , the water could never be suspended ; seing the application of the finger to the orifice e , is only the accidental cause of this sustentation . we see thirdly , that according to the difference of natural weight , between two fluids , so is the proportion of altitudes between two of their cylinders : therefore air being reckoned times lighter then mercury , it followes that the cylinder of mercury sustained by the air , must be times lower and shorter , than the cylinder of air that sustaines it ; which appears from this experiment to be true , seeing by the pressure of the air , which is thought to be about fathom high , inches of mercury is supported between r and x. in a word , if air be naturally times lighter than mercury , which is very probable ; then must the altitude of it , commonly called the atmosphere , be fourteen thousand times , nine and twenty inches , that is , or of feet . experiment iii. figure . while the outward , and inward water are of the same altitude , withdraw the inward air eg by suction , or by any other device you think fit , and you will find the water rise as high as e , which i suppose to be foot above mgh . the same phenomenon happens , in taking the air out of the narrow pipe fk . the reason is still unequal pressure ; for in removing the air , that 's within the pipe , the part of the surface m , and the part h , remaines burthened , while the part g is freed of its burden : therefore this part of the surface , being liberated of its burden , that came down through the pipe , instantly rises , and climbs up as far , as the outward air resting upon m and h , can raise it , which is to e foot : for the pressure of the air upon the surfaces of all waters , according to the theorem , being equivalent to the weight of foot of water , must raise the said water in the pipe foot . you do not wonder , why it rises from i to g , as in the first experiment ; no more ought you to wonder , why it rises from g to e , seing the weight of the air , doth the same thing , that foot of water resting upon the surface mh , would do . from this experiment we see first , that the pressure of the air , is the proper cause of the motion of water , up thorow pumps and siphons , or any other instrument , that 's used in water-works of that kind ; for if the weight of the air , resting upon the surface mh be the cause , why the water climbs up from g to e , the same must be the cause , why the stagnant water followes the sucker of the pump , while it 's pulled up . and the same is the cause , why water ascends the leg of a siphon , and is the cause , why motion continues after suction is ended . we see secondly , that every pressing fluid hath a sphere of activity , to which it is able to raise the fluid , that is pressed . this is evident in this experiment , because the pressure of the air resting upon mh , is able to raise the water , the hight of e in the wide pipe , and the hight of f in the narrow , and no further , even though the said pipes were far longer : and this altitude and highest point is precisely foot between air and water . we see thirdly , that 't is all one matter , whether pumps and siphons be wider or narrower , whether the tub of the baroscope be , wherein the mercury is suspended , of a large diameter , or of a lesser diameter . this is also evident from the same experiment ; seing there is no more difficulty in causing the water ascend the wide pipe , than in causing it ascend the narrow one . and the reason is , because the pressing fluid repects not the pressed fluid , according to its thickness and breadth ; but only according to its altitude . therefore'its as easie for the air , to press up water through a pump four foot in diameter , as to press it up through a pump , but one foot in diameter . experiment iv. figure . this schematism represents a large vessel full of water , whose first and visible surface is dehk . the second , that 's imaginary is , li , six foot below it . the third of the same kind , is mg , six foot lower . the fourth , is nfo , six foot yet lower . the last , and lowest , is abc . there are here also four tubs , or rather one tub under four divers positions , with both ends open . after this tub da is thrust below the water , till it ascend , as high as d in it , lift it up between your fingers , till it have the position of the second pipe ef , and then you shall see , as the orifice of the pipe ascends , the cylinder of water fall out by little and little , until it be no longer than ef. again , lift it further up , till it have the position of the pipe hg , then shall you find the cylinder of water become yet shorter . lastly , if it be scituated , as the pipe ki , the internal water becomes no longer than ki . the reasons of these phenomena are the same ; namely unequal pressure ; for the orifice a being lifted up as high as f , it comes to the imaginary surface no , which is not under so much pressure , as the other is ; therefore one part of it being more burdened , than another , namely the part upon which the cylinder of water rests , it presently yeelds , and suffers the cylinder to become shorter , and lighter , till it become no heavier , then is proportionable to its own strength . to make this reason more evident , it is to be noted , that no surface of water is able to support a cylinder higher then its own deepness , that is to say , if a surface be foot deep , it is able to sustain a cylinder foot high , and no more : therefore the surface no , being but foot deep , it cannot sustain a cylinder foot long : for if that were , then the potentia , should be inferiour to the pondus , which is impossible in the hydrostaticks . in effect , it were no less absurdity , then to say , ounces are able to counterballance . for a second trial , lift up the same pipe higher , till it acquire the position of the tub gh ; in this case , the cylinder of water within it , becomes yet shorter , even no longer , than gh . the reason is the same , namely unequal pressure ; for when a cylinder of water foot high , comes to rest upon this surface , that is but foot deep , it makes one part of it more burdened then another ; therefore the part that is more prest , presently yeelds , and suffers the cylinder to fall down , till the pondus of it , become equal to its own potentia . for the last trial , lift up the tub , till it acquire the position of the pipe ki : in this case , the water within it becomes no longer then ki , the surface li , that is but six foot deep , not being able to sustain a cylinder foot high . from this experiment we see first , that in all fluid bodies there is a pressure , which is more or less , according to the deepness of that fluid ; this is evident from the four several surfaces ; there being more pressure and force in the lowest abc , then in the next no ; and more in this , then in the surface mg ; and more in this , then in li. we see secondly , that in all fluids , there is a pondus and a potentia ; which two are alwayes of equal force , and strength ; the potentia is clear and evident in the surface , by supporting the pillar ; which pillar is nothing else , but the pondus supported . and that they are alwayes of equal strength , is most evident also ; for when you endeavour to make the pondus unequal to the potentia , in making a surface foot deep , to support a pillar foot high , they of their own accord become equal ; the pillar becoming shorter , and suitable to the strength of the surface that sustains it . we see thirdly , that 't is impossible for one part of the same horizontal surface , to be more burdened then another : for when you endeavour to do it , by setting a longer pillar upon it , the part burdened instantly yeelds , till it be no more prest , then the next part to it . we see fourthly , that the inequality , that is between the pondus and the potentia in fluids , is the proper cause of the motion of fluids . for when you endeavour to make a surface foot deep , sustain a pillar foot high , this inequality is the true cause , why the pillar subsides , and falls down , and why the surface yeelds , and gives way to it . and this inequality is the true cause , why the motion of water thorow siphons continues . for understanding this , you must conceive a siphon , to be nothing else , but a crooked pipe with two legs , the one drowned among water , the other hanging in the open air. the use of it is , for conveying wine or water from one vessel to another , which is easily done by suction . now after suction is ended , the motion of the water continues , till the surface become lower , then the orifice out of which it runs . the true reason then , why the water flows out , is the inequality between the potentia of the air , and the pondus of the vvater ; the pondus being stronger then the potentia . for in air as in vvater , we must conceive horizontal surfaces ; and these surfaces to be endowed with pressure and force , as are the surfaces of vvater . now when the leg of a siphon is hanging in the air , it must rest upon one surface or another , and consequently the vvater in it , must rest upon the same surface . if the potentia of the surface be stronger , then the pondus of the vvater ; the vvater is driven backward , which alwayes comes to pass , when the orifice is higher , then the surface of the vvater of the vessel , among which the other leg is drowned . if the potentia of the surface of that air , be of equal power and strength , with the pondus of the vvater , the vvater goeth neither backward , nor forward , but stands in equilibrio : this happens , when the orifice is neither higher , nor lower , than the surface of the vvater in the vessel . but if the potentia of the surface of the air be weaker , than the pondus of the vvater ; in this case , the air yeelds , and suffers the vvater to run out , even as a surface foot deep , yeelds to a pillar of vvater foot high . the same inequality is the reason , why vvater climbs up the pump ; why vvater climbs up a pipe , when a man sucks with his mouth . before suction , the potentia that 's in the surface of vvater , among which the end of the pipe is drowned , is of equal force with the pondus of the pillar of air , that comes down thorow the pipe , or pump ; but assoon as a man begins to suck , the said pillar of air becomes lighter ; and the vvater finding this , presently ascends . the same is the reason , why the mercury falls down to inches in the baroscope , and no further : for as long as the pondus of the pillar of mercury , exceeds the potentia of the surface of air , so long doth the motion continue ; and when both are become equal in force , the motion ceaseth . vvhen the glass-tub is inches long , and filled with mercury , and inverted after the common manner , you are endeavouring as it were , to cause a surface inches deep , sustain a pillar inches high , which is utterly impossible in fluids . it is judged by many a wonder to see the deflux of the mercury in the baroscope ; but in effect , there 's no more cause of admiration in it , than to see the cylinder of water grow shorter , by lifting the pipe up from one surface to another . from this experiment , we see the true reason , why the mercurial cylinder of the baroscope becomes shorter and shorter , according as a man climbs up a mountain with it . for at the root of the hill , the surface of air , that sustains the pillar of mercury , is of greater force , than the surface at the middle part : and this is stronger than any surface at the top . the pipe therefore being carried up from one surface to another , the mercury in it , must subside , and full down , even as the water falls down , and becomes shorter , by lifting the pipe from the surface abcd to the surface no . and as the whole vvater would fall down , if the orifice i , were lifted above the surface dehk , so i● the baroscope could be carried so high , till it came above the top of the air , the whole mercurial cylinder would surely fall down . and as by thrusting down the said pipe to the bottom of the vessel again , as the pipe da , the vvater ascends in it ; so by bringing down the baroscope to the earth again , the whole inches would rise again . experiment v. figure . fill the vessel adgh with vvater to the brim . next , thrust down the open orifice of the tub da , to the bottom , and you shall see the vvater ascend in it , as high as d , according to the first experiment . when this is done , recline the said pipe , till it ly as be , and you shall find the pipe , compleatly full of vvater . next , erect the same tub again as da , and you shall see the cylinder of vvater fall down , and become shorter , as at first . for salving this phenomenon , and such like , i must suppose this vvater to be inches deep , and the tub ia , and be inches long : and the said tub in reclining , to describe the quadrant of a circle feg . now the question is , why there being but inches of water in the tub , while erected , there should be in it , when it is reclined ? secondly , why there should be inches of water in the tub be , and but in it , when it stands perpendicular , as da ? if you reply , because there are inches in recta linea between the point b , and the point e , and but between a and d. but this will not answer the case ; because , if you stop the orifice e , with the pulp of your finger , before it be erected , you will find the tub remain full of vvater , even while it stands perpendicular ; and fall down , when the orifice is opened . or , while the tub stands perpendicular , stop the orifice i , and recline it as be : yet no more water will be found in it , than inches : but by unstopping the said orifice , the vvater climbs up from r to e , and becomes inches . now , what 's the reason , why it runs up from r to e , and why it falls down from i to d ? i answer then , the vvater must run up from r to e , because of the inequality , that 's between the pondus of the cylinder br , and the potentia of the surface of vvater abc , that supports the said cylinder . for understanding this , know , while the tub is erected , there is a perfect equality , between the weight of the pillar ad , and the force or power of the surface that sustains it , seing a surface inches deep , supports a pillar inches high . but assoon as the tub is reclined , there arises ane inequality between the saids two parties , the pondus of the cylinder becoming now less than before . if you say the quantity of the vvater is the same , namely inches , in the reclined tub , as well as in the perpendicular . i grant the quantity is the same , but the weight is become less . now the reason , why the same individual vvater , is not so heavy as before , is this ; there are ounces of it , supported by the sides of the tub within ; which were not , while the tub was erected : for in this position , the whole weight of the cylinder rests upon the surface : but while the tub is reclined , the said surface is eased , and freed of ounces of it ; this , resting and leaning upon the sides of the pipe within . the surface then , finding the said cylinder lighter now than before , instantly drives it up from r to e , inches . and likewise , when the reclined pipe is made perpendicular , the water falls down from i to d , because of the inequality , that 's between the pondus of the pillar , and the potentia of the surface ; this surface inches deep , not being able to support a pillar inches high , for if this were , then one part , should be more burthened than another , which is impossible . it is to be observed , that by how much the more , the tub is reclined from a perpendicular , towards the horizontal surface abc , by so much the more growes the inequality , between the pondus and the potentia , and that according to a certaine proportion hence is it , that the tub being reclined from degrees to , there arises a greater inequality between the pondus of the cylinder , and the potentia of the surface , than while it is reclined from to : and more yet in moving from to , than in moving from to , and so downward , till it be horizontal , in which position , the whole pondus is lost . and contrariwise , while the pipe is elevated , the pondus begins to grow ; and growes more , being lifted up from to , than from to : and yet more in travelling from to , than from to , and so upwards , till it be perpendicular , in which position , the cylinder regaines the whole pondus and weight , it had . this proportion is easily known , for it s nothing else , but the proportion of versed sines upon the line fb ; for according to what measure , these unequal divisions become wider , and wider from to , according to the same proportion does the pondus of the cylinder become less and less : and contrariwise , according to what proportion the said divisions become more and more narrow from to , according to the same measure and rate , does the pondus of the cylinder become greater and greater . from this experiment we see first , that two cylinders of fluid bodies , differing much in quantity , may be of the same weight : because though the cylinder be inches long , be far more in quantity , than the cylinder da , that 's but , yet both of them are of the same weight , in respect of the surface that sustaines them . if it be said , the one is really heavier , than the other , notwithstanding of all this . i answer , it is so indeed , in respect of the libra , or artificial ballance , that we commonly use in weighing of things : but it is not so in respect of this natural ballance , if i may so speak , wherein fluid bodies are onely weighed after this manner . we see secondly a clear ground for setting down the ninth theorem , namely , that in all fluid bodies a twofold weight may be distinguished , one sensible , another insensible : because the sensible weight of the cylinder of water be , remaines still the same , even though it should be reclined to g ; for take it out , and weigh it in a ballance , it will be as heavy the one way as the other . but it is not so with the insensible weight ; seeing the tub begins no sooner to recline , but assoon it begins to diminish , and grows less . this insensible weight is nothing else , but the sensible weight considered after another manner . for look upon the weight of the pillar of water be , as it weighs in a pair of scales , it is then sensible , and weighs so many ounces , and cannot be more or less : but look upon it in reference to the potentia of the surface , that sustains it , it is then insensible as to us : for though a man should put his hand below the water , and endeavour to find the weight of the said pillar , yet he shall not find it , though that part of the surface upon which it rests , doth really ( if i may so speak ) find the weight of it . and as it is insensible , so is it sometimes more , and sometimes less , according as the tub is elevated , or reclined : now these two being put together , gives a very probable ground for this distinction . we see thirdly , that the pondus or weight of fluids , doth not only press according to perpendicular lines , but according to lines falling obliquely upon the imaginary surface ; so doth the weight of the pillar of water be , press the surface abc . we see fourthly , that fluid bodies , do counterpoise one another , according to altitude only : for put the case , the pipe be , were ten times wider then it is , yet will the surface sustain the water in it , provided the pipe keep still the same position of altitude , namely degrees : the reason seems to be this ; for if the base of the pillar become more in diameter , it necessarily requires a larger part of the surface to rest upon ; which larger part is really stronger than the lesser part , as will be shewed afterwards . from this experiment we see lastly , an evident reason , why the mercurial cylinder in the baroscope runs up , and fills the empty space , when the pipe is reclined , and why it runs down , when the tub is erected again . in effect , the reason is the same , namely , an inequality between the pondus of the quick-silver , and the potentia of the surface of the air : for when the tub begins to recline , the pondus begins to rest upon the side of the tub within ; by which means the potentia of the surface finding the burden less , instantly thrusts up the stagnant mercury to supply that loss , seing two fluids cannot counterpoise one another , unless they be in aequilibrio . and contrariwise , assoon as the tub begins to be erected , the pondus of the mercury begins to grow , and so overcomes the potentia of the surface , till by falling down it can do no more . experiment vi. figure . this schematism represents a vessel full o● water , whose first and visible surface is hik ; the second , which is imaginary , is efg : the third , abcd. fig. pag. fig. pag. fig. pag. fig. pag. besides these three in water , conceive a fourth in the air , above the water , namely lmn . upon this aërial surface , rests the orifice m , of the tub tm , open above . upon the surface efg , is standing the mouth f , of the pipe sf . and upon the surface abcd , stands the pipe rb , open at both ends . after the orifice b is drowned below the vvater , you will find the liquor rise from b to h. then close with the pulp of your finger the mouth r , and lift the pipe so far up , till it have the position of the pipe sf ; and you shall see the vvater hing in it between f and o. lastly , bring the said orifice compleatly above the vvater , till it have the position of the tub tm ; yet shall the vvater still hing in it , as mp . the first question is , what sustains the vvater io ; for the part fi , is sustained by the ambient vvater ? i answer , it cannot be the pulp of the finger closing the orifice s ; for though , by taking away the finger , the vvater oi falls down , and by putting to the finger , it is keeped up , yet this proves not the pulp of the finger to be the principal , and immediat cause . i say then , the vvater oi is suspended by the weight of the incumbing air , resting upon the surface hik . for understanding this , consider , as i said before , . theorem , that the pressure of the air upon all bodies , is just equivalent to the weight of . foot of vvater . hence then is it , that if the air be able to sustain a pillar of vvater , foot high , it must be able to sustain the short pillar oi , that exceeds not four foot . the second question is , whether the part f , be equally burthened with the part e , or g ; for it would seem not , seing the vvater oif , is but four foot high ; whilest upon e or g is resting , not only more then a foot of vvater to the top hik , but the whole weight of the atmosphere upon the said top is resting , which is equivalent to the burden of foot of vvater . i answer , there 's more to be considered , than that four foot of vvater , which in it self is but of small burden , therefore to this we must add the weight of the air between o and s , within the pipe ( remember that the orifice s is stopped with the pulp of the finger ) which in effect will be as heavy as foot of vvater . put the case then , f , to be one foot below the first surface hik , and the vvater oi to be three foot , then ought the air os , to have the weight of foot , because the surface efg is able to support a pillar of foot . this i prove , because the part e , de facto , sustains foot , because the air above is equivalent to foot of it , and there is a foot of vvater between it and the top , namely between e and h. the third question is , how it comes to pass , that the water still remains in the pipe , after the orifice m is brought above the surface of the water ; for there is here no stagnant water guarding it , as guards the orifice f. i answer , that the base m , of this pillar of water pm , as really rests upon the horizontal surface of this air lmn , as a cylinder of brass or timber rests upon a plain marble table , and after the same manner . remember that the orifice t is stopped all this time , with the pulp of the finger . if it be said , that the part m , is more burdened then the part n , seing it sustains four foot of water , which the part n supports not , and the air pt within the pipe also , which is of as much bensil and pressure , as the air ny is of . for clearing of this difficulty , consider , that the pillar pm is shorter now than before ; for the orifice m coming up from d , some inches of water falls out , as will be found by experience . suppose then , that of four foot , six inches fall out ; if this be , then the inclosed air between p and t , must be six inches longer , if this be , then of necessity the bensil of it must be proportionably remitted and slackened : whence follows by metaphysical necessity , that it cannot burden the water pm , with as much weight as it had , and consequently the surface of air cannot be so much burdened . it must then be no more bu●dened with them both together , than it is with the single pillar of air yn . if then the water pm , be three foot and an half , the weight of the enclosed air tp , must be exactly the weight of thirty foot of water and an half . from this experiment , we see first the pressure of the air , for by it the water oi is suspended , and by the same pressure is the water pm suspended . we see secondly , that in air , there is a power of dilating it self , and that this dilatation never happens , without a relaxation of the bensil . we see thirdly , that one fluid cannot sustain another , unless the potentia of the one , be equal to the pondus of the other , as is clear from the aërial surface , that cannot sustain the whole four foot of water , but suffers six inches of it to fall out , that the pondus of the rest , and the air above it , may become equal to its own potentia . we see fourthly , that fluid bodies have not only a power of pressing downward , but of pressing upward likewise : as is clear from the water oi , that 's suspended by the air pressing down the surface of water hik . it presseth upward also , while it supports the water pm . this experiment also answers a case , namely , whether or not , it is alwayes needful to guard the orifice of the tub of the baroscope with stagnant quick-silver ? i say then , it is not alwayes needful , provided the orifice be of a narrow diameter ; for experience tells , that while it is such , the mercury will subside , and halt at inches above the orifice , though no stagnant mercury be to guard . in making this trial , the orifice must be no wider , than may admit the point of a needle . or suppose it to have the wideness of a tobacco-pipe , yet will the mercury be suspended , though the end be not drowned among stagnant quick-silver , even as the water pm , is kept up without stagnant water about it . for trial of this , you must first let the end of the pipe , be put down among stagnant mercury , and after the cylinder is fallen down to its own proper altitude , lift up the pipe slowly , till the orifice come above the surface , and you will find , provided you do not shake the pipe , the cylinder to be suspended after the same manner , immediatly by the air , as the water pm is . experiment vii . figure , . take a vessel of any quantity , such as abcde , and fill it with vvater . and a glass-pipe , such as gfd , of or inches long , of any wideness , closs above , and open below . before you drown the open end among the vvater , hold the glass before the fire , till it be pretty hot , and having put it down , you will see the vvater begin to creep up till it come to f , where it halts . the question now is , what 's the reason , why the vvater creeps up after this manner , or inches above the surface ab ? i answer , the heat having ra●ified the air within , and by this means , having expelled much of it , and the air now contracting it self again with cold , the vvater ascends , being prest up with the weight of the incumbing air , resting upon the surface of water ab . there is here surely an inequality between a pondus and a potentia , that must be the cause of this motion . i judge then the inequality to consist between the weight of the air within the pipe , and the surface of water cde . to explicate this , i must suppose the pipe to be thrust down cold ; in this case , little or no water can enter the orifice d. and the reason is , because the pondus of the air within the glass , is equal to the potentia of the surface cde . but when the pipe is thrust down hot , much of the air having been expelled by the heat , and now beginning to be contracted by cold , the pondus of the air becomes unequal to the potentia of the surface , and therefore this , being the stronger party , drives up the air within the glass , till by this ascent , the pondus of the air gf , and the pondus of the water fd together , become equal to the potentia of the surface cde , that sustains them . for a second trial ; bring a hot coal neat to the side of the glass , between g and f , and you will find the water to creep down from f toward the surface ab ; and if it continue any space , it will drive down the whole water , and thrust it out at d. to explicate this , i must suppose that heat , by rarifying the air within the glass , intends and increaseth the bensil of it , and the bensil being now made stronger , there must arise an inequality between the pondus of the said air , and the potentia of the surface cde ; the air then , being the stronger party , causeth the surface to yeeld . by comparing this experiment with the former , we see a great difference between the dilatation of air , of its own accord , and by constraint . for while it is willingly expanded , the bensil begins to grow slack , and remiss , and loseth by degrees of its strength ; even as the spring of a watch by the motion of the wheels , becomes remiss . but when the dilatation is made by heat , and the air compelled to expand and open it self , the bensil becomes the stronger , and the pressure the greater . notwithstanding , though the bensil of this inclosed air gf , may be made stronger by heat , to the expulsion of the water fd , yet if this rarefaction continue any time , the bensil becomes dull and slack . and the reason is , because air cannot be expanded and opened to any quantity ; an inch cannot be dilated and opened to an hundred , or to a thousand : neither can the bensil of it be intended , and increase to any degree , v.g. from one to , , or . and therefore , as the expansion grows , the bensil must at length slacken . but if so be the air were inclosed , as in a bladder knit about the neck with a string , then the more heat , the more bensil : for in this case there is a growth of pressure , without dilatation . and sometimes the bensil may be so intended with the heat , that the sides of the bladder will burst asunder . from this experiment we see first a confirmation of the theorem , namely , that there may be as much bensil and pressure , in the smallest quantity of a fluid , as in the greatest ; as is clear from the bensil of the air gf , which in effect counterpoiseth the weight of the whole atmosphere , resting upon the surface of water ab . we see secondly , that when the pondus , and the potentia of two fluids , are in equilibrio , or of equal strength , a very small addition to either of them , will cast the ballance . for if a man should but breath softly upon the side of the glass between g and f , or lay his warm hand to it , the said air will presently dilate it self , and by becoming thus stronger , thrust down the water , and so overcome the potentia of the surface . we see thirdly a confirmation of the sixth theorem , namely , that the pressure of fluids is on every side ; as is clear from the inclosed air gf , that not only presseth down the water fd , but with as great force presseth up the top of the glass within , and presseth upon all the sides of it within , with the same force . this experiment also , leads us to the knowledge of two things : first , of the reason , why with cold the water ascends in the common weather-glasses ; and why in hot weather the water descends . secondly , from this experiment we may learn to know , when the air is under a greater pressure , and when under a lesser : because when the air becomes heavier , as in fair weather , the water creeps up in some measure , it may be two or three inches ; when there is no alteration as to heat and cold : and in foul weather , or in great winds , when the air is really lighter , the said water creeps down as much . if it be asked , how shall i know , whether it be the cold of the air , or heaviness of the air , that causeth the water to ascend ; and whether it be the heat of the air , or the lightness of the air , that causeth the water to descend ? i have proposed this question of purpose , to let you see a mistake . many believe , that the ascent and descent of water in common weather-glasses , is allanerly from the heat and coldness of the air ; and therefore they conclude a cold day to be , because the water is far up : whereas the water hath ascended since the last night , by reason of a greater weight in the air , which alwayes is , when the weather is dry , and calm , though there hath been no alteration of heat to cold . if it be asked , how come we to the knowledge of this , that the pressure and weight of the element of air , is sometimes less , and sometimes more ? i answer , this secret o nature , was never discovered , till the invention of the torricellian experiment , otherwise called the baroscope . for after the falling down of the quick-silver to inches ▪ if you suffer it to stand thus in your parlour or chamber , according as the pressure , and weight of the element of air , becomes more or less , so will the altitude of the mercury become less or more , and vary sometimes above inches , and sometimes below . this alteration is very sensible , which is sometimes the tenth part of an inch , sometimes the sixth , and sometimes the third , according as the weight of the air is less or more . from december to february , i found the alteration become less and more from inches to , which will be three fingers breadth . the common weather-glasses then are fallacious , and deceitful , unless they be so contrived , that the pressure of the air cannot affect them , which is easily done by sealing them hermetically , and in stead of common water , to put in spiritus vini rectificatissimus , or the most excellent spirit of wine , and strongest that can be made . it may be here inquired , whether or not , mercury would ascend in this glass , as the water does ? i answer it would ; because the ascent depends only upon the pressure of the air , incumbing upon the stagnant liquor in the vessell , that 's able to drive up mercury as well as water . it may be inquired secondly , how far mercury will ascend , and how far water will creep up ? i answer , mercury can ascend no higher in a tub , than inches ; and water no higher , than foot ; and this onely happens , when there is no air above the tops of the cylinders to hinder their ascents . but when there is air , as gf above the liquor , it can go no higher , than the point to which the cold is able to contract the inclosed air , which is in this glass , the point f. it may be inquired thirdly , which is the greater difficulty , whether or not mercury , will rise as easily in a tub as water ; for seeing , it s times heavier , it seemes the air should have greater difficulty to press it up , than to press up water ? i answer , 't is greater difficulty for the air to press up inches of mercury , than to press up inches of water ; yet it s no greater difficulty , for the air to press up inches of mercury , than to press up foot of water , because the burden and weight is the same . it may be inquired fourthly , whether or not , it be as easie for the air , to press up a thick and gross cylinder of water , as to press up a thin and slender one ? for example , whether is it as easie for the air to press up a cylinder of water inches in diameter , and foot high , as it is to press up one , two inches in diameter , and foot high ? i answer , there is no more difficulty in the one , than in the other : and the reason is , because fluid bodies do not counterpoise one another according to their thickness , but only according to their altitude , according to the fourth theorem . therefore seeing the slender cylinder is as high as the grosser , it must be no more difficult to the air , to press up the one then the other . there is one difficulty yet remaining , which is truely the greatest of all ; namely what 's the reason , why its more difficult to the air , to press up inches of mercury , than to press up inches of water : or more difficult to the air , to press up inches of mercury , than to press up ? i answer , this comes to pass , because the air is more burthened with inches of mercury , than with . now , if this be , then surely it must be more hard to the air , to do the one , than to do the other : even as it is more hard ; for a man , to lift up from the ground , pound of iron , than to lift up or . the case may be better illustrated after this manner . suppose a man standing on the ground , with a rope in his hand , coming down from a pulley above , drawing up a weight to the top of the house : put the case likewise , the weight be a stone of pound , and the weight of it , to increase successively , as it is pulled up . now its easie for the man to pull up the stone the first fathom ; because it is but pound weight : but the stone becoming pound in the second fathom , and in the third , and in the fourth and so forth , untill it become , he will find the greater difficulty , the longer he pulls . 't is just so with air , or water , raising mercury in a tub ; for as the cylinder of the mercury grows higher by rising , so it becomes heavier , and consequently the imaginary surface , upon which the base of the pillar rests , is more and more burdened , and so becomes less and less able to press it up . this leads us to a clear discovery of the reason , why 't is more difficult by suction , to pull up mercury in a pipe , than to pull up water ; and more hard to suck up ten foot of water , then to suck up five . for trial of this , which is soon done , take a slender glass-pipe or inches long , open at both ends , and drown the one end among quick-silver , and put your mouth to the other , and having sucked , you will find greater difficulty to pull up thorow the pipe inches of mercury , than to pull up , or ; and far greater difficulty to suck up , than to pull up . it may be objected , that if a man had strength sufficient in his lungs , to suck out the whole air of the pipe , thirty inches of mercury would come as easily up , as three , which seemes to prove , that the difficulty of the mercurie's up-coming , depends not upon the weakness of the air , but upon the weakness of the lungs , and want of strength to suck . i answer , though a man were able to suck out the whole air of the pipe , yet inches , will never ascend so easily , as ten , nor ten so easily as three ; and that for the reasons already given . but why is it then , ( say you ) that the stronger the suction be , the higher the mercury ascends in the pipe ? i answer , the suction serves for no use , but to remove the impediment , that hinders the mercury from coming up , which is nothing else , but the air within the pipe. now , the more of this air that 's taken away by suction , ( the stronger the suction is , the more air is taken away ) the farder up comes the mercury . but why ought there to be difficulty in the suction of mercury , to the altitude of or inches , more than in the suction of water to that altitude ? i answer , when i suck water up thorow a pipe , the suction of the air above it , is easie ; because the ascending water helpes much to drive it up to the mouth , the outward air driving up both . but the suction is difficult in mercury , because the ascending liquor , does not help so much , to drive up the air to the mouth , as the water does . and the reason is , because the air , being more burdened with inches of mercury , than with inches of water , cannot so easily drive up the one as the other , and so mercury cannot so easily drive up the air of the pipe to the mouth , as water does . in a word , according to the difference of specifick weight , between water and mercury , so is the difficulty of suction ; therefore , because mercury is times heavier than water , there is times more difficulty , to pull up the one , than the other . note , that suction is not taken here strict●y , as contradistinguished from pulsion ; but in a large sense , as it may comprehend it . to proceed a little further , let us suppose the pillar of mercury ( see the . figure ) gh , that 's raised by the surface of air fg , to be inches , and every inch to weigh one ounce . secondly , that the said surface has degrees of power or force in it : for in all counterpoises the pondus and the potentia are equal ; therefore , if the mercury be inches , the potentia of the surface must have degrees of strength or force in it , to counterballance the pondus . these things being supposed , which are evident , let us imagine the surface of air , to raise the mercury one inch above fg. in this case , the surface is weaker than it was ; which i prove evidently , because it is now but able to raise of mercury . imagine next , the said surface to have raised the mercury two inches above fg , then it follows , that it must be yet weaker , because it 's now but able to raise inches : for by supporting two ounce of the pondus , it loseth two degrees of it's own potentia . in raising three inches of mercury , it is three degrees weaker ; and in raising four , it is four degrees weaker , and so forth ; therefore , having raised inches , there is but one degree of force remaining in the surface . and when it hath raised the whole , namely , it is no more able , and can no more press . for confirmation , put the case that the surface of air fg , were as able , and had as much pressure in it , after it hath raised inches of mercury , as it is after the raising of ; then it follows of necessity , that after the raising of , it shall raise moe , which is impossible , seing the greatest altitude is . it follows of necessity , ( i say ) because after the raising of , it is able to raise moe : therefore if it be as able after , as after , it must raise after . yea , if it be as able after as , it must be as able after as . if this be , then it may raise other , and a third , and so in infinitum . therefore , i conclude , that when two fluid bodies are in equilibrio one with another ; or when the pondus is equal to the potentia , none of them doth actually press upon another , at least the su●face hath lost all its power and pressure , which is also evident in the pillar . for understanding this , let us suppose acb ( figure . ) to be a pipe inches long , and full of mercury , and every inch of it to weigh one ounce . now , when the orifice d is opened , there is here as great an inequality , between the pondus and the potentia of the surface of air eb , on which it rests , as was between the surface fg , and the pondus of mercury hg . for as fg had degrees of power to raise gh , so the pillar ab has ounce of weight , to overcome the surface eb . and as the surface fg , became one degree weaker , by raising one inch of the mercury hg , and two degrees weaker , by raising two inches , and so forward , till it lost all its pressure ; so the pillar , by falling down one inch , loseth one ounce of the weight ; by falling down two , it loseth two ounce , and so forward , till by falling down from a to c , it loseth all its weight and pressure . but here occurreth a difficulty ; for if the surface fg , hath lost all its pressure , by raising the mercury from g to h ; and if the pillar cb , hath lost all its pressure , by falling down from a to c ; it follows , that when a pillar of a fluid , and a surface of a fluid are in equal termes , or b●ought to an equipondium , there is no pressure in them at all . for answer , consider first , that in all counterpoises , there a●e necessarily two things , the movens and the motum , the thing that moves , and the thing that is moved . secondly , you must consider the motum , to have a pondus or weight in it , and the movens to have a potentia , or power , wherewith it moves that weight . thirdly , that as the thing that moves , hath a power or force in it self , whereby it moves , so the thing that is moved hath a power or force in it self , whereby it resists the motion . fourthly , that sometimes the resistance of the thing moved , may exceed the power of the movent , as when a quarrier with a leaver , endeavours to prize up a stone too heavy for him : or the power of the movent , may exceed the resistance of the weight ; or both may be of equal power . consider fifthly , that as the pondus of the thing moved , begins to grow more and more , so the power of the movent decreaseth proportionably ; not absolutely , as heat is extinguished in water by the cold air , when it is removed from the fire , but respectively . for example , when a man holds a ballance in his hand , with six pound in the one scale , and but one pound in the other , if you add another pound , the weight grows more , and the power and force of the opposite scale grows less proportionably ; not absolutely , for it still remains six pound , but respectively : that 's to say , six pound is less in respect of four , than in respect of five ; or the resistance of six pound is less , two counterpoising it , than being counterpoised by one . when a third is added , the weight grows yet more , and consequently the resistance of the opposite scale becomes yet less , till by adding the sixth and last pound , you augment and encrease the pondus to that same degree of strength , that the resistance of the opposite scale is of . from these considerations , i say , the surface of air fg , hath not lost all its pressure absolutely , by raising the mercury from g to h , but only respectively , because it still retains degrees of force in it self . i say respectively , because when the mercury is raised ten inches , the power of the air which is of degrees of force , is less in respect of ten ounce , then in respect of five ; or the power of degrees of force is less , being counterpoised by ten ounce , than being counterpoised only by five . and when it is raised , it is yet less in this respect , than in respect of ten . and when it has raised the mercury to the greatest altitude h , it may be said to have lost all its pressure , seing it is not able , by vertue of a counterpoise , to do any more . even as six pound in this scale , may be said to have lost all its resistance and weight , by putting in the other scale , first one pound , next two pound , and then three pound , till the last be put in , at which time it hath no more resistance . though this be , yet it still remains six pound . even so , the air fg still remains of the same force and power , while it suspends the mercury gh , that it was of before . likewise , the pillar ab , cannot be said to have lost all its pressure absolutely , by falling down from a to c , but only respectively , because the said pillar cb , is still ounce weight . i say respectively , because in falling down ten inches , or in losing ten ounce , the weight that 's now but , is less , in respect of , than while it was . it is yet less , when it hath fallen down other ten , because being now but , it must be yet less in respect of , than . and when it hath fallen down to c , it may be said to have lost all its weight , because it can do no more , having respectively lost all its pressure . from what is said , we see a clear ground to distinguish in fluids a pondus and a potentia . secondly , that the potentia may sometimes exceed the pondus , and contrariwise the pondus may exceed the potentia . thirdly , that inequality of weight , between the pondus and the potentia , is the cause of motion of fluids . fourthly , that the motion never ceaseth , till the pondus and the potentia become of equal force . this conclusion is not so universal as the rest , because the motion may sometimes cease , before this be . for example , when the air is pressing mercury up thorow a tub shorter then inches , the motion ends before there be a perfect counterpoise ; for or inches of mercury , can never counterballance the force and power of the air. in such a case then , there is an unequal pressure , the air pressing the mercury more , than the mercury doth the air. experiment viii . figure . take the vessel abcd , and fill it with water , as high as hi . take next a cylinder of stone fg , and drowning the half of it among the water , suspend it with a chord to the beam no , with a ring at e. now in this case , though the stone do not touch the bottom of the vessel , yet the water becomes heavier , than before . for discovering the true reason of this , i suppose fi●st , the weight of the water , before the stone be drowned , to be pound . i suppose next , that after the stone is drowned , the said water to weigh pound . and lastly , the stone to weigh pound . i say then , the water must be pound heavier than before , because it supports pound of the stone . 't is certain the beam is less burdened by pound than before . if this be , then surely the water must sustain it . it were great temerity and rashness , to averr that neither the beam , nor the water sustains it , which is really to say , it is sustained by nothing . it cannot be said without ignorance , that pound of the stone is evanished , and turned into a chimera . if it be said , how can such a fluid body as water , be able to support any part of the weight of the stone , that is such a heavy body ? i answer , there is here no difficulty , for if the imaginary surface kl , upon which the pound of the stone rests , be able to sustain pound of water ( i suppose the stone taken away , and the place of it filled with water ) then surely it must also be able to sustain pound of the heaviest metal ; seing ten pound of lead , or gold , or stone , is no heavier than pound of vvater . if some say , this rather seems to be the reason , why the water becomes heavier , after the stone is drowned , because it possesseth the place of as much water , as would weigh pound ; not ( as was said ) because the vvater supports pound of it . therefore it may be judged , and thought , that if the space that the stone occupies , were filled with air , or some light body , without sensible weight , the vvater would become heavier than before . for example , if in stead of the stone , there were placed a bladder full of wind , within the vvater , and tied to the bottom with a string , that the surface might swell from hi to ab , the vvater of the vessel would become as much heavier than before , as is the bulk of vvater , equal to the quantity of the bladder . therefore , the vvater becomes heavier , not because it supports any part of the stone , but because the stone occupies as much room and space , as would contain pound of vvater : for by this means the drowned stone raiseth the vvater from hi to ab ; and so the cylinders ac , and bd , being higher , press with greater weight upon the bottom cd , even with as much more weight , as if the space that the stone occupies were filled with vvater . for answer to this , we shall make this following experiment . take the vessel mpvx , and fill it with vvater to qr . next , take a large bladder wy full of wind , and tying the neck with a threed , thrust it below the water , and fasten it to the bottom , with a string , to the ring z. this done , the water swells , and rises from qr , to mp . now , if it be true , that the water in the vessel becomes heavier , not because it supports pound weight of the stone , but because the stone occupies the room of pound of water ; then it ought to follow , that after the bladder is tyed below the water , the said water should become heavier , than before , even by three pound ; for i suppose a bulk of water , equal to the bulk of the bladder , to weigh as much . and the reason is , because ( as you say ) the quantity of the bladder wy , makes the water swell from qr to mp , by which means the pillars of water mv , and px becomes higher , and so presseth with greater weight upon the bottom vx . for clearing this difficulty , i say , when a bladder is thus below the vvater , tyed to the bottom , the vvater becomes not three pound heavier : for when you place the vessel with the vvater and bladder , in the scale of a ballance , the said vvater weighs no more , than if it wanted the bladder : therefore the vvater becomes not heavier , because the stone possesseth the room of pound of water , but because the water sustains pound of the stone . now the reason , why the bladder makes not the water heavier , though it raise it from qr to mp , is this ; because though verily there be a greater pressure then before , even upon the bottom of the vessel , yet because moe parts are not added , the natural weight cannot be augmented , which essentially depends upon the addition of these parts . if it be replyed , the experiment of the bladder is to no purpose , because it being knit to the bottom , pulls up the vessel , with as great force , as the growth of the pressure bears it down , and so the bladder cannot make the water heavier . but , if so be , it were possible , that the bladder could remaine within the middle of the water , without being knit to the bottom , and consequently without pulling up the vessel , then surely the pillars of water mv , and px , being higher , would press with greater weight upon the bottom , and so make the vessel , and the water weigh more in the ballance : for 't is to be supposed , that during all this time , this vessel with the water , is in one scale , and a great weight of stone or lead , in the other . so would the water abcd become heavier likewise , provided the space and room , that the stone fills among the water , remained intire , after the stone is taken away : because that room and empty space remaining , would keep the surface , as high as ab , by which means , the pillars ac and bd , being higher , would press with greater weight upon the bottom , and cause the water weigh more in the ballance . i answer , though by some extraordinary power , the bladder could remain below the water , of its own accord , as it were , and though the space and room , by that same power , which is left by the stone , were keeped empty , yet shall they never be able to make the water heavier . as to the reason , that 's brought , i answer , the rising and swelling of the pillars , will make indeed a greater pressure upon the bottom of the vessel , but because this pressure may be produced , and generated without the addition of new parts , therefore , it can never make the water heavier : for if this were true , then it would follow , that the more a body is comprest , it should be the heavier , which is contrary to sense , and experience . this pressure is like unto bensil , that cannot weigh in a ballance , though the thing bended do weigh ; as a bow that weighs so many pounds , but the bensil of it weighs nothing : next , will any man think , that a cub of water six foot high , and six foot thick , will weigh more in a ballance , then it did , after it is turned into a long square pillar inches high ? i grant , there is near times a greater pressure , upon the bottom of the vessel , yet because this pressure is generated , without the addition of new parts , it cannot make the water heavier . moreover , it is mechanically possible to keep the vvater stvx , under that same degree of pressure it hath , though the rest above were taken away : if this be , then it ought to be as heavy , as the whole , seing it still presses the bottom , with that same degree of pressure , it had from the whole : but what is more absurd , than to say , one part of vvater , is as heavy , as the whole ? e. g. a pint as heavy as a gallon . if it be said , the pressure , and the weight , are but one thing , at least effectively , which is sufficient to the purpose in hand , as is clear from the theorem . i answer , they are but one thing indeed , in order to the ballance of nature , but they are neither formally , nor effectively the same thing in order to the libra or artificial ballance , whereof we are now treating . i shall conclude with this ; while the vessel with the vvater , is thus placed in the scale of the ballance , and in equilibrio , with the opposite scale , cut the string that tyes the bladder to the bottom , and when it comes above , you will find the vvater , just of the same weight it was of : for though the surface mp , by taking out the bladder , settle down to qr , yet there 's no alteration made in the weight . from this i gather , that if the swelling of the vvater should make it heavier , then the subsiding and falling down of it , ought to make it lighter . from these experiments we gather first , that in vvater there is a pressure , because it sustains pound of the stone fg. secondly , that whatever heavy body is weighed in water , it loseth just as much of its weight , as the bulk of water weighs , it puts out of its place . this is evident , because the stone is pound lighter in vvater , than in the air , because the vvater that would fill the room of the stone , is just of that weight . vve see thirdly , that the pressure of vvater , and the natural weight of it , are two things really distinct ; because the pressure may be augmented , without any increment of the natural weight . vve see fourthly , that the pressure , or bensil of a fluid , cannot affect the scale of a ballance , but only the natural weight . vve see fifthly , that a body naturally heavier than water , weighs in water , because the stone fg , makes the water about it , pound heavier . if it be inquired , whether bodies , that are naturally lighter , will weigh in water ? i answer , if they be of any sensible weight , they weigh , as well as the other . for this cause , i except air. for though they were never so light , in respect of water , yet if they have any considerable gravity with them , they will make the water heavier , they are among . put the case the body were a cube of timber of six inches , weighing sixteen ounces , and that a cube of water of that quantity , weighed ounces . here 's a great inequality , between their natural weights : yet if that piece of timber , were made to exist in the middle of water , as the bladder doth , it would make it ounces heavier . the reason is this ; these ounces are either supported by a surface of water , or they support themselves . this last is impossible . if the vvater support them , then must they make the said vvater ounces heavier . note , that though a body naturally lighter then vvater , as cork , may be said to weigh in water , that 's to say , to make it heavier , in which sense vvater weighs in water , because if you add a pint to a gallon , it makes it heavier ; yet if you take a piece of cork , and knit it to the scale of a ballance , by a threed , the cork hanging among the vvater , the scale hanging above in the air , it will not weigh in water ; because in this sense , no body weighs in water , but that which is naturally heavier then vvater , as lead , or stone . in this sense , vvater doth not weigh in water , as will be seen in the experiment . experiment ix . figure . take a glass-pipe inches long or there-about , and of any wideness , having the upper end h , hermetically sealed , the lower end c compleatly open , and fill it with mercury , and cause a diver carry it down to the ground of the sea mn , where i suppose is standing the vessel abde with stagnant mercury , and drown the end below the surface ab . this being done , the mercury falls from the upper end h , to the point g , and there halts ; the space hg being empty . for understanding this experiment , i shall propose several questions , and answere them . first , what 's the reason , why the mercury subsides , and sinks down from h to g ? i answer , as formerly in the like cases , inequality of weight between the pondus of the impending quick-silver , and the potentia of the surface , of the stagnant quick-silver dce . for while the tub is compleatly full , the weight is so great , that the surface dce , is not able to sustain it , therefore it must fall down , seing motion necessarily followes in fluids , upon inequality of weight . it may be inquired secondly , why it halts at g , inches from ab , and comes no further down ? i answer it halts at g , because when it hath fallen down to that point , there happens equality of weight , between the suspended pillar , and the foresaid surface : for whatever weight the said pillar is of , the surface on which it rests , is of the same . in a word , the pondus of the one , and the potentia of the other are now equal . for understanding this , consider according to the theorem , that the weight of the element of air , upon the surfaces of waters , is equivalent to the burden of foot of water , therefore the first and visible surface of this water lik , is really as much prest , with the burden of the atmosphere , as if it had foot of water upon it . consider next , that between the said surface , and the ground mn , are foot of water indeed . consider thirdly , that a pillar of water foot high , is exactly of the same weight , with a pillar of mercury inches high ▪ for if water be times lighter than mercury , then they cannot be of equal weight , unless the one be times higher than the other . now , supposing the weight of the air upon the surface lik , to be equivalent to foot of water , or ( which is the same thing ) to inches of mercury , the surface of the stagnant mercury ab , must be as much burdened with the incumbing water , and the air together , as if it had really resting upon it , a pillar of mercury inches high . if this be , then it follows by necessity , that there must be an equality of weight , between the pondus of the mercury in the tub , and the potentia of the surface dce ; or ( which is all one thing ) that the part c , on which the pillar rests , is no more burdened , than the part d or e. for if foot of water , and foot of vvater , be equivalent for weight , to inches of mercury , then must the part d and e , be as much burdened with the said weight , as the part c is burdened with the pillar within the tub , seing both are of the same height : therefore the power , and force of the imaginary surface of the stagnant mercury dce , is of the same strength , with the weight of the pillar gfb . and this lets us see the reason , why the whole inches cannot be suspended ; for if the outward pressure that 's upon ab , be but equivalent to the pressure of , it can never make the surface dce able to support . to make it evident ( if any doubt ) that the mercury is suspended by the weight of the water , and the weight of the air superadded , let a diver bring up this engine to the top of the water , and he will find the one half to have fallen down , namely from g to f , the other half fb remaining . and if it were possible , to convey this experiment to the top of the air , the bearer would see , the remaining half to fall down likewise , and become level with ab ; for where no pressure of air is , there can be no mercury suspended . this falling down , is not all at once , but by degrees , and keeps a proportion with the pressure of the air , that grows less and less , from the ground to the top . from this experiment we see first , the great pressure and weight , the elements of air and water are under , seing this water , that 's but foot deep , sustains the mercury between g and f , inches , as much between f and e , being kept up by the pressure of the air. we see secondly , that this pressure is according to arithmetical progression , as , , , , . because in going down the first inches , the mercury rises one inch ; in going down the second inches , it rises two ; in going down the third inches , it rises three , and so forward . we see thirdly , though a vvater were fathom deep , yea , yet the pressure of the air above is found at the bottom : for supposing this experiment were fathom deep , yet would the air from above have influence upon it , to sustain so many inches of the mercurial cylinder . a diver then , or fathom under the vvater , must be burdened with the weight of the air , as well as with the weight of the vvater , so must the fishes , though never so deep . we see fourthly , that the parts of a fluid cannot cease from motion , so long as there is an inequality of weight between the pondus and the potentia . this is clear from the falling down of the mercury from h to g. and assoon as equality of weight happens , the motion ends . this is clear from the mercurie's halting at g. fifthly , that in mercury , as well as in water , or air , surfaces may be distinguished , and that these surfaces , are endowed with a potentia or power , begotten in them by superior and extrinsick weight . this is clear from the imaginary surface dce , that 's made powerful to support inches of mercury in the tub , and that by the weight and pressure of the air resting upon ab . sixthly , that , as two fluids differ in specifick and natural weight , so they differ in altitude , when they counterpoise one another . this is clear from the disproportion that 's between the altitude of the mercury suspended , and the height of the water , and air suspending . gf then is inches , and the deepness of the water from k to n is foot , because water is naturally times lighter than mercury . fb is likewise inches , and the hight of the air , that rests upon the surface of water is six or seven thousand fathom high ; because air is times naturally lighter than mercury . seventhly , that fluid bodies counterpoise one another , not according to their thickness and breadth , but only according to their altitude . this is evident ; for though this tub were never so wide or narrow , yet the altitude of the mercury is unchangeable . hence it is , that the thickest pillar of water in the ocean , is not able to suspend more mercury , than the slenderest , i mean as to altitude . and hence it is , that the smallest cylinder of mercury , no thicker than a silk threed , is able to counterpoise a pillar of water , of any thickness whatsoever . we may conclude lastly , that when a diver is fathom under the water , he is under as much burden , as if he were under or foot of quick-silver . suppose a man lying on his belly , within a large vessel , and or foot of mercury poured in upon him , surely it may be thought , that such a burden were insupportable . but put the case , the diver were down fathom , then must the burden be doubled . this follows , because if a pillar of water foot high , with the weight of the air superadded , be as heavy , as inches of mercury , then surely a pillar fathom high , or foot , must be as heavy as inches , which is more than foot . experiment x. figure . against the former experiment , there occurres some difficulties , which must be answered . as first , if it be the pressure of the water , that sustains the mercury in the tub ( see the . figure ) then the weight of the said mercury ought not to be found , while the tub is poised between a mans fingers . but so it is , that when a diver grips the tub about the middle , and raises it a little from the bottom of the vessel , he not only finds the weight of the tub it self , but the weight also of the inches of mercury that 's within it . but this ought not to be , if the said mercury , be sustained by the outward water . in a word , it ought not to be found , because the said pillar of mercury , as really stands , and rests upon the imaginary surface dce , as a cylinder of brass or stone , rests upon a plain table of timber or stone . if then , it be supported by the said surface , why ought i to find the weight of it , when i lift up the pipe a little from the bottom of the vessel ? for clearing this difficulty , consider , that when the mercury falls down from h to g , it leaves a sort of vacuity behind it , wherein there is neither air nor water . consider secondly , that for this cause , there happens an unequal pressure ; the top of the tub without , being burdened with the pillar of water ih , which actually presseth it down , and nothing within between g and h , that may counterballance that downward pressure . these things being considered , i answer to the difficulty and say , it is not the weight of the suspended mercury that i find , but the weight of the pillar of water ih , that rests upon on the top of the tub. if it be said , the pressure of a fluid is insensible , and cannot be found . i answer , it 's true , when the pressure is equal and uniform , but not when the pressure is unequal , as here . if it be asked , how comes it to pass , that the pillar of water ih , is exactly the weight of the inches of mercury ? i answer , besides the said pillar , there is another of air , that rests upon the top of it , which two together are exactly the weight of the suspended mercury ; ih being of the same weight with the mercury gf , and the foresaid pillar of air , being of the same weight with the mercury fb . to make it more evident , remember that one inch of mercury , is exactly the weight of inches of water ; and that one inch of mercury , is of the same weight with inches of air. if this be , then must the pillar of vvater ih , that 's foot high , and of the same thickness with the inches of mercury gf , be of the same weight with it , seing inches are to be found times in foot . for the same reason , is the pillar of air , namely si , that rests upon the top of the pillar of vvater ih , of the same weight with the inches of mercury fb . for after a just reckoning , you will find , that inches will be found times in the pillar of air , that rests upon the pillar ih . or in a word , the hight of the air is times , inches . but here occurrs another difficulty . let us suppose there were a tub six foot high , one inch wide , having the sides , inches thick . imagine likewise the said tub to be under the water foot , with inches of mercury in it , as is represented in this figure . this being supposed , the pillar of water eafcgd , must be far heavier , than the inches of mercury hb . the reason is clear , because the said pillar , is not only foot high , but as thick , as the diameter of the tub , whose sides are three inches thick . i answer , the whole weight of that water eafcgd is not found , while a man poises the tub between his fingers , but only the weight of the part ga , which is exactly the weight of the mercury hb . but here occurrs the great question , namely , why i find only the weight of the water ga , and nothing of the weight of the water , ce , or de ? i answer , i cannot find the pressure of the water ce , because it is counterpoised with the upward pressure of the water ik . and for the same reason , i cannot find the weight of the water df , because it is counterpoised by lm ; but because there is nothing between h and a , to counterpoise the downward pressure of the water ga , therefore i find that . if it be objected , that the water ik , cannot counterpoise the water ce , because the one is farder down than the other , and consequently under a greater pressure , than the other . i answer , though ik be stronger than ce , yet a compensation is made by the weight of the tub. for understanding this , let us suppose the water ce , and df , to press downward with the weight of six pound , and the water ki , and lm , to press upward with the weight of ten pound , there being four pound in difference . suppose next , the tub to weigh in the air ten pound , and in the water only six pound . if this be , then according to the eighth experiment , and eighteenth theorem , four pound weight of the tub must rest upon the surface il. and if this be , then must the water ik , and lm , be four pound weaker with the tub , than without it , and must only have six pound of upward pressure . fig. pag. ● fig. fig. ● pag. ● fig. pag. fig. pag. experiment xi . figure . amzc is a water foot deep . ab a glass-tub inches long , and full of mercury . bc a pillar of water foot , inches high , thorow whose middle goes a string to the scale of the ballance k , existing in the air. de is a tub full of mercury inches long , with a pillar of water above it ef , foot and eight inches . gh a tub inches long , with a pillar of water above it hi , foot and six inches high . and lastly , adgsm an imaginary surface , foot deep . this experiment is brought hither , to demonstrate that a heavy body , weighs as much in water , as in air , which is point-blank to the common received opinion , and destructive of the theorem . to evince this , i must suppose the inches of mercury in the tub ab to weigh ounce ; and the inches of mercury de , to weigh ounce ; the inches gh to weigh ( i mean in the air ) ounce . now i say , to make a just equipondium between the two scales k and l , there must be ounce put into the scale l. if after this manner you weigh the tub and mercury de , ounces will be required in the scale l , and , if you weigh the tub and mercury gh . for proving this doctrine , i must appeal to experience , which will not fail in this . if you reply , and say , upon supposition the tub and mercury gh , were a solid piece of brass , or iron thus suspended in the water , ought it not to weigh less here than in the air , even as much less , as is the weight of the quantity of water , it puts out of its place : why then should not the pipe hg , with the mercury in it , do the same , seing there is no apparent difference between them , as to this ? but to leave this , which will appear afterwards , and to let the reader see the truth of the theorem , i affirm , 't is not the weight of the ounces of mercury ab , that burdens the scale of the ballance k , and that makes a counterpoise with the ounces of stone , or lead , that 's in the scale l. what then is it , you say ? i answer , 't is ounces of the pillar of water bc that does this . neither doth the weight of the ounces of mercury de burden the ballance , but only ounces of the water ef. neither doth the ballance support the weight of the ounces of mercury gh , but it is only burdened with ounces of the water hi . the reason is most evident , because according to the principles of the hydrostaticks already laid down , the cylinder of mercury ab , within the tub ab , rests immediatly upon the imaginary surface of the water adg , and therefore cannot burden the scale in any wise . the same is true of the other two cylinders of mercury . but in this i find small difficulty . the greater is , how to make it out , that the scale k , supports ounces of the water bc , and of the water ef , and of the water hi . to make this seem probable , consider first , as was noted , that this vvater is foot deep , and consequently the pillar of vvater bc , foot inches . the vvater ef foot eight inches . and hi , foot and a half . consider secondly , though this be true , yet we must count the pillar of vvater zm foot high . the reason is evident , because the pressure of the air , upon the surface of all waters ( according to the theorem ) is equivalent to foot of water : this then being added to , makes , and by this reckoning the water bc is foot ten inches : the water ef foot eight inches : and lastly , the water hi foot six inches . thirdly , for easie counting , i must suppose the whole cylinder zm to weigh ounces , every inches one ounce : and consequently the water bc to weigh ounces ; the water ef to weigh ounces ; the water hi ounces . note , that in physical demonstrations , 't is not needful to use mathematical strictness in counting ; and so leaving out fractions , we shall onely use round numbers ▪ consider fourthly , that in all fluids , as hath been frequently marked , there is a pondus and potentia , the water bc being the pondus , and the mercury ab the potentia , the one striving to press down the tub , the other striving to press it up . consider fifthly , that by how much the more a body suspended in a fluid is pressed up , by so much the less the weight that presseth it down is found : and contrariwise , by how much the less it is pressed up , by so much the more the pressure above is found . consider sixthly , the less that a surface of water is burdened , the more able it is counterballance the opposite pressure , and the more it is burdened , it is the less able . consider seventhly , that the mercury ab , ( which is evident in all fluids ) not only presseth downward , and burdens the surface adg , but also presseth upward , and therefore actually endeavours to thrust up the tub ; and so it is , that the tub is pressed between two , namely between the water cb , and the mercury within it . now from these considerations i say , the scale k , must support , and bear up ounce of the water bc : for seing the mercury is supported by the surface of vvater on which it rests , it cannot by any means burden the ballance with its weight ; and seing it actually presseth up the tub , ( according to the seventh consideration ) it must so much the more counterpoise ( according to the sixth ) the opposite pressure of the vvater bc , and consequently diminish the weight of it : so that the ballance cannot support the whole , but a part . for according to what degrees of force , the mercury presseth up the tub with , according to the same , must the pressure upon the top of the tub be diminished , and so if the mercury press up the tub with the force of ounce , the vvater bc must press it down with ounce only , and so the cylinder bc , that weighs really ounce , must press the top of this tub only with , which ounce really counterpoiseth , the ounce of stone in the scale l. but how is it made out , that the mercury ab , presseth up with ounce ? for understanding this , remember , that the vvater is foot high , taking in the pressure of the air , and that a vvater of that deepness is able to support inches of mercury , every inch weighing one ounce . for if of water , be able to support one of mercury , foot , or inches , must support . if then , the part of the surface a , be able to weigh , it must have of upward pressure ounces , seing it's counterpoised de facto only with . take notice , that in the hydrostaticks , the word pressing , or weighing , as really and truly signifies a weighing up , as a weighing down , seing it is no less essential to fluid bodies to move upward , than downward , and that with equal force , and weight . according to this reasoning , the ballance supports ounces of the water ef , ( imagine the second tub to be suspended as the first ) seing the cylinder of mercury de , presseth up the tub only with the weight of ounce , which ounce , really counterpoiseth the ounce of stone in the scale l. but why doth the mercury ab press up with ounce , and the mercury de with ? for answer , remember , ( according to the sixth consideration ) the shorter a cylinder of mercury is , the surface upon which it rests , is the stronger , and more able to press it up ; and contrariwise , the longer it is , the surface is the more unable and weak : therefore ab being shorter , and lighter than de , the surface of water must press it up with greater force : so that if the said surface am , be able to press up the mercury ab with ounce , it must press up the mercury de only with ounce . according to this rule , if the mercury ab were inches high , it would press up only with ounce , if it were , with : if , with : if , with , and so forward . this leads us to a clear discovery of all the secrets here : for if the mercury ab , thrust up the pipe , with the weight of ounce , then must the scale k , be eased of so much weight , and so much must be subtracted from l. now let us imagine the pipe ab , to be empty both of air , water , and mercury : in this case ounce must be in the scale l , to counterpoise it , seing the whole cylinder bc , that weighs so much , does now really counterpoise it . let us imagine next , these inches of mercury to rise , and fill the tub ab : in this case , there happens a great alteration ; because the rising of them , are really equivalent to the subtracting of ounce from the scale l ; and the reason is , because by so rising and filling the tub , they thrust up the said tub , and by this means easeth the scale k , of so much weight . now this scale being eased , you must of necessity take out from l ounce for making a new counterpoise . and lastly , the scale k must support the whole weight of the water hi , which is ounce , nothing remaining to counterballance this downward pressure , and consequently to ease the ballance . how then is it counterpoised ? for clearing this , you must remember that this water , that 's really foot deep , must be reckoned ( as i said ) , because of the pressure of the air upon the top , that 's equivalent to . if then it be so , it cannot raise mercury higher in a tub than inches ; the one being times heavier than the other : so that if inches of water , cannot raise mercury higher than one inch , foot cannot raise it higher , than inches : for as inches , are to one inch ; so is foot to three foot and an half , which is inches . now i say , the whole weight of the water hi , rests upon the top of the tub , and so presseth down the scale k , to which you must imagine this tub , knit by a string , as the former was , nothing remaining to counterpoise this downward pressure : for the top of the mercurial cylinder being raised as high within the pipe , as the surface of water dgs , is able to raise it , the said top can impress no force upon the tub within , to thrust it up , and so to ease the scale k. for example , when a man erects upon his hand a cylinder of timber , or any such like thing , which is the outmost he can support , he will not be able to impress any impulse , upon the seiling of a room above his head ; but if so be , in stead of that taken away , there be one lighter erected , which he is able to command , he can easily thrust up the seiling at his pleasure . just so it is here ; for the inches of mercury , being the outmost , that the surface of water dgs is able to bear , it cannot impress any impulse therewith upon the top of the tub within : but easily can the cylinder de impress an impulse , and more easily the cylinder ab , seing they are lighter , and so more powerful . to evidence this a little more , let us imagine two things , first , the tub gh to be empty , as if vacuity were in it . in this case the top of the tub ought to bear the whole burden of the water , and consequently the ballance to bear it also : because there is not a potentia within the tub , to counterpoise this pondus . next , let us imagine the tub to be only full of water : according to this supposition , the ballance cannot be in the least part burdened ; because the water within the pipe , presseth it up with as much force , as the water ih presseth it down : and if any thing should burden the ballance , it would be only the weight of the pipe , that 's not considerable . from what is demonstrated , we see first , that though this experiment would seem to prove at the first , that a heavy body weighs as much in the water , as it doth in the air , because the whole weight of the mercury ab is found in the scale l , yet 't is not so , because the ounce of stone l , doth not counterpoise any of the mercury ab , but ounce of the pillar of water bc. secondly , there 's here a clear ground , for asserting a pondus and a potentia in fluids ; because this tub ab , is prest down with the vvater bc , and prest up with the mercury within it . thirdly , there 's here a clear ground for asserting the pressure of vvater , even in its own place ; because the water bc , counterpoises by it's weight , the ounce of stone l. fourthly , we see an excellent way for finding the weight of any cylinder of water ; for whatever be the weight of the mercury in the tub , the cylinder of water , that rests upon the top , will be of the same weight exactly ; this is evident in comparing the weight of the mercury gh , with the weight of the water hi . fifthly , that whatever be the height , and weight of a pillar of water , yet the ballance can sustain no more of it , than the just weight of the mercury : this is also evident , because the scale of the ballance , supports no more of the weight of the water bc , than the just weight of the mercury ab . we see sixthly , the further down a pipe with mercury goes through water , the greater is the pressure it makes upon the top of the tub within : for put the case , this were foot deep , the mercury gh , that wants all upward pressure now , would press up the tub with ounce : the mercury de with , and the mercury ab with . we see seventhly , the shorter a cylinder of mercury be , it is the stronger in pressing ; and longer it be , it is the weaker ; for there 's more strength in ab , than in de. we see eighthly , that the strength decayes , and grows , according to arithmetical progression , as , , , ; because if you make the cylinder gh , that 's now , it presseth up with one ounce . make it inches , it will press up with two ounces of weight . make it , it presseth up with three . and contrariwise , make the cylinder de inches , that 's now but , it will press up with ounce only . ( vvith it presseth up with . ) make it inches high , it will press up with . if it be inches , it presseth up with nine , and so forward . lastly , make the cylinder ab inches , that 's now but , it presseth up with ( with , it presseth up with ) make it , it presseth up with ; make it , it presseth up with . we see ninthly , that in fluids , we may make a distinction between a sustentation , and an equipondium . 't is evident here , because there 's a perfect equipondium between the inches of mercury gh , and the outward water that 's foot deep . but 't is not so , between the said water , and the mercury de ; because the said water is able to raise the said mercury inches higher : therefore the water only sustains the mercury de , but counterballances the mercury gh . we see tenthly , that the pondus of the pillar of water bc is counterpoised by two distinct powers really . the one is the ounce of stone in the scale l , the other is the inches of mercury ab , that as really thrusts up the water , as the scale k pulls it up , by vertue of the opposite weight . eleventhly , take away the stone l , and you will find the pipe with the mercury ab sink down : this happens , not because the surface of water on which it rests is not able to sustain it , but because the ounce of the water bc , that was supported by the stone , doth now press it down . twelfthly , the more a body is unequally pressed by a fluid , the more of the weight of that fluid is sensible ; and the more equally a body is pressed , the less sensible is the weight of that fluid : this is evident , because there 's a greater weight of the vvater hi found in the ballance ( it takes ounce to counterpoise it ) than of the vvater ef , which is counterpoised with ounce : and the reason is , because the top of the tub h , supports the whole ounce of vvater hi , the mercury within the tub , not being able in the least to counterpoise it , or thrust it up . but because the tub de , is more equally pressed ( the vvater ef presseth down with , and the mercury de presseth up with ) therefore less weight of the vvater ef burdens the ballance , only ounce . hence it is , that because the tub ab , is more equally pressed , than either de or gh , there 's less of the weight of the vvater bc , found in the ballance , only ounce . thirteenthly , if in the instant of time , while the tubs are thus suspended in the vvater , the pressure of the air above were taken away , and annihilated ; then first , the inches of mercury gh would fall down , to about inches . secondly , the inches of mercury de , would fall down to as many . and lastly , the ab , would sink down to the same height . the reason is , because the pressure of the air being equivalent to foot of vvater , no more would remain but foot , which is the real height , according to zm . but foot of water , cannot sustain moe inches of mercury than about . and consequently , first , ounce of stone in the ballance , would counterpoise the whole water bc. the reason is , because the water bc is but of ounce ; and the mercury ab , being but inches high , could impress no impulse upon the top of the tub within , that 's inches high . secondly , ounce of stone in the scale l , would counterpoise the whole water ef , seing ef is but ounce . thirdly , the same weight ( one ounce being deduced ) would counterpoise the water hi , because in this case , it weighs but ounce , to proceed a little further , imagine the pipe gh to be suspended by the ballance , as the pipe ab is ; and then a little hole opened in the top h , to suffer the water to come in , till the mercury subside inches , namely from q to o ( imagine this tub to be the other ) and then stop it . the reason why the vvater rusheth in , and presseth down the mercury , is the force and pressure of it : for the said vvater , finding the cylinder in equilibrio with the outward vvater , presently by its own weight , casts the scales , which is easily done , seeing the surface gsm supports as much burden as it can . but that which is more considerable is this ; after the subsiding of the mercury from q to o ; the equilibrium that was between the scale of the ballance , and the vvater qr is destroyed : for whereas ounces were required before ; will now do it . for understanding the reason of this , consider that between q and o , are inches of vvater rushed in , which are equivalent to one inch of mercury . next , according to former reasonings , the ballance must support ounces of the vvater qr ; because in this case , the top of the pipe within , is pressed up with the weight of ounces ; which in effect , diminisheth as much of the downward pressure of the vvater rq , which before had the burden of ounces . but why is the tub prest up with ounces ? i answer , because the mercury , that before was inches , is now but ▪ or having the inches of water qo above it , it is , therefore being shorter , the surface gsm is the more able to press it up , even with as much more force , as it is in inches shorter . in the second place , let in as much water more , as will depress the mercury other inches , namely from o to p. in this case , ounce of stone will make an equipondium ; because , the inches of mercury ps , and the inches of water poq , being a far lighter burden by , than the ● inches of mercury , the surface gsm must be far abler to press them up now , than before : and therefore , must diminish as much of the downward pressure of the vvater qr , that burdens the ballance , as themselves wants of weight : seing then , the whole cylinder of mercury , and water together , are but equivalent for weight to inches of mercury , the top of the tub within , must be prest up with ounce ; and therefore they by their upward pressure , must diminish ounce of the weight of the water rq , that weighs . lastly , let in so much vvater , as will depress the last inches ps ; and you will find no more weight required in the ballance to make an equipondium , than counterpoiseth the simple weight of the tub , which is not considerable . the reason is , because , the part s , of the surface gsm , being liberated of the burden of mercury , and sustaining only the vvater within the tub , instead of it , this surface presseth up the vvater within the tub , and consequently the top of it , with as great force , and w●ight , as the top of the tub without is depressed , with the outward vvater rq : therefore , ounce depressing the tub , and ounce pressing it up , the ballance must be freed of the whole weight of vvater rq . if it be objected , that the inches of vvater qs , are equivalent in weight to three inches of mercury ; therefore the part of the surface s , being burdened with this , cannot press up , with as great force , as the vvater rq presseth down . for answer , consider , that the part s , is able to support ounce of vvater , and next , that the vvater rq weighs but . then i say , seing the inches of vvater within the tub , weighs only three ounce , the part s , that 's burdened therewith , being able to support , it must press up with the weight of , and so counterballance the vvater rq . if it be inquired , whether or not , would the inches of mercury ab fall down , a small hole being made in the top of the tub at b ? i answer , they would . if it be objected , that these inches of mercury , are not in equilibrio , with the pressure of the ambient water , as the mercury gh , and therefore they cannot be so easily depressed by the water , that comes in at the said hole . i answer , they must all fall down , and as easily , as the other , and that because of inequality of weight between the potentia of the surface of vvater , and the pondus . it 's certain , the part a of the surface , cannot support more weight of any kind , than ounce ; but when a hole is opened in b , and the vvater comes in , 't is then burdened with the weight of ounce of mercury , and with the weight of ounce of vvater ; so much the vvater bc weighs , which is ounce : but a surface that hath only the potentia of , can never support a pondus of , no not of . it may be objected thus : put the case a cylinder of gold , or brass were suspended in this vvater ; as the pipe and mercury gh are suspended by the ballance , would not the ballance support the whole weight of it , without supporting any part of the weight of the vvater ih , that rests upon the top of it . i answer , there 's a great difference between the two ; because a cylinder of gold or brass , suffers both the upward and downward pressure of the vvater ; but the mercury gh , suffers only the upward pressure , being freed of the downward , by the top of the tub. from this experiment of letting in the vvater upon the top of the mercury , we see first , that when two fluids are in equilibrio one with another , a very small weight will cast and turn the scales , because , if the sixth part of an inch of vvater come in at q , it presently alters the hight of the mercury from inches to less . secondly , 't is impossible for a surface of water , to support more weight , than its own proper burden ; because the part s , cannot support more , no not a grain , than ounce . vve see thirdly , that it is as impossible for a surface of vvater , to support less , than its own burden ; because whatever loss of weight the pillar of mercury sq suffers , by the ingress of the vvater qo , it s made up again by the same vvater . if it be objected , that the inches of vvater qo , are not so heavy by far , as the inches of mercury , that fell down . i answer , its true , yet the part s , is as much burdened as before , because what is wanting in weight , it s made up , and compensed by pressure . vve see fourthly , that the pressure of a fluid is a thing really distinct from the natural weight , according to the theorem : because though the inches of water qo , are not so heavy naturally as the inches of mercury that fell down , yet the pressure of them upon the surface s , is as much . we see fifthly , that inches of water , that 's a body fourteen times lighter than mercury , may have as much weight with them , as ounce of mercury . we see sixthly , that a cylinder of mercury cannot be suspended in air , or in water unless it be guarded with a tub , to preserve it from the downward pressure of that air or water : for by opening an hole in q , the mercury subsides . we see seventhly , that 't is impossible for two fluids to suspend one another mutually , unless there be a sort of equipondium between them ; because no sooner you destroy the equipondium , between the inches of mercury qs , and the part of the surface s , by the ingress of the water qo , but assoon there ariseth a new one . we see eighthly ( as we noted before ) the nearer a body comes to be equally pressed with a fluid , the less is the pressure of that fluid sensible : because less weight is required in the ballance , to counterpoise the pressure , and weight of the water rq , after the ingress of the water qop , than after the ingress of the water qo . we see ninthly , that when a body is equally , and uniformly pressed with a fluid , the pressure is insensible ; because , after the water hath thrust down all the mercury from q to s , there 's no more weight at all of the water rq found in the ballance . we see tenthly , that not only in water , the pressure of water may be found , but out of it , namely in the air ; as is clear from the ballance , that supports the pressure of the water rq . we see eleventhly , a ground to distinguish between the natural ballance , and the artificial ballance . the artificial ballance , is the ballance kl : the natural , is the pipe qs . we see twelfthly , that they keep a correspondence between themselves , or some analogy : for by what proportion the water thrusts down the mercury , by that same proportion the pondus l , of the ballance is lessened : and by what proportion the mercury rises in the pipe , by that same , is the weight l augmented in the scale . we may subjoyn lastly , that the easiest way of explicating the phenomena of nature , is not always the best , and truest . for some may think , it were far easier to say , that the ballance supports the mercury ab , or de , and not any part of the water bc , or ef. but such a way would be false , and absurd , and contrary to all the former doctrine . experiment xii . figure . this schematism represents a water foot deep , whose first and visible surface is ihk . and lm is the ground of it . cd is a piece of brass inches high , and inches in diameter , suspended upon the imaginary surface of water anb , which is distant from the top ihk , foot . this brass cannot go farder down , when demitted from h ; because it 's keeped up , by the force and pressure of the surface of water anb , which i prove thus . the part b sustains de facto , a pillar of water kb pound weight : therefore the part n is able to sustain as much . i suppose here , the said piece of brass to weigh pound . the water kb is pound , because its a pillar foot high , and inches thick , for one cubical foot weighs pound trois . the connexion of the argument is evident , because it is as easie for a surface of water , to sustain a solid body , as to sustain a fluid body : therefore , if the part b , support the fluid pillar kb , the part n must be able to support likewise the solid pillar cd , which is of the same weight . if it be objected , that the part n , sustains besides the brass cd , a pillar of water ef foot high , and a half , which two will weigh pound . i answer , upon supposition , that neither water nor air succeeded , the space ef being void of both , the brass would be suspended with the force and power of the water n. and though this cannot be made practicable , yet the theory of it may conduce much for explicating the secrets and mysteries of the hydrostaticks . but why ought the brass to be suspended at foot from the top ? i answer , because the potentia of the surface anb , is equal to the pondus of the brass . to evidence this , consider that brass is a body naturally heavier then water , i shall suppose ten times , that 's to say , one inch of brass will counterpoise ten inches of water . if this inequality be , then must this pillar of brass go so much farder down , than the first surface ihk , as the one is heavier in specie , or naturally , than the other : therefore it must sink foot exactly ; seing a piece of brass inches high , requires inches of water , or foot to counterpoise it : for if one inch of brass require ten inches of water , then surely inches must require . yet it is no matter , what the thickness be , provided it be no higher than inches . to advance some farder , let us make a second supposition , namely , while the brass is thus suspended upon the surface anb , suppose the air to come down , and fill up the imaginary space ef , then must the brass be thrust down as far as the surface op , that 's foot below the surface and , and from the top . the reason of it is this , because the weight of the air superadded , is equivalent to the pressure of a pillar of mercury inches high , and inches thick : therefore the brass being burdened with this , it must go so farder down , till it meet with a surface , whose potentia is equal in weight , to the pondus of both , which is precisely foot from the top : for if one inch of mercury require of water , then inches must require inches , or foot . in a word , it must go as far down , as that surface , that sustains a pillar of water , that would counterpoise in a ballance , the brass cd , and a pillar of mercury inches high , and inches thick , both which weighs pound . from what is said , we see first , that of two heavy bodies differing in weight , the lighter may go further down than the heavier . this is clear , because a slender cylinder of gold , in form of an arrow , half an inch thick , and inches long , weighing pound ( 't is no matter , though the just weight of it be not determined ) will go down foot in water , before it meet with a surface , whose potentia is equal in weight to its own pondus ; for if gold be times heavier naturally than water , then the said cylinder must go down before it rest , inches , or foot . but a piece of gold inches long , and six inches thick , that perhaps will weigh pound , will sink no further than foot . and the reason is , because , if one inch of gold require of vvater to counterpoise it , then must only require , or foot . note , that both the bodies must go down perpendicularly , and not as it were horizontally , with their sides downmost : for if they go down after this manner , they cannot sink so far . the reason of this is also evident , because a heavy body goes so far down , and no further , till it hath thrust as much water out of its place , as will counterpoise it self in a ballance . that 's to say , if an heavy body weigh pound , it must go no further down , than after it hath thrust out pound of water . but so it is , that a piece of gold , in form of an arrow , going down side-wise , or with the two ends parallel to the horizon , will thrust as much water out of its place , as will be the weight of it self , before it can go down or inches from the top : because for every inch it goes down side-wise , it expells inches of water . in going down two inches , it expells . in going down three inches , it expells , and so forward , till it go down inches , where it expells inches : but inches amounts to foot . now , take a cylinder of water foot high , and just the thickness of the cylinder of gold , which i supposed to be of half an inch , and put them in a ballance , and you will find the one just the weight of the other . neither can the piece of gold go so far down as before , if it go down side-wise ; because for every six inches it is drowned , it expells a bulk of water inches long , and six inches thick ; therefore it must be suspended , before it go beyond inches , or seven foot and an half : now , if six inches give one foot , inches will give foot : but of water in hight , and six inches thick , is the just weight of it in a ballance , viz. pound . we see secondly , the broader and larger the surface of a fluid be , 't is the more able and strong to support an heavy burden : therefore the part of a surface of water six inches square every way , will carry a far greater weight , than a part four inches square . though a surface of water or foot deep , be not able to sustain a cylinder of gold. if it exceed or inches in hight , yet take a cylinder of gold , foot high , and reduce it , by making it thicker , to the hight of inches , a surface of water little more than foot deep will sustain it . or reduce a cylinder foot high , which requires a surface more than foot deep , to a cylinder six inches high , a surface little more than seven foot deep will support it . we see thirdly , the reason why bodies that are broad and large , move slowlier through air and vvater , than bodies that are more thin , and slender , though both be of the same weight in a ballance . for example , pound of lead , long and slender like an arrow , will go sooner to the ground of a deep vvater , than a piece of lead of the same weight , in form of a platter or bason . the reason is , because as the body is broader , so it takes a broader part of a surface , which broader part is stronger and abler , than a narrower part , and so makes the greater resistance . the same is the reason , why a bullet six inches in diameter , moves slowlier thorow the air , shot from a cannon , than a bullet one inch in diameter . for the same reason , ships of seven or eight hundred tun , move far slowlier thorow the air , and water , than vessels of less burden . item , large and big fowls , as eagles , move slowlier , than small birds , as swallows . yea , of fowls of the same quantity , one may move quicklier than another , as is evident in long-wing'd hawks , as falcons , that by the sharpness of their wings , move far more space in half an hour , than kites , or gose-hawks , whose wings are rounder . we see fourthly , that there 's no body how heavy soever , but it may be supported by the surface of a fluid , either in air or in vvater . i grant , the strongest surface of air , that can be had , is not able to support more weight , than a cylinder of gold inches high : yet though it were as large , and broad , as a mill-stone , if it do not exceed the said hight , the air is able to sustain it . for the same cause , if it were possible to free a mill-stone of the air , that rests upon it , the air below would lift it from the ground , and carry it up many fathoms , even till it came to a surface , equal in power to the weight of the stone . or , if a large mill-stone were demitted from the top of the atmosphere , towards the earth , it could hardly touch the ground , being detained by the way , by a surface counterpoising it . or if it did touch , through the swiftness of the motion , it would surely , as it were , rebound , and be carried up again . it is alwayes to be remembred , that in such trials , the air is supposed not to follow , or to be united , after the stone passeth thorow . now if the air be able to do this , far more the vvater , that 's a body a thousand times heavier . we see fifthly the reason , why heavy bodies move so easily thorow air , and water , namely because the parts that were divided , by the body that is moved , are presently reunited , and closed again , by which means it is driven forward , the pressure upon the back , being as much as the pressure before . if this were not , no body whatsoever would be able to move it self one foot forward . for example , if , when a man hath advanced one step forward , the air did not close again upon his back , the force of the air upon his belly and breast , would not only stop him , but violently thrust him backward . we see sixthly , the reason , why the same body descends with more difficulty thorow water , than air , because a surface of water is far stronger , than a surface of air. we see seventhly , that a heavy body is never suspended by a surface of water , or air , in going down , till once it hath displaced , as much water or air , as will counterpoise it self in a ballance . this is clear from the brass cd , that goes alwayes down , till it expell its own weight of water . for this cause , if a mill-stone were demitted , or sent down from the top of the air , and never rested , till it came within fathom of the earth , then so much air , as is expelled by the descent , is the just weight of the stone . we see eighthly , the heavier a body be naturally , than water , it goes the further down , and the lighter it is , it sinks the less . for if cd were of gold , it would go further down , than being of brass or iron : and if cd were a stone , that 's lighter in specie than brass , it would not go so far down . this lets us know the reason , why thicker , blacker , and heavier clouds comes nearer to the earth , than thinner , whiter , and lighter . vve see ninthly , that the pressure of the air is determinable , even in its heighest degree , and seemes to be the same in all places of the world ; but the pressure of the water is not so . the reason of the first part is , because the element of air seems to be of the same hight in all places , and therefore we may know its outmost pressure , which is just equivalent to the weight of or inches of gold , or mercury . but because the deepness of the sea is variable , therefore the pressure is variable likewise . yet if the exact deepness , of the deepest place were known , it were as easie to determine the greatest pressure of it , as to determine the greatest pressure of the air. we see tenthly , that a very small weight added or subtracted in height , will change and alter the counterpoise of a fluid . because if you lay but one ounce upon the top of the brass at f , it presently subsides accordingly : or take one ounce from it , and it rises . but though never so much weight be added to it , or subtracted from it in thickness , no alteration follows . therefore , though this piece of brass cd , that 's now but inches in thickness , were made , by which means the weight would be tripled and more , yet the same surface anb would sustain it : yet , add to it in altitude , but one inch , and presently it sinks down proportionably . this evidently discovers the reason , why it s as easie for the air , to support a cylinder of mercury inches thick , as to support a cylinder half an inch thick : and why it cannot support more in height than inches , and why it cannot support less . now the reason , why a thicker pillar , is as easily suspended , as a thinner , is this , because if a pillar of mercury be thicker , and consequently heavier , than i● takes a broader , and consequently a stronger surface of air to ●est upon : if it be but slender , and so but light , then it takes a lesser part of a surface to bear it up , and consequently a weake● ; by which means the pondus of the one , is alwayes proportionable to the potentia of the other . is it not as easie for a pillar of stone , foot in diameter , to support another six foot in diameter ; as it is for a pillar one foot in diameter , to support a pillar one foot in diameter ? but as a pillar one foot in diameter , cannot support a pillar foot in diameter , neither can a surface of air , one inch in diameter , support a pillar of mercury inches in diameter . but why should a larger part of a surface be stronger than a narrower part ? i answer , the one is stronger than the other , for that same reason , why a thicker cylinder is heavier than a thinner : for what i call strength in a surface , it s nothing else but weight , and what i call weight in a cylinder , it s nothing else but strength . the same thing hath two names , because the pillar of a fluid presseth down , and the surface supports : therefore , in the one it s called pondus , in the other potentia . as when two scales are in equilibrio , either this , or that may be called the pondus , or either this , or that , may be called the potentia . now i say , if a part of a surface four inches broad , have as much weight or force in it , as a pillar of mercury four inches thick ; then surely , a part of a surface eight inches broad , must have as much weight and force in it , as a pillar of mercury eight inches thick . but why ought a surface to succumb , when the pillar grows in hight , and not to fail when it grows only in breadth ? ans. vvhen it grows in breadth , the pondus never exceeds the potentia ; but when it becomes higher , then it becomes heavier . that 's to say , when a pillar grows broader , there 's not one part of the surface that sustains it , more burdened than another ; seing the part eight inches broad , is no more prest with a pillar eight inches thick ; than the part four inches broad , is prest with a pillar four inches thick : as eight ounce of lead in this scale , is no more counterpoised with eight ounce in the other scale , than four ounce in this scale , is counterpoised with four in the other . but when a cylinder grows in hight , the pondus exceeds the potentia ; one part of a surface being more burdened than another . we see eleventhly , that in a large surface of a fluid , wherein are many parts ; each part is able to sustain its own proper burden . so a part eight inches in diameter supports a pillar eight inches thick ; and a part four inches , supports a cylinder four inches thick ; but cannot support a pillar six inches thick . but this seems rather to slow from the disproportion of magnitudes , seing a circular plain inches in diameter , cannot receive a base of a pillar inches in diameter . but this is certain from the very nature of fluids , that in a deep vvater , wherein may be distinguished , or different surfaces , each one is able to support his own burden , and no more . experiment xiii . figure , , . for making this experiment , take two plain bodies of brass , or marble well polished . make them of any quantity ; but for this present use , let each of them be four inches broad square wise . upon the back part , let each one have an handle about six inches long , of the same metal , formed with the plain it self , in the founding ( if they be of brass ) as is represented in this schematism . when they are thus prepared , anoint their inner-sides with oyl or water , and having thrust the one face alongst upon the other , with all the strength you have , till all the four edges agree , two whereof are represented by ab , and cd , you will find them cleave so closs together , as if they were but one body . the effect is this , that ordinary strength will not pull them asunder ; and that under a surface of water , a stronger pull is required than in the air. that we may deduce some hydrostatical conclusions from this experiment , let us suppose these two plain bodies to be united in the middle of the vvater ikpq , that 's foot deep , and suspended by a beam or long tree tv existing in the air , near the top of the vvater , by a chord se passing between the middle of the beam , and the end of the handle at e. suppose next a great weight of lead r , pound , to be appended to the end of the handle at h , of the under plain body cdno . this done , i affirm , that the beam tv , neither sustains the under plain body cdnogh , nor the pound weight of lead r , that hangs down from the handle gh . if it be objected , that the beam supports the upper plain body ablmfe ; therefore it must bear the weight also of the under plain cdnogh , with the weight r ; seing they are both united together , and cleave so closs , as if they were but one body . i answer , it supports the one unquestionably , but not the other . to explicate this hydrostatical mystery , i must aver three things ; first , that the inferior plain is supported by the upward pressure of the lower vvater pqno . secondly , that the burden which the beam sustains , is not the weight of the under plain , but the weight of the foot of water iklm . thirdly , that this weight is exactly the weight of the inferior plain , and lead r. but is it not more easie to say , that the beam supports both the plains ? i answer , if i say so , i can neither affirm truth , nor speak consequentially , but may it not be said , that the inferior plain is supported both by the beam , and the lower water pqno ? i answer , this is impossible ; because one and the same weight , cannot be supported totally , by two distinct supporters . for making these assertions evident , i must suppose the superior water iklm to be foot deep , and to weigh , if it were put into a ballance , pound : and which is unquestionable , that the said water rests upon the back of the superior plain lm . i suppose secondly , that the lower water pqno weighs as much , and thrusts up the inferior plain with as great weight , as the superior plain is prest down with , by the superior water . this is evident from former experiments . and lastly , i suppose each plain to weigh two pound , and the weight of lead r . it is to be observed here , that no mistake may arise in the calculation afterwards , that though it be said , this foot of water weighs pound , yet in it self it weighs but : but considering the pressure of the air upon ik , which is as much , it may be truly said to weigh . these things being premitted , i say the weight that the beam tv sustains , is not the weight of the inferior plain , and the lead r , but pound of the superior vvater iklm , and consequently , that the inferior plain is supported by the lower vvater pqno . the reason is , because the lower vvater presseth up with the weight of pound . it is in it self pound : but being burdened with , it cannot thrust up with more weight than . now , it pressing up with , must ease the beam of , and counterpoise so much of the superior vvater , and consequently the beam must support only pound of it . but put the case ( you say ) the weight r , were pound , pound , or pound , would the beam be less or more burdened with the superior water ? i answer , if r be pound , then the beam supports only pound of the superior water ; for if the inferior be only burdened with , the weight of r , and with two the weight of the inferior plain , then must it press up with , and by this means , must ease the beam of so much , it sustaining pound only . according to this compting , when the lead r weighs pound , the beam supports only pound of the superior water . if it weigh pound , it sustains . and if the weight r were taken away , the beam supports no more of the superior vvater than two pound . to proceed a little further ; imagine the two plains to be drawn up foot nearer the first surface ik , namely as high as zw . this done , the union breaks up , and they presently fall asunder . the reason is , because the surface zw is not able to support pound , but only , which i prove thus . if foot sustain , then foot must sustain . i say , and not , because as was noted , the pressure of the air upon the surface ik , is equivalent to other foot : and therefore though the deepness of this vvater , between ik and lm be but foot really , yet it is foot virtually , and in effect . imagine secondly the surface ik to subside foot , namely to zw . in this case the union is broken also , and the lower plain falls from the upper . the reason of this , is the same with the former ; because by what proportion you diminish the hight of the superior vvater , by that same proportion you diminish the upward pressure of the lower vvater . therefore , if you subtract from the superior vvater foot , that weighs pound , you subtract likewise pound from the inferior vvater , and consequently , you make it press up only with , but is not able to counterpoise . let us suppose thirdly , the superior plain , and the superior water to be annihilated ; then i say , the pressure and force of the under water would thrust up the inferior plain and the weight r about eight foot higher then xy and there suspend them . the reason is , because the surface xy , being able to sustain , and being burdened only with , must have the weight of . now the upper plain being taken away , and the upper water also , and the empty space of both remaining , the said weight of pound , must carry the under plain as high as is said . let us suppose fourthly , the pressure of the element of air , that rests upon ik , to be taken away , then must the two plain bodies be disunited , the inferior falling from the superior . the reason is , because in this case , the superior water would have but the weight of pound , and consequently the inferior , would press up only with as much : but is not able to counterpoise . from what is said we see first , that in all fluids there is an upward pressure , as well as a downward ; and that the one is alwayes of equal force to the other : because the inferior plain is pressed up with as great force , as the superior plain is pressed down with . we see secondly , that in fluids , there is a pondus and a potentia . the potentia here is the inferior water , and the pondus is the superior . or , the pound of lead r , may be called the pondus , which counterpoiseth the potentia of the surface of vvater xy . we see thirdly , that though the pressure of a fluid , be not the same thing with the natural weight , yet it is equivalent to it : because the pound of lead r , is sustained by the pressure of the inferior vvater , which could not be , unless they were virtually the same . we see fourthly , that there may be as much pressure in one foot of water , as there is weight in , or in foot , or in fathom , for put the case , these two plain bodies were suspended , fathom below the surface of the sea , and within a foot or two of the ground , as much weight would be required to pull them asunder , as is the weight of a pillar of water fathom high , and inches thick every way , which will be more then pound weight , besides the weight of the air above , that will weigh pound . this could not be , unless there were as much pressure in the lowest foot of this water , that 's fathom deep , as there is weight in the whole pillar above . we see fifthly , the more the potentia of a surface is burdened , the more sensible is the pondus : because the heavier you make the lead r , that burdens the inferior water , the more weight of the superior water rests upon the beam. we see sixthly , the more unequally a body is pressed , the more the pressure is sensible . for understanding this , consider that the under-face of the superior plain , is more and less pressed , according to the more and less weight the lead r is of : for put the case , the inferior plain were taken away , the face of the superior plain , would be equally prest with the back of it . but when the inferior plain is united to it , the pressure of the water is kept off ; by which means the back is prest more than the face . now , as the inferior plain becomes heavier and heavier , by making the weight r more and more weighty , the less and less is the face of the superior plain prest up . hence it is , that as this inequality of pressure becomes greater and greater ; so the weight of the superior water , affects the beam more and more . or , if the superior plain were a sensible body , as animals are , it would find the back of it more and more burdened , according as the weight r , becomes heavier and heavier . we see seventhly , that water weighs in water : because all the weight the beam supports , is the burden of the superior vvater , and not the burden of the inferior plain , or of the weight r. it supports the weight also of the superior plain , but this is not considerable . this is only to be understood , when the pressure is unequal ; for if the upper plain were as much prest up , as it 's prest down , the weight of the superior vvater would not be found by the beam. we see eighthly , that the higher a surface be , it is the weaker ; and the lower it be , it is the stronger : because when the two plain bodies are pulled up , foot , they fall asunder . we see ninthly , the vanity of the common opinion , that maintains two plain bodies to cleave closs together for fear of vacuity ; and that neither humane nor angelick strength is able to break this union , without the rupture and fracture of them both . it may be enquired , upon supposition , that the inferior plain had four holes cut thorow the middle , square-wise , as abcd in the figure , what phenomena would follow ? before i answer , consider that this figure represents the inner face of the brass-plate cdno , of the figure , which as was supposed , is four inches from side to side , and consequently contains square inches . now , imagine the under plain cdno , while it is united to the uppermost , to have four square inches cutted out of it , as abcd. these things being rightly conceived , and understood , i say , when the said holes are cutted thorow the beam tv , that now sustains pound , shall by this means , only sustain pound . to make this evident , consider that the under plain ( as was said ) contains square inches . next , that the top of the inferior water upon which the plain rests , contains as many , and that every inch of the water weighs pound , seing the whole , as was supposed before , weighs pound . now , i say , the beam must support only pound of the water iklm ; because , these holes being made , the top of the inferior water comes through them , and presseth up the face of the superior plain with pound , and so easeth the beam of so much . i affirm next , that though the inferior water nopq be in it self pound , and consequently able to support the inferior plain , with the weight r , albeit they weighed so much , yet the said holes being cut out , it is not able to support more burden than . the reason is , because of parts that did actually bear up before , there are only now that sustains . and every one of these twelve , being but able to support pound , it necessarily follows , that the greatest weight they are able to sustain , is pound . i affirm thirdly , that if a fifth hole were cut through , the under plain would fall from the upper ; because in this case , the inferior water is not able to support pound as before , seing of parts , there are five wanting , and eleven remaining , cannot support more weight than pound . moe questions of this kind might be proposed ; as first , what would come to pass , if the the upper plain had as many holes cut through it , answering to the four of the nether ▪ secondly , what would folow , if the nether plain were intire , and four bored through the upper ? but i shall supersede , and leave these to be gathered by the judicious reader . from this experiment we see first , that the broader and larger a surface of a fluid be , it 's the more able to sustain a burden , and the narrower it be , 't is the less able . secondly , that each part of a surface , is able to sustain so much weight , and no more , and no less . before i put a close to this experiment , it will be needful to answer an objection , proposed by doctor more in his antidote against atheism , against the pressure of the air , which in effect militats , by parity of reason , against the pressure of the vvater likewise . he argues thus . if the air were indowed with so much pressure , as is commonly affirmed , then it ought to compress , squeez , or strain together , any soft body that it environs , as , v. g. butter . put the case then , there were a piece of butter , four inches broad every way , and one inch thick , containing square inches , upon every side ; as may be represented by the figure . in this case , there is a far greater pressure , upon the two faces , than upon the four edges ; and therefore , it ought to be comprest , and strained together , to the thinness of a sheet of paper . for answer , let us suppose the piece of butter , to be or foot below the surface of a water , where it ought to suffer far more pressure , than above in the air. next , that it lies horizontal , with one face upward , and the other downward . thirdly , that the upper face supports a pillar of water pound weight , and consequently , that the under face is prest up with as much . and lastly , that every edge is burdened with . it may be represented , with the help of the fancy , in the figure , where ab is a piece of butter four inches square , and one inch thick . only take notice , that nothing here is represented to the sight , save one of the four edges , namely ab ; the other three , and the two faces being left to the fancy : yet , the upper face may be represented by fhkm , and the under by nopq . these things being rightly understood , it is wondered , why the two great and heavy pillars of water , the one egilfhkm , that presseth downward , and the other nopqrstv , that presseth upward , do not strain together the sides of the butter ; seing the pressure of the water bc , and the pressure of the water da , are far inferior to them for strength , even by as much difference , as four exceeds one . though this objection seem somewhat , yet it is really nothing , which i make evident after this manner . first , i grant that the upper face fhkm is burdened , with pound , and the nether face nopq with as much . secondly , that the edge b , is only burdened , with pound , as is the edge a. the other two edges , sustains each one , as much . secondly , though this be , yet i affirm the two sides to be no more burdened , than the edges : that 's to say , the pressure upon the sides , is equal to the pressure upon the edges , which i prove thus . the pressure upon the part m , is equal to the pressure upon the part k , but the pressure upon the edge b , is equal to the pressure upon the part m : therefore the pressure upon b , is equal to the pressure upon k. the major proposition is evident , because the pillar of water lm , is of the same weight , with the pillar of water ik . the minor is also evident , because , the pillar bc , is of the same weight , with the pillar lm . now , if the pressure upon the edge b , be equal to the pressure upon m and k , it must be likewise equal to the pressure upon h and f. if this be , then the edge of the butter b , must be no more prest , than the side fhkm : therefore the water bc , can no more yeeld to the vvater efghiklm , and suffer the butter to be squeezed out at b , than the vvater lm , can yeeld to the vvater efghik , and suffer the butter to be squeezed out at m. if any man shall insist and say , that the upper face bears the weight of four pillars , which weighs pound ; but the edge b is only burdened with : therefore ought to yeeld to . i answer , according to the theorem , namely , that a thicker pillar of a fluid is not able to press , or move a slenderer , unless there be an unequal pressure , therefore the thick pillar , that presseth the face , cannot move the slender pillar , that presseth the edge : but there is here no unequal pressure , seing the water xyzv , is of the same hight with the four pillars that rests upon the face of the butter . i grant , if the said water were not so high , as the other is , by the one half ; then surely the butter would be squeezed out at b ; because the shorter a pillar be , the less pressure is in the surface under it ; therefore , there must be less pressure , according to that supposition in the water bc , then now is . or put the case , the pillar ik were shorter then gh , or lm , the same effect would follow , namely , a squeezing out of the butter from k. or , let us suppose the pillar ik , to be higher than gh or lm . in such a case , the weight of the said pillar would press through the butter . from what is said , we shall only inferr this conclusion , that equality of hight between pillars of a fluid makes equal pressure , and inequality of hight makes unequal pressure . therefore 't is no matter , whether they be gross or small , thick or slender , provided they be all of the same altitude . fig. pag. fig. pag. fig. pag. fig. pag. experiment xiv . figure . this schematism represents a vessel full of water foot deep . ef is a glass-pipe , open at both ends , about foot high , and one inch in diameter . abcd is a vessel of glass , or of any other metal , thorow whose orifice above , the said pipe comes down . bhi is a pipe going out from the said vessel , crooked with a right angle at h , that the orifice i may look upwards . that some hydrostatical conclusions may be inferred from this experiment , fill the lower vessel abcd with quick-silver almost ; then pour in as much water above it , as will fill the space abh , leaving from h to i full of air. next , thrust down the orifice of the pipe e , below the said water and mercury , till it rest upon the bottom cd . lastly , stop well with cement the passage of the lower vessel , through which the pipe came down , that neither air nor water may go out , or come in . these things being done , let down this engine to the bottom of the large vessel , which , as was noted , is full of vvater from mn to kl , foot , and you will find the mercury to rise in the pipe from ab to g , inches , and more . the reason is , because there is a pillar of vvater ki , that enters the orifice i , and presseth down the air , from i to p , inches , which before was . this air being so burdened ; instantly presseth forward the vvater hba : and this pressing the surface of the stagnant mercury ab , causes the liquor run up the pipe from ab to g , inches : the reason , why it riseth inches , is this : between the surface of the stagnant mercury ab , and the top of the water lok , are inches . now water being times naturally lighter then mercury , there must be inches of water , required for sustaining one inch of mercury , and consequently , for supporting . for a second trial , lift up the whole engine to the top of the water , and you will find the inches of mercury bg sink down , and become no higher within the pipe , than the surface of the stagnant mercury ab without . the reason is , because by coming up above the water , the pressure of the water ki , is taken away from the orifice i , by which means the comprest air hp , extending it self to i , liberats the water abh of the pressure it had , and this freeth the mercury of its pressure , and so the inches falls down . for a third trial , stop closely the orifice i , and let all down as before . in this case , you will find no ascent of mercury from b to g : because the water ki cannot have access to thrust down the air from i to p , as formerly . for a fourth , open the said orifice i , while the engine is below the water , and you will find the mercury rise from b to g : because the pillar of water ki , hath now access to press . for a fifth trial , stop the orifice i , and bring up all to the top , and you will find the six inches of mercury bg suspended , as if the engine were under the water . the reason is , because the stopping of the orifice , keeps the inclosed air ph , under the same degree of pressure it obtained from the water ki . for a sixth proof , open the same orifice i , while the engine is above the water , and you will find the six inches of mercury fall down , because the imprisoned air hp , obtains now its liberty ; and expanding it self from h to i , eases the water bh of the burden it was under . for a seventh , pour in inches of water at the orifice f , till it rest upon the top of the mercury at g , and you will find one inch fall down . pour in as much , and two inches falls down . in a word , pour in as much water , as will fill the pipe to o , and you will find the whole six inches fall down . the reason is , because the water ki , is not able to sustain , both the six inches of mercury and the water , that 's poured in ; any one of them being able and sufficient to counterpoise it , for an eighth trial , empty the pipe of the said water , and after the mercury is ascended from ab to g , as formerly , suck out the whole air between g and f , and you will find the mercury to rise from g to r inches . the reason of this is evident from the pillar of air sk , that rests upon the top of the pillar of water ki : for by sucking out the said air , you take away the pondus or weight , that counterpoised the weight of the pillar sk , therefore it finding its counterpoise removed , presently causeth the water ki , to enter farder within the crooked pipe , till it hath prest up the liquor to r. for a ninth trial , take the six inches of mercury bg , and put them into the scale of a ballance ; then take as much water , as will fill the tub between ab and o , and put it into the other scale , and you will find a most exact counterballance between them . the reason is , because if the water kh , or a pillar of that hight , be able to raise and counterpoise the mercury bg ; then must as much water , as fills the pipe betwen b and o , be the just weight of it . the reason of this consequence is , because these two waters are of the same weight : therefore , if the one be the just weight of it , the other must be so too . if it be said , that the water , that fills the pipe between b and o , is far thicker , then the water kh ; therefore they cannot be both of one weight . i answer , equality of altitude , in this ballance of nature , is equality of weight : therefore , seing the one water , is as high as the other , they must be both of one weight . if it be said , that a pillar of water between k and h , cannot counterpoise the six inches of mercury bg , both being put into a ballance : and the reason is , because the one is thicker than the other . i answer , this only proves that two pillars differing in weight in the libra or artificial ballance , may be of one weight in the natural ballance : because in the artificial ballance , bodies counterpoise one another , according to all their dimensions , but in the natural ballance , such as this engine is , fluids counterpoise one another , according to their altitude only . from the first trial , we conclude first , that water even in its own place gravitats and weighs , because this water by its pressure , de facto thrusts up inches of mercury . we see in the next place , that the pressure of a fluid , is as easily communicated horizontally , as perpendicularly ; because the pressure runs alongst from h to b. we see thirdly , that fluids , may have as much pressure begotten in them , even while they are environed about closely with solid bodies , whereby the superior pressure , immediatly and directly by perpendicular lines is keeped off , as if they were immediatly under the pressure : because the mercury abcd , is as much burdened with the pressure , that comes from h , as if the upper part of the vessel ab , were open to let in the superior pressure , by perpendicular lines . the air then under the roof of a house , is under as great a bensil and pressure , as the air without , that 's directly under the pressure of the atmosphere . vve see fourthly , that the pressure of a fluid , may be as easily communicated thorow the parts of heterogeneous fluids , as thorow the parts of homogeneous ; because the pressure of the vvater ki , is as easily communicated thorow the air ph , thorow the water hb , and thorow the stagnant mercury bd to the orifice e , as if nothing interveened but vvater . vve see fifthly , that mercury can suffer a pressure , as well as vvater or air ; because the six inches cannot rise from b to g , unless the stagnant mercury abcd were compressed , even in all the parts of it . from the second trial , we see , that there cannot be a pondus in a fluid , unless there be a potentia , to counterpoise it : for when you take away the water ri , by lifting up the engine to the top of the water , the mercury bg presently falls down . from the third trial , we conclude , that the pressure of a fluid , cannot be communicated thorow solid bodies : for when the engine is drowned below the water , with the orifice i , stopped , no ascent of mercury follows . we conclude from the fourth trial , that it is impossible for two fluids to counterpoise one another , unless they be in equilibrio ; because the water ki cannot sustain the mercury bg , unless it be of the same weight . from the fifth , we conclude , that a fluid may be keeped under the same degree of compression , after the superior weight that begat it , is taken away : for after the engine is brought above the water , with the orifice i stopped , the mercury bg is still suspended , even by vertue of the pressure , that 's in the stagnant mercury . this tells us , that a sphere of glass full of air , may retain its bensil , even though the whole element of air , that begat it , were destroyed . from the sixth we gather , that a fluid cannot abide under pressure , when the burden is taken away that begat it , or that keeped it under pressure : for by opening the orifice i , the air ph extends it self : and so are the vvater , and mercury within the vessel freed of their pressure likewise . we gather from the seventh trial , that in the ballance of nature , one scale cannot be more burdened then another ; or that two fluids cannot counterpoise one another , unless they be in equilibrio : for when you pour in inches of water , upon the top of the mercury at g , they thrust down one inch , that there may be a just equipondium , between them , and the opposite weight ki . we gather from the eighth trial , which was observed before ; first , that there cannot be a potentia in a fluid , unless there be a pondus to counterpoise it : for when you suck out the air go , which was the pondus , that counterpoised the air sk , this presently in stead of it , raiseth inches of mercury from g to r. we see secondly , that one pillar of air can counterpoise another , fluids of diverse kinds interveening : because the air sk , counterpoises the air within the pipe go , the vvater kp first interveening ; the air ph next interveening , and the stagnant , and suspended mercury interveening also . we see thirdly from this eighth trial , that the pressure of the atmosphere , may be communicated thorow diverse kinds of fluids , without the least diminution of its weight : because the weight of the pillar of air sk , is communicated , and sent down thorow the water ki , thorow the air ph , thorow the vvater hb , thorow the stagnant mercury bd , and up thorow the suspended mercury bg , till it suspend the inches between g and r , which is the just counterballance of it . we see moreover , that fluids counterpoise one another , according to altitude only , and not according to thickness and breadth ; by comparing the water ki , that 's but half an inch thick , to the mercury bg , that 's a whole inch thick . we see from the last trial , that when a fluid is necessitated , to counterpoise a fluid of another kind , in stead of a fluid of its own kind , it sustains no more of it , than what is the just weight of the fluid of its own kind , because the vvater ki , being under a necessity to counterpoise the mercury bg , in stead of so much vvater as would fill the tub , it sustains no more of it , than the just weight of so much vvater , as is said . we see secondly , that when two fluids of divers kinds , do counterpoise one another , that which is heaviest in speciè , hath alwayes the shortest cylinder . next , that the difference between their altitudes , is most exactly according to the difference between their natural weights , therefore bg is times lower than bo ; because mercury is times heavier than vvater . we see moreover , that though two cylinders of a fluid , can counterpoise one another in the natural ballance , such as this engine is , yet they will not do it in the artificial ballance : because though bg counterpoise ki in this ballance , yet in a pair of scales , the mercury will be as heavy again as the vvater . we see lastly , that notwithstanding of this , yet such a thing may be ; for if the orifice i , were made as wide as the orifice f , that the cylinder ki might be equal to the mercury bg in thickness , then surely the one would counterpoise the other in the libra or artificial ballance . experiment xv. figure . this schematism represents a water foot deep , as cdab , together with a crooked pipe of glass inh , the one half whereof is ip , inches high , and one inch wide , the other half is pnrh , of a far narrower diameter , with an orifice h. there is also an orifice at l , with a neck , about which is knit a small chord ml , for letting down this engine to the bottom of the vvater ab . for trials cause , fill the wide glass with mercury from p to k , and you will find it rise in the narrow pipe , as high as the orifice h. this being done , close hermetically , or with good cement the orifice l ; then by help of this chord , let all go down from the surface cd , till it be exactly foot from the top , and you will find the mercury thrust down in the narrow pipe , from h to r , inches and an half . let it down next , as much , and the mercury will be yet further thrust down , namely from r to n , the part hrn being full of water . for understanding the reason of this , consider that between n and e , are foot : for so high is the slender pillar of water , that comes from the top , and entring the orifice h , comes down thorow the pipe to n. consider next , that between the said pillar of water , and the mercury npk , there is a counterpoise : but this counterpoise cannot be , unless the pillar of water be foot high , seing between n and k are inches of mercury ; for each inch thereof requires of water . upon this account it is , that when the glass is foot drowned , inches and an half are thrust down from h to r. if it be objected , that the pressure and bensil of the inclosed air ik ; is equivalent to the weight of other inches ; and therefore the pillar of water ehrn , must be foot high , before a counterpoise can happen . i answer , 't is true that 's said , but you do not consider , that there is a pillar of air fe , resting upon the top of the pillar of water , that makes a compensation exactly . to speak then truely and really , the inches of mercury npk , have the weight of inches ; and the foot of water ehrn , have the weight of foot . for a third trial , let down the glass foot further , and you will find the water pierce up thorow the thick cylinder of mercury pk , and rest upon the top k. the only difficulty is to determine , how much will spring up before the motion of it cease ? 't is evident , that the water will ascend , because coming to the base of a thick and gross cylinder , that it cannot intirely lift , it must pierce thorow it , seing the force of such a pillar of water , is now much stronger , than the mercury : for in effect , the glass being drowned foot further , the pillar that comes down thorow the slender pipe , hath the just weight of inches of mercury : but cannot resist : therefore the water not being able to lift it , by reason of the disproportion that 's between the thickness of the one , and the slenderness of the other , it must pierce up thorow it . for clearing this difficulty , consider , that this glass cannot go down from one imaginary surface to another , v. g. from foot , where it was , till it come to , where it now stands , but there must be an alteration in the equipondium , seing by going down , the pillar of water ehrn grows h●gher , and consequently heavier ; and therefore , some vvater must pierce up thorow the mercury , for making a counterpoise ; for 't is impossible for two fluids to counterpoise one another , unless they be in equilibrio . consider secondly , that after the water is come to the top of the mercury at k , it will find difficulty to find a room for it self , seing the space between s and i is full of air. notwithstanding of this , it must ascend . i say then , after the glass is gone down from , to foot , there will be about four inches of vvater above k , which have reduced the inches of air ki , to ● , si . if it be asked , between what two things is the equipondium now ? i answer , the first was at r , between ehr , and rnpk . the second was at r , between nrhe , and npk . the third is now at s , between the inches of inclosed air is , as one antagonist , and the four inches of water sk , with the inches of mercury kp , and the water pnrhe , as the other . to make a fourth equipondium , sink the glass other six foot , till it be foot from the top cd , then must some more vvater spring up thorow the mercury ; this of necessity must be , seing the cylinder of vvater nrhe , is six foot higher , and so far heavier , than it was : if this be , then must the inches of air is , be reduced to less quantity ; seing 'tis impossible , for one fluid to become heavier , unless its opposite and antagonist become heavier too , for an equipondiums sake . note , that the air is , will not lose other four inches , with this six foot of vvater , as it did with the former . the reason is , because , if for every six foot the glass goeth down , the air were comprest four inches , it were easie at last to reduce it to nothing : for if six reduce it to four , and to eight , ought to reduce it to no inches , which is impossible . therefore i judge it must suffer compression , by a certain proportion , as we see upon a scale , the divisions of artificial or natural sines grow less and less , there being more space between and , than between and ; more between and , than between and , and so upward till you come to . therefore the second six foot , must reduce the inches , not to , but to circiter , and so forth . by the which means , though the glass should go down in infinitum , yet the air shall never be reduced to nothing , and there shall still some small quantity of vvater come up . or in such a case , the air may be so comprest , that it can be no more , all the disseminate vacuities being expelled . but suppose this to be at fathom , then at , where the pressure is stronger , there can be no equipondium , which is absurd , for where the pondus becomes stronger , the potentia ought to grow stronger likewise . i answer , the motion of condensation ceaseth indeed ; but there still remains a potentia , or rather in such a case , a perfect resistentia , whereby the air is able to resist the greatest weight imaginable , before it can be reduced to nothing , or suffer a penetration of parts , that 's to say , two parts to be in one space . from the explication of these phenomena we conclude first , that in water there is a considerable pressure , seing in letting down the glass foot , the mercury is prest down from h to r , and from r to n , in going down other foot . secondly , that inches of mercury are as heavy as foot of vvater : because the mercury kpn makes a just equipondium with the vvater ehrn . thirdly , that fluids not only of the same kind , but of different kinds , do counterpoise one another according to altitude , and not according to thickness ; because though the mercury kpn be far thicker , than the vvater eh , yet they counterballance one another , because a proportion is kept according to their altitudes . fourthly , that a fluid naturally lighter , may move a fluid naturally heavier , and thrust it out of its own place , because the water coming in at h , thrusts down the mercury to r , and from r to n , and so forth . fifthly , that of two fluids unequal in strength , debating together , the weaker of necessity must yeeld to the stronger , though the weaker be far heavier naturally than the stronger , as is evident in the mercury , that yeelds to the water . sixthly , that it is impossible for two fluids , so long as they are unequal in strength , to cease from motion , till they come to an equipondium ; because the water alwayes springs up thorow the mercury , till an equal ballance happen . seventhly , that one fluid of this kind , can counterpoise another fluid of the same kind , though there be divers fluids interveening : because the air fe , counterpoiseth the air ik , or is , notwithstanding of water and mercury interveening . eighthly , that there may be as much pressure in one inch of a fluid , as in a million ; because the inches of air is , have as much bensil in them , as is in the whole pillar of air ef , that goeth up from the top of the vvater , to the top of the atmosphere . ninthly , that when one fluid is under pressure , the next must be under the same degree of pressure , though they be not of the same kind , but of different sorts ; because the air is , the water sk , and mercury kp , are surely under the same degree of pressure ; otherwise the motion could not end . tenthly , that when two fluids of divers kinds do press one another , that which is naturally lighter , ascends alwayes to the higher place , and the heavier to the lowest : because the air is , is above the water sk , and the water sk is above the mercury . note , that this is not universal , but only happens when the lighter cylinder , is slenderer than the other , for if the mercury kp , were no thicker than the water pnrh , this would raise it intirely . eleventhly , that the compression of air to less space , is not according to arithmetical progression , , , , , , but according to some other proportion , which may be called uniform-difform . note here , that though this be true of the air , while it is comprest from a more quantity to a less , as here , or in a wind-gun ; yet it is not true of the pressure of the element of air , which is more and more from the top of the atmosphere to the earth , according to arithmetical progression , as in water . we see lastly , that the heaviest of fluids , such as mercury , press upward , as well as downward ; because the top of the mercury k , thrusts up the water ks , as well as it thrusts down the water pnrh . it may be enquired here , how far this glass would go down , before the inches of air ik were reduced to one inch ? i answer , its hard to determine ; but it seems it ought to go down more than fathom . in this case , there would be inches of water above k. let us suppose the orifice h to be stopped at that deepness , and the glass brought above the water ; then , when the said orifice is opened in the air , you will find the whole vvater pnrh thrust out : and not only this , but the whole mercury pk , spring out at the orifice h likewise , except a little that remains between n and h : the reason is , because the inches of air , being reduced to one , would be under a very great bensil ; therefore the weight being taken away that begat it , of its own accord , it would expand it self to its old dimensions ; which it could not do , unless both the inches of vvater , that 's supposed to be above k , and the mercury kp were thrust out of their places . experiment xvi . figure . this schematism represents a vessel full of vvater inches deep , namely from ln the first surface , to mr the bottom . from m to r in breadth are inches . there are here also two glass-pipes open at both ends ; the one , two inches wide , the other half an inch wide . both of them are inches long . xyo is a surface of stagnant mercury , among which the two ends of the pipes are drowned . ec is a pillar of mercury six inches in height , and so is gd , both of them raised to that altitude , by the pressure of the water upon the surface xyo . the pillar eca is supported by , and rests upon , the imaginary pillar ap. and so is the pillar gdb , supported by the pillar bq . there are three things that occurres here from this operation of nature to be enquired after . first , why ought the mercury to rise in the two tubs , after the vessel is filled with water ? secondly , why rather six inches , then seven or eight ? thirdly , what 's the reason , why it rises as high in the wide tub , as in the narrow ? i answer , the mercury rises from c to e , and from d to g , by the pressure of the water , that rests upon the surface xyo . before that the water is poured into the vessel , there is here a m●st equal and uniform pressure upon the surface xyo , both without and within the tub , namely from the air that rests upon it . but no sooner is the water poured in , but as soon the pressure becomes unequal ; the parts of the surface without the tub , being more burdened , then the parts c and d within . therefore , the part that 's less prest , must rise and climb up , till the pressure become equal : for it 's impossible that a fluid can cease from motion , so long as there is inequality of weight between the pondus and the potentia . if any doubt , let him pierce the side of the vessel , and when the whole water is run out , he will find ec and gd to have fallen down , which clearly proves the climbing up of the mercury , to depend upon the in-pouring of the water . for understanding the reason of the second , remember that mercury ( as we have often noted ) is counted times heavier then water ; therefore ec must be six inches , seing xyo is prest with the altitude of inches of water . it would be judged no marvel , to see the mercury rise from c to e , and from d to g , provided the face of the stagnant mercury were as high as zf . no more strange it is , to see the two mercuries rise , with the pressure of the water ; for in effect and really , the said water is the just weight of as much mercury as would fill between xo and zf . for understanding the third , remember ( as was noted before ) that fluid bodies counterpoise one another , only according to altitude : therefore 't is no matter , whether the tubs be wide or narrow . if it be enquired , how can one and the same water , counterpoise two fluids of different weights ? to say , that fluids counterpoise one another according to altitude , doth not clear the difficulty ; for it still remains to be asked , why they counterpoise one another after this manner ? therefore it seems , that if the water raise the mercury from c to e in the wide pipe , it must raise it in the narrow one from d to k. for answer , consider first , that as there are here two pillars of mercury ce , and dg within the two tubs , so there are here also two pillars of mercury ap and bq , under the two orifices , upon which the said two pillars stand , and rest . consider secondly , that the potentia or force of the pillar ap , is just equal to the pondus of the pillar eca : item , that the potentia of the pillar bq , is equal to the pondus gdb . thirdly , that the potentia of ap ▪ is most exactly equal to the potentia of bq ; and the reason is , because their tops a and b , are parts of the same horizontal surface . i say then , if ap be equal to eca , and bq equal to gdb , and ap , and bq , equal among themselves , then must eca be equal to gdb . the same water then , doth not counterpoise two bodies of different weight . i grant eca to be far heavier , than gdb , while they are weighed in a pair of scales , but the one is not heavier than the other , as they are weighed in this ballance of nature . from what is said , we see first , that in vvater there is a pressure , and a considerable weight . this is evident from the rising of the mercury . vve see secondly , that fluids counterpoise one another , only according to altitude . thirdly , that when a lighter fluid presseth up a heavier , there is no more prest up of it , than is the just weight of the pressing fluid , because the mercury ec , is just the weight of the vvater that presseth upon xyo . that 's to say , the part of the surface c , is no more prest with the mercury ec , than the part x , is prest with the vvater lzx . fourthly , if mercury were times heavier than vvater , only three inches would be prest up : if it were but seven times heavier , the altitude would be at s , inches above c. fifthly , it 's as easie for a large part of a surface , to sustain a large pillar , as 't is for a narrow part , to sustain a narrower pillar : because ap sustains eca , as easily , as bq sustains gdb . sixthly , that in fluids there is a pondus and a potentia : as is clear from the potentia of ap , that sustains the pondus of eca . the vvater likewise that sustains , hath a potentia , and the mercury ec is the pondus of it . seventhly , that there is alwayes equality of weight between the pondus and the potentia . so is the potentia of ap , equal to the pondus eca . eighthly , that the pondus begets the potentia . so the weight of the vvater , begets the potentia that's in ap. for make this vvater deeper , and you augment the potentia of ap. if you subtract from it , the potentia of ap grows less by proportion . or the weight of eca , may be said to beget the potentia of ap. to proceed a little further , let us suppose the air he to be removed . in this case , the mercury rises inches higher than e , or above c ; even as high as s. in the narrow tub it will climb up to k , if you take away the air ig . this comes to pass , by vertue of the pressure of the atmosphere , that rests upon ln . from this we gather ninthly , that there is a counterpoise between the air he , and the weight of the air that rests upon ln ; and that a slender pillar of air , is able to counterpoise a thicker : for he is far narrower than ln . tenthly , that the pressure of the air , can be communicated thorow divers kinds of fluids ; because the weight that rests upon ln , is sent down thorow the vvater lzx , and down thorow the stagnant mercury , and thrusts up the liquor from a to s , inches . eleventhly , that a lighter fluid may be made to press with greater burden , than a fluid naturally heavier ; because the weight of the air upon ln , raises inches of mercury , but the vvater raises only six . vve see twelfthly , that fluids have a sphere of activity , to which they are able to press up themselves , or fluids of different kinds : because fi●st , the stagnant mercury can raise it self no higher within the pipe , than it is without . next , the inches of water , can raise the mercury no higher than e. lastly , the weight of the atmosphere , can raise the mercury no higher than s , inches above e. for another trial , take out from among the water , the two pipes , and stopping closely the two under orifices , fill them with mercury to the brim . then thrust them down as before , and open the said two orifices , while they are below the surface xyo , and you will find the whole cylinder fall down from h to e , and there halt : and the whole cylinder in the narrow pipe falls down from i to g. or , if you please , before this be done , stop closely the orifice h , and the orifice i , and you will find the mercury go no further down than s , by opening the orifice a ; and no further down than k , by opening the orifice b. this leads us to a clear discovery of the reason , why the mercury subsides , and sinks down from the top of the tub in the baroscope , to the th inch , whatever the diameter of the pipe be . and this lets us see , that the mercurial cylinder is suspended by the air , after the same manner , that the mercury ec is suspended after : and that there is no more difficulty in the one , than in the other . experiment xvii . figure , . fig. pag. fig. pag. fig. pag. fig. pag. fig. pag. there are here several phenomena to be considered . first , that the water creeps in at the orifice g , and fills the under part of the glass from m to k. secondly , that not one particle of air comes out , all the time the vvater is in going in . thirdly , that this air is comprest from m to k , nine inches . lastly , that the ingress of the water , is according to unequal proportion : because while the glass passeth from a to b , more vvater creeps in at g , and fills the bottom , then in passing from b to c. and more in going down from b to g , than in going down from c to d , as is clear from the unequal divisions , , , , , , for understanding the reason of the first , remember that in this deep water , there is a pressure , and that this pressure grows , as the vvater grows in deepness . it is then by vertue of this , that the vvater creeps in , and fills the bottom of the vessel : for in effect , every part being under a burden , and being therefore desirous to liberat themselves from it , they take occasion to thrust in themselves , finding , as it were , more ease here , than without , the air within the glass , being under less pressure , than the vvater without . the second phenomenon is caused by the straitness and narrowness of the hole g : for this entry being no wider , than the thickness of a sack-needle , the air cannot go out , while the vvater is coming in ; that is , the passage is so strait , that the one cannot go by the other . this leads us to the reason of the third , for if not one particle of air go out , all the while the glass is in going down , then surely , the vvater filling between m and k , must compress the air , and reduce it from twelve inches to three . but the greater difficulty is , why the ingress of the vvater is according to unequal proportion . for understanding this , consider , that this inequality , is not caused by any unequal pressure that 's in the vvater ; for if this were true , then there ought to be less pressure in the surface f , than in the surface e , and less in e , than in d , which is false and absurd . this inequality then , must flow from the nature of the air it self , that naturally suffers compression after such a manner . 't is evident from the compression of air in wind-guns ; for less force is required to compress the fi●st span , than to compress the second : or contrariwise , more strength is required , to compress the third span , than the second ; more to compress the fourth , than the third , and so forth . 't is evident in all bodies endowed with bensil , as in the spring of a watch , that requires more strength to bend it . in the end , than in the beginning . for a second trial , pull up from the bottom of the water the glass lih , and when it comes above , you will find nothing in it . the reason is , because the vessel being open between t and s , the whole vvater ih , falls down by degrees ; but in effect , is really thrust out , by the strong bensil of the comprest air il , that now expands it self , when it finds the glass go up thorow the vvater , whose pressure is less , and less from the bottom to the top ▪ but the contrary effect follows , when the other glass is pulled up ; namely , the vvater remains within the glass , and the air above it , is thrust out by degrees , as the glass comes nearer to the top . for understanding the reason of this , consider first , that while the orifice g , is level with the lowest surface , where it now is ; that 's supposed to be fathom deep , there is a real counterpoise between the inclosed air gk , and the ambient vvater without : for with what force the one strives to be in , with the same force the other endeavours to be out ; and because they are in equal terms , therefore the one cannot yeeld to the other . if you please to give the victory to the vvater , then let the glass go further down ▪ but if you desire the air to overcome , then must the glass be pulled up . pull it then up from the place it is in , till it come to f , and you will find a considerable quantity of air come out at g , and after or minuts of time , emerge and come to the top a , in form of round bells , or bubbles . the deepness and groseness of the water thorow which the bubbles come , makes their motion so slow . the reason of this eruption , must be less pressure of water in the surface f , than in the lowest g , from whence the glass came . suppose then , the lowest to have six degrees of pressure , f to have five , e to have four , d three , c two , and b to have one : and supposing the inclosed air kg , to be equal in force to the pressure of the lowest fathom , it must then have six degrees of bensil in it . put the case then , that with six degrees of bensil , it come to the surface f , that hath but five , it must surely break forth , and overcome the force and power of that surface : for 't is impossible that two fluids can be unequal in force and power , but the strongest must overcome , and the weakest yeeld : therefore , when the orifice comes to f , the air being stronger than the water , breaks forth ; and as long doth this eruption continue , as inequality of power continues between the one and the other . in pulling up the glass from f to e , other five fathom , more air comes out . the reason is the same , namely less pressure in e than in f : therefore , when the inclosed air , that hath five degrees of bensil , comes to e , that hath but four , it must overcome , and so long must it be victorious , till by expanding it self , it be reduced to the bensil of four . in pulling up the glass from e to d , more air yet breaks out , because a surface of three degrees of pressure , is not able to resist four degrees of bensil . in passing from d to c , more air comes yet out for the same reason , till in going up to the top , where there is no pressure , no more air breaks out . 't is to be observed first , that the motion of the air up thorow the water is but slow , the medium being thick , and gross . secondly , that if the glass be pulled up quickly , from one surface to another , or contrariwise , let down quickly , it presently breaks in pieces . this comes to pass through the strong bensil of the inclosed air , that must have time to expand it self , otherwise it breaks out at the nearest : for it being of six degrees of bensil , and coming quickly to a surface of five , there happens an unequal pressure , the sides of the glass being thrust out , with greater force , than they are thrust in with . but if so be , the glass move slowly up , the inclosed air gets time to thrust it self out by degrees , so that whatever surface the glass comes to , there is little difference between the pressure of the water , and the bensil of the air. the reason why the glass breaks in pieces , while it goes quickly down , is likewayes unequal pressure upon the sides : for in passing quickly from a surface of five degrees , to a surface of six , the sides are prest in with greater force , than they are prest out with , and the reason is , because through the straitness of the hole g , the water cannot win in soon enough , to make as much pressure within , as there is without . 't is to be observed thirdly ; that if the orifice g be stopped , before that the glass be sent down , it will not go beyond three or four fathom , when it shall be broken in peices ; though the motion were never so slow : and this comes to pass , through the strong pressure of the water . fourthly , the stronger the glass be in the sides , it goes the further down without breaking : therefore a round glass bottle , will sink or fathom , before that it be broken with the pressure of the water . if a vessel of iron were sent down , it ought to go much further . an empty cask , or hogshead , will not sink beyond seven or eight fathom , without breaking , or busting ; yet a bladder full of wind , knit about the neck with a pack-threed , will go down fathom , yea without bursting . it may be here inquired , what sort of proportion is keeped by the unequal ingress of the water ? i answer , it may be known after this manner . let first down the glass one fathom , and having pulled it up again , measure the deepness of the water in the bottom , of it . next , having poured out that water , let it down two fathom , and pulling it up , measure the deepness , which you will find more , than afore . do after this manner , the third time , and the fourth time , till you come to the lowest fathom , and you will find the true proportion . from what is said we see first , that in water there is a pressure , because through the force and power of this water , the inches of air that filled the glass , are reduced to three . secondly , that this pressure growes , as the water growes in deepness : because there is more pressure in b , than in a , more in c , than in b ; and so downward . thirdly , that when air is comprest , by some extrinseck weight , the bensil is intended , and grows stronger by unequal proportion , as is clear from the unequal divisions , , , , , , . fourthly , two fluids cannot cease from motion , so long as the potentia of the one , is unequal to the pondus of the other : this is evident from the water 's creeping in at g , all the while the glass is in going down ; and from the air 's coming out , all the while the glass is in coming up . fifthly , that no sooner two fluids come to equality of weight , but as soon the motion ends : because , if the glass halt at d , e or f , in the going down , upon which follows a counterpoise , then doth the creeping in of the water cease . sixthly , there may be as much pressure in a small quantity of a fluid , as in the greatest : because there is as much bensil in the small portion of air , included between k and g , as there is of pressure , and weight , in this whole water , that 's fathom deep . seventhly , that the pressure of a fluid , is a thing really distinct , from the natural weight : this is evident from the pressure of the inclosed air gk , that 's more and less , as the pressure of the water km , is more and less , but the natural weight is still the same , seing the same quantity remains . eighthly , one part of a fluid , cannot be under pressure , but the next adjacent , must be under the same degree of pressure : this is also clear , because what ever degree of bensil the included air kg is under , the water km is under the same . therefore , when the one is under six , as in the lowest fathom , the other is under six likewise . and when the one is under five degrees of pressure , as in the surface f , the other is under as much . ninthly , bensil and pressure are equivalent to weight : because the water km , is as much burdened with the bensil of that small portion of air above it , as if it had a pillar of water fathom high upon it . tenthly , that the pressure of fluids , is most uniform and equal , and that two fluids of different kinds , may press as uniformly , as if they were but one : this is evident from the sides of the glass , that are not broken in pieces , by the strong bensil of the inclosed air , and heavy pressure of the inclosed water ; and this happens because the pressure without , is as strong as the pressure within . we see lastly , that water does not weigh in water , because when a man lets down this glass by the chord , to the lowest surface , he finds not the weight of the water km , that 's within the glass , but only the weight of the lead q. 't is certain , he finds not the weight of the water ih ; because it rests not upon the glass within , but is sustained by ' its own surface , the mouth of the glass being downward , and open . when i say water does not weigh in water ; the meaning is not , that water wants weight or pressure in it , but that this weight and pressure is not found , as the weight and pressure of other bodies are found , while they are weighed in water . for example , a piece of lead or gold , hung in the water by a string , the other end being fastened to a ballance in the air , gravitats , and weighs down the scale ; and the reason is , because lead and gold , are naturally and specifically heavier than vvater ; but a piece of metal of the same specifick weight with water , or vvater it self , cannot gravitat in vvater , or weigh down the scale of a ballance ; and the reason is , because the surface of water upon which they rest , bears them up with as great weight and force , as they press down with . if it be said , that the water km , rests upon the bottom of the glass within ; and therefore , if the man above , find the weight of the glass , he must find the weight of the water within it . i answer , the consequence is bad , because the weight of the water within , is sustained , and counterpoised by the weight of the water without , whereupon the bottom of the glass rests . that 's to say , as there is a pillar of water km within the glass , that presseth down the bottom , so there is a pillar of water without the glass , whereupon the bottom of the glass rests , and which bears up both . but the greater difficulty is this , the further down the glass goes , it grows the heavier , because of more and more water , that creeps in at g. now 't is certain , the weight q grows not heavier , therefore it must be the water within the glass , that makes the increase of the weight ; and therefore water must still weigh in vvater . if this argument had any strength in it , it would prove the weight of the vvater ih to gravitat and weigh likewise ; because the further down this glass goes , it grows the heavier , because of more , and more water , that creeps up from h to i. now 't is certain , the weight of lead b grows not heavier . behold , the difficulty is the same in both , and yet it were rashness to affirm the water ih to be found by a mans hand , when he pulls up the glass with a string , seing it is sustained by its own surface , and not by any part of the glass . though this might suffice for an answer , yet because the contrary is mantained by some , and that with a new experiment to prove it , i shall be at some more pains to vindicat the truth of what i have said . this new experiment to prove that water weighs in water , i found in a philosophical transaction , of august . anno . numb . , the invention whereof is attributed by the publisher , to that honorable and worthy person mr. boyl , whose conclusions and trials , i never much called in question , but finding this opposite , and contrary to what i have demonstrated , i shall crave liberty to say , amicus socrates , amicus plato , sed magis amica veritas ; and shall therefore examine it as briefly as may be . the words of the publisher are as follows . the author of this invention is the noble robert boyl ; who was pleased to comply with our desires , of communicating it in english to the curious in england , as by inserting the same in the latine translation of his hydrostatical paradoxes , he hath gratified the ingenious abroad . and it will doubtless be the more welcome , for as much as no body , we know of , hath so much as attempted to determine , how much water may weigh in water ; and possibly , if such a problem had been proposed , it would have been judged impracticable . the method or expedient , he made use of , to perform it , as near as he could , may easily be learned by the ensuing accompt of a trial or two , he made for that purpose , which among his notes he caused to be registred in the following words . a glass-bubble of about the bigness of a pullets egg , was purposely blown at the flame of a lamp , with a somewhat long stem turned up at the end , that it might the more conveniently be broken off . this bubble being well heated to rarify the air , and thereby drive out a good part of it , was nimbly sealed at the end , and by the help of the figure of the stem , was by a convenient weight of lead depressed under water , the lead and glass being tyed by a string to a scale of a good ballance , in whose other there was put so much weight , as sufficed to counterpoise the bubble , as it hung freely in the midst of the water . then with a long iron forceps , i carefully broke off the seal'd end of the bubble under water , so as no bubble of air appear'd to emerge or escape through the water , but the liquor by the weight of the atmosphere , sprung into the un-replenish'd part of the glass-bubble , and fill'd the whole cavity about half full ; and presently , as i foretold , the bubble subsided , and made the scale 't was fastned to , preponderate so much , that there needed drachms , and grains to reduce the ballance to an equilibrium . then taking out the bubble with the water in it , we did , by the help of a flame of a candle , warily applyed , drive out the water ( which otherwise is not easily excluded at a very narrow stem ) into a glass counterpoised before ; and we found it , as we expected , to weigh about four drachms and grains , besides some little that remained in the egg , and some small matter that might have been rarified into vapors , which added to the piece of glass that was broken off under water and lost there , might very well amount to or grains . by which it appears not only , that water hath some weight in water , but that it weighs very near , or altogether as much in water , as the self same portion of liquor would weigh in the air. the same day we repeated the experiment with another sealed bubble , larger then the former ( being as big as a great hens-egg ) and having broken this under water , it grew heavier by . drachms and grains ; and having taken out the bubble , and driven out the water into a counterpois'd glass , we found the transvasated liquor to amount to the same weight , abating or grains , which it might well have lost upon such accompts , as have been newly mentioned . thus he . figure . the design then of this experiment is to prove that water weighs in water ; but , it seems , there is here a very great mistake , which i shall make out after this manner . for which cause , let this schematism represent the experiment already described . the glass-bubble then is epfr . the stem is hc : the weight that sinks the glass is b. the surface of water under which it is drowned , is ad. the ballance to which the glass is knit by a string is no . and lastly efr is the water that came in , and filled the half of the bubble . now i say , it is not the weight of the water efr , that turnes the scales above , and makes an alteration in the ballance , but ' its only the weight of the lead b , that does it . for evincing this , consider that all heavy bodies , are either lighter in specie than water ; as cork , or of the same specifick weight with it , as some wood is , or last●y heavier in specie than water , as lead or gold. now 't is certain , that bodies of the first sort cannot weigh in water , and the reason is , because they being naturally lighter , their whole weight is supported by the water , and therefore not one part of them , can be born up by a ballance above . a piece of cork that weighs ounces in the air , weighs nothing in water , because as soon as it toucheth the surface , the whole weight of it is supported , and therefore cannot affect the ballance above . but bodies of the third sort , as is clear from experience and reason , does really weigh in water : and the reason is , because they being naturally heavier than water , their whole weight cannot be supported by it , and therefore some part of them must burden the ballance , to which the body is knit . a piece of lead , that weighs ounces in the air , will not lose above ounces , when ' its weighed in water ; or may be less . but here there is no difficulty . the question then is , in order to bodies of the same specifick weight with water , as some wood is , or as water is . i say of such also , that they cannot weigh in water ; and the reason is , because they being ●ust of the same weight , must have their whole weight supported by it ; even as one foot of water , supports the whole weight of the foot above it . it may be evidenced after this manner . take a piece of wood , that 's lighter in specie than water , and add weight to it by degrees , till it become of the same weight with water . knit it with a string to a ballance , ond weigh it in water , and you will find the whole weight supported by the water . and the reason is , because , being left to it self , it can go no further down , than till the upper part of it , be level with the surface of the water . now , the whole weight being thus supported , not one ounce of it can burden the ballance . in a word , the ballance can never be burdened , unless the body that 's knit to it , have an inclination to go to the ground , when left to it self , which a body of the same weight with water can never have . i conclude then , if a body of the same weight with water , cannot weigh in water , neither can water weigh in water , seing water is of the same weight with water . and therefore the water efr , that 's now within the bubble , cannot in anywise burden the ballance above ; but must be supported wholly by the water ikgh , upon which the bottom of the glass rests . if it be said , that the glass it self is supported by the ballance , because ' it s heavier in specie than water ; therefore the vvater within that rests upon the sides of it , must be supported likewise by it . i answer , the whole weight of the glass is not supported , by the ballance , but only a part ; the vvater ikgh supporting the other part . and this part is just as much as is the weight of vvater , that 's expelled by the glass . now , if the said vvater support so much of the glass , because it is the just weight of so much vvater , why should it not also , support the vvater within the glass ? seing the vvater within the glass , is just the weight of as much vvater , as will fill the space efr . i come in the next place to shew , that it is the weight of the lead b that turns the scales , when the vvater comes in at c , and fills the half of the sphere . for understanding this , let us suppose first , the weight that 's in the scale o to weigh six ounces . secondly , that the glass takes ounces to sink it compleatly under the surface ad. thirdly , the weight b to be ounces ; namely for this cause , first , that of it may sink the glass ; next , that the other six may counterpoise the six in the scale o. lastly , that the vvater within the glass weighs six ounces . i abstract from the weight of the glass it self , which is not considerable , seing the most part of it , is suppo●ted by the vvater , and not by the ballance . now , i say , 't is six ounces of the weight b that makes this alteration , and turnes the scales . for if ounces sink the glass below the vvater , when ' its full of air , and no water in it , then surely six are sufficient to sink it , when it is half full . and the reason is , because there is a less potentia or force in six inches of air , by the one half , to counterpoise a weight of ounces , than in inches of air. therefore this air , being reduced from inches to six , it must take only six ounces to sink it . if this be , then the other six ounces that now wants a party to counterpoise them , must burden the ballance , and be supported by the scale : and therefore , to make a new equipondium again , you must make the weight o ounces , by adding six to it , that it may counterpoise of b , the other six being counterpoised by the air epf . let us suppose next , this glass to be compleatly full of vvater , and the whole air expelled . in this case the scale o , must have ounces in it , for making a new equipondium . the reason is , because there being no air in the glass to counterpoise any part of b , the whole weight of it must be sustained by the ballance , and therefore in the scale o , there must be . now , i enquire , whether these ounces , are the equipondium of the vvater within the glass , or of the weight of lead b ? 't is impossible it can counterpoise them both , seing the vvater is now , and b . it must then either be the counterballance of the water , or the counterballance of the lead . it cannot be the first , because cannot be in equipondio with , it must then be the second . or if these ounces in the scale o , be the counterpoise of the water within the glass , i enquire what sustains the weight of the lead b ? the weight of it , cannot be sustained by the water , because 't is a body naturally heavier than water , it must therefore be sustained by the ballance , i conclude then , that water cannot weigh in water . if it be objected , that this conclusion seems to contradict , and oppose the pressure of the water , that 's been hitherto confirmed with so many experiments . i answer , the pressure of the water is one thing , and water to weigh in water is another . the first is , when one pillar of water counterpoises another , or when a pillar of water counterpoises a pillar of mercury , or is counterpoised by a pillar of air , all which is in order to the natural ballance , wherein bodies weigh only according to altitude . the second is , when vvater is not counterpoised by vvater , or by mercury , or by air , or by any other fluid ; but when ' its weighed by a piece of lead or stone in an artificial ballance , for knowing how many ounces or pounds it is of , as if a man should endeavour to weigh the water efr by help of the ballance above , which in effect is impossible . experiment xviii . figure . make a wooden ark after this following manner . the planks must be of oak , an inch thick . the height inches . the breadth . closs on all sides , and above , and open below . and because the form is four-square , there must be four standarts of timber , in each corner one , to which the planks must be nailed . four likewise upon the top , crossing the other four at right angles , to which the cover must be joyned . the sides must be plained , and the edges both plained and gripped in all the parts , that the joynings m●y be closs . upon the top fasten a strong iron ring , as at n , through which must be fastned a rope , of so many foot or fathom . and because the use of this engine is for diving under the water , it must therefore be all covered over with pitch within and without , especially in the couplings . and because this instrument cannot sink of its own accord , it must have a great weight of lead appended to it , for that cause , whereupon the divers feet must stand , while he is in going down . the precise quantity and weight of it cannot be determined ; because it depends upon the quantity of the ark , which if large , requires a great weight : if of a lesser size , requires a lesser weight . but whatever the dimensions of the ark may be , the weight of the leaden-foot-stool can easily be found out by trial . this invention then , is for diving , a most excellent art , for lifting up of guns , ships , or any other things , that are drowned below the water . and it is in imitation of the diving bell , already found out , and made use of with success . it is called a bell , because of the form , that represents a church-bell indeed , being round , wide below , and narrower in the top : only , the matter is of lead . it seems , it is of this mettal , first , because lead is weighty , and will therefore easily sink : secondly , because it 's easily founded , and will by this means , being of one piece , be free of rifts , and leaks : thirdly , it being of lead , will be of a considerable strength for resisting the force of the vvater , that ordinarily breaks in pieces vessels that are weak . i cannot well d●vine and guess the reason , why first it is round , and next narrower above , than below , unless , because its more easily founded after this way , than after another . this device here described is named a diving ark ; first , because it is of timber , and next , because it saves a man from being overwhelmed with the waters . i prescribe it of wood , because of less trouble , and expence in making of it . 't is four square , because it contains under this figure , far more air , than if it were round ; even as much more , as a square vessel inches wide , contains more than a round vessel inches wide . now , the more air , that 's in the vessel , the easier is the respiration , and the longer time is the man able to abide under the vvater , which two things are of great advantage to this art. for if by a guess we reckon , how much more air is in the one , than in the other , we will find in the ark , as before it is described , square foot of air , but in the bell , though it be inches wide , as well above , as below , yet little more than will be found , which is a considerable difference . but far less must be in it , seing it's narrower above , than below . besides this advantage , there are others very useful : for being of wood , it 's more tractable . next , several knags of iron may be fastened conveniently to the sides within , to which a man fastning his hands , may keep his body fixed and sure in going down , and coming up . moreover , if a man were in hazard to be confounded with fear , or lose the right exercise of his senses , and so be in danger of falling out of the ark ; or if his feet should slide off the foot-stool , and his hands fail him too , a chord knit to one of those , and fastened about his wast or middle , might bring him up , though he were dead . then , it s far easier to cut out a window or two in the sides of it , not very large , but little , as k and i , whereby , they being covered with glass , a man may see at a distance , what 's upon the right hand , and what 's upon the left , and what is before . this device is of excellent use , for through the want of it , the diver sees no more , but what is just below him , which sometimes , when he is near the ground , will not exceed the compass of a large miln-wheel . but if so be , three holes be cut thorow , one on every hand , and one before , he may see as much bounds , and all things in it , as if he were not inclosed , and invironed with a cover . a little schelf likewise may be fixed upon the one side or the other , for holding a compass with a magnetical needle , for knowing how such and such a thing lies in the ground of the sea. in one of the corners may hing a little bottle with some excellent spirits , for refreshing the stomach , under vvater . many moe advantages i might name , this engine being of timber , but shall forbear ; leaving the collection of them to the ingenious reader , and proceeds to answer some objections , that may be made against it . first , if this engine be made of wood , it will not sink so easily , as being made of lead . i answer , this difficulty is soon overcome , namely by making the foot-stool the heavier : therefore how light soever it be , a weight may be found to counterpoise it in the vvater , if it be judged too light in timber , it may be lined with lead , especially without . secondly , if it be of vvood , there must be couplings and joynings in it , and so rifts and leaks in it , through which the vvater may come . i answer , there is less difficulty here , than in the former ; because the joynts may be made so closs in all the parts , and may be so covered over with pitch , or with some such like matter , that it may defie either water to come in , or air to go out . thirdly , if it be made of vvood , it will be in hazard of breaking by the force of the vvater : for oft times its found , that the strongest hogshead will burst asunder by the pressure of it , if they go but down or fathom . i answer , this objection flows from the ignorance of the nature of fluid bodies . if so be then , that a man knew , that the pressure of vvater is uniform , most equal , and presseth upon all the parts of a body within it alike , no such scruple would occurre . i say then , the ark , though no thicker in the sides , than a thin sawen dale , will go down , in spight of all the pressure that 's in the vvater , not only , but , or fathom , without all hazard . and the reason is , because what pressure soever is without , to press in the sides , the same degree of pressure is within to press them out . by this means , there is not one part of the vvater , how deep soever , to which the ark may come down , but there will be found as much force in the air within , as will counterballance the whole weight without , as will be infallibly demonstrated afterwards . this answers a fourth objection , namely if holes be cut out in the sides of the ark , in stead of windows , the force of the vvater will break the glasses in pieces , that covers them . there is here no hazard , though the said windows were inches in diameter : but it s not needful they be so large . it 's sufficient , if they be inches wide : for a mans eye near to a hole , inches wide , will see a great way about him . there 's a necessity the glasses be joyned in with cement , that water may not have access to come in , or air to go out . in such a case ther 's no hazard , that the pressure of the vvater , will break through the windows , or break the glasses ; because the pressure of the air within , being of the same force with the strength of the vvater without , the glasses are keeped intire . it may be enquired , what hazard would follow , upon supposition a small hole were pierced in the head of the ark above , when it is going down ? i answer , ther 's not so much hazard , as a man would think ; provided the hole be not wide , but narrow . if it be wide , not only the vvater comes in , but the air goes out , the one thrusting it self by the other . if the hole be no wider , than the point of a bodkin is in thickness ; ther 's no danger at all : for by reason of the strait passage ; the one cannot thrust it self by the other , and therefore neither the vvater can come in , nor the air go out . and this comes to pass , by reason , that the air within , is as strong as the water is without . now , if they be both of the same strength and force , why ought the air rather to go out , then the water to come in ; or the water rather to come in , then the air to go out ? i am confident , though the hole were as wide , as a man might thrust in his little finger , yet no irruption of water , or eruption of air would follow . this demonstrats clearly , that though a small rift , or leak should happen in the ark , yet no hazard or danger would follow thereupon . if it be inquired , whither the greatest hazard is from the ingress of the water , or from the egress of the air ? i answer , ther 's no danger from the coming in of the water from above ; because as it comes in , it falls down , and so mingles with the rest below . but if the air should go out , the ark fills presently full of water , and drowns the man that is in it . the next thing considerable in this diving instrument , is the foot-stool of lead cd , that 's not only useful for a man to set his feet upon , when he dives ; but especially for sinking of the ark. for this being made of timber ; and full of air , cannot of ' its own accord go down , unless it be pulled , and forced by some weight . it may either be broad and round , or square : if square , a large foot over from side to side , or inches will determine the breadth . by this means , it will happen to be pretty thick , seing a great quantity of lead is required . in each corner , there must be a hole , for four chords , by which it is appended to the mouth of the ark. between it , and the roof within , must be the height of a man and more . the weight of it , cannot be well determined without trial ; seing it depends upon the dimensions of the ark. first then try , how much weight , will bring the top efgh level with the surface of the water . when this is found , add a little more weight till it begin to sink , and this will surely take it to the ground , though it were fathom . 't is to be observed , that when the top ef is level with the surface , there is here a just counterpoise , namely between the lead foot-stool on the one part , as a pondus , and the ark on the other part , as a potentia ; for with what force the ark endeavours to pull up the lead ; with the same force strives the lead to pull down the ark. hence it is , that as a small weight will turn a pair of scales , when they are in equilibrio ; so a small weight added to the foot-stool will sink the ark. though it may seem difficult to determine the just weight of the foot-stool , without trial as i said , yet i purpose to essay it . for this cause consider that there is no vessel of vvood almost , if it be once full of water , but the orifice of it will ly level with the surface of the vvater , wherein it sweems . this proposition is so evident from experience , that it needs no confirmation . from this i gather , that as much weight of lead or stone will bring the top of the ark efgh , level with the surface of the vvater , as is the weight of the water , that fills it . if you suppose then the ark to be inches broad , and inches high , it must contain cubique foot of water . now , supposing each square foot of this water to weigh pound , foot must weigh pound . this is gathered from trial and experience , for after exact search , i found a cubique foot of water , in bulk about pints of our measure , to weigh pound . take then a piece of lead of that weight , and you will find it make a just counterpoise with the ark. if any be desirous to know the quantity of it . i answer , if lead be times naturally heavier then water , you will find that a piece of lead about inches every way will do it . if it be objected , that when a mans body is within the ark , the weight of the foot-stool must be less , even as much less , as is the weight of the man , whom i suppose to weigh pound , or stone . i answer , the whole weight of the man is not to be deduced from the foot-stool , but the one half only , and the reason is , because a mans body being of the same specifick and natural weight with water , it cannot preponderat or weigh in vvater , because magnitudes only naturally heavier then vvater weigh in vvater , as lead , or stone ; therefore seing the one half of the man is within the ark , and the other without among the water , that part only must weigh , that 's invironed with air. this may seem a plausible answer , and might do much to satisfy these , that are not very inquisitive , yet , being examined , it will be found unsufficient . therefore , i say , there 's not one part of the mans body , that weighs within the ark , or makes it heavier . yet , i affirm , that when the mans body is within the ark , a less weight will sink it , then when his body is out of it , even as much less than before , as is the just weight of the one half of the man. for example , if pound be the just counterpoise of it without the man , then after the man is in it , it will take only pound to counterballance it , supposing the one half of the man to weigh pound , or seven stone : yet it is not the weight of the man that makes this difference . for understanding what 's the cause of this alteration , consider , that when a mans body is within the ark , there is less air in it , then while his body is out of it , even as much less in quantity , as the bulk of the parts are , that are within . if this be , then must the ark become heavier , not because the mans body makes it heavier , but because there is less air , in the ark , then before , and therefore , there arises an inequality between the weight of the foot-stool and the weight , or rather lightness of the ark. for if pound of lead , was the just counterballance of it , when it had cubique foot of air within it , it must exceed , when there is less air in it . but there occures , here two difficulties , the first is , what 's the reason , why as much weight must be deduced from the foot-stool , as is the the precise weight of the one half of the man ? secondly , how shall we come to the true knowledge of that weight ; that is , to know distinctly how many pounds or ounces it is of ? for answer , let us suppose , that the one half of the man , is just as heavy , as so much water equal in bulk to his own half . this may be granted without scruple , seing a mans body is judged to be of the same specifick , and natural weight with water : and though there should be some small difference , yet it will not make , or produce any insufficiency in the argument , for these demonstrations , are not mathematical but physical . therefore , as much water in bulk , as is equal to that part of the man , that is within the ark , must be as heavy , as the half of the man. now supposing the half of the man , to weigh pound , and consequently that water , to weigh as much , i affirm the said water to contain cubique inches : but cubique inches , makes exactly two cubique feet , which i gather thus . seven pound of water requires cubique inches , because a cube of six inches , weighs exactly seven pound , therefore according to the rule of proportion , pound will require inches , which amounts to two cubique foot . the ark then by receiving the one half of the mans body , loseth two cubique foot of air , therefore if foot of air , require pound weight of lead to counterpoise it , foot of air , must require only pound : therefore to make a new counterballance , you must deduce pound from the foot-stool . this answers both the difficulties . if it be said , that the foot-stool weighs less in vvater than in air , therefore it must be heavier , then pound . i answer , 't is needful to abstract from that difference , till the just calculation be once made , and that being now done , i say , that a cube of lead inches weighing pound , ( if lead be times heavier than vvater , ) will lose about pound . the reason is evident , because a heavy body weighs as much less in vvater than in air , as is the weight of the water it expells . but so it is , that a cube of lead of inches expells a cube of vvater inches : but a cube of vvater inches weighs pound , which i gather thus . inches , or a cube of six inches , weighs seven pound , therefore inches , must weigh pound . for if give , must give . but to return . though there be small difficulty to let it down and to sink it or fathom , yet there is no small difficulty to pull it up again . and the reason is this , because the further down it goes , the air within , is the more contracted , and thrust up , by the pressure of the water , towards the roof . by this means , though near the top of the water , there was little difference between the weight of the lead and the ark ; yet or fathom down , the difference is great , the weight of the one , far exceeding the weight of the other , and therefore there must be greater difficulty to pull it up from fathom , than from : and yet more difficulty from than from . however , yet 't is observable that , as the ark in going down , becomes heavier and heavier , so in coming up , it growes lighter and lighter : therefore less strength is required , in pulling it up from the tenth to the fifth fathom , than from the fifteenth , to the tenth : the reason is , because in coming up , the air within expands it self , and fills more space in the ark , which in effect makes it lighter , and more able to overcome the weight of the lead . to make these things more evident , let us suppose , that when the ark is down or fathom , the air to be contracted by the force of the water , from lm to pq inches . next , that the weight of the foot-stool is pound . now , if this weight was the just counterpoise of the ark , at the top of the water , then surely it must far exceed it now , when it 's fathom down , because the air that was foot , is now reduced to . count then , and you will find , that if require , will only require : therefore the weight of the lead , will exceed the weight of the ark , at fathom deep , by pound . this will be yet more evident , if we consider , that while the top of the ark efgh , is level with the surface above , the vvater thrust out of ' its own place by this bulk , is just the weight of both lead and ark. but when ' its down fathom , and the air reduced from lm to pq , there cannot be so much vvater expelled now as before , seing the space lmpq is full of vvater . now , i say , the lead at fathom , must be exactly so much heavier than the ark , as is the weight of the said vvater lmpq , which in effect will be . pound : for ' its a square body , inches in thickness and in deepness . the weight of the rope is likewise to be considered , that lets down the ark : for the longer it be , and more of it goes out , it 's the heavier , and more troublesome to pull up . there is no way to cure this difficulty , but by finding out a way , how to keep a just counterpoise between the lead and the ark , all the time it is in going down . if the air within did not contract it self , no difference would happen : but this is impossible , so long as the water is under a pressure . the expedient then must be found out another way , namely by kniting a small rope to the iron ring n , in length with the other , to which at certain distances , relating to the fathoms the ark goes down , must be fastned empty little vessels of wood , or bladders , which by their lightness , may compense the decrement and decreasing of the air. first then , let down the ark three fathom , and see how much it is heavier than before : and as you find the difference , so fasten to r one bladder , or two , till the ark be brought near to a counterpoise . secondly , let it go down other three fathom , and observe that difference also , and accordingly fasten to t as many , as will reduce the two to a counterpoise again . do after this manner , till it sink or fathom . 't is to be observed , that the further down the ark goes , the difference is the less : therefore less addition will serve : and the reason is , because there is less air contracted , in passing between the fifth and the tenth fathom ; than in passing from the first to the fifth . the proportion of contraction is represented by the unequal divisions within the mouth of the ark , as . . . . in a word , by what proportion the decrement of the air is , by that same proportion must the addition be , upon the rope sn . suppose then , the air to be diminished four inches , in going down four fathom , which will be square inches , or three square foot , then surely as much air must be added to the rope sn , by bladders . in going down as far , let us suppose three inches to be contracted ; then less will suffice . though it cannot be determined without trial , how much air is contracted in three fathom , and how much in six , and how much in nine ; yet this is sure , that the decreasing is according to unequal divisions , that 's to say , less in six than in four , less in , than in six , and less in , than in , and so downward : and that this is the rule , namely according to what quantity , the air within the ark is contracted , according to that same measure , must the addition of air be to the rope . if it be said , that bladders full of wind , cannot go down thorow the vvater without bursting . i answer , 't is a mistake , because their sides being pliable , and not stiff like the sides of a timber vessel , they yeeld , and therfore cannot burst . it 's observable that when a bladder goes far down , the sides becomes flaccid and slagging . in this case , the air , that before , had the forme of the bladder , and was somewhat ovall , must now become perfectly globular , and round : for 't is sure , that the dimensions of it are altered by the pressure of the vvater , namely from more quantity to less : if this be , then the form must be round , seing the pressure of the water is most uniform ; even as drops of vvater , or rain from a house side are round upon this account . this second way , may be thought upon also . make the leaden foot-stool that sinks the ark , not of one piece , but of many , that so , when the air within it , begins to be contracted by degrees , in going down , a proportionable weight may be subtracted , for keeping a just counterpoise , all the while of the descent . or because the greatest trouble is in bringing of it up , let the diver , when once he is at the bottom , subtract so much weight from the foot-stool , as he thinks will go near to make a counterpoise , at that deepness . for example , if the weight of the foot-stool be pound heavier than the ark , then let him subtract or , which may ly , and rest upon the ground , till it be drawen up , at a convenient time , by a chord . by his means it will be easie to move the ark , from one place to another . next , there shall be little or no difficulty to pull it up . nay , upon supposition , the rope were broken , by which it was let down , yet if the diver please , he may come up without any mans help . and this is most easily done , namely by subtracting as much weight , as will make the ark the stronger party . 't is to be observed , that when you are at the bottom , and if you make the lead but one pound lighter than the ark , it will surely come up , and cannot stop by the way . the reason is , because a very small weight will turn the scales , between two bodies , thus weighing in vvater . next , the further the ark comes up , it becomes the lighter , because the air within it , expands it self the more . but leaving this , let us come to explicat the reason , why the contraction of the air is not uniform , but rather difform . for if in going down three fathom , three inches be contracted , there will not be other three contracted in going down the second three , but less : and yet less in going down the third three . two things then are to be explicated here . first , why there is a contraction . next , why it is after such a manner . as for the first ; the contraction is caused by the pressure of the water , which gradually increaseth from the top to the bottom ; as is clear from the last experiment : therefore , there being a greater pressure in a surface six fathom deep , than in a surface three fathom deep , the air within the ark , must be more contracted in passing between the third and sixth , than in passing between the first and third . when i say more contracted , the meaning is , that more quantity is contracted to less , whereby the bensil of it is more intended ; or that the air is more bended . as for the second , we must remember from the last experiment , that the cause of this , is not from the vvater , as if forsooth the pressure of it , were according to unequal proportion , but from the air it self , whose kind and nature it is , to suffer compression after such a way . 't is evident in wind-guns , whose second span of air is comprest with greater difficulty , than the first : and the third with greater difficulty , than the second . 't is so with all bodies endowed with bensil : for ay the longer you bend , you find the greater difficulty . as there is a great disadvantage to the man that dives , from the contraction of the air , so there is a great advantage to him , from this manner and way of contraction ; for if it were uniform , according to the pressure of the water , then if three fathom comprest three inches , six fathom ought to compresse six inches , nine fathom nine inches , and so forward , till by going down , either the whole air , should be comprest to no inches , or else very little should remain for respiration . the next thing to be taken notice of , is that all the while , during the down going of the ark , there is still equality of weight , between the pondus of the water , and the potentia of the air , for with what degree of weight , the water presseth up the air , with the same degree of force and power , doeth the air press down the water . if this were not , it would be impossible for a man to go down ; because of pain . for when one part of a mans body , is less prest than another , there ariseth a considerable pain , which sometimes is intolerable , as is evident from the application of ventoso-glasses . this equality of weight , is the true reason , why respiration is so easie . yet 't is to be observed , that a man cannot breath so easily in the ark , under the water , as above in the air ; not because there is any inequality , between the weight of the vvater , and the force of the air ; but only because the quantity of it is little . for when a man sucks in as much air , as fills his lungs , the quantity must be diminished : if this be , the water must ascend by proportion , though insensibly . when a man thrusts out the same air again , the quantity is increased ; if this be , then the water must subside a little ; both which cannot be , without difficulty , seing there is a sort of ebbing and flowing both of the air and of the water , in every respiration . but it rather seems ( you say ) that this difficulty flowes from the strong , extraordinary bensil , that the air is under . i answer , as long as the pressure of a fluid is uniform , though in a high degree , yet there can be no trouble in respiration ; because with what force soever , it is driven in upon the lungs , with the same force it is driven out again : therefore , though the air we live in , were as much again bended as it is , yet ( as is probable ) we would find no more difficulty in breathing than now . there is one thing makes breathing easie under the water , in the ark , namely this ; when a man sucks in the air to his lungs , his breast and belly goes out , and so fills the space deserted by the air , that goes in . this makes the ebbing and flowing far less . from this equality of weight between the pressure of the vvater , and the pressure of the air , we see good ground to say , that though the ark , were no thicker in the sides , than a thin sawed dale , yet there would be no hazard of breaking . i am confident , though it were no stronger in the sides , than a wine-glass , that 's soon broken ; yet it might go down fathom without hazard , or danger of bursting . this affords good ground likewise to make windows in the ark covered with glass : for if the pressure be uniform , and equal , its impossible they can be broken . the vvater cannot thrust them inward , because the pressure of the air , is as able to thrust them outward . it 's certain , the more air be in the ark , the more easie is respiration : therefore it s more easie to breath , when the ark is but down fathom , than when it is down or . it 's probable a man might live within the ark , it being inches deep , and inches wide , at the deepness of ten fathom , near two houres ; whereas if it were round , and narrow above in form of a bell , he could not continue an hour . it were very easie to try how long other creatures might live in it , for example dogs , and such like , or fowls , as hens , pheasants or doves . they might easily be inclosed from coming out ; for though the whole mouth of the ark were shut up , except as much passage , as would receive a mans fist , yet it will operate , as well that way , as the other . and there , a little door might be made to open , and shut at pleasure . 't is observed , that by long tarrying under the water in the bell , the air becomes gross and misty , which hinders a man from seing about him . the cause of this , are vapors that come from the stomach , lungs and other parts of the body , especially from the stomach , when the ventricle is full of meat . it 's not fit then , that a man about to dive , should eat too much , or drink too much , especially such liquors as sack or brandy , that beget many fumes and vapors . if a man were necessitated to tarry a pretty while below , fresh air might be sent down from above , in bottles or bladders , even as much as might fill up the place deserted by the contracted air. 't is observed by some , that have been under the vvater , that their eares have been so troubled , that for a long time , they have found difficulty to hear distinctly . the reason of this must be from the great pressure , the tympanum hath suffered from the imprisoned air of the bell. the organ of hearing is soon troubled , especially when a man is near to a great gun , when it 's fired . and surely , when a man is but foot down , the air within the ark , will be of double bensil : put the case the man go down foot , or or fathom , the bensil is tripled : that 's to say , if the air above have five degrees of pressure in it , the air of the bell , at foot deep , will have degrees of pressure ; therefore the tympanum of the ear that 's but a small and thin membran , must be sore distressed ; that is overbended , and prest inward ; even as , while a man sets upon a drum head a great weight , v. g. a bullet of lead or iron , of or pound , the skin by this , suffers an extraordinary pressure , whereby it is in hazard to be rent . 't is probable , if a man should go very far down , the tympanum might be in hazard of breaking , or being rent in two pieces , there being a greater pressure upon the one side from the air without , than upon the other side , from the internal air within , which is thought to be within the tympanum . there remains another phenomenon to be explicated , and it 's this : the further up the ark comes from the ground of the water , towards the top , the water within it , subsides and settles down more and more , towards the mouth . the reason of it is , because the further up , the pressure of the water is the less ; and therefore the contracted air gets liberty to expand , and dilate it self , and so thrusts down the water from pq to lm . in a word , by what proportion the air is contracted in going down , by that same proportion it dilates , and opens it self in coming up . this lets us see , as there is disadvantage in going down , from the contraction of the air , so there is advantage in coming up , from the dilatation of it . some think , that the coldness of the water is the cause , why the air is contracted in the ark , such are those , who deny the pressure of it . but this fancy is easily refuted ; because in asserting this , they must maintain , the further down , the cold is the greater . if this be , then far more air must be contracted , in going down from to fathom , than in passing from to ; seing as they say , the further down , the cold is the greater ; and therefore the contraction of the air must be the greater ; that 's to say , there must be more quantity of air contracted in the one space , than in the other . but so it is , that the further down , the contraction is the less . they judge likewise the coldness of the water to be the cause , why the sides of empty vessels are broken in going down . but if this be , then a strong vessel should go no further down than a weak vessel ; seing cold can pierce thorow the sides of the one , as well as thorow the sides of the other . and why is it , that a bladder full of wind will go down or fathom without bursting , yea , and yet a stone-bottle or glass-bottle , cannot go beyond or ? if cold have in it , that power to break the sides of a strong bottle , it must be far more able to burst the sides of a thin bladder . this difference is clearly explicated from the pressure of the water ; but i defy any man to shew the difference from the coldness of it . 't is to be observed , that in all such experiments of sinking of vessels , as hogs-heads , barrels , and bottles , they must be closs on all sides . therefore , if a man desire to know , how far down a glass-bottle is able to go without bursting , he must stop the mouth of it exactly , with a piece of wood , and cement . in setting down the dimensions of the ark , i have restricted them to inches high , and inches wide . but if any man be desirous to enlarge them , or make them less , he may do it . only 't is to be observed , that the larger the ark be , the foot-stool that sinks it , must be the heavier . yet it hath this advantage , that it contains much air , which is the great perfection of it . one of a lesser size hath this advantage , that it 's more tractable , and easier to let down , and to be pull'd up . but these things are best known from experience , or if a man please , he may calculate . as the ark is a most useful device for profit , so 't is excellent for pleasure , and recreation , if a man were disposed to see the ground and channels of deep vvaters , or were inclined to find out hydrostatical conclusions , a knowledge very profitable , and which few have attained to . though it seem somewhat difficult to enter the ark , and go down below the water , yet a little use will expell all fear . then , a man may go down with less hazard , and fear in the ark , then in the bell , because he may conveniently fasten his hands , to each side of the ark , if need were . he may conveniently sit , as in a chair , all the time of down going , and up-coming , by fixing a little seat in it : he may have windows to look out at : his body may be so fixed , that there needs be no fear of falling out . if a man were desirous to make hydrostatical conclusions , by diving under the vvater , the dimensions of the ark might be enlarged , so that it might conveniently cover a mans whole body , by which means , having much air in it , a diver might continue under water half a day , if need were . let us suppose then , the hight of it to be foot , and the breadth foot , or more . in such a case , a man might continue under the vvater many hours ; and yet not one part of his body wet : for if the ark be foot high , and the man foot in stature , at the deepness of fathom , the water can scarce rise foot in it . but why may not a man come up every half hour , when he finds difficulty to tarry down in a little ark ? i answer , he may ; but it 's trouble and pains to pull him up , and let him down so frequently . and it may so happen , that through want of air in a small ark , he be necessitated to come up before he end his work . and leaving the work imperfect , he may find difficulty in the second down going , to find sometimes the place where he was , or the thing he was about to lift , v. g. a chest of gold. if it be said , that a great weight of stone or lead is required to sink an ark foot high , which will amount to pound weight . i answer , 't is so indeed : but here is the advantage ; when it is once below the surface , there 's little more trouble , then with an ark of lesser dimensions ; because of the equipondium that's between it , and the weight , that sinks it . in such a vessel many trials might be made . as first , that of the torricellian-experiment , which is nothing else , but a glass-tub so many inches long , with a mercurial cylinder in it of inches high , that 's supposed to be kept up at that hight by the pressure of the air. if this were taken down about foot , 't is very probable the mercury would rise other inches . the reason is , because the air within the ark , that presseth upon the surface of the stagnant mercury , must be under as much pressure again , as the air above ; but the air above , is able to support ; therefore this air must sustain . the reason why the bensil is exactly doubled is this , foot of water hath exactly as much pressure in it , as the whole element of air ; therefore , the air within the ark , being foot down , must not only have in it the pressure of the air above , but the pressure of the water likewise : this necessarily follows , because when two fluids touch , or are contiguous to other , the one cannot be under five degrees of pressure , unless the other be under as many . according to this reasoning , if the ark go down foot , the mercury will rise from to . if to , it rises . this reckoning is founded upon this , namely that water is times lighter than mercury ; and therefore one inch of mercury requires of water to support it in a tub , and therefore , before water is able to raise inches of it , the pipe must be foot deep . for a second trial , blow a bladder as full of wind as it can hold , and having knit the neck about with a pack-threed , place it in the ark , and you will find the sides , that hath been stifly bended become flaccid and feeble , as if the one half of the wind had gone out , and this will come to pass , before the ark can go down eight or nine fathom . the strong bensil of the air within the ark is the cause of this : for as the ark goes down , the air grows stronger , and so at length becomes of that power and force , that it easily overcomes the force and bensil of the air of the bladder , and reducing it to less room , causes the sides become flagging . in this case , the said air , that was oval , and had the form of the bladder , must become round in form of a globe , because of the uniform pressure , that it suffers from the air of the ark. when once the ark is down or fathom , take the same bladder , and blow it stiff with wind , and knit the neck as afore . and you will find that in the up-coming , the sides of it will burst asunder with a noise . when the bladder is thus full of wind , 't is supposed , that there is a sort of counterpoise between it , and the air of the ark. but as the ark ascends , the air of it , becomes weaker and weaker , while in the mean time , the air of the bladder suffers no relaxation ; therefore , when the ark comes near the surface , there arises a great disproportion between the one air and the other , as to strength , and therefore the air of the bladder being the strongest , rents the sides in pieces , and comes out with a noise . or , blow it but half full of wind , and you will find before , the ark come near to the top , the said bladder to be bended to the full . for a third trial , take a glass , such as they use in caves , for preserving of brandy , and stopping the mouth closely , take it down with you in the ark ; and you will see , the sides of it break in pieces , before you go down four or five fathom . the strong bensil of the ambient air , is the cause of this . if you take it down with the orifice open , no hurt shall befal it . or if you stop the orifice in the up-coming , you will find the same hurt come to it . but here is the difference , in the first bursting , the sides are prest inward , by the ambient air ; in the second , the sides are prest outward , by the air within the glass . for a fourth trial , take a round glass-bottle , pretty strong in the sides , and when it is down with you in the ark or fathom , stop the mouth of it exactly , and when it comes above , you will find a considerable quantity of wind come out of it , when the orifice is opened . this evidently demonstrats , that the air within the ark , , , or fathom down , is under a far stronger bensil then the air above . for a fifth trial , let a man apply to his skin a cold cupping-glass , when he enters the ark ; and he will find such a swelling arise within it , as when it is applied hot by a chyrurgion . this tumor begins to rise , assoon as the ark begins to go down . the reason is evident from unequal pressure , the parts within the glass being less prest , than the parts without . for a sixth trial , take a common weather-glass , and place it in the ark , and in the going down , you will see the liquor cre●p up in it , by degrees , as the ark goes down , as if some extraordinary cold , were the cause of it . and as the ark comes up by degrees , the said liquor creeps down by degrees . the cause of this phenomenon is not cold , as some might judge , but the strong bensil of the air within the ark , that so presseth upon the surface of the stagnant water , that it drives it up . if you take with you , a weather-glass , hermetically sealled , no such thing will follow ; because the outward pressure is keeped off . 't is not then cold , that 's the cause , but weight . by the way take notice , that all common weather-glases are fallacious and deceitful ; because the motion of the water in them , is not only caused by heat , but by the weight of the air , which sometimes is more , and sometimes less , as frequently i have observed , and as hath been observed by others . this difference is found , by the alteration of the altitude of the mercurial cylinder , in the baroscope , which is more and less , as the pressure of the air changeth . in fair weather , and before it comes , the mercury creeps up . in foul and rainy weather , and a pretty while , before it fall out , it creeps down . because in fair weather , the weight of the air is more , than in rainy and dirty weather . december , . . i found the altitude inches , and nine ten parts of an inch : at this time the heavens were covered with dry and thick clouds , and no rain followed . march . . i found the altitude no more , than inches , and nine ten parts , at which time , there was a strong wind with rain . between these two termes of altitude , i have found the mercury move near a twelve moneth . 't is a most sure prognosticator , for if after rain , you find the mercury creep up in the morning , you may be sure , all the day following will be fair , notwithstanding that the heavens threateneth otherwayes . if after fair weather , the mercury subside , and fall down a little , you may be sure of rain within a short time , though no appearance be , in the present . it falls down likewise , when winds do blow . what the true cause is , why there is such an alteration in the pressure of the air , before foul weather , and fair , and in the time of it , it is not easie to determine . but we proceed . trial likewise might be made , by firing a great piece of ordnance above , whether the report would be heard below the water or not ? this would determine the question , whether water be a fit medium for conveying sound as air is . item , whether or not , the sea water be fresher at the bottom , than near the top , which is affirmed by some . item , whether sounds be as distinct in such a small portion of air , as they are above . this might be tried with a bell of a watch. if need were , a little chamber bell might be hung within the ark , and a small chord might pass up from it , through the cover , whereby the persons above , might by so many tingles , speak such and such words to the diver . i have demonstrated before , that though there were a little narrow hole made in the cover above , yet neither air would go out , nor water come in . if a man were curious , he might have a window not only in the sides , but in the roof above , covered with a piece of pure thin glass , thorow which he might look up , after he is down two or three fathom , and see whether there appeared any alteration in the dimensions of the body of sun or not , or seemed nearer . we now come to infer some hydrostatical conclusions , as from former experiments . we see then first , that in water there is a pressure ; namely from the strong bensil of the air within the ark , that groweth stronger , and stronger , as the water groweth deeper , and deeper . we see next , that the pressure of the vvater hath an increment : because the further down the ark goeth , the air is the more bended . thirdly , two fluids cannot be contiguous one to another , unless both of them be under the same degree of pressure : because the air of the ark , and the water that creepeth up within the mouth of it , are perpetually under the same degree of power , and force , whatever the deepness be . fourthly , that in fluids the pressure is uniform ; because the air of the ark , and the water without , press most equally , one against the other . fifthly , the more that the air is bended , it is the more difficult to bend it ; and consequently , that the diminution of the quantity , is according to unequal proportion . sixthly , that when the ark is down foot , the bensil of the air is doubled : and tripled , when it s down foot : because the pressure of foot of vvater , is as much as the whole pressure , that 's from the atmosphere . if it be enquired , how much weight rests upon the palm of a mans hand , when the ark is down about foot ? i answer , the pressure of the water upon a mans hand , at that deepness with the pressure of the air above , will be equivalent to the weight of a pillar of mercury inches high , and three inches thick , which will exceed in real weight pound . if so much rest upon the palm , how much must rest upon the rest of the parts of the body ? let us suppose then , the quantity of the palm , to be found in a mans skin , times , then must he suffer as much pressure , and actually support as much burden , as will amount to pound weight . seventhly , our bodies may be under a huge pressure , and yet that burden not perceptible ; as is evident from the diver , who findeth little or no weight , while he is under the water . or if there be any pressure found , it 's not comparable to that , which really is . eighthly , when a man is or fathom down , at every inspiration and expiration , his breast and belly must lift up the weight of pound : because , if the whole burden be , the weight that rests upon the breast , and belly , will be about . ninthly , that between every inspiration , and expiration , there happens a perfect counterpoise , namely by the air , that goeth into the lungs , and the outward air of the ark : for if the pressure of the one , were more , than the pressure of the other , there could be no motion of the lungs . tenthly , when a man draweth his breath , the air cometh not in by suction , but by pulsion . for this cause , though the vvind-pipe were stopped , yet a man might live by having a hole in his side , going into the lungs . lastly , that there is no such thing as suction properly ; and therefore the motion of all fluid bodies , is caused by pressure and weight . the motion of the blood then thorow the heart , is driven , and not sucted . infants properly do not suck , but have the milk squeezed into their mouth . 't is evident from the sucking-glass that some women use for milking their own breasts : for by help of this , the air that guardeth the head of the pap is removed , and so the air , that presseth the parts about , and without , squeezes out the milk . fig. pag. experiment xix . figure . this figure represents a deep water , whose first and visible surface , is fg. the imaginary surface , is elc , foot below it . adb is a siphon , working below this vvater with mercury . ael is a vessel with stagnant mercury , among which the orifice a is drowned , the other orifice b existing among the water ▪ dm is the hight of the siphon above the line of level , which i suppose is inches . for making it work , stop the two orifices closely , and pour in as much mercury at a hole made at d , as will fill both the legs . then stopping the said hole , open the two orifices a and b , and you will find the liquor run as long out at b , as there is any almost in the vessel ael . for evincing this , which is the only difficulty , consider , that if this siphon , were filled with water , and made to work only with air , ( as is clear from daily experience ) the liquor would run out constantly at b. because there is here an unequal pressure ; the surface of air nb , being more burdened , than the surface elc , but where unequal pressure is in fluids ( according to the th theorem ) motion must follow , i prove the surface nb to be more burdened , than the surface elc , because the water bd , is heavier than the water ld , as is evident to the eye . the air b therefore , sustaining far more weight , than the air el , must cede and yeeld . next , there is here a pondus and a potentia , the pondus is the vvater ld ; the potentia by which it is counterpoised , is the water bd ; but these are unequal , bd being heavier , than ld ; therefore according to the theorem , these two fluids cannot cease from motion . if it be said , that the surface nb is stronger , than the surface elc , seing it is lower . i answer , the difference is so unsensible , that they may be judged but one . now , i say , if this siphon work in air , with water , it must likewise , work in water with mercury . therefore , this siphon being foot below the first sur●ace fg , the liquor must run out constantly at b. because , there is here , an unequal pressure , the surface of vvater nb , be●ng more burdened , than the surface elc. though there be more weight in nb , than in elc , because it is lower , yet because the difference is not so much , as is between the weight of bd , and the weight of ld , it proves nothing . note here , that so long as d , is within inches of el c , this siphon will work . the reason is , because the pressure of foot of vvater , with the pressure of the air , upon fg , are able to raise mercury exactly inches . but if d exceed that hight , no art will make the liquor run out at b. note secondly , that this siphon will operate with air and vvater , though the top d were foot above m ; and the reason is , because the pressure of the air , is able to raise a pillar of water to that hight . note thirdly , that if there were an orifice opened at c , upon the level line elc , the two waters would become of the same weight , the one not being able to move the other . if you bore a hole at r , the liquor ascends from r to d , and goeth down from d to a , and so the motion ends . but , if the leg ad were six times wider , than bd , the liquor would not run out at b. i shall answer this in the close . from this experiment we see first , that the motion of fluid bodies up thorow pumps , and siphons is not for shuning vacuity , but because they are prest up violently . we see next , that when the pressure is uniform , there is no motion in fluids ; but assoon , as one part is more prest , than another , motion begins : because , this siphon will not operate , if the orifice be made in c ; but if so be , it be in d , then the motion begins ; because there is here an unequal pressure , which was not in the other . we see thirdly , that fluids have a determinate sphere of activity , to which they are able to press , and no further : because this water , is not able to press mercury higher than inches . so the air cannot raise water higher than foot . if this water were foot deep , the sphere of it's activity would be inches . we see fourthly , that in fluids there is a pondus and a potentia ; and that the inequality of weight between the two , is the only cause of motion . we see fifthly , that as long as this inequality of weight continues , as long continues the motion , because , as long as bd , is heavier than ld , the motion perseveres . we see sixthly , the possibility of a perpetual motion in fluids ; because the liquor runs perpetually out at b. if it be said , the motion ends , when the stagnant mercury ael faileth . i answer , this stop is only accidental , and not essentially from the nature of fluids . if it be enquired , whether or not , would the mercury run out at b , upon supposition , the shank ld were twice as wide , as the shank bd ? i answer it would . if it be said that the one is far heavier than the other , namely ld than db. i answer , weight in fluids is not counted according to thickness , but according to altitude . experiment xx. figure . this last is for demonstrating the precise and just weight of any pillar of air , water , mercury , or of any other fluid body , if some of their dimensions , be but once knowen . ab then is a square pipe foot high , and six inches in wideness , full of water , resting upon the surface of air ac . and eg is a square pipe foot high , and inches wide , full of vvater , resting upon the surface of air ef. none needs to doubt , but the two waters , will be suspended after this manner , even though the orifices a and e were downward , especially if they be guarded with water , but the demonstrations , will be the more evident , that wee suppose the two pillars of water to be suspended as they are . from this experiment i say first , that the pillar of air cd is pound weight , at least ; which i prove thus . the vvater ab is pound : therefore the air cd , must be as much . i prove the antecedent , because it 's a pillar of vvater foot high , and six inches thick : but every half cubical foot of vvater , that containes inches , weighs seven pound : therefore seing the pillar is foot , it must contain half feet ; but times is . the only difficulty is to prove the connexion , which i do thus , from the seventh theor. all the parts of a fluid in the same horizontal line , are equally prest , but so it is , that the part a , and the part c , are in the same horizontal surface ; therefore the part a , and the part c , are equally prest . but if the part a , and the part c , be equally prest , the pillar of air cd , must be as heavy , as the pillar of vvater ab . i say secondly , that the pillar of air fh , weighs pound , i prove it thus . the water eg weighs pound ; therefore the air fh , weighs as much . the antecedent is clear , because eg , is a square pillar of vvater foot high , and inches thick ; but every cubical foot of vvater weighs pound : but times , is . i prove the connexion , as before . all the parts of an horizontal surface , are equally prest ; therefore the part f , must sustain as much burden , as the part e. to proceed a little further , let us suppose the pipe ab to be foot high , and the pipe eg to be as much . i assert then thirdly , the pillar of air cd to weigh pound , which i prove as before . all the parts of the same surface , are burdened with the like weight , but the part a sustains pound , therefore the part c must support as much . the connexion is evident , and the antecedent is so too , because the vvater ab being foot high , and six inches thick , must weigh pound : for , if inches , weigh seven pound , inches , must weigh pound . i assert fourthly , the pillar of air fh to weigh pound , which i demonstrat by the former medium . all the parts of a fluid that ly in the same horizontal surface , are equally prest ; but so it is , that e and f , do so ly ; therefore f must be as much burdened as e ▪ the water therefore eg , weighing pound , the air fh , must weigh as much . for if inches of water weigh seven pound , inches ( for so many are in the water eg ) must weigh pound . let us suppose secondly , the tub ab to be only inches high , and the tub eg , of the same hight , and that six inches wide , and this inches wide . i affirm then fifthly , the air cd to weigh yet pound , and the air fh , to weigh pound . because the pillar of mercury ab , weighs pound , and the pillar of mercury eg , weighs pound : therefore , if ab be , cd must be as much . and if eg be ; fh , must be of the same weight . i prove the mercury ab to weigh about pound , though it be but inches high ; because it is times heavier then water . for the same cause , doth the mercury eg weigh about pound . i say about , because foot , containes inches , more than times . let it be supposed thirdly , the pipe eg , ( being foot high , ) to have the one half of it ig , full of air , and the other half ek full of vvater , i affirm then sixthly , the part e , and the part f , to be yet equally burdened . that 's to say , the vvater ek , that 's now but foot , makes as great a pressure upon e , as when it was foot . the reason of this , is surely the pressure of the air ig , that bears down the water ke , with the weight of pound , the half of pound . if it be said according to the theorem , that there is as much pressure and weight in the least part of a fluid , as in the whole ; therefore the air ig , must be as heavy as eh . i answer ig , is not so heavy as fh , because the water ek impending in the lower part of the tub , hath occasioned the air ig , to expand it self so many inches , by which means , it loseth so many degrees of it's bensil . if you remove the water ek , then will the air ig , be as heavy , as fh ; because ek being air , it reduceth ig to that same degree of bensil with it self ; but when the air e is burdened with the water ek , it cannot make the air ig , of that same weight with it self . let us suppose fourthly , that only eight foot and an half of water , are in the tub , namely between e and n. i say then seventhly , that the part e , is as much burdened with it , as when the pipe was full ; because the foot , and an half of air ng , is exactly as heavy , as the . foot and an half of the water that 's gone . i prove it thus . the air e hath the weight of pound in it self , seing the weight of the surface , is alwayes equal to the weight of the pillar , but being burdened with the vvater en , that weighs pound , it cannot press up with more weight then with pound : and therefore the top of the water n , must press upon the under part of the air , that 's contiguous with it , with . if this be , the air ng , must press down with as much , seing according to the theorem , it is impossible , that one part of a fluid , can be under pressure , unless the next adjacent part , be under the same degree of pressure . therefore i conclude , that the foot and an half of air ng , is as heavy , as the foot and an half of the water that 's gone . this makes it evident also , that when the pipe is half full of vvater , as ek , the air ig , hath the weight of pound . because e being in it self , but being burdened with ek , it cannot make the top of the water k , press upon i with more weight than ; and therefore ( by the theorem , ) the air gi , must weigh likewise . i affirm eighthly , that , when the pipe is full of water ▪ from e to g , if a man poise it in his hand , he doth not find the weight of the water eg . and the reason is , because it 's sustained by the part of the surface e. but if the air e sustain it , my hand cannot sustain it . i find then only the weight of the tub , but not the weight of the vvater within it . i say ninthly , that when i poise the said tub , i find the whole weight of the pillar of air lm , which is exactly pound . i prove it thus . the pondus of a fluid is then only found , when there is not a potentia to counterpoise it , or at least , when the potentia is inferior to the pondus : but there is here no potentia , counterpoising the pondus of the air lm . therefore , i must find the weight of it , when i lift up the tub. the major proposition is clear from the tenth theorem . it 's evident also , from common experience ; for while a ballance is hanging upon a nail , with six pound in the one scale , and nothing in the other , you will find the whole burden , if you press up that one scale with the palm of your hand . but if so be , there were six pound in the opposite scale , you will not find the first six ; and the reason is , because it is in equilibrio with other six . 't is just so here , i must find the weight of the air lm , while i poise the tub , because it wants a weight to counterballance it . i prove the minor proposition thus . if any thing counterballance the air lm , it must either be the air below , namely the part e ; or the water eg : but neither of the twain can do it . not the air e , because it hath as great a burden upon it , as it is able to support , namely the water eg , that weighs pound . and for this cause , not the vvater it self , seing all the force it can have to counterballance lm , is from the surface of air e ; but this is in equilibrio with it already . i said that the air lm , was exactly pound weight . this also is evident , because it is just of these same dimensions , with the air fh . if it be said , the air lm must be thicker ; seing it's equal to the tub without ; but the air fh , is only equal to the tub within . i answer , it is so indeed ; but here is a solution to the difficulty . i do not find the whole weight of the air lm , but only as much of it , as is equal to fh . suppose the tub to be inches within , from side to side , and without , from side to side . i say then , i find only the burden of so much air , as answers to the cavity of the tub , because the rest of these inches , are counterpoised , by as much below , namely by the air , that environs the orifice e : for it 's supposed , that if the tub be two inches thick above , it must be as thick in the lips . so that the whole tub , is not unequally prest , but only so much of it within upon the top , as answers to the cavity . tenthly , that when the pipe is but half full of vvater , namely from e to k , i find only pound of the air lm , though before i found . the reason is , because the one half of it is now counterpoised by the air ig , and therefore the weight of it becomes insensible . 't is clear from the sixth assertion , that the air ig , presseth down with ; therefore it must press up with as much , seing according to the sixth theorem , the pressure of a fluid is on every side . eleventhly , that when there is only eight foot of vvater and a half in the tub , namely between e and n , i find only pound of the air lm . because in this case , the air ng counterpoiseth pound of it . for if the said air , burden the water ne , with pound , as is clear from the seventh assertion , it must likewise press up the tub with as much , and so counterpoise as much of the air lm . twelfthly , that when there is nothing within the pipe but air , the whole weight of the air lm becomes insensible to me . the reason is evident , because it is wholly counterpoised by the air within the pipe. i affirm thirteenthly , that the vvater eg , is in equilibrio with the water ab : that 's to say pound , is in equilibrio with pound . i prove it evidently , by the first medium ; all the parts of an horizontal surface , are equally prest ; therefore the part a , sustains no more burden , then the part e , therefore ab , is as heavy as eg , and consequently , the air cd , must be as heavy , as the air fh . lest this proposition may seem to contradict what is already said , i must distinguish a twofold ballance , according to the third theorem , one natural , another artificial . in the artificial ballance , where magnitudes do weigh according to all their dimensions , viz. longitude , latitude , and profundity , the water ab , and the water eg , are not in equilibrio together , seing the one is pound heavier than the other . but in the ballance of nature , such as these pipes are , all the four makes an equipondium together ; because they do not weigh here , according to their thickness , but only according to their altitude . therefore seing ab is as high as eg , and seing cd is as high as fh , they must all be of the same weight . from the first assertion i infer , that one and the same fluid , even in the ballance of nature , may sometimes be in equilibrio with a lesser weight , and sometimes with a greater , because the air cd , that weighs really pound , is in equilibrio with the water ab , that weighs but . this is , when ab is supposed to be only foot high . it 's likewise in equilibrio with it , when it s foot high . but how can ab , that 's foot high , press a , with as much weight , as when it s foot high ? i answer by a similitude , when a cylinder of wood foot high stands upon a table , it may burden it as much , as if it were a cylinder foot high . for , supposing it to be thrust in , between it , and v. g. the ceiling of the room above , it must press down with more weight , then if it were not thrust in . so , this cylinder of water ab , that 's but foot high , being prest between the surface a , and the top of the tub within , must burden a , as much , as if it were foot high ; for being of this hight , it only stands upon the surface , without pressing up the top of the tub. i infer from the second assertion , that each pillar in a fluid hath a determinate weight . this is evident from the determinate weight of ab , that weighs first pound , being foot high , and pound , being foot high , and so of the rest . i infer secondly , that the thicker , and grosser a pillar of a fluid be , it is the heavier , ( even in the artificial ballance ) and contrariwise , the more slender and thinner it be , it is the lighter . this is evident from the water ab , six inches thick , that weighs pound , and from the water eg , inches thick , that weighs pound . so doth the pillar of air cd , weigh less , then the pillar fh . here is ground for knowing the certain and determinate weight of a pillar , in any sort of a fluid whatsoever . as to air , its clear and evident , that a four-square pillar thereof , inches every way , weighs . that 's to say , if it were possible , to take the pillar of air fh , in its whole length , from the surface of the earth , to the top of the atmosphere , and pour it into the scale of a ballance , it would be exactly the weight of pound . here is a secret : though that same pillar of air , were no longer , than or foot , yet the pressure of it , upon the body , it rests upon , is equivalent to pound . if this be , ( you say ) what is the weight of air , that rests upon this table , that 's inches square ? i answer , it must be as heavy , as a pillar of water foot high , and inches thick , which will , by just reckoning , amount to pound , or to stone weight . it may be inquired next , what 's the weight of the air , that burdens the pavement of this parlour , that 's foot square ? i answer pound . because it is exactly the weight of a bulk of water foot high , and foot thick . 't is to be remembred , that though the pressure of it , be so much , yet being poured into the scale of a ballance , it will not weigh so much : for not only as much as fills the room must be taken , but as much as passeth from the pavement to the top of the atmosphere . according to this method 't is easie to determine the weight of any pillar of air whatsoever , provided a man but once know the thickness of it , both the wayes , e. g. there 's a planum inches long , and six inches broad , upon which rests a pillar of air. the weight of it then is , just the burden of a magnitude of water foot in hight , inches in length , and six inches in breadth . though the weight of any pillar of air may be known , by knowing only the dimensions of it , in breadth and length ; yet the weight of a pillar of water cannot be known , unless all the three common dimensions of it , be first known . the reason is this , the pillars of air , are all of the same hight , but the pillars of water in the ocean , are of different hights : therefore , not only must they be known , secundum longitudinem , & latitudinem , in length and breadth , but secundum profunditatem , that is , according to deepness . 't is easie to know then , what each particular pillar weighs . first then , try how much weight is in a cubical foot of water , and having found this to be v. g. pound , you may determine , that a pillar of water foot high , and inches thick , weighs pound . a pillar foot high , and six inches thick weighs pound . note , that in a cube of water six inches thick , there are inches , which weighs seven pound . in a pillar inches thick , and fathom , or foot high , you will find pound weight . in one , of the same thickness , but fathom high , there are , fifty six thousand pound weight . in a pillar three foot square , and fathom deep , there are , fifty thousand , and four hundred pound weight . make it fathom high with that thickness , and it will weigh , five hundred and four thousand pound . but , if according to the theorem , you consider ▪ the weight of the air above , it will weigh , five hundred , twenty and one thousand , one hundred thirty and six pound . a pillar foot square , and fathom deep , weighs , twelve million , ninety and six thousand pound , lastly suppose there were a bulk of water fathom deep , and fathom thick , such a magnitude would weigh . eight thousand seven hundred , and fifty million of pounds . but if the pressure of the air , that rests upon a surface of water fathom in breadth and length , be taken in , that weighs , a hundred and nineteen million of pounds , the total , that the bottom of the sea sustains , must be , eight thousand , nine hundred and fourty million of pounds ▪ or five hundred fifty and eight million , seven hundred , and fifty thousand stone weight . i infer from the fifth assertion , that the lightest of fluids may be brought to an equilibrium with the heaviest . for though mercury be times heavier than air , yet the part of the surface a , is no more prest with the mercury ab , then the part c is prest with the air cd . secondly , that inches of mercury , are of the same weight with foot of water . thirdly , the heavier a fluid be naturally , it hath the less altitude in the natural ballance ; and contrariwise , the lighter it be , it hath the more altitude . this is clear from the mercury , that 's inches , the water that 's foot , and the air , that 's counted fathom . i infer from the sixth assertion , that two fluids of different gravities , may make an equilibrium with a third of the same kind . because the foot of air ig , and the foot of water ek , are in equilibrio with the air fh . i infer secondly , that foot of air , may be as heavy as foot of water , because the air ig , is exactly as heavy , as the water ek . i infer thirdly , that the bensil of a fluid , is a thing really distinct , from the natural weight of it : because the pressure of the air ig , is pound ; but the natural weight of it will not exceed , if it were weighed in a ballance , two or three ounces . i infer fourthly , that air cannot suffer dilatation , but it must lose of it's pressure . because the air ig , that ought to weigh pound , weighs only . for understanding this , you must know , that when a pipe is about half full of air , and half full of water , and inverted , so much of the water falls out , and consequently so many inches doth the air above it , expand it self . so to make this pipe that 's foot high , half full of air and half full of water , you must pour in about foot of water , and the foot of air that 's in it besides , will , when the pipe is inverted , go up and expand it self to foot , two foot of water falling out . i infer from the seventh assertion , that when there are two fluids of different gravities , and weights counterpoising a third , by what proportion the one grows lighter , by that same proportion the other becomes heavier . for , when the vvater ek , that weighs pound , becomes en , that weighs , the air above it , that weighed , becomes now pound . i infer from the eighth , that the pondus of a fluid , cannot be counterpoised , by two distinct powers . because the foot of water eg , cannot be both sustained , by the part of the surface of air e , and my hand . i infer from the ninth , that the pressure and weight of a fluid , may be found , even in its own element , by sense . because in poising of the tub , i find the weight of the air lm . i infer secondly , that the weight of a fluid is only found in its own element , when there is not a potentia to counterpoise the pondus of it , because i find only the weight of the air lm , because it wants a potentia to counterpoise it . i infer thirdly , that it is very possible even in the artificial ballance , to weigh a fluid in its own element , and to know the precise weight of it , to a grain . for this cause , take a small chord , and fasten therewith the top of the pipe g , to the scale of a ballance , and the lead or stone that makes the counterpoise in the opposite scale , is the just weight of the air lm . i infer from the tenth , that by how much the nearer , the potentia of a fluid , comes to the pondus , by so much the less , is the pondus found , or is sensible . this is clear , because i find less of the weight of the air lm , it being counterpoised with the air ig , than before . this follows likewise from the eleventh assertion . i infer from the twelfth , that when the pondus of a fluid , is counterpoised , by an equal potentia , it becomes altogether insensible . i infer from the last , that two fluids differing in weight , according to the libra or artificial ballance , may agree in weight , according to the natural ballance . i infer secondly , that fluids in the ballance of nature , do not counterpoise one another according to their thickness , but only according to their altitude . fig. ●● pag. ● fig. pag. fig. . pag. fig. pag. an accompt of miscellany observations , lately made , by the author of the foregoing experiments . observation i. in may , there was need of a new sink , on the east side of tranent , for winning of coals . but while the coal-hewers were in digging down , and had come the deepness of or fathom , they were stopped from working by damps , or ill air , that flowed out plentifully from the sides of the sink , wherein there were a great number of cutters , or rifts , out of which that ill air came . to try the nature and power of damps , i took a dog , and fastned him in a bucket , with a small roap , that he might not leap over , and when he had gone down or fathom , he presently begins to howl , and cry pitifully , as if he had been beaten sore with a rod , and a little after , he begins to stagger , and his feet failing him , he falls down , as one overtaken with the epilepsy , and in going down to the bottom , his eyes turning in his head , they appeared very shining and clear like two large bright diamonds . fearing , that the damp should have killed him out of hand , he was instantly pulled up from the bottom , where he had not tarried seconds of time . and when the bucket had come to the mouth of the sink , he was pulled out , and laid upon the ground , to get fresh air. when he had lien a while as dead , he begins at last to gape , and gasp , and make some respirations , as if he had been rather expiring , than recovering . next , he began to stir and move his feet , and after , to raise himself upon his knees , his head staggering and wavering from side to side . after a minut or two , he was able to stand upon his feet , but so weakly , that he was not in capacity to walk or run . yet at last , being much refreshed , he escaped from us , and ran home , but slowly . in the afternoon , the same experiment was repeated , with another dog , whose case was the same in all things . but after he was perfectly recovered , for a further trial , we let him down the second time , and suffered him to tarry in the bottom of the sink , about the space of three minuts : but when he was pulled up , and taken out , we found no symptomes of life in him ; and so after half an hour and more , his body began to swell , which ordinarily befalls such , who are killed after this manner . after this , we sent down in the bucket , a little chicken , which , when it came near the damp , presently slapped with the wings , and falling down , turned over and over for a pretty while , as if it had been taken with a vertigo , or giddiness . but by drawing up the bucket in haste , and bringing the bird to the fresh air , it recovered . in the evening , we let down a lighted candle , but it was soon extinguished , when it came near mid-sink ; for here , rather than in the bottom , was the strongest damp. lastly , we let down by a chord , a brand-iron , with burning coals , whose flame was soon put out , and after a little while , we perceived the red coals to be extinguished by degrees ; yet not totally , because , as the coal-hewers observed , the power of the damp was not so strong , as before . these damps then have their ebbings and flowings , which seem to depend upon the weather , or rather upon the situation of the winds , and their force . for 't is observed , that a high south-west wind causeth ill air in this place ; and that , by reason of much wast ground , that lies upon the south , and south-west hand of this sink , whence are conveyed under ground by secret passages , which are nothing else but so many rifts and openings , commonly called by the coal-hewers , cutters , corrupted and rotten air , full of sulphurious stems . the reason why these passages are open , and replenished with nothing , but corrupted air , is this , the water , that 's ordinarily called the blood of the coal , being withdrawn with subterraneous gutters ( commonly called levels ) that are digged , and wrought under ground , sometimes a very long way , for drying of the mines , and the veins of the earth being now empty , there succeeds air ; which air , by process of time , and long standing , rots , and contracts a sulphurious quality , which causeth sudden death . now , when the wind is high , and strong from the south or south-west , that sulphurious air is driven through the ground ▪ and coming to sinks and mines , where men are working , presently infects the place , and hinders the work . 't is often observed , that the wind and air under ground , keep a correspondence in their motion , with the wind above ground : and therefore , when the wind is in such a point above , 't is found , that the motion of the air below runs such a way , and the contrary way , when the wind above ground , is in the opposite point . when there is a free passage between the bottom of the two sinks , you may observe the wind come down through the one , and running alongst under the ground , rise up thorow the other , even as water runs thorow a siphon . for this cause , when the coal-hewers have done with such a sink , they do not use to stop it , or close it up , but leaves it standing open , that the air under ground may be kept under a perpetual motion and stirring , which to them is a great advantage . 't is very strange to see sometimes , how much air , and how fresh it will be , even at a very great distance , namely four or five hundred pace , from the mouth of the sink . this could never be , unless there were a considerable pressure and weight in it , whereby it is driven forward , thorow so many labyrinths . and even in the utmost room , where the coal-hewers are working , the pressure is as great , as it is above ground , which is found by the torricellian experiment . in such a case , the air cannot press down thorow the earth and metalls , therefore the mercury must be suspended , not by a pillar from the atmosphere , but by the bensil of it . nay , put the case , that the whole element of air were destroyed , and this remaining , yet would it be able to support inches . to shut up this discourse , it is observed by the coal-hewers , that when there is ill air in a sink , a man may perceive distinctly , what is lying in the bottom , so clear and transparent is the air of it : but when the damp is gone , the medium is not so clear . in temperat and cold weather , the damps are not so frequent . from this sink , in soft winds , or in northerly winds , or when it blows from east or north-east , the damps are driven away . observation ii. jupiter upon wednesday night , at eleven a clock , being of november , , had the following position with the stars of gemini . he was so near to the star c , that to appearance , the points of his rayes did touch it . this star by looking upon the material glob , is fixed in the very zodiack , and in the degree of cancer , and is the very navel of the following twine . the star a is castor . the star b is pollux . the star d , is fixed in the forefoot of the following twine . from this place he moved , with a retrograde motion , till he came to the of cancer , about the of february , , and from that time became direct in his motion , and so upon the of march , at a clock , he was in a right line with canis minor , and the brightest star in auriga , and was in a right line with the eastmost shoulder of orion , and castor in gemini , or with that star , when south-west , that 's highest , and west-most . observation iii. it is written in the history of the royal society , that such a member of it , whose name i have forgotten , hath found out , among many other curious inventions , this , namely a way for knowing the motion of the sun in seconds of time : but is not pleased to reveal the manner how . because such a device may be usefull in astronomy , and likewise for adjusting the pendulum clock , i shall therefore briefly shew , the manner and way how such a thing may be done , as i have tried it my self . i took an optick tub , about foot long , only with two convex-glasses in it , and did so place it in a dark room , by putting the one end , in which was the object-glass , without the window , and keeping the other within , that i caused the beams of the sun shine thorow it , which were received upon a white wall four or five foot from the tub. this image , which was perfectly round , and splendid , did move alongst the wall very quickly , so that in a minut of time , it did advance seven inches and a half , which will be the eight part of an inch in a second , a motion very sensible . now , this beam that came thorow the tub , and lighted upon the wall , would not have moved one inch in a minut , if it had wanted the two glasses ; for as they magnify , and seem to bring nearer the object , so they quicken the motion of it . in a word , by what proportion the object is made more , by that same proportion is the motion quickned . 't is to be observed , that the longer the tub be , the motion is the swifter : for as the longest tub doth ordinarily most magnify the object ; so doth it most quicken the motion . next , the farther distant the white wall is from the end of the tub , the larger is the image ; and contrariwise , the nearer it be , it is the less . thirdly , the farther the wall be from the end of the tub , the circumference of the image is the more confused , and the nearer it be , it is the more distinct . fourthly , the darker the room be , it is so much the better . lastly , this trial may be made with ordinary prospects , of a foot , two foot , or three foot long , which will really do the thing , but not so sensibly , unless the glasses be very good . as to the use of this device in astronomy , i shall not say much . but shall only mention what it may serve for in order to the pendulum clock . for this cause , let a man choise a convenient room , with a window to the south , wherein this tub may be so fixed , that it may ly just , or very near to the true meridian , and may move vertically upon an axil-tree , because of the suns declination every day . then at a certain distance from the end of it , fix and settle a large board of timber , smooth , and well plained , and well whited , for receiving the image . in the middle of this board , draw a circle with charcoal , equal in diameter to the circle of the image . now , this being done , you will find that assoon as the west side of the sun , begins to come near to the meridian , the image begins to appear upon the board , like the segment of a circle , and grows larger , and larger , till it become perfectly round . now in the very instant of time , wherein the image , and the circle are united , set the wheels of your clock a going , from the hour , minut , and second of xii . to morrow , or or dayes after , when you desire to make an examination , wait on about a clock , when the sun is coming to the meridian , and you will find what the difference is . if the clock go slow , observe , assoon as the image is united with the circle ( which you will perceive in a second of time ) the variation , that 's to say , how many seconds interveens between that second , wherein the union fell , and that second , that closes xii hours in the clock . if it go fast , observe how many seconds passes from that second , that ends xii hours , and that wherein the image of the sun is united with the circle , which if you do , you will know exactly , what the difference is , even to a second . but without this , you will find great difficulty to know the variation in or seconds , especially in a common dial. but here , you will see distinctly the image of the sun move every second of time , the eighth part , or the sixth part , or the fourth part of an inch , according to the length of your tub , and goodness of your glasses . 't is to be observed , that in adjusting the pendulum clock , respect must be had to the table of equation of dayes , commonly known in astronomy . for if this be not , it is impossible to make it go right , and that because all the natural dayes of the year , are not equal among themselves : that 's to say , the time that 's spent by the suns motion from the meridian this day , to the same meridian , the next day , is not equal , but is more or less , than the time spent betwixt meridian and meridian , a third or fourth day after . for instance , the sun this day being of iuly , comes sooner to the meridian by three seconds of time , than he came yesterday . within or dayes , ( suppose the of iuly ) he will be longer in coming to the meridian by seconds , than upon the . this difference i grant , in short time is not sensible , yet once in the year , it will amount to more than half an hour . this inequality of dayes arises from two-causes . first , from the suns eccentricity , whereby he moves slowlier in one part of the zodiack , than in another : for in summer when he is furthest from the earth , he goes slowlier back in the ecliptick , than in winter , when he is nearer to it . the second cause , which is truly the far greater , is this , because in the diurnal motion of the sun , equal parts of the aequator , does not answer to equal parts of the zodiack . hence it followes , that if the natural dayes be not equal among themselves , the hours must be unequal also : but this is not considerable . by help of such a tub placed in a dark room , it is easie , when the sun is under eclipse , to enumerat distinctly the digits eclipsed . likewise , if you take out the object glass , and cover a hole in the window board with it , you shall see distinctly upon a white wall , the species and true representations of all objects without . and by comparing the quantity of the object without , with the quantity of it within , you may know the distance of it from the window , though it were many miles . for as the one quantity , is to the other , so is the distance between the glass and the object on the wall , to the distance between the glass and the object without . it may be inquired whether or not , the retrograde , as well as the diurnal motion of any of the planets , may be discerned , in minuts or seconds , by the help of a long telescope ? in answer to this , we must suppose the planets only to have a retrograde motion , and consequently to move slowly from west to east , saturn once in years , or , to run about the zodiack ; iupiter in , mars in years , the sun in one year , venus and mercury in less time , and lastly the moon in a moneth . now i say , it is impossible by the longest tub , that the greatest artist can make , to discern the motion of the inferior planets , far less the motion of the superior , either in minuts or in seconds , and that by reason of the great tardity , and slowness of the motion . notwithstanding of this , i am induced to think , that the retrograde motion of the moon might be discerned , at least in minuts . for evincing of this , let us suppose which is true , that the sun runs from east to west half a degree in two minuts of time , seing in an hour he runs degrees . next , that the moon goes about the zodiack in dayes and hours , namely from that same point , to that point again , and consequently runs back every day degrees and about minuts . by this account , she must retrograde half a degree , and about minuts of a degree every hour . the sun then runs half a degree in two minuts , and the moon half a degree in minuts ; therefore the moon must be times slower in her retrograde motion , than the sun is in his diurnal motion . let us suppose next , as i observed with a tub foot long , that the image of the sun runs the eighth part of an inch every second , and consequently , seven inches and an half , in a minut : then must the image of the moon with that same telescope , run the thirtieth part of seven inches and a half in a minut , seing she runs times slowlier ; therefore in every minut of time she must advance the fourth part of an inch , which will be very sensible . though we grant , that the moon hath no retrograde motion properly , yet by comparing the diurnal motion of the moon , that 's slower , to the diurnal motion of the sun , that 's swifter , we shall really find the thing it self . therefore in the time of a solar eclipse , this retrograde motion is conspicuous , which by an ordinary telescope may be discerned in minuts . assoon then as the east side of the moon , begins to enter upon the west side of the sun ( the greater the eclipse be , it is the better ) observe , and you will find the one image , which will be black , cover the other by degrees , that 's splendid , and run in every minut of time , the fourth part of an inch of the suns diameter , provided alwayes , that the sun run the eighth part of an inch in a second . observation iv : upon tuesday the . of iuly , the following experiment was made . in the middle marches between scotland and england , there is a long tract of hills , that run from flowdon , many miles south and south-west , amongst the which , the mountain cheviot is famous beyond , and conspicuous above all the rest for altitude , from whose top a man may discern with one turning of his eye , the whole sea-coast from new-castle to berwick , much of northumberland , and very many leagues into the great german ocean : the whole mers and teviotdale , from the foot of tweed , to very near the head of it : lauderdale , and lammer-moor , and pentland hills above edinburgh . the north side of this mountain is pretty steep , yet easie to climb , either with men or horse . the top is spacious , large and broad , and all covered with a flow-moss , which runs very many miles south . when a man rides over it , it rises and falls . 't is easie to thrust a lance over the head in it . the sides of this hill abounds with excellent well-springs , which are the original of several torrents , amongst the which colledge-water is famous , upon which , not a mile from the foot of this mountain is white-hall . the adjacent hills are for the most part green , and excellent for the pasturage of cattel . not many years ago , the whole valleys near the foot of cheviot , were forrests abounding with wild-deer . upon the highest part of this mountain was erected the torricellian experiment for weighing of the air , where we found the altitude of the mercurial cylinder inches and an half . the air was dry and clear , and no wind . in our valley-countreys , near to the sea-coast , in such weather , we find the altitude inches and an half . when this difference was found , care was taken to seal up closly with bee-wax , mixed with turpentine , the orifice of the vessel , that contained the stagnant mercury , and thorow which the end of the pipe went down . this being done with as great exactness as could be , it was carried to the foot of the mountain in a frame of wood , made on purpose , and there opening the mouth of the vessel , we found the mercury to rise an inch and a quarter higher than it was . the reason of this strange phenomenon must be this , namely a greater pressure of the air at the foot of the hill , than upon the top : even as there is a greater pressure of water in a surface fathom deep , than in a surface fathom deep . 't is not to be doubted ▪ but if the root of the mountain had been as low as the sea coast , or as the surface of tweed at kelso , the mercurial cylinder would have been higher . this way of observing , seems to be better than the common : for while the baroscope is carried up and down the hill , without stopping the orifice of the vessel , that contains the stagnant mercury , the cylinder makes such reciprocations , by the agitation of a mans body , that sometimes abundance of air is seen to ascend up thorow the pipe , which in effect makes the cylinder shorter than it ought to be . but if so be , the end of the pipe be immerged among quick-silver , contained in a glass with a narrow orifice , so that it may be stopped compleatly , you will find no reciprocations at all . and to make all things the more sure , the glass may be filled up either with mercury , or with water above the mercury ; by which means the cylinder in the down-coming , or in the up-going shall remain immoveable . besides the stopping of the orifice of the said glass , you may have a wider vessel , that may receive the same glass into it , and it being full of water , may so cover the sealed orifice , that there shall be no hazard of any air coming in . or this experiment may be first tried at the root of the hill , and having stopped compleatly the mouth of the vessel , the whole engine may be carried up to the top , where you will find the mercury subside and fall down so much ; namely after the said orifice is opened : for as the stopping of the orifice at the root of the hill , is the cause , why that same degree of pressure remains in the stagnant liquor ; so the opening of it upon the top of the hill , is the cause why it becomes less . this experiment lets us see , that the pressure of the air seems to be as the pressure of the water , namely the further down the greater ; and the further up the less : and therefore , as by coming up to the top of the water , there is no more pressure , so by coming up to the top of the air , there is no more weight in it ; which in effect sayes , that the air hath a determinat hight , as the water hath . from this experiment we cannot learn the determinat hight of the air , because the definit hight of the mountain is not known . i know there are some , who think that the air is indefinitly extended , as if forsooth , the firmament of fixed stars were the limits of it , but i suppose it is hard to make it out . observation v. june . . i observed the sun within minuts of setting , to have a perfect oval figure , the two ends lying level with the horizon . his colour was not red as ordinarily , but bright and clear , as if he had been in the meridian : neither was the sky red , but clear also . and by the help of the pendulum clock , i have observed his body to be longer in setting than it ought , by eight minuts , and sometimes by ten , and his diameter longer in going out of sight than it ought , by two , and sometimes by three minuts . the reason of these phenomena , must be the refraction unquestionably . observation vi. upon saturday evening the of iuly , and the night following , till about two a clock in the sabbath morning , there fell out a considerable rain , with great thunder , and many lightnings . about sun-set , the convocation of black clouds appeared first towards the horizon in the south-west , with several lightnings ; and the wind blowing from that point , carried the clouds and rain over mid and east-lothian , towards the firth and sea-coast . about a clock , the whole heavens almost were covered with dark clouds , yet the rain was not very great , neither were the thunder claps frequent , but every fifth or sixth second of time , a large and great lightning brake out . but before the thunder crack was heard , which happened every fourth o● fifth minut , the lightning was so terrible for greatness , and brightness , that it might have bred astonishment . and because the night was very dark , and the lightning very splendid , a man might have perceived houses and corn-fields at a great distance . and if any had resolved to catch it , in the breaking out , it did so dazle the eyes , that for half a minut , he was not able to see any thing about him . sometimes the lightning that went before the thunder , brake forth from the clouds , like a long spout of fire , or rather like a long flame raised high , with a smiths bellow● , but did not continue long in sight . such an one above the fi●th was seen to spout downward upon the sea. sometimes there appeared from the one end of the cloud to the other , an hiatus , or wide opening , all full of fire , in form of a long surrow , or branch of a river , not straight , but crooked . i suppose the breadth of it , in it self , would have been twenty pace and more , and the length of it five or six hundred pace : the duration of it , would have been about a second of time . sometimes a man might have perceived the nether side of the cloud , before the crack came , all speckled with streams of fire , here and there , like the side of an hill , where moor-burn is , which brake forth into a lightning . but there was one , after which followed a terrible thunder crack , which far exceeded all the rest , for quantity and splendor . it brake out from the cloud , being shot from north to south , in form of fire from a great cannon , but in so great quantity , as if a gun ten foot wide , with pound weight of powder in it , had been fired . and surely the lightning behoved to be far greater in it self , seeing it appeared so great , at so great a distance . it did not evanish in an instant , like the fire of a gun , but continued about a second and an half ; by reason ( it seems ) that it could not break out all at once . this did so dazle the sight , that for half a minut almost , nothing was seen , but like a white mist flying before the eyes . the whole countrey about was seen distinctly . all these great lightnings were seen a considerable time , before the crack was heard . sometimes seconds numbered by the pendulum clock interveened , namely when the thunder was at a distance , about or miles . sometimes or only interveened . but when the thunder was just above our head , no moe passed , than or , which seems to demonstrat , that these thick black clouds , out of which the thunder breaks , are not a scottish mile from the earth , when they are directly above us . 't is observable , that in all lightnings , and thunderings , there is no smoke to be seen , which seems to evince , that the matter whereof they are generated , must be most pure , and subtil . who knows , but this countrey , that abounds with coal , may occasion more thunder and lightnings , than other places , namely by sending up sulphurious exhalations to the middle region of the air , wherewith the coal-mines abound . observation vii . this is a method for finding out the true south and north points , which are in effect very difficult to know . take therefore four pieces of timber , each one of them five foot long , and about six inches thick , square-wise . sharpen their ends , and fix them so in the ground , that they may stand perpendicular , and as near to south and north , by a magnetick needle , as may be . the place would be free of trees , or of any such impediment , that it may have a free prospect of the heavens . as for their distance one from another , let the two north-most , and the south-most be two foot asunder : let the two east-most , and two west-most , be but one foot , making as they stand , an oblong quadrangle . for keeping them equidistant above , as well as below , take four bars of wood , about three inches broad , and one inch thick , and nail them round about upon the four sides , on each side one , so that being nailed on horizontally , they may make right angles , with the tops of the standards above . there are then for distinctions cause , the north-bar , and the south-bar , that runs east and west , and the east-bar , and the west-bar , that runs south and north , there is here no difficulty in the thing it self , but only in the fancy to conceive it . besides these four , there must be other four of the same form and fashion , nailed on arder down about the middle of the four standards . take next some small brass wyre strings , such as are used in virginals , and fix one from the middle of the south-bar , that 's upmost , to the middle of the south-bar just under it . fix it so , that it may be exactly perpendicular , which may be done , with a great weight of lead . take a second wyre string , and hang it plumb from the west end of the north-bar , and another from the east end of the same bar , i mean the bar that 's nearest to the top . these three strings so fixed , will go near to make an equilateral triangle . now because the device is for finding out the meridian by the stars in the night time , not by any indifferently , but by these that are nearest to the pole , therefore observe in iuly and august , when the guard-stars in the evening begin to come down towards the west , and keeping closs one eye , bring the other somewhat near to the south-most string , and order your sight so , that this string , and the west-most string upon the north side , may catch the foremost guard-star in the down-coming , when it is furthest west , and there fix it . when the same star is turning up towards the east , catch it by the south-most string , and the east-most string on the north side , and your work is done , if so be , you divide exactly , between the east-most and west-most , and there hang a fourth string , which with the string upon the south-side , gives you the true south and north. for better understanding , note first , that , when the guard-stars are coming down , or going up , the altitude varies quickly , but the azimuth , or motion from east to west , will not vary sometimes sensibly in two hours almost , which is a great advantage in this case . but when you find out the meridian with a plain , and a perpendicular stilus , by the shadow of the sun , if it be not when he is about east and west , the azimuth alters more than the altitude , wh●ch is a great disadvantage . now its certain , the slower the motion be from east to west of any star , it is the easier to observe , and it is the more sure way . note secondly , that special care must be had , to cause the strings hang perpendicular . note thirdly , that before you begin your observations , the south-most string must be made immoveable , but the east-most , and west-most , on the other side , must not be so , because as the stars in going about move from east to west , so must the said two strings be left at liberty , to move a little hither and thither , till the observations be ended . note fourthly , that assoon as you perceive sensibly , the foremost guard-star to decline towards the west , then you must begin to observe , which is nothing else , but to fix your eye so , that the south-most and west-most string , may cover the said star. and because in coming down , it goes west , therefore , let the west-most string move towards the left hand by degrees , following the star to its utmost , till it be covered by them both . follow the same method , in observing the same star in going up towards the east . note fifthly , that when you make the two strings cover the star , that which is nearest to the eye , will appear transparent , and of a larger size , so that you may perceive distinctly thorow it , not only the star it self , but the other string also , which is a great advantage . this is evident to any , who holds a bended silk threed between their eye and a star in the night time ; for when you direct your sight to the star , the string appears like the small string of a virginal when it trembles . note sixthly , that in observing in a dark night , you must have a cut-throat , that by the light of the candle you may perceive the strings . some other things might be noted , but you will find them better by experience , than they can be exprest here . i named iuly and august in the evening for observing the guard-stars , when they are west-most , but there are several other seasons , when this may be done as conveniently . they are east-most in the latter end of october , and beginning of november about or a clock in the morning . if a man were desirous to make this observation quickly , i suppose he might in the end of october , find the said stars west-most in the evening , and east-most the next morning . besides the guard-stars , a man may make use of the polar-star ; for as it goes higher , and lower than the true pole , by degrees and minuts , so it goes as much to the east , and as much to the west , once in hours . in the end of iuly , you will find the polar-star east-most , about a clock at night , and in the end of ianuary west-most at a clock . note , that every month , the fixed stars come sooner to the same place by two hours : therefore in the end of august the polar-star must be west , at a clock at night , and east at a clock in the morning . when the meridian is found out after this manner , there is no star or planet can pass it , but you may know exactly when , be it never so high , or never so low . for there is nothing to be done , but to wait , till the south-most and north-most string cover the body of the star. if it be the sun , hold up a white paper , behind the two strings , and when their shadows do co-incide , and are united , then is his center in the meridian . if the sun do not shine clear , as when he is under mist , or a thin cloud , you may exactly take him up in the meridian , with the two strings . this frame will serve as well , to know when any of the north stars comes south , or north , and consequently when they are highest , and when they are lowest : for being fixed in an open place of the orchard , there 's no celestial body can pass the meridian , either on the one side , or the other , but it may be catched , what ever the altitude be , and that most easily . observation viii . there hath been much inquiry made by some anent the reason , why the dead body of a man or beast , riseth from the ground of a water , after it hath been there three or four days . but though many have endeavoured to solve the question , yet the difficulty remains ; and in effect it cannot be answered , without the knowledge of the foregoing doctrine , anent the nature of fluid bodies . to find out the reason then of this phenomenon , consider , that all bodies , are either naturally heavier then water , as stone and lead , or naturally lighter , as wood and timber . if they be heavier , they sink : if they be lighter , they swim . now i say , a mans body immediatly after he is drowned , his belly being full of water , must go to the ground , because in this case , it will be found specifically or naturally heavier then water . that 's to say , a mans body , will be heavier , than as much water , as is the bulk of a mans body . for pleasing the fancy , imagine a statue to be composed of water , with all the true dimensions of the person that 's dead , so that the one shall answer most exactly to all the dimensions of the other . in this case , if you counterpoise them in a ballance , the real body , that 's made up of flesh , blood , and bones , shall weigh down the other . but after this dead body hath lien a short time among the water , it presently begins to swell , which is caused by the fermentation of the humors of the blood , which goeth before putrefaction , and after three or four dayes swells so great , that in effect , it becomes naturally lighter than water , and therefore riseth . that is to say , take that body , that is now swelled , and as much bulk of water , as will be the precise quantity of it , and having counterpoised them in a ballance , you will find the water heavier than the body . observation ix . upon thursday the of august , the following experiment was made in a new coal-sink , on the west side of tranent . when the coal-hewers had digged down about or fathom , they were interrupted sometimes with ill air : therefore to know the power and force of the damp , we let down within the bucket a dog. when he had gone down about fathom , or middle sink , we found little or no alteration in him , save only that he opened his mouth , and had some difficulty in breathing , which we perceived evidently : for no sooner he was pulled up to the top , where the good air was , but he left off his gaping . we let him down next to the bottom , where he tarried a pretty while , but no more change we found in him than before . after this we let down a great quantity of whins , well kindled with a bold flame , but they no sooner came to the middle of the sink , but the flame was in an instant extinguished : and no sooner was the bucket pulled up , but they took fire again . this was or times tried , with the same success . if we compare this observation with the first , we will find , that all damps are not of the same power and force ; but that some are stronger , and kills men and beasts in an instant : and that others are less efficacious , and more feeble , and doth not so much hurt , and that men may hazard to go down into a sink , where ill air is , even though fire be sometimes extinguished . we see next , that these damps doth not alwayes infect the whole air of a coal-pit , but only a certain quantity : for sometimes it is found in the bottom , sometimes in the middle . and we see lastly , that they are not alwayes of long continuance : for it is found , that though the air be ill in the morning , yet it may be good ere night ; and totally evanished ere the next day . we may add , as was noted in the first observation , that these damps depend much upon the scituation of the winds , seing in strong southerly winds , they are frequently in these places . observation x. of these many excellent devices , that have been found out of late , the air-pump is one , first invented in germany , and afterwards much perfected in england by that honourable person mr boyl , who for his pains , and industry in making experiments therewith , deserves the thanks of all learned persons . several trials hath been made of late by it , some whereof , are as follows . i took a slender glass-tub about inches long , closs above , and open below , and filled it with vvater . i next inverted it , and set the orifice of it , just upon the mouth of the brass-pipe , that bends upward thorow the board , whereon the receiver useth to stand , and cemented them together . at the first exsuction , the whole vvater in the pipe fell down , and ran thorow the brass-conduit to the pump . having for a short while stopped the passage , and thrust down the sucker , i next opened it again , and the pump being full of vvater , it was driven with a considerable force up thorow the pipe ; yet was it not compleatly fill'd as before , by reason of some air , that i saw in the top . after this was done , with pleasure five or six times , i opened the stop-cock more quickly , than i had used , but the vvater , by this means , was so furiously driven up thorow the tub , that in effect , it broke the end of it , that was hermetically sealed ; and the piece that flew off , did hit the seiling so smartly , that it rebounded a very far way . from this we see the reason , why vvater falls not down from vessels that have narrow necks , though they be inverted , because it 's kept in by the force and power of the environing air. 't is observable , that though this pipe had been foot high , yet the whole vvater in it would have subsided , and fallen down , with one exsuction . the next trial was with the help of a small receiver , which in effect was a real cupping-glass . this had a hole made in the bottom of it , and was cemented to the brass-plate , and the mouth of it looking upward , had a lid for covering of it . i took next the lately mentioned glass-pipe , and filled it with good brandy , and having drowned the end of it among stagnant brandy , i set the vessel wherein it was within the receiver , the pipe coming up thorow the lid , and having cemented it closly , i made the first exsuction , and found no descent of the liquor from the top of the tub. at the second , it fell down about an inch . at the third , it fell down four or five . but here appeared a great multitude of small bubbles of air , like broken vvater , near the top of the pipe within . and besides this phenomenon , there ascended from the stagnant liquor up thorow the pipe , an infinit number of small bubbles , no bigger than pin-heads , for a very large time . vvith a fourth exsuction , it fell down within two or three inches of the stagnant brandy . and thinking to make the one level with the other , i made a fifth ; but here appeared a strang effect , namely , not only the whole brandy in the pipe subsided , and was mingled with the stagnant brandy , but at this exsuction , there came a great quantity of air from the mouth of the pipe , and rose up thorow the stagnant liquor in bubbles . having made another exsuction , there came yet more air out , and so copiously , that i thought there had been some seak in the tub , through which the outward air had entered ; but knowing the contrary , i continued pumping a very long time , till i found less and less come out , and at length , after near exsuctions it ceased . this air to appearance , was so much as might have filled twenty tubs , every one of them as large , as the tub it came out of . and surely all of it came out from among the small quantity of brandy that filled the pipe , and that environed the mouth of it , i mean the stagnant brandy , both which would not have been eight spoonful . after this i opened the stop-cock leasurely to let in the air to the receiver ; then did the brandy climb up the pipe slowly , till it came near to the top , and there made some little halt , by reason of half an inch of air that appeared there . but more and more air coming into the receiver , that half inch in the top of the pipe , did so diminish , that it appeared no bigger than the point of a pin , and was scarcely discernable to the eyes . what a strange and wonderful faculty of dilatation and contraction must be in the air , seing that which presently had filled the whole tub , that was inches long , and the sixth part of an inch wide , was contracted to as little room , as the point of a needle . and by making some new exsuctions , that small atome of air did so dilate it self again , that it filled the same tub , and not only that , but , as formerly , it bubbled out from the mouth of the pipe several times . 't is to be observed , that though at the first falling down of the brandy , it appeared like broken water , near the top of the pipe within , yet no such thing was seen the second time it fell down ; the reason is , because by the first exsuctions , it was well exhausted of its aërial particles . once or twice i found , after the brandy within the pipe was well freed of air , that no exsuctions could make it move from the top of the tub ; and observed a round bubble of air to march up , which when once it came to the top , did separate the one from the other . if this hold good , it seems to prove , that neither mercury , nor any other liquor would fall down in pipes , unless there were air lurking amongst the parts to fill up the deserted space . from this experiment we learn , that no person can well apprehend or conceive , how far , and to what bounds the smallest part of air is able to expand it self . and it proves evidently , that when the receiver is as much emptied as it can be , by the art of man , yet it is full of air compleatly . the third trial was after this manner : i set within the receiver a little glass half full of brandy , and the lid being cemented on , i began to pump , but there appeared no alteration at the first exsuction . at the second , i perceived a great company of very small bubbles , that for a long time ascended from the body of it , and came to the surface . at the third , they were so frequent , and great , that the brandy appeared to seeth and boil , and by reason of the great ebullitions , much of it ran over the lips of the glass , and fell into the bottom of the receiver . this boiling continued for the space of or exsuctions , and by process of time , the bubbles grew fewer and fewer , and when about or exsuctions were made , no more appeared . with this same sort of brandy , i filled the fore-named pipe , and set it within the receiver , the mouth of the tub being guarded with the same sort of liquor . when it began to subside , there appeared no bubbles near the top as before : the rea●on seems to be , because the brandy was well exhausted from its aërial particles . for a fourth trial , i filled the same tub with ale , that was only or dayes old , and drowning the end of it among stagnant ale of the same kind , i began to pump , and found , that assoon as the liquor began to subside , from the top of the pipe , the whole ale within the pipe , almost turned into air , and froth , and so many large bubbles came up from the stagnant liquor , that i thought the whole was converted into air. it was most pleasant to behold their several forms and shapes , their order and motion . this same tub being filled with sweet milk , i found very few bubbles in it , when by the exsuctions , it began to subside . i likewise took a little glass-viol , and fill'd the half of it full with common ale , and set it within the receiver . at the first exsuction , bubbles of air began to rise out of it . at the second and third , they did so multiply , that they fill'd the other half of the glass , and ran over , as a pot doth when it boileth . and before i could exhaust all the air out of it , moe than exsuctions passed . for a fifth trial , i filled the often mentioned pipe with fountain-water , and when it began to subside by pumping , i found it leave much air behind it . but all the exsuctions i made , could not make the water of the pipe go so low , as the stagnant water , by which impediment , i could pump no air out of the pipe , as i did , while i made use of brandy . this tells us , that either there is not so much air lurking among water , as among brandy , or that the air among this , hath a more expansive faculty in it , than the air that lurks among water . if any think , that it is not true and real air , which comes from the brandy , but rather the spirits of it , which evaporats . i answer , if a man tast this brandy that 's exhausted of its aërial particles , he will find it as strong , as before , which could not be , if the spirits were gone , for a sixth trial , i took a frog and inclosed her within the receiver . but all the exsuctions i was able to make , could not so much as trouble her . only , when the receiver was exhausted , i perceived her sides to swell very big , and when the stop-cock was turned , to let in the air again , her sides clapped closs together . i observed likewise , when the air was pretty well pumped out , that the frog had no respirations , or if there were any , they were very insensible . the next day , after she had been prisoner in the receiver hours , i began again to pump , and after several exsuctions , her sides swell'd pretty great , and i perceived her open her mouth wide , and somewhat like a bag endeavouring to come out , which surely hath been some of her noble parts , striving to dilate themselves , the body being freed of all pressure from the ambient air. observation xi . take a slender chord , about or yards in length , and fasten the middle of it to the seiling of a room with a nail , so that the two ends of it may hang down equally . take next a piece of wood , two or three foot long , two inches broad , and one inch thick , and boring an hole in each end of it , put through the two ends of the chord , and fasten them with knots ; but so , that the piece of wood may ly horizontal , and be in a manner a pendulum to swing from the one end of the chamber to the other . take next a bullet of lead or iron , about or ounces , and lay it upon the said piece of wood : but because it cannot well ly , without falling off , therefore nail upon the ends , and the sides of the timber , four pieces of sticks , on each end one , and on each side one , as ledgets , for keeping the bullet from falling off . all things being thus ordered , draw up the piece of wood towards the one side of the room , by which means losing its horizontal position , it will ly declining-wise , like the roof of an house . in this position , lay the iron bullet in the upmost end of it , and then let them both pass from your fingers , the one end of the wood going foremost , and you will find it swing towards the other side of the house , and return again , as a pendulum . this motion , if the wood be well guided in its vibrations , will last perpetually , because in its moving down , the bullet is hurled from the one end of the wood , to the other , and hits it so smartly , that it begets in it , an impulse , whereby it is carried farder up , than it would be , without it . by this means , the vibrations get not liberty to diminish , but all of them are kept of the same length . in the second vibration , the same bullet is hurled back again to the other end , and hiting it with all its weight , creats a second impulse , wherewith the wood is carried , as far up as the point it was first demitted from . though this may seem a pretty device to please the fancy , that 's many times deceived , while things are presented to it , by way of speculation , yet upon tryal and experience , there will be found , an unspeakeable difficulty : and it 's such an one , that a man would not readily think upon . i said , that when the wood was let go , and was in passing down , the bullet in it , would hurl down , and hit the oppsite end , and beget an impulse ; but there is no such thing , for verily , though the bullet be laid upon a very declining plain board , whereupon no man could imagine a round body could ly , yet all the time the board is in swinging , from the one side of the chamber , to the other , and consequently , sometimes under an horizontal , and somtimes under an declining position , the bullet lies dead in the place , where you first placed it . this observation is not so much for a perpetual motion , as for finding out the reason of this pretty phenomenon , namely , what 's the cause , why the bullet , that cannot ly upon a reclining board , while it 's without motion , shall now ly upon it , while it 's under motion ? what is more difficult , and nice , to ly upon any thing , that declines from a levell , than quick-silver ; yet lay never so much of it upon this board , while it is swinging , it shall ly dead , and without motion . but no sooner you stop the motion of the wood , but assoon , the bullet , or the quick-silver , is hurled , either this way , or that way . observation xii . i find it mentioned by some learned persons , that when a ship is under sail , if a stone be demitted from the top of the mast , it will move down in a line parallel with it , and fall at the root . some might think , it ought not to fall directly above the place it hang over , but rather some distance behind , seing the ship hath advanced so much bounds , in the time , wherein the stone is coming down . likewise , while a ship is under sail , let a man throw up a stone never so high , and never so perpendicular , as to his apprehension , yet it will fall down directly upon his head again , notwithstanding that the ship hath run ( perhaps ) her own length in the time , while the stone was ascending and descending . this experiment i find to hold true , which may be easily tryed , especially when a man is carried in a boat upon smooth water , drawn by a horse , as is done in some places abroad . let him therefore throw up a little stone , or any heavy body , and he will find it descend just upon his head , notwithstanding that the horse that draggs the boat , be under a gallop , and by this means hath advanced ten or twelve paces in the time . or while the boat is thus running , let a man throw a stone towards the brink of the vvater ; in this case he shall not hit the place he aimed at , but some other place more forward . this lets us see , that when a gun is fired in a ship under sail , the bullet cannot hit the place it was directed to . neither can a man riding with a full career , and shooting a pistol , hit the person he aims at , but must surely miss him , notwithstanding , that though in the very instant of time wherein he fires , the mouth of the pistol was most justly directed . for remedy whereof , allowance must be granted in the aiming at the mark . vvhile a man throws up a stone in a ship under sail , it must receive two distinct impulses , one from the hand , whereby it is carried upward , the other from the ship , whereby it is carried forward . by this means , the stone in going up , and coming down , cannot describe a perpendicular , but a crooked line , either a parabola , or a line very like unto it . neither can it describe a perpendicular line , in coming down from the top of the mast , though in appearance it seem to do so , but a crooked one , which in effect must be the half of that , which it describes in going up , and coming down . for this same cause , a stone thrown horizontally , or towards the brink of the vvater , must describe a crooked line also . and a pistol bullet shot , while a man is riding at a full carreer , must describe a line of the same kind . note , that a man walking from the stern of a ship to the head , walks a longer way , than in walking from the head to the stern . secondly , a man may walk from the head to the stern , and yet not change his place . 't is observable , that a man under board , will not perceive whether the ship be sailing , or not , and cannot know when her head goes about . and it is strange , that when a man is inclosed in a hogs-head , though he have light with him , yet let him be never so oft whirled about , he shall not know , whether he be going about , or not . observation xiii . i found in a philosophical transaction lately printed , that decemb. . , one doctor beal found the mercury in the baroscope , never to be so high , as it was then . that same very day , i found the hight of it inches , and nine ten parts , which i never observed before . and though the day here was dark , and the heavens cove●ed with clouds , yet no rain for many dayes followed , but much dryness , and fair weather . on saturday night , march , , i found the altitude no more than , and nine ten parts . this night was exceeding windy , with a great rain . on february . . i found the altitude inches , and the heavens most clear . but in the most part of may following , i have found the hight but inches , and five ten parts , in which time there was abundance of rain . observation xiv . november . . i made exact trial , with the magnetick needle for knowing the variation , and i found it vary from the north , three degrees and a half , towards the west . hevelius writes from dantzick to the royal society at london , iuly . , that it varies with him seven degrees twenty minuts , west . observation xv. december . . , i observed with a large quadrant , half a clock at night , the formost guard-star , when it was in the meridian , and lowest , to have degrees minuts of altitude . and on ianuary . at a clock in the morning , i found it , when it was in the meridian , and highest , to have degrees , minuts hence i conclude the elevation of the pole here to be degrees , minuts , seconds : and consequently as much at edinburgh ; because both the places are upon one and the same parallel . observation xvi . for finding the true meridian , follow this method . in some convenient place fix two wyre strings with weights at them , that they may hang perpendicular . then in the night time , observe , when the fourth star of the plough begins to come near to the lowest part of the meridian , at which time you will find the polar star highest . then , so order the two strings , by moving them hither , and thither , till both of them cover both the said stars , then shall they in that position give you the true south and north. this observation is the product of the seventh . observation xvii . there fell out in mid and east-lothian , on thursday may , , in the afternoon , a considerable shour of hail , with thunder and rain . it came from the south-west , with a great blast of wind , and ran alongs from picts-land-hills north-east , towards the sea-coast . the hail were big in several places , as musquet ball , and many of them rather oval than round . some persons suffered great loss of their young pease ; others of their glass windows . eight or ten days before , there was a considerable heat , and dry vveather . for dayes after , cold easterly winds , with rain every day , but especially , in the end of the moneth , extraordinary rain and mist. this is so much the more to be observed , because in this countrey , seldom such extraordinary hail falls out . this year the agues and trembling fevers have been most frequent , and to many deadly . observation xviii . i did hear lately of a curious experiment in germany , made by a person of note , which i shall briefly in this observation , let the reader understand . and though i have heard since , that it is now published in print , yet i hope it will not be impertinent to mention it here , especially for their cause , who cannot conveniently come to the knowledge of such things . and for this reason also , that i may explicat the phenomena thereof , from the foregoing doctrine , and demonstrat particularly the true cause of that admirable effect , that 's seen in it , which i desiderat in the publisher . the auctor then takes two vessels of brass , each one of them in form of half a sphere , of a pretty large size . nothing can more fitly represent them for form and quantity , than two bee-skeps . only , each of them , hath a strong ring of brass upon the center without : and they are so contrived by the artist , that their orifices agree most exactly , so that when they are united , they represent an intire sphere almost . in one of the sides , there 's a hole , and a brass spigot in it , through which the whole air within , is exsucted , and drawn out , namely by the help of the air-pump . and , when by several exsuctions the vessels are made empty , the stop-cock is turned about , by which means , no air can come in . and , they remaining empty , are taken from the pump , and do cleave so fast together , that though a number of lusty fellows , on each side , do pull vigorously , by help of ropes fastned to the rings , yet are they not able to pull them asunder . and because this will not do it , he yokes in coach horses , six on every side , yet are they not sufficient , though they pull contrariwise to other , to make a separation . but to let the spectators see , that they may be pulled asunder , he yokes in or on every side , and then after much whipping , and sweating , they pull the one from the other . the cause of this admirable effect , is not the fear of vacuity , as some do fancy , for if that were , all the horses in germany would not pull them asunder , no not the strength of angels . it must then be some extrinsick weight and force , that keeps them together , which can be nothing else , but the weight of the invironing air. because , no sooner a force is applied , that 's more powerful , than the weight of the air , but assoon they come asunder . and so neither six men , nor six horses on each side are able to do it : but nine or ten on each side makes a separation . for understanding the true cause of this phenomenon , we must consider that the vessels are inches in diameter . if this be , then according to the last experiment , there are two pillars of air , each one of them as heavy as a pillar of mercury inches thick , and inches long , by which they are united . or , each pillar of air , is as heavy , as a pillar o● water foot high , and inches in diameter . for finding the weight of it in pounds , and consequently , the weight of each pillar of air , by which the two vessels are united , follow this method . first , multiply the semidiameter of the pillar , by the circumference , and this gives you , the half whereof is the bounds of the area , namely . and because foot contains inches , i multiply by , the product whereof is ; so many square inches are in a pillar of water foot high , and inches thick . now seing there are inches in a cubical foot , i divide the number , by this number , and i find square foot of water , and more . and because every square foot weighs pound trois , i multiply by the number , and the product is pound , which is the just weight of a pillar of water foot high , and inches in diameter , and which is the just weight also of each pillar of air , by which the two vessels are kept together , which will be more weight than seven hogs-heads full of water . this is easily known ; for seing a quart of our measure weighs seven pound , ( or to speak strictly six pound fourteen ounces , seing the standard-jug of striviling contains three pound seven ounces of water ) a gallon must weigh pound : but times , is . a puncheon then full of water , weighs pound . if then you divide by , you will find more than . the horses then upon this side have pound weight to draw , or stone , or the weight of seven hogs-heads full of water . the other horses upon the other side , have as much to pull . 't is no wonder then to see so much difficulty and pains to make a separation . it is observed , that before the air be exsucted and drawn out of the two vessels , one man is able to pull them asunder with his hands only . nay , which is more , if he but blow into them , as a man doth into a bladder , he will separat them . the reason is , because the air within , is of as great force , as the air without . 't is observable next , that the larger the vessels be in diameter , the more strength is required to pull the one from the other . upon supposition then , they were foot wide , i verily believe yoke of oxen , upon every side , would hardly disjoyn them ; because the weight of each pillar of air , would be no less , than pound , which would take strong horses to overcome the force of it . to pull the one vessel therefore from the other , there must be horses , that is , on every side . observation xix . though this observation may seem useless , because the proposals , that are mentioned in it , cannot be made out , and brought to pass , the author having died , before he had encouragment to prosecute them : yet for these following reasons , i have adventured to insert it here . first , that others , may either be minded to find out ( if possible ) his inventions , or set a work to find out somethings , that may be as useful . next , because , he was one of this same nation , and a great master of the mathematicks , not only in the speculative , but in the practical part chiefly , and admirable for invention . and for this cause principally i have presumed to mention his designs , and proposals , which were found among his notes , after his death , which are here insert , as they were written with his own hand , and offered to the publick , not only at home , but abroad to strangers . there have been men in all ages famous , for some one art and science beyond others , as apelles for painting , hippocrates for medicine , demosthenes for oratry , but who have been more famous in their time than some persons for their profound knowledge in astronomy , geometry , and the other parts of the mathematicks . what an admirable person was archimedes for his divine knowledge , both in the speculative , and practical part . yet , it was not his speculations simply , though excellent , that did so much commend him , as his inventions , and admirable engines for peace and war , as is clear from the romane histories , and others . i confess the students of these arts , are not so much in request now , at least amongst some , and that knowledge is not so much esteemed ; and the reason may be ; because some who profess themselves great masters , study nothing but the pure speculations , which sometimes are to small purpose , others before knowing the same , unless for perfecting of the mind , and giving to a man some private satisfaction . but such things will never commend a man so much as the practical part , and new invention will do . 't is surely a small business for one to do nothing , but to nibble at some petty demonstration . but when such speculations are joyned with invention and practice , for the profit , and use of men , among whom they live , then are they far more to be commended . and if this be not , such knowledge is of small advantage to themselves or others . many of the ancient , and late astronomers have been , and are famous for practice , as witness the indefatigable pains they have been at in making their observations . what hath so highly commended merchiston over all europe , as his inventions , especially his logarithmes ? and if all be true , that 's reported ( which i am apt to believe ) he might have been more renowned , for his many excellent engines , which though useful , yet because hurtful to mankind , he buried with himself . i am confident , if the author of these proposals had had time to have prosecuted them , he would have been celebrated in the catalogue of the most famous mathematicians of his time . but leaving this , i shall give you them in his own words : but first his apology . these bold proposals will need perhaps an apology to such , to whom the causes , and circumstances are unknown . let it suffice , that the proposer finding himself between two extreams , either to leave unprosecuted this affair , for fear of being mistaken by some , as impudent , or to commit himself openly to the charitable judgement of others , who will suspend their censure , till they have seen what his endeavours will produce . he hath rather chosen this last , especially considering , that his silence could not answer to his duty , which he owes to his countreys service , seing the following engines may be so useful to it . a deduction of the fabrick , causes , and occasions of these new engines , that set the inventer a-work , would take a long time to discourse upon . this paper therefore is only destined for a short informat●on of their use , the rest , which could not here be insert without impertinency , may be supplied afterwards ( if need be ) either by a discourse , or by a particular demonstration . the proposer then is of opinion , ( if self-love of his own inventions do not blind his judgement ) that these paradoxes may be truly affirmed . that if it shall please his majesty to arm with these new arms , and engines , foot , or fewer , this small number shall be masters of the fields in france , germany , spain , or where else it shall please his majesty , however encountered by the most powerful army of horse or foot , armed with ordinary arms , of pistol , carabine , pike , musquet , which europe can bring to the fields . the cause of this admirable effect , is in the quality of these new arms , by which , the whole horsemen and footmen of the enemy are rendred useless , and unservicable ; neither can they do any offence to these , who are so armed . the musquetteers , who can only serve against these machins , shall be put to such disadvantage , as it is impossible they can stand , the least time , in the common way of service with the musquet , it not being able to make one shot for twenty , which shall be made from these new engines . these new arms , have this advantage likewise , that these who are so armed , can by no force of horse or foot be broken , or put to disorder . the souldiers are also by them put to a necessity of keeping together , and fighting , and by them , they are so baricado'd , and strongly defended , that if they leave them not , they cannot be exposed to danger . this contributes much to good discipline , when the souldiers shall by necessity be tied to his duty , and fear , which otherwise makes him run away , shall here for his safety make him stand . these new arms are useful , as well in marching , as in combating , for with them , we may march securely two in front , through the straitest passages , and be able to force with them any advantage a strait passage can give to an enemy . besides , for a long hasty march , where victuals cannot be well carried , the souldiers are able with these arms to carry their own provision for eight dayes , with more facility , then they can now carry one dayes provision . to lodge in the open fields , these arms shall need no intrenching , for they sufficiently both arm and baricade the souldiers . and as they are useful in service , so are they a great deal cheaper than the ordinary arms. for although with thousand men so armed , the service of armed with common arms may be done , yet the whole price of them will not amount to that which will be required for arming corrassiers , as may be particularly deduced , from the particular prices of the arms , and engines fitted for the service of men . the proposer doth offer to shew , that these arms will not surmount pound sterling . the artillery will amount to , and the payments of this number of men so armed , yearly to pound . yet all these are taken in so large a latitude of reckoning , as the sum of arms , artillery , and payments , will not be much above pound sterling . the arms from which this effect is promised , are new engines , with which one man is able to do the service of a great many musquetteers . and those are of two sorts , either to be used upon a small wagon for footmen , or on a greater for a horse , with either of which , one hand is able to make the fire of musquetteers , and so much better , by how much it is more regularly , and fitly done for execution and offence . the new cannon shall have the like advantage above the old , both for easie carriage , being lighter , and for greater execution , shooting six , nine , or twelve bullets for one . these arms give not only this advantage at land in the field , but also in ships , and places of defence . these nine following propositions he likewise offered to make good , first , with one shot of cannon , to do the execution of five shot of the same cannon , in the common way of battery . secondly , to disable any ship or galley with one shot of cannon . thirdly , to fire any combustible matter with the shot of a cannon . fourthly , to make an machin or engine for transporting an army , which may be carried without the incommodity thereof . fifthly , to make a flotting fortress for defence of rivers , and prohibition of passages . sixthly , to make a mortar that hath a directory stell upon the carriage . seventhly , to make petards of divers forms , that shall be able to do twice as much execution , as those that contain as much powder . eighthly , to make small petards of great effect . lastly , to make bridges , and scaling ladders of easie carriage . observation xx. these observations being miscellany , require not a formal connexion between themselves , and therefore 't is no matter what method i keep in setting them down . and though this may seem not so pertinent , as others , yet because the design of it is only philosophical , and for advancing the historical part of learning in order to spirits , upon which the scientifical part doth so much depend , i have presumed to insert it here , considering also that there are some , who have adventured to deny their existence , and being ; which from such a history as this , may be more than probably evicted . i find likewise , that several writers have remarked such strange accidents , and have transmitted them to posterity , which may serve for good use . the subject-matter then of this observation , is a true and short account of a remarkable trial , wherewith the family of one gilbert compbel , by profession a weaver in the old paroch of glenluce in galloway , was exercised . though the matter be well known to several persons at that time , and since too ; yet there are others , eighteen years interveening , to whom ( perhaps ) such a relation will not be unacceptable , who have either not as yet heard of it , or at least , have not gotten the true information , which is here set down , as it was written , at the desire of a special friend , by gilbert campbel's own son , who knew exactly the matter , and all the circumstances , whose words are as follows . it happened in october , that after one alexander agnew , a bold and sturdy beggar , who afterwards was hanged at dumfreis for blasphemy , had threatned hurt to the family , because he had not gotten such an alms as he required : the said gilbert was oftentimes hindered in the exercise of his calling , all his working-instruments being some of them broken , some of them cutted , and yet could not know by what means this hurt was done ; which piece of trouble did continue , till about the middle of november , at which time the devil came with new and extraordinary assaults , by throwing of stones in at doors and windows , and down thorow the chimney-head , which were of great quantity , and thrown with great force , yet by gods good providence , there was not one person of the family hurt , or suffered dammage thereby . this piece of new and sore trouble , did necessitat mr. campbel to reveal that to the minister of the paroch , and to some other neighbours and friends , which hitherto he had endured secretly . yet notwithstanding of this , his trouble was enlarged ; for not long after , he found oftentimes his warp and threeds cut , as with a pair of sizzers , and the reed broken : and not only this , but their apparel cut after the same manner , even while they were wearing them , their coats , bonnets , hose , shooes , but could not discern how , or by what mean. only it pleased god to preserve their persons , that the least harm was not done . yet , in the night time , they wanted liberty to sleep , something coming , and pulling their bed-cloaths and linnings off them , and leaving their bodies naked . next , their chests , and trunks were opened , and all things in them strawed here and there . likewise , the parts of the working instruments , that had escaped , were carried away , and hid in holes and bores of the house , where hardly they could be found again . nay , what-ever piece of cloath , or houshold-stuff , was in any part of the house , it was carried away , and so cut and abused , that the good-man was necessitated with all haste and speed , to remove , and to transport the rest to a neighbours house , and he himself compelled to quite the exercise of his calling , whereby only he maintained his family . yet , he resolved to remain in the house for a season . during which time , some persons about , not very judicious , counselled him to send his children out of the family , here and there , to try whom the trouble did most follow , assuring him , that this trouble was not against all the family , but against some one person , or other in it , whom he too willingly obeyed . yet , for the space of four or five dayes after , there were no remarkable assaults , as before . the minister hearing thereof , shewed him the evil of such a course , and assured him , that if he repented not , and called back his children , he might not expect that his trouble would end in a right way . the children that were nigh by , being called home , no trouble followed , till one of his sons , called thomas , that was farrest off , came home . then did the devil begin afresh ; for upon the lords day following , in the afternoon , the house was set on fire , but by his providence , and the help of some people , going home from sermon , the fire was extinguished , and the house saved , not much loss being done . and the monday after , being spent in privat prayer and fasting , the house was again set on fire upon the tuesday about nine a clock in the morning , yet by providence , and the help of neighbours , it was saved , before any harm was done . mr. campbel , being thus wearied , and vexed , both in the day , and in the night time , went to the minister , desiring him , to let his son thomas abide with him for a time , who condescended , but withal assured him , that he would find himself deceived , and so it came to pass : for , notwithstanding that the child was without the family , yet were they , that remained in it , sore troubled both in the day time , and in the night season , so that they were forced to wake till mid-night , and sometimes all the night over . during which time , the persons within the family , suffered many losses , as the cutting of their cloaths , the throwing of peits , the pulling down of turff , and feal from the roof , and walls of the house , and the stealing of their apparel , and the pricking of their flesh and skin with pins . the presbytery having conveened at the place , for a solemn humiliation , perswaded gilbert campbel to call back his son thomas , notwithstanding of whatsoever hazard might follow . the boy returning home , affirmed that he heard a voice speak to him , forbidding him to enter within the house , or into any other place where his fathers calling was exercised . yet he entered , but was sore abused , till he was forced to return to the ministers house again . upon monday the of february , the rest of the family began to hear a voice speak to them , but could not well know from whence it came . yet , from evening till midnight , too much vain discourse was kept up with the devil , and many idle and impertinent questions proposed , without that due fear of god , that should have been upon their spirits , under so rare and extraordinary a trial . the minister hearing of this , went to the house upon the tuesday , being accompanied with some gentle-men , who after prayer was ended , heard a voice speaking out of the ground , from under a bed , in the proper countrey dialect , saying , would ye know the witches of glenluce ? i will tell you them ; and so related four or five persons names , that went under an evil report . the said gilbert informed the company , that one of them was dead long ago . the devil answered , and said , it is true , she is dead long ago , yet her spirit is living with us in the world . the minister replied , saying , ( though it was not convenient to speak to such a person ) . the lord rebuke thee satan , and put thee to silence ; we are not to receive any information from thee , whatsoever fame any persons go under . thou art but seeking to seduce this family : for satans kingdom is not divided against it self . after which all went to prayer again , which being ended ( for during the time of prayer no trouble was made ) the devil with many threatnings boasted and terrified the lad thomas , who had come back that day with the minister , that if he did not depart out of the house , he would set all on fire . the minister answered , and said , the lord will preserve the house , and the boy too , seing he is one of the family , and hath gods warrand to tarry in it . the devil answered , he shall not get liberty to stay : he was once put out already , and shall not abide here , though i should pursue him to the end of the world . the minister replied , the lord will stop thy malice against him . and then they all prayed again , which being ended , the devil said , give me a spade and a shovel , and depart from the house for seven dayes , and i shall make a grave , and ly down in it , and shall trouble you no more . the good-man answered , not so much as a straw shall be given thee , through gods assistance , even though that would do it . the minister also added , god shall remove thee in due time . the devil answered , i will not remove for you , i have my commission from christ to tarry , and vex this family . the minister answered , a permission thou hast indeed , but god will stop it in due time . the devil replied , i have ( mes. iohn ) a commission , that ( perhaps ) will last longer than your own . after which , the minister and the gentlemen arose , and went to the place where the voice seemed to come from , to try if they could find any thing . and after diligent search , nothing being found , the gentlemen began to say , we think this voice speaks out of the children , for some of them were in their beds . the devil answered , you lie , god shall judge you for your lying , and i and my father will come and fetch you to hell , with warlock-theeves ; and so the devil discharged the gentlemen to speak any , saying , let him speak that hath a commission ( meaning the minister ) for he is the servant of god. the gentlemen returning back with the minister , they sat down near to the place whence the voice seemed to come from , and he opening his mouth , spake to them , after this manner . the lord will rebuke this spirit , in his own time , and cast it out . the devil answering , said , it is written in the of mark , the disciples could not cast him out . the minister replied , what the disciples could not do , yet the lord having hightned the parents faith , for his own glory did cast him out , and so shall he thee . the devil replied , it is written in the of luke , and he departed , and left him for a season . the minister said , the lord in the dayes of his humiliation , not only got the victory over satan , in that assault in the wilderness , but when he came again , his success was no better , for it is written , joh. . behold the prince of this world cometh , and hath nothing in me ; and being now in glory , he will fulfill his promise , and god shall bruise satan under your feet shortly , rom. . the devil answered , it is written , mat. . there were ten virgins , five wise , and five foolish ; and the bridegroom came : the foolish virgins had no oyl in their lamps , and they went unto the wise to seek oyl ; and the wise said , go and buy for your selves : and while they went , the bridegroom came , and entered in , and the door was shut , and the foolish virgins were sent to hells fire . the minister answered , the lord knows the sincerity of his servants , and though there be sin and folly in us here , yet there is a fountain opened to the house of david for sin and for uncleanness , and when he hath washed us there , and pardoned all our sins , for his names sake , he will cast the unclean spirit out of the land . the devil answered and said , that place of scripture is written in the of zechariah , in that day i will cause the prophets , and the unclean spirit , pass out of the land ; but afterwards it is written , i will smite the shepherd , and the sheep shall be scattered . the minister answered and said , well are we , that our blessed shepherd was smitten , and thereby hath bruised thy head ; and albeit in the hour of his sufferings , his disciples forsook him , mat. . yet now having ascended on high , he sits in glory , and is preserving , gathering in , and turning his hand upon his little ones , and will save his poor ones in this family from thy malice . the minister returning back a little , and standing upon the floor , the devil said , i knew not these scriptures , till my father taught me them . i am an evil spirit , and satan is my father , and i am come to vex this house ; and presently there appeared a naked hand , and an arm , from the elbow down , beating upon the floor , till the house did shake again ; and also the devil uttered a most fearful and loud cry , saying , come up father , come up : i will send my father among you . see , there he is behind your backs . the minister said , i saw indeed an hand , and an arm , when the stroak was given , and heard . the devil said to him , saw you that ? it was not my hand , it was my fathers ; my hand is more black in the loof . would you see me ? put out the candle then , and i shall come butt the house among you like fire-balls . after which all went to prayer , during which time , it did no harm , neither at any other time when god was worshipped . when prayer was ended , the devil answered and said , mes john , if the good-mans sons prayers at the colledge of glasgow , did not prevail more with god , than yours , my father and i had wrought a mischief here ere now . to which one of the gentlemen replied , though a check had been given him before , well well , i see you confess there is a god , and that prayer prevails with him , and therefore we must pray to god , and will commit the event to him . to which the devil replied , yea sir , you speak of prayer , with your broad lipped hat ( for the gentleman had lately gotten a new hat in the fashion with broad lips ) i 'le bring a pair of shears from my father , that shall clip the lips of it a little . the night now being far spent , it was thought sit every one should withdraw to his own home . then did the devil cry out fearfully , let not the minister go home , i shall burn the house if he go ; and many other wayes did he threaten . and after the minister was gone forth , the good-man being instant with him to tarry , whereupon he returned , all the rest of the company going home . then said the devil to the minister , you have done my bidding . not thine , answered he , but in obedience to god , have i returned to bear this man company , whom thou dost afflict . then did the minister call upon the name of god , and when prayer was ended , he discharged mr. campbel , and all the persons of the family , from opening their mouth , in one word to the evil spirit , and when it spake , that they should only kneel down , and speak to god. the devil then roared mightily , and cryed out , what ? will ye not speak to me ? i shall burn the house , i shall strike the bairns , and do all manner of mischief . but after that time , no answer was made to it , and so for a long time no speech was heard . after this , the said gilbert suffered much loss , and had many sad nights , not two nights in one week free ; and thus it continued till april . from april to iuly , he had some respite , and ease . but after , he was molested with new assaults : and even their victuals were so abused , that the family was in hazard of starving ; and that which they did eat , gave them not the ordinary satisfaction they were wont to find . in this sore and sad affliction , mr. campbel resolved to make his address to the synod of presbyters , for advice and counsel what to do , which was appointed to conveen in october , namely whether to forsake the house and place , or not ? the synod by their committee , appointed to meet at glenluce in feb. , thought fit , that a solemn humiliation should be kept thorow all the bounds of the synod , and amongst other causes , to request god in behalf of that poor afflicted family , which being carefully done , the event was , through the prayers of his people , that his trouble grew less till april , and from april to august , he was altogether free . about which time , the devil began with new assaults , and taking the ready meat that was in the house , did sometimes hide it in holes by the door-posts , and at other times did hide it under the beds , and sometimes among the bed-cloaths , and under the linnings ; and at last , did carry it quite away , till nothing was left there , save bread and water to live by . after this , he exercised his malice and cruelty against all the persons of the family , in wearying them in the night time , with stirring and moving thorow the house , so that they had no rest for noise , which continued all the moneth of august after this manner . after which time , the devil grew yet worse , and began with terrible roarings , and terrifying voices , so that no person could sleep in the house , in the night time , and sometimes did vex them with casting of stones , striking them with staves on their beds in the night time : and upon the of september , about midnight , he cried out with a loud voice , i shall burn the house ; and about three or four nights after , he set one of the beds on fire ; which was soon extinguished , without any prejudice , except the bed it self : and so he continued to vex them . observation xxi . i need not make any apology for inserting this observation , even though it be well known upon the matter in this place . but because the thing is extraordinary , and that there are many who have not so much as heard of it , i have therefore presumed to mention it here . the matter is shortly this . there 's a certain woman , named mistris low , who had a real and true horn , growing upon the right side of her head , three inches above her right ear. the length of it is eleven inches , and two inches about . the form is crooked spirally . it is convex on the outer side , and somewhat guttered in the inner side . it is hard and solid , and all very near of the same greatness . it is not hollow within , as horns are ordinarily , but full , yet it seems to be spongious as a cane is . it was seven years in growing , and was cut off in may , by mr. temple , an expert chirurgeon here at edinburgh . observation xxii . this observation is for finding the primum vivens in animals . albeit i doubt not but the red spirit , or blood , in most terrestrial animals , is the first product of the primigenial juice , and therefore not improperly named the true callidum innatum of these creatures , by the noble and ingenious harvey , in his book de generatione . neither do i scruple to yeeld , that the heart , and appendent vessels , are the first formed , and perfected parts in the hotter kind of animals : yet i am confident to affirm , that in many of the colder , and moister kinds of aquaticks , if not in all , neither the redness and heat of the vital spirits , nor the formation of the heart , liver , &c. are previously requisite , to the structure and existence of the other parts ; seing the light of life , which at first inhabited the clear and cristalin radical moisture , before the formation of any particular part , doth alwayes move in every living creature , according to their particular exigency , without any absolute dependency upon any one part , or member ( excepting singular conditions , wherein they may be stated ) as to its substance , light , and motion : there being in some animals a simple undulation , in others a slow creeping , but in the more perfect , an impetuous running , or rather flying of the vital spirits , necessarily required for illumination and vivification of the whole . for confirmation , i shall give you this singular experiment . about the middle of march , the sperm of frogs ( according to the number of prolifick eggs therein contained ) sends forth a multitude of small round creatures , covered with a black , and moveable frock , which about the end of march , and beginning of april , by the gyrations of a tail behind , like a rudder , do slowly move their bodies in the water . at this time having opened severals of them , i found nothing ( apparent to the naked eye ) but a clear th●n membran , under the fore-named black frock , within which were contained a clear water , and some small fibres like intestines , and in the fore-part a small orifice like a mouth . about the middle of april , its motion is more vigorous , and the tripes within are most evident , lying in a very fine circular order , but as yet , there is no vestige of heart , blood , or liver , &c. about the middle of may , the feet formed like small threeds , appear thorow the black coat : within the breast , the heart is then visible , of a white and fibrous substance , the liver is white , and the gall therein easily discerned . but ( which is the head of this experiment ) the vital spirit , in form of a clear and pure water , is manifestly received by the nervous heart , and by the contraction thereof transmitted to all the body , thorow white transparent vessels , which being full of this liquor , do represent the lymphatick , rather than the sanguiferous veins . last of all do the pneumatick vesicles ( which in this amphibium supply the place of the lungs ) arise in the breast , after whose production , the lympid and crystalin liquor , while the heart is turgid therewith , seems to be red and fiery , but in the other vessels , it is of a faint pale colour , untill ( about , or near the end of iune ) the frock being cast off , and a perfect frog formed , the whole vessels are full of blood , or a red substance very thin , and clear : the liver , and pneumatick vesicles , &c. become red , and rosy ; so that the blood in this amphibium ( which in the more perfect animals is first compleat ) seems to be the last part in attaining its perfection . that salmonds , and great trouts have an aqueous liquor which runs thorow their arteries , and veins , before their blood attain the true consistency , and saturat tincture i am certain : whether it hold in many others , i suspect , but dar not affirm . hence it may be ( if mens observations , were frequent in all kind of anatomical inspections , in several embryo's of every species ) it would be found evident , that the blood in all these , called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 hath its immediat original from a simple homogeneous , and uniform liquor , and doth by gradual and frequent influences of the vital ferment of the heart , receive at length the full tincture , essence , and subsistence requisite for vivification , and illumination of the whole members . whether this experiment doth not sufficiently impugn the universality of the hearts first living , the original of the gall from the fervour , and ebullition of the blood , the production of the blood by the liver , and many other ancient errors , let any judge , who will but take pains to make and compare harveys trials de ovo , with this of the porwigl or gyrinus , ab ovo . yea , if the aqueous liquor , be not one with the vital spirit , and subsequent blood , then my eyes , and taste are altogether erroneous . moreover , it were to be wished , that physitians would not simply stand upon the galenick suppositions of the four alledged components of the blood , nor any such , or equivalent fancies of the latter chymists ; but that they would seriously examine the first original , and rise thereof from the primigenial juice , or liquamen , the progress , and perfection of its tinctures , how many renovations , or new tinctures it is capable of ; the vast difference between the blood of old and young animals , ( though , it may be , they are both univocal substances , while in their integrity within the vessels ) with the specifick discriminations , not only of that of any one aquatick , from any volatil , or terrestrial , but likewise of any one species living in the same element , with these that enjoy the same aliments , but of a different species . and lastly , the variety of particular constitutions , and singular properties of individual animals , radicated in the fountain of life , or first original of the blood. if these things , and many more , were truly inquired after ( though the cook be sometimes necessitated to throw away some of the broth with the scum ) i doubt not but the neoterick invention of transfusion of blood , would prove altogether ridiculous , and the ancient mistake of too much profusion of this treasure by phlebotomy , might suffer some reasonable checks from infallible experience , and sound reasons , not here to be mentioned . there are truths in natural philosophy , which ( i doubt not ) but sound reason and experience will convince the vain world of in due time . observation xxiii . this observation is concerning the aliment and growth of plants . the inquisitive wits of this , and the last age , having rejected the old opinion of the earths nourishing of plants , or being converted into their aliment , have made many laudable experiments for finding out the materials , and means of their growth , and vegetation , such as sir francis bacon's observe of germination , helmonts of a willow , and the noble mr. boyl's of a gourd , &c. for though a tree be cut down , and the root thereof wax old in the earth , and the stock die in the ground , yet through the sent of water , it will bud , as iob speaketh , chap. . , , . i shall add a short remark of a willow growing without earth . upon the of april , i set a top branch of the peach-leaf'd willow in a glass-viol , among ounces of pure spring water , with three small buds upon the top thereof , scarce yet discernable . the first ten or twelve dayes , little white specks appeared upon the sides of the willow , like small drops of quick-silver , or like the first bubbles that arise upon the fermentation of ale or wine , but no consumption of the water all this time . indeed the gemms , which stood three inches above the water , did visibly swell about the twelfth day . about the fifteenth day , i perceived small white roots within the water , upon several places of the plant , and observed the liquor grow somewhat thick , and decay in bulk considerably . having perceived this , i took another glass of the same bigness , with that wherein the willow grew , and having filled both top-full with spring water , i observed clearly the consumption of the water wherein the plant stood , to be so great , that during may , iune , and a great part of iuly , every week ( at least ) an ounce and an half , or two ounces of it were insensibly spent : whereas the other water , standing by in an open vessel of the same size , made not waste of one spoonful in a whole moneth . about the middle of august , the water turned very thick , and green , like that whereon duck-weed useth to grow , and the fair white roots were all obscured from the sight , although the vessel by the multitude of roots was not capable of the third part of water it received at first . at this time the branches were advanced to half the bigness , and a much greater length , than the whole stock , at its first planting ; and the leaves of as fresh a verdure , as any willow in the fields . thus , having observed , that a tree of four ounces weight , could in three moneths time , and little more , consume insensibly , seven or eight times its own weight of pure water , without the warm preservation of the earth , and by its own proper digestion , to thicken the remnant of the water , that it might serve for lorication of the tender fibres of the roots , i took the glass , the tree , and all , and threw them over a window , supposing it needless to recruit the water any more , and judging it impossible without the warm guard of the earth , that the naked tree could be preserved in winter : yet it had the good fortune to fall among some thick herbs in the corner of a little garden , where ( after it had lien all winter ) it was found , and brought back to me , the branches fairly budding in april , the whole tree fresh and green , yet very little water was left in the glass , by reason , as i judged , it had fallen upon its side . then i endeavoured to keep water about it , but the stock filling the neck of the viol , and the roots the whole body thereof , the starved plant died in may , after it had lived a whole year without earth . from this it would seem , that this kind of tree , ( and it may be , many moe ) doth dissipat insensibly six times more liquor , than it doth assimilat , and by consequence , that a great quantity of moisture is necessary for maintainance of great woods . neither is there any way so advantagious for draining moist ground , where there are no living springs , as that of planting abundance of timber , which will best agree with that kind of soyl : for by this means , what was formerly noisome , and superfluous , is now converted partly into the useful aliment of the timber , and partly sent abroad in insensible exhalations , which ( according to the nature of the emitting plants ) prove either very noisome , or wholsome to the neighbour-inhabitants . great care therefore would be had in the choise of such trees , as are to be planted in such moist ground , as are near to mens dwellings , or places of concurse . they are not fools , who prefer firs , and lime-trees in their avenues to oak and elme . let the effects of the atomical exhalations of alder and oak upon fine linnen , and white skins be more particularly noticed . having spoken somewhat of the aliment and growth of plants , i shall in the next place give a short hint at the motion of their aliment , especially of trees . that the alimentary juice of plants , is much thinner , than that of animals , no man , i suppose , will deny , seing that is conveyed thorow the trunck , or body of the plants , by inperceptible pores ; but this ( for the most part ) is sent thorow all the members , through patent and manifest vessels . but how the nourishing , and vital juice in plants doth move , and by what passages , hath not yet been made known , by any that i have seen . i made once a few observations , for trying of the motion of the aliment of trees , which bred in me this conjecture . the nutritive juice of trees is transmitted both to the roots and branches , through the heart , or pitch , and woody pores of the timber , and when it is come to the extream parts , it returns again from the tops of the roots and branches , between the bark and timber , into these forenamed interior passages , and so back to the extremities again , and that continually , so long as the life remains . and because the substance of that skin , or bark , which invests the fibres of the root , is more open and porous , than that which is upon the outward branches : therefore it seems , that so much as is superadded to the stock of the former aliment , from the earth , is conveyed to the heart and pitch , by means of , and together with , that part of the retrograd juice , which returns from nourishing , and enlivening the timber of the root-branches , ( for it is an easie experiment , to make the top of any tree become root , by laying it down ) and receives the impressions of the life of the tree , common to the whole mass of alimentary juice , like the i hyll in animals mixed with the blood of the veni-cave , before it come to the heart . this motion is not to be thought alwayes alike swift , or of equal celerity : for the vital juice of the tree becomes so thick and oleagenous in the winter , that the motion thereof to the outward , is scarce discernable ( though the preparation of the gemmes , both for leaves and flowers , are observed by the curious , and can be distinguished , even in the coldest seasons ) and the returns inward are in so small quantities , that they are rather like vapours , than liquid juice . indeed , some trees , when their root-branches are cut ( even in winter ) will yeeld no small quantity of an acid liquor , which by addition of the recent leffas from the earth , smells evidently of the matrix , from which it did proceed . moreover , the passages especially from the branches to the trunk , are so straitned and contracted , that the bark cleaveth to the timber , as every wood-man knows . but so soon as the warm spring hath attenuated the ever-flowing juice in the whole tree , then doth it become turgid , and more aqueous over all : the passages , and channels both in the trunk , and among the tunicles , and particular skinnes , are so palpably filled with this vital juice , that having no sufficient place to be comprehended in , it putteth forth new growths both in the top , and in the root , which may be easily seen to have more pitch than wood , and to be sealed on the extremity , with the vestiges of a future gemm ; that by the former , they may the more freely receive the vital influences from within , and by the latter , may be secured from the depredation of the external air. to prove the motion ad extra , or to the extremities of the branches ; take the branch of any ordinary tree , about the bigness of a mans wrist ; make it bare near the body of the tree of all bark , and subjacent tunicles ( for every tree according to its kind , hath moe or fewer skins , which serve for veins , within the strong outmost cortex ) at least for the breadth of a span , or two hand-breadth . then tye up the place , so excorticated with a compost , made of horse-dung mixed with earth ; let it stand so from may , till november . then cut off the branch , a little above the compost , near the body of the tree , and you shall find it living and fresh , like the rest of the branches : yea , small roots shall evidently appear to have come forth under the compost near the bark , but not under the bared place . this branch in many kind of trees being planted , will hold , though not in all . i say then , seing the foresaid bough is nourished from may till november , it is necessary , that it receive nutriment from the body of the tree , by the internal porosities thereof : for the bark being discontinued by excortication , can send nothing upward towards the top of the bough ; and if it received nothing from the root , it would wither in a few dayes . yea , leave the discovered part naked , but for a few dayes , and of necessity the branch dieth , the aliment thereof being exhausted by the air , before it can reach the extremities of the bough . that the vital balsome of the tree returns from the extremities by the internal bark , and inward superfice of the external , together with the smooth outward part of the trunck , although the necessity of both timber and bark in all incisions , and inoculations , might perswade the judicious , and the visible course of the juice of the sycamor in february , and of the birch in march , upon the cutting of any small branch , might convince any curious beholder ; yet the knot or callus , that is made upon grafted trees , will better inform the ignorant : for this knot being alwayes upon the shoulder , or root of the graff , and never upon the top of the stock , doth evince clearly , that it is made by restagnation , of the descending , and not of the ascending juice : otherwise , why doth it not swell the top of the stock , as well as the root of the graff ? or why doth it not extuberat in any other place of the graff ? these are accidental varices , which can hardly be shunned in imping , seing the top of the stock ( except when it is very young and succulent ) doth not receive so kindly , as it ought , the retrograd sap , although all that is sent out to the graff must ascend thorow the pores of the stock . hence many times a considerable part of the stock is mortified , because although abundance of aliment ascends to the head or top thereof , yet no more of it goes to the branches , but what is bestowed upon the graff , a great part of the rest being exhaled by the air ( especially in big stocks ) and consequently , the place defrauded of its nourishment : no other wayes than when the motion of the vital sap faileth , either in the whole , or in part , a total decay or particular mortification of some part necessarily follows , as in the stemms of annual plants , and mortified tops of the ectrapelous branches ( that i may so call them ) of willows , plumbs , &c. we may observe every autumn . observation xxiv . sir , i was not a little surprised , at the receit of yours , when i had considered your desire in it , being prest with two difficulties , which seemed equally hard to evite . the one , to give you my judgement in a matter wherein i have been so little conversant my self , and have had the steps of no other to follow , never one having hitherto touched that subject in writting ; i mean of coals , and other minerals of that nature , their course , and other things relating thereunto ; the observation whereof ( i grant ) wants not its own pleasure , and usefulness . the other , to refuse the desire of a friend , when importuned , to whom i owe my self , by many obligations . this last having prevailed , hath determined me to assay the overcoming of the first . and though i am confident , what account i can give you , shall give but very little satisfaction : yet i adventure to offer it , such as it is , very freely in the following discourse , wherein you are not to expect , that i will meddle with some questions , thereanent , which might be more curious , and pleasant , then profitable , or satisfying , such as , if coal , and free-stone , which keep one course , and have the same accidental qualities , have been created in the beginning , in their perfection , as wee now find them , and since that time only preserved , as they were created for the use of men , to whom all sublunary things were made subservient ? or , if they have been but produced gradually , as they speak of gold , and other minerals , by the influence of the sun , in the bowels of the earth ? and if their production be of that nature , out of what matter they are formed ? these things being above my reach , i shall leave their inquiry , to those that are knowing in the secrets of nature , and shall therefore give you a narration , of what either i have observed of these things , which occurr in the winning of coal in my own experience , or by conversing with others of more experience than my self , in doing whereof , i shall follow this method . first , i shall speak of these things that are common to all coal , wherein they all agree , and which are , as it were , essential to all , and of there differences , which are but accidental , and gradual sometimes , and yet are abundantly conspicuous , and causeth different effects in the working ; as their dipps and rise , and streek , for so are they termed . secondly , of some things , which are but accidental to coal , and yet so ordinary , that scarcely any is found without them , in lesser or greater degrees ; such are gae's , and dykes , that alter the natural course of the metalls , very incident to every coal , though in some less frequent , conform to the nature and kind of the ground , where the coal is . thirdly , i shall speak something of damps , and of their different causes , and effects : of wild-fire , and other such like things , which are met with in the working of coal . and lastly , of the best way for trying grounds to find coal , where never any hath been hitherto discovered : of carrying on of levels , for draining the water of coal and making it workable . it is to be cosidered , that all free-stone , though of different natures , hath the same course , with the coal , that ly either above them , or below them , except it be accidentally , interrupted : therefore , whatsoever is spoken of the one , is applicable to the other . and so we find in digging or sinking , that after the clay is past , which keeps no course , all metals , as stone , and tilles ( which are seems of black stone , and participat much of the nature of coal ) ly one above another , and keep a regular course ; wherein the three things most remarkable are their dipp , and rise , and their streek , as it is termed . the dipp , and rise , are nothing but a declining of the whole body of the metalls . and this general holds , that all of them from their center rises , till they be at the very surface of the earth ; some only at a foot or two foot , some at an ells distance from the surface , which is here termed a cropping : and whether coal or stone , the nearer they come to the surface , the softer they become , till at last they are converted , if it be a stone , to a very sand , and if coal , to a dross , which will not burn . this declining or dipping , of the coal , is sometimes greater , and sensible , sometimes lesser , and almost insensible . there being some , that if you consider the declination , it will not be found one foot in ten ; some one foot in twenty , or one in thirty . whereas in others it will be one foot in three , or one in five . and sometimes it hath its course from the center of the earth , almost in a perpendicular to the surface , it cutting it , near to a right angle . the first sort , they term flate-broad-coal , in regard of the plainness , and evenness of its course . the next , they call hinging-coal . the last is called edge-coal . the first is the most profitable , in regard , that it 's long before the coal-hewers can reach the cropp , and consequently the more of it is workable . the second and third sort , are sometimes of their own nature , more firm , and fitter for burning , but less of them can be reached in working . the course of all the three is most perceptible in the three following schematisms . figure . in all the three figures , the point b is the cropp of the coal . the line bc is the body of the coal declining or the dipp from the cropp . ac is the perpendicular , falling from the horizontal line , whereby the true declination or dipp of the coal is found . so that after you have found your coal at b , you must set down your sink at the point a. in the flat-broad-coal , which we suppose only to decline , three fathoms in sixty ; the sink , that answers to the perpendicular ac , will be of deepness three fathoms . if the distance ba , be supposed to be fathoms alongst the grass , or surface , then will the deepness of the sink be six fathom , and so forth . in the second , if the coal be supposed to decline one fathom in three , the sink ac , being set down at the same distance from the cropp b , with the former , it will prove thirty fathom deep . if the said distance be doubled , it becomes sixty fathom deep , and so forth . in the third , keeping that same distance alongst the surface , you shall not encounter the coal with a perpendicular sink , because of its great declination , and therefore through want of air , and other difficulties , you cannot dig so deep , as is necessary to that effect , except the sink should be made to decline , as doth the line ad. all these dipps are to be seen in several places of lothian . the first is most conspicuous in the earl of wintons ground at tranent , where the coal , and other metals are extraordinary flat and even . the second is within the said lordship of tranent , in a piece of ground , called wester-fauside . the third in lonhead of laswaid , which pertains to sir iohn nicolson of nicolson : and in many other places , one may see very different declinations , who is curious to observe them . from this general position of the dipp , and cropp of all free metals , there is one consequent , which is no uncouth observation , namely that these metals rising from their dipp to a cropp , every one of them riseth in their proper course , if none of these things whereof we shall treat hereafter interveen , and make an alteration , that is the coal or stone , which is lowest , comes farrest out in its cropp●ng , which is easily understood by the subsequent schematism . figure . wherein the line am represents the surface of the earth . cd . ef. gh . ik . lm , are so many several metals , lying in course one above another . suppose cd were a stone , and the roof of the coal ef ( for so they term the stone , immediatly next above the coal ) and gh , ik , were other two stones , interveening between the coals ef , and lm , then if the cropp of the uppermost coal be found at f , the crop of the stone above it , must be found back , at the point d , and the cropp of the coal under it , which is lm , must be found at m. and this distance of cropp is proportioned by the length of the perpendicular between them , and the quantity of their declination . for , the more even and flat a coal is in its course , and other metals , above and below , the farder doth the cropp of the lowest coal advance before the cropp of the uppermost . for illustration whereof , let us suppose in two several grounds , two coals , between which , there is an equal distance of perpendicular . and suppose the metals in the one ground to decline at to , the other at to , then will the distance between the cropps in the two grounds be very considerable , as may be represented by the two following figures . figure . . suppose then , that di , is of equal length in both triangles , which is the perpendicular , between the two coals : yet df in the fifth figure , is much longer than df in the . and the reason is evident , because the angle dif , in the , is greater then the angle dif in the : and therefore the base df , which is subtended by the greater angle in the , must be greater then the base df , which is subtended by the lesser angle in the , which euclide proves in his . proposition of his first book , and is demonstrat by proclus in the scholium to the th proposition of the same book . by this is made to appear the profitableness of a flat-coal , beyond a hinging-coal , which was touched before , in regard that having the sinks of equal deepness in both , there is much more of the flater-coal to be wrought , before it cropp out , then of the hinging , as there is a difference between the lines df in the first and second figure , or between the lines if , in the same . if it be enquired , if in rising grounds , where there is a considerable ascent above ground , the coal keeps a proportion in its rising and dipping with the ascent and descent of the ground above ? i answer , there is no certain and constant proportion kept , whatever sometimes may happen . for i have observed some coals upon grounds of a considerable ascent , and their dipp run quite contrary to the descent of the hill : and others have had a quite contrary course to that , and have declined , or dipped with the declination of the ground above ▪ but in the streek ( whereof i shall speak a little hereafter ) there is more proportion ordinarily to be remarked . there remains only one question about the dipps , and risings of coals , which i shall a little consider , having encountered different judgements anent it , in conversing with persons , who had experience in coal , viz. whether coal and other metals , after they have declined such a length from their cropp , suppose from west to east , take another course , and rise to the same point , to which formerly they dipped ? figure . as if the coal dipped from a , which is the cropp , to b , which should be the center of that body ; and after that rise to c ? or if it should continue its declination thorow b to d , which is antipodes to us ? i shall not offer to determine in a matter wherein there can be so little certainty attained , but shall give my opinion , which is founded upon the experience i have had , and observations i have had occasion to make on that head. and first , i find in all these coals , wherein no contrary cropp or rising could be visible , there are invincible obstructions ; as either , they have been near the sea , and have dipped that way ; and so if they took any contrary course , the cropping behoved to be in the deeps , and so no access to trace them . or next , they have dipped towards the foot of a mountain , and so the ground above rising the same way which they declined ; their course could not be pursued , till a contrary rising should be discerned . or thirdly , they have encountered some gae , or dyke , which hath cut them off , before they came to their full dipp , and thus their course was obstructed . now , those that have been acquainted with no other coals but such , i think it not strange , if it be hard to perswade them of those things they have not seen . but besides all those kinds , i have seen others , whose contrary rising and dipping have either been visible to the eye , or demonstrable by reason . for example , i have entered under ground , as it were at the point c , at the very grass-cropp , and have gone following the dipp of that coal to the point b , at which the course hath altered , and carried me out at the grass at a , which are two contrary points of the compass . and that alteration of course was not occasioned by any gae , or trouble , which sometimes have that effect , the ground being very clean , and good metals , keeping their course most regularly . there are other instances for confirming my experience , in fields , which are so large , that 't is impossible to work the coal so far to the dipp , it falling deep , and so wants level for conveying water from it , or wants air , for following it to such a deepness , as to overtake its center , where it takes a contrary course , and yet the contrary cropp hath been wrought in several places , which is evident to be a part of the same body , with the other , both by the nature of the coal it self , by the metals lying above it , and the coals below it , all which keeping the same course , except when they encounter troubles , which are incident to some parcels of ground , more than to others . the greatest field i know wherein this is conspicuous , is in mid-lothian where is to be found , the cropping of a coal of a considerable thickness , which is termed their great-seam , or main-coal , and the other coals lying below it , which may be traced in the order following . at preston-grange these coals are found dipping to the n w , and rising to the se , which have been wrought up to wallifoo●d : from that along by the foot of fauside hill , the dipp lying in the lands of inneresk , which marches therewith on the north. from thence it runs through the ground of carberry , every one of these grounds from preston-grange , giving levell to another . from thence , through a part of the lands of smeaton , and next through a piece of ground belonging to the family of buccleugh , called condon : and through west-houses , which belongs to the earl of lothian , and at cockpen , and stobhill , from thence runs through to carington-mill ; all which is a course , which in streek lyes near to sw , and nw , and will be in length about eight miles . from thence , the course of the coal turns , and is found in the barony of carington , white-hill ramsay , gilmerton , and from thence taking its dipp , quite contrary to what it had before , the other dipping n and nw , or ne , according to the turn of the streek , it dipps there s , se , &c. and from gilmerton , it is found at burntstone , a piece of ground belonging to the earl of lauderdale : and from thence at the magdalen pans , where the turn of the cropp being within the sea , is not seen , till it be found at preston-grange , where we began to remark its course . the parcel of ground , under which this great body of coal lyes , is of a considerable extent , it being eight miles in length , and five or six in breadth ; in regard whereof many other coals are found lying above the great coal , the cropps whereof doth not come near the cropp of it , by a considerable distance . though this instance alone , may sufficiently convince , yet i shall not be unwilling to give another . the parcel of ground , in which this coal is found , is not of so great an extent , as the other , and therefore its course may be the more easily traced . for the greatest part , it belongs to the earl of winton , and lyes within the lordship of tranent , whose contrary cropps , are most conspicuous . this great coal , which is , or foot thick ( beginning at the head of the toun of tranent ) where it hath been wrought , runs sw towards the march of the lands of elphingston , belonging to the lord register , and continues in that same course , till it come near to the house , and for the most part dipping to the se. and near the house , the cropp is turned downward towards the march between elphingston and ormiston , where the dipp is contrary to the former . and from elphingston-mains , it takes its course almost round , through the lands of panston , and returns to the toun of tranent where it began , which body of coal will be in length two miles , and in some places , as much in breadth . now , i leave it to the judgement of any person , if there be not more reason to perswade , that this should be the natural course of these minerals , where such pregnable instances , to evince it , are found ; then to conclude the contrary from these coals , the course whereof cannot be followed , because of the invincible impediments , i mentioned before . however , i leave every one to be determined , by his own opinion , and shall be satisfied to injoy my own , till these of more experience convince me of the contrary . there are some other things farder to be remarked about the dipp , and rise of coals , which ( possibly ) every one hath not seen , they being so very rare , and therefore are not fit here to be passed without being considered . one is , of a coal , which having that contrary dipp and rise , ( whereof i have been speaking ) in one of the cropps , hath not come out to the grass , and terminat ; but after it hath risen a considerable way in its contrary course , in stead of cropping out , hath taken a dipp towards the same point , to which it dipped first , and so having dipped to the center of its course , it hath risen again , and cropped to the contrary point , as is to be seen in this eight figure . figure . where ab is the surface of the earth . the point b is the cropp of a coal dipping from nw , to the se. from c it takes its rise , and course to a contrary cropp , towards the point f , where the dead cropp ought to be found . but in stead of going that length , it takes another course from the point e , dipping se towards d , from which it takes its rise , and continues it to the point a , where it terminats , and where the dead cropp is found . i grant , that it meets with a trouble , or gae , at the point e , which seems to be the cause , why its natural course is changed . but it s very extraordinary to see such an effect . but of this afterwards , in its own place . there is yet another thing to be remarked , in the dipps , and risings of coals , which is this . in the most part of coals , that have their course from dipp to cropp , without the intervention of a dyke or gae , the declination is straight down , from the horizontal line drawn from the point of the cropp , to the fardest point of the dipp . that is , the coal declining from that point in a right line , makes with the horizontal line , a right lined angle , angulus rectilineus , though in some the angle is more acute , and in others less , as is to be seen in the first , and second figures , where ab being the horizontal line , and b the cropp , bc is the body of the coal declining , which meeting with ab in the point b , constitutes a right lined angle , and where abc in the second figure , is a greater angle , then abc in the first . yet i have seen a coal , the body whereof from the dipp , or fardest point of declination , had its rise towards the cropp very insensibly , it being flatt , and then began to be more sensible , till at last coming near to the surface of the earth , it takes in a sudden such a rise , that from declining one foot of or , it declines now one foot of three , as may be made evident from this following figure . figure . where ab is the line drawn from the extream points of the cropp , right horizontal . the body of the coal rising insensibly , is dc . but assoon as it comes to c , it riseth with a great ascent till it cropp out at a. here you see , that in stead of one side of a triangle , which the course of other coals in their rising , or in their declination makes ; this coal in rising makes two sides , namely dc , and ca , the figure dbca being quadrilateral . the coal of this course was really wrought , and is yet visible in its waste , where there is found no gae or dyke to make this alteration . these are the chief things that i have thought worthy of observation in the dipps , and risings of coals , and therefore i come now to touch a little the other part of their course , which is commonly termed the streek of a coal . to make intelligible to those , who are not experimentally , acquainted with coal , this term , or what the streek is , we must lay this foundation , that the coal is a physical body , and so hath its three principal dimensions , which do constitute it so , viz , longitude , latitude , and profundity . it s latitude , is that part contained between its extream lines , which is measurable by its surface , to which its dipping and rising , though alwayes incident , yet is but accidental . it s profundity is to be measured by the distance , between the two surfaces , immediatly next to it , above and below : which are termed in coallery its roof and pavement , because of the resemblance they have to the roof , and pavement of a house . the longitude is nothing else but what is termed by the coal-hewers , the streek . for if you imagine a line drawn along the extream points of the rise , or cropp of the coal , that is properly the streek of the coal . there are but few things to be remarked , as to this part of coal : only first to find how it lyes , to what points of the compass it moves . for knowing whereof , there is this general rule , that , having found your dipp and rise , to what ever points that course is directed , the streek is to the quite contrary . for supposing a coal dipp se , the two points , that respect the dipp and rise , must be se , and nw , being the points opposite one to another . then it must needs follow , that the streek must run sw , and ne , which two courses divides the compass , at right angles . and therefore , where a coal is found to have contrary dipps , and risings , they declining sometimes to all the points of the compass ( whereof there hath been given two notable instances before ) it must needs follow , that there be also contrary streeks , and so the streek of a body of coal is sometimes found to describe a round figure , though not perfectly circular , and somtimes a multangular figure . for it cannot be supposed that the streek makes alwayes a right line , between the two points , from which it is reckoned . for example , between the laird of preston-grange his house at preston-pans , and the stob-hill , there are the streeks of several coals , lying one above another , which will be of length , about seven or eight miles , lying near upon sw , and ne ; yet the cropps of the said coals ( their dipp , and rise , being nw , and se ) are sometimes farder advanced towards the se , sometimes farder back towards the nw , by the difference of a mile , and this generally occasioned by the encounter of a dyke or gae , whereof hereafter . the same question , that occured in the coals dipping towards a hill , on rising above ground , comes to be inquired into here ; viz. if a coal encountering amascent , or brae above ground in its streek , rises also with the ground , and keeps its ascent ? i answer , i have found it so in all the coals i have ever seen of that nature . god in his providence , having so ordered it , that thereby it may be the more useful , in regard more thereof may be wrought by one level or aquaeduct , by which the water is conveyed away , as afterwards will be observed in speaking to levels . for confirmation whereof , i shall bring instances both of coals , that declines towards the hill , and of others that declines with the same dipp , the hill hath it self . in the coals of bonhard , grange , kinglassy , and kinneil , which keep all one general course ; the ascent above ground is from the sea , ( which lyes north ) towards the south , or thereabout ; the coal dipps or declines towards the nw , and so consequently rises to the se. the streek of these coals , is from the ne to sw , which slops alongs the hill , and comes up to the top thereof to the westward of the house of bonhard . now , in sinking in that ground , if an equal proportion be kept , in all the sinks from the cropp , and a just allowance given for the different rising above ground , the sinks will be near of an equal deepness along all the streek . so that a sink upon the same coal near to the sea , which is the ne point of the streek , at equal distance from the cropp , will be as deep as a sink upon the top of the hill , being the sw point of the streek at the same distance from the cropp , allowing alwayes the different rise above ground , and excepting some particular troubles falling in upon the metals of one sink , and not of another , and so making them dipp more , which will occasion a difference of the deepness . the same is also found in the coals of dysart , and weems . as also in that great body of coal before mentioned , between preston-grange and stobhill , the declination whereof is to the ne , which is also the course of the descent above ground . another instance is from the coals within the lordship of tranent , the dipp whereof is of another course , being contrary to the descent of the hill , viz. the coal dipping to the se , and consequently the streek running sw , and ne , where the same is to be observed that was seen in the other , anent the equality of the deepness of sinks along the streek , with the same allowances , and exceptions before mentioned . some have been of opinion that streeks of coals ly generally south and north , or to some of the points near to these two cardinal ones , between south and sw , and north and ne , as south and by west , and north and by east , &c. to which general i cannot agree , in regard of wh●● i have before made evidently appear , viz. that some coals have their croppings towards all the points of the compass , and the streeks being regulated by the cropps , they must necessarily be judged to have their courses proportioned to theirs : so that if a coal dipp to the true north , and rise to the south , the streek must be east , and west . however , i acknowledge two things , for confirming that opinion . first , that of all the coals i ever have seen , where these contrary dipps and risings , could not be traced , and made visible , the streek hath inclined to those points of south and north. but i must also confess , that they are but few i have seen , in respect of what i have not seen , and so if any others experience , who have seen more , contradict mine , i shall willingly yeeld , and not be tenacious . next , in these coals , which i instanced , that have their cropp to all the points , and consequently their streeks , and in others of the same nature , which i have seen , and not instanced , i found that part of the streek , which lyes towards these cardinal points , to be the greatest , being double , or triple to the other sreeks in length . so that when the streek , that lyes either along the one cropp , or the other , towards the sw , and ne , will be seven miles in length , that lying se , and nw , will be but four , and sometimes less . and this is all the account i can give , of that part of coal , called the streek . the second thing i promised to speak of , was of some things , which are but accidental to coals , and yet so ordinary , that hardly are any found without them in lesser , or greater degree , such are gae's , and dykes , which alters their natural course , and they being the occasion of so much trouble , in the working of coal , and following its course , the coal-hewers call them ordinarily by that name trouble . this trouble or gae then , is a body of metal falling in upon the course of the coal , or free-stone , obstructing , or altering their kindly and natural course , keeping no regular course it self , and being of nature alwayes different from the metal , whose course it interrupts . and these gae's differ also among themselves , in their nature , and in their course they keep : or more properly in the way wherein they encounter other metalls , and in their effects . in their nature , for some of them consists of an impregnable whin-rock , or flinty-stone , thorow which it is almost impossible to work : and if there be a necessity to cut them thorow , it is done at a vast expence , and takes a long time , and must be cut open to the surface of the earth , it being impossible to mine it under ground . some of them are again of stone , like a free-stone , but seems rather an abortive of nature , they having no rule in their course , by which a man can follow them , nor can their stone be useful . in their encountering of coals , or free-stone , sometimes they encounter them in the dip , and sometimes in the streek , and sometimes between the two . these that are met with in following the dipp of the coal , ly along the streek thereof . for example , if the coal dipp se , the gae lies ne , and sw . these that are encountered in the streek , lyes to the dipp and rise : so the coal streeking ne , and sw , the gae is found to ly se , and nw . others of them , lyes between streek and dipp , that is to some point between the two : as the streek being sw , and ne , and the dipp and rise se , and nw , there may be a gae found lying wsw , and ene . now , when i speak of a gae's lying to such points of the compass , this doth not contradict what was said before , that they had no regular course themselves . my meaning being , that though they have a certain length , lying between two points , and a thickness between two metalls , yet by the metal of the gae it self , it is impossible to know its course , as it is in other metalls of coal or free-stone , whose courses are discernable at the first view . their effects are different , as their nature and course are different : only they agree in these two generals . first , that all of them renders that part of the coal , that comes nearest to them , unprofitable and useless , though some less , and some more , they being unfit for burning . and it is remarked , that these gaes that consists of whin-rock , renders the coal next to it , as if it were already burnt , being so dried , that it moulders in handling it . in others , the coal is not altogether so ill , and yet its nature is altered , from what it is at a distance from the gae . the next general is , that all of them alters the natural course of the coal in less or more , some of them making it dipp much more then its ordinary course , which they call down-gaes : some again making their rise much more than their course , which they call up-gaes . others making an alteration as to the streek , causing it go out beyond its ordinary bounds , as we observed before in that great streek of coal between preston-grange and stobhill . now it is to be considered , that when in working of a coal , whether to the dipp , or rise , or streek , one of these gaes is encountered with , the coal is quite cut off , and as it were terminat : so that you see nothing where the coal should be , but either a stone , or clay , or rotten till , or some such thing . and the practique of coallery is to trace the course of the coal through that , till you overtake it in the other side . and before any thing be said to that part , you must notice , that some gaes are of greater force than others , and their influence upon the course of other metalls greater , whence you shall see a threefold effect . one is , that by some great gaes , which a coal meets with , it is quite cut off , so that in the other side thereof , there is not a vestige of that coal , or of any other metal that was above it , or below it , to be seen . and if there be any other coal , as sometimes there are , they are quite different from them of the other side . i said by some , because there is one instance to the contrary , which is somewhat singular . in the earl of winton's ground at cockeny , there is found a course of coals and free-stone , dipping to the se in the links ; and upon the full-sea-mark , there is a tract or course of whin●rocks lying e and w , underneath which these coals and stones comes thorow without alteration of course , and are found within the sea-mark , with the same dipp and rise upon the north side , they had upon the south side of the said rocks : and yet the coal is encountered upon the south hand by a gae under ground , through which it passeth , not without a considerable alteration . the greatest of these gaes , that i know , is that which takes its beginning , that we see on land , at the harbour of the pans , called achisons-haven , which hath been cut by preston-grange , for level to his coal , and goes from that to seton , which may be traced above ground , almost the whole way ; and hath been cut at seton●a ▪ for serving the level of that coal now wrought at tr●nent . from thence it passeth through the fields of long-niddry , a place pertaining to the earl of winton , and through the coats , which pertains to the earl of hadington , till it joyn with pancreck-hills , a tract of rocky-mountains , from whence it is traceable to linton-bridges , where it is v●sible in the water , the water of tyn falling over it , and making a lin , which they call linton-lin ; from thence to the east-sea . and it is known by sea-men , that it keeps a course thorow the firth from achisons-haven , ( whence we reckoned its beginning upon land ) towards the west and nw , it being found to the southward of inch-keith , and before leith , where stands a beacon , and so can be traced to the north shore . the second effect of gaes , is to cut off the coal quite , as to a part of the field , so that in the other side , having pierced the gae , you shall not find the coal , and possibly not within a quarter of a mile of the gae , which cuts it off , and at that place shall only find the cropp and the body dipping , as it did before it was cut off ; and if you shall measure between that side of the gae , where you lost your coal ( i suppose the coal then being fathom from the grass ) to the place where the coal in the other side of the gae shall be found at the same deepness , it will be near paces . for making this more intelligible , let us suppose a coal dipping se , and in working to the dipp , there is a gae encountered with ( this was really done in a piece of ground i know , and so it is no meer supposition ) at which gae the coal is cut off ; for finding whereof the gae is pierced , and nothing found in the other side , viz. in the se side of the gae , but at more than paces distant , the crop of a coal , which lyes under the coal , that was lost , was found , after which it was easie to find the other . now , that it was the same coal , that was lost , upon the north side of the gae , is not only evident , by the kind of coal , and all the metals above , and below keeping the same course , but by this , that the gae wearing out towards the west , the two parts of the coal that was separated by it , joynes themselves again , and continues in one body , as they were before separation . the last effect of the gae is , that it doth not quite cut off the coal from the other side of it , but makes an alteration in the course , either in the dipp , or in the rise , or streek , as was before noted : so that in meeting with one of these gaes , having considered its nature , and pierced it , the coal will be found in the other side , immediatly touching the gae , but with an alteration of course . now , in these two last effects , since the coal is not totally cut off , it will be worth the inquiry , to find the surest way of recovering the coal after it is lost . therefore , where the coal is not cut off , by a considerable distance , and having pierced the gae , it is not to be found in the other side , you are to consider well the nature of the metals you find approach to the gae , and if they be such , whether stone , or coal , as you know to ly under the coal that you have lost , then you may be sure the coal is to be found above in its course , which is to be traced by the dipp of the metals you find . as sometimes i have seen , when a coal hath been cut off by a gae , happly there is another coal under it fathom , after the gae hath been pierced , and the lost coal not coming near to it in the other side , that hath been found there , by which it was certainly concluded , that the uppermost coal behoved to be there also , though a little back , conform to its course . but , if the metals or coals , under the lost coal , hath not been known , then you are to take notice of the dipp and rise of these metals , you find on the other side of the gae , which you have pierced , and making that your rule , range back over the metals , conform to the direction to be given afterwards , and you shall find the cropp of the coal you want , and after which you were inquiring . where the coal is not quite cut off by the gae , but hath its course only altered , you are to consider , in searching for it , before you pierce your gae , that which the coal-hewers term the vise , or some of them the weyse of the gae , which in effect is nothing else , but a dark vestige of the dipp or rise , that the body which now constitutes the gae , should have had naturally , if it had been perfected ; which when it tends downward , then must the gae be put over that way , and in the other side shall the coal be found , and down , as they term it ; that is , the dipp which it had naturally , augmented . and , if the vise be up , the same way must be taken for piercing the gae , and the coal will be found up , that is , its rise augmented . but these things cannot be made so intelligible , as by seeing , there being many things in the alteration of the course of metals very curious , and worthy of observation : as when a coal is cast down out of its natural course by a gae , and so made sometimes under-level , it riseth as much to another hand , and the cropps go so much farder out , which still makes the level useful , the use whereof would have been judged lost by the down-casting . sometimes a coal made to have four contrary courses , as is evident from the eighth figure , where there being a gae at e , makes it take such another course , in stead of coming out to the grass . sometimes , before the metals overtake the gae , they are made to ly like a bowe ; one instance whereof is visible above ground in some metals lying between bruntiland and kinghorn , at a place called the miln-stone , where there is a small coal with free-stone above it , all dipping to the s e , and rising to the n w. upon the rise they meet with a gae , which is a great whin-rock . in their course to the grass , before they touch the said rock , they take a contrary course , and dipps into it , and are there quite cut off . the manner whereof is to be seen in this tenth figure following . figure . where ab is the rock : ef the coal : cd the free-stone . now , whereas they should have risen towards a , they turn at d , and dipps into the rock , which any may observe in passing that way . many other such motions are observable , which i pass , and leaves them to the observation of the curious . the third thing i promised to speak of , was of damps , and as they are termed by the coal-hewers , ill air. these do deserve a more accurat inquiry into their kinds , their causes , and effects ; then i am capable to make , there being many things in them very con●iderable , and worthy of a narrow search : therefore following the course i have hither to observed , i shall shew my own observations thereof , and leave the more curious search to the spirits fitted for that purpose . this damp then makes an obstruction of respiration in men , or other living creatures , in subterraneous spaces , as caves , coal-rooms , levels , sinks , and such like ; which obstruction proceeds principally from two causes , both which goes under the name of ill air , among the vulgar . the first is the corruption , or putrefaction of the air , whereof there are two sorts ; one is in places where hath been fire kindled , which burns the coal under ground , the smoke whereof , being full of sulphur , and other bituminous matter , and not having free passage to come above ground , filleth all the waste rooms under ground , and infects the air so , that the smell of it , even at a distance , is intolerable , and amongst it no living creature is able to breath . of this there are examples in dysert in fife , and fauside in east-lothian . this was kindled on design by a fellow , who for his pains was hanged in the place , and hath burnt these years , and more , the fire whereof is sometimes seen near the grass , with abundance of smoke , as it runs from one place to another . the second , where the air is corrupted without the mixture of smoke , or any other gross corrupting body , which is the most considerable of all damps , and hath the strangest effects , in killing animals in an instant , and so hath been alwayes most prejudicial in the works , where it is found , many persons having thereby lost their lives , without access to cry but once gods mercy , to some instances whereof i have been witness . i shall not offer to determine about the cause of this damp , but shall give an account of somethings i have observed about it , which when duely pondered , may haply lay a foundation , at least of a probable conjecture , whence it may proceed . this kind of damp then , and ill air , is never found in coal , or other metals , where there is water to be found ; i mean , whence the water hath not been drawn away by a level , or aquae-duct : as in coals , where there is a necessity to lave the water from place to place , or to pump it along the ascent or rise of the coal , to the bottom of the sink , from which it is drawn out above ground , this ill air is not found . nor is found frequently , if at all , in these coals where the water is drawn from the coal by a level , or aquae-duct under ground , till it come of its own accord to the bottom of a sink , which is in place of a cistern , out of which it is forced also above ground , and differs only from the other , that the water runs here of its own accord by a descent to the sink , which is termed a drawing sink : in the other it must be forced by the rise of the coal , because happly , a sink upon the dipp would be of such a deepness , that no force could draw it up in a perpendicular . but this kind of damp is found ordinarily in these coals from which the water is drawn by a level , the beginning or mouth whereof is above ground , and carried along by a right line under ground , till it overtake the coal , which it is to d●y : so that the water which comes from the coal , runs without being forced , and is sometimes so considerable , that it makes mills go , without any other addition , as is to be seen in the earl of wintons lands of seton , where four mills goes with the water that comes from under ground , out of the coal ; which kind of levels are only found where the coal lyes in a field , which hath a considerable rise , or ascent above ground ; there being a necessity to make use of the other two wayes spoken of , for drying the coal , when the field in which it lyes is a plain . further , of these coals , which are dryed by the free-level ( for so they term the level that runs unforced ) there are some to which this kind of damp is more incident , than to others . the cause of which difference is found to be , the solidity and clossness of the metals , whether of coal or stone , wherein some exceeds another . there being some , that are full of rifts , or empty spaces ( i mean empty of any part of the same body where they are ) which will sometimes serve , to convey a considerable quantity of water in place of an aquae-duct or level ▪ which spaces are termed by the vulgar , cutters , which sometimes proves very profitable in the ground where they are found , both in regard of the use they serve for , in stead of level , and for rendring the metals wherein they are found , more easie to work , in making them yeeld easily to the force of the wedge and leaver . other metals there are , wherein few of these cutters are to be found , and if water be to be conveyed through them , there is a necessity of cutting a passage through them for that effect . now , this damp , whereof we speak is sound most frequently , and most violent in the first sort of metals , viz. in these which are full of cutters or rifts , which gives some ground to this conjecture of its cause . these spaces which are found in coal , or other metals , as stone or till , before the coal begin to be dryed by a level , are full of water , which is still in motion , as are all subterraneous springs , whereof some are more violent , some more slow , conform to the passage they have to the fountains above ground , where they discharge themselves . now , for drying these coals , and rendring them workable , there is a necessity to cut a passage , thorow which that water discharges it self quickly , it being large , and admitting a great quantity at once , by vertue whereof ; a great field is drained at once , and the sourse not being able to furnish so much water , as the conduit is able to convey , these spaces in the body of the metals , being emptied of water , must needs be filled with air , which air having little contact and commerce , with the great body of air above ground , and so hath little or no motion , corrupts in these places , and thereby becomes poisonable , so that when any animal is necessitat to draw it , and respire by it , it choaks them on a sudden , just as standing water , which being without motion corrupts , and becomes poisonable , though haply not in so great a degree as the air : the air , being a body much finer and purer , than water , that holding good in it , corruptio optimi pessima . this is much confirmed by what is before asserted , that in the coals , whence the water is drawn , and they drained , but not by free-course , but by force , as pumping , and drawing by buckets , these damps are seldom or never found : because the passage of the water being forced , it does not so suddenly dry the metals , as the other , whereby there is alwayes left in these spaces some water , which being it self in motion , keeps the air also in motion with it , and thereby the air is kept from corruption , at least in such a degree , as it is in the other . hence we find , that in these kinds of coals , the rooms under-ground are alwayes wet , or for the most part they are so : whereas in the other , there will be no water found to wash a mans hands : and sometimes the coal through want of water , becomes so dry , that it cannot be wrought in great pieces , as others , but crushes in the very working , and when wrought , is rendered useless , and will not at all burn . this puts me in mind of a very pleasant conception of a worthy and learned person , doctor george hepburn of monk-ridge , with whom i had occasion one day to discourse on this subject . he is of opinion that the water is the mother of the coal , whereby it is preserved fresh , and incorrupted , and that when the water is drawn off , and this damp follows , it is not the air , which succeeds in place of the water , and is corrupted for want of motion , that occasions it . but as we see , when the corruption of a liquor within a vessel , when the mother is gone , corrupts the vessel it self , and occasions an ill savour or taste in the vessel ; so that the coal being corrupted by the want of its mother , the water ; corrupts the air in the subterraneous spaces , as in coal-mines , sinks , caves , and other such like . he had likewise another pleasant conception about the generation of coal , judging it to be formed gradually out of another metal , as of till , by the help of water , of which he himself may perhaps give an account . and though i be not of his opinion in that matter , yet i must acknowledge , i was taken with it , and shall be glad to see a more full account of it from him , than he had access to do in the short conference we had . the effects of this damp are first , it hinders the burning of all combustible matter , as candle , coal , pitch , sulphur , &c. so that if you take a torch lighted , and let it down to a sink , where the ill air is prevalent in the time , it shall straight extinguish it . or take a coal , which is burning , and let it down , it shall not only extinguish the flame , but shall make the coal in an instant dead , and as cold as never heat had been in it . but the most dangerous effect is , its killing of living creatures , whereby many persons have been suddenly killed . some in going down to a sink , where it hath been powerful , have fallen out of the rope , and perished . others have been choaked , and yet have gotten out by the help of others in a sudden , and have remained a considerable time without the least appearance of life , but yet have at last recovered . yet it hath been observed , that some of these persons that have been so struck with the damp , and recovered , have had alwayes some lightness of brain thereafter , and never so settled as formerly . this i know to have happened to one , whom i have seen so , many times thereafter . what hath been its effects on some animals , whereof you have made experiment , i leave to the account you have given . one thing i shall only mention , which to me seems somewhat strange , that notwithstanding these damps are so effectual , and causeth so suddenly the death of animals , yet the ratts , which are in some of these places , where the damps are most violent , are not reached by them . for sometimes , when they are so powerful , that nothing that lives can enter under ground , without sudden death , yet they continue there , and are not found to diminish , even where they have no access to escape , by coming above ground . or if it should be imagined , they removed to some other place of the ground , where the damp is not , how is it , they are not as quickly choaked with it , as dogs are , and other animals , which at the first encounter are killed ? if it be inquired , how comes it to pass , that in these fields of coals , which are dryed fully ( as was said ) and to which these damps are incident , because of corrupted air that remains within the body of the coal , or other metals , how comes it to pass ( i say ) that they are but sometimes incident , and are not alwayes found ? for clearing this , it is certain , that even in the grounds , where these damps are most frequent , for the reasons above mentioned , yet they are only powerful when the wind blows from such a certain point , as some chimneys , that do only smoke , when the wind is in such an airth . this is so generally , and well known , that the work-men observe it , and when they find the wind in such a point , whence they fear the damp , they will not enter under ground , till trial be made of the air , which they do in sinks , by first letting down a lighted candle , or some burning coals : which if they do not burn , then there is no access to enter . secondly , the wind in which this ill air is most noxious , and hurtful , blows from that point , where the field of coal lyes , that 's not yet wrought , which seems somewhat strange , and yet when duely considered , it will appear abundantly consonant to reason . an example of this is to be found in the coal of tranent and elphingston , the streek whereof goes to the rise of the hill above ground , from ne to sw , as hath been formerly observed . so that the beginning of their level , is at the ne point of the streek , from which the coal hath been wrought up along the streek towards the sw , the wastes lying all towards the ne. yet when the wind blows from ne , or n , or almost from any other point of the compass , they are not troubled with this damp. but if it blow from sw , and blow hard , they are in hazard to encounter it . and though the damp is not alwayes found when that wind blows ( whereof there may be some particular cause ) yet it is never observed in another wind , whether it blow less or more : the reason whereof may probably be , that the wind blowing from other points , as from n , or ne , hath more access to enter the wastes under ground , and move the air that is in them , towards the face of the unwrought coal , whence is supposed to proceed the corrupted air , that lurks in the rifts and cutters thereof , ( from which the water is drawn away , ) and occasions the damp. now this air being moved by the force of the wind , keeps the corrupt air from coming out , it being stronger then the other . whereas , upon the contrary , while the wind blows from sw , it entering the empty rooms , drives the air under ground from the face of the unwrought coal , down towards the old wastes , which have their course from the beginning of the level . by which means , the air , that is corrupted within the bowels ( to speak so ) of the coal , comes out to the wastes , without resistance , it being certain , that fluid bodies , as water , and air , inclines to move towards that place , where they meet with the least resistance . hence is it , that the more direct the wind be , in blowing against the face of the unwrought coal , as is the wind from ne , the ill air is the more repelled and driven back , but the more oblique it be , as are the winds from these points , that are nearest to sw , the air is not so good and free : which difference is known by the burning of candles , they burning with greater difficulty in these winds , than in others , which blow from these points nearest to n , and ne. some are of opinion , this ill air ( in those places we have been speaking of ) comes from the great wastes , that ly above the un-wrought coal , and by strong sw winds is driven thorow the cutters thereof . or the wind blowing from that point , and coming thorow these cutters , brings the corrupted air alongs with it , even as , after a showr of rain , a spait of water comes , and carries alongs with it , both the foul water and the clean , it meets with . though this may be probable , which seems to be your own opinion , yet the other seems to be more probable . the other sort of damp , is that which they call want of air ; and though the term be not altogether proper ( there being no space without some air ) yet there is a want of air , which is sufficient for respiration of animals , or for the burning of fire . this is ordinarily found in the running of mines under ground , for conveying of water from coal , or other metals , or in the waste rooms of coals , where the sinks are very deep , and to evite the charge thereof , there is some necessity to work as far under ground for winning of coal , as is possible , without new sinks . the cause seems to be , that the air under ground , in such cases , wants communication with the air above ground , because it is found , that by giving more communication , the evil is cured . whence comes the necessity of air-holes in levels , which are so many sinks set down , for no other use , but for giving air to the workers ▪ some are of opinion , that this defect might be supplied by the blowing of bellows , from above ground , through a stroop of leather , or of some other thing , which must run along to the end of the level , for keeping the air there in motion . but i have not yet heard , that it hath been made practicable . the effects of this damp are not so dangerous , as these of the other . 't is true , it will kill animals , and extinguish burning coals and candles , but not so suddenly as the former ; and so people are not so readily surprized by it . the other seems to kill by some poisonous quality : in this animals dies for want of sufficient air for respiration . therefore in advancing in a coal room , or level where this is , you shall see the flame of the candle grow less and less by degrees , till at last it be totally extinguished , and the person entering , shall find the difficulty of breathing grow greater , as he advanceth forward , till at last he cannot breath at all . hence it is , that few or none are killed by this kind of damp , and all its prejudice is , that it renders the work more chargeable , when there is a necessity to remove it . for that , which they call wild-fire , it being a thing not incident , but to very few coals , is less known , than any of the rest of the accidents that follows coals . the account i have heard of it , is , that in some coals , which naturally are full of oil , and that are ( as they call them ) fa●t co●ls , there is a certain fire , which is as a meteor , and i judge , that from its resemblance to ignis fatuus , which the vulgar termeth wild-fire , it hath the same name . it seems to be composed of some fatt oily vapour , that goeth out of the coal , the pores thereof being once opened , which is kindled after the same manner , as those fires above ground are , which are most ordinarily found in fatt , and marrish ground . of this fire it is reported , that in the day time , while the work men , are working in the coal-roomes , it comes to no height , though it be sometimes seen in little holes of the coal-wall , shining like kindled sulphure , but without force : but when the work-men are once removed , and have stayed out all night , it gathers to such a strength , that at its first encountering with fire , which the coal-hewers are necessit●te to have , by taking in of light , it breaks out with such a violence , that it kills any person , it finds in its way . the reason , why it is without this force , while the work-men are in the place , seems to be this , that they working with such violence , and motion as they do , do certainly move the air considerably , it being contained in so narrow a place , as a coal-room . and this air being violented by motion , moves that oily vapour , whereof the fire is formed , so that it gets not liberty to unit it self , being dissipated by the motion of the air. but so soon , as the air is still , and quiet , after the work-men are gone home , it units it self , and gathers force , and therefore , so soon , as it meets with fire , which is more forcible , than the flame that is kindled in it , it rarifieth ; the sulphurious parts being kindled , and forceth it self out , as powder out of a gun. for it hath been observed , that if any person stay in the coal-sink while it breaks within the coal-room , they are in danger of being killed . the ordinary way by which the hurt of it is prevented , is by a person that enters , before the work-men , who being covered with wet sack-cloath , when he comes near the coal-wall , where the fire is feared , he creepeth on his belly , with a long poll before him , with a lighted candle on the end thereof , with whose flame the wild-fire meeting , breaketh with violence , and running alongs the roof , goeth out with a noise , at the mouth of the sink , the person that gave fire , having escaped , by creeping on the ground , and keeping his face close to it , till it be over-passed , which is in a moment . the place , where this was most known , was in a coal be-west leith , in a piece of land called werdy , which for want of level , and the violence of that fire , the owners were forced to abandon . i come now to the last part , which i promised to speak of , namely of the best way for trying of grounds , to find coal , where never any hath hitherto been discovered , and of carrying on of levels , for draining the water of coals and making it workable . as to the first part , there are but three wayes . first by sinking , which is most chargeable , in regard , that in such grounds , where the metals are all intire , water abounds , and this doth not only bring the master under a necessity of great expence for drawing the water , but also rendereth it impossible to get sinked to any deepness , which may suffice , for giving an account of all the metals to be found , within the field , that may be rendred workable . there was a second way invented to supply this defect , which is by boaring , with an instrument made of several rods of iron , which boareth thorow the metals , and tryes them . this way in my opinion , is worse then the former . for first , if the coal ly deep , in the place where you try by boaring , it becomes almost as tedious , and expensive , as sinking , the drawing of the rodes , consuming so much time , in regard it must be frequently done . next , in boaring , suppose the nature of the metals , be found , yet thereby their course can never be known , till they be sinked , which is one of the things most considerable in the search of a coal , because thereby is known , whether it be workable , with advantage or not , and whether it be possible to draw water from it by a level , or otherwise . lastly , this way leaves the master at an uncertainty ( notwithstanding the coal had been found ) of its goodness , as to its nature , and as to its thickness . as to its goodness , because all that is found of the coal , by this boaring instrument , is some small dross , which remains after the washing of the thing that 's brought up in the wumble , by which none can judge of its goodness , or badness . as to its thickness , because it is impossible to discern exactly , when the boaring-instrument hath passed the coal : all the rule for trying thereof , being the kind of metal that is brought up in the wumble . now , i have known in my experience a coal boared , which the b●arer by that rule hath judged four foot in thickness , yet when it came to be sinked , hath not proven one . the reason whereof , is obvious , because the boaring-irons , being long , and weighty in lifting them up , and down , they break the coal , already pierced ; and this falling down among the metals , they are piercing , and being found in the wumble with them ( especially when the metal under the coal , is a black till ) gives g●ound to imagine , that all that time , they have been peircing a coal , and so consequently , the coal must be of such a thickness . the last , and best way of trial , is that which is termed an ranging over the metals . for doing whereof , this method , is to be observed . suppose there be any place within in the ground to be searched , where the course of metals can be seen , as in the banks of a river , or rivolet , or sea-banks , when the place is near the sea , then consideration must be had how far the lowest of these metals , can go before they crop out to the grass , which will be known by observing the dipp or declination of the metals , and the rise of the ground above , whereof a just allowance must be given , and having digged before the said crop , you shall certainly find , the metal , that is next under it , and if that prove not coal , keeping the former proportion , you must advance , and digg before its crop , and so shall you find , the next metal under it , and so still , till you have tried your ground , and found the crops of all your metals within it . but if there be no water-banks , or such like , to give you the first view , of the course of your metals , then must you sink first at random , and having once past the clay , you will readily overtake some metals , whereby you will know the course of the rest , and having once found the dipp and rise , you must follow the method of ranging already prescribed , except the ground so to be tried , contains not within it self the crops of the metals , the body whereof lies in it , whether of coal , or stone , in that case , there is no way to try , but by sinking , or boaring . the way of ranging is conspicuous in the following figure . figure . the piece of ground to be tried , is pn , where there are several seams of metals , that cropps out at the points klmn . suppose the lowest to be the coal , viz. in , for which you are to make trial . you digg first at k , without the cropp of the seam fk , and you dig till you find the other seam of stone gl , at the point c. following the rule before given , you advance before its cropp , and diggs at l , and finds the other seam of stone hm , at the point d : from which you also advance , and diggs before its cropp , at the point m , and finds your coal at the point e. but , if by advancing over the cropps of these metals , which comes out from under one another , you find no coal ; then you are to range backward , for the cropps of metals lying above these , where haply the coal may be , as at o , and p. this in my opinion , is the most certain and exact way of trying fields for coal , or any other metal of that nature , and least chargeable of all others . the second of this last part , i promised to speak of , was in order to levels , or coal-mines , which are nothing else , but conduits or gutters made under ground , for conveying of the water from the coal , and so rendering it workable . it seems that a very little time before this , that way of mineing under ground hath not been fallen upon . for there are to be found coals wasted in their cropps only ; for conveying the water whereof , they have made a conduit , or level , which hath been open to the surface , like a great ditch , some whereof have been ten or twelve fathom in their deepness . the beginning of the level ( to keep the term used ) must alwayes be at the lowest part of the field , where the coal lyes to be dryed . some whereof , by the rising of the ground , and the streek of the coal rising that way ( as we shew before ) gives the advantage of a free level , that is , when the water comes above ground of its own accord , without being forced by drawing . in others , there is a necessity of engines to draw the water from the lowest part of the level , and bring it above ground ; which engines are of several sorts . as when men draw with ordinary buckets , or when there is a horse-work , or water-work , and that either by a chain with plates , and a pump , or with a chain and buckets ; all which are very common , especially those we have in scotland , they being capable to draw but a very small draught , making only use of one sink for that effect . but there are to be seen in the north of england , in bishoprick , water-works , by which water is drawn above fathom in perpendicular , but not all in one sink . the manner whereof is thus , there being a sink from the end of their level , to the surface of the earth , where their works are going , fathom deep , which must dry the coal-sinks at or , which ly above the banks of the river , where the water-works are scituated , there is first one fathom deep from the grass . another in a right line from that , of . another of ; upon all which there are water-works . in the first sink the water is drawn from the bottom fathom , and thence conveyed into a level or mine , which carries it away to the second sink . by the second work , the water is drawn out of the second sink fathom , from the bottom , and set in by a level to the third sink , which being only fathom deep , the water-work sets it above ground . the form of the engine is after this manner . in the first sink there is an outter-wheel moved , as other milns are , by the water of the river : upon the end of the axle-tree of which wheel , there is a ragg-wheel , turning vertically , as doth the outer-wheel . this ragg-wheel by a nutt , or trinle turns another , which moves horizontally , the axle-tree whereof goes right down in the sink , and may be is or fathom ; at the end whereof there is another ragg , which by a nutt turns another wheel , which goes vertically as the first ragg , and causeth another wheel with a long axle-tree turn as the first , and so down till it come to the wheel , which turns the axle-tree , by which the chain is drawn . the second sink , hath such another engine , but not so many wheels , in regard it is not so deep . the third , hath only one single wheel , whereby the water is drawn above ground . the most curious of these engines , that are to be seen , are at ravensworth near to newcastle , which belongs to sir thomas liddel , a most ingenious gentleman , who , for procuring a fall of water , which may serve the wheels of all the three sinks , hath erected the first work upon pillars like a wind-mill , pretty high above ground , from which the water falling , makes the second go closs above ground . and to make the water fall to the third , the whole wheel is made go within the surface of the ground , which terminats at a river under the works , which mine is of a considerable length . where water cannot be had to make such works go , they use horse-works , but not with so good success , being more chargeable , and not having so much force and power , as the water-works . but i am of opinion , that wind-works might serve well , where water cannot be had ; and when no wind should happen to blow , the same works might be supplied by horse : and that the wind , when it blows but ordinarily , hath as much force , as so much water , which is made use of for turning such wheels , is to me unquestionable . for i have seen in holland , a wind-mill , that by the motion of the outter-wheel , caused seven pair of mill-stones to go at once , besides another motion for bringing the victual from the ground , four or five stories high , to be grund . and several saw-mills , which besides six or seven great saws , they caused go , did by another motion bring up from the water great trees like ship-masts , to be sawen , and placed them right against the saw ; all which could not be but of greater weight , than or fathom of chain with buckets , or plates for drawing of water . but to return , for the right making of a level , the true hight of the ground , where the coal lyes must be first taken , that it may be known , how much of the field can be drained by it ; which must be done , either with a quadrant , or with an instrument made express . then care must be taken , to take the lowest part for the mouth of the level , that the field can afford , and from that it must be carried in a straight line towards that part of the field , where the coal is thought to be encountered by the mine . in working whereof , two things are in a special manner to be reguarded . first , that the level be wrought without ascent , or descent : the best way for trying this , being by the surface of the water passing through it , which ought to be as little moving , as can be : for the loss of one foot of level , which the ground gives , is a loss of a considerable parcel of coal to be digged , especially if it be state . if there occur any metals , which are impregnable , in the course of the level , so that it is impossible , to follow so straight a line , in regard the mine must be wrought over the top of that stone , which is unworkable , in that case , there is but one of two to serve the loss of level ; either the coal rises in streek towards which the mine is carried , and if that be , then after that stone is past , the level must be carried , as low , as it was before it encountered the same , and the course of the water shall not be obstructed , because the sourse , viz. the coal from whence the water comes , rising higher than the stone , the water shall easily pass over that hight . hence it is , that we see in some coals , that have been wrought , at the lowest point of their streek by a drawing-sink , and the streek rising from that point , the water that hath come off the coal , being in its sourse higher , than the mouth of that drawing-sink , hath made it to over-run , and serve to discharge all the water , that comes therefrom . but , if the mine be run to a coal , that after it hath overtaken it , rises no higher in streek , than the mine it self , the water that comes from it , will not pass over any hight in its way , but will be unquestionably stopped . therefore , in case such an impediment could not be removed , as many times such metals will fall in , which are unworkable in a direct line , the use of a siphon might be tried , which would unquestionably supply the loss of about foot of level , this being the hight in perpendicular , to which the pressure of the air , is able to raise water up thorow a siphon . the next thing to be observed in carrying on of levels , are the air-holes , for which there is a necessity indispensable . in setting down whereof , care must be had , that they be not directly upon the mine , lest rubbish falling thorow from above ground , should stop , and obstruct the same , and so obstruct the course of the water ; and therefore it 's better they be set down at a side , their only use being to communicate fresh air to the work-men , which if it could be otherwise supplied ( as i think it not utterly impossible ) would render the charge of the coal-works a great deal more easy . other things might be spoken to of levels , as that some run with the course of metals , they pass thorow ; and that some run against that course ; and of bringing level from the dip of an upper-coal , which hath a level of its own , to dry a coal lying under it , which cannot be otherwise done . but these things being common and obvious to any , who have but the smallest skill and experience , i shall forbear . this confused account , your importunity hath drawen from me , for which if your book suffer censure , which i grant it may do , as to this part of it , you are to blame your self , and so i rest and am , &c. finis . a discourse of gravity and gravitation, grounded on experimental observations, presented to the royal society, november . by john wallis ... wallis, john, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) a discourse of gravity and gravitation, grounded on experimental observations, presented to the royal society, november . by john wallis ... wallis, john, - . royal society (great britain) [ ], p. printed for john martyn ..., london : . reproduction of original in huntington library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng gravity -- early works to . gravitation -- early works to . physics -- early works to . - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - judith siefring sampled and proofread - judith siefring text and markup reviewed and edited - pfs batch review (qc) and xml conversion at a meeting of the council of the royal society , ianuary . / . ordered , that a discourse , made before the royal society , the th of november . by dr. john wallis , concerning gravity and gravitation , grounded on experimental observations , be printed by the printer of the royal society . brouncker , pres. r. s. a discourse of gravity and gravitation , grounded on experimental observations : presented to the royal society , november . . by john wallis , d. d. a member of that society . london , printed for john martyn , printer to the royal society , at the bell in st. pauls church-yard , . a discourse of gravity and gravitation , grounded on experimental observations , presented to the royal society , the th of november , . in compliance with the commands of this royal society , in order to the promoting of experimental philosophy , to present you a philosophical discourse , either grounded on , or leading to , experiments ; the subject i have chosen for this discourse , is that of gravity : the being and effects of which , is no otherwise known to us than by experience , or discourse grounded thereupon . the subject is copious , and therefore i must single out some few experiments out of a great many : and they shall be the most simple and unperplexed in their kind , that the inferences may be the more clear and perspicuous ; and such experiments onely , as are either commonly known , or have already been made before you , or may easily be , whensoever you please . i will not dispute the nature of gravity or gravitation , what or whence it is ; whether from a quality within , or a pressure from above , or a magnetick traction from below : but shall take for granted ( what every days experience testifies ) that there is , ( at least in this our sublunary world ) such a thing as gravity and gravitation ; whereby those we call heavy bodies , have a natural propension to move downwards ( towards the earth , or its center ) if not hindered by some more potent , or at least an equivalent , strength . this motion downward , we call descent ; the endeavour so to move , we call gravitation ; and the principle from whence this endeavor proceeds , we call gravity . and things are said to be more or less heavy , as they have more or less of gravity : which may be understood , either extensively , according to the quantity of it ; as when we say a pound is heavier than an ounce , though that be feathers , and this be lead : or intensively , according to the degree ; as when we say , that lead is heavier than cork , or quick-silver than water ; that is , gradually heavier , proportionably heavier ( bulk for bulk ) or ( as it is now wont to be called ) specifically heavier . i say , the endeavour thus to move , i call gravitation ; though by reason of some impediment , there be not any actual descent . ( and it is allowed me , by those from whom in some other things i differ , that not onely motus , but conatus ad motum , is properly gravitation . ) which i thought necessary thus to define , that i be not misunderstood in the sequel . but i add further , this endeavour of descent , implies an aversness to ascent , with equal force ; and that the one and the other are equally the effects of gravitation . this gravitation , or endeavour to descend , is one kind of strength ; and may be opposed not onely by a contrary gravitation , but by any opposite strength whatsoever ; whether by way of impediment onely , or of contrary force . for , though there be divers kinds of strength ; yet they are all thus far homogeneous , as to be compared each with other , as equal or unequal , greater or less , and that in any proportion . thus the gravitation of the scale a ( in fig. . ) may be opposed , or hindered of its effect , by a contrary gravitation at b , ( supposing all the tackle strong enough ; ) or by a force under it , which thrusts it up ; or by a force above it , which pulls it up , ( or doth at least endeavour so to do ; ) as , for instance , that of a mans hand . every of which , being contrary forces , if equal to that of gravitation at a , will stop its descent ; if less , they will retard it ; if greater , they will force it upwards : not by making it cease to gravitate ; but by defeating the effect of that gravitation . but it is opposed also by the strength and stiffness of the beam ; ( for if that either break or bend , a descends : ) and by the strength , though not the stiffness , of the strings that hold it , ( for if they either break or stretch , the weight will descend , at least in part ; ) or by the hardness , strength , and solidity of the floor or table on which it rests ; which , if strong enough , will support it ; or , if the medium be viscous , this viscosity ( which is a degree of solidity ) will at least retard its descent . all which do oppose it , not as contrary forces , but onely as bare impediments : which , if strong enough , do hinder the descent ; but , though more than so , do not thrust it up . but if the medium be supposed perfectly fluid , in every point , without any aversness to separation ; it may hinder , or retard the descent of a , by a contrary force , or contrary gravitation , ( it self also endeavouring a descent by its own gravity , or at least to preserve its station , against an ascent ; ) but not as a bare impediment from its solidity , firmness , or aversness from separation ; which is supposed to be none . it hath a resistance to motion , not , to separation . and of such heavy fluides , i intend principally to discourse , and of solid consistent bodies , onely with reference unto such . if it be objected , that there be no such perfectly fluid bodies ; but that those which we call fluides , are either made up of very fine , but disunited , atoms , ( each having its own shape and figure , though very small ) as the atomists suppose ; or at least in some degree unctuous and viscous : i will not dispute that point , as not now necessary ; but only express what it is i mean by fluid or liquid bodies ; and the nearer any thing comes to such a condition , the nearer it is to perfect fluidity . and where such viscosity is very little and undiscernable , we consider it as none at all . and even that which is , if it be not stronger than the incumbent weight can break , it doth not wholly hinder the descent , but onely retard it : the weight sinks , though not so fast . now , there is in all heavy bodies ( whether firm or fluid ) and in every part of them a prospensity , not onely to a direct descent , but ( if that cannot be obtained ) to an oblique descent , according to any declivity . ( for a river will run down-hill , and so will a bowl also ; and a sloping pole , if not supported , will fall obliquely . ) which i the rather note , because i find some to put a great stress on the lateral gravitation of fluides , as peculiar to them ; without taking notice , that the same is common to solides also : the difference being but this ; in fluides the parts be separable , but not in solides : but the tendencies are in both the same . now , of fluid bodies it is that i intend principally to speak . of which the first and great phoenomenon is this , that they will ( if undisturbed ) reduce themselves , by their own weight , to a level ; that is , to an horizontal plain , or what as to sense is such ; and will so continue , if either not pressed at all , or equally pressed on all parts . as if the surface , by any means , be undulous , as abab , ( in fig. . ) the prominences at a , will sink to fill up the cavities at b , till all come to the level of le. and this they will do , partly by spreading abroad , and flowing into those cavities as lower places : and partly ( the whole being fluid ) by pressing down what is under a , and pressing up what is under b ( in fig. . ) for though onely the former of these would happen in case all under le ( in fig. . ) were a firm solid surface , ( like as when water overflows the dry ground , and fills up all the furrows ; ) and onely the latter , in case such prominences ( whether one or more ) were contained within solid pipes , ( in fig. . ) so as that they could not flow laterally into the adjacent cavities : yet in the present case , where both occasions happen , both causes will operate . for nature doth not work by election , but ad ultimum virium , and all the ways it can , where one doth not oppose the other . and like as if a vessel have two holes , the one at the side , the other at the bottom ; the water will run out at both : so the prominences at a , being not hindred of either , will partly by lateral fluxion , partly by direct depression , fill up the cavities of b ( in fig. . ) it 's true , that a solid body , having opportunity of both , because ( by reason of the coherence of parts ) it can move but one way , will move that way only which is most declive : but a fluid body , being partible in every point , divides it self every way , as there is opportunity . now , such fluid body being thus reduced to a level , if undisturbed , it will so remain ( in fig. . ) for there be now no prominences , as at a , ( in fig. . ) to sink or flow down ; nor cavities , as at b , to receive them : nor is any part of it more pressed than other , whereby that should sink , or this rise . but if at some part , as at d , ( in fig. . ) by weight or other force , it be pressed , but not in others ; or more at d , than at others ; it will at d subside or be depressed , and rise elsewhere , ( in fig. . ) and what is thus shewed of the level le , holds equally of any other level , as f g. within the fluid , at what depth soever , ( in fig. . ) if all parts of it be equally pressed , it keeps its level ; but if some parts of it be more than others , those will subside , and these rise : because the weaker force must give way to the stronger . the like happens in a syphon inverted , ( in fig. . ) where if the water be higher in the one leg at a , than in the other b , that will sink , and this rise , till they come to a level at le : and when so , it will there rest , if there be no other force to put it in motion . so in an ewer , ( fig. . ) or other vessel with a nose ; the water in the vessel ( if higher ) will sink it self , till that in the nose be raised to the same height ; if that in the nose be higher , this will sink , and that rise , till they come to a level at le. the reason of it ( if we do not study to perplex the phaenomenon ) is very evident : because , while the fluid ( supposing it uniform ) stands at the level le , no part of the same horizontal plain , at what depth soever , is more pressed than other , whereby it should be inabled to thrust any other out of place . upon the same account , that of two scales equally charged , neither can descend , or force up the other ; but do mutually sustain each other in equipois , and are at rest . for though both do ponderate , yet neither doth preponderate . and no power is able to over-bear another power , unless stronger than it . but in case the fluid be higher at a than at b , the parts under a are more pressed than those under b ; and therefore those thrust these away . on the same account , that if the scale a be heavier charged than b , though both press downwards ; yet the heavier prevails , and forceth up the lighter . for , of contrary powers , the greater always over-powers the lesser . it will yet be not amiss , ( that i may not in the sequel be mistaken ) to give notice by the way , that what i have said of this level in heavy fluides , is not so to be understood , as if this level were in all cases mathematically exact : for , though it ought so to be , if nothing else did intervene than what we have hitherto taken into consideration ; yet many times some little accidents do disturb it : as , when a drop of water , on a dry board , keeps a convex figure , either because of some little viscosity therein , or as shunning the contact of that dry surface ; and quick-silver in a glass-pipe , or like vessel , will have a visibly convex surface , as shunning the contact of the glass ; and the like would happen in water , if the glass were greasie . and contrary-wise , the surface of water in such a clean vessel would be rather concave ; and so , i suppose , would be the surface of quick-silver if the glass were guilded within , because of its easie application of it self to gold. it is observable also , that water in very slender pipes , will rise visibly higher than the surface of that in the broad vessel ; because the air can more conveniently apply its pressure on that broader vessel , than in the slender pipe. and fluides will many times , upon motion , retain an undulation , or dancing up and down , sometimes above , sometimes below , the true level , for a considerable time before they rest : upon a like reason , that a pendulum will swing back and forth beyond the perpendicular on either side , not by its weight simply considered , ( which would rest precisely at the perpendicular , without rising on the other side , ) but by reason of its contracted impetus . but these and other little inequalities , which are to be accounted for from divers accidents , we here neglect ; and consider onely , what would be the result of the gravity and fluidity , freed from such other accidents , too copious here to be insisted on . our meaning therefore is , that ( setting aside other accidents ) a fluid body , will , by its gravity , reduce it self to such a level ; and being so reduced , will so by counterpoise preserve it self , if not disturbed by other force . but it is here objected , that water upon water doth not gravitate , ( and the like of other not-springy fluides ; ) because an element ( say they ) doth not gravitate in its own place . and , for instance , they tell us , that a man under water , feels not the weight of the water over him , ( in fig. . ) before i directly answer this objection , i have this to say to the principle they alledge : that the intendment thereof at first , was no more but this ; that the tendency of a heavy body , being to the earths center ; when there it is , its heaviness ( if not otherwise pressed ) will not endeavour any further motion ; ( for , to move further , were to move from the center : ) and accordingly , if the tendency of any other body be to a certain place , as its term ; when there it is , that principle will not endeavour a motion from thence ; ( for , so to do , were to move contrary to its own nature : ) and if it be carried further , it must be from some other cause , ( as when a pendulum swings beyond the perpendicular , it is not from weight simply considered , which would there have stayed ; but from an impetus imnpressed by a precedent motion . ) and thus far that principle is just and good . but the objection perverts it to a sense never intended by the first introducers . next , i would ask ; what is meant by the waters own place ? and particularly , whether water in a pond , artificially contrived on the top of a tower , be in its own place ? if so , then , though a hole were in the bottom , it ought not to run out . if not in its own place , then the reason fails ; for even there a diver shall no more feel the weight of the water , than if in the thames . so that it is not its being in its own place , but somewhat else , that makes the weight not to be felt . to avoid this therefore , and the like instances ; they now explain their meaning to be , that it doth not gravitate on any thing which is not specifically lighter than it self . and to this explication it is that we are to apply our answer . but neither will this hold . for it is manifest ( to use an ordinary instance ) that a vessel pierced near the bottom , ( in fig. , . ) will run with a fuller and stronger stream , than if at the middle , or near the top ; and more when it is full , than when half out , or almost empty . which argues a pressure of the upper parts upon those near the vent . and to say , they press not on the intermediate parts , but onely on the air without ; is a meer evasion . for the remoter parts of the water cannot press that air , but by pressing that which is between ; like as in a crowd , he that is at a distance cannot thrust him that is at the door , but by thrusting those that are between : and , with a pole , we cannot thrust that at the end of it , but by thrusting the pole : nor , with a rope , draw that which is fastened to it , but by drawing the rope . where yet there is a signal difference between trusion and traction . in trusion , it sufficeth , that the thing be contiguous , though there be no connexion ; but in traction there must be a connexion , and that strong enough ; else the string will break , and the weight not follow . and though a heap of sand will suffice to press down the scale ; yet a rope of sand will not serve to draw it up . and therefore mr. line 's funiculus ( in his explication of the torricellian experiment ) must have somewhat of texture ( as well as contiguity ) to give it strength ; without which it will not be able to sustain the weight of the suspended quick-silver . but certainly , if the parts of a fluid be able to draw one another , much more will they be able to thrust one another ; that is , the one to gravitate upon the other . it is therefore much more conceivable ( in the inverted syphon ) how the water at a ( fig. . ) should thrust up that at b , than how the air at e ascending , should draw up the water at b , and thereby draw down that at a. for , in the first case , there needs only a contiguity ; in the latter , there must be a connexion of all the parts . and therefore if we should allow , that mr. line 's funiculus , or rope of sands , if granted , would equally solve the phaenomenon , by way of traction ; yet , since the hypothesis of trusion ( as is acknowledged ) will do it also ; it is much rather to be chosen than that of traction , by a rope of ( sands , shall i call it , or a rope of ) nothings . but further , it is confessed by a very learned author , the author of two treatises ; the one intituled , an essay touching the gravitation or non-gravitation of fluid bodies ; the other , observations touching the torricellian experiment , ( who is pleased to conceal his name ) that defends the funiculus , and denies our hypothesis ; that not onely water , but even oyl in the pipe a , ( fig. . ) will force up the water at b : and if ( the pipe being empty ) oyl were poured on b , it would force up water into the pipe a ; not to a level , but to an equipois ; that is , ( as his own words are ) to such a proportion of height in the tube , as will countervail the weight of a like cylinder of oyl ; and gives the same reason for it , that we do ; the disparity of pressure causing motion or elevation of the water , in that part nor equally pressed . so that here , a lighter body doth gravitate on a heavier ; oyl , upon water : and that not onely ad pondus , but ad motum , as himself admits ; that is , ( in our language ) it doth not onely gravitate , but pregravitate ; not onely weigh , but out-weigh . so that here , the notion of a fluid not gravitating on a heavier than it self , or one as heavy , is quite destroyed . and it is manifest also , that not the level , but the equipois , is that which is here attended . for the surface of the oyl without the pipe , because specifically lighter , will be somewhat higher than that of the water within it ; and just so much as to make up the equipois . and , contrary-wise , if that in the pipe were oyl , and that without it were water ; that within the pipe would be higher , and in such proportion higher . the same would be , if that at b were stagnant quick-silver , and that in the pipe a were oyl or water , or some lighter fluid . a pound of water poured into the pipe , would it self stand higher , ( because it would take up more room ; ) but would raise the stagnant quick-silver just as high , as if a pound of quick-silver had been poured on ; without any respect had to the specifick gravity or levity and a ship laden , ( fig. . ) will draw just as much water , if laden with so many hundred weight of timber , as with so many hundred weight of lead ; though that be lighter , and this heavier , than a like quantity of water and a piece of wood ( fig. . ) though lighter than water , yet doth not float on the very top , but sinks so far into the water , till it possess the place of so much water , as is of equal weight with it self ; that is , till the horizontal plain , passing by the bottom of the wood , be in all places equally pressed , partly with wood , partly with water . which being known experiments , and confessed on all hands , do quite destroy the notion of non-gravitation of fluids on what is not specifically lighter than themselves . and himself grants , ( essay , p. . ) that air in a bladder , doth gravitate on water . to avoid the pressure of these evidences ; it is now alledged , that the oyl or water in the pipe a , ( in fig. . ) though not intrinsecally heavier , yet it s higher position gives it an accidental weight more than that in the vessel ; and hence it comes to pass , that that doth depress this. but he doth not consider , that this doth destroy the whole design of his second chapter ; which is to prove , that c doth not gravitate on d , nor d on e , in fig. ; that is , that the upper parts of the water do not gravitate on the neather . whereas , if meerly a higher position will make it gravitate ; and that not onely ad pondus , but ad motum also ; then must the water be in perpetual motion , ( the upper parts still pressing away the neather , like as , on another account , it happens in boiling water ; i mean when the fire is under it : for , if it be heated by fire above it , the case is much alter'd ; ) which perpetual motion , the said author there urgeth as a great absurdity . yet i am not ignorant , that mr. boyle is indeed of opinion , that in all fluids the minute parts are in continual motion ; ( making this the specifick nature of fluidity , as contradistinct of fixedness ; ) but that is on another account , and concerns not this point at all . it is not therefore safe for our antagonist , to ascribe it onely to the accidental weight of an higher position . nor is it sound so to do . 't is true , that a different position may give to the same weight a different ponderation : as , for instance ; a weight at g , ( in fig. . ) will ponderate more than at h ; not , because higher ; but , because , at g , it is to descend directly ; but , at h , on an oblique plain ; which abates its force , and doth more abate it as it is more oblique . and a weight at rest in f or e , is of less force to move the balance , than when from a it falls to e ; and less there than when it is fallen to f ; and even this less , than if it had been violently thrown down : because , in the latter cse , there is a greater contracted impetus . again , at e or f , it will ponderate more than at i or k ; because those suspended at a , are at a greater distance from the center c , than those suspended at d : the different position , in all these , and many other the like cases , giving to the same weight an accidental additional force . but a higher position , meerly because higher , gives no such advantage at all : the weight at e being but just of the same force , as at f ; and at i , as at k. for the length or shortness of the string on which it hangs , doth not at all alter the weight : as is agreed by all ; and experience testifies . the reason therefore of this phaenomenon is not , because that at a in a higher position , is of a greater weight than a like quantity at b : but , because the parts at c , ( in fig. . ) are more pressed than those at b ; ( as bearing the weight of ca , which b bears not : ) whereby c is pressed down , and b thereby pressed up . but , against this explication , he brings an experiment on w ch he lays great weight . a porringer filled with lead , &c. which in the air , as at a , weighed ounces ; weighed in the water about ½ ounces ; and the same weight it held ( with some inconsiderable difference , which he excuseth ) whether at c , the depth of or inches ; or at d , the depth of but , or scarce inch , ( fig. . ) where he attempts the account of two phaenomena : first , why it weighs less in water than in air ? and secondly , why it weighs alike at several depths in water ? why it should weigh less in water than in air , he ascribes to the resistance and crassitude of the water : and he tells us elsewhere , that , if we strike with our hand the surface of water , we shall find its resistance not much less than if we struck a board . by which , if he mean the viscosity , or resistance to separation , he speaks not to the present purpose : for , as to that , it is to be so far considered as a firm body , not a fluid , which is that we are now speaking of . but if he mean , a resistance to be displaced , and thrust upward , to make way for the porringers descent ; he says just the same thing with us : for such resistance is properly gravitation ; and doth countergravitate to that of the porringer , and take off so much of its praegravitation . just as when the scale b , ( fig. . ) by its gravitation resists the descent of a ; because a cannot descend without the ascent of b , to which by reason of its gravitation it is averse . and because the porringer cannot descend but by thrusting up so much water , the water must needs give so much resistance to this descent , as it gives to its own ascent ; that is , so much as the weight of the water that must ascend ; and hath just the same effect as if so much water were put into the scale b. and just so much , the porringer weighs less in the water than in the air. and as to what he says of the great resistance which the hand finds , when we strike hard on the water ; we are to consider , not onely the weight of the water , but the swiftness requisite to make way for the hand moving so fast : like as if a weight of pounds hang in the air by a thread ; the least touch of the finger will move it , slowly : but , to move it times so fast , will require a force times as strong : and , if you strike it hard with a swift stroke of the hand ; that which made very little resistance to a gentle touch , will considerably withstand the stroke of a swift hand : not , because the weight is times heavier than before , or doth times as much resist motion ; but because it doth times as much resist a motion times as swift . now , so much strength as is requisite to move so much water with so much swiftness as is necessary to make way for so swift a motion of the hand ; so much resistance must the water give to such a stroke , from its own gravity , without the assistance of the supposed crassitude or viscosity . but when in the present case we consider , how much the porringer weighs in water ; we consider onely , whether it remove so much weight , though never so slowly ; not , with what swiftness it will remove it ; and , as to that , a very little weight more than what it moves will suffice . but his main objection lyes in the other point , that the porringer weighs as heavy at d , the depth of or but of inch ; as at c , the depth of or inches , ( fig. . ) and just so , say i , it ought to be . for every thing weighs in water just so much as its weight is heavier than so much water . as , for instance , if the plain δδ , ( fig. . ) be in all parts equally pressed ; it is , confessedly , the same as if not pressed at all : ( for , so long , there is no reason why one part should rise , rather than another : ) and so it would be if d were just as heavy as so much water . but if d be heavier , then is that part of it over-charged , just so much as d is heavier than so much waters as would fill the place if this were absent : and therefore , if not relieved by so much weight in the scale b , it will sink . and just so much will serve at c ; that is , it must weigh equally , whether at the depth of c , or d , or any other depth . but , saith he , if the incumbent water do gravitate on d , it will more gravitate on c , because at a greater depth . true , it doth so : but , as the pressure at c is greater than at d ; so is the counter-pressure at χ more than at δ ; and just so much more . so that whatever was the pregravitation at d , must be the pregravitation at c also . ( and it is the pregravitation onely , that is weighed . ) just as when the scale a outweighs b by ounces , and into each scale you put pounds ; it will yet outweigh , but just ounces , as it did before . so that his argument from this experiment , will not hold against us . and the solution he gives , will hold as little . it is ( saith he ) because the porringer drives up no more water out of its place at the one station , than at the other . but this is a mistake . for while the pillar α c , ( fig. . ) to make room for the porringer , drives away the water from c to χ , that at χ thrusts up all above it as high as α , to make room for it self ; as α d doth all that over δ : so that the water displaced , is not the same in both . and therefore the porrigner , if not assisted by the incumbent water , would not equally weigh in different depths ; contrary to his own experiment . which therefore makes against himself . but the great plausible objection is , that a man under water feels not the weight of it . and why ( saith he ) but because mans body being heavier than so much water , the water doth not gravitate on it . but this reason is ( as the schools speak ) non causa pro causa . if the question were , why the water doth not raise the body , ( as it would do so much wood ; ) the reason had been good ; because so much water doth not press downward more than the body doth ; and therefore is not able to press it away . but when the question is , why a man doth not feel it ; that is , why he is not hurt by it , or put to pain ; the answer , because specifically lighter , will not serve . for , . a man , by this reason , should not feel the weight of wood , because proportionably lighter than himself : yet we find a man will as much sink under a load of wood , as a load of lead , if of equal weight . and if it be said , this is , because , though the man be not , yet the air about him , is lighter than that wood : i say , it is so ; but this should therefore cause onely a lateral pressure on that air , not a direct pressure on the man. and , though a man stood up to the neck in water , he should yet find the burden of the wood laid on his shoulder ; notwithstanding that both the man , and all about him , be proportionably heavier than wood. and he shall equally feel it , as if it were an equal weight of lead , if both be above the water . so that the circumjacent air , is not that which makes the wood weigh upon the man. . though the whole man be heavier than so much water ; yet many parts of him are lighter ; and would , of themselves , swim in water , ( though , by their connexion with some heavier , they be made to sink ; like wood tyed to a piece of lead : ) now all these parts , at least , ought to feel pain , if the specifick gravity were the onely cause of indolency : but do not . . a man immersed in quick-silver , which is a heavier fluid , though he would thereby be boyed up , yet would he no more feel the incumbent weight , than a like weight of water . and , though the experiment cannot so conveniently be made in quick-silver as in water ; yet as to part it may be made , by thrusting the hand into quick-silver , which shall no more be pressed by it , than if thrust into an equivalent depth of water ; that is , about times as deep . and flyes , or other small animals , immersed in quick-silver , are not thereby pressed to death , but do safely emerge to the top. so that it is but a fansie to think , that onely the proportional or specifick lightness of the water , is the cause of that indolence , since liquids proportionably heavier , if not positively heavier , will be felt as little . . let us suppose an inverted syphon , ( fig. . ) filled from a to b with quick-silver ; from thence to c with water , so high as to ballance the quick-silver at a. if now oyl ( which is lighter than either ) be poured on a ; i ask , whether the quick-silver at a will not be thereby depressed , and that at b and c raised ? certainly it will. but why ? the oyl cannot ( by their principles ) gravitate on ab , because this is quick-silver : nor yet ( as they speak ) mediately upon bc , for even this is water , and therefore heavier than oyl : no , nor on the air above c ; for the oyl at da is already lower than it , and therefore cannot affect to possess its place . it should therefore , by their principles , not gravitate at all , since there is nothing below it lighter than it self , on which it should gravitate : yet gravitate ( we see ) it will , and thrust out of place that whole body abc ; notwithstanding ( if that be considerable ) the higher position of c , and its greater specifick heaviness . and all this while the animal in bc shall remain unhurt , notwithstanding there be not onely gravitatio ad pondus , but gravitatio ad motum too . so that the notion of non-gravitation on a fluid not specifically lighter than it self , is quite out of doors . and the truth is , supposing abc to be in equipoise , the superfusion of ad will equally depress a , whatever the liquor be , if the weight be equal . and ounce weight , will still be an ounce weight ; and an ounce weight will just so much depress the quick-silver , whether it be an ounce of wine , water , oyl , or quick-silver ; ( that is , just so much as to thrust half that weight , out of the leg af , fig. . into the leg fc ; ) without any regard had to the specifick gravity or levity of the liquor ad , which , as to this point , is of no consideration at all . and if the higher position of d above a be thought of moment ; the higher position of c above both must be so too . and there will be nothing steady to fix upon , but , that the positive weight of df being ( at least in proportion to the bigness of the pipe ) more than that of fc ; that will thrust this away , till they come to an equipoise . it 's true , that , if the specifick gravity of the liquor ad , were greater than that of the quick-silver in ab ; there would , upon another account , have been some difference : because then , the heavier liquor being upmost , it would not onely press upon , but press into , the body of the lighter ; and they would by little and little shift places ; ( as when water is poured upon wine , that will by little and little sink to the bottom , and this rise : ) because , by such descent , each particle thrusts up a lighter body than it self . but , if the upper be lighter ; though it press on the hevier , it cannot press into the heavier , without thrusting up a heavier body than it self . and this , i suppose , if they will consider their own notion , is that they mean , when they say , a lighter body doth not gravitate on a heavier . and if so much oyl were poured on a , as to thrust the quick-silver beyond f ; some of that oyl would pass by it , into the other leg , as high as c. and , in such cases as these , the specifick gravity or levity is considerable : but not as to the case in hand ; where an ounce of oyl poured on a , shall depress it just as much as an ounce of quick-silver would do ; and thrust up c just as high. beside this , ( of non-gravitation on a heavier body ; ) the same learned author hath two expedients for salving the indolence of a man under water , or his not feeling pain by the weight of it . the first is this : supposing a brick-work , as in fig. . but without mortar ; if some few bricks were taken out of the bottom , there would not hereupon sink a pillar of that base , but onely a kind of pyramid ; the rest being , in manner of an arch , mutually supported . and thence he supposeth , that those middle bricks did not bear the weight of a column , but onely of a pyramid . which pyramid if taken away , the rest would not gravitate upon that cavity . and in like manner he supposeth it must be , if , for bricks , were grains of wheat ; yea , of sand ; and , consequently , of lesser particles ; and , even those of water ; which he supposeth would thus support each other , without gravitating on those under them . but he proceeds upon several mistakes . first , he supposeth , that , because those middle bricks being taken away the rest do not fall ; therefore , when they were there , they bore nothing of that weight . which is just as if he should argue , because , when a beam ( in fig. . ) is supported by three posts , if the middle post be removed , it will not fall ; therefore , while it was there , it did bear nothing of the beams weight : or , because a table , ( in fig. . ) supported by five or six legs , will stand , though any one of them be taken away ; therefore that leg did bear nothing : and consequently , ( because that leg is any leg ) therefore none of them did bear any weight : whereas , while all were there , each did bear its part , and thereby ease the rest ; which , in the absence of one , must now bear the more . and if the whole space under it were filled up with such supports , ( or , which would be equivalent , an intire body of that breadth , ) each would bear ( without any considerable difference ) just so much as what is just over it . and such is the case of fluids . onely this i add , that if one of the legs should be too weak to bear its proportional part , yet if the rest be as much more than able to bear their ; that weak one will not break , being relieved by the rest . secondly , admitting that in brik-work it would so be ; yet it is onely upon this account , because those parts of the bricks which hang over , are coherent with the parts supported , and cannot fall without breaking the brick : but , if they were as easily separable part from part , as brick from brick , ( which is the case of fluids ; ) those parts would fall , as well as the middle bricks : and consequently , not a pyramid , but a column , or rather more . again , thirdly , whereas he argues , from bricks to grains of wheat , and from thence , to sands , the consequence will not hold . for the shorter his bricks are , the less will hang over in each layer . as if now , for instance , each brick lye two inches over ; if the bricks were but half so long , each would lye over but one inch ; and consequently ( supposing their thickness the same , ) the pyramid on that base would be twice as great ( because twice as tall ; ) and still , as the over-hangings decrease , that pyramid increaseth ; till at length , when those over-hangings come to nothing ( which is the case of fluids , ) the pyramid becomes a column , or even more than so . and if , in a heap of wheat , fig. . ( as here in a pile of bricks , ) he remove so much of the bottom ; he will find , that instead of a pyramid on that base , there will fall down more than a column ( part of an inverted pyramid : ) and the more such heaps approach to the nature of fluids ; the more will it be so . so that , by this argument ( if there were not another expedient , of which i shall speak by and by , ) the lower parts must bear , not less , but more , than the column incumbent on them . and , if he found it otherwise in a tube filled with moist calice-sand ; this was not , because that above did not gravitate ; but because it was so wedged in , that it could not fall . which , in perfect fluids , we are not to suppose . lastly , he doth , by this explication , destroy his own hypothesis . for he grants , in a pail of water ( for instance , ) that all the parts , as well upper as lower , do gravitate on the bottom , though not each on other : whereas , if those upper parts be so supported ( as in his brick-arch ) as not to gravitate on the cavity ; much less will they gravitate on the bottom , under that cavity . and if , as he supposeth , a great heap of wheat would not break an empty egg-shell ; it is not , because the wheat wants weight , or gravitation ; but because the grains are so intangled as not to fall right down , ( like as in a heap of bushes , one would bear up another , though all do gravitate : ) but in liquids it is otherwise ; which we suppose partible in every point . but however , this of the egg-shell happen to prove ; it serves not his hypothesis at all . for , the air in the egg-shell , being lighter than the wheat that lyes on it ; this ought to gravitate ( by his own principles , ) and to break the egg-shell . if , by arch-work , the egg-shell be defended ; this is not for want of gravitation ; but because that gravitation is surmounted by a greater strength . like as when a great weight hangs on a strong tack ; or a heavy scale , supported by as great a weight in the other , or by a support underneath ; and a thousand other the like accidents . his other expedient is , from the lateral pressure which he supposeth all fluids to have ; whereby he supposeth the perpendicular pressure to be abated . but here he proceeds upon a mistake also . for , though it be very true , that water will flow upon a declivity ; yet not as fluid , but as heavy . for we see a bowl runs down a hill , though not a fluid , but a solid , body . and a broad solid , lying on a narrow pillar , ( in fig. . ) hath in every part a lateral pressure as well as water ; and , if it be cut in the middest , will fall off on either side , as water would do . and , when it doth not ; the reason is not a want of propension , but because this lateral propension is checked or impeded by a greater strength of cohesion ; like as its perpendicular propension is checked by that greater strength of the pillar . and like as the pillar , if too weak , will break under the perpendicular weight ; so , if the strength of cohesion be less than its lateral propension , the solid will divide as a fluid would do . as when a solid breaks by its own weight , ( in fig. . ) on the contrary ; water in a pail ( or other vessel , ) though a fluid , hath its lateral propension restrained by the sides of the vessel ( as by a greater strength , ) but doth not lose it ; and , if the sides chance not to be strong enough , will break through ; doth at least endeavor it , though they be strong enough . so that , both in solids and fluids , each particle hath its lateral propension , as well as perpendicular ; though it be sometimes restrained , or over-powered ; there , by the cohesion of parts ; here , by the strength of the sides : but ( in both cases ) if those strengths be too weak , that propension prevails . now , as this lateral propension of fluids , is kept in by the sides of the vessel , as to the utmost parts of it ; so , as to the inner parts of it , they keep in each other . the lateral pressure of a , ( fig. . ) is sustained by that of b ; and this by that ; not as by greater , but as by equal strengths . for a cannot thrust away b , without thrusting up a body as heavy as it self ; nor b thrust away a. so that , the lateral pressure of the parts being mutually sustained each by other , and the perpendicular pressure by the parts under it ; hence it comes to pass , that those under-parts bear onely the pressure of a column , and no more ; ( which is the expedient that i intimated but now . ) and therefore , in the heap of wheat , but now mentioned , though , upon an aperture in the bottom , more fall down than such a pillar , ( because , when that is gone , the lateral pressure of the rest doth operate , ) yet , while that pillar was there , that part of the bottom did bear no more but it . but if these expedients of his do not serve ; what is the reason ( you will ask ) that the man under water , feels not the weight of it ? i would answer , first , that it is not agreed , that , at a great depth , a man shall feel no pain at all . and i hear , that mr. gratrix having contrived a way of taking breath , at a great depth under water , through long pipes reaching to the top of it ; yet found his breast there so compressed by the water , that he could not draw breath . but , in small depths of water , i do not deny but that a man may remain for some time without any considerable pain . the reason , i judge , is this ; because the man incompassed by a fluid , ( whether specifically heavier or lighter than himself , it makes no matter , ) is equally pressed on all sides ; and thereby suffers no luxation of parts ; and , consequently , no sense of pain . but upon the luxation or laceration of any part , especially a nervous part , pain ariseth . hence it is , that our flesh feels not the hardness of our bones , because so fitted thereunto as to suffer no luxation or laceration by it : but , if the bone be broken or dislocated , we shall then find it to hurt us ; and feel it hard and sharp . and though the body , by such compression , may be contracted into a less room , by reason of the air , blood , and other springy liquids ; yet these being all uniformly pressed , without any tearing of the nervous parts , he suffers nothing of pain from it . and hence it is , that the egg-shell , ( but now mentioned , ) though pressed by a body specifically heavier than it self , ( by which therefore , according to their principles , it ought to be crushed , ) receives no prejudice , because equally pressed on all sides : which it doth the more easily sustain by reason of its round form , in the nature of a continued arch. and we find , in experience , that a round glass , though but of equal thickness , will bear a much greater pressure from without , than from within ; and more than if it were flat-sided ; and more , if the pressure be of all sides , than if but in some onely . all which concur in the egg-shell so situated : but if pressed onely upon one side , a less pressure would break it . i add also , that though in perfect fluids there be no such arching ; yet in a heap of solids ( as that of wheat ) something there is of that nature ; and the more , as those grains be bigger , and conveniently shaped ; and may therefore help to bear the burden : like as or legs , in the table we mentioned , if strong enough , will supply the defect of one weak one ; which therefore is not broken , though not strong enough of it self to bear its part . but the more any such heap approacheth to the nature of a fluid , the less is there room for such arching ; and , in perfect fluids , none at all . hence it is also , that a spunge , though lighter than water , and flaccid also , will not yet ( though fastened to the bottom of a vessel ) be crushed together by the weight of the incumbent water ; because the water within its pores doth bear out the sides with as great a strength , as that without would press them in . and the like we see , when the lungs , taken out of animals , are immersed in water . and the same account serves , for the pressure of air on animals . the air within , pressing as strongly outward ( by its spring , ) as that without , presseth inward ; there is no hurt to the animal at all . and , contrary-wise , the pressure of the air into the mouth and throat , doth not break open his brest or belly , because ballanced with as great a pressure without . but if a hand or arm , be put into the air-pump , and the air about it pumped out , that there be a failure of the outward compression to ballance that within the arm ; the spring of that within it , will put the arm to a great torture , ( as divers of this society have found by experience . ) and many animals , by that means , have been killed within the same pneumatick engine , in a much shorter time , than would have been for want of respiration onely . the like is seen in the breaking of glass bubbles hermetically sealed , and of lambs bladders , in the same pneumatick engine , upon the subtraction of the ambient air ; as also the boiling of warm water , and the strange expansion of blood into bubbles , upon such subtraction of air ; and many the like experiments , made by mr. boyle ( an honourable member of this society ) in that pneumatick engine of his invention . but while i name these , i do anticipate what i am next to handle ; which is the compression of springy bodies . we have been hitherto discoursing of such fluids principally as water is supposed to be ; that is , fluids uncapable of compression , because not elastical or springy . but springy fluids , such as we suppose the air to be , may by an incumbent weight , not onely suffer a trusion ( as water may ) into another place , ( as from a to b and e , in an open pipe , in fig. : ) but a compression , into a less place . as for instance , if the pipe be close stopped at c , ( or hermetically sealed , ) so as ab be water , and bc air , or other springy fluid ; a superfusion or addition of the weight ad ( whether fluid or solid , ) will raise b to e , and contract the air bc into the space ec ; that is , so much as till the spring in cb , ( which was a strength equivalent to the pressure of ab , ) becomes ( by this contraction ) equivalent to the pressure of db. and if more yet be superfused on d , ce will be yet more contracted , and so onwards ; the strength of the spring being still made equivalent to the pressure of the weight . for , while the spring cb is too weak ; the weight ( being a greater strength ) will thrust it closer : and , if ce be too strong , it will ( as a greater strength ) thrust away that pressure : and can never rest , but when the strength of the spring is just equivalent to the pressure . so in solids : if ( for instance ) a room or vessel be filled with wool as high as bb , ( fig. . ) and more wool or other weight ( whether heavier or lighter than wool ) be laid on , as to aa ; the wool shall be depressed to le ; and more yet , if more weight be laid on . and in like manner , if bcb be air , and this pressed , either by the incumbent air ab ( supposing air to be heavy , ) or by a solid weight or force , so close on all sides , as that the air cannot pass by or through it . and , this being granted ; the torricellian experiment ( with others of the same nature ) is , confessedly , solved by the pressure of the air ; which was anciently thought to be by a fuga vacui . for , if the air be heavy , it must gravitate ; that is , endeavour a descent ( as other heavy bodies do , ) and actually effect it , if not opposed by at least as great a strength . and the spring of the air ( allowing it to have a spring ) must always be of such a texture , as is equivalent to the weight or force which it bears . now , as to the weight of air , or its positive gravity , the peripatetick philosophy doth not acknowledge it ; but takes it to be positively light , and consequently to endeavour an ascent . and some others say the same , not onely as to air , but as to all heavy bodies . and whereas we suppose in them a positive gravity ; and that what we call levity is but comparatively so , being onely gravity in a less degree ; they take levity to be positive , and gravity to be but a less degree of levity ; and , consequently , those heavy bodies , not to affect a descent , but to be thrust down by bodies more light , which more strongly affect a higher place . but against these ( the one and the other ) i apprehend ( as to philosophy ) these inconveniences ; which , to me , seem cogent arguments . if this motion up-ward be natural ; it must be either an aversness from the center , as the terminus à quo ; or a propension to some other place , as the terminus ad quem . if they say the former ; it is true , that then b ought to move from c , in perpendicular lines , as cba , ( fig. ; ) and the phaenomenon doth not contradict it . but if the first intendmnent of nature be , not to be here ; without any positive tendency , where to be ; it seems much more intelligible , that somewhat should thrust it thence , ( by somewhat more forcibly pressing between , ) than that it should fly thence , without affectation of any other place . but if they say , ( as seems more rational , if levity be the positive principle , ) that it is an affectation of some higher place , suppose a : while b is just between c and a , the motion ( 't is true ) would be in the perpendicular cba , ( as the streightest way thither : ) but if it were any where else , as at d ; then its motion to a would not be in dce the perpendicular , but in da an oblique line . which is contrary to all experience : for the same light body , where-ever it be , moves upward in a perpendicular ; as well as a heavy body , in a perpendicular downward . and if , to avoid this , they would say , that it moves not to a certain place , as a or e , determinately ; but to that place , whatever it be , that is just over it : i say , this is not properly the moving to a place , ( if it be indifferent whether to a or to e ; ) but rather a moving from a place ; that is , to be as far from c as it can : which is the former branch of the supposition , and against which we did before urge the former inconvenience . which makes it not likely , that there is any such thing as positive lightness at all ; since it will be hard to assign , what shall be the terminus ad quem , which such a mover aims at . but waving this argument from philosophy at large ; i shall argue from experiment , ( as to the air , ) thus : suppose we air in the bladder aa , ( fig. . ) of the same tensure with the external air ; and therefore such as will not ( as they speak ) gravitate , or ( as i would rather say ) praegravitate thereon ; nor yet praelevitate ; ( being of the same specifical gravity or levity with it : ) if this be compressed into a less room , as bb ; it will then retain the same quantity of gravity or levity as before , ( since all that air is still here , with all its positive quality : ) but ( because now within less dimensions ) it will be gradually , or ( as now the language is ) specifically , more than before , heavier or lighter , according as that positive quality was gravity or levity . ( for , as the same quantity of heat , in lesser space , makes the subject intensively hotter ; so the same quantity of heaviness , in a less room , makes it intensively heavier ; and , of lightness , lighter . ) but experience testifies ( as is confessed ) that compressed air is intensively heavier , or ( as we now speak ) specifically heavier , ( and on the ballance is found so to be ; ) not lighter , than before . therefore its positive quality was heaviness , not lightness . the positive gravity of the air being thus evinced ; and , consequently , that the air ascends , onely because it is thrust up by bodies more heavy ; ( like as water riseth upon the casting in of earth , or other heavier bodies ; ) the torricellian experiment , with other the like phaenomena , are easily solved from statical principles , without having recourse to a fuga vacui . for , admitting ( as before ) that ( in a vessel with a nose ; or a syphon inverted , fig. , . ) the fluid at a , by sinking it self , will raise that at b , to the level le ; then , in case the nose at b be not so high , the liquor ( if not otherwise stopped ) must needs run over . and , if any should say , the reason hereof is , because the air at b flies away ( by its levity ) and the water follows to avoid a vacuity ; he would hardly be assented to by those , who see a visible weight or force at a , to over-press it , and thrust it out . and , for the same reason , if the nose or pipe , before it comes to the height of e , be recurvate , ( fig. , . ) and turned down to o ; that which would have run over at b ; will now run out at o ; being thrust up to b , by the weight of a , and falling down from thence , by its own weight . but in case a be lower than b , fig. . ( and the fluid uniformly heavy ; ) a will not be able to drive it up to b , much less make it there run over , or turn about to o : but , contrary-wise , if it were full to b , this would praeponderate , and raise that at a. yet , if ac were a heavier fluid , suppose quick-silver ; & cb a lighter , as wine or water ; the effect would follow as before ; till the greater height of cb , do countervail the greater heaviness of ac . and , contrary-wise , if ac be specifically lighter than cb , ( fig. . ) suppose that water , and this quick-silver ; then must that be in such proportion higher than this , or else it will not rise to b , nor run out at o. but , if ac be higher than in such proportion ; the effect will follow , from the praegravitation of a , without having recourse to a fuga vacui . and thus far the ancients would agree with us . for they never flye to a fuga vacui , so long as there is visible weight or force to thrust up the fluid . but that which gave occasion to introduce this notion of fuga vacui , were but these two experiments , ( and such as are reducible thereunto ; ) wherein , for want of a force to raise liquids by way of trusion , they had recourse to this of traction , ne detur vacuum . the first that of suction , in pumps , syringes , and other the like occasions . the other is that of a syphon , whereby liquors are carried over considerable heights above their level . for if the nose of a syringe be immersed in water , as at b , ( fig. . ) and the handle or embolus be drawn back ; the water or other fluid will follow it , from b into d : which being contrary to the nature of a heavy body , and no other force appearing to thrust it up ; it was imagined , that nature abhorred a vacuum , and this made the liquor rise contrary to its particular propension . to which fuga vacui ( as it was wont to be called , ) linus of late ( and some others after him ) have given the name funiculus . and the like is to be said of all sorts of pumps , and other the like engines , which draw water by way of suction . and as to the syphon ; if the end c be immersed in water , or other liquor , ( fig. . ) though b , the top of the syphon , be much higher than a , the surface of the liquor ; yet , if o be lower than a , though it will not of it self begin to run ; yet , if by suction or otherwise , it be set a running , this current will continue , till either a be sunk so low as to let in air at c , or be lower than the outward orifice o. the reason whereof , say they , ( since there appears not any force to thrust it up , ) must needs be this ; bo flowing out by its own weight , if cb did not follow it ( contrary to the propension of its own gravity , ) a vacuum must needs ensue ; which therefore , they suppose , nature doth abhor . for answer , i say , first , there being no other foundation in nature to prove this abhorrence , but onely these experiments ; and this not otherwise known , but being onely invented as an expedient to serve a turn : if we can otherwise solve the phaenomenon , and shew a force which they did not think of ; there will be no need of this expedient at all . and this abhorrence must be either gratis dictum , without any cogent proof ; or some other evidence must be shewed for it , than those who did introduce it were aware of . for all the subsidiary proofs of late invented , were not the grounds of introducing the opinion . and therefore , without disputing , whether nature can or cannot admit a vacuum ; i shall onely shew , that there is no need of that notion as to this business . next ; that this fuga vacui is not the cause of water thus rising in a pump or syphon , i thus argue . for , if so , it ought to hold to any height whatever . a pump ( for instance ) must draw water an hundred foot high ; and a syphon convey water over the highest hills or towers . for , the argument equally holds , whether the height of b , be two foot , or two hundred foot ; if bo flow out , and cb not follow , a vacuum must insue equally in either case . and the consequence of this argument is so clear , that , in confidence thereof , the ancients did not doubt but that it would be so . none ( that we know of , ) till galilaeo's time , having ever questioned it ; or assigned any determinate height beyond which a pump would not draw water , or over which a syphon would not convey it . and it was a surprising discovery , and wholly unexpected , when ( about the end of the last century ) it was first found out by experience , that water could not thus be drawn higher than about foot. i say , about foot ( not just so much ) because that alters with the temperature of the air. when the air is very light , it will not much exceed foot ; when very heavy , it may reach foot. which experiment alone did evidently evince , that the supposed fuga vacui , was not of an infinite , but of a determinate , strength . which put galilaeo upon the inquiry , whether it were not from some other cause than fuga vacui , that it would be drawn so high , but not higher . and he happily lighted on this hypothesis , of the counter-gravitation of the incumbent air. the same hath been since improved by torricellio ( and others after him , ) who rationally argued , that if such counter-gravitation of the air , would countervail the weight of foot of water ; it ought in lighter liquors countervail a greater height ; and a less height in heavier . and found , upon experiment , that so it was : ( if some little difference chance to be sometime discovered ; it is to be accounted for , from some different constitution of the air about us , or other little accidents , too many to be here recounted : ) and particularly , that , as water would be so raised about foot ; so quicksilver , to the height of about inches and no more : ( i mean , , or , as the airs temperature doth vary . ) which agrees with the proportion of the specifick weight of those liquids . ( quick-silver being near upon times as heavy as water . ) and , from him , the torricellian experiment takes its name . the experiment is thus administred , ( in fig. . ) a glass-pipe closed at the bottom , being filled with quick-silver , and then inverted ; the orifice being stopped ( with the finger or otherwise ) till it be immersed in a vessel of stagnant quick-silver , and then opened ; if the height of the pipe ( above the stagnant quick-silver ) be not more than inches , or thereabouts , it will remain full . the cause hereof , say they , is , ne detur vacuum : for if the quick-silver should sink , there being no way for the air to enter , there would ensue a vacuum , which nature abhors . the cause , say we , is , because the weight of the incumbent air on a , ( which we have already proved to be heavy , ) is equivalent to the weight of inches of quick-silver : which therefore , being defended by the closed glass ( which we suppose otherwise to be held firm , ) from any other pressure than its own weight , is by that counter-pressure sustained . but further : if the height of the pipe above the stagnant quick-silver be more than about inches ; that in the pipe will sink to that height , as at e , leaving space above it in the glass , void of quick-silver : ( but , whether filled by any other imperceptible fluid , we dispute not . ) the reason why it so sinks , our ancestors have not assigned ; because they were not at all aware of this phaenomenon ; but thought , that ( ne detur vacuum ) it would remain full , whatever the height of the tube were . some moderns ( with des cartes ) that they might avoid a vacuum , do imagine , that a materia subtilis ( of which no sense can make any dicovery ) piercing the pores of the glass , supplies that place . but , if it will so supply the place above e , and give the quick-silver leave to sink so low ; why it might not as well come-in to relieve the rest , and so give it leave to sink to a , i do not find . others ( with linus ) imagine , that the weight of inches of quick-silver doth stretch some part of its upper surface into a subtile matter , very thin , yet so as to fill that seemingly void space ; but , because a less weight will not serve so to stretch it , it falls no lower ; which stretched matter , like a funiculus , holds up the rest , ne detur vacuum . but , why this weight should stretch some very small part of it , so prodigiously thin , and not stretch the rest at all , rather than give some moderate tensure to the whole ; they do not ( that i remember ) assign any reason . others , suppose this funiculus to be made , not by stretching the upper part of the quick-silver ; but by squeezing out the more subtil parts from the whole body of it , which like a vapour fills that seemingly void space ; but that less than such a weight would not so squeeze it , and therefore it falls no lower . but , why it should so fall out , that all liquors whatever , of never so different texture , should by the same weight be thus dissolvable ; and not rather some require a greater , some a lesser weight thus to resolve or squeeze them ; they assign no reason : yet we find so it is , since that the lighter the liquor is , the greater height must be allowed , and in such proportion greater , to make up an equivalent weight . but the cause is , say we , ( and it seems the most simple and unforced account , ) because the counter-pressure of the air , being equivalent to that of about inches , so much it is able to sustain but no more ; and just so much weight it will sustain whatever the liquor be , whether specifically lighter or heavier , and whether of a more firm or a looser texture ; and therefore to such a height it sinks , but no lower . and had the ancients been aware of what we find ; that the air hath a positive gravity ; and , consequently , though it be but small in proportion to that of other bodies , yet a great height of air may countervail a lesser height of a heavier liquor ; ( like as we see that a greater height of water will countervail a lesser height of quick-silver : ) they would not , i presume , have troubled themselves with a fuga vacui ; but said roundly , that the weight of the air at its full height , is equivalent to that of water at the height of about foot , and of quick-silver , at about , inches , and proportionably of other fluids . and consequently , when ( in the pump or syringe ) d by the embolus or sucker is defended from the airs pressure , but a exposed to it ( in fig. . ) this pressure on a , will raise , over b , so much weight of water , quick-silver , or other fluid , as is equivalent to that pressure . in the same manner as ( if a and e were equally exposed to the airs pressure ) a quantity of oyl , poured on a , would have raised a weight of water or quick-silver equivalent thereunto . the like account we give of the syphon . the pressure on a , ( in fig. . ) will raise the fluid to the height of b , if not greater than what is before described ; and from thence to o , it falls by its own weight : yet so , that if o were higher than a , the airs pressure at o , would thrust up o to b ( supposing the pipe not so big , as that the air could conveniently pass by the liquor into the pipe , ) and it would fall down to a by its own weight . for now bo would less gravitate than ba ; while yet the airs pressure would be much the same on both . there is yet a considerable objection to be removed , viz. that air in a closed vessel , though of no great height , pressing on a the surface of the stagnant quick-silver , ( fig. . ) will sustain as high a pillar thereof in a closed tube , suppose ae , as if a were exposed to the open air : whereas yet the weight of ad within the vessel , ( defended by the vessel from the pressure of the incumbent air , ) cannot be of equal weight as if it had the whole height of the atmosphere . but the reason of this is , from the airs spring ; which is always equivalent to the pressure lying upon it : and consequently , the spring of the air in its ordinary constitution with us , must be equivalent to the weight of the incumbent air. ( for , if it were less , the air incumbent would yet press it closer ; if it were more , the spring would relax it self , by thrusting away what presseth it . ) which being so ; the air included with such a spring , must therefore press with as great a strength as is equivalent to such a weight . like as , in other springs , if acb ( in fig. . ) be pressed by the weight d to such a tensure as to bear it ; and then , this spring so remaining , the weight were taken away , and our hand put in the place of it ; it would press as hard against the hand , as before it did to sustain the weight ; that is , with a force equal to that of the weight it sustained : and if , thus bowed , it were put in a vessel , ( in fig. . ) it would , with just the same force , press against the sides of it . and just so it is in the present case ; where the air so included doth press by its spring , just with the same force as was that of the incumbent air which gave it this tensure . it is yet the more evident , because if ( by the air-pump ) part of this air be pumped out , and thereby the rest less compressed ; the quick-silver in the tube , ( in fig. . ) will sink from e to a lower station , as to f or g ; and so lower and lower , as more and more air is pumped out , and the spring thereby relaxed : that is , as the spring grows weaker , so it is less able to support the weight . and this quite destroys the evasions but now mentioned ; that the seeming void space is filled by a thin substance , which can by the weight of inches of quick-silver , or foot of water , but not by less , be stretched to that fineness ; and that therefore it will sink to that height , but not lower . for , by this last experiment , when the air is included with its ordinary tensure , it sustains the quick-silver at the height of inches ; as if less than that weight were too little to stretch the quick-silver into that supposed fine substance : but , when that air , by pumping , is weakned ; it will sink to , , , yea less than inch of height ; as if now less than the weight of inch were enough so to stretch it , as less than inches would not do before . yet is no alteration , all this while , made in the texture of the quick-silver ; but in the tensure of the air onely . 't is therefore from this different tensure or spring of the air , not from any difference in the quick-silver , that it stands sometime at a higher , sometime at a lower station . and what hath been thus said of this torricellian experiment , is easily applicable to others of like nature . and it is confessed , that , as the notion of fuga vacui , or that of the airs pressure , doth stand or fall as to this experiment ; so must it do as to the others also . i content my self therefore , to have shewed it in this ; without expatiating to other particulars . finis . a continuation of new experiments physico-mechanical, touching the spring and weight of the air and their effects. the i. part whereto is annext a short discourse of the atmospheres of consistent bodies / written by way of letter to the right honourable the lord clifford and dungarvan by the honourable robert boyle ... boyle, robert, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing b estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) a continuation of new experiments physico-mechanical, touching the spring and weight of the air and their effects. the i. part whereto is annext a short discourse of the atmospheres of consistent bodies / written by way of letter to the right honourable the lord clifford and dungarvan by the honourable robert boyle ... boyle, robert, - . 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marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng air. air-pump. physics -- experiments. - tcp assigned for keying and markup - aptara keyed and coded from proquest page images - derek lee sampled and proofread - derek lee text and markup reviewed and edited - pfs batch review (qc) and xml conversion a continvation of nevv experiments physico-mechanical , touching the spring and vveight of the air , and their effects . the i. part . written by way of letter , to the right honourable the lord clifford and dungarvan . vvhereto is annext a short discourse of the atmospheres of consistent bodies . by the honourable robert boyle , fellow of the royal society . oxford , printed by henry hall printer to the university , for richard davis , in the year . the preface . having at the beginning of the treatise , whereof this is a continuation , acquainted my readers with several things that belong in common as well to the following experiments , as to those there publish'd ; it will not be necessary for me to trouble the reader with a repetition of what he may have met with there already , nor to acquaint him in this address with any other particulars then those that concern the experiments i am now about to present him . i doubt not but it will be remembred by some , that i seem'd in the above mentioned book to have promis'd a second part of it , or a large appendix to it : but intimations of that kind do many times respect onely the thing it self , leaving the giver of them free in point of time : and i wanted not sufficient inducements to delay a while to perform my promise , if i made any . i had indeed , partly before the book already referr'd to came from the press , and partly sometime after , made divers other tryals in order to a supplement of it : but being oblig'd to make some journeys and removes , which allowed me no opportunity to prosecute the experiments , i had made no very great progres in my design , before the convening of an illustrious assembly of virtuosi , which has since made it self sufficiently known under the title of the royal society . and having then thought fit to make a present , to persons so like to imploy it well , of the great engine , i had till then made use of in the physico-mechanical experiments about the air ; and being unable afterwards to procure another so good , i applied my studies to other subjects , and gave over for a great while the care of making more experiments of that kind : and the rather , because that finding by the very favourable reception those i had publish'd had met with among the curious in several parts of europe , that they were like to be considered and perused ; i thought i might safely leave the prosecution of them to others , who would probably come more fresh and untired to such an exercise of their curiosity . but observing , that the great difficulties men met with in making an engine , that vvould exhaust and keep out a body so subtle as the air , and so ponderous as the atmosphere , ( besides perhaps some other impediments ) vvere such , that in five or six year i could hear but of one or two engines that vvere brought to be fit to work , and of but one or two nevv experiments , that had been added by the ingenious owners of them ; i began to listen to the perswasions of those that suggested , that unlesse i resum'd this work my self , there would scarce be much done in it . and therefore having ( by the help of other work-men then those i had unsuccesfully imploy'd before ) procured a new engine lesse than the other , and differing in some circumstances from it , we did ( though not without trouble enough ) bring it to work as well as the other , and , as to some purposes , better . and having once got this , i made hast to try with it those experiments , that belonged to the design'd continuation , and do now make up this book . i hope , that to such readers as the following papers are principally intended for , i shall not need to make an apology either for the plainenesse of my style , ( wherein i aim'd at perspicuity , not eloquence , ) or for my not having adorn'd or stufft this treatise with authorities or sentences of classick authors , which i had neither the leisure to seek , nor thought i had any great need to imploy , though it had been far more easie then perhaps it would have proved , to borrow from them things that would have been very proper to a treatise where my main design was , to make out by practicable experiments divers things among other that have not hitherto been advantaged by that way of probation , nor perchance thought very capable of it ; so that i shall have obtained a great part of what i aim'd at , if i have shewn , that those very phaenomena , which the school-philosophers , and their party urge , and sometimes triumph in , as clear proofs of natures abhorrency of a vacuum , may be not onely explicated , but actually exhibited , some by the gravity , and some also by the bare spring of the air. which latter i now mention as a distinct thing from the other , not that i think it is actually separated in these tryals , ( since the weight of the upper parts of the air does , if i may so speak , bend the springs of the lower , ) but because that having in the already published experiments , and even in some of these , manifested the efficacy of the airs gravitation on bodies , i thought fit to make it my task in many of these , to shew , that most of the same things that are done by the pressure of all the superincumbent atmosphere acting as a vveight , may be likewise performed by the pressure of a small portion of air , included indeed ( but without any new compression ) acting as a spring . the present first part of our continuation might i confesse have been not inconveniently divided into two parts . for first it contains some experiments that are already related in the printed book , though they be here so repeated , as to be confirmed , illustrated , or improved , by being reiterated either with better instruments , or with better successe than when they were made in my large receiver , which holding ( if i misremember not ) about eight gallons , could not easily be so well exhausted as those small receivers i often since imployed . and secondly , the other and far more numerous sort of experiments , related in this first part , are new and superadded . and yet i forbear to assign each of these two sorts a place by it self , because i could not conveniently set down my tryals otherwise then as they came to hand among my notes ; and i considered , that in divers places the new ones and the old ones being mentioned together , might serve by their neighbourhood to illustrate or confirm each other . and however at another edition of our continuation it will be a very easie task , if it appear to be a requisite one , to give the improvements of the former experiments , and the superadded new ones , distinct titles and places . as for the mechanical contrivances i imployed in making the following experiments , though most of them have had the good fortune to meet with an approbation , and some of them with more than that , from no mean virtuosi and mathematicians ; yet as i expect that critical readers will judg , that in some experiments more artificial instruments might have been made use of , so i hope that they will not look upon those i was reduced to imploy , as alwayes the best that ever i could have directed , since it sufficiently appears by diverse passages of the following experiments , that they were not made at london , but in places where the want of a glass-house and other acaccommodations reduced me to make my tryals not after the best manner i could devise , but in the best way i could then and there put in practice . and let me add on this occasion to what i have elsewhere said to the like purpose , that t is both a great discouragement to many ingenious men , and no small hinderance to the advancement of natural philosophy , that some nice criticks are so censorious in exacting from attempters the very best contrivances , and many that would be attempters stand too much in awe of such mens judgments ; for though in very nice experiments the exactnesse of instruments is not onely desireable and useful , but in some cases necessary ; yet in many others , where the production of a new phaenomenon is the thing aimed at , they are to be looked upon as benefactors to the history of nature , that performe the substantial part of a discovery , though they do it not by the most easie and compendious wayes deviseable , or attain not to the utmost preciseness that might be wished , and is possible . for such performances , notwithstanding their being short of perfection , make discoveries to the world of new and useful things ; which though others , that are more lucky at contrivances , and have better accommodations , may compasse by more compendious wayes , or with greater precisenesse ; yet still the world is beholding to the first discovery for the improvements of it , as we are to archimedes for the first devising a way , to find by weighing bodies in water , how much gold or how much silver a mixture of those metals does contain , though ( if historians have not injured that great man in the relation ) he went a more laborious and lesse accurate way to work than modern hydrostatians , who ( as i elsewhere shew ) may perform the same thing by a far better way , which yet probably we should not have thought of , if that attributed to archimedes had not preceded , and afforded us a fundamental notion . and that the not being so dexterous at contriving the wayes to effect a thing , is no sure argument that a man has not a true and solid knowledge of it , we may easily learn from euclid , vvhom our geometricians generally and justly acknowledge to be their master , and to have enriched the world with many useful truths , and solidly demonstrated all his propositions , though divers of his modern commentators have found out more compendious wayes for effecting several of his problems , as vvell as of demonstrating divers of his theorems , especially since the excellent invention of specious algebra , by whose help that accurate mathematician dr. wallis has , besides other specimens upon intricate propositions , clearly demonstrated the ten first and for the most part perplexing theorems of the second element , in litle more than as few lines . in summe , in experiments that are very nice , accurate contrivances and instruments are industriously to be sought , and highly to be valued , and even in such other experiments as are frequently to be reiterated the most commodious and easie ways of performing them are very desireable , but those practical compendiums , though very welcome to them that would repeat tryals , are not so important to the generality of readers , as being but useful to save pains , not necessary to discover truths ; to vvhich men may oftentimes do good service , without any peculiar gift at mechanical contrivances , since in most cases they may be lookt upon as promoters of natural philosophy , who devise experiments fit to discover a new truth if the attempt succeeds , and propose wayes of bringing it to trial , which though perhaps not the most skilful or expeditious , are yet sufficient and practicable , the increase of physical knowledg being the product of the things themselves that are discovered , whatever were the instruments men imploied about making the discoveries . as for the cuts , i endeavoured to make their relations , and descriptions of most of the experiments , so full and plain , as to need as few schemes as might be to illustrate them : but though i hope , that they who either were verst in such kind of studies , or have any peculiar facility of imagining , would well enough conceive my meaning onely by words ; yet lest my own accustomance to devise such trials , and to see these made , should make me think them more easily intelligible than most readers will find them , i advised with a learned friend or two , fit to be consulted on such an occasion , what experiments were requisite to be illustrated with diagrams , and to such i took care they should be annexed . onely i forbore to adde to the figure of each instrument alphabetical explications of its parts , as judging that troublesome work lesse easie for me , than it would be for such readers as this tract is designed for , to understand what is delivered by the help of a litle attention in conferring the schemes of the instruments with the verbal accounts of the experiments they relate to . but there is one particular about the cuts may require both to be given notice of and excused : which is , that having occasion to alter the method of my experiments , when i began to foresee that i should be obliged to reserve divers things for another opportunity ; and being my self absent from the graver for a good part of the time he was at work , some of the cuts were misplaced , and not graven in the plates , in which , according to the present series of experiments , they might most properly have been put . but perhaps i may ( for i am not sure of it ) more need the readers pardon for ( unknowingly ) troubling him in this continuation with some passages , that he may have already met with in the book it refers to : which though i had not read over for some years before , i chanced not to have at hand , when divers of the following papers were written ; and though afterwards i recovered it , yet the indisposition of my eyes made me think it unfit rather to tire them by reading over the whole book , than to trust to the readers good nature ( in case i should need it ) for the pardon of a few unintended repetitions . i doubt not , many readers will be inquisitive to know , why this treatise is stiled the first part of a continuation : to give these some account of the title , i must put them in mind , that in the already published experiments i intimated , that two sorts of tryals might be made by the help of our engine : the one , such as needed but a short absence of the air , and the other such as required that the air should not onely be withdrawn for a vvhile , but kept out for a considerable time , from the bodies vvhereupon the trial is made . of the former sort of experiments are these this present book does ( as vvell as that heretofore published did ) consist of . and though i have been so much called upon , and troubled for certain writings , whereof i had made such mention in those that past the presse , as some readers interpreted to be an engagement , that it made me think fit , when i satisfied their demands , to be thence forward very shy of making the publick any promise ; yet i was induced not to alter the title of this treatise , partly because it may intimate to the curious , that there are yet a great many things to be performed by our engine , besides the productions of it i have hitherto presented them , and partly because , though i still persist in my former aversnesse to make promises to the world ; yet t is very possible , that if god grant me life and health , i may in due time present my friends with what may serve for a second part of our continuation , consisting of experiments that require a longer absence of the air from the bodies to be wrought upon ; and i shall think , if this first part prove not unacceptable to the curious , that the latter will be not unwelcome to them , as being designed to consist of sets of experiments , which by their being most of them new , and some of them odd enough , may perchance afford some not despicable hints to the speculative . but the very nature of these experiments , requiring that some of them should be long in making , my friends could not reasonably expect a quick dispatch of a work of this kind , though i should not meet for the future with such intervening impediments , as have hitherto disturbed it , ( as want of instruments , of health , of leisure , and of the liberty , which is so requisite in this case , of staying long enough in one place : ) notwithstanding all which difficulties i have by snatches been able through god's blessing to make forty or fifty of designed tryals , being such as require the least of time to be performed in , though i now think not fit to mention any of them , as well for other reasons , as because though they be made by the help of our engine , yet they require a peculiar apparatus of instruments , very differing from those we have hitherto mentioned , and not to be intelligibly described without many words and divers figures . in the mean time , lest the industrious should be discouraged by a surmise , that there is nothing left for them to do by the help of our engine , at least as to the first sort of experiments , i shall inform them , that i had thoughts to have added divers others of that kind to these that now come forth , and particularly two clusters of pneumatical trials , the one about respiration , and the other about fire and flame ; but several of my notes and observations being at present out of the way , my having neither health nor leisure to repair these inconveniences , and prosecute tryals of that sort with any assiduity , makes me chuse rather to reserve them for an appendix , than to make those that now come abroad stay for them . which will not ( i presume ) be the more disliked , because by taking this course i may , in delivering of the phaenomena of nature , imitate nature her self , of whom t is the roman philosophers saying , rerum natura sacra sua non simul tradit . some advertisements touching the engine it self . though the engine already published , and that which i imployed in the following tryals , have the same uses , & agree both in the ground and the main part of their construction , yet they differ in some particulars fit to be taken notice of : for after i had presented the great engine i formerly made use of to the royal society , partly the difficulty of procuring such another of that size and make , and partly the desire of making some improvements invited me to make some alterations in the structure ; some of them suggested by others , ( especially by the ingenious m r hook , ) and some of them that i added my self , as finding that without them i could not do my work . wherefore it will not be amiss to point at the chief differences between the former and the latter engine , and to intimate some of the conveniences and inconveniences that attend them . as for the construction of the second engine it self , since t is presumed , that the readers of this book have already perused that of which this is a continuation , and understood the contrivance of the instrument that belongs to it , it was presumed sufficient to exhibit in the first plate the delineation of the entire engine ready to be set at work ; and in the second , the figures of the several metalline parts that compose it , before they are set together . for though these have not verbal and alphabetical explications annexed to them , yet the sight of them may suffice to make those that have an imagination fitted to conceive mechanical contrivances , and are acquainted with the former engine , comprehend the structure of this ; which , alphabetical explications would scarce make such readers do , as are not so qualified : onely two things there are , which being of some difficulty , as well as of importance to be conceived , i shall here particularly tak notice of . the first of which is , that in regard the sucker is to be alwayes under water , and the perforation p q , that passes perpendicularly quite through it , and serves together with the stick r s for a valve , is to be stopt at the bottom of the cylinder , as at n o , when t is full of water , t was requisite to make the stick r p of a considerable length , as two or three foot : the other and chief thing is that in the second plate , the pipe ab , whose end b bends upward , is made to lie in a gruve or gutter purposely made in the flat wooden board c d e f , on which the receivers are to rest ; which square board i caused to be overlaid with very good cement , on which i took care to apply a strong plate of iron , of the bigness and shape of the board , leaving onely a small hole for the erected part of the pipe to come out at , which i added , not onely to keep the wooden board the better from warping , but because i knew ( what will perhaps be thought strange ) that the pressure of the atmosphere on one side of the board , when there is no pressure or but very litle on the other side , will enable many aerial particles to strain through the very wood , though of a good thickness , and imbued with oyl to choak the pores ; to this iron-plate we sometimes fit a lip turning up about it , to hinder the water that on some occasions will come from the receiver from falling on the room ; ( and to add that upon the by ) though the stop-cock g h i k , that belongs to the hitherto mentioned pipe , may be inserted at i. into the barrel or cylinder l m n o by the help of soder , yet we chose as a much better way to have the branch i. of the stop-cock made like a screw , which being once firmly screwed in to the barrel , is not apt to be broken off , and may be more easily mended if any thing happen to be out of order , which the engine is the most liable to be in or about the pipe , partly because it may fall out , ( though but very rarely if due care be but taken , ) that the air will insinuate it self between the wooden board and the iron-plate , and so get up ( where the pipe bends upwards ) into the cavity of the receiver , and partly because the pipe being for a just reason made but slender , and the part of it that looks upwards very short , it happens not very unfrequently , that when we imploy receivers with narrow orifices , where the cement must lie close to the opening of the pipe , it happens , i say , that the cement , especially if it be much softned by heat , is suckt ( as they speak ) into the pipe , and so choaks it up ; or else that some part of the body included in the receiver is drawn to the orifice of the pipe , and lying upon it as a cover hinders the free passage of the air into the barrel , against which inconvenience , to add that upon the by , we use amongst other expedients to place just about the orifice of the pipe a small cover of tin , like that of a litle box , which covers it at the top to hinder any thing from lying immediately upon the pipe , and has a small opening or two in the side , to give the air of the receiver free access to the pipe. the square and hollow wooden part of this engine , discernable in the first plate , is so made , that it may contain not onely the cylinder , but so much water , as will alwaies keep the cylinder quite cover'd with that liquor ; by which means the sucker , lying & playing alwaies under water , is kept still turgid and plump , and the water being ready at hand to fill up any litle interval or chink , that may happen to be between the sucker and the inside of the barrel , does together with the newly mentioned plumpness of the sucker very much conduce to the exact keeping out of the air. but this advantage is not without some inconvenience , for divers times , if great care be not taken in turning the stop-cock , the water will be impell'd into the receiver , and much prejudice sundry experiments , when the included bodies are such that may be spoiled or impaired ( at least for the present ) by that liquor . the smalness of our cylinder is a convenience in regard of the facility it affords to make and dispatch those many experiments that may be performed in small receivers , though it make those more troublesome and tedious , that require the exhaustion of large and capacious ones . the flat plate ( mentioned a litle above ) has this great conveniency in many experiments , that the receiver needs no stop-cock of its own ; for such a vessel being made all of an entire piece of glass , and whelmed on upon the plate well covered with cement , can better keep out the air , than if there were a stop-cock , at which the air does but too frequently get in ; but besides that in divers experiments such receivers do usually require to be wide mouthed , whereby a greater compass is to be fenced against the ingress of the air , several experiments cannot so conveniently be tryed in this sort of receivers . but because , that though this second form of our engine hath as to several purposes its peculiar conveniences and advantages , yet some virtuosi may be furnished with the other already , and some may conceive it the more clearly of the two , or may judg it preferable for their particular designs ; i shall here intimate , that for most of the experiments , if not all , that follow in this treatise , they may make use of , or at least make a shift with the first engine , with a very few alterations ; whereof the chief is to be this , that to the upper part of the great cylinder , on the side opposite to the iron-rack , there is to be fastned such a square board , and suitable iron-plate , as is used in the second engine , betwixt which board and plate is to be lodged such a pipe as was lately described , being either a continuation of the outward branch of the stop-cock , or else firmly fastned to it by sodering or screwing : for by this means , when the sucker is deprest , the air will through the cavity of this pipe , and the stop-cock whereto it is annexed , pass freely by virtue of its own spring out of the receiver into the exhausted cylinder ; though this , and the sucker that moves in it , being not kept as in the second form of the engine under water , the greater care will be needed to keep the air from insinuating it self between them . a good cement , to fasten the receivers to the often mentioned plate of iron , is a thing of no small moment in making the following experiments , of which we imploy differing compositions for differing purposes , some of which are not necessary to be mentioned in that part of this work that now comes forth ; but that which in almost all the following tryals we chiefly make use of , is a well wrought mixture of ( yellow ) bees wax and turpentine , which composition as it serves better than most others to keep out the air , so it has the conveniency , which is no small one , of seldome needing to be heated , and seldomer to be much so ; especially if we imploy a litle more turpentine in winter than in summer , in the former of which seasons , as much , or very near as much of that ingredient as of the wax does well , for as in summer a mixture of three parts of wax to about two of turpentine is more proper . errata . by an oversight a short paragraph was omitted in the . page , importing , that the second figure of the th . plate was designed onely to make some representation of the difference that would appear , if instead of making the . experiment with water , as in the foregoing figure , the tryal was made with quick-silver . so lik wise in pag. . lin . . and . for of the book read of the . pag. ib. l. . read cylinders of equal heights are to one another as their bases . the reader is desired to perfect with his pen the marginal notes referring to the plates as being defective , and also to insert such others as were wholly omitted , according to the following directions ; which could not otherwise be conveniently supplied , without putting a stop to the press . in the margent of page the — d. read see plate the iii. figure the . . r. see plate the iv. figure the . . r. see plate the iii. figure the . . r. plate the iii. fig. the . . see plate the iii. figure the . . r. see plate the v. figure the . . r. see plate the iii. figure the . . against the . line , insert — see the whole baroscope delineated plate the v. fig. the . . against the last line but two , insert — see plate the v. figure the . . against the . line insert — see plate the v. figure the . . against the . line , insert see plate the vi. figure the . . against the . line , insert see plate the vi. fig. the . . r. see the . figure of the . plate : ( adding thereto ) which though made primarily for the . experiment , may facilitate the conceiving of this. . against the . line , insert see plate the vi. figure the . . against the . line , insert see plate the vi. figure the . . against the . line , insert see plate the vi. figure the . . against the . line , insert see plate the vi. figure the . . read see plate the vi. fig. the . . r. see plate the vii . fig. the . . against the . line , insert see plate the vii . figure the . . read see plate the vii . figure the . . r. see plate the viii . fig. the . . r. see plate the iv. fig. the . . r. see plate the viii . fig. the . and . . against the . line , insert see plate the viii . fig. the . and against the last line save one , insert see plate the viii . fig. the . . r. see plate the viii . fig. the . . within lines of the bottom , insert see plate the iv. figure the . the i. plate . the ii plate . a continvation of nevv experiments physico-mechanical , touching the spring and vveight of the air , and their effects . the i. part . written by way of letter , to the right honourable the lord clifford and dungarvan . my dear lord , since i have already in proper places of the physico-mechanical experiments about the air , which i formerly presented your lordship , giv'n you a sufficient account of several things touching the scope , occasion , &c. of my attempt ; it will not be necessary to make a solemn preface to the ensuing experiments . and therefore presuming upon an acceptance , which the favourable entertainment , which your lordship , as well as the publick , was pleas'd to give my first tryals of this kind , encourages me to expect , i shall , without troubling you with any further preface , immediately fall upon a continuation ; especially since your lordship will perhaps wonder , that you have not receiv'd it much sooner , as , indeed , you should have done , if i had been befriended with accommodations and leisure . experiment i. about the raising of mercury to a great height in an open tube , by the spring of a little included air. divers ways have been proposed to shew both the pressure of the air , as the atmosphere is a heavy body , and that the air , especially when compress'd by outward force , has a spring that enables it to sustain or resist a pressure equal to that of as much of the atmosphere , as can come to bear against it , and also to shew , that such air as we live in , and is not condens'd by any humane or adventitious force , has not onely a resisting spring , but an active spring ( if i may so speak ) in some measure , as when it distends a flaccid or breaks a full-blown bladder in our exhausted receiver . but observing that there seems to want a visible experiment to convince those that are not so easily satisfy'd with reasons , though drawn by just consequence from physical or mechanical truths , or even from other experiments , taking notice , i say , hereof , i made the following experiments ; not so much to prevent or removed a scruple no better grounded , as to have a new way of making an estimate by some known and determinate measure of the force of the bare spring of the air , both in its natural state , ( as t is said to be when not compress'd nor ratify'd , more then the free air we breath , ) and according to its several degrees of expansion . we took then a viol , with a neck not very large , and having fill'd about a fourth part of it with quick-silver , we so erected and fastned a long and slender pipe of glass , open at both ends in the neck of the viol , with hard sealing wax , that the lower end reach'd almost to the bottom of the quick-silver , and the upper more then a yard above the viol . then having blown in a little air , to try whether the instrument did not leak , ( which t is very difficult to keep such instruments from doing , ) we conveigh'd it into a long and slender receiver , fit for such an use , and having withdrawn the air as well as we could , we found according to our expectation , that the spring of the air , included in the viol , impell'd up the quick-silver into the erected pipe , to the height of . inches , and having suffer'd the external air to return into the receiver , the quick-silver subsided in the tube , sometimes almost , and sometimes quite as low as the stagnant quick-silver in the viol . for the better illustration of this experiment , thus summarily related , but with the like success , as to the main , several times repeated , we will subjoyn the following observations and notes . i. that we try'd this experiment several times , and the last time in the presence of the famous savilian geometer , d r wallis , who saw the quick-silver in the pipe impell'd up to . inches , being one himself of the measurers ; and though at other times we found it to be much about the same height with the last , yet once it seem'd plainly to be a pretty deal higher ; which yet we specifi'd not , because a mischance took off the mark , which we had made to measure the height by . ii. having once , to try the stanchnesse of the viol , blown in so much air , ( without taking out any thing as we use to do in the like case ) that the air in the cavity of the viol rais'd and kept the quicksilver . inches high in the pipe , when we went on with the rest of the experiment , according to the way above describ'd , we found , by emptying the receiver of air , that we were able to raise the quicksilver in the cane . inches , or somewhat more above that in the viol . iii. sometimes it may happen , that the mercury , when taken very soon out of the receiver , will not appear to have subsided to its first lownesse , which perhaps 't will not sink to in some while after : which is not to be wondred at , since in such a receiver , which contains but little air , the heat of the cement and the iron , imploy'd to melt it quite round the receiver , may impart a little warmth to the air in the viol , which will after return to its former temper . but this accident is neither constant nor necessary to the experiment . iv. t is very remarkable , that if the receiver be fitly stopt , and slender enough ; upon the turning of the stop-cock , to let out the air at the first exuction , the mercury will be impell'd up by the spring of the air in the viol , suddenly flying abroad or stretching it self , so that it will be rais'd several inches above the height it will rest at afterwards , and will make several vibrations up and down before it come to settle , just as the mercury does in the torricellian experiment , ( the bare pressure of the little air doing here to the mercury , what the weight of the atmosphere does there , ) and such motions of the mercury will be made four or five subsequent exuctions , upon the withdrawing of the air in the receiver . but as these grow lesser and lesser , as the spring of the included air grows fainter , so none of them is any thing near so considerable as the vibrations made upon the first suck . v. agreeable hereunto we observ'd , that at the first exuction , when the spring of the included air was yet strong , the mercury would be rais'd by our estimate above half , if not ⅔ of the whole height , whereto 't will at length be brought , ( though that must be according to the bignes of the receiver , and other circumstances , ) and the subsequent exuctions do still adde less and less proportions of height to the mercurial cylinder , and that for two reasons : the one , because the more there is of mercury impell'd into the tube , the greater weight of mercury presses upon the included air : and the other , because the air has so much the more room in the viol to expand it self , whereby its spring must be proportionably weakned . lastly , when we made most of these tryals , i had the curiosity to observe the height of the mercury in a good barometer , and thereby found , that the air was then but light ; its greatest height reaching but to inches , and ⅜ , and its height soon after the tryal , whereof d r wallis was a witnesse , amounting but to . inches . to make an estimate of the quantity of air , that had rais'd the quicksilver to inches , we took the viol that was imploy'd about this experiment ; and having counterpois'd it , whilst it was empty , we afterward fill'd it with water , and found the liquor to weigh . ounces , . drachms , and about . grains ; and then having pour'd out the water , till it was sunk to a mark which we had made on the outside of the glass , to take notice how high the quick-silver reach'd that we pour'd in : and lastly , weighing the remaining water , equal in bulk to the quick-silver , we found it to amount to . ounce , . drachms , . grains ; so that the air , that had rais'd up the mercury , possess'd ( before its expansion ) in the viol the place but of . ounces , and a few odde grains , i. e. of about ¼ of a pint of water . and as for the pipe also , imploy'd about the same experiment , we found its cavity to have about ⅛ part of an inch in diameter . it was one of the uses i hop'd to make of this experiment , that by comparing the several degrees of expansion of air included in the viol , with the respective and increasing heights of the mercury that was impell'd up into the pipe , some estimate might be made of the force of the spring of the air weaken'd by several degrees of dilatation ; but for want of conveniences i forbore to venter upon such nice observations , especially because the pressure of the dilated air , that remains in the receiver , and is external to the air included in the viol , must also be taken into consideration . another use of our experiment may be this : that it may supply us with a considerable argument against some learned men , who attribute the suspension of the quick-silver in the torricellian experiment to a certain rarify'd matter , which some call a funiculus , and whereto others give other names ; which rarify'd substance they suppose to draw up and sustain the quick-silver , in compliance of natures abhorrency of a vacuum . for in the experiment under consideration , the quick-silver being not onely sustain'd at the height of inches in the tube , but elevated thither ; if the cause of this be demanded , it will be answer'd , according to their hypothesis , that the air in the receiver , external to that of the viol , being , by reason of the sucking out of some of it by the pump , more rarified than that in the viol , it draws up to it the quick-silver in the cane , and the more it is rarify'd , the higher it is enabl'd to draw it . but then i demand , whence it comes to pass , that though we can , by persevering to pump , more and more rarifie the little remaining air , or the aëreal substance in the receiver , that in the viol not appearing to be also rarified , yet the air in the receiver does not by virtue of its superadded rarefaction , whereby it exceeds that of the air in the viol , pull up the quick-silver to a greater height in the tube then . inches : for , that this is not the greatest height , to which mercury may be rais'd by this rarefy'd substance , our adversaries must not deny , who tell us , that in the torricellian experiment it sustains a mercurial cylinder of . inches , and ½ , and can raise a cylinder of inches to ½ , or higher , in case that the cylinder be made to vibrate up and down in the tube . and as for those , that will in such cases , as our experiment suggests , have recourse onely to that which they call the fuga vacui , they may please also to consider , that since the quick-silver remains the same , its ascension in the tube will not be available for what they think to be natures purpose ; for , whether it reach higher or lower in the tube , it will adaequately fill no more space in one posture , or in one figure , then in another , in what part soever of the cavity of the receiver it be plac'd . experiment ii. shewing , that much included air rais'd mercury in an open tube , no higher than the weight of the atmosphere may in a baroscope . in the former experiment , by reason of the smalness of the viol , that was employ'd about it , there was so little air included , that the expansion of it so far , as was requisite to impell up the mercury in the pipe to the above mentioned height of . inches , may be probably suspected to have very much weaken'd its spring , and therefore it may be thought , that ( especially considering the great force that several of our experiments manifest imprison'd air to have , ) if there were a greater quantity of air included in the vessel , so that the expansion , sufficient to raise the mercury to the former height , would not need to be considerable , ( because that the capacity of the tube being but the same , the whole included air will be so much the lesse expanded , by how much the more of it there is , ) it seem'd probable that the spring of the air , being but a little weakned by so small a dilatation , would remain strong enough to raise a much taller cylinder of mercury in the tube , and perhaps make the liquor run over into the receiver . but though this suggestion seem probable enough , yet when i consider'd , that the weight of the atmosphere is able to sustain a cylinder of quick-silver but of . inches , or thereabouts , ( in perpendicular height , ) and consequently that the pressure of such a mercurial cylinder is equivalent to that of an atmospherical cylinder of the same bore ; 't was not difficult to conclude , that since the air in a viol , before the mouth is clos'd , has a spring but equal in strength to the weight of the atmospherical pillar that leans upon it , ( for if the spring were too strong for the weight that leans on it , some of the air would get out of the viol , ) a greater viol , and consequently a greater quantity of included air would not be able by its spring to elevate and sustain a longer cylinder of mercury , than the weight of the atmosphere is able to do ; nor indeed altogether so much , because of some little ( though but little ) diminution of the spring by some ( though but a small ) expansion , that the included air suffers , by succeeding in the place of the mercury , that is impell'd up . to clear therefore this matter by an experiment , we took a strong glass-bottle , capable of holding about a quart of liquor , and having put into it a convenient quantity of quick-silver , we erected in it a very long and slender pipe of glass , open at both the ends , and reaching at the lower end beneath the surface of the stagnant mercury , and having fasten'd this pipe in the neck of the bottle , by choaking up that neck very accurately with good cement , that none of the included air might be able to get out , we conveigh'd the whole into a receiver , like that imploy'd about the i. experiment in shape , but much larger , that it might be able to contain so great a vessel ; and then the engine being set a work , we quickly rais'd the quick-silver to a greater height than formerly , and when we saw it come to a stand , we did by the help of some marks , made before hand on the pipe , and by the help of a very long and well divided ruler , measure , with as much care and accurateness as the figure of the vessels would allow us to do , the height of the mercurial cylinder , which we found to be . inches , and about ⅞ , to which abating half an inch , which was rais'd , before the pump was employed , by some air that had been blow'd into the bottle , to try whether it were stanch ; deducting , i say , this half inch of quick-silver , which remain'd in the tube after the external air was let in , ( as well as it had been there before the receiver was exhausted , ) out of the newly mention'd number there remain'd . inches , and neer ⅜ , for the height of the mercury , rais'd by the spring of the air , shut up in the bottle : and then consulting with the above mentioned baroscope , which stood in a window in another part of the house , i found , that the weight of the atmosphere did bear a mercurial cylinder of about . inches and ½ , which was higher by ⅛ than that to which the spring had rais'd the quick-silver in the exhausted receiver : and the difference perhaps would have been greater , if the place , where the experiment was made , had not by its warmth added some little matter to the spring of the air , and if also we could have kept the mercury so long elevated , as to give it leave to discharge its self of those small bubbles , which t is almost impossible in such experiments as this to free quick-silver from , without some help from time . lastly , though we caus'd the pump to be ply'd , to try whether we could not , by the more diligent exuction of the receiver , raise the quick-silver above the height of that which the atmosphere kept sustain'd in the baroscope , yet our labour gave us but a confirmation , that the spring of the air would not raise the mercury higher , then did the weight of the atmosphere , which may not a little confirm the d observation . n b. this was not the onely nor the first experiment we made of this kind , but this being carried on without mischances , ( with which divers others were attended , ) and made with much care , i thought fit to set down this in stead of all , intimating generally about the rest , that they seem'd to agree well for the main with that , which is here recited ; onely there is one thing relating to those other experiments , that seems not altogether unworthy to be taken notice of ; which is , that when our tryals were made in vessels , that contain'd a considerable quantity of air , though upon the exhaustion of the receiver the spring of the included air could not raise the quick-silver to the top of the pipe , yet sometimes by other effects it manifested it self to be very strong , as once or twice by the blowing out or breaking the cork or cement , and other matter that was imploy'd to stop the glass it was shut in ; and once by an accident too memorable to be here past over in silence . i had one day invited d r wallis to see such an experiment as i have been relating , made with ( not a viol , but ) a bottle of green glass , ( such as we use now for wine , ) and or pounds of mercury . after this learned person and i had continued spectators as long as we thought fit , we withdrew into another room , where we had not sat long by the fire , before we were surpriz'd by a suddain noise , which the person , that occasion'd it , presently came running in to give us an account of , by which it appear'd , that this ingenious young man , ( whom i often imploy about pneumatical experiments , and whom i mention'd to your lordship , because i. m. has the honour to be somewhat known to you , ) being desirous in our absence to satisfie the curiosity he had to know , whether the quick-silver could not be rais'd higher in the pipe than i had foretold , plyed the pump so obstinately , that at length , the bottle being not , it seems , every where equally strong , the imprison'd air found it more difficult to make the quick-silver run over at the top of the pipe , than to break the bottle in the weakest place , and accordingly did not onely throw off a piece of the bottle , but threw it with such violence against the large and strong receiver , as broke that also , and render'd it unserviceable for the future . but the doctor and i laying together the pipe , which happen'd to be broken into but few pieces , concluded by the place , to which we were told it reacht when this accident happened , that it had not exceeded , nor indeed fully equall'd the height , to which the weight of the atmosphere might have rais'd it . experiment iii. shewing that the spring of the included air will raise mercury to almost equal-heights in very unequal tubes . having shown in the two former experiments , that the active strength of the airs spring is very considerable , i thought good also to examine , whether or no to the other resemblances in operation between the weight of the free air , and the pressure of the included air , this also may be added , that as the gravitation of the atmosphere is able ( as we shall hereafter prove ) to sustain the mercury at the same height in lesser and greater tubes , seal'd at the top ; so the pressure of the included air may be able to sustain the mercury at the same height in slenderer and in larger tubes , though in the latter it must sustain a far greater weight of mercury than in the former ; provided allowance be made for the weakning , which the spring of the included air must be subject to , by reason that , to succeed in the place of a large cylinder of mercury impell'd up into the greater tube , it must expand it self more , and consequently have its spring more weakned , than if the tube were slender . to prosecute this experiment , i thought on a peculiar shape of vessels , which , if i had been where there is a glass-house , i would have caus'd to be blown for the more convenient trying of two pipes of different bores at the same time . but though i wanted this accommodation , i thought i might well enough show what i intended by imploying successively two tubes of very differing sizes , provided the vessel for the including of the air were the same . wherefore taking the glass bottle , made use of to try the former experiment , and erecting in it after the manner above described a cylindrical pipe of glass , a good deal larger than the former , ( if not as large agen , ) we prosecuted the experiment as we had made it , with the slender tube above mentioned , and found that we were able , by the spring of the air in the bottle , to raise the quick-silver to a considerable height , which , measuring as well as the vessel would allow us , was , by the least estimate that was made of it , ( which was mine ) . inches , and ⅛ , by which it appear'd to want somewhat above an inch of the height of the mercurial cylinder , which the weight of the atmosphere could have sustain'd , as appear'd by the barometer , wherein the quick-silver at that time was about . inches , and ¼ high ; which difference was no more then i expected , considering that , whereas the weight of the atmosphere is still the same when the mercury is at its full height ( and that whether the pipe be great or small ) in a seal'd tube ; the spring of our included air must needs be weakned the larger the tube is , and the higher the liquid metal is impell'd in it , so that it seem'd a considerable phaenomenon , that the spring of so little air should be able to raise the mercury as high within an inch or thereabouts in a wider as in a slenderer tube , since the diameter of the cavity of the former being by our estimate double to that of the latter , ( into which the slender pipe could easily be put as into a case too big for it : ) the greater mercurial cylinder may be suppos'd to have weighed near four times as much as the lesser ; i say , near , because there was an inch difference in their heights : but in case these had been equal , then the solidities of the cylinders would have been to one another as their bases ; and since these , being circular , are in duplicate proportion to their diameters , that is , as the squares of their diameters ; its plain , that if the diameters be as one to two , the squares of them must be as one to four ; and these cylinders consisting of the same mercury , their weights will have the same proportions with their solidities , and consequently would be as one to four , making the abatement formerly intimated for the inch and a little more of mercury , by which the larger cylinder came short of the height of the former . nb. . this and the two former experiments tryed by us with quick-silver , may be also tryed with water ; but besides that we could hardly procure tubes long enough for such tryals , we were not very sollicitous about it : for if we attentively enough consider , what has been already deliver'd , and the proportion in specifick gravity betwixt water and quick-silver , ( whereof the latter is near . times as heavy , bulk for bulk , as the former , ) 't will not be difficult to foresee the event of such experiments , which he , that has a mind to make , should be furnish'd not onely with long tubes , but with capacious vessels to shut up the air in . else the air will be so far expanded before the water has attain'd near the height , to which the weight of the atmosphere may raise it , that the experiments will not seem to succeed near so well with water , as ours did with quick-silver . . we thought it worth trying , whether , when the included air had rais'd the great cylinder of mercury to the utmost height , it could elevate it to , by the spring it then had ; it would not be brought to raise the quick-silver yet higher , if , notwithstanding the expansion it had already , there were an agitation made by the heated corpuscles of the same air. and in pursuance of this curiosity having caus'd an hot iron and a shovel of kindled coals to be held near the opposite parts of the receiver , we perceiv'd after a while , that the mercury ascended ⅛ of an inch or better above the greatest height it had reach'd before . but conjecturing that it would have risen higher , were it not that whilst the application of the hot bodies was making , some particles of air had unperceivably stolen into the receiver , i caus'd the pump to be ply'd again to withdraw the air , i suspected to have got in , by which means the mercury was quickly rais'd ⅝ of an inch , ( or better , ) by virtue of this adventitious spring , ( if i may so call it , ) which the included air acquir'd by heat , and i made no doubt , that it might have been rais'd much higher , but i was unwilling by applying a less moderate heat to hazard the breaking of my glasses , in the place i then was in , where such a mischance could scarce have been repair'd . experiment iv. about a new hydraulo-pneumatical fountain , made by the spring of uncompress'd air. i shall now add such an application of the principle whereon the former experiment was grounded , as i should scarce think worth mentioning in this place , were it not that besides that divers virtuosi seem not a little delighted with it , it may for ought i know prove to be of some philosophical use ( to be pointed at hereafter . ) we took a glass-bottle with a convenient quantity of water in it , and fitted this bottle with a slender glass-pipe open at both ends , and about three foot long , which was so plac'd , that the lower orifice was a good way beneath the surface of the water , and the pipe it self passed perpendicularly upwards through the neck of the bottle , which neck was , by the pipe and by good hard cement imploy'd to fill the space betwixt the pipe and the inside , so well and firmly clos'd , that no water or air could get out of the bottle , nor no externall aire could get into it , but by passing through the pipe. this instrument was convey'd into a large receiver shap'd like a pear , of which a good part of the blunt end , and a small part of the sharp end are cut off by sections parallel to the horizon , and consequently to one another . and because this receiver was not ( nor ought to be ) long enough to receive the whole pipe , there was cemented on to the upper part of it a smaller receiver of white glass , of such a length and bigness , that the upper end of the pipe might reach to the middle of its cavity , or thereabouts , and that the motions of the springing water might have a convenient scope , and so be the better taken notice of . this double receiver being cemented on to the engine , a little of the air was by one suck of the pump drawn out from it , by which the pressure of the remaining air being weakned , it was necessary , that since the air included in the bottle had not its spring likewise weakned , it should expand it self , and consequently impell up the water in the same bottle through the pipe , which it did so vigorously , as to make it strike briskly at first against that part of the top of the smaller receiver , which was just over the orifice of the pipe. but after it had a while made the water thus shoot up in a perpendicular line , as the spring of the air in the bottle grew by that airs dilatation to be weaken'd , the water would be impell'd up less strongly and less directly , till the air in the bottle being as much expanded as that in the receiver , the ascent of the water would quite cease , unless by pumping a little more aire out of the receiver we renew'd it again . about the making of this experiment these particulars may be noted . . t is convenient , that the upper part of the pipe be made ( as it easily may be at the flame of a lamp ) very slender , that the water having but a very small orifice to issue out at , may be spent but slowly , and thereby make the experiment last so much the longer . . you may , if you please , in stead of making the upper part of the pipe slender , as was just now directed , cement on to it a top either of glass or brass , consisting of three or more very slender pipes , with a pin-hole at the end of each , that one of these pointing directly upwards , and the others to the right hand and to the left , the water may spin out several ways at once , by which kind of branched pipes we have sometimes imitated the jets d' eau ( as the french call them ) and artificial fountains of gardens and groto's . . in regard that so short a cylinder of water , as exceeded not the length of our glass pipe , could not make any considerable resistance to the expansion of the included air , it was thought and found safe enough to imploy in stead of a strong glass-bottle a much larger viol , without being sollicitous about its shape , or that it should be very strong , and by this means we could make this pleasant spectacle last a great while , especially if we also made use of the expedient to be mentioned in the following note . . if you find that the included air have by expanding it self too much weaken'd its spring , whilst there yet remains with it a good quantity of water in the bottle or viol , you may reinforce the pressure of the air by onely turning the stop-cock , and letting in what air you think fit to the exhausted receiver : for upon the admission of this new air , the air in the receiver will press sisted on ? if as a law-maker , then even the sanction will continue , by which such laws as these obliged formerly : so they will still oblige as laws , whilst the same reason continues for which god was at first pleas'd to impose them . if as an infallible judge of reason ; still it will follow , that whilst the reason holds , they will be so far from being made unlawful in such particulars wherein the reason does indeed hold , that their performance will still be acceptable to god , tho' not commanded by him . either way of explication is sufficient to overthrow his whole way of reasoning , as manag'd by our adversaries . but what if we should turn this way of reasoning us'd by the apostles , against our adversaries ? what if we should conclude , that because instrumental musick was us'd then in their temple sacrifices , therefore it should still be at least fit and acceptable in our present eucharistical sacrifices ? i cannot foresee what they could say , why we should not have reason'd as the apostles did ; or how the apostles could blame us for doing so ; or why our adversaries should blame us ; who profess themselves such enemies of impositions , if they did not impose upon us more than the apostles , in so easily condemning matters of this nature as unlawful . they can pretend no more condemnation in other places of the writings of the apostles in this case , than in those others wherein the apostles themselves allow this way of arguing . and i know no reason from the natures of the things themselves , that even our adversaries can pretend to be temporary , or that will not make instrumental-musick as suitable to our present worship , as it was to that of the apostles . no sort of sacrifices were more proper for hymns than those that are eucharistical , and such all ours are now , but were not so in the days of the apostles . and the use of hymns neither is , nor can be denied by our adversaries , as well in the private synaxes of the apostolical christians , as in the worship of the temple . the hymn to christ as a god in pliny , appeal'd to in the latter end of the second century as a very early evidence of the belief of his deity , seems to have been joined with the eucharist . for pliny tells us , on the same occasion , of the covenant the christians entred into against all the liberties us'd by wicked persons . and the publick singers are mention'd in the earliest distinct accounts we have of their offices , not as newly introduc'd , but as actually obtaining without any memory of a late original . had the reasons of the things been all that had been requisite for raising of the affections , i cannot conceive any need our adversaries can pretend for singing : that does no otherways contribute to the raising of the affections , than as the assistance and improvement of the imagination may be supposed to contribute to it . the singing does not add a new reason , nor impose the old ones , why the affections should be raised . but however , they do dispose the affections to follow reason , more readily and more vigorously than they would if they had not the assistance of a favourable imagination : and that by the nature of the things themselves ; and in that regard , musick instrumental , also was acknowledg'd to have the same influence that singing had by the imagination over the affections ; and to add to the advantages of singing vocally : so it was , that david's playing on the harp cured saul of the evil spirit , by curing that melancholy which disposed him to receive the influences of the evil spirit : so it was , that the like use of instrumental musick dispos'd elisha for the influences of the good spirit , by composing that passion which his zeal against the idolatry of the king of israel had put the prophet into ; it made him capable of being acted by the spirit of prophesy : for chearfulness of temper is one of the dispositions requir'd by the rabinnical jews themselves , for fitting men for prophecy . that may possibly be the reason why the scriptures mention instrumental musick as receiv'd in the schools of the prophets , especially when they were actually prophesying ; as it should seem to dispose them for the freer influences of the divine spirit . the singing hymns to such instruments is call'd prophesying , in the places now mention'd . so far the nature of the spiritual worship of the gospel , is from superseding this assistance of instrumental musick , as our adversaries would have us believe , that on the contrary i had done ) not satisfied about them . onely he sometimes ( as i also did ) observ'd the salient water to describe part of a line perfectly enough parabolical , with which sort of curves he has been particularly conversant . this made me resolve for further satisfaction to attempt by another contrivance , ( of whose success , if i can procure the implements i need , your lordship may expect an account , ) what the figures will be not onely of salient water , but mercury , and other liquors ; and that when the receiver is much better exhausted , then it was necessary it should be in the foregoing experiment . experiment v. about a way of speedily breaking flat glasses , by the weight of the atmosphere . for the more easie understanding of some of the subsequent tryals , it will be requisite in this place to mention among experiments about the spring of the air the following phaenomenon belonging to its weight . this is one of those that is the most usually shown to strangers , as a plain and easie proof both that the weight of the incumbent air is considerable , and that the round figure of a receiver doth much more conduce to make an exhausted glass support that weight , than if the upper part of the receiver were flat . to make this experiment we provided a hoop or ring of brass of a considerable thickness , whose height was ½ , or inches , and the diameter of whose cavity as well at the upper as lower orifice ( should have been just . inches , but through the errour of the workman ) was . inches and / . to this hoop we successively fasten'd with cement divers round pieces of glass , such as is used by glasiers ( to whose shops we sent for it ) to make panes for windows , and thereby made the brass-ring with its glass-cover a kind of receiver , whose open orifice we carefully cemented on to the engine ; and then we found , as we had conjectured , that usually at the first exuction ( though sometimes not till the second ) the glass-plate would be broken inwards with such violence , as to be shatter'd into a great multitude of small fragments , and ( which was remarkable ) the irruption of the external air driving the glass inwards did constantly make a loud clap , almost like the report of a pistol . which phaenomenon , whether it may help us to discover the cause of that great noise , that is made upon the discharging of guns , ( for the recoyl seems to depend upon the dilatation and impulse of the powder , ) i must not stay to consider . experiment vi. shewing , that the breaking of glass-plates in the foregoing experiment , need not to be ascrib'd to the fuga vacui . though i long since inform'd you , that in the experiments i then presented your lordship , it was not my purpose to deliver my own opinion whether there be a vacuum , or no , and though i do not in this tract intend to declare my self either way ; yet , that i may on this occasion also show , that the pressure of the air may suffice to account for divers phaenomena , which according to the vulgar philosophers must be referr'd to natures abhorrency of a vacuum , i will illustrate the foregoing experiment by another , the substance whereof is this . that if , instead of the above mentioned brass hoop , both whose orifices are of equal breadth , you imploy a hollow ( but taller ) piece of brass , or ( which is more easily made ) of latton , shap'd like a conus iruncatus , or a sugar-loaf , whose upper part is taken off parallel to the bottom ; and if you make the two orifices of a breadth sufficiently unequal , as if the larger being made as wide as that of our brass-hoop , the straiter were less than an inch in diameter ; you will find , that if this piece of metal be made use of , as the other was in the foregoing experiment , the flat glass cemented on to the orifice , will be easily broken , as formerly when t is fastned to the wider orifice ; but if the straiter orifice be turn'd upward , the glass that covers it , if it be of a due thickness , ( though no thicker than the former , ) will remain entire , notwithstanding the withdrawing of the air from beneath it : which seems sufficiently to argue , that t is not precisely natures abhorrency of a vacuum , that is the cause why glasses are usually broken in such experiments , since whether the wider or the narrower orifice be uppermost , and cover'd , ( the metalline part of the vessel being the same , and onely varying its posture , ) the capacity of the exhausted vessel will be equal ; and therefore nature ought to break the glass as well in one case as the other , which yet the experiment shows she does not . wherefore this diversity seems much better explicable by saying , that when the wider orifice is uppermost , the glass that covers it must serve for the basis of a large atmospherical pillar , which by its great weight may easily force the resistance of the glass : whereas when the smaller orifice is uppermost , there leans upon its cover but so slender a pillar of the atmosphere , that the natural tenacity or mutual cohaesion of parts in the glass is not to be surmounted by a weight that is no greater . experiment vii . about a convenient way of breaking blown bladders by the spring of the air included in them : the foregoing experiments having sufficiently manifested the strength of the airs spring upon fluid bodies , i next thought fit to try , whether the force of a little included air would also upon consistent and even solid bodies emulate the operations of the weight of the atmosphere . in the prosecution of which enquiry we thought fit to make two sorts of tryals : the one , where the air is included in the bodies , on which its spring does work ; and the other , where t is external to them . of the first sort are this th , and the two following experiments ; and of the second sort are some other tryals , to be comprehended under the th experiment . having formerly mention'd to your lordship , that we were several times able ( though sometimes not without much difficulty ) to make a blown bladder break with the spring of its own air ; i should not think it worth while to say any thing here about the same phaenomenon , but that ( besides that it seems odd enough , and is not unpleasant to many spectators , ) it may deserve not to be wholly neglected , because a good way to break bladders in the much exhausted receiver , may sometimes prove an useful expedient , especially in such cases where the experimenter ( who sometimes either is not skilful enough , or well enough furnish'd with accommodations to regulate the ingress of the air ) would very suddainly supply the receiver with fresh air , when it has been much emptied , without danger of letting in too much air from without . not to mention , that the air , included in the bladder to be broken , may be so mingled with streams , or imbu'd with divers qualities , as to be much fitter than common air for some particular purposes . we shall then for the affinities sake between this tryal and the former , subjoyn now the way , by which we seldom fail'd of breaking bladders in our emptied receivers . for this purpose , the blown bladder that was to be burst , having the neck very closely and strongly tyed , was kept a pretty while in the receiver , whilst the air was pumping out , and then taken out again , that , now the fibres were stretcht and relax'd , the capacity being lessen'd by a new ligature that i order'd to be strongly made near the neck , the bladder might be lessen'd though the air were but the same , and the membrance being not so capable of yielding as before , upon the second exhaustion of the receiver the bladder in it would break , far more easily then otherwise , and perhaps be oddly enough lacerated . we sometimes also varied this way of disposing bladders to be burst , by omitting the preparatory putting in of the bladder into the receiver , and onely taking it in a little near the neck , that , the bladder having not been blown very full at first , the tension of the included air might be greater . but this last way is to be made use of , when the thing we desire is , that the bladder by breaking at a certain time may part with its air , and not when t is onely to give an instance of the force of the spring of uncompress'd air against the sides of the vessel that contain it . experiment viii . about the lifting up a considerable weight by the bare spring of a little air included in a bladder . you will easily believe , that the force imploy'd ( in the foregoing experiment ) by the air , to break the well blown bladders t is included in , is considerable , if i here adde , that a small quantity of air , which will not fill ¼ of a bladder , will not onely serve to blow it quite up , but will manifestly swell it , though that effect be oppos'd not onely by the resistance of the bladder it self , but by a considerable weight tied to the bottom of it , as in the following experiment . we took a middle siz'd bladder ( of a hog or sheep , ) and having press'd out the air , till there remain'd but about a fourth or fifth part ( by guess , ) we caus'd the neck to be very strongly tyed up again : also round about the opposite part of the bladder , within about an inch of the bottom , we so strongly tyed another string , that it would not be made to slip off by a not inconsiderable weight we hung at it . then fastning the neck of the bladder to the turning key , we convey'd the bladder and the weight hanging at it into a large receiver , in which when it began to be pretty well exhausted , the air within the bladder being freed from the wonted pressure of the air without it , did by its own spring manifestly swell , and thereby notably shorten the bladder that contain'd it , and by consequence visibly lifted up the weight , ( that resisted that change of figure , ) which exceeded pound of . ounces to the pound . after that we took a larger bladder , and having let out so much air , that it was left lank enough , we fasten'd the two ends of it to the upper part of the receiver , ( for which else it would have been too long , ) and tyed a weight ( but not the same ) so as that it hung down from the middle of the bladder ; then exhausting the receiver as before , though the bladder , and this new weight which stretcht it , reach'd so low , as that for a while we could scarce see whether it hung in the air or no , yet at length we perceiv'd the bladder to swell , and concluded that it had lifted up its clog about an inch ; which was confirm'd by the return we permitted of the air into the receiver , upon which the bladder became more wrinkled than before , and the weight descended , which being taken off , and weighed in a statera , amounted to abovt pounds . we would have reiterated the experiment , but so heavy a weight having broken the bladder , we were discouraged from proceeding any farther , especially in regard of the difficulty of bringing by this contrivance the strength of the airs spring to any exact computation , though it sufficiently shews what i design'd it should , namely that the spring of a little included air may be able even in so slight a contrivance to raise a great weight . whether this experiment may any way illustrate the motion of muscles , made by inflation , contraction , &c. it belongs not to this place to consider . experiment ix . about the breaking of hermetically seal'd bubbles of glass by the bare spring of their own air. i shall premise to the following tryals an experiment , wherein uncompress'd air is made by its own bare spring to break the solid body it self t is shut up in . and this i the rather set down before the subsequent tryals , because in our already publish'd physico-mechanical experiments mention has been made of this tryal , as of one that we could not then make to succeed ; we have since , imploying smaller receivers , made it often enough prosperously , somewhat to the wonder of eminent virtuosi , who confess'd to me they had made frequent and divers attempts to perform the same thing , without ever succeeding in any of them . but it will not be requisite to multiply relations about this particular , and therefore i shall set down but this one , which i meet with among my loose notes . a large glass bubble hermetically seal'd being put into the receiver , and the air drawn out as much as in usual operations , and somewhat more , though i told the company before hand that i had several times observ'd , that such bubbles would not break immediately , but somewhile after the withdrawing the air from about them , yet this continued so long entire after we had left off pumping , that presuming it had been blown too strong , i began to dispair of the experiments succeeding ; when , whilst we were providing something else to put into the receiver , and as i guess'd . minuts after the pump had been let alone , the bubble surpriz'd us with its being broken with such violence by the spring of the included air , that the fragments of it were dash'd every way against the sides of the receiver , and broken so very small , that when we came to take it up , the powder was by the by-standers compar'd to the small sand wont to be imploy'd to dry papers , that have been newly writ upon with inck. the reason why the bubble broke so slowly i cannot now stay to propose , no more then to examine whether the difficulty of breaking vessels of glass , no thicker then these bubbles , proceed from some weakning of the spring of imprisoned air , by its stretching a little the including glass , ( for in another case we have observ'd this glass to be stretchable by the pressure of air ; ) or from hence , that 't was very hard , as i have elsewhere mention'd , to avoid rarifying the air a little , and consequently weakning its spring , by the heat that was necessary to be imploy'd about the sealing up the bubble . experiment x. containing two or three tryals of the force of the spring of our air uncompress'd upon stable and even solid bodies , ( whereto t is external . ) in prosecution of the enquiry propos'd in the title , we made ( among others ) the following tryals . the i. tryal . . we took the brass-hoop , mention'd in the th experiment , ( whose diameter is somewhat above . inches , ) and having caus'd a glazier to cut some plates of glass , such as are used for making the quarrels of windows , till he had brought them to a size , & a roundness fit to serve for covers to that brass-hoop , we carefully fasten'd one of them with cement to the upper orifice of the hoop or ring , and then cementing the lower orifice to the engine , so that the vessel , compos'd of the metal and glass , serv'd for a small receiver ; we whelm'd over it a large and strong receiver , which we also fasten'd on to the engine with cement after the usual manner . by which contrivance it was necessary , that when the pump was set on work , the included receiver ( of brass and glass ) should have its air withdrawn , and yet the air in the larger receiver should not be pump'd out but by breaking through the glass , so that the internal air of the metalline receiver ( as we may call it for distinctions sake ) being pump'd out , the glass plate , that made part of that receiver , must lye expos'd to the pressure of the ambient air shut up in the other receiver , without having the former assistance of the now withdrawn air to resist the pressure ; wherefore , as we expected , at the first or second exuction of the air , included in the small metalline receiver , the glass-plate was , by the pressure of the incumbent air , contain'd in the great receiver , broken into an pieces , which were beaten inwards into the cavity of the hoop . the ii. tryal . . this done , to shew that there needed not the spring of so great a quantity of included air to break such glasses , we took another roundish one , which , though wide enough at the orifice to cover the brass ring & the new glass-plate that we had cemented on it , was yet so low , that we estimated it to hold but a th part of what the large receiver , formerly imploy'd , is able to contain ; and having whelm'd this smaller vessel , which was shap'd like those cups they call tumblers , over the metalline receiver , and well fasten'd it to the engine with cement , we found that though this external receiver had a great part of its cavity fill'd by the included one , yet when this internal one was exhausted by an exuction or two , the spring of the little air that remain'd , was able to break the plate into a multitude of fragments . the iii. tryal . . because the glass-plates hitherto mention'd seem'd not so thick , but that the pressure of the included air might be able to give considerabler instances of its force ; in stead of the metalline receivers hitherto employed , we took a square bottle of glass , which we judg'd to be able to contain about a pint ( or pound ) of water , and which had been provided to keep subtle chymical liquors in , for which use we are not wont to choose weak ones . this we inverted , and apply'd to the engine as a receiver , over which we whelm'd the large receiver formerly mention'd ; and having cemented it on , as in the foregoing experiments , we set the pump on work to empty the internal receiver , ( or square bottle , ) by which means the withdrawing of the air , and the figure of the vessel ( which was inconvenient for resisting ) suffer'd the pressure of the air included in the external receiver to crush the viol into a great number of pieces . and to vary this experiment , as we did that of breaking the metalline receivers , we took another glass of the shape and about the bigness of the former , and having apply'd it to the engine as before , and cover'd it with a receiver that was little higher than it self , we found , that upon the exhaustion of the air the second square glass was likewise broken into many fragments , some of which were of so great a thickness , as mov'd some wonder , that the bare pressure of the air was able to break such a vessel , though probably the cracks , that reacht to them , were begun in much weaker parts of the glass . nb. . the bottoms and the necks of both these square bottles were entire enough ; by which it seem'd probable , that the vessels had been broken by the pressure of the air against the sides , which were not onely thinner than the parts above named , but expos'd a larger superficies to the lateral pressure of the air , than to the perpendicular . . we observ'd in one of the two last experiments , that the vessel did not break presently upon the last exuction that was made of the included air , but a considerable time after , which it seems was requisite to allow the comprest parts of the glass time to change their places ; and this phaenomenon i therefore mention , because the same thing that here happen'd in the breaking a glass inwards by the spring of the air , i elsewhere observ'd to have happen'd in breaking a glass outwards by the same spring . . to confirm , that it is the spring of the external receivers air that is the agent in those fractures of glasses , and to prevent or remove some scruples , we thought fit to make this variation in the experiment . we applyed a plate of glass , just like those formerly mentioned , to the brass-hoop ; but in the cementing of it on , we plac'd in the thickness of the cement a small pipe of glass of about an inch long , whose cavity was not so big as that of a straw , and which being left open at both the ends might serve for a little channel , through which the air might pass from the external receiver to the internal ; over this we whelm'd one of the small receivers above mentioned , & then , though we set the pump on work much longer then would have needed if this litle pipe had not been made use of , we found , as we expected , that the internal receiver continued entire , because the air , whose spring should have broken it , having liberty to pass through the pipe , and consequently to expand it self into the place deserted by the air pump'd out , did by that expansion weaken its spring too much , to retain strength enough to break the metalline ( or internal ) receiver . but here t is to be noted , that either the pipe must be made bigger than that lately mentioned , or the exuction of the air must not be made by the pump as nimbly as we can , or otherwise the plate of glass may be broken notwithstanding the pipe ; because the air contain'd in the external receiver , having a force much greater than is necessary to break such a plate , it may well happen ( as i have sometimes found it do ) that if the air be hastily drawn out of the internal receiver , that air , which should succeed in its room , cannot get fast enough out of that external receiver through so small a pipe , and the air remaining in that external receiver will yet retain a spring strong enough to break the glass . to illustrate which , i shall propose this experiment , that sometimes , when i have at the flame of a lamp caus'd glass bubbles to be blown with exceeding slender stems , if they were nimbly remov'd out of the flame whilst they were ignited , they would according to my conjecture be either broken , if they cool'd too fast ; or compress'd inward , if they long enough retain'd the softness they had given them by fusion . for the air in the bubble being exceedingly rarified and expanded , whilst the glass is kept in the flame , and coming to cool hastily when remov'd from thence , looses upon refrigeration the spring the heat had given it , and so , if the external air cannot press in fast enough through the too slender pipe , there will not get in air enough to resist the pressure of the atmosphere , and therefore if this pressure find the bubble yet soft , it will press it a little inwards , and either flatten it , or make a dimple in it , though the orifice of the pipe be left open . experiment xi . shewing , that mercury will in tubes be raised by suction no higher then the weight of the atmosphere is able to impell it up . t is sufficiently known , that the common opinion of philosophers , and especially of those which follovv aristotle , has long been , and still is , that the cause of the ascension of water upon suction , and particularly in those pumps , where the water seems of its own accord to follow the rising sucker , is natures abhorrency of a vacuum . against this receiv'd opinion divers of the modern philosophers have oppos'd themselves . but as some of them were vacuists , and others plenists , they have explicated the ascension of water in sucking-pumps upon very different grounds ; so that many ingenious men continue yet irresolv'd in this noble controversie . wherefore though i have formerly made , and now renew a solemn profession , that i do not in this treatise intend to declare either for or against the being of a vacuum ; and though i have * elsewhere occasionally acknowledg'd my self not to acquiesce fully in what either the ancient or the modern philosophers have taught about the adequate cause of suction ; ( in the assigning of which , i think , i have shown them to have been somewhat deficient , ) yet since i think some experiments , of importance to this controversie , may be better made by the help of our engine , than they have been by any instrument i have yet heard of , i shall now adde the tryals i made , to shew both that whether there be or may be a vacuum or not , there is no need to have recourse to a fuga vacui to explicate suction ; and also that whatever other causes have by gassendus and cartesius been ingeniously propos'd to explicate suction , it seems to depend clearly upon the weight of the atmosphere , or in some cases upon the spring of the air ; though i deny not , that other causes may contribute to that pressure of the air , which i take to be the grand and immediate agent in these phaenomena . we took a brass-pipe bended like a siphon , and fitted at the bigger end with a stop-cock &c , as is delineated in the figure , ( which instrument for brevities sake i often call an exhausting ( or sucking ) siphon , ) and to the slender end of this we fastned with good cement the upper end of a cylindrical pipe of glass , of about fifty inches long , and open at both ends , and having the lower end open into a glass of stagnant quick-silver , whose upper superficies reacht a pretty deal higher than the immerst orifice of the glass cane . these things being thus prepared , we caus'd the pump to be set on work , whereby the air being by degrees drawn out of the exhausting siphon , and consequently of the glass-cane that open'd into it ; the stagnant mercury was proportionably impell'd up into the glass-pipe , till it had attain'd to its due height , which exceeded not . inches . and then , though there remain'd in the upper part of the pipe above inches unfill'd with quick-silver , yet we could not by further pumping raise that fluid metal any higher . by which it seems manifest enough , that whatever many learned men have taught , or others do yet believe about the unlimited power that nature would exercise , to prevent what they call a vacuum ; yet this power has its bounds , and those depend not so much upon the exigency of that principle , which the school-men call a fuga vacui , as upon the specifick gravity of the liquor to be rais'd by suction . for confirmation of which , we substituted in stead of the stagnant mercury a bason of water , and though instead of the many sucks we had fruitlesly imploy'd to raise the quick-silver above the lately mentioned height , we now imploy'd but one exsuction , ( or less then a full one , ) which did but in part empty the exhausting siphon : yet the water upon the opening of the stop-cock was not onely impell'd to the very top of the glass-cane , but likewise continued running for a good while through the exhausting siphon , and thence fell upon the plate of the engine ; so that it seem'd an odd spectacle to those that knew not the reason of it , to see the water running very briskly of its own accord as they imagined out of the shorter leg of a siphon ; especially that leg being perhaps not above a a quarter so long as the other . and here i must not omit this considerable circumstance , that though sometimes in the torricellian experiment i have observ'd the mercury to stand at thirty inches , and now and then above it , yet the height of the mercury elevated in our glass-cane appear'd not , when measured , to reach fully . inches and a quarter , which i thought it was not difficult to render a reason of , from the varying weight of the atmosphere ; and accordingly consulting the baroscope , ( that stood in another room , ) i found the atmosphere to be at that time somewhat light , the quick-silver in it being in height but . inches and an eighth , which probably would have been the very height of the quick-silver rais'd by the engine , if it had had time by standing to free it self from bubbles . from whence we may conclude , that suction will elevate liquors in pumps no higher then the weight of the atmosphere is able to raise them , since the closeness requisite in the pump of our engine to be stanch makes it very unlikely , that by any ordinary pump a more accurate suction can be effected . i have nothing to adde about the related experiment but this one ; that it may afford us a notable confirmation of the argument we formerly propos'd against them , that ascrib'd the elevation and sustentation of the quick-silver in the torricellian experiment to a certain rarified air , which the more highly it is rarified , the greater power it acquires to attract quick-silver , and other contiguous bodies ; for in our experiment though by continuing to pump we can rarifie or distend more and more the air in the exhausting siphon , yet we were not able to raise the mercury above inches , ( which exceeds not the height to which the atmosphere is able to elevate it , ) and this , though , the stagnant mercury being exposed to the free air , it cannot be pretended ( as in some other cases it may , though not satisfactorily , be done ) that the mercury cannot be raised higher , without offering violence to the body incumbent on the stagnant mercury : for in the experiment we are considering if nature should raise the quick-silver higher and higher in the pipe , to succeed in the room of the air that is withdrawn ; the formerly stagnant mercury , that would on this occasion be rais'd , might be immediately succeeded by the free and undilated air , so that nature would be put to offer violence to the quick-silver onely , which if she were scrupulous to do , what ayl'd her to raise it ( as she did in our tryal ) against the inclinations of so ponderous a body , to above . inches high ? annotation . though the exhausting siphon , mentioned at the beginning of this experiment , may be easily enough conceiv'd by an attentive inspection of the figure , yet because i frequently make use of it in pneumatical experiments , t will not be amiss to intimate here once for all these three particulars about it . . that though the bending pipe its self may be for some uses more conveniently made of glass than of metal , because the transparency of the former may inable us to discover what passes in it ; yet for the most part we choose to imploy pipes of the latter sort , because the others are so very subject to break . . that t is convenient to make the longer leg of the siphon a little larger at the bottom than the rest of the pipe usually needs to be , that it may the more commodiously admit the shank of a stop-cock , which is to be very carefully inserted with cement ; by seasonably turning and returning of which stop-cock , the passage ( for the air ) between the engine and the vessel to be exhausted is to be opened and shut . . that though we sometimes content our selves to apply immediately the brass siphon its self to the engine , by fastning with cement the external shank of the stop-cock to the orifice of the little pipe , through which the excuction of the air is made ; yet the bended pipe alone , if it be not almost constantly held , is so apt to be loosen'd by the motion of the engine , and the turning of the stopcock , ( which frequently occasions leaks , and disturbs the operation , ) that for the most part we make use of a siphon consisting of a brass pipe , and stop-cock , and a glass of , , or inches in height , and of some such shape ( for it need not be the very same ) as that represented in the figure : for by this means , though the exhaustion is because of this additional glass , somewhat longer in making , yet it is more securely and uninterruptedly carried on by reason of the stability , which the breadth of the lower orifice of the glass gives to the whole instrument . besides which , we have these other conveniences , that not onely the siphon is hereby much lengthned , which in divers tryals is very fit ; but also that we may commodiously place in the glassie part of this compounded syphon a gage , whereby to discern from time to time how much the air is drawn out of the vessel to be exhausted . experiment xii . about the differing heights whereto liquors will be elevated by suction , according to their several specifick gravities . if , when i was making the foregoing experiment , i had been able to procure a pipe long enough , i had tried to what height i could raise water by suction , though i would have done it rather to satisfie others then my self , who scarce doubted , but that as water is ( bulk for bulk ) about times lighter than quick-silver : so it would have been rais'd by suction to about four or five and thirty foot , ( which is times as high as we were able to elevate the quick-silver , ) and no higher . but being not furnished for the tryal i would have made , i thought fit to substitute another , which would carry the former experiment somewhat further . for whereas , in that , we shew'd how high the atmosphere was able by its whole gravitation to raise quick-silver ; and whereas likewise that , which appears in monsieur paschals experiment , is , at what height the whole weight of the atmosphere can sustain a cylinder of water : by the way that i thought on , it would appear , ( which hath not yet ( that i know of ) been shewn , ) how a part of the pressure of the air would in perpendicular pipes raise not onely the two mentioned liquors , but others also to heights answerable to the degree of pressure , and proportionable to the specifick gravities of the respective liquors . to make this tryal the more clear and free from exceptions , i caus'd to be made and inserted to the shorter leg of the above mentioned exhausting siphon a short pipe ; which brancht it self equally to the right hand and the left , as the adjoyning figure declares . in which contrivance i aim'd at these two conveniences : one that i might exhaust two glass-canes at the same time ; and the other , to prevent its being surmis'd that the engine was not equally applied to both the glasses to be exhausted . this additional brass-pipe being carefully cemented into the sucking syphon , we did to each of its two branches take care to have well fastned with the same cement a cylindrical glass of about inches in length , ( that being somewhat near the height of our exhausting syphon above the floor , ) the lower orifice of one of these two glasses being immerst in a vessel of stagnant mercury , and that of the other in a vessel of water , where care was taken by those i imploy'd , that as the tubes were chosen near of a bigness , ( which yet was not necessary , ) so the surfaces of the two different liquors should be near of a height . this being done , we began to pump warily and slowly , till the water in one of the pipes was elevated to about inches , and then measuring the height of the quick-silver , in the other pipe above the surface of the stagnant quick-silver , we found it to be almost inches ; so that the water was about times as high as the quick-silver . and to prosecute the experiment a little further , we very warily let in a little air to the exhausting syphon , and had the pleasure to see the two liquors proportionably descend , till turning the stop-cock when the water was about inches high , we thereby kept them from sinking any lower , till we had measured the height of the quick-silver , which we found to be about one inch . we tried also the proportion of these two liquors at other heights , but could not easily measure thē so well as we did at those newly mentioned ; and therefore though there seem'd to be some slight variation , yet we lookt upon it but as what might be well imputed to the difficulty of making such experiments exactly ; and this displeas'd me not in these tryals , that whereas it was observ'd , and somewhat wondred at , that the quick-silver for the most part seem'd to be somewhat ( though but a very little ) higher then the proportion of to required , i had long before by particular tryals found , that though and be the nearest of small integer numbers that express the proportion between the specifick gravities of quicksilver and water , yet the former of those fluids ( or at least that which i made my tryals with ) is not quite so heavy as this proportion supposes , though i shall not here stay to determine precisely the difference , having done it in another tract , where the method i imployed in the investigation of it is also set down . the above mentioned experiment , made by the help of our engine , as to quick-silver and water being confirmable by tryals ( to be by and-by mentioned ) made in other liquors , affords our hypothesis two considerable advantages above the vulgar doctrine of the schools , ( for i do not apply what follows to all the plenists , ) who ascribe the ascension of liquors by suction to a traction made ob fugam vacui , as they are wont to speak . for first it is manifestly agreeable to our doctrine , that , since the air , according to it , is a fluid that is not void of weight , it should raise those liquors that are lighter , as water , higher then those that are ponderous , as quick-silver ; and that answerably to the disparity of their weights ▪ and secondly , there is no reason why , if the air be withdrawn by suction from quick silver and water , there should be less left a vacuum above the one then above the other , in case either of them succeed not in the place deserted by the air , and consequently when the air is withdrawn out of both the forementioned glass-pipes , if there would be no vacuum in case no liquor should succeed it , why does nature needlesly to prevent a vacuum make the water that is an heavy body ascend contrary to its own nature , according to which it tends towards the center of the earth ? and if the succeeding of a liquor be necessary to prevent a vacuum , how chance that nature does not elevate the quick-silver as well as the water , especially since t is manifest by the foregoing experiment that she is able to raise that ponderous liquor above inches higher than she did in the experiment we are now discoursing of . perhaps it would not be amiss to take notice , on this occasion , that among other applications of this experiment it may be made somewhat useful to estimate the differing gravities of liquors , to w ch purpose i caus'd to be put under the bottom of the forementioned glass pipes two vessels , the one with fresh water , & the other with the like water impregnated with a good proportion of sea-salt that i had caus'd to be dissolv'd in it , for want of sea-water , which i would rather have imploy'd . and i found , that when the fresh water was rais'd to about inches , the saline solution had not fully reacht to . but though this difference were double to that which the proportion and gravity betwixt our sea-water and fresh water would have required , yet to make the disparity more evident , and also because i would be able the better to guess at the proportion of the dissolv'd salt by making it as great as i could , i caus'd an unusual brine to be made , by suffering sea-salt to deliquate in the moist air. and having applyed this liquor and fresh water to the two already mentioned pipes , and proceeded after the former manner , we found that when the pure water was elevated to near inches , the liquor of sea-salt wanted about . inches and a quarter of that height ; and when the water was made to subside to the middle of its pipe , or thereabouts , the saline liquor in the other pipe was between and inches lower then it . i would have tryed the difference between these liquors and oyl , but the coldness of the weather was unfavourable to such a tryal : but to shew a far greater disparity then that would have done betwixt the height of liquors of unequal gravities , i took fair water , and a liquor made of the salt of pot-ashes suffered to run in a sellar per deliquium , ( this being one of the ponderousest liquors i have prepar'd , ) and having proceeded as in the former tryals , i found that when the common water was about inches high , the newly mention'd solution wanted somewhat of inches ; and when the water was made to subside to the middle of its pipe , or thereabouts , the deliquated liquor was between and inches lower then it . i had some thoughts , when i applied my self to make these tryals , to examine how well we could by this new way compare the saltness of the waters of several seas , and those also of salt-springs ; and likewise whether , and ( if any thing near ) how far we might by this method determine the proportion of the more simple liquors that may be mingled in compounded ones , as in the mixture of water and wine , vinegar and water , &c. but being not provided with instruments fit for such nice tryals , and a mischance having impair'd the glasses lately mentioned before the last tryals were quite ended , and having soon after broken one of them , i laid aside those thoughts . experiment xiii . about the heights to which water and mercury may be rais'd , proportionably to their specifick gravities , by the spring of the air. in prosecution of the parallel formerly begun , betwixt the effects of the weight of the atmosphere , and the spring of included air , we thought fit after the foregoing to make the following experiment . we took a strong glass-bottle , capable to hold above a pint of water , and having in the bottom of it lodg'd a convenient quantity of mercury , we pour'd on it a greater quantity of water , ( because this liquor was to be impell'd up many times higher than the other , ) and having provided two slender glass-pipes , each open at both ends , we so plac'd and fastned them , by means of the cement wherewith we choak'd the upper part of the neck of the bottle , that the shorter of the pipes had its lower orifice immerst beneath the surface of the quick-silver , and the longer pipe reacht not quite so low as that surface , and so was immerst but in the water , by which contrivance we avoided the necessity of having two distinct vessels for our two stagnant liquors , which would have been inconvenient in regard of the slenderness of the upper part of our receiver . this done , we conveyed the bottle into a fitly shap'd receiver , ( formerly describ'd at the first experiment , ) and having begun to pump out the air , we took notice to what heights the quick-silver and water were impell'd up in their respective tubes , on which we had before made marks from inch to inch with hard wax , ( that they might not be remov'd by wet or rubbing , ) and we observ'd , that when the quicksilver was impell'd up to two inches , the water was rais'd to about eight and twenty ; and when the quick-silver was about one inch high , the water was about fourteen . i say , about , partly because some allowances must be made for the sinking of the superficies of the stagnant quicksilver , and the greater subsidence of that of the stagnant water , by reason of the liquors impell'd into the two pipes ; partly because that the breadth of the mark of wax was considerable , when the quick-silver was but about an inch high , and so made it difficult to discern the exact height of the metal , when the water was fallen down to fourteen inches : especially in regard that the quick-silver never ascending so high as the neck of the bottle , ( which the water left far beneath it , ) the thickness of the receiver , and that of so strong a bottle made it difficult to discern so clearly the station of the quick-silver as i could have wished . experiment xiv . about the heights answerable to their respective gravities , to which mercury and water will subside , upon the withdrawing of the spring of the air. for the further illustration of the doctrine propos'd in the last and some of the foregoing experiments , about the raising and sustentation of liquors in pipes by the pressure of the air ; i thought it not unfit to make the following tryal , though it were easie to foresee in this peculiar experiment a peculiar difficulty . we caus'd then to be convey'd into a fitly shap'd receiver two pipes of glass very uneven in length , but each of them seal'd at one end , the shorter tube was fill'd with mercury , and inverted into a small glass jarr , wherein a sufficient quantity of that liquor had been before lodg'd : the longer pipe was fill'd with common water , and inverted into a larger glass , wherein likewise a fit proportion of the same liquor had been put . then the receiver being closely cemented on to the engine , the air was pump'd out for a pretty while before the mercury began to subside ; but when it was so far withdrawn , that its pressure was no longer able to keep up a mercurial cylinder of that height , that liquid metal began to sink ; the water in the other tube , though this were three times as long , still retaining its full height . but when the quick-silver was fallen so low , as to be but between three & four inches above the surface of the stagnant quick-silver , the water also began to subside , but sooner then according to the laws of meer staticks it ought to have done , because many aerial particles emerging from the body of the water to the upper part of the glass , did by their spring concurr with the gravity of the water to depress this liquor . and so when the quick-silver was three inches above the stagnant mercury , the water in the other pipe was fallen divers inches beneath , and several inches beneath when the mercury had subsided an inch lower . but this being no more then was to be expected , after we had caus'd the pumping to be a while continued , to free the water the better from the latitant air , we let in the external air , and having thereby impell'd up again both the liquors into their pipes , and remov'd the receiver we took out those pipes , and inverting each of them again to let out the air , ( for even that wich held the quick-silver had got a small bubble , though inconsiderable in comparison of the air that had got up out of the water , ) we fill'd each of them with a little of the restagnant liquor belonging to it , and inverting each tube once more into its proper liquor , we repeated the experiment , and found it , as it seem'd , to require more pumping then before to make the liquors begin to subside ; so that when the mercury was fallen to three inches , or two , or one , the water subsided so near to the heights of , , or inches , that we saw no sufficient cause to hinder us from supposing , that the litle differences that appear'd between the several heights of the quick-silver , and fourteen times as great heights of the water ( which fell somewhat lower than its proportion in gravity required ) proceeded from some aerial corpuscles yet remaining , in spite of all we had done , in the water , and by their spring , though but faint , when once they had emerg'd to the upper part of the glass , furthering a little the depression of it : not now to mention lesser circumstances , particularly , that the surface of the stagnant water did not inconsiderably rise by the accession of the water lately in the pipe ; whereby the cylinder of water , rais'd above that surface , became by so much the shorter . however your lordship may , if you think fit , cause the experiment to be reiterated , which i could not so well do , by reason of a mischance that befell the receiver . experiment xv. about the greatest height to which water can be rais'd by attraction or sucking pumps . since the making and the writing of the foregoing experiments , having met with an opportunity to borrow a place somewhat convenient to make a tryal to what height water may be rais'd by pumping ; i thought not fit to neglect it . for though both by the consideration of our hypothesis , to whose truth so many phaenomena bear witness ; and though particularly by the consequences deduceable from the three last recited experiments i were kept from doubting what the event would be , yet i thought it worth while to make the tryal . i know what is said to have been the complaint of some pump-makers . but i confess the phaenomenon , 't was grounded on , seem'd not to me to be certainly enough deliver'd by a writer or two , that mention what they complain'd of ; and their observation seems not to have been made determinately or carefully enough for a matter of this moment . since that which they complain of seems to have been in general , that they could not by pumping raise water to what height they please , as the common opinion of philosophers about natures fuga vacui made them expect they might . and it may well have happen'd , that as they endeavoured onely to raise it to the height their occasions required , so all that their disappointment manifested , was , that they could not raise it to that particular height : which did not determine , whether if the pump had been a foot or a yard shorter , the water would then have been elevated to the upper part of it or no : but that which i chiefly consider is , that these being but tradesmen , that did not work according to the dictates of , or with design to satisfie , a philosophical curiosity , we may justly suspect , that their pumps were not sufficiently stanch , nor the operation critically enough perform'd and taken notice of . wherefore , partly because a tryal of such moment seem'd not to have yet been duely made by any ; and partly because the varying weight of the atmosphere was not ( that appears ) known , nor ( consequently ) taken into consideration by the ingenious monsieur paschal in his famous experiment , which yet is but analogous to this ; and partly because some very late as well as learned writers have not acquiesc'd in his experiment , but do adhere to the old doctrine of the schools , which would have water raiseable in pumps to any height , ob fugam vacut , ( as they speak , ) i thought fit to make the best shift i could to make the tryal , of which i now proceed to give your lordship an account . the place i borrowed for this purpose was a flat roof about foot high from the ground , and with railes along the edges of it . the tube we made use of should have been of glass , if we could have procured one long and strong enough . but that being exceeding difficult , especially for me , who was not near a glass-house , we were fain to cause a tin-man to make several pipes of above an inch bore , ( for of a great length 't was alleadg'd they could not be made slenderer , ) and as long as he could , of tin or laton , as they call thin plates of iron tinn'd over ; and these being very carefully soder'd together made up one pipe , of about one or two and thirty foot long , which being tied to a pole we tried with water whether it were stanch , and by the effluxions of that liquor finding where the leaks were , we caus'd them to be stopt with soder , and then for greater security the whole pipe , especially at the commissures , was diligently cas'd over with our close black cement , upon which plaister of paris was strewed to keep it from sticking to their hands or cloaths that should manage the pipe. at the upper part of which was very carefully fastned with the like cement a strong pipe of glass , of between and foot in length , that we might see what should happen at the top of the water . and to the upper part of this pipe was ( with cement , and by the means of a short elbow of tin ) very closely fastned another pipe of the same metal , consisting of two pieces , making a right angle with one another , whereof the upper part was parallel to the horizon , and the other , which was parallel to the glass-pipe , reacht down to the engine , which was plac'd on the flat roof , and was to be with good cement sollicitously fastned to the lower end of this descending part of the pipe , whose horizontal leg was supported by a piece of wood , nail'd to the above mentioned rails ; as the tube also was kept from overmuch shaking by a board , ( fasten'd to the same rails , ) and having a deep notch cut in it , for the tube to be inserted into . this apparatus being made , and the whole tube with its pole erected along the wall , and fastned with strings and other helps , and the descending pipe being carefully cemented on to the engine , there was plac'd under the bottom of the long tube a convenient vessel , whereinto so much water was poured , as reach'd a great way above the orifice of the pipe , and one was appointed to stand by to pour in more as need should require , that the vessel might be still kept competently full . after all this the pump was set on work , but when the water had been raised to a great height , and consequently had a great pressure against the sides of the tube , a small leak or two was either discovered or made , which without moving the tube we caus'd to be well stopt , by one that was sent up a ladder to apply store of cement where it was requisite . wherefore at length we were able after a pretty number of exuctions , to raise the water to the middle of the glass-pipe above mentioned , but not without great store of bubbles , ( made by the air formerly conceal'd in the pores of the water , and now emerging , ) which for a pretty while kept a kind of foam upon the surface of it , ( fresh ones continually succeeding those that broke . ) and finding the engine and tube as stanch as could be well expected , i thought it a fit season to trie what was the utmost height to which water could by suction be elevated ; and therefore though the pump seem'd to have been plyed enough already , yet for further satisfaction , when the water was within few inches of the top of the glass , i caus'd exuctions more to be nimbly made , to be sure that the water should be raised as high as by our pump it could be possibly . and having taken notice where the surface rested , and caus'd a piece of cement to be stuck near it , ( for we could not then come to reach it exactly , ) and descending to the ground where the stagnant water stood , we caus'd a string to be let down , with a weight hanging at the end of it , which we applied to a mark , that had been purposely made at that part of the ( metalline ) tube , which the superficies of the stagnant water had rested at , when the water was elevated to its full height : and the other end of the string being , by him that let it down , applied to that part of the glass , as near as he could guess , where the upper part of the water reacht , the weight was pull'd up ; and the length of the string , and ( consequently ) the height of the cylinder of water was measur'd , which amounted to foot , and about inches . which done , i return'd to my lodging , which was not far off , to look upon the baroscope , to be informed of the present weight of the atmosphere , which i found to be but moderate , the quick-silver standing at inches , and between and eights of an inch . this being taken notice of , it was not difficult to compare the success of the experiment with our hypothesis . for if we suppose the most received proportion in bulk between cylinders of quick-silver and of water of the same weight , namely that of to , the height of the water ought to have been foot and about two inches , which is about inches greater than we found it . but then your lordship may be pleased to remember , that i formerly noted ( before ever i made this experiment ) that i did not allow the proportion betwixt mercury and water ( at least such water as i made my tryals with ) to be altogether so great , and though in ordinary experiments we may with very litle inconvenience make use of that proportion to avoid fractions , yet in so tall a cylinder of water as ours was , the difference is too considerable to be neglected . if therefore in stead of making an inch of quick-silver equivalent to inches of water , we abate but a quarter of an inch , which is but a part of the height of the water , this abatement being repeated times and a quarter , will amount to inches , and above a quarter , which added to the former height of the water , namely foot and inches , will make up foot and above an inch ; so that the difference between the height of the mercury sustain'd by the weight of the atmosphere in the baroscope , and that of the water rais'd and sustain'd by the pressure of the same atmosphere in the long tube did not appear to differ more than an inch or two from the proportion they ought to have had , according to the difference of their specifick gravities . and though in our experiment the difference had been greater , provided it exceeded not or inches , it would not have been strange : partly , because of the difficulty of measuring all things so exactly in such an experiment , partly because as waters are not all of the same weight , so a little disparity of it in so long a cylinder may be considerable , and partly ( and perhaps chiefly ) because the air flying out of the bubbles , that rose out of so great a quantity of water , and breaking at the top of it , and so near that of the tube , might by its spring ( though but very weak ) assisting the weight of so much water , somewhat ( though not much ) hinder the utmost elevation of that liquor . but our experiment did not make it needful for me to insist on these considerations , and the inconsiderable difference that was betwixt the height of the water we found , and that which might have been wish'd , did rather countenance then at all difavour the thing to be made out by our experiment , since by no pumping we could raise the water quite so high ( though i confess it wanted but very little ) as the weight of the atmosphere was able to keep up a cylinder of mercury proportionable to it in height , and equivalent in weight : and yet i presume , your lordship will easily grant , that there was at least as much care used in this experiment , to keep the things imploy'd about it tight , as has been wont to be used by tradesmen in their pumps , where t is not so easie either to prevent a little insinuation of the air , or to discern it . t is not that i am sure , that even all our care would have kept the water for any long time at its full height ; but , that the air was sufficiently exhausted for our purpose , when we determin'd the height of the water , i was induc'd to conclude by these circumstances . . as well the construction of the engine , as the many ( formerly related ) experiments , that have been successfully tryed with it , shew that t is not like it should be inferiour in closeness to the great water-pumps , made by ordinary tradesmen : and particularly the xi . experiment foregoing , manifests , that by this pump quick-silver was rais'd to as great a height , as the atmosphere is able to support in the torricellian experiment . . the stanchness of the pipe appear'd by the diminution ( as to number ) of bubbles , that appear'd at the top of the water , and by their size too , for when there was a leak , ( though but so very small , that the water could not get out at it in the tube , ) it might usually be taken notice of by the attentive ear of him that stood to watch upon the ladder , erected by the side of the tube ; and the air that got in , did easily discover it self to the eye by large bubbles , manifestly differing from those that came from the aerial particles belonging to the water ; and if the leak were not so very small , the air that got in would suddenly lift up the water above it , and perhaps fill with it the descending pipe. . though there had been some imperceptible leak , yet that would not have hindred the success of the experiment for the main . for in leaks that have been but small , though manifest enough , we have often , by causing the pump to be ply'd less nimbly then it now was , been able to prosecute our tryals ; because the pump carried of still more air than could get in at a leak that was no greater . . and that litle or no ( intruding ) air was left in the upper part of our tube , was evident by those marks , whereby it was easie for them that are well acquainted with the pump , to estimate what air is left in the vessel it should exhaust , and particularly towards the end of our operation i observ'd , that when the sucker was deprest , there came out of the water that cover'd the pump , so very few bubbles , that they might be imputed to the air afforded by the bubbles , springing from the water in the tube ; whereas if any adventious air had got into that cylinder of water , it would have appear'd in the water that cover'd the pump . . lastly , it were very strange , that if the water was but casually hindred by some leak from ascending any higher , it should be so easy to raise it to the very number of feet that our hypothesis requires , and yet we should be unable by obstinate pumping to raise it one foot higher . note , . as soon as we had made our experiment , and thereby found , that what was requisite to it was in order ; i sent to give notice of it to d r wallis , and d r wren , as persons whose curiosity makes them as well delighted with such tryals , as their deep knowledg makes them most competent judges of them . but before they could be found , and come , it being grown somewhat late and windy , i that was not very well , and had tired my self with going up and down , could not stay with them so long as i intended , but leaving the rest of the repeated experiment to be shewn them by i. m. ( who had been very industrious in fitting and erecting the tube ) they and their learned friend ( whom they brought with them ) doctor millington , told me a while after , that they also had found the greatest height , to which they could raise the water , to be foot and an half . . when the water began first to appear in the glass , the bubbles would be , as i had foretold , exceeding numerous ; so as to make a froath of near a foot high , if the water were newly brought , and had never been rais'd in the tube before . but if the pumping were long continued , the number and height ( or at least one of the two ) of the aggregate of bubbles , would ( as there remain'd fewer and fewer aerial particles in the water ) be lesser and lesser ; but their emerging did never that i remember wholly cease . . at the beginning also there would appear great vibrations of the water in the upper part of the tube ; the rising and the falling amounting sometimes to a foot , or near half a yard : but these grew lesser and lesser , as those of the quicksilver in the torricellian experiment use to do . . one may use an ordinary pail to hold the stagnant water ; but we rather imploy'd a vessel of earth made ( for another purpose ) somewhat slender , and of a cylindrical shape , because in a narrow vessel t is more easie to guess by the rising and falling of the liquor , how the pump is ply'd , and to perceive even smaller leaks . . i must not forget to take notice , that though the newly nam'd gentlemen came to me ( when they had seen the experiment tryed ) within less than an hour after the time i had look'd upon the baroscope , and observ'd the quick-silver to stand somewhat beneath inches , and eights ; yet when presently upon their return i consulted the same instrument again , the mercury appear'd to be sensibly risen , being somewhat ( though but very litle ) above and inches , and eights , and or hours after ( at bed-time ) i found it to be yet more considerably risen . which may keep your lordship from wondring at what i intimated a little above , touching monsieur paschal's experiment , as well as touching the disappointment of the pump-makers endeavours . for t is not onely possible , that ( as i have elsewhere noted ) water may be raised in the same pump ( though we suppose it still equally stanch ) higher at one time than at another : but 't was contingent , that , in monsieur paschal's noble attempt to imitate the torricellian experiment with water in stead of quick-silver , the proportion betwixt the heights of those two liquors in their respective tubes answer'd so well to their specifick gravities . for , the varying weight of the atmosphere being not then ( that appears ) known , or consequently taken into consideration ; if monsieur paschal , having tryed the torricellian experiment , when the air was for instance very heavy , had tryed his own experiment , when the atmosphere had been as light as i have often enough observ'd it to be , he might have found his cylinder of water to have been half a yard or two foot shorter than the formerly measur'd height of the quick-silver would have required . i have now no more to adde about this th experiment , but that it may serve for a sufficient confirmation of what i note in another treatise , against those hydraulical & pneumatical writers , who pretend to teach wayes of making water pass by inflected pipes , and by the help of suction , from one side of a mountain to the other , be the mountain never so high . for , if the water be to ascend as 't were spontaneously above or foot , a sucking pump will not ordinarily , at least here in england , be able to raise it . and now i speak of mountains , it will not be altogether impertinent to add , that if it had not been for unseasonable weather , i had thought fit to make the foregoing th experiment ( of elevating mercury by suction ) to be tryed at the top of an hill , not far from the place i then was at . for by what has been already delivered , it appears , that we might have estimated the height , to which the water may be there elevated by suction , without repeating the experiment with a thirty five foot tube , ( which we could not hope for conveniency to do , ) by the utmost height to which our engine could have rais'd mercury : and it may be of some use to be able from experiments to make some estimate ( for it can scarce be an accurate one ) how much it may be expected , that pumps shall ( caeteris paribus ) loose of their power of elevating water by suction , by being imploy'd at the top of an hill , in stead of being so at the bottom , or on a plain . remembring always what i lately intimated , that even in the same place liquors will be brought to ascend by suction to a greater or less height at one time than another , according to the varying gravity of the atmosphere . experiment xvi . about the bending of a springy body in the exhausted receiver . the cause of the motion of restitution in bodies , and consequently of that which makes some of them springy , which far the greater part of them are not , has been ingeniously attempted by some modern corpuscularians , and especially cartesians ; but since divers learned and judicious men do still look upon the cause of elasticity , as a thing that needs to be yet farther enquired into ; and because i am not my self so well satisfied as to blame their curiosity , i held it not unfit to examine by the help of our engine their conjecture , who imagine that the air may have a great stroak in the making of bodies springy ; and this i the rather did , because i had * elswhere shewn , that there is no need to assert , that in all bodies , that have it , the elastical power flows immediately from the form , but that in divers of them it depends upon the mechanicanical structure of the body . to make some tryal therefore , whether the air have any great interest in the motion of restitution , we took a piece of whalebone of a convenient bigness and length , and having fasten'd one end of it in a hole made in a thick and heavy trencher , to be placed on the plate of the engine , we tyed to the other end a weight , whereby the whalebone was moderately bent , the weight reaching down so near to a body plac'd in a level position under it , that if the spring were but a little weaken'd , the weight must either lean upon , or at least touch the horizontal plain : or if on the other side the spring should grow sensibly stronger , it might be easily perceiv'd by the distance of the weight , which was so near the plain , that a litle increase of it must be visible . this done , we convey'd these things into the receiver , and order'd those that pump'd to shake it as litle as they could , that the weight might not knock against the body that lay under it , or so shake it , as to hinder us from discerning whether or no it were depress'd by the bare withdrawing of the air. and when the air had been well pump'd out , i watcht attentively whether any notable change in the distance of the weight from the almost contiguous plain would be produc'd upon its being let in again : for the weight was then at rest , and the returning air flowing in much more speedily than it could before be drawn out , i thought this the likeliest time to discover whether the absence of the air had sensibly altered the spring of the whalebone . but though the experiment were made more than once , i could satisfie my self onely in this , that the depression or elevation of the weight , that was due to the true and meer change of the spring , was not very considerable , since i did not think my self sure , that i perceiv'd any at all : for though it be true , that sometimes , when the receiver was well exhausted , the weight seem'd to be a little deprest , yet that i thought was very litle , if any thing more than what might be ascrib'd to the absence of the air , not consider'd as a body that had any thing to do directly with the spring , but as a body that had some ( though but a litle ) weight ; upon which account it made the medium , wherein the experiment was tried , contribute to support the weight that bent the spring ; which weight , when the air was absent , must ( being now in a lighter medium ) have its gravitation increas'd by as much weight , as a quantity of the exhausted air , equal to it in bulk , could amount to . but this experiment being tried only with vvhalebone , and in a receiver not very great , may deserve to be further tryed in taller glasses , with springs of other kinds , and by the motions of a vvatch , and other more artificial contrivances . experiment xvii . about the making of mercurial , and other gages , whereby to estimate how the receiver is exhausted . because the air being invisible , it is not always easie to know whether it be sufficiently pump'd out of the receiver that was to be exhausted ; we thought it would be very convenient to have some instrument within the receiver , that might serve for a gage , or standard ; whereby to judge whether or not it were sufficiently exhausted . to this purpose divers expedients were thought on , and some of them put in practise ; which , though not equally commodious , may yet all of them be usefully imploy'd , one on this occasion , and another on that . the first ( if i misremember not ) that i propos'd , was a bladder , ( which may be greater or less , according to the size of the vessel it is to serve for ) to be very strongly tied at the neck , after having had onely so much air left in the folds of it , as may serve to blow up the bladder to its full dimensions , when the receiver is very well exhausted , and not before . but though your lord-ship will hereafter find that i yet make use of small bladders on certain occasions , in which they are peculiarly convenient , yet in many cases they do , when the glasses are well exhausted , take up too much room in them , and hinder the objects , included in the receiver , from being observ'd from all the sides of it . another sort of gage was made with quick-silver , pour'd into a very short pipe , which was afterwards inverted into a litle glass of stagnant quick-silver , according to the manner of the torricellian experiment . for this pipe being but a very few inches long , the mercury in it would not begin to descend , till a very great proportion of air was pump'd out of the receiver ; because till then , the spring of the remaining air would be strong enough to be able to keep up so short a cylinder of mercury . and this kind of gage is no bad one . but because , to omit some other litle inconveniences , it cannot easily be suspended , ( which in divers experiments 't is fit the gage should be , ) and the mercury in it is apt to be too much shaken by the motion of the engine , there was another kind of gage by some ingenious man ( who ever he were ) substituted in its place , consisting of a kind of siphon , whose shorter leg hath belonging to it a large bubble of glass , most commonly made use of at an illustrious meeting of virtuosi ; where your lordship having seen it , i shall not need to describe it more particularly . but none of the gages i had formerly us'd , nor even this last , having the conveniences that some of my experiments require ; i was fain to devise another , which is that i most make use of , as having advantages , some or other of which each of the gages already mentioned wants ; for even that with spirit of wine , not to mention lesser disadvantages , hath a bubble too great to let it be useful in vessels so slender , as for some purposes i divers times imploy ; and this short cylinder of so light a liquor as spirit of wine , makes the subsidence of the liquor be indeed a good sign that the receiver is well exhausted , but gives us not an account what quantity of air may be in the receiver , 'till it be arriv'd at that great measure of rarefaction ; and the same liquor , being upon a very small leak ( such as would not be prejudicial to many experiments ) impell'd up to the top of the gage , we cannot afterwards by this instrument take any measure of the air that gets in at the leak . but now there are divers experiments where i desire to see the phaenomena that will happen , not onely ( or perhaps not at all ) upon the uttermost exhaustion of the air , but when the pressure of it is withdrawn to such or such a measure , and also when the air is gradually readmitted . to make the gage we are speaking of , take a very slender and cylindrical pipe of glass , of , , , or more inches in length , and not so big as a goose-quill , ( but such as we imploy for the stems of seal'd weather glasses , ) and having at the flame of a lamp melted it , but not too near the middle , to make of it by bending it a siphon , whose two legs are to be not onely parallel to one another , but as litle distant any where from one another as conveniently may be . in one ( which is usually the longer ) of these legs , there is to be left at the top , either half an inch , or a whole inch , or more or less than either , ( according to the length of the gage , or the scope of the experimenter ) of air in its natural state , neither rarefied , nor condens'd ; the rest of the longer leg , and as great a part of the shorter as shall be thought fit , being to be fill'd with quick-silver . this done , there may be marks plac'd at the outside of the longer ( or sealed ) leg , whereby to measure the expansion of the air included in the same leg , and these marks may be either litle glass knubs , about the bigness of pins heads , fasten'd by the help of a lamp at certain distances to the longer leg of the siphon , or else the divisions of an inch made on a list of paper , and pasted on either to the siphon it self , or to the slender frame , which on some occasions we fasten the gage to . this instrument being convey'd into a receiver , ( which for expedition sake we choose as small as will serve the turn , ) the air is to be very diligently pump'd out , and then notice is to be taken to what part of the gage the mercury is deprest , that we may know , when we shall afterwards see the mercury driven so far , that the receiver , the gage is plac'd in , is well exhausted . and if it be much desired to know more accurately ( for one may arrive pretty near the truth by guess ) what stations of the mercury in the gage are answerable to the degrees of the rarefaction of the air in the receiver ; that may be compassed either by calculation , ( which is not so easie , and supposes some hypotheses , ) or ( though not without some trouble ) by letting in the water as often as is necessary , into a receiver , whose intire capacity is first measured , and in which there may be marks made to shew when the water to be let in shall fill a fourth part , or half , or three quarters &c. of the cavity . for if ( for instance ) when the quick-silver in the gage is deprest to such a mark , you let in the water , and that liquor appears to fill a fourth part of the receiver , you may conclude , that about a th part of the air was pump'd out , or that a th part of the spring , that the whole included air had , was lost by the exhaustion , when the quick silver in the gage was at the mark above mentioned ; & if the admitted water do considerably either fall short of , or exceed the quantity you expected , you may the next time let in the water either after the mercury has a litle past the former mark , or a litle before it is arriv'd at it . and when once you have this way obtain'd one pretty long and accurate gage , you will not need to take so much pains to make others , since you may divide them by the help of that one ; for this being plac'd with any other in a small receiver , when the mercury in the standard-gage ( if i may so call it ) is deprest to any of the determinate divisions obtain'd by observation , you may thence conclude how much the air in the receiver is rarefied , and consequently by taking notice of the place where the mercury rests in the other gage , you may determine what degree of exhaustion in a receiver is denoted by that station of the mercury in this gage . perhaps i need not tell your lordship that the ground of this contrivance was , that whereas in divers other gages , when the pump came to be obstinately ply'd , the expansion of the included air would be so great , that it would either drive out the liquor , especially if it were light , or in part make an escape through it : i judg'd that in such an instrument , as that newly describ'd , those inconveniences would be avoided , because that the more the air should come to be dilated , the greater weight of quick-silver it would in the shorter leg have to raise , which would sufficiently hinder it from making that heavy liquor run over ; and the same ponderousness of the liquor , together with the slenderness of the pipe , would likewise hinder the included air from getting through in bubbles . nb. . for most experiments , where exact measures are not required , it will not be so necessary to mark the gage at any other station of the quick-silver then that which t is brought to by the exhaustion of the receiver , for by that alone we may know when the air is well pump'd out of the receiver , wherein the gage is included : and when one is a litle us'd to some particular gage , one may by the subsidence of the mercury guess at the degree of the airs rarefaction , so near as may serve the turn in such experiments . but when this instrument is to be us'd about nice tryals , where it may be thought requisite to have it divided according to one of the ways formerly proposed , it will on divers occasions be more secure ( in case the maker of the gage has skill to do it , ) to put to the divisions rather by litle knubs of glass , than by paper ; because this will on such occasions be in danger either to be rubb'd off , or wetted . and if glass-marks be us'd , it will be convenient that every fifth , or tenth , or such ordinal number as shall be judg'd fit , be made of glass of a differing colour , for distinction sake , & the more easie reckoning . we sometimes for a need apply , in stead of these glass-knubs , little marks of hard sealing wax , which will not be injur'd by moisture , as those papers will that are pasted on ; but these of wax , though in many cases useful , are not comparable to the other in all , since if they be very small , they are easily rubb'd off , and if large , they make not the division exact enough , and often hide the true place of the quick-silver . i shall here about the mercurial gages add onely this hint , that what i propos'd to my self in that contrivance , was not onely to estimate the air pump'd out of the receiver , or that remaining in it ; but also , by the help of this instrument ( as elsewhere by another experiment ) to measure ( somewhat near ) the strength of the spring of rarefied air , according to its several degrees of rarefaction ; and by this observation , in concurrence with other things , i hoped we might ( according to what i have elsewhere insinuated ) be assisted to estimate , by the cylinder of mercury rais'd in the open leg , the expansion of the air included in the sealed leg : but of these things i design'd in this place to give but an intimation . . that leg of the gage that includes the air , may be seal'd up either at the beginning , before the pipe be bent into a syphon , or ( which is much better ) after the following manner . before you bend the pipe , draw out the end of it , which you mean to seal , to a short and very slender thread ; then having made the pipe a siphon , pour into the leg , which is to remain open , as much quick-silver as you shall judg convenient , which will rise to an equal height in the other leg ; out of which by gently inclining the siphon , you may pour out the superfluous mercury , ( if there be any , ) and when you see that there is an inch , or half an inch ( or what part you design'd to leave for air ) unfill'd with mercury , next to the end that is to be clos'd ; and that the rest of that leg , and as much ( as you think fit ) of the other is full of quick-silver , you may , by keeping the siphon in the same posture , and warily applying the slender apex above mentioned to the upper part of the flame of a lamp , blown horizontal , easily seal up that apex without cracking , or prejudicing the open leg , or considerably injuring the air hole , that was to be seal'd up in the other . and this sealing of one leg must ( as t is evident ) keep the mercury suspended in it , though it be higher by divers inches than that in the open leg , till the withdrawing of the external air enable the included , by expanding it self to depress the mercury in the seal'd leg , and raise it in the open . . how the length of these mercurial gages is to be varied , according to the bigness and shape of the slender receivers they are to be imploy'd in , and how they may easily be made either to stand upright at the bottom of the receiver , or be kept hanging in the middle , or near the top of it ( as occasion may require , ) and how the open end may be made to secure the mercury , in cases where that is needful , belongs not so properly to this treatise , as to the second part of the continuation ; where , if ever i trouble your lordship with it , the usefulness of this sort of gages , and the circumstances that may advantage them , will best appear . . there being some experiments , wherein it is not desir'd that the receiver should be neer exhausted , but rather that the degrees of the airs rarefaction , which ought not to be very great , should be well measur'd ; we may in such cases make use of gages shap'd like those hitherto describ'd , but made as long as the receiver will well admit , and furnish'd in stead of quick-silver either with spirit of wine coloured with cocheneel , or else with the tincture of red rose-leaves , drawn onely with common water , made shap by a litle either of the oyl , or the spirit of vitriol , or of common salt. for the lightness of these liquors in comparison of quick-silver will allow the expansins of the air included in the gage to be very manifest , and notable enough , though not half , or perhaps a quarter of the air be pump'd out of the receiver . . you may also in such cases as these , where the receiver is large enough , and is not to be quite exhausted , make use of a mercurial gage , differing from those above describ'd onely in this , that the shorter leg need not be above an inch , or half an inch long , before it expand it self into a bubble of about half an inch , or an inch in diameter ; and having at the upper part a very short and slender unseal'd pipe , at which the air may get in and out : by which contrivance you may have this convenience , that you need not include so much air , as otherwise would be requisite , at the top of the longer leg , because the mercury in the shorter cannot , by reason of the breadth of the bubble , whereinto the expansion of the air drives it , be considerably rais'd : upon which account it becomes more easie to estimate by the eye the degrees of the included airs rarefaction , which may be done almost as easily , as if there were water in stead of mercury : provided it be remembred , that quick-silver by reason of its ponderousness , does far more assist the dilatation of the air , then so much water would do . experiment xviii . about an easie way to make the pressure of the air sensible to the touch of those that doubt of it . though several of our experiments sufficiently manifest to the skilful , that the pressure of the air is very considerable ; yet because some of them require peculiar glasses , and other instruments , which are not always at hand , and because there are many that think it surer to estimate the force of pressure by what they immediately feel , than by any other way ; i was invited for the sake of such to imploy an easie experiment , which usually proved convincing , because it operated on that sense , whereon they chiefly rely'd . i caus'd then to be made a hollow ( but strong ) piece of brass , not above two or three inches high , ( that it might be in a trice exhausted , ) and open at both ends , whose orifices were circular and parallel , but not equal , ( the instrument being made tapering , so that it might be represented by an excavated conus truncatus , or a gigg , with the lower part cut transversly off . ) this piece of brass being cemented on , as if it were a small receiver to the engine , the person , that would not believe the pressure of the air to be near so considerable as was represented , was bidden to lay the palm of his hand upon the upper orifice ; and being ordered to lean a little upon it , that so the lower part of his hand might prove a close cover to the orifice , one exuction of the air was made by the help of the pump : and then upon the withdrawing of the greatest part of the pressure of the internal air , that before counterballanc'd that of the external , the hand being left alone to support the weight of the ambient air , would be pressed inwards so forceably , that though the stronger sort of men were able ( though not without much adoe ) to take off their hands , yet the weaker sort of tryers could not do it , ( especially if by a second suck the litle receiver were better exhausted , ) but were fain to stay for the return of the air into the receiver to assist them . this experiment being design'd rather to convince than to punish those that were to make it , we took care not onely that the brass should be so thick , and the orifices so smooth , that no sharpness nor roughness of the metal should offend the hand ; but also that the narrower orifice ( which was the oftenest made use of ) should be but about an inch and a quarter in diameter . but if any were desirous of a more sensible conviction , 't was very easie to give it him by making the larger orifice the uppermost , which was the reason why the instrument was , as we formerly noted , made tapering . but yet this larger orifice ought not to exceed inches , or inches and / in wideness , least the great weight of the air endanger the breaking or considerably hurting the hand of the experimenter . which caution i am put in mind of giving , by remembring that i once much endangered my own hand , through the mistake of him that manag'd the pump , who unawares to me set it on work , when , for another purpose , i had laid my hand upon the orifice of an instrument of too great a diameter . the famous experiment of torricellius , mentioned in the th of our already published tryals , is of that noblenesse and importance , that though divers learned men have ( but upon very differing principles ) discours'd of it in print , which gives me the lesse mind to insist long upon it here , yet i shall not scruple to subjoin some notes concerning tryals that i made , ( though for want of opportunity i could not repeat them according to my custom , ) which i had not met with in others , and which may serve to confirm the hypothesis made use of in this continuation , and the treatise it belongs to . experiment xix . about the subsidence of mercury in the tube of the torricellian experiment to the level of the stagnant mercury . a baroscope being included in a receiver , made of a long bolt head with the lower part of the ball cut circularly off , upon the first exuction of the air , the quick-silver that before stood at inches , ( the atmosphere appearing then by a constant baroscope very light , ) would fall so low as to rest at or inches , ( for once i measur'd the subsidence beneath its former elevation , ) and in about three sucks more it would be brought quite down to the level of the stagnant quick-silver , and somewhat below , ( as t is the property of quick-silver , quite contrary to water , to rise less in a slender pipe than in a wide . ) the air being let into the receiver , the quick-silver would be impell'd up slowlier or faster , as we pleas'd , to the former height of inches , or thereabouts . nb. . that if the air were suffer'd to go hastily out of the receiver , the mercury would , by virtue of the accelerated motion acquir'd in its descent , at the very first suck descend till it reacht within an inch or two of the stagnant mercury , though it would presently after a few risings and fallings settle at the height of or inches , till the next suck brought it down lower . . if when the mercury was reimpell'd up to its due height , those that manag'd the pump did , in stead of rarifying the air , a little compress it , the quick-silver would by the compress'd air be easily made to rise an inch or more above the former standard of inches . which circumstance i mention , not as a new thing , but to confirm ( what some think strange ) a passage printed , page the th , where i mention , that if the air in the receiver , in stead of being rarify'd in the engine , were a litle comprest by it ; the pressure of the included air , being somewhat increas'd by having its spring thus bent , would sustain the mercury in the torricellian tube at a greater than the wonted height . and to confirm another passage in the same page , where i observ'd , that if the pressure of the air upon the stagnant mercury be not so great as t is wont to be , the mercury will begin to subside in a ( fill'd and inverted ) tube , which wants of the usual height ; we took a glass cane , ( seal'd at one end , ) much shorter than the due length , and having fill'd it with mercury , and inverted it into a glass full of stagnant mercury , we placed all in the former receiver ; where the mercurial cylinder for want of the requisite height remain'd totally suspended , but upon the first or second suck it would subside , and in two or three sucks more it would fall to the levell of the stagnant mercury , or a little below it . upon the letting in of the air it would be impell'd to the very top of the tube , bating an aerial bubble , which seem'd to come from the mercury it self , and was so little , as not to be at all discernable , save to a very attentive eye . this experiment i should not think fit here to relate , since i formerly acquainted your lordship with the subsidence of the mercury upon the withdrawing of the air from the receiver , were it not that , in the mention of that tryal , i remember i confess'd to you , that i could not so free the great receiver i then us'd from air , but that the litle that remained or leak'd in , made me unable to bring the mercury in the tube totally to subside , or fall much nearer than within an inch of the surface of the stagnant mercury , with which in our present tryals that in the tube was brought to a level . experiment xx. shewing that in tubes open at both ends , when no fuga vacui can be pretended , the weight of water will raise quick-silver no higher in slender than in larger pipes . because i find it , even by learned and very late writers , urg'd as a clear and cogent argument against those that ascribe the phaenomena of the torricellian experiment to the weight of the external air ; that t is impossible , that the air , though 't were granted to be a heavy body , could sustain the quick-silver at the same height in tubes of very differing bigness , since the same air cannot equally counterpoise mercurial cylinders of such unequal weights ; and because this objection is wont very much to puzzle those that are not well acquainted with the hydrostaticks , i presume your lordship will allow me , till i can shew you some hydrostatical papers , by which the objection may appear to be but ill grounded upon the true theoremes of that art , to annex the transcripts of a couple of expeperiments , ( that i once made to remove this , supposedly insuperable , difficulty , ) just as i find them registred in my note-books . the i. tryal . sept. the . . we took a very large glass-tube , hermetically seal'd at one end , and about two foot and a half in length . into this we poured quick-silver to the height of or fingers . then we took a couple of cylindrical pipes of very unequal sizes , ( the wider being as big agen as the slenderer ) and open at both ends. the lower ends of these two pipes we thrust into the quick-silver , and fasten'd them near their upper ends to the tube with strings , that they might not be lifted up , nor mov'd out of their posture , in which the convex surface of the mercury in both the pipes seem'd to lie almost in a level , the tube also it self being plac'd upright in a frame . this done , by the help of a funnel we poured in water by degrees at the top of the tube , and observ'd , that as the water gravitated more and more upon the stagnant mercury , so the included mercury rose equally in both the pipes , till the tube being almost fill'd with water , the mercury appeared to be impell'd up to and sustain'd at as great a height in the big tube , as in the lesser , being in either raised about two inches above the surface of the stagnant quick-silver . nb. . having caus'd about half the water ( having no conveniency to withdraw any more ) in the tube to be suck'd out at the top , we observ'd the quick-silver in both the tubes to subside uniformly , and to reascend alike upon the reaffusion of the water . . we endeavoured to try the experiment ( for their sake who have not the conveniency to have such tubes purposely made ) in a wooden vessel , into which , when it was fill'd with water , we let down a flat glass furnisht with stagnant mercury , whereinto the ends of the two pipes were immers'd . but the opaeousness of the cylinder ( which reduced us to see onely from the top the reflection of the stagnant mercury , ) and other impediments , disabled us to perceive the motions and stations of the mercury in the pipes , though we once made use of a candle the better to discern them . the ii. tryal . we took a very wide tube of glass , of about a foot long , and into it poured a convenient quantity of quick-silver . we took also two pipes of about equal length , and of that disparity in bigness that we newly mentioned , ( those pipes lately described being indeed cut off from these we are now to speak of , ) and these being fill'd with quick-silver ( after the manner of the torricellian experiment ) were by a certain contrivance let down into the tube , and unstopt under the surface of the stagnant mercury , and then the quick-silver in the pipes falling down to its wonted station , and resting there , we poured into the tube about a foot height ( by guess ) of water , whereupon the quick-silver as it before stood , as it were , in a level in both the pipes , so it was , for ought appear'd to us , equally impell'd up beyond its wonted station , and sustain'd there both in the slender and in the bigger pipe , and upon the withdrawing of some of the water it began to subside alike , as to sense , in them both , falling no lower in the bigger than in the slenderer . and water being a second time poured down into the tube , the mercury did in both pipes rise uniformly as before . by which and the former experiment it sufficiently appeared , that a gravitating liquor as air or water , may impell or keep up mercury to the same height in tubes that are of very differing capacities : and that liquors ballance each other according to their altitude , and not barely according to their weight . for in this last experiment , the additional cylinder of one inch of mercury was manifestly rais'd and kept up by the water incumbent on the stagnant mercury , ( the other cause , whatever it were , of the mercury's suspension , being able to sustain but a cylinder shorter by an inch. ) and the same parcel of water did counterpoise in the differing pipes two mercurial cylinders , which though but of the same altitude , ( namely about an inch ) were of very unequal weight . experiment xxi . of the heights at which pure mercury , and mercury amalgam'd with tin , will stand in barometers . considering with my self , that if the sustentation of the quick-silver in the torricellian experiment at a certain height , depends upon the aequilibrium , which a liquor of that specifick gravity does at such a height attain to with the external air , if that peculiar and determinate gravity of the quick-silver be altered , the height of it , requisite to an aequilibrium with the atmosphere , must be altered too : ( considering this i say ) i thought it might somewhat confirm the hypothesis hitherto made use of , if a phaenomenon so agreeable to it were actually exhibited . this i supposed performable two differing wayes , namely by mixing or ( as chymists speak ) amalgamating mercury either with gold , to make it a mixture more heavy , or with some other metal that might make it more light than mercury alone is . but the former of those two ways i forbore to prosecute being where i then was unfurnished with a sufficient quantity of refined gold , ( for that which is coyn'd is generally allayed with silver , or copper , or both , ) and therefore amalgamating mercury with a convenient proportion of pure tin , ( or , as the tradesmen call it , block-tin , ) that the mixture might not be too thick to be readily poured out into a glass-tube , and to subside in it , we fill'd with this amalgam a cylindrical pipe , sealed at one end , and of a fit length , and then inverted it into a litle glass furnished with the like mixture . of which tryal the event was , that the amalgam did not fall down to , nor even to inches , but stopt at above the surface of the stagnant mixture . note . that though one may expect , that the event of the experiment would be the more considerable , the greater the quantity is that is mingled of the light metal , yet care must be taken that the amalgam be not made too thick , least part of it stick here and there ( as we did to our trouble find it apt to do ) to the inside of the pipe , by which means some aerial corpuscles will meet with such convenient receptacles , as to make it very difficult , if not almost impossible , to free the tube quite from air. . it may perhaps be worth while to try , whether by comparing the height of the amalgam , to what it ought to be upon the score of the specifick gravities of the mercury , and the tin , mingled in a known proportion in the amalgam , any discovery may be made whether those two metals do penetrate one another after such a manner ( for there is no strict penetration of dimensions among bodies ) as copper and tin have , as i elsewhere note , been ( by some chymists ) observ'd to do , when being melted down together they make up a more close and specifically ponderous body , than their respective weights seem'd to require . . that by comparing this . experiment with the th of those formerly published , it may appear , that the height of the liquor , suspended in the torricellian experiment , depends so much upon its aequilibrium with the outward air , that it may be varied by a change of gravity in either of the two bodies that counterballance each other , whether the change be of weight in the atmosphere , or of specifick gravity in the suspended liquor . advertisement . i should here acquaint your lordship with what i have since tried in reference to the th of the printed experiments , where i mention , that i observed , by long keeping the same instrument with which i once made the torricellian experiment in the same place , that the height of the suspended mercury would vary according as the weight of the atmosphere hapned to change . but though about the barometer ( as others have by their imitation allowed me to call the instrument hitherto mentioned , put into a frame ) i made in the year several observations , that would not perhaps be impertinent in this place , yet having long since left them with a friend , who lives far off , and not having them now in my power , i must beg your lordships permission to reserve them for a part of the appendix , which i doubt i shall be engaged to adde to this epistle . and in the mean time i shall not forbear to present your lordship those other papers that i have by me , relating to the barometer ; some of which will , i presume , sufficiently confirm my lately mentioned conjecture about the cause of the variation observed in the height of the suspended mercury . experiment xxii . wherein is propos'd a way of making barometers , that may be transported even to distant countries . thinking it a desireable thing ( as i have elsewhere intimated ) to be able to compare together , by the help of barometers , the weight of the atmosphere at the same time , not onely in differing parts of the same country , as of england , but in differing regions of the world ; i could not but foresee that 't would be very difficult to accomplish my desire without altering the form of the barometers i had hitherto made use of . for as these be unfit to be transported far , because that stagnant mercury would be so apt to spill . so the procuring them to be made in the places where they are to be used , though it be no bad expedient , and such as i have divers times made use of , is liable to this inconvenience ; that , besides that few will take the pains , and have the skill , requisite to make baroscopes well , though they be sufficiently furnished with glasses and mercury for that purpose , besides this , i say , except men be more than ordinarily diligent and skilful , ( and perhaps though they be , ) 't will be very difficult to be sure that the baroscope newly made in a remote country , is as good ( and but as good ) as that which a man makes use of in this ; in regard that at the making of the former , they are supposed to have no other baroscope to compare it with ; and to be sure , they have not the same with which it is to be compared here. being by these considerations invited to attempt the making of portable or travailing baroscopes , ( if i may so call them , ) i thought it requisite to endeavour these three things : the first , to make the vessel that should contain both the sustained and the stagnant mercury all of one piece of glass , of a like bigness : the next , to place this vessel , when fill'd , in such a frame , as may be easie to be transported , and yet in a reasonable measure defend the glass from external violence , no part of it standing quite out of the frame , as in all other baroscopes : and the third , so to order the vessel , that it may not be subject to be easily broken by the violent motion of the mercury contain'd in it . the first of these will not seem practicable to those that imagine ( without any warrant from the hydrostaticks ) that t is as well necessary as usual , that the stagnant mercury should have a vessel much wider than the tube , wherein the mercurial cylinder is sustain'd ; but to us the difficulty seem'd much less to make the glass part of our tube of one piece , and of a convenient shape , than afterwards to fill it . but to do both , we took a glass cylinder seal'd at one end , and of a convenient length , ( as about or foot , ) and caus'd it by the flame of a lamp to be so bent , that , to those that did not take notice 't was sealed at one end , it seem'd to be a syphon of very unequal legs , the one being or times longer than the other ; by virtue of which figure the shorter leg may serve in stead of the distinct vessel usually imployed to contain the stagnant mercury . to fill this , which is not easie , one may proceed after this manner . take a small funnel of glass , with a long and slender shank , so that it may reach or inches , or further , into the shorter leg of our barometrical syphon ( if i may so call it ; ) and by this funnel pour into this shorter leg as much mercury as may reach about or inches in both legs ; then stopping the orifice with your finger , and slowly inclining the tube , the mercury in the longer leg will gently fall to the sealed end ; and the air that was there before , will pass by it , and so make it room . the mercury in the shorter leg ( which leg ought to be held uppermost ) will by the same inclination of the tube fall towards the orifice , but , being by the finger that stops that , kept from falling out , if you do slowly reerect the glass , and then make it stoop again as much as before , the mercury will pass out of the shorter leg into the longer , and joyn with that which was there before ; and if all the mercury do not so pass , the orifice is to be stopt again with your finger , and the tube inclin'd as formerly . this done , the tube is to be erected , and by the help of the funnel more mercury is to be poured in , and the foregoing process of stopping the orifice , inclining the tube &c. is to be repeated , till all the mercury pour'd into the shorter leg , be brought to joyn with that in the longer ; and then the open leg is to be furnisht with fresh mercury , observing this , that the nearer the longer leg comes to the being fill'd , the less you must raise it from time to time , when you pour mercury into the shorter ; as also , that when you see the longer leg quite full of mercury , ( though there be but litle in the shorter , ) you need not pour in any more , if the longer do much exceed a yard ; because upon the restoring of the tube to an erected posture there will subside from the taller leg into the other a pretty quantity of mercury , by reason of the space at the seal'd end , which will be deserted by the mercury that was there . but because t is difficult by this way , as well as by that practised already , to fill a tube with mercury without leaving any visible bubbles ; to free it from such ( if any happen to be ) you must once more stop the orifice with your finger , and incline , and reerect the tube divers times , till you have thereby brought most of the smaller bubbles into one greater ; ( which you may if you please increase , by letting in a little air : ) for by making this great bubblle pass leisurely two or three times from one end of the tube to the other , it will in its passage as it were lick up all the small bubbles , and unite them to its self ; which may afterwards by one inclination more of the tube be made to pass into the shorter leg , and thence into the free air. but there is another sort of funnels , which if one have the skill and conveniency to make , ( as i. m. easily doth , ) one may very expeditiously fill the bended tubes of our portable barometers . for if you make the slender part of the funnel not streight but bended , in the form of an obtuse angle , and of such a length , that the part which is to go into the shorter leg of our siphon may reach to the flexure ( of the siphon ; ) then you may , by so holding the tube that the sealed end be somewhat lower than the other , and by pouring in mercury at the obtuse end of the angular funnel , easily make it run over the flexure into the longer leg of the siphon ; provided you do now and then , as occasion requires , erect a litle and shake the tube , to help the mercury to get by the air , and expell it . by such wayes as these we have found by experience , that t is possible ( though not easie ) to do in such a bended glass , as our purpose requires , what , besides a very late learned writer , the diligent mersennus himself , admonishes his reader , that t is not a practicable thing to do in the ordinary glasses of the torricellian experiment , viz. to free the mercury of a straight tube from air and bubbles , ( s as to be able by inclining the glass to make the liquor ascend to the very top . ) the first of our above mentioned scopes being thus attained , it was not difficult to compass the second , by the help of a solid piece of wood , which is to be somewhat longer than the tube , and a good deal broader in the lower part than in the upper , that it may receive the shorter leg of the siphon . in such a piece of wood , which was about an inch thick , we caus'd to be made a gutter or channel , of such a depth and shape , that our siphon might be placed in it so deep , that a flat piece of wood ( like a plain'd lath ) might be layd upon it , without at all pressing upon or so much as touching the glass ; so that this piece of wood may serve for a cover to defend the glass , to be put on when the instrument is to be transported , and taken off again when t is to be hung up to make observations with ; the channel-piece of wood serving both for a part of a case , and for an entire frame ; which may for some uses be a litle more commodious , if the cover be joyned ( as it may easily be ) to the rest of the frame , by or litle hinges and a hasp , by whose help the case may be readily opened and shut at pleasure . the d thing we proposed to our selves is nothing near so easie as the d , nor have we yet had opportunity to try , whether the way we made use of will hold , if the barometer be transported into very remote parts , though by smaller removes we found cause to hope that 't will succeed in greater . the grand difficulty to be obviated was this ; that though 't were easie to hinder the spilling of the mercury , by stopping the orifice of the shorter leg of our siphon , yet that would not serve the turn ; for the upper part of the tube being destitute of air , if the mercury be by the motion of the instrument put to vibrate , it will be apt ( for want of meeting with any air in the upper part of the tube to check its motions ) to hit so violently against the top of the glass as to beat it out , or to crack some of the neighbouring parts . to obviate this great inconvenience our way is , to incline the tube , till the mercury be impell'd to the very top of it , and yet there will remain a competent quantity in the shorter leg of the glass , if that be not at first made too short . this done , the remaining part of the shorter leg is to be quite fill'd up either with water or mercury , and the orifice of it is to be very carefully and firmly stopt , ( for which purpose we use our strong black cement : ) for by this means the mercury in the longer leg , having no room to play , cannot strike with violence as before , against the top of the glass . but though by many times successively shaking the baroscope we did not perceive that 't was very like to be prejudiced by the shakes it must necessarily indure in transportation to remote places , if due care be had of it by the way , yet till further tryal have been made i shall not pretend to be certain of the event . but thus much of conveniency we have already found in this contrivance , that we sent it some miles off to the top of a hill , and had it brought home safe again , the phaenomena at the top and bottom of the hill being answerable to what we might have expected if we had imployed another baroscope . when the instrument is to be sent away , the height of the mercurial cylinder ( to be measured from the surface of the stagnant mercury in the shorter leg ) being taken for that place , day , and hour , and compar'd ( if it may be ) with that of another good baroscope , which is to continue in that place ; as much of the gutter as is unfill'd by the glass may be well stuffed with cotten , or some such thing , to keep the glass the more firm in its posture ; and that the tube be not shaken or press'd against the wood , some of the same matter may be put between the rest of the frame and the cover , which ought to be well bound together . and when the instrument is arriv'd at the remote place where t is to be imployed , ( for if it be to be sent but a litle way , it may be carried safely without using any adventitious liquor , ) the water that is added , may be taken off again , by soaking it up with pieces of sponge , linnen , &c. but if in stead of water you put in mercury , as it ought to have been put in by weight , so it is to be taken out , till you have just the weight that was put in : and t is not difficult to take out the mercury by degrees , by the help of a small glass-pipe , since you may either suck up litle by little as much as remains of the additional mercury , when by erecting the barometer , and warily unstopping the orifice of the lower leg , as much mercury as will of its self flow out is efflux'd ; or else you may take out the superfluous mercury , by thrusting the lower end of the litle pipe into that liquor , and when it has taken in enough , stopping the upper end close with your finger , to keep it from falling back again when you remove the pipe. nb. if it should happen in a long voyage , that by the numerous shakings of the instrument there should from the additional water or mercury in the shorter leg get up into the longer any litle aerial bubble , which seems the onely ( but i hope not likely ) danger in this contrivance , he that is to use the instrument , at the end of the voyage may , if he be skilful , free the mercury from it by the same way , that we lately prescrib'd to free it from air , when the instrument was first fill'd . i presume i need not tell your lordship , that the chief use of this travailing baroscope is , that he that uses it in a remote part , keeping a diary of the heights of the mercury , by comparing these heights with those at which the mercury stood at the same times in the barometer that was not remov'd , the agreement or difference of the weight of the atmosphere in distant places may be observed . to which this may be added , the conveniency , which the structure of these instruments gives them to be securely let down into deep wels or mines , and to be drawn up to the top of towers and steeples , and other elevated places : not here to consider , whether by a convenient addition , these , as well as some other barometers , may not be made to discover even very minute alterations of the atmospheres pressure . whether this travailing baroscope , being furnish'd at its upper end with a very good ball and socket , and at the lower end with a great weight , ( which way of keeping things steady in a ship has been happily used by the royal society on another occasion , ) whether , i say , our instrument may by this contrivance , or some other that might be suggested to the same purpose , be made any thing serviceable at sea , notwithstanding the differing motions of the ship , i have had no opportunity to try : but whether it may or may not be useful in spite of the rolling of the ship , it may at least be made use of in flat calms , ( which divers times happen in long voyages , especially to the east-indies , and to africk , ) and then the instrument , which at other times may lie by without being at all cumbersom , may be made use of , as long as the calm lasts , to acquaint the observer with the weight of the atmosphere in the climate where he is , and that upon the sea : which may give some welcome information to the curiosity of speculative naturalists , and perhaps prove either more directly or in its consequences of some use to navigators themselves , as by enabling them by its suddain changes to foretell the end of the calme . besides that , having one of these instruments ready at hand , where ever they set foot on shore , though it be but upon a small island , or a rock , they can presently and easily take notice of the gravity of the atmosphere in that place ; which whether or no , if compared with other observations , it may in time prove not altogether useless to the guessing whereabouts they are , and the foreseeing some aproaching changes of weather , i leave to future experience , if it shall be thought worth the making , to determine . besides the ordinary baroscope , and this travailing one , i have imployed or other instruments of quite differing kinds , to discover the varying gravities of the atmosphere ; but though they have hitherto succeeded well ( for the main , ) yet being willing to make further observations about them , i reserve one of them for another opportunity , and think fit to leave the other in a tract it belongs to . a post-script advertisment . since the writing of the foregoing and the following experiments about the travailing baroscope , having had occasion to make one at a place about miles distant from that where i was when i writ them , i took notice , that the mercury in the travailing baroscope was not by / of an inch so high as that in another baroscope made the ordinary way ; and yet 't was not easie to perceive , that the former had been less carefully fill'd than the latter . so that i yet know not well to what cause to impute the difference , unless it should perhaps depend upon this circumstance ; that the pipe , whereof the travailing baroscope was made , was very slender , and much more so than the tube of the other ; and i have already elsewhere observed , that mercury , contrary to what happens in water , is lesse apt to rise in very slender pipes . and though i remember that , at the place where i writ the experiment , to which this postscript belongs , in the tube i then imployed to make the travailing baroscope , the mercury ascended as high as in a noted one made the common way , yet not being in the other place furnished with a tube long and big enough , i think my self oblig'd , till i can clear the doubt by further tryal , to give your lordship this advertisement , lest either the cause already suspected , or some other unheeded thing may in some cases make these travailing baroscopes somewhat differing from others . but though they should prove to be so , yet it would not follow that they cannot be made serviceable : for keeping a pretty while that instrument , which suggested the scruple to me , just by the other with which i had compar'd it , and carefully taking notice of the respective heights at which the mercury rested in both , i observ'd that when it rose or fell in the other barometer , it did also rise and fall in the portable one ; and when it rested at its first station in the fromer , it did so in the later ; and though there seem'd to be an inequality in the quantity of the ascent , and subsidence of the mercury in the two instruments , yet that seem'd to be accountable for by some circumstances , especially the very unequal breadth of the vessel that contain'd the stagnant mercury in the other barometer , and that shorter leg which answer'd to that vessel in the travailing barometer . but till the formerly proposed scruple be by further observation removed , the safest way will be to make the barometer to be sent to remote places , as like as may be ( in highness , and length of the tube ) to another portable one kept at home ; that so when they are once adjusted , the collations may be made betwixt two instruments of the same kind , whereof that which is kept at home may also , if it be thought fit , be compared , when the observations are made , with a baroscope made the ordinary way . experiment xxiii . confirming , that mercury in a barometer will be kept suspended higher at the top , than at the bottom of a hill. on which occasion something is noted about the height of mountains , especially the pic of tenariff . to give your lordship some instance ( till i can present you with a nobler one ) of the use of our travailing barometer , i shall now adde : that when i writ the foregoing experiment , chancing to be within or miles of a hill , which , though not high , was the least low in that countrey , i thought our instrument might be sfely , and not altogether uselesly , carried on horse-back to the top of it , which was too remote from the bottom to be conveniently reacht by me on foot in the midst of winter . this tryal therefore i resolv'd to make , because , though i formerly told you of a considerable one that had been made in france by some eminent virtuosi of the country , yet i was willing , not onely to have a proof how safely our baroscope might be transported , but to confirm to your lordship upon our own observation , made in another region , so considerable an argument , as these kind of experiments afford to our hypothesis : and though when i came to try the experiment , i hapned to have an indisposition that forbid me to do it all my self , yet having carefully mark'd on the edge of the frame the height to which the suspended quick-silver reach'd , and compar'd it with a good baroscope made the ordinary way , i commmitted our instrument to a couple of servants , that i had often imployed about pneumatical and mercurial experiments , giving them particular instructions what to do . and the instrument being such as might be safely carried on horseback , i had in two or three hours an account brought me back , the summe of which was : that they found the suspended mercury fall a litle as they ascended the hill , at whose top they gave the liquor leave to setle , and carefully took notice by a mark of the place it rested at ; which was ; as i afterwards found , ¼ of an inch , or somewhat better beneath the mark i had made , and this notwithstanding the hill was not high , and the air and wind seem'd to them to be much colder at the top of it , than beneath . but though , as they descended more and more , they observ'd the mercury to rise again higher and higher , ( as being press'd against by a taller column of the atmosphere , ) and though consequently the experiment agreed very well with our hypothesis , and may serve for a confirmation of it ; yet by reason of the small height of the mountain the decrement of the height of the mercurial cylinder was not so considerable , but that i should perhaps have omitted the mention of this tryal , if it did not shew that our travailing baroscopes may be fit to be imployed about such experiments . and therefore , when i can recover some of my scatter'd papers , i shall by way of appendix subjoin to this some other observations , that i procur'd to be made by ingenious men , who had the opportunity of living near higher mountains . some further tryals i have recommended to be hereafter made by some other inquisitive persons ; and to make them the more instructive , i could wish that others would do what i should have done , if opportunity had befriended me . for i design'd to make the experiment at the bottom , the top , and the intermediate part of the hill , at three differing constitutions of air ; viz. when it should appear by a good ordinary baroscope , that the atmosphere was very heavy , when it should be found to be very light , and when it should have a moderate degree of gravity : and i hoped , that if sagacious experimenters should make these diversity'd observations on distant and unequal hils , good hints may result from the collations that may be made of the varying decrements of the mercurial cylinders height , according to the differing gravities of the atmosphere at several times , and the differing heights of the hils and stations where the observations should be made . i also indeavoured to get a baroscope carried down to the bottoms of deep mines ; partly , to try whether the atmospherical pillar being longer there then at the top , the mercury in the tube would not be impell'd up higher ; and partly , in order to other discoveries . but some impediments in the structure of those mines made it not very practicable to imploy barometers there ; which yet makes me not despair of success in some other mines , where the shafts or pits are sunck more perpendicularly . perhaps i told your lordship already by word of mouth , that i have been sollicitously endeavouring to get the torricellian experiment tried upon the pic of teneriff , but hitherto i have had no account of the success of my endeavours ; for which i am the more concern'd , because of the eminent ( if not matchless ) height of the mountain , of which you may receive some satisfaction , by what i am going to subjoin about it . an appendix about the height of mountains . forasmuch as on the one hand not onely kepler , but divers other modern writers of note , do endeavour to straiten the atmosphere , and make it lower by half than the least height to which , according to our estimation , it should reach ; and to countenance their opinion , will not allow the clouds to be often above a mile high , ( nor even the highest mountains to exceed two miles . ) and forasmuch as on the other side other learned men seem to make the clouds and the mountains of a stupendous height ; we , who take a middle way of estimating the height of the one and the other , hold it not unfit to subjoyn on this occasion some uncommon observations , in favour of our opinion , that we have obtain'd from inquisitive travellers . but first i will subjoyn a passage i have somewhere met with in ricciolus his almigestum novum , where he ( if i well remember ) relates , that the rector metensis ( as he calls him ) of the jesuites colledg affirm'd to him some years since , that he had measured the height of many clouds , without having found any of them higher than paces : which argues , that he met with some so high , though indeed the height of clouds must needs bevery various , according to the gravity or lightness , density or thinness , rest or agitation of the air , and the condition of the vapors & exhaltations they consist of . and if either that be true which we have formerly had occasion to mention concerning maignan's observation , or if it be true that sublunary comets ( for i speak not of celestial ones ) are generated of exhalations of the terrestrial globe , we may well conjecture that the atmosphere , ( especially if its height be not uniform , ) and even clouds ( especially those that have most fumes , and fewest vapors ) may reach much higher than cardan , kepler , and others have defin'd . but of the height of clouds ( which we have sometimes attempted to take geometrically ) we may have elsewhere occasion to speak again ; and therefore i shall now proceed to what i have to say concerning the height of mountains . which being an enquiry curious and difficult enough in it self , and of some importance in the disquisition about the height of the atmosphere , ( it being evident that that must reach at least as high as the tops of mountains , upon whose tops men can live ; ) i hope it will not be unacceptable to your lordship , if having a while since ( as i was intimating ) had the opportunity to discourse with some credible persons that have been upon the top of exceeding high mountains , particularly of the pic of tenariff , ( and especially with one gentleman , who was a few dayes before brought to satisfie the curiosity of our inquisitive and discerning monarch , by giving him an account of his journey , ) i acquaint you with those of the particulars , which i learn'd from thence , that are the most pertinent to our present purpose . first then whereas divers late mathematicians will not allow above two miles or half a german league ( and some of them not half so much ) to the height of the highest mountain ; the mountain we speak of , in the island of tenariff , one of the canaries or fortunate islands , so high , that , though perhaps i think those travellers i have taken notice of , speak with the most when they write , that the top of this mountain is to be seen at sea degrees off , i. e. at least threescore german leagues ; yet having ask'd the ingenious gentleman lately mentioned , mr. sydenham , from what distance the top of the sugar-loaf ( or highest part of the hill , so called from its figure ) could be seen at sea , according to the common opinion of seamen ? he answer'd , that that distance was wont to be reckon'd sea-leagues , of miles to a league : adding , that he himself had seen it about leagues off , and yet it appear'd exceeding high , and like a blewish pyramid , manifestly a great deal higher than the clouds . and what he related to me about the distance , was afterwards confirmed by the answers i receiv'd from observing men of differing nations , who had sail'd that way ; and particularly by a noble virtuoso , skill'd in the mathematicks , who was then admiral of a brave english fleet : and the above mentioned gentleman ( m r s. ) also told me , that sometimes men could from thence see the island of madera , though distant from it leagues ; and that the great canary , though leagues off , seem'd to be very near them that were on the top of the sugar-loaf , as if they might leap down upon it : thus far m r sydenham . by whose relation it appears , that this pic must be far higher than kepler and others allow mountains to be : for else it could not be seen at sea from so great a distance . and the learned ricciolus supposing it to be ( as some navigators report it to be ) discoverable at sea degrees off , calculates its height measur'd by a perpendicular line , and allowing too for refraction , to amount to ten miles , which altitude also the accurate snellius assigns it . but i fear this learned man may have been somewhat misinform'd by the navigators he relyes on , or else that the way of allowing for refractions is not yet reduc'd to a sufficient certainty . for i do not find by those who have purposely gone to the top of it , that the mountain is so high as his calculation makes it . and whereas the same eminent writer resolutely ponounces that the height of mount caucasus , deduction being made for refraction , is bolonian miles , ( which are considerably greater than the roman miles , ) i doubt that here likewise , though i question not his supputations if you grant him the grounds of them , he makes this mountain far higher than indeed it is . for the passage of aristotle , on which he founds his opinion , is obscure enough ; and aristotle , himself does sometimes take up reports upon hear-say , without over-strictly examining their truth or probability ; whereas all the navigators and travellers i have hitherto met with , ( and your lordship knows , that i have upon a publick account the opportunity of meeting often with such men , ) do almost unanimously agree , that the pic of teneriff is the highest mountain hitherto known in the world , and yet that is so far from being leagues high , ( as some eminent and even late writers would perswade us , ) that it is scarce a th part so high as ricciolus computes mount caucasus to be . for having ask'd m r sydenham , and others , what was the estimate made by the most knowing persons of the island of the height of the hill , he told me that his guides accounted it to be one and twenty mile high from the town called l'oretava , seated on the lower part of the hill ; from which . town to the sea there is miles of way alwayes descending . but in regard that the way , which amounted to miles in length , is , as other wayes whereby steep places are wont to be ascended , made to wind and turn for the conveniency of travellers ; i can scarce deduct less than thirds for the crookedness of the way : and accordingly having ask'd him , whether the perpendicular height of it had been accurately taken by any with mathematical instruments , he answered , that he could say nothing to that upon his own knowledg , but that a sea-man with great confidence affirmed himself to have accurately enough measur'd it by observations made in a ship , and to have found the perpendicular height of the hill to be about miles . which estimate agrees well enough with the calculations of ricciolus and snellius , if we lessen the distance from which the top of the hill is to be discovered , from german leagues of miles to a league , to the like number of common leagues at miles to a league . and because eminent writers have so confidently deliver'd prodigious things touching the height of this mountain , i will here , to confirm the estimate already made , adde these particulars , which i took from the gentleman 's own mouth , ( and which were afterwards confirm'd to me by another that went with him , and partly also by a d , who went up to the top at another time of the year , ) viz. that they begun their journey from l'oretava on the th of august , about of the clock at night , and travell'd till five in the afternoon on the munday following , resting two hours by the way , and travelling about miles of their way upon mules , which afterwards they were forc'd to leave , and betake themselves to their feet . resting upon munday till midnight , they resum'd their journeying , and travell'd till about nine the next morning , at which time they arriv'd at the top of the sugar-loaf , or highest pile of the mountain ; so that they travell'd in all but hours , in which , considering the steepness and ruggedness of the ways , and that they were forc't to goe above half way on foot , to which they were unaccustomed , t is likely enough that the length of the way did not much , if at all , exceed the computation of the guides . we have since endeavour'd , but without yet knowing what will be the succes , to have the height of this mountain carefully taken by skilful men . in the interim i shall not deny , but that if what aristotle and other authors report of mount caucasus be true , there may be far higher mountains than the pic of tenariff ; especially since there is one consideration , which perhaps you will not think despicable , that i find not taken notice of by those that have written of the height of mountains ; viz. that of two mountains that , measur'd by geometrical instruments , may appear to be of the same height , there may yet be a great inequality ; because the measurer measures onely from some plain piece of ground at the bottom of the hill to the top , whereas it may be , that the country , wherein one of those mountains stands , may be exceedingly much higher than that wherein the other is plac'd : which difference of heights in the several countreys , he that is to measure onely the height of one of the mountains , is not wont to take any notice of ; and consequently though in respect of the plains , adjacent to the feet of the mountains , their altitudes may be equal , yet in respect of the level or superficies of the terraqueous globe , consider'd as having no mountains at all but those two , the height of the one may far exceed that of the other ; and so the pic of tenariff being look'd upon from the level of the sea , may be much less high than some other hils , but may appear much higher than some other hils , which yet protuberating above the level part of some country which is it self generally exceeding high , may have its top more remote from the centre of the earth , than that of the pic , and would appear higher than it , if as well the one as the other were look'd upon from the same superficies of the sea. but to return to the height of the atmosphere ; in order to the making an estimate of what we have consider'd as to the height of mountains , i shall adde , that though by what has been already said touching the height of the pic , and other hills , it appears , that the atmosphere reaches far higher than many learned men would hitherto allow , yet we are not to think that the atmosphere may not reach almost incomparably higher than the tops of mountains . nor do i suffer my self to be concluded by what many comentators of aristotle and other writers are wont to teach touching the distinct narrow extent they allow to that sphere , within whose limits they would have the steams of the terrestrial globe to produce meteors . how far the height of mountains may make the air at the tops of them inconvenient for respiration , shall be ( god permitting ) consider'd , when i come to acquaint your lordship with my loose tryals about respiration . experiment xxiv . shewing that the pressure of the atmosphere may be exercis'd enough to keep up the mercury in the torricellian experiment , though the air press upon it at a very small orifice . by a very slight variation of the foregoing th experiment we may both confirm one of the most important and the least likely truths of the hydrostaticks , and remove an objection , which , for want of the knowledg of this truth , is wont to be urg'd against your hypothesis even by learned men . for divers of these , when they see the same phaenomena happen in the torricellian experiment , whether it be made in the open air , or in a chamber , are forward to object , that if it were , as we say t is , the weight of the air , incumbent on the stagnant mercury , which keeps that suspended in the tube from falling down , the mercury would not be sustain'd at any thing near the same height in the open air , where the pillar that is suppos'd to lean upon the stagnant mercury , may reach up to the top of the atmosphere , as in a close room , where they imagine that no more air can press upon it , than what reaches directly up to the roof or sealing . and when to this t is answer'd , that though if a room were indeed exactly clos'd , the sustentation of the mercury ought to be ascrib'd to some other cause than the weight of the imprison'd air , ( which other cause i have elsewhere shewn to be its spring ; ) yet in ordinary rooms there is still a communication between the internal and external air , either by the chimney , or , if the room have none , by some crevice in the window , or by some chink between the wall and the door , or at least by the key-hole . and when to this t is objected , that the orifice of the keyhole is much narrower than the superficies of the stagnant mercury , and consequently , though the atmosphere were not reduc'd to press obliquely on the mercury , yet , entring at so small an orifice , it could not press sufficiently upon it ; when , i say , in answer to this objection i have alleadg'd that hydrostatical theoreme , that the pressure , in such cases as ours , is to be estimated by the heights of the liquors and not the breadths , the assertion has been thought unlikely and precarious . to confirm therefore this hydrostatical truth , one may take the bended tube , mention'd in the th experiment ; and inclining it till the greatest part of the mercury pass from the shorter leg into the longer , the upper end of this shorter leg may by the flame of a lamp be drawn out so slender , that the orifice of it shall not be above an th or th part ( not to say a much lesse ) as big as 't was before . for this being done , and the tube erected again , if the tall cylinder of mercury be of the usual or former height , as we have found it , 't will appear congruous to our hypothesis , that the weight of the external air may exercise as much pression upon the stagnant mercury through a little hole , as when all the upper superficies of that mercury was directly expos'd to it . and if one have not the conveniency to draw out the shorter leg as is prescrib'd , one may nevertheless make the tryal , by carefully stopping up the orifice with a cork and cement , leaving onely ( or afterwards making ) a very small hole for the air to pass in and out . if i had not wanted a fit instrument , i would have tried to exemplifie the truth of what has been delivered , by adding to the glasses we imploy'd to make the v th . experiment , such a cover , as might be cemented on to the edge of the glass , having onely a very small hole in the midst , at which the atmosphere would be reduc'd to exercise its pressure ; and the like cover i would have made use of in the x th experiment , about the breaking of glass-plates in the unexhausted receiver , by the bare spring of the air. experiment xxv . shewing that an oblique pressure of the atmosphere may suffice to keep up the mercury at the wonted height in the torricellian experiment , and that the spring of a little included air may do the same . by adding a couple of little circumstances to the tryals lately propos'd , we may confirm two considerable articles of our hypothesis . for . if , in stead of drawing the shorter leg of our barometrical syphon ( if i may so call it ) directly upwards , or parallel to the longer leg as in the foregoing experiment , you make the slender part bend off so , as that , if it were continued , it would make a right angle with the longer leg of the syphon , or else an acute angle tending downwards ; this being done , i say , if when the tube is erected the mercury rest at its wonted station , 't will appear , that the pressure of the atmosphere may be exercis'd upon it as well obliquely , when the pipe that conveyes it is either horizontal , or opens downwards . and . if in stead of bending this slender pipe , one seal it up hermetically , the continuance of the mercurial cylinder at the same height will shew , that the spring of a very litle air , shut up with the presure of the atmosphere upon it , ( though no more than what the air here below is ordinarily expos'd to by the weight of the incumbent air , ) is able to support as tall a cylinder of mercury as the weight of the whole atmosphere , i. e. of as much of it , as can come to exercise its pressure against the mercury . nb. if when the shorter leg of the baroscope is seal'd up , you move the instrument up and down , the mercury will vibrate , by reason of the somewhat yielding spring of the imprisoned air ; but because of the resistance of the spring , the motion will be diversified after an odde and pretty manner : which may be easily perceiv'd by the impression it makes upon the hand , but not so easily describ'd . and because that , when the shorter leg is drawn out slender enough , after the instrument is furnish'd with quick-silver , t is easie to seal it up with the flame of a candle , without the help of any instrument at all , i shall here take notice to your lorship , ( which i could not reasonably do before , ) that it may on some occasions be convenient to seal up the barometer , before it be transported , and , in some cases , to incline the tube beforehand , till the quick-silver have quite fill'd the longer leg ; by this means the vibrations of the quick-silver will be less than otherwise they would be , and 't will be no trouble at all , when the instrument is brought to the design'd place , to break off the slender apex of the shorter leg , and so expose again the mercury to the pressure of the atmosphere . as about the former experiments , so about these two this advertisement may be given ; viz. that the same tryals , for the main , may be made without confining ones self to the propos'd wayes of making them . . for the first of these new tryals may be made by cementing very carefully on to the orifice of the shorter leg ( which need not be alter'd ) a short pipe of glass , whose upper end may be drawn out very slender , and bent either horizontally or downwards ; which is far easier to be done , than to draw out the shorter leg when the glass is furnish'd with mercury . . and as for the d tryal , that may be well enough made , by carefully stopping the unalter'd orifice of the shorter leg with a good cork , and our close cement , or with the later onely ; and when you would afterwards use this instrument as a baroscope , you need but heat a pin or slender wire red hot , and so burn a hole through the stoppel . and this expedient , which i could not conveniently advertise your lordship of sooner , may be of use when a travailing baroscope is to be often remov'd : because having once stopt the whole orifice well , t is far more easie to stop and open a pin-hole accurately , than to close and unstop the whole orifice of the tube . note , i endeavoured to confirm more than one of the foregoing particulars by this one experiment . having caus'd a portable barometer to be made with the shorter leg of a somewhat more than ordinary length , i afterwards caus'd the upper part of this leg to be drawn out very slender , ( as in this th experiment ; ) and lastly i caus'd the same shorter leg to be either about or somewhat above the middle bended downwards , so that the small orifice of the slender apex pointed towards the ground . this done , i was to have measur'd the height of the suspended mercury , but not having a fit ruler at hand , i then deferr'd , and afterwards forgot to do it ; but i remember , that neither i , nor some others vers'd in such experiments , to whom i shew'd it , took any notice that the mercury was less high than in ordinary barometers ; whence 't was concluded , that the atmosphere could exercise his pressure not onely at a very small orifice , ( which in our experiment did litle , if at all , exceed a pin-hole , ) but when the air must at this little orifice press upwards to be able to press upon the surface of the stagnant mercury : experiment xxvi . about the making of a baroscope ( but of litle practical use ) that serves but at certain times . to shew some ingenious men by a medium , that has not hitherto ( that i know of ) been made use of , that the not subsiding of quick-silver in an inverted tube , that is a little shorter than inches , or thereabouts , does not proceed from such a fuga vacui as the schools ascribe to nature , but from the gravity of the external air , i devised the following experiment . having made choice of a time , when it appear'd by a good baroscope , ( which i had frequently consulted for that purpose , ) that the atmosphere was considerably heavy , i caus'd galspipe , hermetically seal'd at one end , and in length about foot and a half , to be fill'd with quick-silver , save a very litle wherein some drops of water were put , that we might the better discern the bubbles , if any should be left after the inversion of the tube into an open glass with stagnant mercury in it . having by this means ( though not without difficulty ) freed the tube from bubbles , we so order'd the matter , that the quick-silver and the litle water that was about it , fill'd the tube exactly , without leaving any interval that we could discern at the top , and yet the mercurial cylinder was but very little higher than that of our baroscope was at that time . this done , the newly fill'd pipe was left erected in a quiet place , where the liquors retain'd their former height for divers dayes . but though an ordinary school-philosopher would confidently have attributed this sustation of so heavy a body to nature's fear of admitting a vacuum , yet it seems , that either she is not alwayes equally subject to that fear , or some other cause of the phaenomenon must be assign'd ; for when ( a pretty while after ) i had observ'd by the baroscope , that the atmosphere was grown much lighter than before , repairing to my short tube , i found that according to my expectation the quick-silver was not inconsiderably subsided , and had left a cavity at the top , which afterwards grew lesser , according as the atmosphere grew heavier . nb. . the tube imployed about this experiment , may be brought to the requisite shortness , either by wearing off a little of the glass at the orifice of it , or by increasing the height of the stagnant mercury , into which it hath been inverted . . when the quick silver in our short tube was much subsided , there appeared in the water that swam upon it a litle bubble , about the bigness of a small pins head , but , considering how careful we had been to free the tube from bubbles before we set it to rest , it may very well be , that this so small a bubble was not produc'd till after the subsiding of the quick-silver , whereupon the aerial particles in the water became less compress'd than before ; not to mention that the bubble ( such as it was ) appear'd very much greater than it would have done , if the pressure of the atmosphere had not been kept from it by the weight of the subjacent pillar of mercury . experiment xxvii . about the ascension of liquors in very slender pipes in an exhausted receiver . vvhat i related to your lordship in the th of the publish'd experiments , ( pag. . ) about the seemingly spontaneous ascension of water in slender pipes , has occasion'd the making of many tryals by the curious , whereby that experiment has been not a little diversify'd ; but because among those i have yet heard of none have been made in our engine , it may not be amiss to adde the following tryal , which may be of use in the examen of one or two of the chief conjectures that have hitherto been propos'd about the cause of that odde phaenomenon . we ting'd some spirit of wine with cocheneel , which being put into the receiver , and the air withdrawn , did exceedingly bubble for a pretty while . then little hollow pipes of differing sizes being put into it , the red liquor ascended higher in the slenderer than the others , but upon the withdrawing of the air there scarce appear'd any sensible difference in the heights of the liquor , nor yet upon the letting it in again . afterwards two such pipes of differing sizes , being fasten'd together ( at a distance ) with cement , were let down into the same spirit of wine when the receiver was well exhausted , notwithstanding which the liquor ascended in them , for ought we could plainly see , after the ordinary manner ; onely when the air was let in again , there seem'd to be some little ( and but very litle ) rising at least in one of the pipes . in this tryal this phaenomenon was noted : that though there appear'd no bubbles at all in the vessel'd spirit of wine , ( notwithstanding that we continued to pump , ) yet there did for a pretty while arise bubbles in that part of the liquor that was got into the slender pipes ; which i guess'd to proceed from the sustentation ( in part ) of the spirit of wine , made by the inside of the pipe whereto it adher'd . experiment xxviii . about the great and seemingly spontaneous ascension of water in a pipe fill'd with a compact body , whose particles are thought incapable of imbibing it . vpon occasion of the ( seemingly ) spontaneous ascension of water in slender pipes of glass , i consider'd that 't would be easie by another way to make it rise to a far greater height than hitherto had been done ; for since we had found by observation that , caeteris paribus , the slenderer the little pipes were that we imployed , the higher the liquor would rise in them ; and since the hydrostaticks had taught us , that often times even in very crooked pipes water would be made to ascend by the same wayes ( of raising it ) to the same perpendicular height ( or thereabouts ) as in straight ones ; i thought , that i might well substitute a powder , consisting of solid corpuscles heap'd upon one another , and included in a glass-cane in stead of the litle pipes i had hitherto used . for i consider'd the litle intervals , that would necessarily be left between these differingly shap'd and confusedly plac'd corpuscles , would allow passage to the water as did the cavities of the little pipes , and yet would in many places be straiter than the slenderest pipes i had us'd . and though beaten glass , or fine sand , &c. might have been imployed about this experiment , yet i judg'd it far more convenient to make use of some metalline calx , because the operation of the fire , making a more exquisite comminution of solid bodies than our pestles are wont to do , is fit to supply us with exceeding minute granes , that intercept proportionable cavities between them . upon this consideration therefore ( besides others to be hereafter hinted ) i took a strait pipe of glass , open at both ends , and of a moderate wideness , ( for it need not be very slender , ) and having tyed a linnen-rag to one end of it , that the water might have free passage in , and the powder not be able to fall out , we carefully and as exactly as we could , fill'd the cavity with minium , ( which is lead calcin'd , without addition , to redness ; ) and then having erected the tube , so that the bottom of it rested upon that of a somewhat shallow and open mouth'd glass , containing water enough to swim an inch or two above the bottom of the tube ; into whose cavity it did , as i expected , insinuate it self by degrees , as appear'd by a litle change of colour in that part of the minium which it reacht , till ( the open glass being from time to time supplied with fresh liquor ) it attain'd to the height of about inches . and then , our society expressing a curiosity to see it , and have it plac'd among better things , i was hinder'd from making any further observations with that particular glass . wherefore taking afterwards another tube , and some minimum carefully prepared , i prosecuted the experiment so as to make the water rise in the pipe about inches above the surface of the stagnant water ; and i guess'd it had risen higher , but , by reason that at the upper part of the minimum the difference of colour was so small , as not to be easily distinguishable with certainty , i forbore to allow a greater height to the ascension of the water : nor could i , where i then was , much promote the experiment , for want of such accommodations as i desir'd ; but about the experiment , as i try'd it , i shall take notice of the following particulars . i tryed some other powders besides red lead , ( as beaten glass , pieces of fine spunge , putty , &c. ) but did not find any of them do so well ; which success was yet perhaps but accidental , and therefore the tryal may be repeated , especially with putty , because that being a metalline calx as well as minium , consists of very small grains , and by reason of its great whiteness receives a greater change of colour by wetting than minium does ; in which , especially if it be very fine , the discoloration that water makes toward the upper part of the tube , is sometimes not so easie to be clearly discern'd . . i did indeed endeavour to remedy this inconvenience , by using , in stead of meer water , tincted liquors , as ink , tincture of safron , &c. but they seem'd not to rise near so high as water alone , as if the dissolv'd ingredients did by degrees choak the pores of the minium . . to have the grains of our powder more minute and the smaller intervals between them , i chose not onely to use the finest sort of minium i could procure , but also to sift it through a very fine searce , and to put it but by litle and litle into the tube , that by ramming it from time to time it might be made to lie the closer ; which expedients succeeded not ill . . it seem'd by a tryal or two ( for i am not sure the observation will alwayes hold , ) that if the tube were very slender , ( as about the bigness of a swans quill , ) the experiment succeeded not well . . it may be worth while to observe in what times the water ascends to such and such heights ; for at the beginning t will ascend much faster then afterwards , and sometimes t will continue rising or hours , and sometimes perhaps much longer . . one of the scopes i propos'd to my self in this experiment was to discover a mistake in the explication that some learned modern writers have given us of the cause of filtration ; for whereas they teach that the parts of filtre that touch the water , being swell'd by the ingress of it to their pores , are thereby made to lift up the water , till it touch the superiour parts of the filtre that are almost contiguous to them ; by which means these being also wetted , and swell'd , raise the water to the other neighbouring parts of the filtre , till it have reacht to the top of it , whence it s own gravity will make it descend . but in our case we have a filtre made of solid metalline corpuscles , where t will be very hard to shew that any such intumescence is produc'd , as the recited explication requires . . water ascends so few inches even in very slender pipes , as to seem much to favour their judgment , who dissallow the conjecture lately entertain'd by some ingenious men , ( particularly m r h. ) about the raising of the sap in trees after the like manner that water is raised in slender pipes ; but without fully delivering yet my thoughts of that speculation , i may take notice , that in the last tryal above recited , i made water to ascend near , if not above , foot ½ and if by so sleight an expedient , water may be made to rise as high as is necessary for the nutrition of some thousands of plants , ( for such a number there is , that exceed not foot / in height , ) one may without absurdity ask , why t is not possible that nature , or rather the most wise author of it , may have made such contrivances in plants , as to make liquors ascend in them to the tops of the tallest trees ; especially since , besides divers things that we may already suspect , ( as heat , and something equivalent to well plac'd valves , ) many others , that perhaps are not yet dreamt of , may probably concur to the effect . . as i formerly made , by bending the slender pipes we have been talking of , short syphons through which the water runs , without being at first assisted by suction , so i thought fit to try , whether i could not in larger pipes , by the help of minium , make much longer syphons . but though when the orifices were turn'd upwards , fine minium were ramm'd into both the legs , and the orifices were both of them clos'd , yet when they came to be again turn'd downwards , the weight of the minium would somewhere or other ( and for the most part at or near the flexure ) make some such chink or discontinuation , as to hinder the farther progress of the water . which impediment , though i judg'd it superable enough , ( especially by making at the flexure a little pipe or socket , by which both legs might be closely fill'd ) yet for want of accommodations and leisure it was left unsurmounted . upon which account also i did not satisfie my self about the success of some former tryals , as of the ascension of water into pieces of wood of differing sorts , the operation of the vicissitudes of the suns beams , and the absence of them upon liquors ascending in tubes fill'd with minium , &c. . whether the pressure of the outward air be the cause of the ascension of liquors in our tubes furnisht with minium , is a probleme , in order to whose solution i could acquaint your lordship with a contrivance , wherewith to make some tryals in our engine . but since it can scarce be well describ'd without many words , unless you express a particular curiosity to know it , i shall not trouble you with it : and the rather , because the best way i know of examining this difficulty belongs to the d part of this continuation , where mention is made of an attempt about it , which did not , i confess , displease me . experiment xxix . of the seemingly spontaneous ascension of salts along the sides of glasses , with a conjecture at the cause of it . to the same cause ( or the like ) with that of the ascension of water in slender pipes may be probably referr'd an odde phaenomenon , which though i remember not to have been mentioned by any chymical or other writer , i have not unfrequently observed as well by chance as in tryals purposely made to satisfie my self and others about the truth of it . the phaenomenon , in short , was this . that having in wide-mouth'd glasses ( which should not be very deep ) expos'd to the air a strong solution of common sea-salt or of vitriol , which reacht not by some inches to the top of the glass ; and having suffered much of the aqueous part to exhale away very slowly , the coagulated salt would at length appear to have lin'd the inside of the glass , and to have ascended much higher , not onely than the place where the surface of the remaining water then rested at , but than the place to which the liquor reacht when 't was first poured in . and if the experiment were continued long enough , i sometimes observed this ascension of the salt to amount to some inches , and that the salt did not onely line the inside of the glass , but , getting over the brim of it , cover'd the outside of it with a saline crust : which made them that saw how litle liquor remain'd in the glass , admire how it could possibly get thither . and though i have mentioned but the solution of vitriol and sea-salt , because they are much easier than others to be procur'd , and yet the experiment succeeds better in them than in some other far less parable salts ; yet they are not the onely ones by whose solutions the recited phaenomenon may be exhibited . as for the cause of this odd effect , though i shall not propose any thing about it with confidence , till i have further inquired into it , and especially till i have tryed whether the phaenomenon may be produced in an exhausted receiver ; yet , by what i have hitherto observed , i am inclin'd to conjecture , that it may be referr'd to such a cause as that of the ascension of liquors in pipes after some such manner as this . first , i observed , that in water and aqueous liquors , that part of the surface which is next the sides of the glass , is ( whatever the reason of it be ) sensibly more elevated than the rest of the superficies ; and if very litle clippings of straw or other such minute and light bodies , floating upon the water , chance to approach near enough to the sides of the glass , they will be apt ( which one would not expect ) to run up as t were this ascent of water , and rest against the sides of the glass . next we may take notice with the salt-boylers and chymists , that sea-salt is usually wont to coagulate at the top of the water in small and oblong corpuscles , so that as to these t is easie to conceive , to them that have considered the first observation , how numbers of them may fasten themselves round about to the inside of the glass . and besides sea-salt , i have found by tryal divers others , if their solutions be slowly enough evaporated , that will , whilst yet there remains a good proportion of liquor , afford saline concretions at the top of the water . and the fastning of saline particles to the sides of the glass may perhaps be promoted by the coldness that may be communicated to the corpuscles contiguous to the glass , by reason of the coldness which the glass may be suspected to have , upon the score of its density , in comparison of water . but to proceed : i consider , that by the evaporation of the aqueous parts of the solution , the surface of the remaining liquor must necessarily subside , and those saline particles , that were contiguous to the inside of the glass and the more elevated part of the water , having no longer enough of liquor to keep them dissolv'd , will be apt to remain sticking to the sides of the glass , and upon the least farther evaporation of the water will be a litle higher than the greater part of the superficies of that liquor ; by which means it will come to pass , that , by reason of the litle inequalities that will be on the internal surface of the adhering corpuscles of the salt , and perhaps also on the internal superficies of the glass , there will be intercepted between the salt and the glass litle cavities , into which the water contiguous to the bottom will ascend or be impell'd upon such an account as that , whereon t is rais'd in slender pipes . and when the liquor is thus got to the top of the salt , and comes to be exposed to the air , the saline part may , by the evaporation of the aqueous , be brought to coagulate there , and consequently to increase the height of the saline filme , ( if i may so call it ; ) which by the like means may be at length brought to reach to the very top of the glass , whence it may easily be brought over to the outside of the vessel , where the natural weight of the solution will facilitate its progress downwards ; and the skin of salt , together with the contiguous surface of the glass , may ( at length ) constitute a kind of syphon . to this explication it agrees well , that i have usually observed the saline filme hitherto mentioned to be with great ease separable from the glass in large fleaks ; which argues , that they did not stick close to one another except in some few places , but had a thin cavity intercepted between them , through which the water might ascend . nor is it repugnant to this explication , that in case the water ascended , it should , as it seems , dissolve the salt. for the liquor being already upon the point of concretion , is so glutted with salt , that it can dissolve no more . whence we may also render a reason , why , when the saline filme chances to reach to the outside of the glass , the liquor ( divers times ) does not run down to the bottom , but is coagulated by the way . and i have also had a suspicion , ( though i could not seasonably take notice of it before now , ) that when the concretion is once begun , the film may be raised and propagated , not onely by the motion of the liquor between the inside of it and the glass , but by the same liquor 's insinuating it self on the outside of the film into the small chinks and crevises , intercepted between the saline corpuscles , as ink ( especially if somewhat thin ) rises into the slit , and along the sides of the nib of a pen , though nothing but its very point be dipt in the surface of the liquor . and by this means the impregnated solution may as it were climb up to the top of the saline concretion , and by coagulating there adde to its height . some other circumstances i have noted of our phaenomenon , that agree with the propos'd explication , but perhaps it would not be worth while to spend more time about it . not to examine here whether what has been related , so as to make it probable that ascending water may carry up wherewithall to heighten and increase the pipes or vessels through which it rises , may contribute any thing more then was suggested in the former th experiment , towards the explication of the rising and diffusing of the sap in trees . experiment xxx . about an attempt to measure the gravity of cylinders of the atmosphere , so as that it may be exprest by known and common weights . vvhilst i was making the former experiments , 't was more than once my wish , that by knowing the just weight of a cylinder of quick-silver of a determinate diameter , and of or inches high , which is near the height that the air does usually counterballance , i might the better estimate the weight of a cylinder of the atmosphere of that diameter , and consequently make the better guesses how near the effects of the spring of the air ( as well as of its weight , ) produc'd by the help of our engine , approach'd to the utmost of what might have been expected , in case all the instruments imployed had been perfect , and all concurrent circumstances had been favourable : and upon this account i several times regretted my want of a long instrument of steel or hardned iron , wherewith i many years since made an observation , that was more carefully registred than preserved , of the weight of a mercurial cylinder of a determinate height as well as diameter ; which weight i did not think it so safe to determine by the help of glass-tubes , because t is very difficult to have them uniformly cylindrical , and to know that they are so , in regard that they are form'd but by blowing and drawing out , and , besides the inequality that may happen to the cavity upon other accounts , t is very difficult to make the sides of the glass equally thick , and to examine whether they be so or no. but at length lighting upon ( what i had too often wanted in the foregoing experiments ) a dexterous artificer , that chanced to come for a while to the place where i then was , i indeavour'd to repair my loss , as well as he could help me to do it , by causing him to turn very carefully a cylindrical piece of brass , of an inch in diameter , and inches in length , and open ( that it might be the better wrought ) at both ends , to one of which was exactly fitted a flat bottom of the same metal , fastned very close to it with little screws on the outside ; this being judg'd a better way , than if it had been turn'd all of a piece : this instrument being diligently counterpois'd in a trusty pair of scales , was carefully fill'd with mercury , which ( for greater caution ) we took out of a new parcel , that we had not yet imployed about other experiments , and finding it to weigh xvii ounces , one dram , gr : troy weight , ( or dr : gr : ) multiplying that by , there will come for the weight of a mercurial cylinder , of one inch in diameter , and inches in height , ( and so high i have divers times seen the mercury to be in a good barometer , ) about , l , ( i.e. l , ounces , and above three drams , troy-weight ; and almost , l . haberdupoise weight , ( i.e. l , ounces , and above drams , ) which is a greater weight than without such a tryal one would easily imagine that so short a cylinder of mercury , and much less that a cylinder of so light a body as air , being neither of them above an inch diameter , could amount to . note first , to examine at the same time the weight of the mercury , and its proportion to water , we did , before the mercury was pour'd into the brass-vessel , fill it with water , ( after which we wip'd it dry before the mercury was put into it ; ) and this liquor weighing drams , and gr : the proportion between the mercury and the water appeard to be that of / to : which though it seem somewhat of the least , yet your lordship may remember , that i formerly told you i had several times found the receiv'd proportion of to , between mercury and water , to be somewhat too great ; and besides that , in a vessel whose orifice was no lesse than an inch in diameter , t is exceeding difficult to be sure when t is precisely full either of water or mercury ; because the former has a superficies considerably concave , and the other one that is notably convex , and though we us'd some litle artifices ( which would be troublesome here to mention ) to estimate the proturberance of the one liquor , and the deficience of the other , as near the truth as could be , yet i am not sure but there may have been a few mercurial corpuscles more than there should have been , and that consequently some small abatement may have been made of the weight newly attributed to the whole mercurial cylinder of inches . . i had thoughts of making use of the barrel of a gun , of a convenient length , to find the weight of a mercurial cylinder of foot and / , but i preferr'd the instrument already made use of ( especially not being where i could have one bored after a peculiar way , ) not onely because i could not meet with one whose diameter was a just inch , and consequently as convenient for calculations , and because that the barrels of guns are often bor'd a litle tapering ; but because a skilful artificer confest to me , that they scarce ever bore such barrels , but with a foure-square bit , ( as they call it , ) which leaves the cavity too angular , or too imperfectly round ; whereas if an hexahedrical bit be imploy'd it will , as he affirm'd , make the cavity almost as cylindrical as can be reasonably desired . i say nothing here of making use for our purpose of a trunk , as they call a hollow cylinder of wood , because i elsewhere shew , that wood ( at least such as the trunks to shoot pellets with are wont to be made of ) is not of a texture close enough for such an use . . because in cylinders of mercury , inches is a height which the atmosphere is seldome heavy enough to be able to counterpoise , and because inches is somewhat nearer the middle between the greatest and the least heights , at which i have observed the mercury at differing times to stand in good barometers . your lordship may , if you please , abate a th part of the weight assign'd above to a mercurial cylinder of inches , ( though i take and ¼ , or thereabouts , to be somewhat a more usual height of the mercury , than precisely nine and twenty . ) . the weight of a mercurial cylinder in an aequilibrium with the atmosphere , and of one inch in diameter being thus setled , we may , by the help of the doctrine of proportions , and a few propositions , especially the th of the th book of euclides elements , easily enough calculate the weight of a cylinder of mercury of another diameter , and consequently the force of the pressure of an atmospherical pillar of the same diameter . for since according to the forenam'd th proposition of the th , cylinders of equal bases are to one another as their heights ; and since by the d proposition of the same . element , circles such as are the bases of cylinders ) are to one another , as the squares of their diameters ; and since lastly we suppose , that mercury being a homogeneous body , at least as to sense , the mercurial cylinders will have the same proportion to each other in weight that they have in bulk ; since , i say , these things are so , if , for instance , we desire to know what will be the weight of a cylinder of inches high , whose diameter is two inches , the rule will be this . as the square of the diameter of the standard cylinder , ( as i call that whose weight is already known ) is to the square of the diameter of the cylinder propos'd , so will the bulk of the former cylinder be to that of the later , and the weight of that to the weight of this . according to which rule , the square of inch ( which is the diameter of the standard cylinder ) being but , ( whereby your lordship may perceive how much the measure i pitcht on facilitates computations , ) and the square of ( which is the diameter of the propos'd cylinder ) being , the bulk or solid contents of this later cylinder , and consequently its weight , will be times as great as those of the standard cylinder ; and so , since the lesser has been already suppos'd to weigh , l haberdupoise , the mercurial cylinder of two inches in diameter , will weigh , l of the same weight . experiment xxxi . about the attractive virtue of the loadstone in an exhausted receiver . some learned modern philosophers , that have attempted to explicate the cause and manner of magnetical attraction or coition , give such an account of it , as supposes , that the air between the two magnetical bodies , being driven away by their effluviums from between them , presses them on the parts opposite to those where the contact is to be made ; and upon some such score ( for i must not now stay to deliver their theories circumstantially ) the air is suppos'd to contribute very much to the attraction and sustentation of the iron by the loadstone : wherefore partly to examine this opinion , and partly for some other purposes ( not necessary now to be mentioned ) we thought fit to make the following exptriment . we took a small but vigorous loadstone , cap'd and fitted with a loose plate of steel , so shap'd , that when it was sustained by the loadstone , we could hang at a litle crook , that came out of the midst of it , and pointed downwards , a scale , wherein to put what weights we should think fit . into this scale we put sometimes more and sometimes less weight , and then by shaking of the loadstone as much as we guess'd it would be shaken by the motion of the engine , we found the greatest weight , that we presum'd it would be able to support , in spite of the agitation 't would be exposed to , which prov'd to be , besides the iron-plate and the scale , vi ounces troy weight , to which if we added half an ounce more , the whole weight appear'd too easie to be shaken off . this done , we hung the loadstone , with all the weight it sustain'd , at a button of glass , which we had procur'd to be fastned on to the top of the inside of a receiver , when 't was first blown , and though in about exuctions we usually emptied such receivers as as much as was requisite for most experiments ; yet this time , to exhaust it the more accurately , we continued pumping till we had exceeded twice that number of exuctions , at the end of which time shaking the engine somewhat rudely , without thereby shaking off the weight that hung at the loastone , the iron seem'd to be very near as firmly sustain'd by it as before the air began to be pump'd out . i said very near , rather than altogether , because that the withdrawing of the air , though it be not suppos'd to weaken at all the power of the loadstone precisely considered , yet it must lessen its power to sustain the steel , because this in so thin a medium must weigh heavier , than in the air , by the weight of as much air , as is equal in bulk to the appended body . some other magnetical tryals ( and also some electrical ones ) i remember i attempted to make by the help of our engine , but not having the notes i took of them now at hand , i shall suspend the mentioning them , till i can give your lordship a more punctual account of them . experiment xxxii . shewing , that when the pressure of the external air is taken off , t is very easie to draw up the sucker of a syringe , though the hole , at which the air or water should succeed , be stopp'd . having taken notice , that some learned opposers of the modern doctrine about the weight of the atmosphere think themselves more than ordinarily befriended by the difficulty we find in drawing up the embolus or sucker of a syringe , when the hole , at which the air or water should succeed , is stopt , and by the violence , with which , as soon as t is let go , tis , as they imagine , drawn back . and supposing the reason of this confidence of theirs to be , that men have not yet been able in these phaenomena ( as in some others ) to prove the interest of the atmosphere's gravity by direct or confessedly analogous experiments ; i presum'd it will not be unwelcome to your lordship , if i here fortifie the speculations that have been or may be propos'd to explicate these things according to the hypothesis of the weight of the air , by what we tried to that purpose , among others , when we were making use of a syringe in our engine . the i. tryal . we took a syringe of brass , ( that metal being closer and stronger then pewter , of which such instruments are usually made , ) being in length ( in the barrel ) about inches , and in diameter about inch ⅜ and having , by putting a thin bladder about the sucker , and by pouring a litle oyl into the cavity of the cylinder ( or barrel , ) brought the instrument to be stanch enough , and yet the sucker to move to and fro without much difficulty , we thrust this to the bottom ( or basis ) of the barrel to exclude the air , and having unscrew'd and laid aside the slender pipe of the syringe ( which in this and some other tryals was like to prove not onely needless , but inconvenient ) we carefully stopt the orifice , to which the pipe in these instruments is wont to be screw'd , and then drawing up the sucker we let it go , to judg by the violence , with which it would be driven back again , whether the syringe were light enough for our purpose , and finding it to be so , we fastned to the barrel a ponderous piece of iron to keep it down , and then fastning to the handle of the rammer ( or axle-tree of the sucker ) one end of a string , whose other end was tied to the often mentioned turning-key : we convey'd this syringe , and the weight belonging unto it , into a receiver ; and having pump'd out the air , we then began to turn the key , thereby to shorten the string that tied the handle of the syringe to it ; and , as we foretold , that the pressure of the air , lately included in the receiver , being withdrawn , we should no more find the wonted resistance in drawing up the sucker from the bottom of the cylinder , so we found upon tryal that we could very easily pull it up without finding any sensible resistance . however having thought fit to repeat the experiment , ( which we did with the like success , ) lest it might might be objected , that this want of resistance might proceed , as partly from our imploying the turning-key to raise the sucker , so principally from some unperceived leak , at which the air may be suppos'd to have got into the cavity of the cylinder ; i thought fit not onely to examine by tryal , after the receiver was remov'd from off the pump , whether the syringe were not stanch , ( upon which i found that i could not , without some straining , draw up the sucker even a litle way , and that it would be violently beaten back again , ) but also in one of these experiments to make this variation ; that when , the receiver being exhausted , we had drawn up the sucker almost to the top of the barrel by such a string as was purposely chosen somewhat weak , we kept the parts of the syring in that posture , till we had open'd a passage to the outward air , upon whose ingress the sucker was ( as we intended it should be ) so forceably deprest , that it broke the string by which it was tied to the turning-key , and was violently driven back to the lower part of the barrel , & that notwithstanding these two disadvantageous circumstances ; one , that the string was not so weak , but that one , whom i imploy'd to try it before it was fastned to the syringe , made it sustain a lump of iron that weighed between four and five pound ; and the other , that yet this string was broken long before all the air , that flowed in to fill the receiver , had got in : so that the pressure of all the admitted air would doubtless have broken a much stronger string , if we had imploy'd such a one to resist the depression of the sucker , which will yet be more evident by a phaenomenon of our syringe , that i shall presently have occasion to relate . the ii. tryal . containing a variation of the foregoing . we took the syringe imploy'd in the foregoing experiments , and having found by tryal that it was , though not perfectly , tite , ( nor altogether so much so as before , ) yet enough so for our present purpose , ( since , when the orifice of the vent in the basis was stopt , if the sucker were more forceably drawn up a litle way , and then let go , it would hastily return , or rather violently be impell'd back towards the bottom of the barrel , ) we made it serve us as well as we could for the following experiment . of this syringe we did very carefully with a cork and our cement close the vent ; and then having tied to the barrel of the syring a weight that hapned to be at hand , ( and to amount to pound , and as many ounces , ) we suspended the rammer of the syringe by a string in a large receiver ; and then causing the pump to be applied , we made or exuctions of the air , without any appearance of change in the syringe : but because i had judg'd the above mentioned weight sufficient , and suppos'd that the little air still remaining in the receiver , had yet too strong a pressure to be surmounted by it , i caus'd the pumping to be continued , and within or three exuctions more i perceiv'd the cylinder to begin to be drawn down ( though but very slowly ) by the weight hanging at it , ( assisted by its own gravity : ) and likewise tried ( after having purposely stopt a while the working of the pump ) that just upon a fresh suck the descent would be manifestly accelerated . and when we had suffer'd the barrel and weight to slide down as far as we thought fit , we let in the external air , which ( as was to be expected ) rais'd them both again much faster than they had subsided . nb. there would not have needed any thing near so great a weight to depress the barrel of the syringe , but that it is difficult in such an instrument to make the sucker fill it accurately enough , without making it somewhat uneasie to be mov'd to and fro : upon which account t was necessary that a weight should be added , not onely to surmount the pressure of the air remaining in the receiver , ( which was not , nor needed to be diligently exhausted in this experiment , ) but to overcome that resistance , which we just now noted the inequalities of the inside of the cylinder and those of the sucker to give to the motion of the one in or over the other . and yet for all this t is not easie , though it be not impossible , to make one of these syringes very tight , especially when the nose is well stopt , and the sucker drawn up ; there being often some litle air that strains in between the sucker and the barrel , and some that will be harbour'd between the sucker ( though thrust home ) and the bottom of the barrel , besides what may lurk between the same sucker and the cork that stops the orifice of the vent . nor were we confident , that our syringe did not at length let some aerial particles insinuate themselves into the cavity , which the depression of the barrel had made betwixt the bases of that barrel and the sucker : and in such cases we ought not to wonder , if upon the return of the air the barrel and weight be not impell'd up all together to the same height they rested at , when they were first suspended in the receiver . . it agreed very well with our doctrine , that as the cylinder and weight began not to fall , till a great quantity of air had been pump'd out of the receiver , so they did not begin to move upwards presently upon the freedom that was allow'd the air to return into the receiver . for till it had continued a pretty while flowing in , there was not enough of it entred to restore by its pressure the cylinder and the annexed weight to their former situation . . what has been deliver'd about our experiment may be confirm'd by this variation which we made of it : that having substituted a far heavier weight instead of that lately mention'd , the depression of the barrel of the syringe succeeded or times one after another much sooner than formerly , viz. about the sixth , or at most , the seaventh exuction . experiment xxxiii . about the opening of a syringe , whose pipe was stopt in the exhausted receiver , and by the help of it making the pressure of the air lift up a considerable weight . though the trial i am about to relate , had not all the success i desir'd , yet perhaps it will not be impertinent to make mention of it , because there is not any sort of experiments , that is wont so much to perswade the generality of spectators , of the great force of the pressure of the air , as those , wherein they plainly see heavy and solid bodies made to ascend , ( upon the operation of the air on them , ) without seeing any other thing lift them up . we took the often mention'd syringe , and having clos'd up the hole at the bottom with good cement , we ty'd to the barrel a hollow piece of iron , that serv'd us for a scale , into which we put divers weights one after another , trying from time to time whether , when the sucker was forceably drawn up , and held steddily in its highest station , the weight tyed to the barrel ( which was held down , whilst the sucker was drawn up , and afterwards let go ) would be considerably rais'd . and when we perceiv'd , that the addition of half a pound , or a pound more , would make the weight too great to be so rais'd , we forbore to put in that increase of weight ; and having tied the handle of the rammer to the turning-key , we convey'd the syringe together with its clog into a receiver , out of which a convenient quantity of air being pump'd , we were thereby enabled easily to draw up the sucker without the cylinder ; after which having let in the air , the by-standers concluded , that the weight was rais'd a litle , which yet i would not have allow'd , if we had not been able , by inclining the engine and the receiver , to make the syringe and weight a litle to swing . but to make the effect more evident , i caus'd a two pound weight to be taken out , and then the receiver being somewhat exhausted , and the air readmitted , the clog , when all the air was come in , was swiftly raised , and as it were snatch'd up from the midle to the upper part of the suspended rammer . it is no easie matter to measure , with any certainty and exactness by a syringe , the weight of an atmospherical pillar equal to it in diameter , especially if there be any imperfection in the syringe , either because the sucker does not go close enough , in which case it can scarce be stanch , or because by its pressure against the inside of the barrel ( which often happens if it be too close ) it hinders the sucker and barrel from sliding without resistance by one another , and consequently there is an undue resistance made to the endeavour of the atmosphere , to raise the barrel and weight . and therefore , though our syringe being , upon the account of some ill accident , less in order than it was in some of the foregoing experiments , i must not conclude that a cylinder of the atmosphere of the same wideness with it , is equipollent to no greater a weight , than that which was taken up in our trial , yet we may safely conclude that so slender a pillar of the atmosphere is able to raise by a syringe at least such a weight , as in our experiment it actually lifted up , which amounted to about sixteen pound ( haberdupoise weight , ) for it exceeded fifteen pound and three quarters , besides the weight of the syringes barrel it self . experiment xxxiv . shewing , that the cause of the ascension of liquors in syringes is to be deriv'd from the pressure of the air. i shall not here trouble your lordship with what i have elsewhere propos'd about the explicating of suction : but as by the lately recited experiments ( i mean the , , and ) it has appear'd , that t is to the pressure of the external air that we should ascribe the difficulty of drawing up the sucker of a syring , when the pipe ( or the vent ) is stopt ; so i shall now endeavour to shew , that the ascension of liquors , which follow the sucker when t is drawn up , the pipe being open , depends also upon the pressure of the air , ( incumbent on that liquor . ) if i had been furnish'd with very tall receivers , and such other glasses as i could have wish'd , i had tried the following experiments with water , as well as quick-silver , but for want of those accommodations i was reduc'd to make my experiment with the later onely of those liquors , which yet will i hope sufficiently make out what was intended . the i. tryal . we took a small receiver , shap'd almost like a pear , cut off horizontally at both ends , ( being the same cap'd glass that is elsewhere mentioned in the accounts of other experiments : ) we also took the syringe formerly describ'd , and having fastned on to it with good cement , in stead of its own brass-pipe , a small glass pipe of about half a foot in length , we put this syringe in at the narrow end of the receiver ; to whose orifice was ( afterwards ) carefully cemented on the brass-cap with the turning-key , whereto was tied by a string the handle of the rammer . then having conveniently plac'd upon the engine a very short thick glass shap'd like a sugar-loaf , ( which was made use of for want of a better , ) with a sufficient quantity of quick-silver in it ; we so placed the receiver over it , that the lower end of the pipe of the syringe reacht almost to the bottom of this glass , and consequently was immerst a pretty way beneath the surface of the quick silver . we had also poured a little water in the upper part of the syringe , that no air might get in between the sucker and the cylinder , notwithstanding that by some accident or other the syringe was become somewhat less tite than before . and last of all we cemented the receiver to the engine after the usual manner . that which now remained , being to try the experiment it self , in order to which all this had been done , the air was pump'd out of the receiver , ( and consequently out of the little glass that held the mercury , ) and then the sucker being warily drawn up , we could not see the quick-silver ascend to follow it , though a litle water , which it seems the outward air had thrust in between the sucker and the cylinder , was either rais'd or stopt in the glass-pipe of the syringe , ( whereof yet much the greatest part remain'd unfill'd ; ) of which the reason according to our hypothesis was manifest , namely , that the air being pump'd out of the receiver , the litle that remain'd had not strength enough to press up so ponderous a liquor as the quick-silver into the pipe , ( though even that litle unexhausted air might have spring enough left to raise a litle water . ) and since it appear'd by this , that without the pressure of the air the quick-silver would not be elevated , we thought it seasonable to shew , that by the pressure of the air it would . whereupon the air being let slowly into the receiver , the mercury was quickly impell'd up at least to the top of the glass-pipe , ( though by reason of some unperceiv'd leak it was not long sustain'd there . ) and for further satisfaction , when the experiment was to be tried over again , we order'd it to be so made , that it might plainly be observed , that though when , the receiver not being yet exhausted , the sucker was drawn up but one inch , the mercury would be rais'd to the upper part of the glass-pipe of the syringe , yet after the exhausting of the receiver , though the sucker was drawn up twice as high , there appear'd no ascension of the mercury in the pipe , ( whose lower part onely was darkned by the litle glass which contain'd that fluid metal . ) before i dismiss this experiment , i must , to make good a promise i made your lordship , acquaint you with a phaenomenon , which does not a litle confirm our doctrine , according to which it was easie both to foresee and to explain it : the phaenomenon was , that if when the air was diligently pump'd out of the receiver , the sucker were endeavour'd to be pull'd up , it could not be so , without much difficulty and resistance , such as was formerly found when the vent of the syringe was stopt , of which in our hypothesis the reason may be clearly this ; that there being no common air in the receiver to assist by its pressure ( whether immediate or mediate ) the raising of the sucker , this could not be raised but by a force great enough to surmount the weight of the external air or atmospherical pillar that lean'd upon it . so that as the other phaenomena of our experiments manifest , that the raising of liquors by a syringe , which is commonly ascrib'd to attraction , depends upon the pressure of the air ; so by this phaenomenon it appears , that the difficulty of opening a syringe , whose pipe is stopt , need not be attributed to such a fuga vacui as vulgar philosophers refer it to ; since in our case the same difficulty was found , though the pipe were open , and the liquor 't was immerst in , might have had free access to the place deserted by the sucker . the ii. tryal being a prosecution of the former attempt . to vary as well as confirm the foregoing experiment , we caus'd the syringe to be tied fast to a competently ponderous body that might keep the cylinder unmov'd , when the sucker should be drawn up . we also cemented on to the vent or screw at the bottom of the syringe a pipe of glass of about two inches in length , ( which should have been longer , but that then there would not have been room in the receiver for the pulling up of the sucker , ) and having plac'd the heavy body whereto the syringe was tied upon a pedestal of a convenient height , that the glass-pipe might be all seen beneath it , and a very low viol almost fill'd with quick-silver might be so plac'd underneath the pipe , that the stagnant mercury reach'd a good way above the immerst orifice of the said pipe. these things being thus provided , and the handle of the syringes rammer being tied with a string to the turning-key that belong'd to the brass-cover of the receiver , this vessel was cemented on to the engine , and by it exhausted after the usual manner . when this was done , we look'd upon the syringes glass-pipe above mentioned , and being able to see through it , ( whereby we were certain that it was not yet full of quick-silver ) we did by the string draw up the sucker to a good height , but could not perceive the pipe to be fill'd with any succeeding mercury . wherefore warily letting in some air , we quickly saw the mercury impell'd to the very top of the pipe ; and we concluded from the quantity of quick-silver that was rais'd , that a pretty deal was also driven into the cavity of the cylinder . nb. i had once before seen the mercury ascend into the pipe upon the letting in of the air into the emptied receiver , but it seeming somewhat difficult to me to determine whether the sucker had been raised , because there was no mark to guide my aestimate by , i thought it might be suspected , that in case the sucker had not been rais'd , the ascension of the quick-silver might have proceeded from hence , that the air contain'd in the glass-pipe , breaking out through the stagnant mercury upon the exhausting of the receiver , the quick-silver might upon the return of the air into the receiver be prest up into the place deserted by the air , that broke out of the pipe. wherefore we caus'd a string to be tied about the rammer , as near as we could to the top of the cylinder , by which means , when the receiver was the next time exhausted , we perceiv'd , that by drawing up the sucker vve had rais'd it about two inches , if not more , and yet vve could not discern any mercury to follow it , ( the glass-pipe still continuing transparent , ) till we had let some air return into the receiver . this experiment joyn'd with those we have formerly related to have been tried with our syringe , may teach us , that if a syringe were made use of above the atmosphere , neither the stopping of the pipe vvould hinder the easy drawing up of the sucker , nor the drawing up of the sucker , though the pipe vvere not stopt , vvould raise by suction the liquor vvhich the pipe was immerst in . postscript . since the last recited experiment was made , and written , finding some of our instruments to be in better order than they were when that tryal was made , vve thought fit to endeavour by that which follows , to repair an omission or two , that formerly we could not well avoid . having then caus'd such a glass-pipe , as has been lately mentioned , to be vvell cemented on to the syringe , ( vvhose sucker did now move more easily , and yet fill the barrel more exactly , than before , ) i order'd ( being to be absent for a while my self ) that the pipe should be fill'd with spirit of wine tincted with cocheneel , that the liquor and its motions might be the better discern'd , and that the pipe being fill'd , that air might be excluded , which vvould else be harboured in the pipe , ( which caution was omitted in the foregoing experiment . ) and this the person , to whom i committed it , affirm'd to have been carefully done , though when he inverted the pipe thus fill'd into the rest of the red liquor , that was put into a viol , he could not possibly do it so well , but that a bubble of air got into the pipe , and took up some ( though but a litle ) room there . by that time , i was call'd upon , to see the event of the tryal , and could come to look upon it , the receiver was almost quite exhausted ; vvherefore after i had made the pumping be continued a litle longer , and perceived that the tincted spirit was fallen down out of the pipe , and that which lay in the viol seem'd almost to boyl at the top , by reason of the emersion of numerous bubbles , i caus'd the sucker to be , by the help of the turning-key , drawn up ( by our aestimate ) about two inches and a half , notwithstanding which vve could not perceive the spirit of wine to rise in the pipe , ( though the pumping were before left off . ) for vvhich reason i order'd the air to be let in very leisurely , upon which vve could plainly see that the red spirit was quickly driven up to the top of the pipe , and that it was so likewise into the cavity of the barrel , appeared , when the receiver was removed , by the small quantity of liquor that remained in the viol , and the plenty of it which came out of the syringe . nb. that if i had not vvanted dexterous artificers , to work according to a contrivance i had design'd , i had attempted to imitate , by the help of the bare spring of the air , such experiments , as in the lately recited tryals vvere made to succeed , by the help of the pressure exercis'd by the air upon the account of its weight . experiment xxxv . shewing , that upon the pressure of the air depends the sticking of cupping glasses to the fleshy parts they are apply'd to . t is sufficiently known , that if the air within a cupping glass be rarified by the flame of tow , flax , or the like , ( burn'd for a litle while in it , ) and the glass be presently clapt upon some fleshy part of a mans body , there will quickly ensue a painful and visible swelling of the part cover'd by the cupping glass . t is also known , that this experiment is wont to be urg'd by the schools as a clear proof of that abhorrence of a vacuum they ascribe to nature ; for , say they , the reason of this phaenomenon is plainly , that the internal air of the cupping glass , praeternaturally rarified by heat when the instrument is applied , that heat after a while ceasing , the succeeding cold must again necessarily condense the air ; and so this contracted air being no longer able to fill the whole space it replenished before , there would ensue a vacuum , if the flesh covered by the cupping glass , or adjoyning to it , did not swell into the cavity of it , to fill the place deserted by the air. those moderns that assert the weight of the atmosphere , do thence ingeniously endeavour to deduce the phaenomenon . and indeed if to their hypothesis about the airs weight , the consideration of its spring be added , 't will be easie enough to explicate the phaenomenon , by saying , that when the cupping glass is first set on , though much of the air it formerly contain'd were a litle before expell'd by the heat , yet the same heat , increasing the pressure of the remaining air , is the cause that the absence of the air driven out of the glass , does not immediately occasion so sensible a pain : but , when that adventitious agitation of the included air ceases , that air having now , because of the paucity of its corpuscles , but a weak spring , can no longer press upon the part covered by the cupping glass neer so strongly , as the outward air does by its weight press upon all the neighbouring parts of the flesh : by which means ( according to what we have more than once explicated already ) some of the yielding flesh ( or other body covered by the skin ) must be forceably thrust into the cavity of the cupping glass , where there is less pressure , then at the outside of it . and the fibres and membranous parts being thus violently stretcht , there must needs follow a sensible pain as well as tumour . which tumour yet does not fill up the cupping glass , not onely because of the resistance of the skin to be so far distended , but also , if the included air have not been much rarified because of the spring of the imprisoned air , ( which grows so much the stronger , by how much the swelling flesh reduces the air into less room , ) as i have sometimes tried , by applying a cupping glass to quick-silver , or even to water , which will rise in it but to a certain height . but though by this , or some such explication , the argument urged by the schools in favour of the fuga vacui may be sufficiently enervated ; yet it suited better with the design of this treatise to propose some new experiment , to illustrate our hypothesis ; and though it seem'd to be far more difficult to do it in reference to cupping glasses , than to other subjects , yet i pitcht upon two different wayes of experimenting ; whose success not disappointing me , i shall now give your lordship an account of them , we took a glass of about one inch and a half in diameter , but a good deal longer , than an ordinarily shap'd cupping glass of that breadth would have been , that there might be the more room for the flame to burn in it , and rarifie the air. we also provided a receiver shap'd almost like a pear , this receiver was open at both ends ; at the sharper whereof there was but a small orifice , but at the obtuse end there rose up a short neck , whose orifice was wide enough to admit with ease the newly mentioned cupping glass without touching the sides of it , and we were not willing it should be much larger , lest it should not be so exactly cover'd by the palm of the hand that should be laid upon it , and lest also the hand should be broken or hurt by the too great weight of the atmosphere , when the included air should be withdrawn from under it . these things being thus prepared , and the smaller orifice of the receiver being fastned with cement to the engine , i caused the cupping glass to be fastned , with the mouth upwards , to the palm of the hand of a youth , ( whom your lordship may remember to have seen with me , ) whose hand seem'd fram'd by nature for this experiment , being broad , strong , and very plump . and having pull'd the glass , to try whether it stuck well on , i caus'd him to put it into the receiver , and lay his hand so upon the orifice lately mentioned , that it might serve for a cover to it , and hinder any air from getting in between them . that which we pretended was , that the receiver being but small , ( that it might be quickly exhausted , and so not put the youth to a long pain , ) upon an exuction or two made with the pump , of the air about the cupping glass , the remaining air should have its pressure so far weakned , as not to be able to support the cupping glass ; especially since if the air without the cupping glass ( but yet in the receiver ) should be more rarified by the removal of that which had been pump'd out , than the air included in the cupping glass was by the precedent heat ; this last mentioned air having a stronger spring ( or tendency to expand it self ) than the external air of the receiver , the glass must needs fall down , or rather be thrust off , though , in case there had been no air at all left in the cavity of the cupping glass , the air in the receiver would by its pressure sustain a far greater weight . the event of our trial agreed very well with our conjecture . for upon the first suck the cupping glass fell off , the weight of the atmosphere pressing so hard upon the young mans hand , that , though he be more than ordinary strong , he complain'd he could very hardly take it off the glass it was almost thrust into , and , a while after , that his hand was very sore . but this last inconvenience became not so quickly very sensible , but that we had time to repeat our experiment , by fastning the cupping glass more strongly than before ; so that he complain'd that it drew in his hand very forceably , and though that part be not wont to be fleshy , yet the tumour occasioned by the cupping glass was manifest enough to the eye : but as before , so now , at the very first turning of the stop-cock , ( to let out the air of the receiver , ) the cupping glass fell off . experiment xxxvi . about the making , without heat , a cupping glass to lift up a great weight . the other experiment i lately told your lordship we had made , to illustrate our doctrine about the cause of the sticking of applied cupping glasses , was tried after the following manner . we took the brass-hoop or ring , mentioned in the th and th experiments , and cover'd it with a bladder , ( which was wetted to make it the more limber , ) and was so tied on to it , ( which was easie to do , ) that the bottom of the bladder covered the upper orifice of the hoop , and was stretcht ( though not strongly ) upon it , almost like the membrane that makes the head of a drumm ; and the neck of the bladder was tied with a string near the middle of the lower orifice of the hoop , and in this lower part of the bladder we made two or three small holes for the air to pass in and out at . then having plac'd at the bottom of the often mentioned capp'd receiver a thick piece of wood , that had a hole in it , to receive the neck of the bladder , we so plac'd the cover'd hoop upon this piece of wood , that the upper part of the bladder lay parallel to the horizon . this done , we suspended , at the turning-key belonging to the cap of our receiver , a blind head ( as chymists call it ) of glass , which for want of a true cupping glass we were fain to substitute , and which indeed was not very unlike one either for shape or size ; and to the upper part of this glass we fastned a large ring of metal , the better to depress it , and make it lean strongly on the bladder . these things being thus made ready , and the receiver cemented on to the engine , we did by help of the turning-key let down the cupping glass , ( for so we shall hereafter call it , ) till it came almost to touch the level superficies of the bladder ; and when the receiver was as far exhausted as we thought fit , ( but not near as far as it might have been , ) we let down the cupping glass a litle lower , so that it lean'd upon the bladder , and touch'd it with all the parts of its orifice : so that the cupping glass with the subjacent bladder was become an internal receiver ( if i may so call it , ) whose air was considerably expanded , and consequently weakned as to its spring . all this being done , we warily let the air into the receiver , and thereby the air , that did surround the cupping glass , ( which we just now called the internal receiver , ) having now a stronger pressure than the air in the cupping glass could resist ; the bladder , on which the cupping glass rested , was as we look'd for , thrust up a pretty way into the cavity of the glass , in which it made a conspicuous tumor ; and was made to stick so close to the orifice of it , that one would have thought that the bladder had been violently drawn in , as the skin is wont to be in the ordinary applications of cupping glasses . and because we took notice , that though this glass were not capacious , ( for it scarce held a pint of water , ) yet the orifice of it was not very narrow , ( being in diameter an inch and ⅘ , ) we thought fit in repeating the experiment to adde something that seem'd odd enough , and was fit to manifest that cupping glasses may , without heat , by the bare pressure of the external air , be more strongly fastned , than for ought we know they are by the help of flame . having then reiterated the former experiment with this onely variation , that we exhausted the receiver further than before , we took out the cupping glass and the bladder , which together with the included brass-hoop was hanging at it ; and then having tied the glass to the hook of a good statera , and tied a large scale to the neck of the bladder , we put in by degrees weights into the scale , till we had loaded it enough to force off the bladder from the glass ; which hapned not till the whole weight , that tended to draw down the bladder , amounted to pound ( if not better , ) of sixteen ounces in the pound . nor did we doubt , but that the pressure of the atmosphere would in our experiment have kept up a much greater weight , if we had , before we let in the outward air , diligently exhausted the receiver ; which we had purposely forborn to do , for fear the too disproportionate pressure of the external air should break the bladder : which puts me in mind of adding , upon the by , that as more weight was put into the scale , the bladder ( stretcht more and more by the weight on one side , and the air on the other , ) appear'd to swell higher in the cavity of the glass . experiment xxxvii . shewing , that bellows , whose nose is very well stopt , will open of themselves , when the pressure of the external air is taken off . it is wont by the peripateticks and others to be made a great argument for the fuga vacui which they attribute to nature , that if the nose of a pair of bellows be well stopt , one cannot open them by raising the upper board from the lower . but of this another reason may be easily assigned , without determining whether there be a vacuum or no , namely the weight and pressure of the air : for when the nose of a pair of bellows , that are tite enough , is well stopt , no air being able to insinuate it self upon the disjoining of the boards into the cavity made by that disjunction , this cannot be effected , but by such a force as is almost able ( i say almost , because ordinary bellows cannot be so well shut , but that there will remain some air in them , whose spring will facilitate the opening of them ) to raise an atmosphere pillar , whose basis shall be the upper board , vvhich is commonly so large , that a less force may serve to break common bellows , then to raise so great a weight : but if they vvere made strong enough , and there vvere applied a sufficient force to lift so great a vveight as the newly mentioned pillar of the atmosphere , the sides might be disjoyn'd , how close and stanch soever the instrument vvere made . thus far one may argue upon the bare principle of the weight of the air , but taking in the spring of it too , i thought one might proceed so much further , that i ventur'd to foretell divers ingenious men , that if the pressure of the ambient air were taken off , not onely it would be easie to open the bellows in spite of their being carefully stopt at the nose , but that they would fly open as it were of their own accord , without the application of any external force at all . and 't was partly to justifie this prediction , as well as to make a trial , i thought more considerable , that we made the following experiment . we caus'd ( then ) to be made a pair of bellows , differing from ordinary ones in these particulars . first , that the boards were circular , ( and so without handles , ) and of about inches in diameter : . that there was no clack or valve : . that the nose was but an inch long , or less , ( being to be lengthned if occasion required vvith a pipe : ) . that the leather ( which vvas not spar'd , that the instrument might be the more capacious ) was not horny or very stiff , but limber . the reason of the first and third diversity was , that the bellows might be capable to be conveyed into our receiver ; ( for vvhich purpose also , if there had appear'd need , the nose might have been made in the uppermost of the two boards : ) the reason of the d variation was , that the instrument might be the more stanch : and of the th , that the bases of the bellows might ( as in organ-bellows ) be clapt closer together , and harbour less air in the wrinkles and cavity . so that when the bellows vvere opened to their full extent , by drawing up the upper basis at a button purposely made in the midst of it , the bellows look'd like a cylinder of or inches high ; upon which resemblance i take the liberty to call both the boards ( as geometricians do both the circular parts of a cylinder ) bases . but though these were made by an artificer , otherwise dexterous , yet it not being his trade to make bellows , nor any other mans in the town i then was in , he could not make them so tite , but that in spite of our oyling the leather , and choaking the seams with good cement , there was some litle and unperceived hole or cranny , whereby some air had passage when the nose was accurately stopt : but this was not so considerable , but that if we drew up the upper basis from the lower , the external air would on all sides press the leather inwards , and so make the shape of the instrument very far from being so cylindrical , as it would be if the nose were left open . wherefore concluding , that notwithstanding this imperfection the bellows would serve , though not for both the experiments i design'd , yet for one of them , we carefully stopt the nose , after we had approach'd the bases to one another , and conveying them into a large receiver , it quickly appear'd , when the pump was set on work , that at every exsuction of the incumbent air , the air harbour'd in the folds of the leather , and the rest of the litle cavitie that could not but be left between the bases , made the upper of those bases manifestly rise , though its weight ( because of the thickness and solidity of the wood ) would soon after depress it again , either by driving out some of the air at some place where the instrument was not sufficiently tite , or by making it as it were strain'd through the leather it self ; and if the pump were agitated somewhat faster than ordinary , the expansion of the internal air would be greater than could be rendred quite ineffectual by so small a leak , and the upper part of the bellows would be soon rais'd to a considerable height , as would appear more evidently if we hastily let in the external air , upon whose ingress the bases would be clapt together , and the upper of them a good vvay deprest . so that the imperfection of the bellows made the experiment rather more than less concluding ; for since there was no external force applied to open them , if notwithstanding that some of the included air could get out of thē , yet the spring of the internal air was strong enough to open the bellows when the ambient air was withdrawn , much more would the effect have been produc'd , if the bellows had been perfectly stanch . experiment xxxviii . about an attempt to examine the motions and sensibility of the cartesian materia subtilis , or the aether , with a pair of bellows ( made of a bladder ) in the exhausted receiver . i will not now discuss the controversie betwixt some of the modern atomists , and the cartesians ; the former of whom think , that betwixt the earth and the stars , and betwixt these themselves there are vast tracts of space that are empty , save where the beams of light do pass through them ; and the later of whom tell us , that the intervals betwixt the stars and planets ( among which the earth may perhaps be reckon'd ) are perfectly fill'd , but by a matter far subtiler than our air , which some call celestial , and others aether . i shall not , i say , engage in this controversie , but thus much seems evident , that if there be such a celestial matter , it must make up far the greatest part of the universe known to us . for the intersteller part of the world ( if i may so stile it ) bears so very great a proportion to the globes , and their atmospheres too , ( if other stars have any as well as the earth , ) that it is almost incomparably greater in respect of them , than all our atmosphere is in respect of the clouds , not to make the comparison between the sea and the fishes that swim in it . wherefore i thought it might very vvell deserve a heedful enquiry , whether we can by sensible experiments ( for i hear what has been attempted by speculative arguments ) discover any thing about the existence , or the qualifications of this so vast aether : and i hoped our curiosity might be somewhat assisted by our engine , if i could manage in it such a pair of bellows as i design'd . for i propos'd to my self to fasten a convenient weight to the upper basis , and clog the lower with another , great enough to keep it horizontal and immoveable , that when by the help of the turning-key , frequently above mention'd , the upper basis should be rais'd to its full height , the cavity of the bellows might be brought to its full dimensions . this done , i intended to exhaust the receiver , and consequently the thus open'd bellows with more than ordinary diligence , that so both the receiver and they might be carefully freed from air. after vvhich i purpos'd to let go the upper base of the bellows , that being hastily deprest by the incumbent weight , it might speedily enough fall down to the lower basis , and by so much , and so quickly lessening the cavity , might expell thence the matter ( if any were ) before contain'd in it , and that ( if it could by this way be done ) at the hole of a slender pipe , fasten'd either near the bottom of the bellows , or in the upper basis : against or over the orifice of which pipe there was to be plac'd at a convenient distance either a feather , or ( if that should prove too light ) the sail of a litle wind-mill made of cards , or some other light body , and fit to be put into motion by the impulse of any matter that should be forc'd out of the pipe. by this means it seem'd not improbable , that some such discovery might be made , as would not be altogether useless in our enquiry . for if notwithstanding the absence of the air , it should appear by the effects that a stream of other matter , capable to set visible bodies a moving , should issue out at the pipe of the comprest bellows ; it would also appear , that there may be a much subtiller body than common air , and as yet unobserv'd by the vacuists , or ( their adversaries ) the schools , that may even copiously be found in places deserted by that air ; and that it is not safe to conclude from the absence of the air in our receivers , and in the upper part of those tubes where the torricellian experiment is made , that there is no other body left but an absolute vacuity , or ( as the atomists call it ) a vacuū coacervatū . but if on the other side there should appear no motion at all to be produc'd , so much as in the feather , it seem'd that the vacuists might plausibly argue , that either the cavity of the bellows was absolutely empty , or else that it would be very difficult to prove by any sensible experiment that it was full , and , if by any other way of probation it be demonstrable , that it was replenish'd with aether , we that have not yet declar'd for any party , may by our experiment be taught to have no confident expectations of easily making it sensible by mechanical experiments ; and may also be inform'd , that t is really so subtle and yielding a matter , that does not either easily impell such light bodies as even feathers , or sensibly resist as does the air it self the motions of other bodies through it , and is able without resistance to make its passage through the pores of wood , and leather , and also of closer bodies , which we find not that the air doth in its natural or wonted state penetrate . to illustrate this last clause i shall adde , that to make the trial more accurate , i wav'd the use of other bellows , ( especially not having such as i desired , ) & caus'd a pair of small bellows to be made with a bladder , as a body , which some of our former experiments have evinc'd to be of so close a texture , that air will rather break it than passe through it : and that the bladder might no where loose its entireness by seams , we glued on the two bases , the one to the bottom , and the other to the opposite part of it , so that the neck came out at a hole purposely made for it ; in the upper basis , and into the neck it was easie to insert what pipe we thought fit , binding the neck very close to it on the outside . we had likewise thoughts to have another pair of tite bellows made with a very light clack in the lower basis , that by hastily drawing up the other basis , when the receiver and bellows were very carefully exhausted , we might see by the rest , as the lifting up of the clack , whether the subtle matter that was expell'd by the upper basis in its ascent , would , according to the modern doctrine of the circle made by moving bodies , be impell'd up or not . we also thought of placing the litle pipe of the bladder-bellows ( if i may so call them ) beneath the surface of water exquisitely freed from air , that we might see whither upon the depression of the bellows by the incumbent weight , when the receiver was carefully exhausted , there would be any thing expell'd at the pipe , that would produce bubbles in the liquor , wherein its orifice was immerst . to bring now our conjectures to some trial , we put into a capp'd receiver the bladder accommodated as before is mentioned , and though we could have wish'd it had been somewhat larger , because it contain'd but between half a pint and a pint , yet in regard it was fine and limber , and otherwise fit for our turn , we resolv'd to try how it would do ; and to depress the upper basis of these litle bellows the more easily and uniformly , we cover'd the round piece of pastboard , that made the upper basis , with a pewter-plate , ( with a hole in it for the neck of the bladder ; ) which nevertheless upon trial prov'd not ponderous enough , whereby we were oblig'd to assist it by laying on it a weight of lead . and to secure the above mentioned feather , ( which had a slender and flexible stem , and was left broad at one end , and fastned by cement at the other , so as to stand with its broad end at a convenient distance just over the orifice of the pipe , ) from being blown aside to either hand , we made it to move in a perpendicular slit in a piece of pastboard , that was fastned to one part of the upper basis , as that which the feather was glued to was to another part . these things being thus provided , the pump was set a work , and as the ambient air was from time to time withdrawn , so the air in the bladder expanded it self so strongly , as to lift up the metalline weight , and yet in part to sally out at the litle glass-pipe of our bellows , as appear'd by its blowing up the feather , and keeping it suspended till the spring of the air in the bladder was too far weakned to continue to do as it had done . in the mean time we did now and then , by the help of a string fasten'd to the turning-key , and the upper basis of the bellows , let down that basis a litle , to observe how upon its sinking the blast against the feather would decrease , as the receiver was further and further exhausted . and when we judg'd it to be sufficiently freed from air , we then let down the weight , but could not perceive that by shutting of the bellows the feather was at all blown up , as it had been wont to be , though the upper basis were more than usually deprest . and yet it seems somewhat odd , that when , for curiosity , in order to a further trial , the weight was drawn up again , as the upper basis was rais'd from the lower , the sides of the bladder were sensibly ( though not very much ) prest , or drawn inwards . the bellows being thus opened , we let down the upper basis again , but could not perceive that any blast was produc'd ; for though the feather , that lay just over and near the orifice of the litle glass pipe , had some motion , yet this seem'd plainly to be but a shaking and almost vibrating motion ( to the right and left hand , ) which it was put into by the upper basis , which the string kept from a smooth and uniform descent ; but not to proceed from any blast issuing out of the cavity of the bladder . and for further satisfaction we caus'd some air to be let into the receiver , because there was a possibility , that unawares to us the slender pipe might by some accident be choak'd ; but though upon the return of the air into the receiver , the bases of the bellows were prest closer together , yet it seem'd that , according to our expectation , some litle air got through the pipe into the cavity of the bladder : for when we began to vvithdraw again the air we had let into the receiver , the bladder began to swell again , and upon our letting down the weight , to blow up and keep up the feather , as had been done before the receiver had been so well exhausted . what conjecture the opening and shutting of our litle bellows , more than once or twice , without procducing any blast sensible by the raising of the feather , gave some of the by-standers , may be easily guess'd by the preamble of this experiment ; but whilst i was endeavouring to prosecute it for my own further information , a mischance that befell the instrument , kept me from giving my self the desir'd satisfaction . experiment xxxix . about a further attempt to prosecute the inquiry propos'd in the foregoing experiment . considering with my self , that by the help of some contrivances not difficult , a syringe might be made to serve , as far as our present occasion required , in stead of a pair of bellows ; i thought it would not be improper to try a differing , and , in some regards , a better way to prosecute an attempt , which seem'd to me to deserve our curiosity . i caus'd then to be made , for the formerly mentioned syringe , in stead of its streight pipe , a crooked one ; whose shorter leg was parallel to the longer . and this pipe was for greater closeness , after 't was screw'd on carefully , fastned with cement to the barrel ; and because the brass-pipe could scarce be made small enough , we caus'd a short and very slender pipe of glass to be put into the orifice of the shorter leg , and diligently fasten'd to it with close cement . then we caus'd the sucker ( by the help of oyl , water , and moving it up and down ) to be made to go as smoothly as might be , without lessening the stanchness of the syringe . after this , there was fastned to the handle of the rammer a weight , made in the form of a ring , or hoop , which by reason of its figure might be suspended from the newly mention'd handle of the rammer , and hang loose on the outside of the cylinder , and which both by its figure and its weight might evenly and swiftly enough depress the sucker , when that being drawn up the weight should be let go . this syringe thus furnished , was fastned to a broad and heavy pedestal , to keep it in its vertical posture , and to hinder it from tottering , notwithstanding the weight that clogg'd it . and besides all these things , there was taken a feather , which was about two inches long , and of which there was left at the end a piece about the breadth of a mans thumb-naile , ( the rest on either side of the slender stalk ( if i may so call it ) being stript off ) to cover the hole of the slender glass pipe of the syringe ; for which purpose the other extreme of it was so fastned with cement to the lower part of the syring , ( or to its pedestal , ) that the broad end of the feather was plac'd ( as the other feather was in the foregoing experiment ) just over the litle orifice of the glass , at such a convenient distance , that when the sucker was a litle ( though but very litle ) drawn up and let go again , the weight would depress it fast enough to blow up the broad part of the feather , as high as was permitted by the resistance of the stalk , ( and that was a good way , ) the spring of which would presently restore the whole feather to its former position . all these things being done , and the handle of the rammer being tied to the turning-key of a capp'd receiver , the syringe and its pedestal were inclosed in a capacious receiver , ( for none but such a one could contain them , and give scope for the rammers motions , ) and the pump being set on worke , we did , after some quantity of air was drawn out , raise the sucker a litle by the help of the turning-key , and then turning the same key the contrary way we suffer'd the weight to depress the sucker , that we might see at what rate the feather would be blown up ; and finding that it was impell'd forceably enough , we caus'd the pumping to be so continued , that a pretty many pauses were made , during each of which we rais'd and depress'd the sucker as before , and had the opportunity to observe , that as the receiver was more and more exhausted of the air , so the feather was less and less briskly driven up , till at length , when the receiver was well emptied , the usual elevations and depressions of the sucker would not blow it up at all that i could perceive , though they were far more frequently repeated than ever before ; nor was i content to look heedfully my self , but i made one whom i had often imploy'd about pneumatical experiments to watch attentively , whilst i drew up , and let down the sucker , but he affirm'd that he could not discern the least beginning of ascension in the feather . and indeed to both of us it seem'd , that the litle and inconsiderable motion that was sometimes ( not alwayes ) to be discern'd in the feather , proceeded not from any thing that issued out of the pipe , but from some litle shake , which t was difficult not to give the syringe and pedestal , by the raising and depressing of the sucker . and that which made our phaenomenon the more considerable , was , that the weight that carried down the sucker being still the same , and the motions of the turning-key being easie to be made equal at several times , there seem'd no reason to suspect that contingencies did much ( if at all ) favour the success ; but there hapned a thing , which did manifestly enough disfavour it . for i remember , that before the syringe was put into the receiver , when we were trying how the weight would depress it , and it was thought that though the weight were conveniently shap'd , yet it was a litle of the least ; i would not alter it , but foretold , that when the air in the cavity of the syringe ( that now resisted the quickness of its descent , because so much air could not easily and nimbly get out at so small a pipe ) should be exhausted with the other air of the receiver , the elevated sucker would fall down more easily , which he , that was imploy'd to manage the syringe whilst i watch'd the feather , affirm'd himself afterwards to observe very evidently . so that when the receiver was exhausted , if there had been in the cavity of the syringe a matter as fit as air to make a wind of , the blast ought to have been greater , because the celerity that the sucker was deprest with was so . after we had long enough tried in vain to raise the feather , i order'd some air to be let into the receiver ; and though when the admitted air was but very litle , the motions of the sucker had scarce if at all any sensible operation upon the feather , yet when the quantity of air began to be somewhat considerable , the feather began to be a litle mov'd upwards , and so by letting in air not all at once but more and more from time to time , and by moving the sucker up and down in the intervals of those times of admission , we had the opportunity to observe , that as the receiver had more air in it , the feather would be more briskly blown up . but not content with a single tryal of an experiment of this consequence , we caused the receiver to be again exhausted , and prosecuted the tryal with the like success as before , onely this one circumstance , that we added for confirmation , may be befit to be here taken notice of . having , after the receiver was exhausted , drawn up and let fall the sucker divers times ineffectually ; though hitherto we had not usually rais'd it any higher at a time , than we could by one turn of the hand , both because we could not so conveniently raise it higher by the hand alone , and because we thought it unnecessary , since that height suffic'd to make the air briskly toss up the feather ; yet ex abundanti we novv took an instrument that was pretty long and fit so to take hold on the turning-key , that we could easily raise the sucker between two and three inches ( by our aestimate ) at a time , and nimbly depress it again ; and for all this , which would much have increas'd the blast , if there had been a matter fit for it in the cavity of the syringe , we could not sensibly blow up the feather , till we had let a litle air into the receiver . to be able to make an aestimate of the quantity of air pump'd out , or let in , when the feather vvas strongly or faintly , or not at all rais'd by the fall of the sucker ; vve took off the receiver , and convey'd a gage into it , but though for a vvhile vve made some use of our gage , yet a mischance befalling it before the operation was quite ended , i shall forbear to adde any thing concerning that tryal , and proceed to say something of another attempt , wherein though i foresaw and met with such difficulties , as kept me from doing altogether what i desired , yet the success being almost as good as could be expected , i shall venture to acquaint your lordship with the tryal , which was this . in stead of the hitherto imploy'd pipe of brass , there was well fastned ( with cement ) to the syringe a pipe of glass , whose figure differ'd from that of the other in this particular , that the shorter ( or remoter ) leg of our new pipe , after it had for a while been carried parallel to the other leg , was bent off so , that above an inch and a half of it tended downwards , that the orifice of it might be immerst into water contain'd in a small open jarr . the design of which contrivance was , that when the receiver should be well exhausted , we might ( according to what i told your lordship vvas at first design'd ) try vvhether by the raising and depressing of the sucker any such matter would be driven out at the nose of the pipe , as would produce bubbles in the incumbent water , which , air ( though highly rarefied , perhaps to some hundreds of times beyond its wonted dimensions , ) is capable of doing . and i choose to imploy rather water than quick-silver , because though by using the later i might hope to be less troubled with bubbles , yet the ponderousness and opacity of it seem'd to outweigh that convenience . i need not tell your lordship , that in other respects this experiment was made like the former , so that i shall mention onely its peculiarities , which were , that as the air was pump'd out of the receiver , that in the glass pipe made its way through the water in bubbles , and a litle air having once by a small leak got in , and forc'd some of the water out of the jarr into the pipe , when the receiver was again vvell emptied , both that water and even the litle quantity of stagnant water , that was contain'd in the immerst part of the pipe , produc'd so many bubbles of several sizes , as quite disturb'd our observations . wherefore we let alone the receiver , exhausted as it was , for or hours , to give the water time to be freed from air , and then causing what air might have stolen in to be again pump'd out , till we had perceiv'd by the gage that the receiver was well exhausted , we caus'd the sucker ( of the syringe ) to be rais'd and deprest diverse times , and though even then a bubble vvould now and then make our observations troublesome , and less certain , yet it seem'd to us , that when we were not thus confounded , we sometimes observed that the elevation and fall of the sucker , though reiterated , did not drive out at the pipe any thing that made any discernable bubbles in the incumbent water ; for though there would appear now and then some small bubbles on the surface of the water , yet i could not perceive that the matter that made them , issued out at the pipe ; and some of them manifestly proceeded from aerial particles , till then lurking in the water , as i concluded from the place and time of their rising . but this non-eruption of bubles at the nose of the pipe , vvas not that which gave me the most of satisfaction . for at length both i and another had the opportunity to observe the water in the immerst part of the pipe , which was very slender , to be about an inch higher than the rest of the stagnant water , and to continue at that height or place in the pipe , though the sucker vvere divers times together rais'd and depress'd by guess between and three inches at a time . which seem'd to argue , either that there was a vacuum in the cavity of the syringe , or else that if it were full of aether , that body vvas so subtle , that the impulse it received from the falling sucker vvould not make it displeace a very litle thread ( perhaps not exceeding a grain in weight ) of water that vvas in the slender pipe , though it appear'd by the bubbles , that sometimes disclos'd themselves in the water , after the receiver had been exhausted , that far more water vvould be displac'd and carried up by a small bubble consisting of such rarified air , that according to my aestimate the aerial particles of it did not , before the pump vvas begun to be set on vvork , take up in the water a five-hundredth part of the quantity of a pins head . but whilst we were considering what to do further in our tryal , a litle air , that strain'd in at some small undiscoverable leak , drove the water into the emptied part of the pipe , and put an end for that time to our tryal , which had been too toylsome to invite us then to reiterate it . i had indeed thoughts of prosecuting the enquiry , by dropping from the top of the exhausted receiver light bodies conveniently shap'd , to be turn'd round , or otherwise put out of their simplest motion of descent , if they met with any resistance in their fall ; and by making such bodies move horizontally and otherwise in the receiver , as vvould probably discover whither they were assisted by the medium : and other contrivances and wayes i had in my thoughts , whereby to prosecute our enquiry , but vvanting time for other experiments , i could not spare so much as was necessary to exhaust large receivers so diligently , as such nice trials would exact ; and therefore i resolv'd to desist , till i had more leisure than i then had , ( or have since been master of . ) in the interim , thus much we seem to have already discovered by our past tryals , that if when our vessels are very diligently freed from air , they are full of aether , that aether is such a body , as will not be made sensibly to move a light feather by such an impulse as would make the air manifestly move it , not onely whilst t is no thinner than common air , but when t is very highly rarified , ( which , if i mistake not , it was in our experiment so much , as to be brought to take up above an hundred times more room than before . ) and one thing more we gain'd by the tryal made with water , namely a clear confirmation of what i deliver'd in the th experiment , about the cause of the suction that is made by syringes ; for your lordship may remember , that at the close of the experiment we have all this while been reciting , i observ'd , that when the external air was so very well withdrawn , the pulling up of the sucker would not make the stagnant water , that the pipe of the syringe was immerst in , to ascend one inch , or so much as the tenth part of it . experiment xl. about the falling , in the exhausted receiver , of a light body , fitted to have its motion visibly varied by a small resistance of the air. partly to try whether in the space deserted by the air , drawn out of our receivers , there would be any thing more fit to resist the motion of other light bodies through it , than in the former experiment we found it to impell them into motion ; and partly for another purpose to be mention'd by and by , we made the following tryals . we took a receiver , which , though less tall than we would have had , was the longest we could procure : and that we might be able , not so properly to let down as , to let fall a body in it , we so fastned a small pair of tobacco-tongs to the inside of the receivers brass-cover , that by moving the turning-key , we might by a string tied to one part of them , open the tongs , which else their own spring would keep shut . this being done , the next thing was to provide a body , which vvould not fall down like a stone , or another dead weight through the air , but would in the manner of its descent shew , that its motion was somewhat resisted by the air ; vvherefore that vve might have a body that vvould be turn'd about horizontally ( as it were ) in its fall , we thought fit to joyn cross-wise four broad and light feathers ( each about an inch long ) at their quils with a litle cement , into vvhich vve also stuck perpendicularly a small label of paper , about an th of an inch in breadth , and somewhat more in height , by vvhich the tongues might take hold of our light instrument vvithout touching the cement , which else might stick to them . by the help of this small piece of paper , the litle instrument , of vvhich it made a part , vvas so taken hold of by the tongs , that it hung as horizontal as such a thing could well be plac'd : and then the receiver being cemented on to the engine , the pump vvas diligently ply'd , till it appear'd by a gage , which had been conveyed in , that the reciver had been carefully exhausted : lastly , our eyes being attentively fix'd upon the connected feathers , the tongs were by the help of the turning-key open'd , and the litle instrument let fall , which , though in the air it had made some turns in its descent from the same height it now fell from , yet now it descended like a dead weight , without being perceiv'd by any of us to make so much as one turn , or a part of it : notwithstanding which i did , for greater security , cause the receiver to be taken off , and put on again , after the feathers were taken hold of by the tongs , whence being let fall in the receiver unexhausted , they made some turns in their descent , as they also did being a second time let fall after the same manner . but when after this , the feathers being plac'd as before , we repeated the experiment by carefully pumping out the air , neither i nor any of the by-standers could perceive any thing of turning in the descent of the feathers ; and yet for further security we let them fall twice more in the unexhausted receiver , and found them to turn in falling as before ; whereas when we did a d time let them fall in the well exhausted receiver , they fell after the same manner as they had done formerly , when the air , that vvould by its resistance have turn'd them round , vvas remov'd out of their vvay . note . though ( as i intimated above ) the glass , vvherein this experiment was made , were nothing near so tall as i would have had it , yet it was taller than any of our ordinary receivers , it being in height about inches . . one that had had more leisure and conveniency , might have made a more commodious instrument than that we made use of : for being accidentally visited by that sagacious mathematician d r wren , and speaking to him of this matter , he was pleas'd with great dexterity as well as readiness to make me a little instrument of paper , on which , when t was let fall , the resistance of the air had so manifest an operation , that i should have made use of it in our experiment , had it not been casually lost when the ingenious maker was gone out of these parts . . though i have but briefly related our having so order'd the matter , that we could conveniently let fall a body in the receiver when very well exhausted , yet to contrive and put in practice what was necessary to perform this , was not so very easie , and it would be difficult to describe it circumstantially without very many words ; for which reason i forbear an account , that would prove too tedious to us both . . what has been hitherto related , was done in prosecution of but one of the two designs i aim'd at in the foregoing contrivance , by which i intended , if i could have procured a receiver tall enough , to try whether bodies ( some very light , and some heavier ) being let fall when the air was very diligently pump'd out , would not descend somewhat faster than if the receiver were full of air. but though i had provided a pendulum that vibrated quarters of seconds , yet the glass being no higher than it was , the descent even of our feathers took up so litle time , that even this pendulum was of no use ; onely it seem'd to all of us that were present at making the above recited tryals , that when the feathers were let fall at such times as the air ( that would have turn'd them round in their descent ) was removed , they came to the bottom sensibly sooner than at other times . but when we shall have opportunity to repeat the experiment in taller glasses , and to make some variation of it , i hope to be able to give your lordship a fuller satisfaction about this particular . and in the mean while i shall forbear to examine whether the air might somewhat retard the descent of the feathers upon some other account , or meerly upon that of its being a medium not quite devoid of gravity . annotations . . but here i must be so sincere as to inform your lordship , that this th experiment seem'd not to prove so much as did the foregoing made with the syringe : for being suspicious that , to make the feathered body above mentioned turn in its fall , there would need a resistance not altogether inconsiderable , i caus'd the experiment to be repeated , when the receiver was by our aestimate ( which was not made at random neither ) litle or nothing more than half exhausted , and yet the remaining air was too far rarified to make the falling body manifestly turn . . and yet perchance it would have hapned otherwise , if the receiver had been tall enough ; which though i had not then leasure and conveniency to make it , yet it will not be amiss to let your lorship know by what means we did , that it might be somewhat fit to make the recited experiment and some others , bring it to the height it had , which did considerably exceed that of the tallest glass we could then procure . to lengthen our receiver therefore , we thought fit to try , whether we could not close enough fasten to the bottom of it , with very good cement a cylindrical pipe of laton , whose upper orifice should have neer the same breadth with the bottom of the glass . and though this contrivance seem'd liable to a couple of not mean difficulties ; the one , that the laton being every where bended , and in some places necessary to be souder'd , it would be very hard ( as indeed we found it ) to avoid some small cracks and leaks : and the other , that if the metalline pipe were wide enough , so great and heavy a pillar of the atmosphere would come to bear against it , as to press it inwards , if not also to break it ; yet we hoped we should be able to obviate both of these inconveniences . against the first of which our remedy was , to coat over very carefully the whole pipe with the same close cement , wherewith we fastned it to the glass receiver . and against the second , we provided a litle frame consisting of divers small iron bars fastned together ; which frame ( though t were not too wide to go into the cylinder of laton , yet it ) was wide enough to be so neer it on the inside , that ( though the weight of the atmosphere should , as we feared , press the laton so as to make it yield inward , yet ) it could make it bend no further than the iron-frame would permit ; which was not far enough to spoile either the receiver or the experiment . and this not unpleasant phaenomenon would somewhat surprise unaccustomed spectators , that when after the receiver had been very well exhausted , the external air was permitted to return , there would be heard during some time , from the metalline part of the receiver , divers sounds brisk enough , which would make an odd cracking noise proceeding from the laton-plate , which having been forceably , though but slowly , bent inwards by the predominant pressure of the atmosphere , was now assisted by the pressure of the returning air , to regain its former figure . and as i thought not fit to omit this circumstance , because it confirms the practicableness of the remedy propos'd against the d inconvenience ; so i thought fit to mention this way of enlarging and heightning receivers , because what we have related seems to give grounds of hoping that this contrivance may be made good use of in divers other tryals , and particularly in attempts to make receivers capacious enough to contain larger animals , and perhaps even a boy , or a man. in order to some of which purposes we indeavoured to get an improvement made of our metalline cylinder by additional contrivances ; but could not ( where we then were ) get artificers , that would perform what was directed . experiment xli . about the propagation of sounds in the exhausted receiver . to make some further observation than is mention'd in the * publish'd experiments , about the production and conveying of sounds in a glass whence the air is drawn out , we imploy'd a contrivance , of which ( because we make use of it in divers other experiments ) it will be requisite to give your lordship here some short description . we caus'd to be made at the turners a cylinder of box , or the like close and firme wood , and of a length suitable to that of the receiver it was to be imploy'd in . out of the lower basis of this cylinder ( vvhich might be about an inch and a half in diameter ) there came a smaller cylinder or axle-tree not a quarter so thick as the other , and less than an inch long : this vvas turn'd very true , that it might move to & fro ( or , as the tradesmen call it , ride ) very smoothly in a litle ferrule or ring of brass , that was by the same turner made for it in the midst of the fixt trencher , ( as we call a piece of solid wood shap'd like a milstone , ) being or inches ( more or less according to the wideness of the receiver ) in breadth , and between one and two in thickness ; and in a large and round groove , or gutter , purposely made in the lower part of this trencher , i caus'd as much lead as vvould fill it up to be plac'd and fasten'd , that it might keep the trencher from being easily mov'd out of its place or posture , and in the upper part of this trencher it vvas intended that holes should be made at such places as should be thought fit , to place bodies at several distances as occasion should require . the upper basis of the cylinder had also coming out of the midst of it another axletree , but wider than the former , that , into a cavity made in it , it might receive the lower end of the turning-key divers times already mentioned , to which t was to be fastned by a slender peg of brass , thrust through two correspondent holes , the one made in the key , and the other in the newly mentioned socket ( if i may so call it ) of the axletree . besides all vvhich , there were divers horizontal perforations bored here and there in the pillar it self , to which this axis belong'd , vvhich pillar we shall to avoid ambiguity call the vertical cylinder . the general use of this contrivance ( whose other parts need not to be mentioned before the experiments where they are imploy'd ) is , that the end of the turning-key being put into the socket , and the lower axis of the vertical cylinder into the trencher , by the motion of the key a body fasten'd at one of the holes to the cylinder may be approach'd too , or remov'd from , or made to rub or strike against another body fastned in a convenient posture to the upper part of the trencher . to come now to our tryal about sounds , vve caus'd a hand-bell ( vvhose handle and clapper were taken away ) to be so fastned to a strng wire , that , one end of the wire being made fast in the trencher , the other end , vvhich vvas purposely bent downwards , took hold of the bell. in another hole , made in the circumference of the same trencher , vvas vvedg'd in ( vvith a wooden peg ) a steel-spring , to whose upper part was tied a gad of iron or steel , less than an inch long , but of a pretty thickness . the length of this spring was such , as to make the upper part of the hammer ( if i may so call the piece of iron ) of the same height with the bell , and the distance of the spring from the bell was such , that when it was forc'd back the other way , it might at its return make the hammer strike briskly upon the outside of the bell. the trencher being thus furnisht and plac'd in a capp'd receiver , ( as you know , for brevity sake , we use to call one that is fitted with one or other of the brass covers , often mentioned already , ) the air was diligently pump'd out ; and then , by the help of the turning-key , the vertical cylinder was made to go round , by which means as often as either of a couple of stiff wires , or small pegs , that were fastned at right angles into holes , made not far from the bottom of the cylinder , pass'd ( under the bell , and ) by the lately mentioned spring ; they forceably did in their passage bend it from the bell , by which means , as soon as the wire was gone by , and the spring ceas'd to be press'd , it would fly back with violence , enough to make the hammer give a smart stroak upon the bell. and by this means we could both continue the experiment at discretion , and make the percussions more equally strong than it would otherwise have been easie to do . the event of our tryal was ; that , when the receiver was vvell emptied , it sometimes seem'd doubtful , especially to some of the by-standers , whether any sound were produc'd or no ; but to me for the most part it seem'd , that after much attention i heard a sound , that i could but just hear ; and yet , vvhich is odd , me thought it had somewhat of the nature of shrilness in it , but seem'd ( which is not strange ) to come from a good way off . whether the often turning of the cylindrical key kept the receiver from being so stanch as else it vvould have been , upon vvhich score some litle air might insinuate it self , i shall not positively determine : but to discover vvhat interest the presence or the absence of the air might have in the loudness or lowness of the sound , i caus'd the air to be let into the receiver , not all at once but at several times , with competent intervals between them ; by which expedient it was easie to observe , that the vertical cylinder being still made to go round , when a litle air vvas let in , the stroak of the hammer upon the bell ( that before could now and then not be heard , and for the most part be but very scarcely heard ) began to be easily heard . and when a litle more air was let in , the sound grew more and more audible , and so increased , till the receiver was again replenished with air ; though even then ( that we omit not that phaenomenon ) the sound was observ'd to be much less loud than when the receiver was not interpos'd between the bell and the ear. and whereas in the already publish'd physico-mechanical experiments i acquainted your lordship with what i observ'd about the sound of an ordinary watch in the exhausted receiver , i shall now adde , that that experiment was repeated not long since , with the addition of suspending in the receiver a watch , with a good alarum , which was purposely so set , that it might , before it should begin to ring , give us time to cement on the receiver very carefully , exhaust it very diligently , and settle our selves in a silent and attentive posture . and to make this experiment in some respect more accurate than the others we made of sounds , we secur'd our selves against any leaking at the top , by imploying a receiver that was made all of one piece of glass , ( and consequently had no cover cemented on to it , ) being furnish'd onely within ( when 't was first blown ) with a glass-knob or button , to which a string might be tied . and because it might be suspected , that if the watch were suspended by its own silver chain , the tremulous motion of its sounding bell might be propagated by that metalline chain to the upper part of the glass ; to obviate this as well as we could , we hung the watch , not by its chain , but a very slender thread , whose upper end was fastned to the newly mentioned glass-button . these things being done , and the air being carefully pump'd out , we silently expected the time when the alarum should begin to ring , which 't was easie to know by the help of our other watches ; but not hearing any noise so soon as we expected , it would perhaps have been doubted whether the watch continued going , if for prevention we had not order'd the matter so , that we could discern it did not stand still . wherefore i desir'd an ingenious gentleman to hold his ear just over the button , at which the watch was suspended , and to hold it also very near to the receiver , upon which he told us that he could perceive , and but just perceive something of sound , that seem'd to come from far ; though neither we that listned very attentively near other parts of the receiver , nor he , if his ears were no more advantaged in point of position than ours , were satisfied that we heard the watch at all . wherefore ordering some air to be let in , we did by the help of attention begin to hear the alarum ; whose sound was odd enough , and , by returning the stop-cock to keep any more air from getting in , we kept the sound thus low for a pretty while , after which a little more air , that was permitted to enter , made it become more audible ; and when the air was yet more freely admitted , the by standers could plainly hear the noise of the yet continuing alarum at a considerable distance from the receiver . from what has hitherto been related we may learn what is to be thought of what is delivered by the learned mersennus , in that book of his harmonicks , where he makes this to be the first proposition . sonus à campanis , vel aliis corporibus non solùm producitur in illo vacuo ( quicquid tandem illud sit , ) quod fit in tubis hydrargyro plenis , posteaque depletis , sed etiam idem acumen , quod in aere libero vel clauso penitus observatur & auditur . for the proof of which assertion , not long after , he speaks thus : porro variis tubis , quorum extremis lagenae vitreae adglutinantur , observari campanas in illo vacuo appensas , propriisque malleis percussas idem penitus acumen retinere , quod in aere libero habent : atque soni magnitudinem ei sono , qui fit in aere quem tubus clausus includit , nihil cedere . but though our experiments sufficiently manifest that the presence or absence of the common air is of no small importance as to the conveying of sounds , and that the interposition of glass may sensibly weaken them ; yet so diligent and faithful a writer as mersennus deserves to be favourably treated : and therefore i shall represent on his behalf , that what he sayes may well enough have been true , as far as could be gathered from the tryals he made . for first , t is no easie matter , especially for those that have not peculiar and very close cements , to keep the air quite out for any considerable time in vessels consisting of divers pieces , such as he appears to have made use of . and next , the bigness of the bell in reference to the capacity of the exhausted glass , and the thickness of the glass , and the manner whereby the bell was fastned to the inside of the glass , and the hammer or clapper was made to strike , may much vary the effect of the tryal , for reasons easie to be gather'd out of the past discourse , and therefore not needful to be here insisted on . and upon this account we chose to make our experiment , with sounds that should not be strong or loud , and to produce them after such a manner , as that as litle shaking as could be might be given by the sounding body to the glass 't was included in . the proposal made by the same mersennus , to have those that have industry enough , try whether a bag-pipe will be made to afford the same sound as in the open air , in such vessels as he used for his bels , though he seems to think it would succeed , is that which your lordship will not , i presume , sollicite me to make tryal of , if you remember what is related in the almost immediately foregoing experiments , shewing , that we could make nothing come out of the cavity of a pair of bellows , that had force enough to blow away a feather , when that cavity was freed from air ; as the bagpipe would be by the same operation , that empties the glass that contains it , or else the sound would not be made in such a vacuum as the scope of the experiment requires . if i had had conveniency , i would have made some tryals by conveying a small string'd instrument ( perhaps some such as they commonly call a kit ) exactly tun'd , into a large receiver , and then upon briskly striking the string of a bigger instrument , ( tuned , as they speak , to an unison to ( or with ) that of the smaller instrument ) i should have taken notice , whether the sound would have been so uniformly propagated , notwithstanding the interposition of the glass receiver , as sensibly to shake the included string ; in order to the discerning of which , a bended piece of straw , or feather , or some such light body , was to be hors'd upon the string to be shaken . i also intended , in case the string were made to move , to make the like tryal after the receiver was diligently exhausted . and lastly i design'd to try , whether two unison strings of the same instruments , or of a couple to be plac'd in the same receiver , would , when the air ( which is the usual medium of sounds ) was well pump'd out , yet maintain such a sympathy ( as t is call'd , ) that upon the motion of the one , the other would also be made to stir : which tryals may be varied , by imploying for the external instrument another in stead of a stringed one . and because contraries ( as is vulgarly noted ) serve to illustrate each other , i thought to subjoyn , to the tryals above related , about the propagation of sounds in a thinner medium than the air , some observations about the conveyance of them through that thicker medium , water ; but having unluckily mislaid my notes upon that subject , i cannot at present acquaint your lordship with what i intended , but must defer the doing it , till i shall have recovered them. experiment xlii . about the breaking of a glass-drop in an exhausted receiver . you know , that among the causes that have been propos'd of the strange flying of a glass-drop into a multitude of pieces , when the slender stem of it comes to be broken off , one of the least improbable was taken from the pressure of the air : as if that within the poreous ( and as 't were honey-comb'd ) inside of the glass , being highly rarified when the drop of melted glass fell into the water at its first formation , it was forc'd to continue in that praeternatural state of expansion by the hardness and closeness of the external case of glass , that inclos'd the pithlike part ( if i may so call it ; ) so that upon the breaking off a part of this solid case at the stem , the external air gaining access , and finding in the spungy part very litle resistance from the highly rarified and conse quently weaken'd air included there , rushes in with such violence , as to shiver the glass-drop into a multitude of pieces . i shall not now trouble your lordship with the mention of what may be alleadg'd to question this hypothesis , especially if it be compared with that accurate account of the phaenomena of such glass-drops , which was sometime since presented to the society by that great ornament of it , s r robert moray . but i shall onely say in this place , that when i consider'd , that if the dissilition of the glass would succeed when the air was pump'd out of it , it would be hard to ascribe that effect to the irruption of the external air , i thought fit to try what would happen , if a glass-drop were broken in our exhausted receiver . and accordingly did , though not without some difficulty , so order the matter , that the blunter part of the glass-drop was fastned to a stable body ( convey'd into the receiver , ) and the crooked stem was tyed to one end of a string , whose other end was fastned to the turning-key ; by which means , when the air had been diligently pump'd out , the stem was ( by shortning the string ) broken off , and the glass drop was shatter'd into a thousand pieces . this experiment was long after repeated with the like success , and having at that time no gage to try how far the air had been drawn out , we let the external air impell up the water out of the pump into the receiver , and thereby found , that that vessel had not been negligently exhausted . experiment xliii . about the production of light in the exhausted receiver . i presume , i need not put your lordship in mind , that divers attempts were made to try , whether either a flame , or kindled coals would be made to continue for sometime burning in our receiver : but those tryals making it evident , that it would be either impossible , or very difficult to produce any durable light , without the presence of the air , by the burning of bodies ; i thought it not amiss , considering the nobleness of light , to make trial , whether it might be otherwise produc'd in our exhausted receiver ; since whether or no the attempts should prove successful , the event would probably be instructive . for as t is the property of light , when t is produc'd , to be discoverable by it self ; so in such a tryal as we intended , it would teach something concerning light , to find that the absence of the air would or would not hinder it from being produc'd . in prosecution of this design , knowing that hard sugar , being nimbly scrap'd with a knife , will afford a sparkling light , so that now & then one would think that sparks of fire fly from it ; we caus'd a good lump of hard loaf-sugar to be conveniently and firmly placed in the cavity of our capp'd receiver , and to the vertical cylinder formerly mentioned we caus'd to be fastned some pieces of a steel-spring , which being not very thick , might in their passage along the sugar , grate , or rub forceably against it , and then the receiver being diligently exhausted in the night-time , and in a dark room , the vertical cylinder ( whose lower axis was inserted into the often mentioned trencher ) was made for a pretty while to move round by the help of the turning-key , manag'd by a hand steady and strong enough . by which means the irons that came out of the vertical cylinder , making in their passage vigorous impressions upon the sugar that stood somewhat in their way , there were manifestly produc'd a good number of litle flashes , and sometimes too , though not frequently , there seem'd to be struck off litle sparks of fire . experiment xliv . about the production of a kind of halo , and colours in the exhausted receiver . vve took a large inverted cucurbite for a receiver , which being so well wip'd both within and without as to be very clear , allow'd me to observe , and to make others do so too , that when the pump began to be set a work , if i caus'd a pretty large candle to be held on the other side of the glass , upon the turning of the stop-cock to let the air out of the receiver into the cylinder , the glass would seem to be full of fumes , and there would appear about the flame of the candle , seen through them , a kind of halo , that at first commonly was between blew and green , and after some sucks would be of a reddish or orange colour , and both very vivid . the production of this meteor ( if i may so call it ) was , according to my conjecture , made on some such score as this . that the cement being somewhat soft and new ( as is convenient for this experiment ) abounds with turpentine , and having a litle ( as well to fasten on the receiver , as for the other purpose ) apply'd to it a hot iron , whereby the cement was both softned and heated , it seem'd rational to expect , that upon the withdrawing of the air in the receiver , the aerial particles in the cement , freed from their former pressure , would extricate themselves , and with the looser steams of the turpentine and perhaps of the bees-wax would with a kind of explosion expand themselves in the receiver , and by their interposition between the light and the eye exhibit those delightful colours we had seen . to confirme which , i afterwards found , that by watchfully observing it i could plainly enough perceive the colouring steams , just upon the turning of the stopcock , to fly up from the cement towards the top of the glass ; and if we continued pumping , the receiver would grow clearer , and the colours more dilute , ( till we had occasion to put on the receiver , and heat the cement afresh : ) of which the reason might be , partly that the aerial and volatile particles of the upper part of the cement did in that tract of time spend themselves more and more ; and partly , because the agitation they receiv'd from the heat communicated by the iron did continually decay . not to mention , that when the receiver is more exhausted , the want of air makes it more difficult for steams to be supported , and as it were swim up and down in it . but for farther confirmation , i caus'd some cement to be put into a small crucible , warm enough to melt it ; and conveying this into a clear receiver of a convenient shape and size , i caus'd the pump to be set a work ; whereupon it appear'd manifestly enough , that upon the opening of the stop-cock to let out the air , the steams would copiously be thrown about from the crucible into the capacity of the receiver , and would , after having a litle play'd there , fall down again . but in these apparitions the vividness , and sometimes the kind of the exhibited colours seem'd much to depend upon divers circumstances , such as the degrees of heat , the bigness and shape of the receiver , the quantity of air that yet remain'd unpump'd out , and the nature of the cement its self ; which last particular i the rather mention , because , though i were hinder'd from doing it , i had thoughts to try a suspicion i had , that by varying the materials expos'd to this kind of operation , some pretty variety might be made in the phaenomena of the experiment . whether or no the apparition of whiteness , or light , that we sometimes hapned to take notice of divers years agoe , and have mentioned in the already * publish'd part of our physico-mechanical experiments , may be partly ( though not entirely ) referr'd to some of the cements i then imploy'd , differing from those i now use most , and to the unheeded temper of those cements , as to warmth , and degrees of softness , is a doubt that further observation may possibly enable us to determine . experiment xlv . about the production of heat by attrition in the exhausted receiver . the opinion that ascribes the incalescence of solid bodies , struck or rubb'd hard against one another to the attrition or vehement agitation of the intercepted air , is famous and received enough to seem worthy of a particular examination . but i confess to your lordship , that t was not any thing relating to this opinion that chiefly induc'd me to make the experiment i am now about to give an account of ; for i thought it might be usefull to more purposes than one , to be able to produce by attrition a somewhat durable heat even in our exhausted receiver : and therefore though 't were easie to foresee , that it would prove no easie task , yet we thought fit to attempt it in spight of the difficulties met with at our first tryal . in what way and with what success we afterwards made this attempt , i now proceed to relate . cross the stable trencher , formerly often mentioned , there was fastned a pretty strong spring of steel or iron , shap'd almost like the lathe of a cross-bow , and to the midst of this spring was strongly fastned on the outside a round piece of brass hollow'd almost like a concave burning-glass , or one of those tools wherein they use to grind eye-glasses for telescopes . to this piece of brass , which was not considerably thick , nor above inches diameter , was fitted a convex piece of the same metal , almost like a gage for a tool to grind glasses in , which had belonging to it a square handle , whereinto as into a socket was inserted a square piece of wood , proceeding from the basis of a square wooden pillar , which we made use of on this occasion in stead of our vertical cylinder . by the help of another piece of wood coming from the other basis of the same pillar , the turning-key was joyned to this pillar , which was made of such a length , that when the turning-key was forceably kept down as low as the brass cover , it was a part of , would permit ; the convex piece of metal lately describ'd did depress the concave piece a pretty way , notwithstanding a vigorous resistance of the subjacent spring . besides these things , a litle fine powder of emery was put between the convex and concave pieces of brass , to make them more congruous , and facilitate the motion that was to be made ; and there was fastned to the upper part of the turning key a good wimble , without which we presum'd the turning of the key would not produce a sufficient motion : in order to the making of which , it was , after the first tryal , judged requisite to have a strong man , that was us'd to exercise his hands and armes in mechanical labours , upon which account we sent for a certain lock-smith , that was a lusty and dexterous fellow . all things that were thought necessary being thus in readiness , and a mercurial gage being convey'd into the receiver , we caus'd the air to be diligently pump'd out ; and then the smith was order'd to turn the wimble , and to continue to lean a litle on it , that he might be sure to keep the turning-key from being at all lifted up by the formerly mentioned spring . whilst this man with much nimbleness and strength was moving the wimble , i watch'd the gage , to observe whether the agitation of the stop-cock , and consequently the engine , did not prejudice the experiment ; and for greater caution i caus'd the pump to be almost all the while kept at work , though that seem'd not so necessary . when the turner of the wimble was almost out of breath , we let in for hast the air at the cover of the receiver by lifting up the turning-key , and nimbly removing the receiver we felt the pieces of brass , betwixt whom the attrition had been made , and , as we expected , found both of them very sensibly warm . but being willing to confirm the experiment by a second tryal , which we hoped might , after the experience taught us by the first , be somewhat better performed , we caus'd the smith , after he had well refresh'd himself with rest and drink , to lay hold of the wimble again , when the gage made it appear that the receiver was well exhausted , so that by further pumping the quick-silver seem'd not to be further deprest . and in this d tryal the nimble smith plaid his part so well , ( the pump in the mean while not being neglected , ) that when we did as before hastily let in the air , and take out the bodies that had been rubb'd against one another , they were both of them ( especially the uppermost ) so hot , that i could not endure to hold my hand on either of them , and they did for a considerable time retain a not inconsiderable degree of warmth . the same day i caus'd to be made at the turners two bodies of wood , for size and shape like those of brass we had just before imploy'd ; the upper of these was of hard oak , the other of beech , ( such a difference between woods , to be heated by mutual attrition , being thought to be an advantageous circumstance ; ) but though the wimble was swiftly turn'd as before , and that by the same person , nevertheless the wood seem'd not to me ( for all the by-standers were not of my opinion ) to have manifestly acquired any warmth ; and yet that there had been a considerable attrition , appear'd by the great polish which part of the wood had evidently acquir'd , vvhich made me suspect , that though the wood seem'd dry enough , yet it might not really be so , notwithstanding the contrary was affirm'd to me : but not being willing to sit down with a single tryal , i caus'd the experiment to be repeated with more obstinacy than before , the effect of which was , that the wood , especially the upper piece of it , vvas brought to a warmth unquestionably sensible . experiment xlvi . about the slaking of quick-lime in the exhausted receiver . the several scopes i aim'd at in making the following tryal are not necessary to be here particularly taken notice of . but one of them may be guess'd at by the subsequence of this experiment to that immediately foregoing , and the phaenomena of it may be mentioned in this epistle upon the account of their being exhibited by our engine . we took in an evaporating glass a convenient quantity of water , and having convey'd it into a receiver , and well drawn out the air , we let down into it by the turning-key a lump of strong lime , about the bigness of a pipin ; and observ'd not that at the first immersion , nor for some while after , there appear'd any considerable number of bubbles , but within about / of an hour , as i guess'd it , the lime began ( the pump having been and being still ply'd from time to time ) to slack with much violence , and with bubbles wonderfully great , that appear'd at each new exuction , so that the inside of the receiver ( though pretty large ) was at length lin'd with lime-water , and a great part of the mixture did from time to time overflow the vessel , that had purposely been but little fill'd ; nor did any thing but our weariness put a period to the bubling of the mixture , whose heat was sensible even on the outside of the receiver , and which continued considerably hot in the evaporating glass for ¼ of an hour ( as i conjectured ) after the receiver was removed . note , that the lime imployed about this experiment was of a very good and strong kind ( made of hard stones , ) and not such lime , made of chalk , as is commonly used at london , which probably would not have been strong enough to have afforded us the same phaenomenon . experiment xlvii . about an attempt made to measure the force of the spring of included air , and examine a conjecture about the difference of its strength in unequally broad mouth'd vessels . though several of the foregoing tryals have sufficiently manifested that the spring of the air in its natural or wonted state , hath a force very considerable , and indeed much greater than men seem to have hitherto believed ; yet i could not hope by any of these experiments to determine by any known weight , how great that force is , so as to conclude that it is equivalent to such a weight , as so many pounds , ounces , &c. and to no more . wherefore among the uses i had design'd to make of our syringe , formerly often mentioned , it was one , to try if by the help of that instrument , we could determine somewhat near ( for no more was to be expected ) how much weight a cylinder of uncomprest air included in it , and consequently of the same diameter vvith the cavity of the barrel , would be able to sustain or also to lift up . in order to this tryal , . we provided a stable pedestal , or frame , wherein the syringe might be kept firm , and erected . next , vve also provided a weight of lead shap'd like our brass-hoop , or ring , * formerly describ'd , that by the advantage of its figure it might be made to hang down by strings from the top of the handle of the rammer , and so press evenly enough on all sides , without making the upper part of the instrument top-heavy . . we took care to leave , between the bottom of the syringe ( which was firmly clos'd with strong cement ) and that part of it where the sucker was , a convenient quantity of air , to expand its self , and lift up the weight , when the air external to that included air should be pump'd out of the receiver : and lastly , the handle of the rammer ( from which the annular weight lately spoken of depended ) was so fastned to the turning-key of the cover of the receiver , that the weight might not compress the air included in the syringe , but leave it in its natural state or wonted laxity , till the air were withdrawn from the receiver . but notwithstanding all this , when we actually tryed the experiment , that hapned which i feared . for though by this method the included air would well enough lift up a weight of or pound , yet when the rammer came to be clogg'd with so considerable a weight , as my scope in making the experiment required , the instrument prov'd not so stanch , but that it was easier for some particles of air to force themselves a passage , and get away between the sucker and the inside of the barrel , than to heave up so great a weight . and yet i have thought fit to relate the experiment thus particularly , because , if an exact syringe can be procured , ( which i fear will be very difficult , but do not think impossible , this seems to be one of the likeliest and least exceptionable wayes i know , of measuring the force of the airs spring . but despairing to get such a syringe , as i desir'd , in the place where i then was , i bethought my self of another way , by which i hop'd to be able ( though not to arrive at an exact knowledge of the full force of the airs spring , yet ) at least to approach nearer it than i have been able to do by the help of the syringe . for this purpose considering with my self , that if a convenient quantity of air were included in a fine small bladder , the sides of it would hinder the air from getting away , and the limberness of them would permit the air to accommodate it self and the bladder to the figure of a cylindrical vessel , into which it might be put . wherefore with much adoe i procured to be made by a person exercised in turning a couple of hollow cylinders , whose sides were of a sufficient thickness , ( that they might resist the pressure of the air to be imprisoned in them , ) and of such differing breadths , that the first had but one inch in diameter , and the d two ; their depths being also unequal , that the one might receive a much larger bladder than the other . with the lesser of these ( which was very carefully turned ) i made a diligent tryal ; whose circumstances i cannot now acquaint your lordship with , the paper , wherein they vvere amply recorded , having been vvith other notes belonging to this continuation unluckily lost : but the most considerable things in the event were , that t was very difficult to procure a bladder small and fine enough for that litle cylinder ; and that one , which at length we procured , would not continue stanch for many tryals , but would after a vvhile part with a litle air in the well exhausted receiver , when t was clog'd with the utmost weight it could sustain : but whilst it continued stanch vve made one fair tryal vvith it , from vvhence vve concluded , that a cylinder of air of but an inch in diameter , and lesse than two inches in length , was able to raise visibly ( though but a litle ) a weight of above ten pounds , ( i speak of averdupoiz vveights , vvhere a pound contains ounces . ) the manner of making this experiment , and the cautions us'd in judging of it , your lorship may learn by the recital of the subsequent tryal ; my notes about which were not so unfortunate as those that concern'd the former . into a hollow cylinder of wood of four inches in depth , and two in diameter , furnished with a broad and solid bottom or pedestal , to make it stand the firmer , was put a lambs or sheeps bladder very strongly tyed at the neck , on vvhich vvas put a wooden plug , markt with ink where the edg of the cylinder vvas contiguous to it ; this plug being loaded with weights , amounting to pound , ( the uppermost of vvhich weights was fastned to the turning-key , to keep it upright , and to help to raise it at first , ) the receiver vvas exhausted , till the mark appeared very manifestly above the brim of the cylinder ; and then , though the string were by turning the key quite slackned , yet the mark on the plug continued very visible : and vvhen so much air was let into the receiver , as made the weight depress the plug quite beneath the mark , upon the repumping out of the air the weight was without the help of any turning-key lifted up , and by degrees all the mark on the plug was raised about / above the edge of the cylinder . wherefore we substituted for a pound weight one that was estimated at , ( for then we had not a ballance strong enough to weigh it with , ) and using the same bladder we repeated the experiment , onely having a care to support a litle the uppermost weight by the turning-key , till the bladder had attained its expansion ; and then the weight being gently let go , depress'd not the plug so low , but that we could yet see the mark on it , ( which yet was all we could do , ) though that part of the plug , where the mark vvas , vvere manifestly more deprest than the other . for the clearing up of some particulars relating to this tryal , we will subjoyn the following notes . . the plug is to be so fitted to the cavity of the cylinder , as easily to slip up and down in it , without grating against the sides of it , lest it needlesly increase the resistance of the weight to be rais'd . and this plug ought to be of a convenient length , as about an inch and / at least , that it may be the fitter to help to reduce the bladder by compression into a somewhat cylindrical shape , and yet that it may not be thrust in too deep by the incumbent weight ; and that the weight might rest more firmly upon it , there was a broad and strong ledge made at the top of it , by which it might lean on every side upon the brim of the hollow cylinder . . before the instrument was conveyed into the receiver , the bladder ( which ought to be of a just size , and not full blown , and of a fine and limber contexture ) was put into the cylinder , and by divers gradual ( but not immoderate ) compressions was reduc'd to conform its self , as much as might be , to the cylindrical shape of the containing vessel . and then the weight being put on , and taken off again , there was a mark ( in the form of an horizontally plac'd arch ) made with ink , where the edge of the brim of the hollow cylinder did almost touch the plug . this we thought necessary to do , to avoid a mistake ; for we must not judg , that all the weight , that might be rais'd by our bladder , may pass for the weight sought after by our experiment ; since the air in the bladder is by reason of the incumbent weight more comprest than t was before , and consequently its being able to heave up a great weight will not infer , that our common air is able in its natural state ( as they call it ) to exert so great a strength ; that weight being onely to be lookt on as rais'd or sustain'd by the uncomprest air , that is rais'd or sustain'd when the plug is lifted up to the mark , since till then the spring of the air does but bring it back from its new state of adventitious compression to its natural or wonted laxity . . when , after the operation was ended , we took the bladder out of the vessel , it had obtain'd a form cylindrical enough , and though it could be but inches in diameter , yet it was so litle as to be but half an inch more long than broad . . the reason why i chose to have the two cylinders made of the unequal diameters above mentioned , was to examine , as far as by this way i could , a conjecture i had , that the force of the spring of differing cylinders of air to lift up solid weights , would , at the very first raising of the weights , be in duplicate proportion to the diameters of their cylinders , ( those diameters being proportionable to the areas of the plain superficies , against which the air does immediately press , ) without very much considering the inequality that may be between the quantity of the several parcels of air , whose pressures are compared . but t is to be remembred , that i said at the very first raising of the weights , because presently after that , the quantity of the parcels of air may be very considerable : for , as i have shewn in another treatise , two very unequal quantities of air being made by their expansion to possess two equal spaces , the lesser quantity of air must be much more rarified in proportion than the greater ; and consequently , ( to bring this home to our present argument ) though both be lifted up ¼ or ½ of an inch , the spring of a very litle air must be much more weakned than that of a very considerable quantity , and so it cannot continue to lift up its weight , as the above mentioned proportion would ( if it were not for this advertisement ) seem to require . taking then our conjecture in the sense now declared , the success of our tryals is agreeable to it , inviting us to conclude , that the air in the bladder , which was but two inches in diameter , was able by its pressure to countervaile the weight of pound , which is about four times the weight that we lately observ'd the spring of a cylinder of air of one inch in diameter to be able to lift up . for though , according to what we have formerly said of a duplicate proportion , pound seems to be somewhat more than ought to have been lifted up in the cylinder of two inches bore , when that of one inch lifted up not much above pound ; yet this disagrees not with the hypothesis , if we consider that the substance of the bladder straitens the cavity of the smaller cylinder in a greater proportion than that of the bigger . . though we have thus ( as far as the instruments we were able to procure would assist us ) measured the pressure of included air , yet i must not forbear to advertise your lordship , that considering what i formerly observ'd to you about the weight of an atmospherical pillar of an inch in diameter , i cannot but think , that if a cylinder , or other convenient instrument , exactly tite , can be procured , the spring of an aerial cylinder will appear to be greater than we found it by the foregoing tryals ; in which i consider that , not to mention the resistance of the bladder its self , the membraneous substance that lin'd the cylinders ( though t were very thin and fine ) could not but somewhat straiten their cavities , and consequently somewhat ( though not much ) lessen the diameters of the included aerial cylinders . . to all these notes i must adde this advertisement , that it may be therefore the more difficult in such tryals as ours to ascertain the force of the airs spring , because , that air its self when t is included , being shut up with the pressure of the atmosphere upon it , t is probable , that since that pressure ( as we have shewn ) is not at all times the same , the spring of the included air will accordingly be varied . and , if my memory fail me not , when the lately recited experiments were made , our barometer declared the atmosphere to be somewhat light . from what has been hitherto delivered , this may result ; that t is likely , that the spring of an aerial cylinder an inch broad , may be able to sustain , if not raise , a pretty deal more than ten pound weight ; and that the past tryals , without determining that the air can raise no more than in them it did , do , at least , prove that it can raise up as much weight as we have related , since we actually found it to do so . experiment xlviii . about an easie way of making a small quantity of included air raise in the exhausted receiver or pound , or a greater weight . i would very willingly have further prosecuted the foregoing tryals , to see how far the lately propos'd conjecture or hypothesis would hold ; but was hindered by the want of receivers tall and capacious enough to contain the weights , that such an attempt required : but remembring that there were not any experiments made in our engine , that appear'd more strange to the generality of spectators , and serv'd more to give them a high opinion of the airs spring , than those wherein they saw solid bodies actually lifted up by it , and remembring , that i had lying by me a brass vessel , ( which had been bespoken for another experiment , for which the workmen had not made it fit , ) i thought it not amiss to imploy it about making a tryal very easie , and yet fit to be shewn to strangers , to convince them , that the spring of the air is a much more considerable thing than they imagined . we took then a brass vessel made like a cylinder , and having one of his orifices exactly covered with a flat plate very firmly fastned to it , the other orifice being wide open . the depth of this vessel was inches , and the diameter should have been precisely ( but wanted about a quarter of an inch of ) inches . to this hollow cylinder we fitted a wooden plug , like one of those described in the foregoing experiment , save that it was not quite so long , and that it was furnished with a rimme or lip , which was purposely made of a considerable breadth , that it might afford a stable basis to the weight that should lean upon it . and then taking a middle siz'd and limber bladder , strongly tyed at the neck , but not near full blown , we press'd it by the help of the plug into the cylinder to make it the better accommodate it self to the figure of it . then taking notice by an inky mark how much of the plug was extant above the orifice of the vessel , we laid the weights upon the plug , ( whose rimme or lip hinder'd it from being deprest too deep into the cavity of the vessel ; ) and having convey'd them into the receiver , we found as we expected , that if we had loaded the plug but with a single weight , ( as to avoid trouble , and the danger of breaking the glass we usually thought fit to do , ) though that were a common half hundred weight , ( which you know amounts to pounds , ) it would very quickly be manifestly heav'd up by the spring of the included air. for confirmation of more than which , i shall subjoyn the ensuing tryal , as i find it recorded among my loose notes . the weight that was lifted up by the bladder in the cylinder inches broad , was pound ; this weight was lifted up till the wooden plug disclos'd the mark , that was to shew the height , at which the air kept the said plug before it was comprest : disclos'd it i say visibly at the th exuction , and at the th that mark was ⅛ , or rather / above the edge of the cylinder . in the gage where the mercury in the open air was wont to stand about ⅛ above the uppermost glass-mark , it was deprest till it was ⅛ below the second mark . when the air was let in , it was a pretty while before the weight did manifestly begin to subside ; the bladder being taken out , and the place it had possess'd in the cylinder being supply'd with a sleeve , or some such thing , and the weight laid again upon the plug , we found that at exuctions the mercury was deprest to the lowest mark of the gage ; and it was the or th exuction before the receiver appear'd to be so exhausted , as to put an end to the sinking of the mercury , which was then above ⅛ beneath the lowest mark . your lordship will easily believe , that most of the spectators of such tryals thought it somewhat strange to see a small quantity of air , which was not onely uncomprest in the bladder , but did not near fill it , ( and left it very soft and yielding to the least touch , ) lift up so easily by its bare spring such great weights as indeavoured to oppress it . but this not being any thing near a sufficient tryal , how far the conjecture or hypothesis formerly propos'd will hold , i thought fit to make the utmost tryals the tallest receivers i could procure would admit : and having caus'd leaden weights to be purposely cast flat like cheeses , and as broad as we could conveniently put into the receiver , that by the advantage of this shape we might be able to pile up the more of them , without much danger that any of them should be shaken down ; we laid divers of them one upon another , and then the upper part of the receiver growing too narrow to admit more of them , we added a less broad weight or two ; and then exhausting the receiver , till we perceiv'd by the gage that the air was manifestly withdrawn , we found ( as near as we could measure ) by the help of a mark and a pair of compasses , that the plug was so far rais'd , as that t was concluded , that the elevation vvould have been much greater , if the included air , being put upon so great a conatus , had not found it easier to produce some leak at the neck of the bladder , than to lift up so great a weight , which by our reckoning came to about pound of ounces to the pound . but this last experiment , for want of some requisite accommodations , vve vvere hinder'd from repeating and promoting ; though the above mentioned hypothesis made me presume , that a far greater weight might this way have been rais'd if the bladder had been stanch , and the receiver high enough . i need not tell your lordship , that if a larger bladder be imploy'd and included in a brass vessel of a sufficiently wide orifice , a far greater weight may be lifted up by the spring of the internal air. but yet it will not be amiss to give your lordship on this occasion this advertisement , which may be fit to be taken notice of on divers others : that care must be had not to make receivers , that ought to be well emptied , too large , and especially too wide at the orifice ; for otherwayes they will be expos'd to so great a pressure of the atmosphere , that they need be of an extraordinary strength to resist it ; and even receivers , that seem'd thick enough proportionably to their bulk , and which held out very well till the close of the operation , yet when they came to be very diligently exhausted , they did , by reason of the wideness of their orifices , begin to crack at the bottom . experiment xlix . in one of my publish'd experiments * i long since told your lordship , that when i endeavoured , by the help of a seal'd bubble , weigh'd in an exhausted receiver , to compare the gravity of air and water , i was hinder'd by the casual breaking of the glass from compleating the experiment . wherefore i afterwards thought fit to repeat the tryal ; and though when i had done so twice or thrice , having given away the large receiver i had made use of about them , and not being able ever since to procure a good one , that was capacious enough for the tender scales i thought so nice an experiment required , i did not prosecute that attempt so far as i intended ; yet this very difficulty i met with to procure the requisites of making the tryal , invites me to subjoyn the two following notes , which i find among my loose papers . we weigh'd a bubble in the receiver , which we found to weigh above half a grain heavier , when much of the air was exhausted , than when it was full . afterwards we took out this seal'd bubble , and weighing it found it to weigh grains and a half ; then breaking off the small tip of it under water , we found that the heat , by which it was seal'd up , had rarifi'd its included air , so that it admitted grains of water , for the admitted water and glass weighed ½ grains . then filling it full with water , we found it to contain in all grains of water , for it weighed / grains : whence t is evident , that the difference between the weight of water and air was less than to . ] we weighed in the receiver a bubble , the glass of which weighed grains : the air that fill'd it weighed in vacuo / of a grain : the water that fill'd it weighed ¼ grains : so that by this experiment the proportion of the weight of air to water is as ( one ) to ( / . ) the tryals mentioned in these notes , though they were too few for me to acquiesce in , yet being made in a nevv vvay , and which has some advantages above those that have been hitherto imployed to weigh the air , may yet serve to keep us from the contrary . extremes , that have not been avoided by such eminent mathematicians as galileo and ricciolus ; the former of which makes water to be but about times as heavy the air ; and the later , whose conjecture is much remoter from the truth , times heavier . but it is so desireable a thing , and may prove of such importance , to know the proportion in weight betwixt air and water , that i shall not scruple to acquaint your lordship with an attempt or two that i made to discover it by another way : for , though at first sight this experiment may seem to be the same with one publish'd a pretty while ago in the learned schottus his mechanica hydraulico pneumatica ; yet your lordship will easily perceive this difference between them : that , whereas the industrious author of that experiment contents himself to shew , by the diminution of the weight of a glass , when the air has been drawn out of it , that the air , before t was drawn out , was not devoid of gravity ; the following tryal does not onely perform the same thing , and by a superadded circumstance confirm the truth to be thereby prov'd , but it indeavours also to shew the proportion in gravity betwixt the air and water . the tryals themselves were registred among my adversaria as follows . a small receiver being exhausted of air by the engine , and counterpois'd whilst it continued so ; the stop-cock was turn'd , and the air readmitted , which made it weigh grains more than it did before : and to prevent jealousies , we caus'd it to be applied the second time to the engine , by which the air being emptied once more , the glass was put into the other scale of the former ballance , and so counterpois'd ; and then the external air being readmitted , ( which rush'd in as formerly with a whistling noise ) , there was found grains or better , requisite to restore the ballance to an aequilibrium . we took a small glass receiver fitted with a stopcock , and having exhausted it of the air , and counterpois'd it , and let in the outward air , we found the vveight of the vessel to be increased by that admission grains . this done , we took the receiver , after having well counterpois'd it , out of the scale ; and having apply'd it the second time to the engine , we once more withdrew the air , and then turning the stop-cock to keep out the external air , vve took care that none of the cement , imploy'd to joyn it to the engine , should stick to it , as we had diligently freed it from adherent cement before we last apply'd it to the engine . then weighing it again , we found it to weigh either or grains ( but rather the former ) heavier than it did , when t was last counterpois'd in the same ballance . this being also done , we immers'd the stop-cock into a bason of fair water , and let in the liquor , that we might find how much water would succeed in place of the air vve had drawn out . when no more vvater vvas impell'd in , vve turned the stop-cock once more , to keep it from falling out , and then weighing it in the same scales , ( after we had wip'd the stop-cock , that no water might stick to it on the outside , ) we found the water ( without computing the vessel ) to weigh ounces , drachms , and grains , vvhich divided by grains , ( which i took to be the weight of the air , that vvas equal in bulk to this vvater that succeeded it , ) the quotient was ( wanting a very litle ) grains , for the proportion of the vveight between air and water of the same bigness , at the time when the experiment was made : vvhich circumstance i therefore take notice of , because the atmosphere appear'd by the baroscope ( wherein the mercury stood then at inches and / ) to be very heavy ; which made me the less wonder to find this proportion not so great , as at other times i had observed it to be between water and air in point of weight : though i suspected , that because this odd experiment cannot be nimbly dispatched , some litle air may have got in at the stop-cock , besides the air that disclos'd it self in numerous bubbles in the vvater that vvas admitted , vvhere though it lay in such small particles as not to be discerned before ; yet these particles , by this opportunity to expand themselves , extricated themselves from the vvater , and by getting together might somewhat resist the ingress of more ; vvhich is a difficulty , vvhere to the measuring the proportion between vvater and air in a heated eoliple is liable . but the stealing in of any air , before the vvater vvas let in , is mentioned but as a suspicion . your lordship may perhaps think it somewhat strange , that i should present you tryals , whose events do not so vvell agree together , as perchance you expected . but this very disagreement vvas one of the motives that induc'd me to acquaint you vvith them : for all those compris'd in these experiments being made faithfully , and not without ( at the least ) an ordinary diligence , as they seem to make it probable , that one may without any great errour estimate the proportion of our english air to vvater to be as ( one ) to some number betwixt and ; so t is not to be expected , that the proportion , vvhatever it be that should be pitch'd upon , should be accurate and stable . for though learned men seem to have hitherto taken it for granted , that it may suffice once for all diligently to investigate the proportion betwixt those two bodies , yet , not onely i am apt to believe that a determinate quantity of air ( as a pint or quart ) may be unequally heavy in distant countreys , and even in differing places of the same countrey ; but what i have taken notice of in the th of the printed experiments , and afterwards frequently observ'd of the great inequalities of the vveight of the atmosphere , inclines me to think , that in the self same place two experiments may be made with the same instruments , and equal diligence , and yet the weights of the air may be found differing enough ; which may keep your lordship from much wondering , that in the th printed experiment , made when i had the variations of the atmospheres gravity in my eye , i found the air to be less ponderous in reference to water , than in these later tryals . but of this i hope i shall , if god permit , make further tryals with the same vessels , at times when i shall perceive by the baroscope , that the gravity of the atmosphere is very great and very small . and i wish the curious would make the like tryals in other regions . i do not forget , that not onely the school philosophers , but most of the moderns deny , that air hath any weight in air , no more than water in water ; but having a elsewhere declared and explained my sense about this received opinion , i shall not here spend any of the litle time i have remaining , to justifie my dissent ; for which your lordship may find sufficient grounds in the newly related experiments , especially if you please to consider , that though the opinion i disallow have been chiefly and generally grounded upon some arguments supposed to evince , that vvater has no vveight in vvater , i have b elsewhere shewn those proofs not to be cogent , and taught a practical way of weighting vvater in vvater with a pair of ordinary scales . c experiment l. about the disjoyning of two marbles ( not otherwise to be pull'd asunder without a great weight ) by withdrawing the pressure of the air from them . in our formerly publish'd experiments about the air * , i did , if i misremember not , acquaint your lordship with an attempt i had made to make a couple of coherent marbles fall asunder , by withdrawing the air from them ; but though i then esteem'd that their cohaesion depended upon the pressure of the air , yet not being at that time furnish'd with all the accommodations requisite to make an experiment not easie to be perform'd succeed , i thought fit , when i had afterwards opportunity , to prosecute what i then began , and add some circumstances that i could not then make tryal of ; and yet whose success will not i presume be unwelcome , since it supplies us with no less than matters of fact ; whence we may argue , that this experiment of coherent marbles ( which not onely the aristotelian plenists have of late much triumph'd in , but which some recent favourers of our hypothesis have declar'd themselves to be troubled with ) is not onely reconcileable to our doctrine , but capable of being made a confirmation of it ; notwithstanding what has lately been publish'd ( upon the supposition of a case , which at first blush may seem somewhat of kin to our experiment , ) by a very learned * writer , to whose objection against our hypothesis , though as well confidently as very civilly proposed , an answer may in due place , if your lordship desire it , be return'd . we took two flat round marbles , each of them of two inches and about quarters in diameter , and having put a litle oyl between them to keep out the air , we hung at a hook fastned to the lowermost a pound weight to surmount the cohaesion , which the tenacity of the oyl and the imperfect exhaustion of the receiver might give them . then having suspended them in the cavity of a receiver , at a stick that lay ( horizontally ) a cross it ; when the engine was fill'd , and ready to work , we shook it so strongly , that those that were wont to manage it , concluded , it would not be near so much shaken by the operation . then beginning to pump out the air , we observ'd the marbles to continue joyned till it was so far drawn out , that we began to be diffident whether they would separate . but at the th suck , upon the turning of the stop-cock , ( which gave the air a passage out of the receiver into the pump , ) the shaking of the engine being almost , if not quite , over , the marbles spontaneously fell asunder , wanting that pressure of the air , that formerly had kept them together : which event was the more considerable , not onely because they hung parallel to the horizon , but adher'd so firmly together when they were put in , that having try'd to pull them asunder , and thereby observ'd how close they stuck together , i foretold it would cost a good deal of pains so far to withdraw the air , as to make them separate : which conjecture your lordship will the less wonder at , if i adde , that a weight of and odd pounds , fastned to the lowermost marble , may be drawn up together with the uppermost , by vertue of the firmness of their cohesion . nb. this is not the onely time that this experiment succeeded with us . for sometimes , when they were not so closely press'd together before they were put in , the disjunction was made at the th suck , or sooner , and we seem'd to our selves to observe , that when we hung but half a pound weight to the lower marble , it requir'd a greater exhaustion of the receiver to separate them , than when we hung the whole pound . after , having proceeded thus far with the instruments we then had , meeting with an artificer that was not altogether unskilful , we directed him to make ( what we wanted before in that place ) such a brass-plate to serve for a cover or cap to the upper orifice of receivers open at the top , as we have divers times had occasion to mention already in giving accounts of some of the foregoing tryals : by the help of which contrivance we prosecuted the newly related experiment much further than we could do before , as may appear by the following account . we fasten'd to the lower most of the two marbles a weight of a very few ounces , ( for i remember not the precise number , ) and having cemented the capp'd receiver with the marbles in it , as before , to the pump , we did by a string , whereof one end was tied to the bottom of this turning-key , and the other to the uppermost marble , and which ( string ) past through the crank or hook belonging to the brass-cover ; we did , i say , by the help of this string , and by turning round the key , draw up the superiour marble , and by reason of their coherence the lowermost also , together with the weight that hung at it : by which means being sure , that the two marbles stuck close together , we began to pump out the air that kept them coherent ; and after a while , the air being pretty well withdrawn , the marbles fell asunder . but we having so order'd the matter , that the lowermost could fall but a litle way beneath the other , we were able by inclining and shaking the engine to place them one upon another again , and then letting in the air somewhat hastily , that by its spring it might press them hard together , we found the expedient to succeed so well , that we were not onely able by turning the abovementioned cylindrical key , to make the uppermost marble take up the other , and the annexed weight ; but we were fain to make a much more laborious and diligent exhaustion of the air to procure the disjunction of the marbles this second time , than was necessary to do it at the first . and for further prevention of the objections or scruples that i foresaw some prepossessions might suggest , i thought fit to make this further tryal , that when the marbles were thus asunder , and the receiver exhausted , we did , before we let in the air , make the marbles fall upon one another as before ; but the litle and highly expanded air that remained in the receiver , having not a spring near strong enough to press them together , by turning the key we very easily rais'd the uppermost marble alone , without finding it to stick to the other as before . whereupon we once more joyn'd the marbles together , and then letting in the external air , we found them afterwards to stick so close , that i could not without inconvenience strain any further , than i fruitlesly did , to pull them fairly asunder ; and therefore gave them to one that was stronger than i , to try , whether he could do it , which he also in vain attempted to perform . and now , my lord , though i had thoughts of adding divers other experiments to those i have hitherto entertained you with ; yet ( upon a review ) finding these to amount already to fifty , i think it not amiss to make a pause at so convenient a number . and the rather , because an odd quartainary distemper , that i slighted so long , as to give it time to take root , is now grown so troublesome , that i fear it may have too much influence upon my style ; which apprehension obliges me as well to avoid abusing , or distressing your lordship's patience , as to allow my self some seasonable refreshment , to reserve the mention of the design'd additions till they can with less trouble to us both be presented you by my dear lord your lordship's most humble servant , and affectionate uncle , robert boyle . oxford , march the . . notes &c. about the atmospheres of consistent bodies ( here below . ) shewing , that even hard and solid bodies ( and some such as one would scarce suspect ) are capable of emitting effluvia , and so of having atmospheres . an advertisement . he that shall take the pains to peruse the following paper , will easily believe me , when i tell him , that t was not design'd to come abroad with the experiments , in whose company it now appears . but the stationer earnestly representing that divers experiments being reserved by me for another occasion , the remaining ones alone would not give the book a thickness any thing proportionable to its breadth ; i consented , at his sollicitation , to annexe to them the following observations , because of some affinity between the small atmospheres of lesser bodies , and the great atmosphere that surrounds the terrestrial globe ; in which the other , that do at least help to compose it , are lost and confounded , as brooks and rivers are in the ocean . and to save the reader the pains of making guesses to what kind of writing the ensuing discourse may belong , i shall here intimate , that t is dismembred from certain papers about occult qualities in general , which make part of the notes i long since designed , and also partly published , about the origine of qualities , of which notes those that concern'd effluviums , being the most copious , i referr'd them to four general heads ; whereof the first onely is treated of in the following discourse , the others being withheld , as having not affinity enough with the atmosphere to accompany this , whereon they have no such absolute dependance , but that they may well enough spare it . and i make the less scruple to let it appear without them , because the inducements already mentioned are not a litle strengthned by this superadded consideration , that the following notes may give light to several of the observations i have made of some lesse heeded phanomena of the alterations of the air , in case they be allowed to enter into the appendix to this continuation . of the atmospheres of consistent bodies . the school philosophers , and the vulgar , in considering the more abstruse operations and phaenomena of nature , are wont to run into extremes ; which , though opposite to one another , do almost equally contribute to keep men ignorant of the true causes of those effects they admire . for the vulgar , being accustomed to converse with sensible objects , and to conceive grosly of things , cannot easily imagine any other agents in nature , then those that they can see , if not also touch , and handle ; and as soon as they meet with an effect , that they cannot ascribe to some palpable , or at least sensible efficient , they are , and stick not to confess themselves utterly at a loss . and though the vulgar of philosophers will not acknowledg themselves to be pos'd by the same phaenomena with the vulgar of men , yet in effect they are so . but the school-philosophers on the contrary , do not onely refuse to acquiesce in sensible agents , but to solve the more mysterious phaenomena of nature , nay and most of the familiar ones too , they scruple not to run too far to the other side , and have their recourse to agents that are not onely invisible , but inconceivable , at least to men that cannot admit any save rational and consistent nations : they ascribe all abstruse effects to certain substantial forms , which however they call material , because of their dependence on matter , they give such descriptions to , as belong but to spiritual beings : as if all the abstruser effects of nature , if they be not perform'd by visible bodies , must be so by immaterial substances : whereas betwixt visible bodies and spiritual beings there is a middle sort of agents , invisible corpuscles ; by which a great part of the difficulter phaenomena of nature are produc'd , and by which may intelligibly be explicated those phaenomena , which 't were absurd to refer to the former , and precarious to attribute to the latter . now for methods sake i will refer the notes , that occur to me about effluviums , to four heads ; whereof the first is mentioned in the title of this paper , and each of the other three shall be successively treated of in as many distinct ones . that fluid bodies , as liquors , and such as are manifestly either moist , or soft , should easily send forth emanations , will i presume be granted without much difficulty ; especially considering the sensible evaporation that is obvious to be observ'd in water , wine , urine , &c. and the loose contexture of parts that is suppos'd to be requisite to constitute soft bodies , ( as flowers , balsomes , and the like : ) but that even hard and ponderous bodies , notwithstanding the solidity and strict cohesion of their component parts , should likewise emit steams , will to many appear improbable enough to need to be solemnly prov'd . whether you admit the atomical hypothesis , or prefer the cartesian , i think it may be probably deduc'd from either , that very many of the bodies we are treating of , may be suppos'd exhaleable as to their very minute parts . for according to the doctrine of lucippus , democritus , and epicurus , each indivisible particle of matter hath essentially either a constant actual motion , or an unlooseable endeavour after it , so that though it may be so complicated in some concretions , with other minute parts , as to have its avolation hindred for a while ; yet it can scarce otherwise be , but by this incessant indeavour of all the atomes to get loose , some of them should from time to time be able to extricate themselves , and fly away . and though the cartesians do not allow matter to have any innate motion , yet according to them both vegetables , animals , and minerals , consist of litle parts so contexed , that their pores give passage to a celestial matter ; so that this matter continually streaming through them , may well be presum'd to shake the corpuscles that compose them : by which continued concussion now some particles , and then others , will be thrown and carried off into the air , or other contiguous body , fitted to receive them . but though by these , and perhaps other considerations , i might indeavour to shew à priori , as they speak , that t is probable consistent bodies themselves are exhaleable , yet i think it may be as satisfactory , and more useful , to prove it à posteriori , by particular experiments , and other examples . that then a dry and consistent form does not necessarily infer , in the bodies that are endowed with it , an indisposition to send forth steams , which are as it were litle colonies of particles , is evident , not onely in the leaves of damask roses , whether fresh or dried ; as also in wormwood , mint , rue , &c : but in ambergreece , musk , storax , cinamon , nutmegs , and other odoriferous and spicy bodies . but more eminent examples to our present purpose may be afforded us by camphire , and volatile salts , such as are chymically obtain'd from harts-horn , blood , &c. for these are so fugitive , that sometimes i have had a considerable lump of volatile salt ( either of fermented urine , or of harts-horn ) fly away by litle and litle out of a glass , that had been carefully stopt with a cork , without leaving so much as a grain of salt behind it . and as for camphire , though by its being uneasie to be powder'd , it seems to have something of toughness or tenacity in it ; yet i remember , that having for tryals sake counterpois'd it in nice scales , even a small lump of it would in a few hours suffer a visible loss of its weight , by the avolation of strongly sented corpuscles , and this , though the experiment were made both in a north window , and in winter . but i expect you should require instances of the effluviums of bodies of a close or solid texture ; wherefore i proceed to take notice , that amber , hard wax , and many other electrical bodies do , when they are rubb'd , emit effluviums . for though i will not now meddle with the several opinions about the cause and manner of electrical attraction , yet besides that almost all the modern naturalists , that aim at explicating things intelligibly , ascribe the attraction we are speaking of to corporeal effluxes ; and besides that i shall ere long have occasion to shew you , that there is no need to admit with cartesius , that because some electrical bodies are very close and fixt , what they emit upon rubbing is not part of their own substance , but somewhat that was harbour'd in their pores : besides these things , i say , i have found that many electrical bodies may by the very nostrils be discovered , when they are well rubb'd , to part with store of corpuscles , as i have particularly , but not without attention , been able to observe in amber , rosin , brimstone , &c. i know not whether it will be worth while to take notice of the great evaporation i have observ'd , even in winter , of fruits , as apples , and of bodies that seem to be better cover'd , as eggs , which notwithstanding the closeness of their shels , did daily grow manifestly lighter and lighter ; as i observ'd in them , and divers other bodies , that i kept long in scales , and noted their decrements of weight : but perhaps you will be pleas'd to hear , that having a mind to shew how considerable an evaporation is made from wood , i caus'd a thin cup , capable of holding about a pint , or more , to be turn'd of a wood , that was chosen by the turner as solid and dry enough , though it were not of the closest sort of woods , such as are lignum vitae , and box. and as i caus'd the shape of a cup to be given it , that it might have a greater superficies expos'd to the air , and consequently might be the fitter to emit store of steams into it ; so the success did not onely answer my expectation , but exceed it : for though the tryal were made some time in winter , there was so quick and plentiful an evaporation made from the cup , that i found it no easie matter to counterpoise it ; for whilst grains were putting into the opposite scale , to bring the tender ballance to an aequilibrium , the copious avolation of invisible steams from the wood ( which had so much of superficies contiguous to the air ) would make the scale that held it sensibly too light . and i remember , that for further satisfaction , being afterwards in a city where there were both good materials and workmen , i order'd to be made a boule , about the same bigness with the former , of well season'd wood , which being suspended in the chamber i lay in , ( which circumstance i therefore mention , because the weather and a litle physick i had taken obliged me to keep a fire there , ) it quickly began manifestly to loose of its weight ; and though the whole cup wanted near two drams of ounces , yet in hours , viz. from a clock in the morning to the same hour at night ; it lost about grains , ( for t was above : ) but of such experiments , and the cautions belonging to them , i may elsewhere speak farther . it were not difficult for me to multiply instances of the continual emanation of streams from vegetable and animal substances ; but i am not willing to enlarge my self upon this subject , because i consider that there are other bodies which seem so much more indispos'd to part with effluviums , that a few instances given in such , may evince what i would prove , much more then a multitude produc'd in other bodies . and since i consider that those substances are the most unlikely to afford effluvia , that are either very cold , or very ponderous , or very solid and hard , or very fixt ; if i can shew you that neither of these qualifications can keep a body from emitting steams , i hope i shall have made it probable , that there is no sort of bodies here below that may not be thought capable of affording the corporeal emanations we speak of . and first i remember , that i have not onely taken eggs , and in a very sharp winter found them , notwithstanding the coldness of the air where i kept them , to grow sensibly lighter , in a faithful pair of scales , in not very many hours ; but because ice is thought the coldest visible body we know , i thought fit to shew that even this body will loose by evaporation ; for having counterpois'd a convenient quantity of ice in a good ballance , and forthwith expos'd it therein to the cold air of a frosty night , that the evaporations should be from ice not from water , i found the next morning , that though the scale wherein the ice were put was dry , which argued as well as the coldness of the weather that the expos'd concretion had not thaw'd ; yet i found its weight to be considerably diminished , and this experiment i succesfully made in more than one winter , and in more than one place . and t is now but a few dayes since , exposing not long before midnight , lesse than two ounces of ice in a good ballance to a sharply freezing air , i sent for it before i was up in the morning , and though by the dryness of the scales the ice that was in one of them appear'd not to have thaw'd , yet it had lost about ten grains of its former weight ; so that here , the evaporation was made in spite of a double cold , of the ice , and of the air. i should now proceed to the mention of ponderous and solid bodies , but before i do so , it may be expedient to give you notice , that , to make the proof of what i have propos'd more satisfactory , and more applicable to our future purposes , i shall forbear to give you any examples of the exhalations of bodies , where so potent an agent as the fire is made to intervene . but though i purposely forbear to insist on such examples , yet it may not be amiss to intimate , that in explicating some occult qualities , even such exhalations as are produc'd by the help of the fire may be fit to be taken into consideration , as we may hereafter have occasion to shew . and therefore we may observe in general , that the fire is able to put the parts of bodies into so vehement a motion , that except gold , glass , and a very few more , there are not any bodies so fixt and solid , that t is not thought capable to dissipate either totally , or in part . t is known to those that deal in the fusion of metals , that not onely lead and tin , but much harder bodies will emit copious and hurtful steams . and there are some kinds of that iron , which our smiths call cold share iron , about whose smell whilst it was red hot , when i made inquiry , the ingeniousest smith i had then met with told me , that he had found it several times to be so strong , and rank , that he could scarce indure to work with his hammer those parcels of metal whence it proceeded . and even without being brought to fusion , not onely brass , and copper will , being well heated , become strongly sented , but iron will be so too , as is evident by the unpleasing smell of many iron-stowes . and on this occasion i might not impertinently adde here a tryal we made to observe , whether the steams of iron may not be made , though not immediately visible , yet perceptible to the eye it self , though the metal had not a red , much less a white heat . but having elsewhere related it at large , in a discourse you may command a sight of , i shall rather refer you to it , than loose the time 't would take up to transcribe it . these things premis'd , i proceed now to the mention of ponderous bodies ; and concerning them , to represent , that if you will admit what almost all the corpuscularians assert , and divers of the peripateticks do not now think fit to deny , that the magnetical operations are perform'd by particles issuing forth of the body of the loadstone , or other magnetical agent : i shall not need to go far for an instance to our present purpose , since i have hydrostatically found , that some loadstones ( for i have found those minerals very differing in gravity ) are so ponderous , as to exceed double the weight of flints , or other stones of the same bulk . but not to insist on loadstones , stone-cutters will inform you , ( as they did me , ) that black marble , and some other solid and heavy stones will , upon the attrition they are expos'd to , when the workmen are polishing them , ( especially without water , ) emit , and that without the help of external heat , a very sensible smell , which i found to be much more strong and offensive when , to make it so , i had the curiosity to cause a piece of solid black marble to have divers fragments struck off from it with a chizel and a hammer : for the stroaks succeeding one another fast enough to make a great concussion of the parts of the black marble , ( for in white , which is not so solid , the tryal will not succeed well , ) there quickly follow'd as i expected a rank and unpleasant smell ; and you will grant me i know , that odours are not diffus'd without corporeal emanations . i remember also , that having procur'd some of those acuminated and almost conical stones , that pass among the vulgar for thunder-stones , by rubbing them a litle one against the other , i could easily according to my expectation excite a strong sulphureous stink . i have also tried upon a certain mineral mass , that was ponderous almost as a metal , but to me it seem'd rather an unusual kind of marchasite , that i could in a trice without external heat make it emit more strongly sented exhalations , than i could contentedly endure : to which i shall adde this example more , that having once made a chemical mixture of a metalline body , and coagulated mercury , which you will believe could not but be ponderous , though this mixture had already endur'd as violent a fire as was necessary to bring it to fusion , in order to cast it into rings ; yet it was so dispos'd to part with corporeal effluxes , that a very ingenious person that practis'd physick , and was there when i made it , earnestly begg'd a little of it of me for some patients troubled with distempers in the eyes , and other parts remote enough from the hand ; which he affirm'd himself to have very happily cured , by making the patient wear a ring of this odde mixture , or wearing a litle of it as an appensum near the disaffected part . if you make a vitrum saturni with a good quantity of minium in reference to the sand or chrystal , which it helps to bring to fusion , you shall have a glass exceeding ponderous , and yet not devoid of electricity : and i remember , that having sometimes caus'd brass it self to be turn'd like wood , that i might try , whether so great ( though invisible ) a concussion of all the parts would not throw off some steams that might be smell'd , i was not reduc'd to foregoe my expectation ; but yet because it was not fully answer'd , and because also there is great difference of brass upon the score of the lapis calaminaris , whereof together with copper t is made , i enquired of the workman , who us'd to turn great quantities of brass , whether he did not often after find it more strong ; and he inform'd me that he did , the smell being sometimes so strong , as to be offensive to strangers , that came to his shop , and were not us'd to it . i proceed now to the effluviums of solid and hard bodies , of which , if most of our corpuscularian philosophers , and divers others be not much mistaken , i may be allow'd to give instances in all electrical bodies , which , as i have already noted , must according to their doctrine be acknowledged to operate by substantial emanations . now among electrical bodies i have observ'd divers , that are of so close a texture , that aqua fortis its self , nor spirit of salt will work upon them , and to be so hard , that some of them will strike fire like flints : of the former sort i have found divers gems ( which i nam'd in my notes about electricity , ) and even the cornelian it self , which i found to attract hairs , though it be thought to be of a much slighter texture than precious stones , did yet resist aqua fortis , as i tried in a large ring , ( brought out of the east-indies , ) which i purposely broke , and reduced some part of it to powder , that i might make these and some other tryals with it . rock chrystal also , though it have a very manifest attractive virtue ( as they call it , ) i have yet found it so hard , as to strike fire rather better than worse than ordinary flints . and to shew that no hardness of a body is inconsistent with its being electrical , i shall adde , that though diamonds be confest to be the hardest bodies that are yet known in the world , yet frequent experience has assur'd me , that even these , whether raw or polish'd , are very manifestly ( and sometimes vigorously enough ) electrical . and to let you see , that i need not to have recourse to this kind of bodies , to prove , that very solid ones are capable of effluvia ; i will , to what i have formerly noted about the odour of black marble , subjoin two or three examples of the like nature . the first shall be taken from a sort of concretions very well known in divers parts of italy by the name of cugoli , because of the great use that is made of it by the glass-men . these concretions you will easily believe are very hard , as other minerals of that sort are wont to be ; and yet being invited by my conjectures about the atmospheres of bodies , to try them by rubbing them one against the other , i found as i expected , that they afforded not onely a perceptible , but a very strong smell , ( which was far from that of a perfume . ) and this brings into my mind , that having met with some stones cut out of humane bladders , whose texture was so close , that i could not with corrosive menstruums make any sensible solution of one whereon i made my tryal ; though to facilitate the liquors operation , part of it were reduc'd to fine powder , yet by a litle rubbing of one of these so closely contexed stones , it would presently afford a rank smell , very like the stink of stale urine . i remember i have caus'd iron to be turn'd with a lath , to examine whether by the internal commotion , that would by that operation be produc'd in the corpuscles of the metal , even that solid as well as ponderous bodie would not become capable of being smell'd ; and though by reason of the nature of that parcel of iron whereon we made our tryal , or some accidental disposition , which was at that time ( being winter ) in my organs of smelling , the odour seem'd to me but very faint ; yet upon the enquiry i made of the artificers , whether in turning greater pieces of iron they did not find the smell stronger ? they told me , that they often found it very strong , and sometimes more so than they desired . and this brings into my mind , what i have carefully observ'd in grinding of iron ; for there are many grindstones so qualify'd , that in case iron instruments be held upon the stone , whilst it is nimbly turn'd under it , though the water that is wont to be us'd on such occasions stifles ( if i may so speak ) the smell , and keeps it from being commonly taken notice of ; yet if you purposely cause ( as i remember i have done ) the use of water to be forborn , your success will not be like mine , if you do not find that store of foetid exhalations will be produc'd . and though it be not always so easie to discern by the smell , from which of the two bodies they issue , or whether they proceed from both ; yet it seems probable enough , that some of the steams come from the iron , and t is more than probable that if they proceed not from that metal , they must from a body that is so hard as to be able to make impressions in a trice upon iron and steel themselves . the last example i shall name under this head , is furnish'd me by marchasites , some of which would after a short concussion without external heat be made to exhale for a pretty while together a strong sulphureous odour , and yet were so hard , that when struck with a steel-hammer , ( which would not easily break them ) they afforded us such a number of sparks , as appear'd strange enough . and t is known , that t is from their disposition to strike fire , ( which yet i dare not attribute to all sorts of marchasites , ) that this kind of mineral is , by a name frequently to be met with in writers , call'd pyrites . and in this example we may take notice , that a body , capable of being the source of corporeal emanations , may be at once both very solid and very ponderous . it remains now that i manifest , that even the fixedness of bodies is not incompatible with their disposition to emit effluviums . i might alleadg on this occasion , that the regulus of antimony , and also its glass , though they must have endur'd fusion to attain their respective forms ; yet they will without heat communicate to liquors antimonial expirations , with which those liquors being impregnated become emetick and purgative . i might also adde , that divers electrical bodies are very fixt in the fire , and particularly that chrystal , as we have more than once tried , will endure several ignitions and extinctions in water , without being truly calcin'd , being indeed but crackt into a great multitude of litle parts ; but because the above named antimonial bodies will after a while fly away in a strong fire , and because the effluviums of chrystal are not so sensible as those which can immediately affect our eyes or nostrils , i will here subjoyn one instance , such as i hope will make it needless for me to adde any more , it being of a body which must have sustain'd an exceeding vehement fire , and is look'd upon by most of the chymists as more understroyable then gold it self , and that is glass , which is able as you know to endure so great a brunt of the fire , that you did not perhaps imagine i should of all bodies name it on this occasion . but my conjectures about the atmospheres of bodies leading me to think , that glass it self might afford me a confirmation of them ; i quickly found , that by rubbing a very litle while two solid pieces of it ( not , as i remember , of the finer sort ) one against the other , they would not onely yield a sensible odour , but sometimes so strong an one , as to be offensive . by which you will easily perceive why i told you above , that i did not acquiesce in the cartesian argument against electrical bodies performing their operations by emanations of their own substance , drawn from hence , that glass does attract light bodies , ( as indeed it does , though but weakly , ) and yet is too fixt to emit effluviums , the contrary of which supposition the lately mentioned experiment ( and by us often repeated ) does sufficiently evince . from what other solid bodies , and that will endure the fire , i have , or have not been able to obtain such odorous steams , it is not necessary to declare in this place , but may perhaps be done in another . you may i presume have taken notice , that according to what i intimated a while agoe , i have forborn in the precedent examples to mention those effluvia of solid bodies , that need the action of the fire to be obtain'd . but since the sun is the grand agent of nature in the planetary world , and since during the summer , and especially at noon , and in southern climates , his heat makes many bodies have litle atmospheres , that we cannot so well discern that they have constantly ; i see not why i may not be allow'd to ascribe atmospheres to such bodies , as i have observ'd to have them when the sun shines upon them , and also to think that the like may be attributed at least sometimes to such other bodies , as will do the things usually perform'd by effluviums , when yet they are excited but by an external heat , which exceeds not that of the hot sun. of these two sorts of bodies i shall for brevities sake name but two or three examples , and then hasten to a conclusion . the first of these i must make bold to borrow from my observations about electricity , among which this is one , that to shew that the particular and usual manner of exciting such bodies , namely by rubbing them , is not alwayes necessary ; i took a large piece of good amber , and having in a summer morning , whilst the air was yet fresh , tried that it would not without being excited attract a light body i had expos'd to it ; i remov'd it into the suns beams , till they had made it moderately hot , and then i found according to my expectation that it had acquir'd an attractive virtue , & that not onely in one particular place , as is usually observ'd when t is excited by rubbing , but in divers and distant places at once ; at any of which it would draw to it the light body plac'd within a convenient distance from it : so that even in this climate of ours a solid body may quickly acquire an atmosphere by the presence of the sun , and that long before the warmest part of the day . the next instance you will perchance think somewhat strange , it being that when for want of an opportunity to make the like trial in the warm sun , i took a litle but thick vessel made of glass , and held it near the fire till it had got a convenient degree of heat , ( which was not very great , though it exceeded that which i had given the amber , ) i found as i had imagin'd that the heat of fire had made even this body attractive , as that of the sun had made the other . what degree of heat i have observ'd to be either necessary , or the most convenient to excite electrical bodies according to their different natures , ( for the same degree will not indifferently serve for them all , ) this is not the properest place to declare , and it will be more to our present purpose to make some short reflection on what has been hitherto delivered . it seems then probably deduceable from the foregoing experiments and observations , that a very great number if not the greatest part even of consistent bodies , whether animal , vegetable , or mineral , may emit effluviums , and that even those that are solid may ( at least sometimes ) have their litle atmospheres , though the neighbouring solids will often keep the evaporations from being every way ambient in reference to the bodies they issue from . for as the instances hitherto alleadg'd ( which are not all that i could have nam'd ) do plainly shew that divers bodies ( and some that have not been thought very likely ) are such as we speak of , so several things induce me to believe , that there may be many more of the like nature . for first , very few if any have ( that i know of ) had the curiosity to make use of nice scales , ( which such tryals require , ) to examine the expirations of inanimate bodies , which if they shall hereafter do , i make litle doubt but they will light on many things , that will confirm what we have been proposing , by their finding that some bodies , which are not yet known to yield exhalations , do afford them , and that many others do part with far more copious ones than is imagin'd . for one would not easily have thought , that so extremely cold a body as a solid piece of ice should make a plentiful evaporation of its self in the cold air of a freezing night ; or that a piece of wood , that had long lain in the house , and was light enough to be conveniently hung for a long time at a ballance , that would loose its aequilibrium with ( as i remember ) half a quarter of a grain , should in less than a minute of an hour , send forth steams enough to make the scales manifestly turn , and that in winter . but supposing ( which is my second consideration ) that tryals were made with good instruments for weighing , though it will follow , that in case the exposed body grow lighter , something exhales from it ; yet it will not follow , that if no diminution of weight be discover'd by the instrument , nothing that is corporeal recedes from it . i will not urge that t is affirm'd , not onely by the generality of our chymists , but by learned modern physitians , that when either glass of antimony , or crocus metallorum impregnate wine with vomative and purgative particles , they do it without any decrement of their weight ; because the scales in apothecaries shops , and the litle accurateness wont to be imployed in weighing things , by those that are not vers'd in statical affairs , make me ( though not deny the tradition which may perchance be true , yet ) unwilling to build upon observations , which to be relyed on are to be very nicely made ; and therefore i shall rather take notice , that though the loadstone be concluded to have constantly about it a great multitude of magnetical effluvia , ( which may be call'd its atmosphere , ) yet it has not been observed to loose any thing of its weight by the recess of so many corpuscles . but because if the cartesian hypothesis about magnetisms be admitted , the argument drawn from this instance will not be so strong as it seems , and as it otherwise would be : i shall add a more unexceptionable example , for i know you will grant me that odours are not diffus'd to a distance without corporeal emanations from the odorous body : and yet , though good amber-greece be , even without being excited by external heat , constantly surrounded by a large atmosphere , you will in one of the following discourses find cause to admire how inconsiderable the wast of it is . if it be said , that in tract of time a decrement of weight may appear in bodies , that in a few hours or dayes discovers not any ; the objection , if granted , overthrows not our doctrine , it being sufficient to establish what we have been saying , if we have evinc'd that the effluvia of some bodies may be subtle enough not to make the body by their avolation appear lighter in statical trials , that are not extraordinarily ( and as it were obstinately ) protracted . and this very objection puts me in mind to adde , that for ought we know the decrement of bodies in statical experiments long continued , may be somewhat greater than even nice scales discover to us ; for how are we sure that the weights themselves , which are commonly made of brass , ( a metal very unfixt , ) may not in tract of time suffer a litle diminution of their weight , as well as the bodies counterpois'd by them : and no man has i think yet tryed whether glass , and even gold may not in tract of time loose of their weight , which in case they should do , it would not be easily discover'd , unless we had bodies that were perfectly fixt , by comparison to which we might be better assisted , than by comparing them with brass weights , or the like , which being themselves less fixt , will lose more than gold and glass . my third and last consideration is , that there may be divers other wayes , besides those furnish'd us by staticks , of discovering the effluvia of solid bodies , and consequently of shewing , that t is not safe to conclude , that because their operation is not constant or manifest , such bodies do never emit any effluvia at all , and so are uncapable to work by their intervention on any other body , though never so well dispos'd to receive their action . and this i the rather desire that you would take notice of , because my chief ( though not onely ) design in these notes is ( you know ) to illustrate the doctrine of occult qualities ; and it may conduce to explicate several of them , to know that some particular bodies emit effluvia , though perhaps they do it not constantly , and uniformly ; and though perchance too , they do not appear to emit any at all , if they be examin'd after the same manner with other exhaleable bodies , but onely may be made to emit them by some peculiar way of handling them , or appear to have emitted them by some determinate operation on some other single body , or at most small number of bodies . perchance you did not think , till you read what i lately told you about glass , that from a body that had endured so violent a fire , there could , by so sleight a way as rubbing a litle while one piece against another , be obtain'd such steams , as may not onely affect but offend the nostrils . nor should we easily believe , if experience did not assure us of it , that a diamond , that is justly reputed the hardest known body in the world , should by a litle rubbing be made to part with electrical effluvia . nay , ( that i may give some kind of confirmation to that part of the last paragraph that seems most to need it , ) i shall adde , that i once had a diamond not much bigger than a large pen , which had never been polish'd or cut , whose electrical virtue was sometimes so easily excited , that if i did but pass my fingers over it to wipe it , the virtue would disclose it self ; and if as soon as i had taken it out of my pocket , i applied a hair to it , though i touch'd not the stone with my fingers , that i might be sure not to rub it , that hair would be attracted at some distance , and many times one after an other , especially by one of the sides of the stone , ( whose surface was made up of several almost triangular planes , ) and though this excitation of the diamond seemed to proceed onely from the warmth that it had acquir'd in my pocket , yet i did not find that that warmth , though it seem'd not to be alter'd , had alwaies the same effect on it , though the wiping it with my finger fail'd not ( that i remember ) to excite it . something like this uncertainty i always observ'd in another diamond of mine , that was much nobler than the first , and very well polished , and in a small ruby , that i have yet by me , which would sometimes be considerably electrical without being rubb'd , when i but wore the ring it belong'd to on my litle finger ; and sometimes again it seem'd to have lost that virtue ( of operating without being excited by friction , ) and that sometimes within a few minutes , without my knowing whence so quick a change should proceed . but i must insist no longer on such particulars , of which i elsewhere say something ; and therefore i prceed to take notice , that we should scarce have dream'd , that when a partridg , or a hunted deer has casually set a foot upon the ground , that part where the footstep hath been ( though invisibly ) impress'd , should continue for many hours a source of corporeal effluxes ; if there were not setting dogs , and spaniels , and bloud-hounds , whose noses can take notice at that distance of time of such emanations , though not onely other sorts of animals , but other sorts of dogs are unable to do so . i saw a stone in the hands of an academick , an acquaintance of mine , which i should by the eye have judg'd to be an agate , not a blood stone , and consequently i should not have thought that it could have communicated medicinal effluvia appropriated to excessive bleeding , if the wearer of it had not been subject to that disease , and had not often cur'd both himself and others , by wearing this stone about his neck ; which if he left off , as sometimes he did for trials sake , his exceedingly sanguine complexion ( to which i have rarely seen a match ) would in a few daies cast him into relapses . what i have elsewhere told you about the true virtues of some stones , ( for i fear that most of those that are wont to be ascrib'd to them are false , ) may give some confirmation to what i have been delivering , which i cannot now stay to do , being to draw to a conclusion as soon as i have put you in mind , that it would not probably have ever been expected that so ponderous and solid a body as the loadstone should be invironed by an atmosphere , if iron had been a scarce mineral , and had not chanc'd to have been plac'd near it . and with this instance i shall put an end to these notes , because it allows me to make this reflextion ; that since solid bodies may have constant atmospheres about them , and yet not discover that they have so , but by their operation upon one particular body , or those few which participate of that ; and since there are already ( as we have seen ) very differing wayes whereby bodies may appear to be exhaleable , it is not unlikely that there may be more and more bodies ( even of those that are solid and hard ) found to emit effluvia , as more and more wayes of discovering that they do so , shall either by chance or industry be brought to light . finis . the contents . experiment . about the raising of mercury to a great height in an open tube , by the spring of a litle included air. vvherein is set down the height the mercury was raisd to , p. . its sudden ascent upon the first suck , with the vibrations it makes before it settles : what proportion of height it has upon the several exuctions , and what height the mercury was at in the barometer at the time of the trials of this experiment . p. . . . as also what the quantity of the included air was , and how the experiment may be made use of against those , that in the explication of the torricellian experiment recur to a funiculus or a fuga vacui . p. . experiment . shewing , that much included air rais'd mercury in an open tube , no higher than the weight of the atmosphere may in a baroscope . the reason that induc'd the authour to think it would be so : the successe of the experiment , and notice taken of the great force of the spring of the air then when it could not raise the mercury any higher . . . . experiment . shewing that the spring of the included air will raise mercury to almost equal heights in very unequal tubes . of the allowance that is to be made for the weakning of the spring of the air , whilst it expands it self into the place of a larger cylinder of mercury , together with the reason why this and the former experiment were not tried in water , as also an account of an adventitious spring that was superadded to the air by heat . . . experiment . about a new hydraulo-pneumatical fountain , made by the spring of uncompress'd air. . several directions for it . . . the uses to be made of it ; as in hydraulo-pneumaticks , or to shew by what degrees the air restores it self to its spring , or especially to find what kind of line the salient water describes in rarified air. . &c. experiment . about a way of speedily breaking flat glasses by the weight of the atmosphere . experiment . shewing , that the breaking of glass plates in the foregoing experiment , need not to be ascrib'd to the fuga vacui . experiment . about a convenient way of breaking blown bladders by the spring of the air included in them . and of the usefulness of this experiment in other tryals . experiment . about the lifting up a considerable weight by the bare spring of a litle air included in a bladder . vvith a hint that this may not be unserviceable for the explanation of the muscles . experiment . about the breaking of hermetically seal'd bubbles of glass by the bare spring of their own air. that they broke not presently , and what the reason might be of the slowness of that effect . ib. experiment . containing two or three tryals of the force of the spring of our air uncompress'd upon stable and even solid bodies , ( whereto t is external . ) several trials of it with different circumstances , that the vessels broke not here neither immediately upon the last exuction : with a note necessary for the practise of one of the trials . experiment . shewing , that mercury will in tubes be raised by suction no higher than the weight of the atmosphere is able to impell it up . the principle of the schoolmen of a fuga vacui shewn to be insufficient , as also the supposition of a funiculus . &c. some particulars to be taken notice of concerning the exhausting a siphon , an instrument of frequent use in these experiments . . experiment . about the differing heights whereto liquors will be elevated by suction , according to their several specifick gravities . notice given , that the proportion of the specifick gravity of mercury to water is not quite as to . . the notion of a fuga vacui unreasonable . ib. the use that may be made of this experiment in the estimating the gravity of several liquors , with some tryals thereupon . . . experiment . about the heights to which water and mercury may be raised , proportionably to their specifick gravities , by the spring of the air. experiment . about the heights answerable to their respective gravities , to which mercury and water will subside , upon the withdrawing of the spring of the air. . &c. vvith notice of the difficulty of the trial , and the allowance that must be made in it . ib. experiment . about the greatest height to which water can be rais'd by attraction or sucking-pumps . the motives for the trying of it , the apparatus . . the height of the water , the same compar'd to that of the quick-silver at the same time in a baroscope , and examin'd according to the proportion of their specifick gravities . . &c. some circumstances delivered , that induced the author to think the trial was exactly enought performed . . an intimation given of the difference there may be in these kind of trials from the varying weight of the atmosphere . a mistake of vvriters of hydraulicks in the conceit of carrying water over never so high mountains . . experiment . about the bending of a springy body in the exhausted receiver . no alteration of the spring discovered . experiment . about the making of mercurial , and other gages , whereby to estimate how the receiver is exhausted . several gages mentioned . . one preferr'd and describ'd , and directions for it given . . &c. two other gages useful , when t is not requir'd the engine should be very much exhausted . . experiment . about an easie way to make the pressure of the air sensible to the touch of those that doubt of it . vvith a caution in using of it . experiment . about the subsidence of mercury in the tube of the torricellian experiment to the level of the stagnant mercury . some confirmations of what had been said in the first treatise of the physico-mechanical experiments . exp. . . experiment . shewing , that in tubes open at both ends , when no fuga vacui can be pretended , the weight of water will raise quick-silver no higher in slender than in larger pipes . two tryals , one with tubes of several bignesses open at both ends . . . the other with them after the torricellian way . . experiment . of the heights at which pure mercury , and mercury amalgam'd with tin , will stand in barometers . a note concerning the inconvenience , if the amalgam be too thick : the use that may be made of this experiment , to discover how much two mixt bodies penetrate one another , as also to further illustrate that the height of the liquors in the torricellian experiment depends upon the aequilibrium with the outward air. experiment . wherein is proposed away of making barometers , that may be transported even to distant countries . the figure the barometer is to be of , the way of filling it , putting it into a frame , and securing it from the harm the mercury its self might do in the transportation by its moving up and down in the upper empty part . . . &c. the great serviceableness of this instrument , with an intimation of others of a different kind . . a postscript advertising , that there has been since some difference found betwixt an ordinary baroscope and these travailing ones , with a guess at the reason of it , and that for all this the portable baroscopes may be serviceable . . experiment . confirming , that mercury in a barometer will be kept suspended higher at the top , than at the bottom of a hill. on which occasion something is noted about the height of mountains , especially the pic of tenariff . other authors opinions about it examined . a more moderate height allow'd than that asserted by ricciolus . . . with a consideration to be had in the measuring the altitude of mountains distant from the sea. experiment . shewing , that the pressure of the atmosphere may be exercis'd enough to keep up the mercury in the torricellian experiment , though the air presse upon it at a very small orifice . experiment . shewing , that an oblique pressure of the atmosphere may suffice to keep up the mercury at the wonted height in the torricellian experiment , and that the spring of a litle included air may do the same . vvhat use may be made of the former experiment for a portable baroscope . . experiment . about the making of a baroscope ( but of litle practical use ) that serves but at certain times . the argument it affords against a fuga vacui . ib. experiment . about the ascension of liquors in very slender pipes in an exhausted receiver . experiment . about the great and seemingly spontaneous ascension of water in a pipe fill'd with a compact body , whose particles are thought incapable of imbibing it . by it an explication that has been made of the cause of filtration examined . a probable cause of the ascension of sap into trees hence suggested . an attempt to make a syphon , that should run of it self without suction . . experiment . of the seemingly spontaneous ascension of salts along the sides of glasses , with a conjecture at the cause of it . experiment . about an attempt to measure the gravity of the cylinders of the atmosphere , so as that it may be exprest by known and common weights . wherein also the specifick gravities of mercury and vvater are compared . experiment . about the attractive virtue of the loadstone in an exhausted receiver . experiment . shewing , that when the pressure of the external air is taken off , t is very easie to draw up the sucker of a syringe , though the hole , at which the air or vvater should succeed , be stopt . the first tryal . . the d tryal , containing a variation of the foregoing . experiment . about the opening of a syringe , whose pipe was stopt in the exhausted receiver , and by the help of it making the pressure of the air lift up a considerable weight . experiment . shewing , that the cause of the ascension of liquors in syringes is to be derived from the pressure of the air. exemplified in three several tryals . . . experiment . shewing , that upon the pressure of the air depends the sticking of cupping-glasses to the fleshy parts they are apply'd to . experiment . about the making , without heat , a cupping-glass to lift up a great weight . experiment . shewing , that bellows , whose nose is very well stopt , will open of themselves , when the pressure of the external air is taken off . experiment . about an attempt to examine the motions and sensibility of the cartesian materia subtilis , or the aether with a pair of bellows ( made of a bladder ) in the exhausted receiver . experiment . about a farther attempt to prosecute the inquiry propos'd in the fore-going . experiment . first with a syringe and a feather . . . &c. then with a syringe in water . if there be an aether , what kind of body it must be , with a confirmation of the th experiment . experiment . about the falling , in the exhausted receiver , of a light body , fitted to have its motion visibly varied by a small resistance of the air. a design mentioned to try this way , what the degrees of celerity would be of descending bodies in an exhausted receiver . a caution given concerning this present experiment . ib. directions given , which way to lengthen receivers for the trial of this and other experiments . experiment . about the propagation of sounds in the exhausted receiver . a contrivance describ'd necessary for this and divers experiments . the trial perform'd by it . . another trial with an alarum watch . . an assertion of mersennus examined : a proposal of his shewn to be unpracticable . . a mention of some other trials designed concerning sound . . experiment . about the breaking of a glass-drop in an exhausted receiver . vvherein an hypothesis , ascribing the cause of the breaking of them to the force of the external air , is examined . ib. experiment . about the production of light in the exhausted receiver . experiment . about the production of a kind of halo , and colours in the exhausted receiver . the reason of it proposed , with a suggestion that the same cause might have been of that apparition of light mentionea in the formerly publisht experiments . . experiment . about the production of heat by attrition in the exhausted receiver . experiment . about the slaking of quick-lime in the exhausted receiver . experiment . about an attempt made to measure the force of the spring of included air , and examine a conjecture about the difference of its strength in unequally broad mouth'd vessels . the first trial by a syringe ; another different trial ; the successe of which is summarily related , and the way of making the experiment delivered : . &c. with the above named conjecture about &c. experiment . about an easie way of making a small quantity of included air raise in the exhausted receiver or pound , or a greater weight . experiment . about the weight of air. two notes in prosecution of the th of the already published experiments , concerning the estimating the weight of the air , by the help of a seal'd bubble . . another tryal , by weighing the receiver its self . . &c. an advertisement of the variation of the gravity of the air , and that by experiments made at different times or places there are obtain'd different proportions betwixt it and water . . experiment . about the disjoyning of two marbles ( not otherwise to be pull'd a sunder without a great weight ) by withdrawing the pressure of the atmosphere . notes &c. about the atmospheres of consistent bodies ( here below : ) an advertisement , shewing the reason why these notes are annex'd , and what discourse they belong to . . the proemium . that there are such atmosphares , prov'd à priori , both from the atomical and cartesian hypothesis . demonstrated by particular examples in several bodies . . in such as are most unlikely to emit effluvia , as first in very cold bodies . . . in very ponderous . . &c. in very solid and hard bodies . . &c. and lastly , in those that are most fixt . where the argument of des-cartes against electrical emanations , drawn from the fixednesse of glass , is examined . observations about the exciting the electricity of bodies , as that of amber by the sun , and that of glass by the heat of the fire . the considerations that may induce us to believe , that very many other bodies , not yet discovered to do so , emit their effluviums . . &c. m r boyle's continuation of experiments of the air. the viii . plate plate the vii . the v plate the plate . the iv plate the iii plate . notes, typically marginal, from the original text notes for div a -e seneca quaest . nat . lib. . c. . notes for div a -e see plate the iii figure the see the latter part of the following experiment . see plate the figure the . the same reasons which made instrumental musick fit for sacrifices in the apostles days make it fit still . pli. l. x. ep. sam. x. . chr. xxv . ● . exp. . pag. . * the place here meant is a passage in the author's examen of mr. hobbs his dialogue about the air. see plate the fig. the and the annotations at the close of this experiment . see plate the figure the plate the fig. the see plate the figure the * in notes about the history of elasticity . see plate the figure the exper. the xvii . pag. the , and . the like consideration i since found to have been had , before me , by the learned ricciolus . this was ( if i forget not ) about the later end of the year . see the fig. of the plate see plate the fig. the see plate the figure the see plate the fig. the * page the . . see plate the figure the see the figure last referr'd to . the contrivance here mentioned may be conceiv'd , by considering the figure belonging to the . experiment . * pag. . &c ▪ see plate the fig. the * expe. the vth. see plate the figure the see plate the fig. the * viz. the xxxvi . april the . . may. . . a in the hydrostatical paradoxes . b in an appendix to those paradoxes . c this method was omitted in the english edition of the newly mentioned appendix , but not in the latin version . * experiment the xxxi . see also the cause of this phaenomenon discours'd of in the authors history of fluidity and firmness . * dr. h. m. in the d . chap. of the d . book of the new edition ( in folio ) of his antidote against atheism . an attempt to prove the motion of the earth from observations made by robert hooke ... hooke, robert, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing h estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) an attempt to prove the motion of the earth from observations made by robert hooke ... hooke, robert, - . [ ], p., [ ] leaves of plates : ill. printed by t.r. for john martyn ..., london : . reproduction of original in british library. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . gravitation. earth -- rotation. - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - melanie sanders sampled and proofread - melanie sanders text and markup reviewed and edited - pfs batch review (qc) and xml conversion an attempt to prove the motion of the earth from observations made by robert hooke fellow of the royal society . senec. nat. qu. lib. . cap. . nè miremur tam tardè erui qua tam altè jacent . london , printed by t. r. for john martyn printer to the royal society , at the bell in st. pauls church-yard . . to the truly honorable sir john cutler knight and baronet , my worthy patron . sir , among several eminent marks of your greatness of mind for promoting the publick good , that of your bounty for the advancement of experimental and real knowledge , by the founding a physico-mechanical lecture , deserves to be recorded as one , and more especially by me whom you have honoured by establishing your first lecturer . as an earnest of others more considerable shortly to follow , i here present you with one of my discourses in that employment , which though short and plain , conteins somewhat of information which the learned have hitherto desired , though almost with despair . as i hope their kind acceptance will produce their thanks to you to whom they are justly due , so your acceptance will incourage me in the further prosecution of these inquiries to approve my self , noble sir , your most obliged , and most humble servant from gresham colledge , march . . robert hooke . reader , i have formerly in the preface of my micrographia given the world an account of the founding a physico-mechanical lecture in the year , by sir john cutler , for the promoting the history of nature and of art. in prosecution thereof , i have collected many observations both of the one and the other kind , and from time to time ( as obliged ) i have acquainted the royal society at their publick meetings , both at gresham colledge and arundel house therewith , by discourses and lectures thereupon . now in order to the further promoting the end and design of this lecture , i have complyed , with the desire of several of my friends ( though otherwise not thereunto obliged ) to commit divers of those discourses to the publick , though of themselves for the most part incompleat , and essayes or attempts only upon several subjects which have no dependencie or coherencie one with another . in the doing hereof , i design to avoid any kind of method or order that may require apologies , prefaces , or needless repetitions of what is already known , or might have been said upon that occasion , or may necessitate me to follow this or that subject , that doth not some way or other offer it self as it were , and prompt me to the consideration thereof . but because they may possibly admit of some better order hereafter , i design to print them all of the same volume , that so they may be , when ranged , either stitched or bound together , and may , as occasion requires , be referred to under the title of their number and page . this way i chuse as the best for promoting the design of this lecture ; for as there is scarce one subject of millions that may be pitched upon , but to write an exact and compleat history thereof , would require the whole time and attention of a mans life , and some thousands of inventions and observations to accomplish it : so on the other side no man is able to say that he will compleat this or that inquiry , whatever it be , ( the greatest part of invention being but a luckey hitt of chance , for the most part not in our own power , and like the wind , the spirit of invention bloweth where and when it listeth , and we scarce know whence it came , or whether 't is gone . ) 't will be much better therefore to imbrace the influences of providence , and to be diligent in the inquiry of every thing we meet with . for we shall quickly find that the number of considerable observations and inventions this way collected , will a hundred fold out-strip those that are found by design . no man but hath some luckey hitts and useful thoughts on this or that subject he is conversant about , the regarding and communicating of which , might be a means to other persons highly to improve them . whence 't were much to be wished , that others would take this method in their publications , and not torment their readers with such nauseous repetitions , and frivolous apologies , as method and volumes do necessitate them to ; but would rather inrich the store-house of art and nature with choice and excellent seed , freed from the chaff and dross that do otherwise bury and corrupt it . the communicating such happy thoughts and occurrences need not much take up a mans time to fit it for the press ; the relation being so much the better the plainer it is . and matter of fact being the kernel readers generally desire ( at least in these subjects ) it will be so much the readier for use if it be freed from the thick and hard shell of impertinences . this way also is more grateful both to the writer and the reader , who proceed with a fresh stomach upon variety , but would be weary and dull'd if necessitated to dwell too long upon one subject . there are other conveniencies also in this method of communication not less considerable then the former , amongst the rest the securing of inventions to their first authors , which 't is hardly possible to do by any other means ; for there are a sort of persons that make it their business to pump and spy out others inventions , that they may vend them to traders of that kind , who think they do ingenuously to print them for their own , since they have bought and paid for them . of this there have lately been some instances , and more may be expected , if this way prevent not . when things cannot be well explained by words only ( which is frequent in mathematical and mechanical discourses ) i adde schemes and delineatious descriptions of that kind being easier to be made and understood . as near as i can i omit the repeating things already printed , and indeavour to deliver such as are new and my own ▪ being my self best pleased with such usage from other authors . i have begun with a discourse composed and read in gresham colledge in the year . when i designed to have printed it , but was diverted by the advice of some friends to stay the repeating the observation , rather then publish it upon the experience of one year only . but finding that sickness hath hitherto hindered me from repeating the tryals , and that some years observations have already been lost by the first delay : i do rather hast it out now , though imperfect , then detain it for a better compleating , hoping it may be at least a hint to others to prosecute and compleat the observation , which i much long for . this first discourse is upon an observation of nature , and may therefore be properly referred to that head , though it contein also somewhat of the improvement of art : the second speedily to follow , will more properly be referrable to artificial improvements , though it will contein also many observations of nature ; and i design alwayes to make them follow each other by turns , and as 't were to interweave them , being apart but like the warp or woof before contexture , unfit either to cloth , or adorn the body of philosophy . an attempt to prove the motion of the earth by observations . whether the earth move or stand still hath been a problem , that since copernicus revived it , hath much exercised the wits of our best modern astronomers and philosophers , amongst which notwithstanding there hath not been any one who hath found out a certain manifestation either of the one or the other doctrine . the more knowing and judicious have for many plausible reasons adhered to the copernican hypothesis : but the generality of others , either out of ignorance or prejudice , have rejected it as a most extravagant opinion . to those indeed who understand not the grounds and principles of astronomy , the prejudice of common converse doth make it seem so absurd , that a man shall as soon perswade them that the sun doth not shine , as that it doth not move ; and as easily move the earth as make them believe that it do's so already . for such persons i cannot suppose that they should understand the cogency of the reasons here presented , drawn from the following observations of parallax , much less therefore can i expect their belief and assent thereunto ; to them i have only this to say , 't is not here my business to instruct them in the first principles of astronomy , there being already introductions enough for that purpose : but rather to furnish the learned with an experimentum crucis to determine between the tychonick and copernican hypotheses . that which hath hitherto continued the dispute hath been the plausibleness of some arguments alledged by the one and the other party , with such who have been by nature or education prejudiced to this or that way . for to one that hath been conversant only with illiterate persons , or such as understand not the principles of astronomy and geometry , and have had no true notion of the vastness of the universe , and the exceeding minuteness of the globe of the earth in comparison therewith , who have confined their imaginations & fancies only within the compass and pale of their own walk and prospect , who can scarce imagine that the earth is globous , but rather like some of old , imagine it to be a round plain covered with the sky as with a hemisphere , and the sun , moon , and stars to be holes through it by which the light of heaven comes down ; that suppose themselves in the center of this plain , and that the sky doth touch that plain round the edges , supported in part by the mountains ; that suppose the sun as big as a sieve , and the moon as a chedder cheese , and hardly a mile off . that wonder why the sun , moon , and stars do not fall down like hail-stones ; and that will be martyr'd rather then grant that there may be antipodes , believing it absolutely impossible , since they must necessarily fall down into the abyss below them : for how can they go with their feet towards ours , and their heads downwards , without making their brains addle . to one i say , thus prejudiced with these and a thousand other fancies and opinions more ridiculous and absurd to knowing men , who can ever imagine that the uniformity and harmony of the celestial bodies and motions , should be an argument prevalent to perswade that the earth moves about the sun : whereas that hypothesis which shews how to salve the appearances by the rest of the earth and the motion of the heavens , seems generally so plausible that none of these can resist it . now though it may be said , 't is not only those but great geometricians , astronomers and philosophers have also adhered to that side , yet generally the reason is the very same . for most of those , when young , have been imbued with principles as gross and rude as those of the vulgar , especially as to the frame and fabrick of the world , which leave so deep an impression upon the fancy , that they are not without great pain and trouble obliterated : others , as a further confirmation in their childish opinion , have been instructed in the ptolomaick or tichonick system , and by the authority of their tutors , over-awed into a belief , if not a veneration thereof : whence for the most part such persons will not indure to hear arguments against it , and if they do , 't is only to find answers to confute them . on the other side , some out of a contradicting nature to their tutors ; others , by as great a prejudice of institution ; and some few others upon better reasoned grounds , from the proportion and harmony of the world , cannot but imbrace the copernican arguments , as demonstrations that the earth moves , and that the sun and stars stand still . i confess there is somewhat of reason on both sides , but there is also something of prejudice even on that side that seems the most rational . for by way of objection , what way of demonstration have we that the frame and constitution of the world is so harmonious according to our notion of its harmony , as we suppose ? is there not a possibility that the things may be otherwise ? nay , is there not something of probability ? may not the sun move as ticho supposes , and the planets make their revolutions about it whilst the earth stands still , and by its magnetism attracts the sun , and so keeps him moving about it , whilst at the same time ☿ and ♀ move about the sun , after the same manner as ♄ and ♃ move about the sun whilst the satellites move about them ? especially since it is not demonstrated without much art and difficulty , and taking many things for granted which are hard to be proved , that there is any body in the universe more considerable then the earth we tread on . is there not much reason for the hypothesis of ticho at least , when he with all the accurateness that he arrived to with his vast instruments , or riccioli , who pretends much to out-strip him , were not able to find any sensible parallax of the earths orb among the fixt stars , especially if the observations upon which they ground their assertions , were made to the accurateness of some few seconds ? what then , though we have a chimera or idea of perfection and harmony in that hypothesis we pitch upon , may there not be a much greater harmony and proportion in the constitution it self which we know not , though it be quite differing from what we fancy ? probable arguments might thus have been urged both on the one and the other side to the worlds end ; but there never was nor could have been any determination of the controversie , without some positive observation for determining whether there were a parallax or no of the orb of the earth ; this ticho and riccioli affirm in the negative , that there is none at all : but i do affirm there is no one that can either prove that there is , or that there is not any parallax of that orb amongst the fixt stars from the suppellex of observations yet made either by ticho , riccioli , or any other writer that i have yet met with from the beginning of writing to this day . for all observators having hitherto made use of the naked eye for determining the exact place of the object , and the eye being unable to distinguish any angle less then a minute , and an observation requisite to determine this requiring a much greater exactness then to a minute , it doth necessarily follow that this experimentum crucis was not in their power , whatever either ticho or riccioli have said to the contrary , and would thence overthrow the copernican system , and establish their own . we are not therefore wholly to acquiess in their determination , since if we examine more nicely into the observations made by them , together with their instruments and wayes of using them , we shall find that their performances thereby were far otherwise then what they would seem to make us believe . the controversie therefore notwithstanding all that hath been said either by the one or by the other party , remains yet undetermined , whether the earth move above the sun , or the sun about the earth ; and all the arguments alledged either on this or that side , are but probabilities at best , and admit not of a necessary and positive conclusion . nor is there indeed any other means left for humane industry to determine it , save this one which i have endeavoured to make ; and the unquestionable certainty thereof is a most undenyable argument of the truth of the copernican systeme ; and the want thereof hath been the principal argument that hath hitherto somewhat detained me from declaring absolutely for that hypothesis , for though it doth in every particular almost seem to solve the appearances more naturally and easily , and to afford an exceeding harmonious constitution of the great bodies of the world compared one with another , as to their magnitudes , motions , and distances , yet this objection was alwayes very plausible to most men , that it is affirmed by such as have written more particularly of this subject , that there never was any sensible parallax discovered by the best observations of this supposed annual motion of the earth about the sun as its center , though moved in an orb whose diameter is by the greatest number of astronomers reckoned between and hundred diameters of the earth : though some others make it between and thousand ; others between and ; and others between and thousands ; and i am apt to believe it may be yet much more , each diameter of the earth being supposed to be between and thousand english miles , and consequently the whole being reduced into miles , if we reckon with the most , amounting to millions of english miles . it cannot , i confess , but seem very uncouth and strange to such as have been used to confine the world with less dimensions , that this annual orb of the earth of so vast a magnitude , should have no sensible parallax amongst the fixt stars , and therefore 't was in vain to indeavour to answer that objection . for it is unreasonable to expect that the fancies of most men should be so far streined beyond their narrow dimensions , as to make them believe the extent of the universe so immensly great as they must have granted it to be , supposing no parallax could have been found . the inquisitive jesuit riccioli has taken great pains by arguments to overthrow the copernican hypothesis , and is therein so earnest and zealous , that though otherwise a very learned man and good astronomer , he seems to believe his own arguments ; but all his other arguments might have been spared as to most men , if upon making observations as i have done , he could have proved there had been no sensible parallax this way discoverable , as i believe this one discovery will answer them , and more , if so many can be thought of and produced against it . though yet i confess had i fail'd in discovering a parallax this way , as to my own thoughts and perswasion , the almost infinite extension of the universe had not to me seem'd altogether so great an absurdity to be believed as the generality do esteem it ; for since 't is confessedly granted on all hands the distance of the fixt stars is meerly hypothetical , and not founded on any other ground or reason but fancy and supposition , and that there never was hitherto any parallax observed , nor any other considerable argument to prove the distances supposed by such as have been most curious and inquisitive in that particular , i see no argument drawn from the nature of the thing that can have any necessary force in it to determine that the said distance cannot be more then this or that , whatever it be that is assigned . for the same god that did make this world that we would thus limit and bound , could as easily make it millions of millions of times bigger , as of that quantity we imagine ; and all the other appearances except this of parallax would be the very same that now they are . to me indeed the universe seems to be vastly bigger then 't is hitherto asserted by any writer , when i consider the many differing magnitudes of the fixt stars , and the continual increase of their number according as they are looked after with better and longer telescopes . and could we certainly determine and measure their diameters , and distinguish what part of their appearing magnitude were to be attributed to their bulk , and what to their brightness , i am apt to believe we should make another distribution of their magnitudes , then what is already made by ptolomy , ticho , kepler , bayer , clavius , grienbergerus , piff , hevelius and others . for supposing all the fixt stars as so many suns , and each of them to have a sphere of activity or expansion proportionate to their solidity and activity , and a bigger and brighter bodied star to have a proportionate bigger space or expansion belonging to it , we should from the knowledge of their diameters and brightnesses be better able to judge of their distances , and consequently assign divers of them other magnitudes then those already stated : especially since we now find by observations , that of those which are accounted single stars , divers prove a congeries of many stars , though from their near appearing to each other , the naked eye cannot distinguish them ; such as those stars which are called nebulous , and those in orion sword , and that in the head of aries , and a multitude of others the telescope doth now detect . and possibly we may find that those twenty magnitudes of stars now discovered by a fifteen foot glass , may be found to increase the magnitude of the semidiameter of the visible world , fourty times bigger then the copernicans now suppose it between the sun and the fixt stars , and consequently sixty four thousand times in bulk . and if a telescope of double or treble the goodness of one of fifteen should discover double or treble the said number of magnitudes , would it not be an argument of doubling or trebling the former diameter , and of increasing the bulk eight or twenty seven times . especially if their apparent diameters shall be found reciprocal to their distances ( for the determination of which i did make some observations , and design to compleat with what speed i am able . ) but to digress no further , this grand objection of the anti-copernicans , which to most men seem'd so plausible , that it was in vain to oppose it , though , i say , it kept me from declaring absolutely for the copernican hypothesis , yet i never found any absurdity or impossibility that followed thereupon : and i alwayes suspected that though some great astronomers had asserted that there was no parallax to be found by their observations , though made with great accurateness , there might yet be a possibility that they might be mistaken ; which made me alwayes look upon it as an inquiry well worth examining : first , whether the wayes they had already attempted were not subject and lyable to great errors and uncertainties : and secondly , whether there might not be some other wayes found out which should be free from all the exceptions the former were incumbred with , and be so far advanced beyond the former in certainty and accurateness , as that from the diligent and curious use thereof , not only all the objections against the former might be removed , but all other whatsoever that were material to prove the ineffectualness thereof for this purpose . i began therefore first to examine into the matter as it had already been performed by those who had asserted no sensible parallax of the annual orb of the earth , and quickly found that ( whatever they asserted ) they could never determine whether there were any or no parallax of this annual orb ; especially if it were less then a minute , which kepler and riccioli hypothetically affirm it to be : the former making it about twenty four seconds , and the latter about ten . for though ticho , a man of unquestionable truth in his assertions , affirm it possible to observe with large instruments , conveniently mounted and furnished with sights contrived by himself ( and now the common ones for astronomical instruments ) to the accurateness of ten seconds ; and though riccioli and his ingenious and accurate companion grimaldi affirm it possible to make observations by their way , with the naked edge to the accurateness of five seconds ; yet kepler did affirm , and that justly , that 't was impossible to be sure to a less angle then seconds : and i from my own experience do find it exceeding difficult by any of the common sights yet used to be sure to a minute . i quickly concluded therefore that all their endeavours must have hitherto been ineffectual to this purpose , and that they had not been less imposed on themselves , then they had deceived others by their mistaken observations . and this mistake i found proceeded from divers inconveniencies their wayes of observations were lyable to . as first from the shrinking and stretching of the materials wherewith their instruments were made , i conceive a much greater angle then that of a minute may be mistaken in taking an altitude of fifty degrees . for if the instruments be made of wood , 't is manifest that movst weather will make the frame stretch , and dry weather will make it shrink a much greater quantity then to vary a minute : and if it be metal , unless it be provided for in the fabrick of the instrument accordingly , the heat of summer , when the summer observations are to be made , will make the quadrant swell , and the cold of winter will make it shrink much more then to vary a minute : both which inconveniencies ought to be removed . next the bending and warping of an instrument by its own weight , will make a very considerable alteration . and thirdly , the common way of division is also lyable to many inconveniencies : and 't is hardly possible to ascertain all the subdivisions of degrees into minutes for the whole quadrant , though that be not altogether impossible . but i will suppose that they did foresee , and in some manner prevent all these inconveniencies , especially ticho and riccioli , who seem to have been aware thereof . but there was one inconvenience which was worse then all the rest , which they seem not to have been sufficiently sensible of , from whence proceeded all their own mistakes , and their imposing upon others , and that was from their opinion that the sight of the naked eye was able to distinguish the parts of the object as minutely as the limb of the quadrant ( of what largeness soever ) was capable of divisions ; whereas 't is hardly possible for any unarmed eye well to distinguish any angle much smaller then that of a minute : and where two objects are not farther distant then a minute , if they are bright objects , they coaless and appear one , though i confess , if they be dark objects , and a light be interposed , the distance between them shall be visible , though really much less then a second ; and yet notwithstanding , my first assertion stands good ; for though a bright object , as a candle or light at a distance , or a star , or the like , can be seen by the eye , though its body do really not subtend an angle of one third , yet it proceeds from a radiation ( that is , from reflection and refraction together ) in the air and in the eye , whereby the body thereof is represented to the naked eye some hundred times bigger then it really is . that this is so , any one that will but carefully examine will find it true . it was , i doubt not , their extraordinary desire and care to be exact , that caused them to make their instruments so large , and to subdivide them to such an exactness , as to distinguish , if possible , to seconds ; and i question not but that they used their utmost indeavour in directing the sight to the object : but since the naked eye cannot distinguish an angle much smaller then a minute , and very few to a whole minute , all their charge and trouble in making and managing large instruments , and in calculating and deducing from them , was as to this use in vain . hence i judged that whatever mens eyes were in the younger age of the world , our eyes in this old age of it needed spectacles ; and therefore i resolved to assist my eyes with a very large and good telescope , instead of the common sights , whereby i can with ease distinguish the parts of an object to seconds : and i question not but that this way may be yet made capable of distinguishing much more curiously , possibly even to some few thirds . this invention removed that grand inconvenience which all former observations were spoiled with : but there remained yet further this difficulty , how to make an instrument large enough for this purpose , that i might be assured did not shrink , nor warp , nor stretch so much as to vary a second ; for such is the nature of all materials that can be made use of for instruments of the bigness i designed this , that 't is almost impossible to make a moveable instrument that shall not be subject to a variation of divers seconds : it was therefore my next inquiry where i might fix this archimedean engine that was to move the earth . for the doing of which , i knew 't was in vain to consult with any writer or astronomer , having never then heard of any person that had ever before that time had any thoughts thereof : and when i first propounded it to the royal society , 't was look'd upon as a new thought , and somewhat extravagant , and hardly practicable , until upon hearing my explication , and the various wayes how it might be reduced into practise , it was at length judged possible , and desirable to be tryed . i propounded therefore to them the several ways that it was possible to be performed , and what method was to be observed in every one of them , and somewhat of the conveniencies and inconveniencies in each of them ; for having seriously meditated upon the inquiry , i quickly thought of many expedients for the doing thereof . as first , i had thoughts of making use of some very great and massy tower or wall that were well setled , or of some large rock or hill whereunto i might fix my glasses , so as to take the exact altitude of some eminent star near the pole of the ecliptik , when at its greatest height , at two differing times of the year ; to wit , about the summer and winter solstice , to see if possibly i could discover any difference of altitude between the first and second observation . but to accomplish this ( besides the vast difficulty there would have been to have measured such an angle to the accurateness requisite , if at least it were desired to have the angle of altitude to minutes and seconds , which ought also to have been repeated as oft as any observation had been made for fear of setling or swelling , &c. ) i was destitute of such a convenience near my habitation ; besides , had i had my wish , i found that 't was lyable to an inconvenience that would wholly overthrow my whole design , which i knew not well how to avoid : namely , to that which hath hitherto made even the very best observations of parallaxes ineffectual and uncertain , the refraction of the air or atmosphere , which though it could have been but very little at the greatest altitude of the pole of the ecliptick , yet it might have been enough plausibly to have spoiled the whole observation , and to have given the anti-copernicans an opportunity of evading the arguments taken from it , especially upon the account of the differing constitution of the atmosphere in june and december , which might have caused so much a greater refraction of the same altitude at one time then another , as would have been sufficient to have made this observation ineffectual for what it was designed . adde to this , that it would have been no easie matter to have set the glasses or telescope exactly against the meridian , so as to see the highest altitude of any star near the pole of the ecliptick distinctly to a second . the like difficulties i found if observations were made of the greatest altitude of the pole of the ecliptick in june and december , or the least altitude of the same in december and june . for besides all the uncertainties that the instruments , be they what they will , are liable to , the grand inconvenience of the refraction of the air , which is enough to spoil all observations if it be intermixed with uncertainty , in the former is considerable , and in the later intolerable . having therefore examined the wayes and instruments for all manner of astronomical observations hitherto made use of , and considered of the inconveniencies and imperfections of them ; and having also duly weighed the great accurateness and certainty that this observation necessarily required : i did next contrive a way of making observations that might be free from all the former inconveniencies and exceptions , and as near as might be , fortified against any other that could be invented or raised against it . this way then was to observe by the passing of some considerable star near the zenith of gresham colledge , whether it did not at one time of the year pass nearer to it , and at another further from it : for if the earth did move in an orb about the sun , and that this orb had any sensible parallax amongst the fixt stars ; this must necessarily happen , especially to those fixt stars which were nearest the pole of the ecliptick . and that this is so , any one may plainly perceive if he consider the annexed scheme , fig. i. where let s represent the sun placed as it were in the center of the planetary orbs , abcd an imaginary orb of the fixt stars of the first magnitude , whose center for demonstration sake we will suppose the sun. let ♈ ♋ ♎ ♑ represent the orb in which the earth is supposed to move about the sun , obliquely projected on the paper . let ♑ represent the earth in capricorn , and ♋ the earth in cancer , let . . represent the imaginary axis of the earth , keeping continually a parallelism to its self , and let ♑ abcd ♋ represent an imaginary plain passing through the center of the star at d in the solstitial colure , and the two centers of the earth in ♑ and ♋ , and c represent the zenith point of gresham colledge at noon , when the earth is in cancer , and a the zenith point of the said colledge at midnight in the aforesaid orb abcd when the earth is in capricorn , 't is manifest therefore that since the poles of the earth , the poles of the ecliptick , and the zenith points of the earth at noon , when in cancer , and at midnight , when in capricorn , are all in the same plain ; and that the axis of the earth keeps alwayes its parallelism , and that the angles made by the perpendiculars of gresham colledge , with the axes are alwayes the same , that the aforesaid perpendiculars of the said colledge shall be parallel also one to another , and consequently denote out two points in the abovesaid orb a and c as far distant from each other as the parallel lines a ♑ and c ♋ are , and consequently the point a shall be farther from the star in d , and the point c shall be nearer to it , when in the meridian near the zenith of london , and consequently if the said star be observed when in the meridian of the place abovesaid , if there be any such difference considerable , it may be found if convenient instruments and care be made use of for the observation thereof : and the difference between the angle a ♑ d , and the angle c ♋ d , will give the parallactical angle ♑ d ♋ of the orb of the earth to the fixt star d of the first magnitude . the same demonstration will hold mutatis mutandis , supposing the star be not in the meridian or plain abovesaid , but in some other meridian , as any one upon well considering the nature of the thing it self may easily prove , if the observation be made when the zenith passes by the star at midnight , and at mid-day . but the nearer the zenith of the place of observation passeth to the pole point of the ecliptick , the better ; the angle of parallax being still the more sensible . therefore the best place to compleat this observation were in some place under the polar circles , as in iseland , where the zenith of the place at the times abovesaid , must consequently pass at one time to the north side of the pole of the ecliptick , and at the other on the south side , and the zenith of march and sept. must pass through the very pole-point it self . now it falling out so , that there is no considerable star in that part of the heavens nearer the above said plain , and nearer the zenith point of gresham colledge in that plain , then the bright star in the head of the dragon , i made choice of that star for the object by which i designed to make this observation , finding the zenith point of gresham colledge to pass within some very few minutes of the star it self ; the declination thereof according to riccioli being ° . ′ . ″ . and the plain the star and pole of the world , making an angle with the aforesaid plain but of ° . . , the right ascention thereof being according to riccioli ° . ′ . ″ . and that this may be made a little plainer , let us suppose in the third figure , the north part of the heavens projected stereographical upon a plain to which the axis is perpendicular . let p represent the pole , e the pole of the ecliptick , l the bright star in the head of draco , and let accc represent an imaginary circle described by the zenith of gresham colledge among the fixt stars in june , and bddd a like circle described by the said zenith in december , and efff a like circle described as above in march , and ghhh in september . it is very evident that the true distances of the zeniths in that part of the meridian which is next the pole of the ecliptick , to wit , in the head of the constellation draco , shall be to the true distances of the said zeniths in that part which is furthest from the said pole , to wit , near the constellation of auriga in consequentia , as the sign of degrees to the sign of ° . ′ , and the variation of the zeniths , or the angle of parallax here at gresham colledge , to the angle of parallax in iseland , or any other place under the pole of the ecliptick , or artick circle is , as the sign of seventy five to the sign of ninety or the radius . this will be very evident if we consider in the second scheme ; ab to represent the diameter of the great orb : ac and bd the perpendiculars of iseland , or some other place under the polar circle . ga , hb the perpendiculars of gresham colledge in draco : and la , mb the perpendiculars of the same place to the solstitial colure near auriga , the several distances cd , gh , ik , lm , will be as the signs of ° ° ° . ′ ° . ′ . to wit , as the lines or cords ab . ao . pb . qb . i might have made observations of the distances of the transits of our zenith from any other star as well as from this of draco , and the same phenomena might have been observed , taking care to make one of the observations when the star is in the zenith at midnight , and the other when the same star is in the zenith at noon or mid-day ; and upon this account when i next observe , i design to observe the transits of our zenith by benenaim , or the ultima caudae ursae majoris , it being a star of the second magnitude , and having almost as much declination as gresham colledge hath latitude . the principal dayes of doing which will be about the of april , when our zenith passeth by the said star at midnight , and the of october , when it passeth by it at noon or mid-day : the reason of all which will be sufficiently manifest to any one that shall well consider the preceeding explanation . this star i would the rather observe , because as it is placed so as that the parallax thereof will be almost as great as of the pole of the ecliptick in iseland , or under the artick circle , so it being a star of the second magnitude , and consequently perhaps as near again as one of the fourth , the angle of parallax will be near about twice as big , and the star it self much more easie to be seen in the day time . this will be very easie to be understood , if we consider in the first scheme the differing distances of the orb abcd , in which we may suppose the stars of the second magnitude to be fixt , and of the orb 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , in which we may suppose the stars of the fourth magnitude , and abcd in which we may suppose those of the third magnitude , and abcd in which we may suppose those of the first ; for if the stars are further and further removed from the sun , according as they appear less and less to us , the parallactical difference found by observation must necessarily be less and less , according as the observation is made of less and less stars . the reasons then why i made choice of this way of observing will be easie to any one that shall consider that hereby , first , i avoid that grand inconvenience wherewith all ancient and modern observations have been perplext , and as to parallax insignificant , and that is the refraction of the air or atmosphere . how great an inconvenience that was is obvious , since 't is certainly much greater at one time then another , and never at any certainty ; and secondly , 't is not equally proportionable , for sometimes the refraction is greater at some distance above the horizon , then in or nearer to the horizon it self , and sometimes the quite contrary , which i have very often observed ; and this to so exorbitant a difference , as to confound all hypothetical calculations of tables for this purpose . this ariseth from the uncertain and sudden variations of the air or atmosphere , either from heat and cold , from the thickness and thinness of vapours , from the differing gravity and levity , from the winds , currents , and eddyes thereof , all which being not so well understood by what way , and in what degree , and at what time they work and operate upon the air , must needs make the refraction thereof exceedingly perplext , and the reduction thereof to any certain theory fit for practice , a thing almost impossible . now if we are uncertain what part of the observed angle is to be ascribed to refraction , we are uncertain of the whole observation as far as the possible uncertainty of refraction . let me have but the liberty of supposing the refraction what i please , and of fixing the proportional decrease thereof according to the various elevation of the rayes above the horizon ; i will with ease make out all the visible phenomena of the universe , sun , moon , and stars , and yet not suppose them above a diameter of the earth distant . now in this observation there is no refraction at all , and consequently be the air thicker or thinner , heavier or lighter , hotter or colder , be it in summer or winter , in the night or the day , the ray continually passeth directly , and is not at all refracted and deflected from its streight passage . in the next place , by this way of observing i avoid all the difficulties that attend the making , mounting , and managing of great instruments : for i have no need of quadrant , sextant , or octant , nor of any other part or circle bigger then a degree at most ; nor have i need to take care of the divisions and subdivisions thereof , nor of the substance whether made of iron , brass , copper , or wood , nor whether the parts thereof shrink or swell , or bend or warp , to all which the best instruments hitherto made use of , have been some wayes or other lyable . and notwithstanding the vast care and expence of the noble ticho about the making , fixing , and using his great instruments ; yet i do not find them so well secured from divers of these inconveniences , but that they were still subject to some considerable irregularities . nay , notwithstanding the seemingly much greater curiosity and expense of hevelius , and his infinite labour and diligence in the compleating and using of his vast apparatus of astronomical instruments , i do not find them so well secured , but that some of the causes of errors that i have before mentioned , may have had a considerable effect upon them also ; especially if they were supposed to measure an angle to some few seconds , as i shall hereafter perhaps have more occasion to manifest . now , if ▪ the instruments of ticho and hevelius , ( who had certainly two of the most curious and magnificent collections of astronomical instruments that were ever yet got together or made use of ) were subject to these uncertainties , what shall we say of all that other farrage of trumpery that hath been made use of by most others ? we see therefore the necessity of the conjunction of physical and philosophical with mechanical and experimental knowledge , how lame and imperfect the study of art doth often prove without the conjunction of the study of nature , and upon what rational grounds it was that sir john cutler , the patron and founder of this lecture , proceeded in joyning the contemplation of them both together . the next thing was the instrument for the making of this observation , such a one as should not be lyable to any of the former exceptions , nor any other new ones that were considerable . to this purpose i pitched upon a telescope , the largest i could get and make use of , which i designed so to fix upright , as that looking directly upwards , i could be able certainly to observe the transits of any stars over or near the zenith , and furnishing it with perpendiculars and a convenient dividing instrument , i should be able not only to know exactly when the star came to cross the meridian , but also how far it crossed it from the center or zenith point of gresham colledge , either towards the north , or towards the south . all which particulars , how i performed , i shall now in order describe , and this somewhat the more distinctly , that such as have a desire to do the like , may be the more ready and better inabled to proceed with the same . first then ( finding a tube would be very troublesome to the rooms through which it past , especially if it were placed pretty far in the room , and that one wanted so free an access as was necessary if it were planted nigh the wall , and that there was no absolute necessity of such an intermediate tube , supposing there were a cell to direct the eye fixt to the eye glass , and that there were some short cell to carry the object glass in at the top , so as to keep it steady , when raised upward or let downwards , the light in the intermediate rooms not at all hindring , but rather proving of good use to this purpose for seeing the mensurator ) i opened a passage of about a foot square through the roof of my lodgings ( see the fourth figure ) and therein fixt a tube a a perpendicular and upright , of about ten or twelve foot in length , and a foot square , so as that the lower end thereof came through the ceiling , and was open into the chamber underneath : this tube i covered with a lid at the top q , housed so as to ▪ throw off the rain , and so contrived , as i could easily open or shut it by a small string ●op , which came down through the tube to the place where i observed . within this perpendicular tube a a , i made another small square tube b b , fit so as to slide upwards and downwards , as there was occasion , and by the help of a skrew to be fixt in any place that was necessary : within this tube in a convenient cell c , was fixt the object glass of the telescope ( that which i made use of was thirty six foot in length , having none longer by me , but one of sixty foot , and so too long to be made use of in my rooms ) the manner of fixing which was this : the glass it self was fixed into a cell or frame of brass , so exactly fitted to it , that it went in stiff ; and to fill up all the interstitia's , there was melted in hard cement ; this cell had a small barr that crossed under the center of the glass , or the aperture thereof ; in which barr were drill'd two small holes at equal distance from the middle of the glass , through which the upper ends of the two perpendiculars d d were fastned ; and in the fixing this brass cell or frame into the square tube that was to slide up and down , care was taken to make the barr lye as exactly north and south as could be , though that were not altogether so absolutely necessary to this observation . these perpendiculars d d fastned to the barr hung foot and better in length , and had at the lower ends of them two balls of lead e e as big as the silks could bear , by which the lowest parts of this instrument were adjusted , as i shall by and by explain . but first , i must acquaint the reader , that i opened a so perpendicularly under this tube a hole r r a foot square in the floor below , which with shutters could be closed or opened upon occasion ; by this means i had a perpendicular well-hole of about forty foot long , from the top of a to the lower floor s s. upon the second floor s s i fixed the frame that carried the eye-glass and the other apparatus fit to make this observation . i made then a stool or table , such as is described in the same fourth figure i h h i , having a hole through the top or cover thereof h h , of about nine inches over ; the middle of which i placed as near as i could perpendicularly under the middle of the object glass in the cell above , and then nailed the frame fast to the floor by the brackets i i , that it could not stir ; underneath the cover of this table i made a slider g g , in which was fixed in a cell an eye glass f , so as that i could through the eye glass moved to and fro , see any part of the hole in the table that i desired , without stirring the stool from its fixtness . this was necessary , because many stars which were forerunners of this star in draco , and served as warning to prepare for the approaching star , went pretty wide from the parallel that passed over our zenith ; by this means also i took notice of the star it self , at above half a degree distance from the zenith to the east , and so followed the motion of it with my eye glass , and also with my measuring clew , and at the same time told the seconds beat by a pendulum clock , and so was very well prepared to take notice of all things necessary to compleat the observation , but might have been otherwise surprised by the suddain approach and swift motion of the said star. the measuring instrument or mensurator was a round thin plate or circle of brass , delineated in the seventh figure , the aperture a b of which was about nine inches over , crossed in the middle by two very small hairs a b and c d , which served to shew the zenith point at e , by which the star was to pass ; there were also two other small hairs f g and i h drawn parallel to that which was to represent the east and west line , that past under our zenith , these cut the clue that represented the meridian , or north and south line at the places k and l , where the perpendicular points were made by the two long plumb lines : this instrument was produced on the side a to n , n e being made fifteen times the length of e m , so that e m being one inch and two thirds , e n was twenty five inches : at n the line n e was crost by a rule of about ½ foot long o p , which from the point n was divided each way into inches and parts , each inch being subdivided into thirty parts , which served to determine , though not precisely , the seconds on the line c d , for a minute of a degree to a thirty six foot glass , being very near one eighth part of an inch , and this eighth part , by the help of the diagonal , being extended to two whole inches upon the three foot rule o p , it became very easie to divide a part of c d , which subtended a minute into sixty parts , and consequently to subdivide it into seconds . now though the sixtieth part of an eighth of an inch be very hardly distinguishable by the naked eye , yet by the help of looking through the eye-glass placed in the cell , and so magnifying the objects at the mensurator more then sixteen times , 't is easie enough to distinguish it . but to proceed , i had one small arm m t in the mensurator , to which the diagonal thred was fastned at the point m , which served for the more nice subdivisions into seconds ; the other diagonal thred which was fastned at u , served for such observations where so great niceness was not so necessary , distinguishing only every four seconds . the points where these diagonal threds were fastned , were exactly over the line a b , and the distances e m and e u were an inch and two thirds , and five inches . there is somewhat of niceness requisite to the fixing these diagonal threads ( which is very material ) at m and u , and that is that there be a small springing slit to pinch the hair fast exactly over the line a b , so that the point of its motion may be precisely in the said east and west line , and not sometimes in it , and sometimes out of it , which it is apt to be , if the diagonal line be fixt in a hole , and move round in it . this was the mensurator by which i measured the exact distance of the stars from our zenith : it may be also made use of for the measuring the diameters of the planets ; for the examining the exact distances of them from any near approaching fixt stars ; for measuring the distances of the satellites of jupiter and saturn from their discks , for taking the diameters and magnitudes of the spots of the moon , and for taking the distances of approaching stars , and for many other mensurations made by telescopes or microscopes , if it be so placed as to be in the focus of the object glass and eye glass . i could here describe at least thirty other sorts , some by the help of screws , others by the help of wedges , some after the way of proportional compasses , others by wheels , others by the way of the leaver , others by the way of pullies , and the like ; any one of which is accurate enough to divide an inch into , , parts if it be necessary ; but i must here omit them , they being more proper in another place , and shall only name one other , because i sometimes made use of it in this observation , which is as simple and plain as this i have described , and altogether as accurate ; but for some accidental circumstances in the place where i made my observation , was not altogether so convenient as the former . this mensurator then is made thus : take a rule of what length it seems most convenient for the present occasion , as two , three , or four foot long , represented by ab in the eighth figure , divide this into , , equal parts , with what accurateness 't is possible , between the points ab . on the top of this rule , at each end fix two cross pieces gh and ef , then from the two cross pieces ef and gh , strain two very fine and even clues , as silkworms clues , curious small hairs , or the like , so as that they cross each other at n , and be distant at o and p , an inch , or any other certain measure desired . let this rule , bezelled on each side , slip in a frame between two cheeks q and r , upon the top of which strein another small hair as st . this frame must be fastned to the telescope , so as st may lye in a due position to the eye glass of it . now in the time of observation the frame qr being fastned to the telescope as above , by sliding the rule ab to and fro , you give upon the line st any length desired , which is noted out by the line st upon the rule ; for if op be put one inch , then xy will be / of an inch , and if op be the subtense of minutes , then xy will be the subtense of ; this is so plain , simple , and easie , that as any ordinary workman will be able to make it , so i doubt not but every reader will , without more application , understand both the description and use thereof . i shall return therefore to the description of the former mensurator . the next thing then is the way of fixing this mensurator , so as to set the threads in their due posture , that is east and west , and north and south , and that they cut each other under the middle of the glass . this last was that which had the most of difficulty in the whole experiment . for the performing of this ▪ i removed the slider underneath the table that carried the eye glass , and also the mensurator , and suffered the plumb lines to hang down through the aperture of the table , and that the balls might come the sooner to their perpendicularity , i suffered them to hang into a vessel of water , deep and wide enough , that they might not touch either side or bottom . this expedient of hanging the plumbets in water i mention , because without it 't is not to be imagined how much time is lost by expectation of the settlement of the said perpendiculars , and how very apt they are to be made to vibrate by the little imperceptible motion of the air , and by any small hair or other impediment how apt to be put out of their perpendicularity : which by the way makes me very fearful that all common instruments have hitherto been lyable to very great errors , by the unaccurate hanging of their plumb lines , being made for the most part to hang and play against the side of the instrument . by this means they would soon come to hang perpendicularly , and be so detained when in that posture ; not being apt to be stirred by the motion of the air , or their own swing ; and whilst thus steady , i fixed two small arms of bras● ▪ such as are described in the seventh figure by z z , z z , which had small holes at the extreams , with a small slit on the side to admit or em●t the plumb line as there was occasion ; one of these is more at large described in the sixth figure . now the plumb line being let into the middle of this , i did with all the accurateness i could so fix the said arm , that the plumb line past exactly through the middle of the hole y. when i was sufficiently satisfied that the plumb line past exactly through the middle of the trying arms , i fixed those arms zz , zz , and removed the plumb lines , then i laid the mensurator l l in the fourth figure , upon the surface of the table , and took great care that the crosses k and l in the seventh figure , lay exactly under the middle of the holes in the arms , which having done by the help of certain screws , i fixt the mensurator fast to the table , and prepared for the observations , putting in the slider gg in the fourth figure , that carried the cell f , and lying down upon a couch ( k of the fourth figure ) made purposely for this observation , i could look directly upward , and with my left ▪ hand move the cell and eye glass so as to find any star which passed within the hole of the table , and at the same time with my right hand i could move the diagonal thread ( rm of the seventh figure ) so as to find exactly how far distant from the zenith e , either northwards or southwards , the stars past the meridian dc , and giving notice to my assistant to prepare , he upon the sign given took notice exactly by a pendulum clock to the parts of a second when the said stars past ▪ and also took notice what division the diagonal thread mr cut upon the rule op . with all these difficulties i was forced to adjust the instrument every observation i made , both before and after it was made , which hath often made me wish that i were near some great and solid tower , or some great rock or deep well , that so i might fix all things at once , and not be troubled continually thus to adjust the parts of the said instrument ; for whoever hath that opportunity will , i question not , especially if the lines of his mensurator be made of the single clues of a silk-worm , with much ease discover plainly a change of the distance of stars of the greater magnitude from the zenith , in a much shorter time then six moneths . this variation also will be much more easie to be discovered , if instead of a thirty six foot glass , there be made use of one of four times that length , to wit , one of one hundred fourty four foot ; and if instead of a tower some deep and dry well be made use of , such as i have seen at a gentlemans house not far from bansted downs in surry , which is dugg through a body of chalk , and is near three hundred and sixty foot deep , and yet dry almost to the very bottom : for such a one is much less subject to any kind of alteration , either from the settling towards this or that side , which most towers and high buildings , whether new or old , are lyable to . this also is safe from bending and shaking with the wind , which i find the strongest houses , towers , and walls , if of any considerable height , are apt to do , nor would the wind have any power to swerve the perpendiculars , which 't is almost impossible to prevent in high buildings above ground . but this i can only wish it were performed , but cannot hope to have any opportunity of doing it my self . but certainly the discovery of the observation will abundantly recompense those that have the curiosity to make it . having thus resolved upon the way , and prepared the instruments fit for the observation , i began to observe the transits of the bright star in the head of draco ; and alwayes both before and after the observation , i adjusted the mensurator by the perpendiculars , that i might be the more certain of the exactness of the instrument ; for i often found that when i came to examine the instrument , a day , or two , or three , or more , after a former observation , that there had been wrought a considerable change in the perpendiculars , in so much as to vary above a minute from the place where i left them , which i ascribe chiefly to the warping of the tube that rose above the roof of the house , finding sensibly that a warm day would bend it considerably towards the south , and that a moist air would make it bend from the quarter of the wind : but yet i am apt to think there might be somewhat also of that variation ascribable to the whole fabrick of the roof , and possibly also to some variation of the floors ; but yet i never found these variations so sudden , as to be perceptible in the time of a single observation , finding alwayes the preceding and subsequent adjustings to answer . the first observation i made was the sixth of july , . when i observed the bright star of draco to pass the meridian northwards of the zenith point of the mensurator , at about two minutes and twelve seconds . the second observation i made was upon the ninth of july following , when i found it to pass to the northwards of the said zenith or cross of the mensurator , near about the same place , not sensibly differing . the third observation i made upon the sixth of august following ; then i observed its transitus north of the aforesaid zenith , to be about two minutes and six seconds . the last observation i made upon the one and twentieth of october following , when i observed it to pass to the north of the zenith , at one minute and about or seconds . inconvenient weather and great indisposition in my health , hindred me from proceeding any further with the observation that time , which hath been no small trouble to me , having an extraordinary desire to have made other observations with much more accurateness then i was able to make these , having since found several inconveniencies in my instruments , which i have now regulated . whether this zenith so found out upon the mensurator , be the true zenith of gresham colledge , is not in this inquiry very material ( though that also i designed to examine , had not an unhappy accident broken my object glass before i could compleat the observation ) for whether it were , or were not , it is certain that it alwayes had the same position to the true zenith , the object glass and perpendiculars having not been in all that time removed out of the cell , whence if the said object glass were thicker upon one side then upon the other ( which is very common and very seldome otherwise ) and consequently deflected the ray towards the thicker side , and so made the perpendicular of the mensurator to lye on that side of the true perpendicular , that the thicker side of the object glass respected , yet it being alwayes so if the transitus of the star varied from this false perpendicular , it must also vary from the true one . the manner how i designed to examine and find out the true perpendicular , is this , which is the way also of adjusting of telescopical sights , as i shall afterwards have occasion to shew . having marked the four sides of the glass , the north with n , the east with e , the south with s , and the west with w , about the first of june i begin to observe and measure the true distance of some remarkable fixt star , as of this of draco from the zenith found one night when the side n of the glass stood north. then i change the side of the object glass , and put the north side southwards , and the south , northwards , and observe the transitus of the same star the next night , and note down the same ; the third night following i put the east side or e north , and observe the transit of the same star over the meridian ; and the fourth night i put the west side or w north , and observe the transit of the said star. now by comparing all these together , it will be very easie to deduce what the false refraction of the object glass is , and which way it lyes , and consequently to regulate the apparent zenith by the true one . but this only by the by . 't is manifest then by the observations of july the sixth and ninth : and that of the one and twentieth of october , that there is a sensible parallax of the earths orb to the fixt star in the head of draco , and consequently a confirmation of the copernican system against the ptolomaick and tichonick . before i leave this discourse , i must not forget to take notice of some things which are very remarkable in the last observation made upon the of october . and those were these . first , that about minutes after three a-clock the same day , the sun being then a good way above the horizon , and shining very clear into the room where i lay to observe , and having nothing to screen off the rayes of light , either in the room where i was , or in the next room through which i looked , i observed the bright star in the dragons head to pass by the zenith as distinctly and clearly as if the sun had been set , though i must confess it had lost much of the glaring brightness and magnitude it was wont to have in the night , and its concomitants were vanisht : the like i found it divers other dayes before , when i observed it , the sun shining very cleer into both the aforesaid rooms , which by the way i suppose was the first time that the fixt stars were seen when the sun shin'd very bright , without any obscuring of its light by eclipse or otherwise . and though we have a great tradition that the stars may be seen with the naked eye out of a very deep well or mine in the day , yet i judge it impossible , and to have been a meer fiction , without any ground : for the being placed at the bottom of a well doth not at all take away the light of the atmosphere from affecting the eye in and near the axis of vision , though indeed the sides thereof may much take off the lateral rayes ; but unless the radiation of the false rayes of the star be brighter then that of the air , the true rayes from the body are so very small , that 't is impossible the naked eye should ever be affected by them . for in the second place , by this observation of the star in the day time when the sun shined , with my foot glass i found the body of the star so very small , that it was but some few thirds in diameter , all the spurious rayes that do beard it in the night being cleerly shaved away , and the naked body thereof left a very small white point . the smalness of this body thus discovered does very fully answer a grand objection alledged by divers of the great anti-copernicans with great vehemency and insulting ; amongst which we may reckon ricciolus and tacquet , who would fain make the apparent diameters of the stars so big , as that the body of the star should contain the great orb many times , which would indeed swell the stars to a magnitude vastly bigger then the sun , thereby hoping to make it seem so improbable , as to be rejected by all parties . but they that shall by this means examine the diameter of the fixt stars , will find them so very small , that according to these distances and parallax they will not much differ in magnitude from the body of the sun , some of them proving bigger , but others proving less ; for the diameter of the parallactical circle among the fixt stars , seems to exceed the diameter of the star almost as much as the diameter of the annual orb of the earth doth that of the sun. and possibly longer and better telescopes will yet much diminish the apparent bulk of the stars by bringing fewer false rayes to the eye that are the occasion of the glaring and magnifying of the said bodies . it may for the present suffice to shew that even with this glass we find the diameter of this star considerably smaller then a second , and the parallax we judge may be about or seconds . it will not therefore be difficult to find many stars whose diameters shall be less then a two hundredth part of this parallax , as possibly upon more accurate observation this very star may be found to be . now we find that the diameter of the orb of the earth is but two hundred times bigger then the diameter of the sun in the center thereof ; and therefore if the parallactical difference be found to be two hundred times more then the visible diameter of the star , the star will prove but of the same magnitude with the sun. this discovery of the possibility and facility of seeing the fixt stars in the day time when the sun shines , as i think it is the first instance that hath been given of this kind , so i judge it will be a discovery of great use for the perfecting astronomy ; as first , for the rectifying the true place of the sun in the ecliptick at any time of the year ; for since by this means 't is easie to find any star of the first , second , or third magnitude at any time of the day , if it be above the horizon , and not too near the body of the sun : and since by a way i shall shortly publish any angle to a semicircle in the heavens , may be taken to the exactness of a second by one single observator : it will not be difficult for future observators to rectifie the apparent place of the sun amongst the fixt stars to a second , or very near , which is one hundred times greater accurateness , then has hitherto been attained by the best astronomers . the like use there may be made of it for observing any notable appulse of the ☽ , ♃ , ♄ , ♂ , and ♀ , to any notable fixt star that shall happen in the day time , which may serve for discovering their true places and parallaxes . the refractions also of the air in the day time may by this means be experimentally detected . i should have here described some clocks and time-keepers of great use , nay absolute necessity in these and many other astronomical observations , but that i reserve them for some attempts that are hereafter to follow , about the various wayes i have tryed , not without good success of improving clocks and watches , and adapting them for various uses , as for accurating astronomy , compleating the tables of the fixt stars to seconds , discovery of longitude , regulating navigation and geography , detecting the proprieties and effects of motions for promoting secret and swift conveyance and correspondence , and many other considerable scrutinies of nature : and shall only for the present hint that i have in some of my foregoing observations discovered some new motions even in the earth it self , which perhaps were not dreamt of before , which i shall hereafter more at large describe , when further tryals have more fully confirmed and compleated these beginings . at which time also i shall explain a system of the world differing in many particulars from any yet known , answering in all things to the common rules of mechanical motions : this depends upon three suppositions . first , that all coelestial bodies whatsoever , have an attraction or gravitating power towards their own centers , whereby they attract not only their own parts , and keep them from flying from them , as we may observe the earth to do , but that they do also attract all the other coelestial bodies that are within the sphere of their activity ; and consequently that not only the sun and moon have an influence upon the body and motion of the earth , and the earth upon them , but that ☿ also ♀ , ♂ , ♄ , and ♃ by their attractive powers , have a considerable influence upon its motion as in the same manner the corresponding attractive power of the earth hath a considerable influence upon every one of their motions also . the second supposition is this , that all bodies whatsoever that are put into a direct and simple motion , will so continue to move forward in a streight line , till they are by some other effectual powers deflected and bent into a motion , describing a circle , ellipsis , or some other more compounded curve line . the third supposition is , that these attractive powers are so much the more powerful in operating , by how much the nearer the body wrought upon is to their own centers . now what these several degrees are i have not yet experimentally verified ; but it is a notion , which if fully prosecuted as it ought to be , will mightily assist the astronomer to reduce all the coelestial motions to a certain rule , which i doubt will never be done true without it . he that understands the nature of the circular pendulum and circular motion , will easily understand the whole ground of this principle , and will know where to find direction in nature for the true stating thereof . this i only hint at present to such as have ability and opportunity of prosecuting this inquiry , and are not wanting of industry for observing and calculating , wishing heartily such may be found , having my self many other things in hand which i would first compleat , and therefore cannot so well attend it . but this i durst promise the undertaker , that he will find all the great motions of the world to be influenced by this principle , and that the true understanding thereof will be the true perfection of astronomy . london , printed for john martyn , printer to the royal society . . physiologia epicuro-gassendo-charltoniana, or, a fabrick of science natural, upon the hypothesis of atoms founded by epicurus repaired [by] petrus gassendus ; 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) physiologia epicuro-gassendo-charltoniana, or, a fabrick of science natural, upon the hypothesis of atoms founded by epicurus repaired [by] petrus gassendus ; augmented [by] walter charleton ... charleton, walter, - . epicurus. gassendi, pierre, - . [ ], , [ ] p. printed by tho. newcomb for thomas heath ..., london : . a second volume on the human soul was planned. cf. conclusion. apparently never published. reproduction of original in university of chicago library. marginal notes. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng science -- history -- early works to . physics -- early works to . atomism. - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - judith siefring sampled and proofread - judith siefring text and markup reviewed and edited - pfs batch review (qc) and xml conversion physiologia epicuro-gassendo-charltoniana : or a fabrick of science natural , upon the hypothesis of atoms , founded by epicvrvs , repaired by petrvs gassendvs , augmented by walter charleton , dr. in medicine , and physician to the late charles , monarch of great - britain . the first part . fernelius , in praefat . ad lib. . de abditis rerum caussis . atomos veteres jam ridemus , miramúrque ut sibi quisquam persuaserit , corpora quaedam solida , atque individua , fortuita illa concursione , res magnitudine immensas , varietate multitudinéque infinitas , omnemque absolutissimum hunc mundi ornatum effecisse . at certè , si democritus mortem cum vita commutare posset , multò acri●● haec , quae putamus elementa , suo more rideret . london , printed by tho : newcomb , for thomas heath , and are to be sold at his shop in russel-street , neer the piazza of covent-garden . . to the honovrable m ris . elizabeth villiers , wife to the honorable robert villiers esquire . madam , the excellent monsieur des cartes , i remember , in his dedicatory epistle of his principles of philosophy , to that illustrious lady , the princess elizabeth ; shewed himself so much a courtier , as to profess unto her highness , that of all persons living , who had perused his former writings , he knew none , that perfectly understood them , except herself only . this , madam , is somewhat more than what i shall adventure to say to you , in this my humble address . not that i might not , with the authority of truth , and the willing testimonies of all judicious persons , whom you have at any time dignified with your incomparable conversation , affirme ; that acuteness of wit , and soundness of iudgement are as eminent in you , as in any that i know , of either sex. but , that i conceive it to be more consistent with my duty of conformity to the strict laws of your humility ( which is supreme among your many virtues , if there can be supremacy where all are superlative ) only to ask you leave , so far to justifie my self , in this way of devotion , as publikely to own my assurance ; that of all my readers , none will meet with fewer difficulties , or discover more lapses and errors , than your self : nor could that book be clearly understood by the author , when he wrote it , which you cannot easily understand , when you are pleased to read it ; be the argument thereof of what kind soever , and the language either italian , french , or english , which are all equally your own . but , i have little reason to speak of justifying this my devotion , to the world ; when that , by the general tribute of admiration and reverence , which your excellencies duely receive from it , is fully convinced , that i am not capable of declaring a greater prudence , in any action of my whole life , than in this of laying down both my self and this mean oblation of my observance and gratitude , at the feet of a personage , whose single name is acknowledged to define all the possible perfections of humanity : and , upon consequence , cannot fail to give to both me and my writings not only an estimation among good men ; but also a full protection from the malevolence of evil. and , i have been very lately told by some ( and those such eminent witts too ; as that very noble persons , to whom they have dedicated their labours , have thereby received no small additions of honour ) that they seriously envied the good fortune of my resolution of invocating your patronage of this epicurean philosophy ; forasmuch as they were confirmed , that i had taken the most certain course , to procure immortality thereunto , by offering it up to the favour of so great an example of all heroick accomplishments , as that her memory must ever continue verdant and sacred to all posterity since it could not be , while generous minds should conserve the memorials of her as the mirrour in which vertue used to dresse herself , when she would appear amiable and graceful ; but that they must often cast some glances of valew upon the remains of him , who had so deep a sentiment of her goodness , as to have known no other ambition , but that commendable one of making himself eternally known for her most humble and obsequious votary . that , which would more become me , were to make my excuses for the exceeding boldness of this my application ; and to pravent such objections as may lye against the rashness of my zeal : in selecting such a way to express my reverence , as cannot secure me from a suspect of prophanation ; and praesenting to you such a sacrifice of my thankfulness , as , if estimated according to its own vnworthiness , must make it a quaestion , whether i had any designe of being thankful at all . and here , to the first , i might justly plead ; that a great part of this volume was composed in your house ( the chief mansion of well-order'd hospitality ) and all of it in the strength of your inspiration . that the book comes not into your hands , to informe , but only remember you of many of those discourses of nature , which your noble husband and your self have often suffered me to entertain ( would to god , i might have said , satisfy ) your eager curiosity withal , at those hours your industrious minds required relaxation from the bent of more grave and advantageous thoughts . that , having the honour of so great a trust , as that of your most praecious lives committed unto me ; it highly concern'd me , to study and pursue all ways of demonstrating my self not altogether uncapable thereof , and more especially this of natural philosophy , which being the grounds , is also the measure of a good physician . and , that when your husband being acquainted with my purpose of enquiring into the nature of souls , both brutal and human , in a distinct work , though but the remaining moity of this physiologie ; had injoyned me to deliver the same into his hands , as soon as i should have finished it : i instantly apprehended , i had an opportunity of a double happiness , the one of being equally grateful to two singular friends ; the other , of allying those two treatises by consecration , which would be of so neer affinity in their subjects . as for the other ; i might easily alleage , that great spirits use not to estimate praesents that are brought them , by the value they carry in themselves : but the affections of those who offer them . that thank fulness is the poor mans wealth , and makes him , in the eyes of generosity , stand in competition , for respect , with the rich. that though this my oblation hold no proportion to the immense height of your merit , yet it is equal to that of my power , and , indeed , the best that my gratitude was able to advance upon the slender stock of my capacity . and , that i never intended it as a retribution f●r your incompensable favours ; but only as an homage , to testifie that i confess my self infinitely your debtor . but , madam , for me to attempt to excuse , unto your self , the vnfitnesse of this act of my devotion ; is no lesse unnecessary , than for me to justifie to the world , that i have placed it upon a most worthy object : forasmuch as i have no more reason to doubt , that so transcendent a charity , as is diffused through and surrounds your perfect soul , can be large enough to dispense with the rudeness of the ceremonies , and poverty of the offering , where you are satisfied of the sincere respects , and unalterable fidelity of his heart , who tenders it ; than i have to fear , that the world should not most readily confirm my judgement , that your deserts have rightfully entitled you to all the demonstrations of honour and reve●ence , that can possibly be given to you . the chief part , therefore , yea the whole of my present duty , is only humbly to beg your benigne acceptance of this dedication , as the best expression i was able to make of those profound sentiments which as well your goodness in general to others , as your particular favours to my self , have impressed upon my soul. and this i now do , upon the knees of my heart ; and solemnly vow , that as i esteem a perfect friend , the greatest treasure of my life , so i do and ever shall account you the most perfect of friends : that i shall confess my self to have lost not only all piety , but all humanity also , when ever i shall willingly lose any the least opportunity of serving you : and that your own good angell ( i speak familiarly , but at the same time believe you to be under the tuition of a legion of good ones ) cannot more fervently desire your complete happiness , than , incomparable madam , your eternal servant , w. charleton . london the of iuly , an. dom. . the contents , series , and order of the whole book . book the first . chap. i. all modern philosophers reduced to four general orders ; and the principal causes of their dissention ▪ pag. . sect . i. artic : the principal sects of the ancient grecian philosophers , only enumerated . pag. the same revived among the moderns , with encrease . who are reduced either to the pedantique or female sect. or , to the assertors of philosophical liberty . or , to the renovators . or to the electors . sect . ii. artic . the principal causes of the diversity of philosophical sects ; and the chiefest among them , the obscurity of nature . the imperfection of our understanding . the irregularity of our curiosity . a paradox . chap. ii. that this world is the vniverse . pag. . sect . i. artic . the ambition of alexander in affecting the conquest , less vain then that of many ancient philosophers in affecting the knowledge of a multitude of worlds . a reduction of those philosophers to four distinct sects ; respective to their distinct perswasions : and the heads of each sect nominated . the two main pillars on which the opinion of a plurality of worlds was anciently erected . sect . ii. the redargution . artic . the question stated to be concerning the real existence , not the possibility of an infinity of worlds . because the supposed infinity of the extramundan spaces , is no impossibility . ibid. because an infinity of bodies is also possible as to the omnipotence of god. ibid. the error of concluding the esse , from the posse of an infinity of worlds . the first main pillar of a plurality of world● subverted ibid. the second pillar found sophisticate , and demolished . a plurality of worlds manifestly repugnant to authority divine and human. ibid. the result of all ; the demonstration of the authors thesis , that this world is the universe . ibid. extramundane curiosity , a high degree of madness . chap. iii. corporiety and ●nanity , p. sect . i. artic . body and inanity , the two general parts of the vniverse . three the most memorable definitions of corporiety extant among physiologists , recounted and examined . ibid. four descriptions of the nature of inanity , by epicurus , cleomedes , empericus , aristotle . their importance extracted : and what is the formal or proper notion of a vacuum . the existence of bodies in the world , manifest by sense : whose evidence is perfect demonstration . ibid. chap. iv. a vacuum in nature . p . sect . i. art . the distinction of a 〈◊〉 into ( ● ) natural , and ( ) praeternatural ▪ and the one called disseminate , the other co●cervate . the nature of a dissemi●●te va●uity , explained by the analogy of a heap of corn. ibid. the first argument of a disseminate vacuity , desumed from the evidence of motion , in general : and aristotles error concerning the essence or place , concisely detected , and corrected . motion demonstrated by sense : and zeno's aenigmatical argument ▪ for an vniversal quiet , dissolved . the consequution of the argument ( if no vacuum , no motion ) illustrated . an objection , that the ●ococession of some bodies , depends on their ●arity or porosity ; not on a disseminate vacui●● : praevented . ibid. no beginning of motion , without inanity inter●●ersed . sect . ii. art●c . a second argument of a vacuity disseminate , collected from the reason of rarefaction and condensation . ibid. the eminent phaenomenon ●f an aerosclopet , or wind gun , solved by a vacuity disseminate among the incontiguous ( quoad totas superficies ) parts of aer . experiment of an aeolipile , or hermetical bellows , attesting a vacuity disseminate . ibid. experiment of a sulphurate tapor , included in a glass vial , partly 〈◊〉 with water : of the same importance . no combustible in aer : and so the opinion of the aristoteleans , that the extinction of f●ame imprisoned , is to be charged on the de●ect of aer for its sustentation ; grosly err●neous . a fourth singular and memorable experiment of the authors , of y●e at the nose of a large reverberatory furnace , charged with ignis rotae ; evidencing a vacuity interspersed in the aer . an inference from that experiment ; that aer as to its general destination , is the common receptary of exhalations . ibid. a second illation , that the aer doth receive exhalations at a certain rate , or definite proportion ; which cannot be transcended without prodigious violence . the existence of inane incontiguities in the aer , confirmed by two considerable arguments . ibid sect . iii. artic . that water also contains vacuola empty spaces ; demonstrated . from the experiment of the dissolution of alum , halinitre sal ammoniac , and sugar , in water formerly sated with the tincture of common salt. ibid. the verity of the lord bacons assertion , that a repeated infusion of rhubarb acquires as strong a virtue cathar●●ical as a simple infusion of scamony , in equal quantity : and why why two drachms of antimony impraegnate a pint of wine with so strong a vomitory faculty as two ounces . ibid. why one and the same menstruum may be enriched with various tinctures . ibid. sect . iv. artic . two other arguments of a vacuity disseminate inferrible from ( ) the difference of bodies in the degrees of gravity : ( ) the calefaction of bodies by the penetration of igneous atoms into them . the experiments vulgarly adduced to prove no vacuity in nature , so far from denying , that they confess a disseminate one . ibid. the grand difficulty of the cause of the aers restitution of it self to its natural contexture , after rarefaction and condensation , satisfyed in brief . ibid. chap. v. a vacuum praeternatural . p. . sect . i. artic . what is conceived by a coacervate vacuity : and who was the inventer of the famous experiment of quick-silver in a glass tube , upon which many modern physiologists have erected their perswasion of the possibility of introducing it . a faithful description of the experiment , and all its rare phaenomena . the authors reason , for his selection of onely six of the most considerable phaenomena to explore the causes of them . sect . ii. artic . the first cardinal difficulty . the desert space in the tube argued to be an absolute vacuum coacervate , from the impossibility of its repl●tion with aer . ibid. the experiment praesented in iconism the vacuity in the desert space , not praevented by the insinuation of aether . a paradox , that nature doth not abhor all vacuity , per se ; but onely ex accidenti , or in respect to fluxility . ibid. a second argument against the repletion of the desert space by aether . the vacuity of the desert space , not praevented by an halitus , or spiritual e●●lux from the mercury : for three convincing reasons . the authors apostacy from the opinion of an absolute coacervate vacuity in the desert space : in regard of ibid. the possibility of the subingression of light . ibid. of the atoms or insensible bodies of heat and cold : which are much more exile and penetrative then common aer . of the magnetical e●●lux of the earth : to which opinion the author resigns his assent . no absolute plenitude , nor absolute vacuity , in the desert space : but onely a disseminate vacuity . ibid. sect . iii. artic . the second difficulty stated . two things necessary to the creation of an excessive , or praeternatural vacuity . ibid. the occasion of galilaeos invention of a brass cylindre charged with a wooden embol , or sucker : and of torricellius invention of the praesent experiment . ibid. the marrow of the difficulty , viz. how the aer can be impelled upward , by the restagnant quick silver , when there externally wants a fit space for it to ci●culate into . the solution of the same , by the laxity of the contexture of the aer . ibid. the same illustrated , by the adaequate simile of corn infused into a bushel . ibid. a subordinate scruple , why most bodies are moved through the aer ▪ with so little resistence , as is imperceptible by sense ? the same expeded . ibid. a second dependent scruple concerning the cause of the sensible resistence of the aer , in this case of the experiment : together with the satisfaction thereof , by the gravity of aer . ibid. sect . iv. artic . the state of the third difficulty . the solution thereof in a word . ibid. three praecedent positions briefly recognized , in order to the worthy profounding of the mystery , of the aers resisting compression beyond a certain rate , or determinate proportion ibid. the aequiponderancy of the external aer , pendent upon the surface of the restagnant mercury , in the vessel to the cylindre of mercury residuous in the tube , at the altitude of digits : the cause of the mercuries constant subsistence at that point . a convenient simile , illustrating and enforcing the same . the remainder of the difficulty ; viz. why the aequilibrium of these two opposite weights , the mercury and the aer , is constant to the praecise altitude of digits : removed . ibid. humane perspicacity terminated in the exterior parts of nature , or simple apparitions : which eluding our cognition , frequently fall under no other comprehension , but that of rational conjecture . ibid. the constant subsistence of the mercury at digits , adscriptive rather to the resistence of the aer , then to any occult quality in the mercury . the analogy betwixt the absolute and respective aequality of weights , of quick-silver and water , in the different altitudes of digits and feet . the definite weights of the mercury at digits , and water at feet , in a tube of the third part of a digit in diametre ; found to be neer upon two pound , paris weight . ibid. quaere , why the aequilibrium is constant to the same point of altitude in a tube of a large concave , as well as in one of a small ; when the force of the depriment must be greater in the one , then the other . the solution thereof by the appropriation of the same cause , which makes the descent of two bodies , of different weights , aequivelox . ibid. sect . v. artic . the fourth capital difficulty proposed . the full solution thereof , by demonstration . ibid. the same confirmed by the theory of the cause of the mercuries frequent reciprocations , before it acquiesce at the point of aequipondium . ibid. sect . vi. artic . the fifth principal difficulty . solved , by the motion of restauration natural to each ins●nsible particle of aer . ibid. the incumbent aer , in this case , equally distressed , by two contrary forces . the motion of restauration in the aer●extended to the satisfaction of another consimilar doubt , concerning the subintrusion of water into the tube ; if superaffused upon the restagnant mercury . ibid. a third most important doubt , concerning the nonapparence of any tensity , or rigidity in the region of aer incumbent upon the restagnant liquors . ibid. the solution thereof , by the necessary reliction of a space in the vic●●● region of lax aer , equal to that , which the hand commoved possesseth in the region of the comprest . a confirmation of the same reason , by the adaequate example of the flame of a tapour . ibid. by the experiment of urination . ibid. by the beams of th● sun , entring a room , through some slender crany , in the appearance of a white shining wand , and constantly maintaining that figure , notwithstanding the agitation of the aer by wind , &c. by the constancy of the rainbow , to its figure , notwithstanding the change of position and place of the cloud and contiguous aer . ibid. helmonts d●lirium , that the rainbow is a supernatural meteor : observed . ibid. sect . vii . artic . the sixth and last considerable difficulty . ibid. the cleer solution there●● , by the great disproportion of weight betwi●t quick-silver and water . a corollary ; the altitude of the atmosphere conjectured . ibid. a second corollary ; the desperate difficulty of conciliating physiology to the mathematicks : instanced in the much discrepant opinions of galilaeo and mersennus , concerning the proportion of gravity that aer and water hold each to other . ibid. the conclusion of the digression : and the reasons , why the author●●●cribes ●●●cribes a cylindrical figure to the portion of aer impendent on the restagnant liquors , in the experiment . chap. vi. of place . p. . sect . i. artic . the identity essential of a vacuum and place , the cause of the praesent enquiry into the nature of place . ibid. among all the quaeries about the hoti of place ; the most important is , whethor epicurus or aristotles definition of it , be most adaequate . ibid. the hypothesis of aristotles definition a convenient supposition inferring the necessity of dimentions incorporeal . ibid. the legality of that supposition . ibid. the dimensions of longitude , latitude , and profundity , imaginable in a vacuum . the grand peripatetick objection , that nothing is in a vacuum ; ergo no dimensions . ibid. des chartes , and mr. white seduced by the plausibility of the same . the peripateticks reduction of time and place to the general categories of substances and accidents , the cause of this epidemick mistake . ibid. place neither accident nor substance . the praecedent giant - objection , that nothing is in a vacuum ; stab'd , at a blow . ibid dimensions corporeal and incorporeal , or spatial . the former supposition reassumed and enlarged . ibid. the scope and advantage thereof ; viz. the comprehension of three eminent abstrusities concerning the nature of place . ibid. the incorporiety of dimentions spatial , discriminated from that of the divine essence , and other substances incorporeal . this persuasion , of the improduction and independency of place ; praeserved from the suspition of impiety . ibid. sect . ii. artic . place , not the immediate superfice of the body invironing the locatum ; contrary to aristotle . salvo's for all the difficult scruples , touching the nature of place ; genuinely extracted from epicurus his 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . ibid aristotles ultimate refuge . the invalidity thereof : and the coexistibility , or compatibility of dimensions corporeal and spatial . chap. vii . of time and eterntiy . p. . sect . i. artic . the hoti of time more easily conceivable by the simple notion of the vulgar , then by the complex definitions of philosophers . ibid. the general praesumption that time is corporeal , or an accident dependent on corporeal subjects ; the chief cause of that difficulty . the variety of opinions , concerning it ; another cause of the difficulty : and epicurus description of its essence , recited and explained . ibid. time defined to be coelestial motion , by zeno , chrysippus , &c. and thereupon affirmed , by philo , to be onely coaevous to the world. aristotles so much magnifyed definition of time to be the measure of motion coelestial , &c. perpended and found too light . ibid. sect . ii. artic ▪ time , nor substance , nor accident : but an ens more general , and the twin-brother of space . ibid. a paralellism betwixt space and time. ibid. time , senior unto , and independent upon motion : and onely accidentally indicated by motion , as the mensuratum by the mensura . a demonstration of the independence of time upon motion , from the miraculous detention of the sun , above the horison , in the days of joshua . an objection , that , during the arrest of the sun , there was no time , because no hours ; satisfyed . ibid. the immutability of time also asserted against aristotle . ibid. sect . iii. artic . the grand question , concerning the disparity of time and aeternity : stated . two praeparatory considerations , touchant the aequivocal use of the word aeternity : requisite to the cleer solution thereof . ibid two decisive positions , thereupon inferred and established . the platonicks definition of eternity , to be one everlasting now ; not intelligible , and therefore collusive . their assertors subterfuge , that eternity is coexistent to time ; also unintelligible . ibid. our ecclesiastick doctors , taking sanctuary in the . exod. for the authorizing of their doctrine , that the present tense is onely competent to god , and so that eternity is one permanent instant , without fusion or succession : not secure from the rigour of our demonstration . the objective praesence of all things at once , to the divine intellect ; no ways impugned by our contradiction of the doctors theory . ibid nor the immutability of the divine nature , against aristotle . coronis . the second book . chap. i. the existence of atoms , evicted . p. . sect . i. artic : the right of the authors transition from the incorporeal to the corporeal part of nature : and a series of his subsequent speculations : ibid. bodies generally distinshed into principles and productions , with their scholastick denomiminations and proprieties . the right of atoms to the attributes of the first matter . ibid. their sundry appellations allusive to their three eminent proprieties . ibid. two vulgarly passant derivations of the word , atom , exploded . who their inventor : and who their nomenclator . their existence demonstrated . that nature , in her dissolution of concretions , doth descend to the insensible particles . that she can run on to infinity . ibid. but must consist in atoms , the term of exsolubility . ibid. a second argument of their existence , drawn from that of their antitheton inanity . a third , hinted from the impossibility of the production of hard bodies , from any other principle . ibid. a fourth , from the constancy of nature in the specification and determinate periods of her generations . ibid. chap. ii. no physical continuum , infinitely divisible . p. . sect . i. artic . the cognation of this theorem , to the argument of the immediately praecedent chapter . ibid ▪ magnitude divisible by a continued progress through parts either proportional , or aliquotal . ibid. the use of that distinction in the praesent . ● the verity of the thesis , demonstrated . ibid. two detestable absurdities , inseparable from the position of infinite parts in a continuum . ibid. aristotles subterfuge of infinitude potential ; found openly collusive . a second subterfuge of the stoick ; ibid. manifestly dissentaneous to reason . ibid sect . ii. artic . the absurdities , by empericus , charged upon the supposition of only finite parts in a continuum . the sundry incongruities and inconsistences , by the modern anti-democritans , imputed to the supposition of insectility . ibid. the full derogation of them all together , by one single responce ; that the minimum of atomists is not mathematical , but physical , contrary to their praesumption . a seeming dilemma of the adversary , expeditely evaded . a digression , stating and determining that notable quaestion , whether geometrical demonstrations may be conveniently transferred to the physical or sensible quantity ? ibid. chap. iii. atoms , the first and vniversal matter . p . sect . i. art . the introduction , hinting the two general assumptions of the chapter . ibid. democritus and epicurus vindicated from the absurd admission of inanity to be one principle of generables . ibid. atoms not inconsistent with , because the principles of the four vulgar elements . the dissent of the ancients , about the number of elements . no one of the four elements sufficient to the production of either any of the other three , or of any compound nature ibid. the four elements , not the protoprinciple of concretions . atoms discriminated from the homoiomerical principles of anaxagoras . ibid. the principal difficulties urged against the hypothesis of atoms , singularly solved . a recapitulation of the praemises , introductory to the verification of the praesent thesis : sect . ii. artic . the notable opinions , concerning the composition of a continuum . a physical continuum cannot consist of points mathematical . ibid. nor of parts and points mathematical , united . nor of a simple entity , before division indistinct : but of indivis●bles . ibid. a second apodictical reason , desumed from the nature of vnion , evi●cing that atoms are the first and catholick principle of concretions . an objection praevented . ibid. the reason of the authors supercession of all other arguments of the like importance . ibid. chap. iv. the essential proprieties of atoms : p. . sect . i. artic . the two links connecting this to the praecedent chapter . ibid. the general proprieties of atoms : and the inseparability of each , demonstrated . ibid. the resistence of atoms , no distinct propriety ; but pertinent to their solidity or gravity ▪ the specifical proprieties of atoms . ibid. sect . ii. concerning the magnitude of atoms . p. . artic . by the magnitude , is meant the parvity of atoms . ibid. a consideration of the grossness of our senses , and the extreme subtilty of nature in her operations ; praeparatory to our conjectural apprehension of the exiguity of her materials , atoms . ibid. the incomprehensible subtility of nature , argued from the artifice of an exquisite watch , contrived in a very narrow room . the vast multitude of sensible particles , and the vaster of elemental atoms , contained in one grain of frankinsense ; exactly calculated . ibid. the dioptrical speculation of a handworm , discovering the great variety of organical parts therein , and the innumerability of their component particles . a short digressive descant upon the text of pliny , touching the multiplicity of parts in a flea ; hinting the possible perspicacity of reason . ibid. the exility of atoms , conjectural from the great diffusion of one grain of vermillion dissolved in water . the same , inferrible from the small quantity of oil depraedated by the flame of a lamp , in a quarter of an hour . ibid. the microscope of great use , in the discernment of the minute particles of bodies : and so advantageous to our conjecture , of the exility of atoms . ibid sect . iii. concerning the figures of atoms . p. . artic . an epitome of all that directly concerns the fig●res of atom● in three general canons . ibid. the first canon explained and certifyed . ibid. the exility of atoms , do●h not necessitate their general roundness 〈◊〉 contrary to the common conceit . ibid. the diversity of figures in atoms , evicted from the sensible dissimilitude of individuals , as well animate as inanimate . a singular experiment , antoptically demonstrating the various configurations of the minute particles of concretions . a variety of figures in atoms , necessary to the variety of all sensibles . ibid. the second canon , explained and certified . the third canon , explained , and refuted . sect . iv. concerning the motions of atoms . p. . artic . two introductory observables . ibid. the motion of atoms , according to the general distinction of the ancients , two-fold ; viz natural , and accidental : and each of these redivided into two different species . ibid. the summary of epicurus figment , of the perpendicular motion of atoms , without a common centre . his declinatory natural motion of atoms , excused ; not justified . ibid. the genuine sense of epicurus , in his distinction of the reflex motion of atoms into ex plaga , and ex concussione . the several conceptions of epicurus , about the perpetual motions of atoms . the perpetual inquietude of atoms , even in compact concretions , adumbrated in melted lead . ibid. the same more sensibly exemplified , in the spirit extracted from mercury , tin , and subsimate . the mutability of all concretions , a good argument of the perpetual intestine commotion of atoms , in the most adamantine compositions . ibid. what we are to explode , and what retain , in the opinion of epicurus , touching the motion of atoms . ibid. the third book . chap. i. the origine of qualities . p. : sect . i. artic . an introductory advertisement● ; of the obscurity of many thing to reason which are manifest to sense : and of the possibility , not necessity of the elementation of concretions , and their sensible qualities , from the principles praesumed . the authors definition of a quality , in geral : and genuine exposition of democritus mysterious text , concerning the creation of qualities . the necessary deduction of qualities from naked or unqualified principles . the two primary events of atoms , viz. order and position , associated to their three essential proprieties , viz. magnitude , figure , and motion ; sufficient to the origination of all qualities . ibid. the necessity of assuming the magnitude and motion of atoms , together with their order and situation , as to their production of qualities , evicted by a double instance . the figure , order and position of parts in concretions , alone sufficient to the caussation of an indefinite variety of qualities , from the analogy of letters . ibid. the same exemplifyed in the arise of white froth , on the waves of the sea. the nativity of colours in general , explained by several obvious examples . ibid. the accention of heat , from concretions actually cold , upon a meer ttransposition of their component particles ; exemplifyed in sundry chymical experiments . the generation of all kinds of sensible qualities in one and the same con●retion , from the variegated positions of its particles : evidenced in the example of a putrid apple . the assenting suffrage of epicurus . ibid. chap. ii. that species visible are substantial emanations . p. . sect . i. artic : the visible images of objects , substantial : and either corporeal emanations from the superficial parts of concretions ; or light it self , disposed into contextures , consimilar to the figure of the object . ibid , the position of their being effluviaes , derived from epicurus ; and praeferred to the common doctrine of the schools of the immateriality of species visible . ibid. epicurus text concerning the same . the faithful exposition thereof . ibid. the contents thereof reduced to four heads . the existence of images visible , certifyed by autoptical demonstration . ibid ▪ epicurus opinion , of the substantiality of images visible , consonant to the judgement of plato and empedocles . the aristoteleans thesis , that images optical are meer accidents , recited : and ibid. convicted of sundry impossibilities , inconsistences , and absurdities . ibid. the grand objection of alexander , that a con tinual efflux of substance must minorate the quantity ●f the most solid visible . solved by two reasons ; the possible accretion of other particles ; and the extreme tenuity of the emanent . the tenuity of images visible , reduced to some degree of comprehensibility , by conceiving them to be most thin decortications . ibid. by instance , in the visible species of the foot of a handworm . ibid. by exemplifying in the numerous round films of wax , successively derepted from a wax tapor by the flame thereof , in the space of an hour ▪ and in the innumerable films of oyl , likewise successively delibrated , by the flame of an ellychnium , or match , perpendicularly floating in a vessel of equal capacity with solomons brazen sea , in the space of hours . ibid. by the analogy betwixt an odorable and visible species . ibid. the manner and reason of the production of visible images ; according to the hypothesis of epicurus . the celerity of the motion of visible images , reasoned ; and compared to that of the light of the sun. the translation of a moveable from place to place , in an indivisible point of time , impossible : and why ? ibid. the facility of the abduction , or avolation of images visible , from solid concretions ; solved by the spontaneous exsilition of their superficial atoms : and the sollicitation of light incident upon them . ibid. that objects do not emit their visible images ; but when illustrated : a conceit though paradoxical , yet not improbable . sect . ii. artic . visible images systatical , described ; and distinguisht from apostatical ones . their existence assured , by the testimony of diodorus siculus : and ibid. damascius , together with the autopsy of kircher . ibid. kirchers description of that famous apparition at rhegium , called morgana rheginorum : and most ingenious investigation of the causes thereof . ibid. his admirable artifice , for the exhibition of the like aereal representation , in imitation of nature . chap. iii. concerning the manner and reason of vision . p. . sect . i. artic . the reason of vision , according to the opinion of the stoicks . of aristotle . of the pythagoreans . ibid. of empedocles . ibid. of plato . ibid. of epicurus . ibid. of mons. des chartes . the ingenuity of des chartes conceit , acknowledged : but the solidity indubitated . the opinion of epicurus more satisfactory , then any other : because more rational , and less obnoxious to inexplicable difficulties . ibid. the two most considerable difficulties opposed to epicurus position , of the incursion of substantial images into the eye . sect . ii. artic . that the superfice of no body is perfectly smooth : evicted by solid reason , and autopsie . ibid. that the visible image doth consist of so many rays as there are points designable in the whole superfice of the object : and that each ray hath its line of tendency direct , respective to the face of that particle in the superfice , from which it is emitted . that the density and union of the rays , composing the visible image , is greater or less ; according to their less , or greater elongation from the object . ibid. that the visible image is neither total in the total medium ; nor total in every part thereof : but so manifold as are the parts of the medium from which the object is discernable . contrary to the aristoteleans . paradox . that no man can see the same particle of an object , with both eys at once ; nay , not with the same eye , if the level of its visive axe be changed . ibid. consectary . that the medium is not possessed with one simple image ; but by an aggregate of innumerable images , deradiate from the same object : all which notwithstanding constitute but one entire image . consectary . . that myriads of different images , emanant from different objects , may be coexistent in the aer ; without reciprocal penetration of dimensions , or confusion of particles : contrary to the peripateticks . ibid that the place of the visible images ultimate reception , and complete perception ; is the concave of the retina tunica . that the faculty forms a judgement of the conditions of the object , according to the representation thereof by the image , at its impression on the principal part of vision , the amphiblestroides . ibid. consectary . that the image is the cause of the objects apparence of this or that determinate magnitude . consectary . that no image can replenish the concave of the retina tunica , unless it be deradiated from an object of an almost hemispherical ambite . why , when the eye is open there is alwayes pourtrayed in the bottom thereof , some one total image ; whose various parts , are the special images of the several things included in the visual hemisphere . ibid. paradox . that the prospect of a shilling , or object of a small diametre is as great , as the prospect of the firmament . why an object appears both greater in dimensions and more distinct in parts , neer at hand , than far off . ibid. why an object , speculated through a convex lens , appears both greater and more distinct ; but through a concave , less and more confused : than when speculated only with the eye . digression . what figur'd perspicils are convenient for old : and what for purblind persons . that to the dijudication of one of two objects , apparently equal , to be really the greater ; is not required a greater image : but only an opinion of its greater distance . des cartes opinion concerning the reason of the sights apprehending the distance of an object : vnsatisfactory ; and that for two considerations . ibid. and that more solidone of gassendus ( viz. that the cause of our apprehending the distance of an object , consisteth in the comparation of the several things interjacent betwixt the object and the eye , by the rational faculty ) embraced and corroborated . ibid. paradox . that the same object , speculated by the same man , at the same distance , and in the same degree of light ; doth alwayes appear greater to one eye , than the other . a second paradox . that all men see ( distinctly ) but with one eye at once : contrary to that eminent optical axiom , that the visive axes of both ey● concur , and unite in the object . the three degrees of vision , viz. most perfect , perfect , and imperfect : and the verity of the paradox restrained onely to the two former degrees . sect . iii. artic . a research into the reason of the different effects of convex and concave glasses ; as well dioptrical , as catoptrical . ibid. a corollarie . hinting the causes , why an elliptical concave reflects the incident rays , in a more acute angle , than a parabolical : and a parabolical than a spherical . a consectary . why a plane perspicil exhibits an object in genuine dimensions ; but a convex , in amplified , and a concave in minorated . sect . iv. artic . a recapitulation of the principal arguments precedent : and summary of the subsequent . the eye anatomized : and the proper use of each part thereof , either absolutely necessary , or onely advantagious to vision concisely demonstrated . viz. the diaphanity of the horny membrane , and the three humors , aqueous , chrystalline , and vitreous . the convexity of all its parts except the amphiblestroides . the uvea tunica , and iris. ▪ the pupilla . the blackness of the inside of the uvea tunica . the tunica arachnoides . the ciliary filaments thereof . the chrystalline . the retina tunica . the six muscles , viz. the direct , as the atollent , depriment , adducent , abducent . and oblique , as the circumactors , or lovers muscles . , to why the situation of an object is perceived by the sight . the reason of the eversion of the image , in the amphiblestroides . the same illustrate by an experiment . ibid. why the motion and quiet of objects are discerned by the sight . ibid. why catoptrical images imitate the motions of their antitipes or originals . ibid. why the right side of a catoptrical image respects the left of its exemplar . and why two catoptrick glasses , confrontingly posited , cause a restitution of the parts of the image to the natural form. chap. iv. the nature of colours . p. . sect . i. artic . the argument duly acknowledged to be superlatively difficult , if not absolutely acataleptical . ibid. the sentence of aristotle concerning the nature of colours : and the commentary of scaliger thereupon . the opinion of plato . ibid. of the pythagorean and stoick . of the spagyrical philosophers . ibid. the reason of the authors desertion of all these ; and election of democritus and epicurus judgement , touching the generation of colours . ibid. the text of epicurus , fully and faithfully expounded . sect . ii. artic . a paradox . that there are no colours in the dark . a familiar experiment , attesting the verity thereof . ibid. the constancy of all artificial tinctures , dependent on the constancy of disposition in the superficial particles of the bodies that wear them . that so generally magnified distinction of colours into inhaerent , and meerly apparent ; redargued of manifest contradiction . ibid. the emphatical , or evanid colours , created by prisms ; no less real and inhaerent , than the most durable tinctures . corollary . the reasons of emphatical colours , appinged on bodies objected , by a prism . the true difference of emphatical and durable colours , briefly stated . ibid. no colour formally inhaerent in objects ; but only materially , or effectively : contrary to the constant tenent of the schools . ibid the same farther vindicated from difficulty , by the tempestive recognition of some praecedent assumptions of the atomists . sect . iii. artic . the nativity of white ; or the reason of its perception by the sight . black , a meer privation of light. ibid. the genealogy of all intermediate colors . ibid. the causes of the sympathy and antipathy of some colours the intermis●ion of small shadows , among the lines of light ; absolutely necessary to the generation of any intermediate colour . ibid. two eminent problems concerning the generation and transposition of the vermillion and caerule , appinged on bodies by prismes . the solution of the former : with a rational conjecture of the cause of the blew , apparent in the concave of the heavens . the solution of the latter . the reasons , why the author proceeds not to investigate the causes of compound colours in particular . he confesseth the erection of this whole discourse , on simple conjecture : and enumerates the difficulties to be subdued by him , who hopes to attain an apodictical knowledge of the essence and causes of colours . ibid. des cartes attempt to dissolve the chief of those difficulties ; unsuccessful : because grounded on an unstable hypothesis . chap. v. the nature of light. p. . sect . i. artic . the clasp , or ligament of this , to the praecedent chapter . ibid. the authors notion of the rays of light. ibid. a parallelism betwixt a stream of water exsilient from the cock of a cistern , and a ray of light emanent from its lucid fountain . ibid ▪ praeconsiderables . light distinguisht into primary , secondary , &c. all light debilitated by reflection : and why . ibid. an example , sensibly demomonstrating the same . that light is in perpetual motion ; according to aristotle . ibid. light , why corroborated , in some cases , and debilitated in others , by refraction . corollary . why the figure of the sun , both rising and setting , appears rather elliptical , than sphaerical . ibid. paradox . that the proportion of solary rays reflected by the superior aer , or aether , toward the earth , is so small , as not to be sensible . that every lucid body , as lucid , doth emit its rays sphaerically : but , as visible ; pyramidally . ibid. that light is invisible in the pure medium . sect . ii. artic . the necessity of the authors confirmation of the first praeconsiderable . the corporiety of light , demonstrated by its just attributes : viz. locomotion . resilition . refraction . coition . disgregation . igniety . , aristotles definition of light , a meer ambage , and incomprehensible . thecorporiety of light imports not the coexistence of two bodies in one place ; contrary to the peripatetick . nor the motion of a body to be instantaneous . ibid. the invisibility of light in the limpid medium , no argument of its immateriality : as the peripatetick praesumes ibid. the corporiety of light fully consistent with the duration of the sun : contrary to the peripatetick . the insensibility of heat in many lucent bodies , no valid argument against the praesent thesis , that light is flame attenuated . ibid. chap. vi. the nature of a sound . p . sect . i. artic . an elogy of the sense of hearing : and the relation of this and the praecedent chapter . ibid. the great affinity betwixt visible and audible species ; in their representation of the superficial conditions of objects . in the causes and manner of their destruction . ibid. in their actinobolism , or diffusion , both sphaerical and pyramidal . in their certifying the sense of the magnitude , figure , and other qualities of their originals . ibid. in the obscuration of less by greater . in their offence of the organs , when excessive . ibid. in their production of heat by multiplication . ibid. in their variability , according to the various disposition of the medium . ibid. in their chief attributes , of locomotion , exsilition , impaction , resilition , disgregation , congregation . ibid. sect . ii. artic . the product of the praemises , concerning the points of cons●nt , and dissent of audible and visible species : viz that sounds are corporeal . an obstruction of praejudice , from the generally supposed repugnant authorities of some of the ancients ; expeded . ibid. an argument of the corporiety of sounds . a second argument . ibid. corollary . ibid. the causes of concurrent echoes , where the audient is equally ( almost ) distant from the sonant and repercutient . ibid. corollary . . why concaves yield the strongest and longest sounds . ibid. corollary . . ibid the reason of concurrent echoes , where the audient is neer the 〈◊〉 , and remote from the sonant . ibid. corollary . . ibid. w●y 〈◊〉 monophon rehearse so much the f●●er syllables , by how much neerer the audient is to the r●f●●ctent . ibid. corollary . ibid. the reason of polyphon echoes . ibid. a third argument of the materiality of sounds : the necessity of a certain configuration in a sound ; inferred from the distinction of one sound from another , by the sense . ibid. the same confirmed by the authority of pythagoras , plato , and aristotle . ibid. and by the capacity of the most subtle parts of the aer the reason and manner of the diffusion of sounds , explicated by a congruous simile . ibid. the most subtle particles of the aer onely , the material of sounds . paradox . ibid. one and the same numerical voice , not heard by two men , nor both ears of one man. ibid. a problem not yet solved by any philosopher : viz. how such infinite variety of words is formed only by the various motions of the tongue and lips. a second ( also yet unconquered ) difficulty , viz. the determinate pernicity of the aers motion , when exploded from the lungs , in speech . ibid. all sounds created by motion , and that either when that intermediate aer is confracted by two solids mutually resistent ; or when the aer is percust by one solid ; or when a solid is percust by the aer . ibid. rapidity of motion necessary to the creation of a sound , not in the first case . but , in the second and last . ibid. that all sounds are of equal velocity in the delation . ibid. the reason thereof . ibid. to measure the velocity of great sounds . sounds , not subject to retardation from adverse ; nor acceleration , from secund winds . ibid. sect . iii. artic . that all sounds , where the aer is percussed by one solid , are created immediately by the frequency , not the velocity of motion ; demonstrated . and likewise , where the aer is the percutient . ibid. that all acute sounds arise from the more , and grave from the less frequent percussions of the aer , demonstrated . the suavity of musical consonances , deduced from the more frequent ; and insuavity of dissonances from the less frequent vnion of the vibrations of strings , in their terms . the same analytically pr●sented in scheme . a just and unanswerable exception against the former harmonical hypothesis . ibid. problem . in what instant , an harmonical sound , resulting from a chord percussed , is begun . that a sound may be created in a vacuum ; contrary to athanas. kircher in art. magn. consoni & dissoni lib. . cap. , digres . why all sounds appear more acute , at large , than at small distance . why cold water falling , makes a fuller noise , than warm . ibid. why the voice of a calf is more base than than that of an ox , &c. why a dissonance in a base is more deprehensible by the ●ar , than in a treble voice . ibid. chap. vii . of odours . p. . sect . i. artic . that the cognition of the nature of odours is very difficult ; in respect of the imperfection of the sense of smelling , in man : and ibid. the contrary opinions of philosophers , concerning it . some determining an odour to be a substance . ibid. others a meer accident or quality . the basis of the latter opinion , infirm and ruinous . that all odor●us bodies ●mit corporeal exhalations . ibid. that odours cause sundry affections in our bodies , such as are consignable onely to substances . ibid. that the reason of an odour's affecting the sensory , consists only in a certain symbolism be-the figures and contexture of its particles , and the figures and contexture of the particles of the odoratory nerves . that the diversity of odours depends on the diversity of impressions made on the sensory , respondent to the various figures and contexture of their particles . why some persons abhor those smells , which are grateful to most others . ibid. why , among beasts , some species are offended at those scents in which others highly delight . the generation and diffusion of odours , due onely to heat . ibid. the differences of odours . the medium of od●urs . chap. viii . of sapours . p. . sect . i. artic . from the superlative acuteness of the sense of tasting , aristotle concludes the cognition of the nature of sapours to be more easily acquirable , than the nature of any other sensible object ▪ but refutes himself by the many errors of his own theory , concerning the same . ibid. an abridgment of his doctrine , concerning the essence and causes of a sapour , in general . and the differences of sapour , with the particular causes of each . ibid. an examination and brief redargution of the same doctrine . the post position thereof to the more verisimilous determination of the sons of hermes , who adscribe all sapours to salt. ibid. but far more to that most profound and satisfactory tenent of democritus and plato ; which deduceth the nativity of sapours from the various figures and contextures of the minute particles of concretions . ibid. the advantages of this sentence , above all others touching the same subject . the objections of aristotle concisely , though solidly solved . ● that the salivous humidity of the tongue s●rveth to the dissolution and imbibition of salt in all gustables . chap. ix . of rarity , density , perspicuity , opacity . p. . sect . i. art . this chapters right of succession to the former . ibid. the divers acceptation of the term , touching ▪ ibid. a pertinent ( though shortt ) panegyrick on the sense of touching . some tactile qualities , in common to the perception of other senses also . ibid. a scheme of all qualities , or commonly , or property appertaining to the sense of touching , as they stand in their several relation to , or dependencies on , the vniversal matter , atoms : and so , of all the subsequent capital arguments to be treated of , in this book . the right of rarity and density to the priority of consideration . ibid sect . ii. artic . the opinion of those philosophers , who place the reason of rarity , in the actual division of a body into small parts ; and the brief refutation thereof . ● a second opinion , de●iving ●arity and density from the several proportions , which quantity hath to its substance : convicted of incomprehensibility , and so of insatisfaction . ibid. a third , desuming the more and less of rarity in bodies , from the more and less of vacvity intercepted among their particles : and the advantages thereof above all others , concerning the same . ibid. the definitions of a rare , and of a dense body ; according to the assumption of a vacuity d●sseminate . the congruity of those definitions , demonmonstrated . ibid. that labyrinth of difficulties , wherein the thoughts of physiologists have so long wandered ; reduced to a point , the genuine state of the quaestion . ibid. that rarity and density can have no other causes immediate , but the more and less of inanity interspersed among the particles of concretions ; demonstrated . aristotles exceptions against disseminate inanity ; neither important nor c●mpetent . ibid. the hyp●the●is of a c●rt●in aethereal substance to replenish th● por●s ●f bo●ies , in ra●ifaction ; demonstrated insufficient , to solve the difficulty , or demolish the ep●cu●ean th●sis of small vacuities . the facility of understanding the reasons and manner of 〈◊〉 and condensation , from the conc●ssion of s●all vacuities , illustrated by a 〈…〉 . paradox . tha● the matter of a body , when 〈…〉 no more of true place , 〈…〉 , and the co●c●lia●ion thereof to the 〈◊〉 definitions of a rare and of a den●e bo●y . ● problem . 〈…〉 be capable of condensation to so hi●g 〈◊〉 as it is of rari●faction : and the 〈◊〉 ●olution therof . ibid. sect . iii. art c. the opportunity of the present speculation , concerning the c●uses of per●picuity and opacity . ●● the true notions of a per●picuum and opacum . ibid. that every concretion is so much the more 〈◊〉 by how much th● more , and more ample inane spaces 〈◊〉 in●●rcepted among its particles ; caeteus pa●●bus . ibid. why glass though much more dense , is yet much more diaphanous , than paper . why ●he diaphanity of glass is gradually diminished , according to the various degrees of its crassitude . ibid. an apodictical confutation of that popular error , that glass is totally , or in every particle , diaphanous . chap. x. of magnitude , figure ; and their consequents , subtility , hebetude , smoothness , asperity . sect . i. artic . the contexture of this chapter , with the praecedent . ibid. that the magnitude of concretions , ariseth from the magnitude of their material principles . ibid. the praesent intenti●n of the term , magnitude . ibid. that the ●uantity of a thing , is meerly the matter of it . ● the quantity of a thing , neither augmented by its rarefaction , nor diminished by its condensation : contrary to the aristotelians , who distinguish the q●antity of a body from its substa●ce . ibid. the reason of quantity , explicable also meerly from the notion of place . the existence of a body , without real extension ; and of extension without a body : though impossible to nature yet easie to god. ibid. corollary . that the primary cause , why nature admits no penetration of dimensi●ns , is rather the solidity , than the extension of a body . the reasons of quantity continued and d●screte , or magnitude and multitude . ibid. that no body is perfectly continued , beside an atom . ibid. aristotles d●finition of a continuum ▪ in what respect true and what false . figure ( physical●y considered ) nothing but the superficies , or terminant extremes of a body . ibid. sect . ii. artic . the continuity of this , to the first section . subtility and hebetude , how the consequents of magnitude . ibid. a considerable exception of the chymests ( viz. that some bodies are dissolved in liquors of grosser particles , which yet conserve their continuity in liquors of most subtile and corrosive particles ) prevented . ibid. why oyle dissociates the parts of some bodies , which remain inviolate in spirit of wine : and why lightning is more penetrative , than fire . smoothness and asperity in concretions , the consequents of figure in their material principles . ibid. chap. xi . of the motive vertue , habit , gravity , and levity of concretions . ● sect . i. artic . the motive virtue of all concretions , derived from the essential mobility of atoms ibid. why the motive virtue of concretions doth reside principally in their spiritual parts . that the deviation of concretions from motion direct ; and their tardity in motion : arise from the deflections and ●epercussions of atoms composing them . ibid. why the motion of all concretions necessarily praess●p●ss●th something , that remains unmoved ; or that , in respect of its slower motion , is equival●nt ●o a thing vnmoved ibid. what 〈◊〉 a●tive faculty of a thing , is . that in nature every faculty is active : none passive . ibid. a peripatetick contradiction , assuming the matter of al● bodies to be devoid of all activity ; and yet d●suming some faculties à tota substantia . that the ●aculties of animals ( the ratiocination of man onely excepted ) are identical with their spirits . ibid. the reasons of the coexistence of various faculties in one and the same concretion . ibid. habit defi●ed that the reason of all habits in animals , consisteth principally in the conformity and flexibility of the organs , which the respective faculty makes use of , for the performance of its proper actions , ibid. habits , acquirable by bruits : and common not onely to vegetables , but also to some minerals ● sect . ii. artic . gravity , as to its essence or formal reason , very obscure . the opinion of epicurus good as to the cause of comparative : insufficient as to the ●ause of absolute gravity . ibid. aristotles opinion of gravity , recited . ibid. copernicus theory of gravity , insatisfactory ; and wherein . the determination of kepler , gassendus , &c. that gravity is caused me●rly by the attraction of the earth : espoused by the author . the external principle of the perpendicular descent of a stone , projected up in the aer ; must be either depellent , or attrahent . ibid. that the resistence of the superior aer is the onely cause which gradually refracteth , and in fine wholly overcometh the im●rest force , whereby a stone projected , is elevated upward . ibid. that the aer , distracted by a stone violently ascending , hath as well a depulsive , as a resistent faculty ; arising immediately from its elaterical , or restorative motion . that nevertheless , when a stone , projected on high in the aer , is at the highest point of its mountee ; no cau●e can beg●● its downward motion , but the attractive virtue of the earth . argument , that the t●r●aqueous globe is endowed with a certain attractive faculty in order to the d●tention and retraction of a●l its parts . ● what are the parts of the terrestrialglobe a second argument that the earth is magnetical ibid. a parallelism betwixt the attraction of iron by a loadstone , and the attraction of terrene bodies by the ea●th . that as the sphere of the loadstones allective virtue is limited : so is that of the eart●s magnetism . ibid. an objection of the disproportion between the great bulk of a large stone and the exility of the supposed magnetique rays of the earth : solved by three weighty reasons . the reason of the aequivelocity of bodies , o● different weights , in their perpendicular descent : with sundry unquestionable authorities to confirm the hoti thereof . ● that the whole terrestrial globe is devoid of gravity : and that in the universe is no highest , nor lowest place . ● that the centre of the vniverse is not the lowest part thereof : nor the centre of the earth , the centre of the world a fourth argument , that gravity is onely attraction . why a greater gravity , or stronger attractive force is imprest upon a piece of iron by a loadstone , than by the earth ibid. a fifth argument , almost apodictical ; that gravity is the effect of the earths attraction . ibid. sect . iii. artic . levity nothing but less gravity . aristotles sphere of fire , extinguisht . that fire doth not as●ned spontaneously , but violently ; i. e. is impell'd upward by the aer . ibid. chap. xii . of heat and cold. p. . sect . i. artic . the connection of this to the immediately precedent chapter . ibid. why the author deduceth the first qualities , not from the vulgar elements ; but from the proprieties of atoms . ibid the nature of heat is to be conceived from its general effect ; viz. the penetration , discussion , and dissolution of the bodies concrete . ibid. heat defined as no immaterial , but a substantial quality . why such atoms , as are comparated to produce heat , are to be named the atoms of heat : and such concretions , as harbor them , are to be called hot , either actually , or potentially . ibid. the necessary proprieties of the atoms of heat . ibid. that the atoms of heat are capable of expedition or deliverance from concretions , two ways ; viz. by evocation and motion . an unctuous matter , the chief seminary of the atoms of heat : and why . among vnctuous concretions , why some are more easily inflammable than others . a consectar● . that rarefacti●n is the proper effect of heat ibid problem . why the bottom of a caldron , wherein water i● boyling , may be touched by the hand of a man , without burning it : sol. problem . why lime becomes ardent upon the affusion of 〈◊〉 . sol. problem why the heat of lime burning is more vehement , than the heat of any flame whatever . sol. ibid. problem . why boyling oyl scalds more vehemently , then boyling water . sol. problem . why metals , melted or made red hod , burn more violent than the fire , that melteth or heateth them . sol. ibid. consectary . that , as the degrees of heat , so those of 〈◊〉 are innumerably various . ibid. that to the calefaction , combustion , or ▪ inflammation of a body by fire , is required a certain space of time ; and that the space is greater or less , according to the paucity , or abundance of the igneous atoms invading the body objected ; and more or less of aptitude in the contexture thereof to admit them . ● flame more or less durable , for various respects . consectary . . that the immediate and genuine effect of heat , is the disgregation of all bodies , as well homogeneous , as heterogeneous : and that the congregation of homogeneous natures , is onely an accidental effect of heat ; contrary to aristotle . sect . ii. artic . the link connecting this section to the former . that cold is no privation of heat ; but a real and positive quality : demonstrated . ibid. that the adaequate notion of cold , ought to be desume● from its general effect , viz. the congreg●tion and compaction of bodies . cold , no immaterial ; but a substantial quality . ibid. gassendus conjectural assignation , of a tetrahedical figure to the atoms of cold ; asserted by sundry weighty considerations . ibid cold , not essential to earth , water , nor aer . but to some special concretions , for the most part , consisting of frigorifick atoms . water ▪ the chief antagonist to fire ; not in respect of its accidental frigidity , but essential humidity : and that the aer hath a juster title to the principality of cold , than either water , or earth . problem : why the breath of a man doth warm , when expired with the mouth wide open ; and cool , when efflated with the mouth contracted . ibid. three consectaries from the premises . chap. xiii . fluidity , stability , humidity , siccity . p. . sect . i. artic . why fluidity and firmness are here considered before humidity and siccity . ibid. the latin terms , humidum and siccum , too narrow to comprehend the full sense of aristotle , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ibid. the latin terms , humidum and siccum , too narrow to comprehend the full sense of aristotle . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . ibid. aristotles definition of a humid substance , not praecise enough ; but , in common also to a fluid ; and his definition of a dry , accommodable to a firme . fluidity defined . wherein the formal reason thereof doth consist . ibid. the same farther illustrated , by the twofold fluidity of metals ; and the peculiar reason of each . firmness defined : and derived from either of causes . ibid. sect . ii. artic . humidity defined . siccity defined . siccity rather comparative than absolute . ibid all moisture either aqueous or oleaginous . ibid. problem ● . why pure water cannot wash out oyl from a cloth ; which yet water , wherein ashes have been decocted , or soap dissolved , easily doth ? solut. problem . why stains of ink are not to be taken out of cloaths , but with some acid liquor ? solut. ibid. chap. xiv . softness , hardness , flexility ▪ tractility , ductility , &c. p. . sect . i. artic . the illation of the chapter . ibid. hard and soft , defined . ibid. the difference betwixt a soft and fluid . solidity of atoms , the fundament of hardness and inanity intercepted among them , the fundament of softness , in all concretions . ibid. hardness and softness , no absolute , but meerly comparative qualities ; as adscriptive to concretions , contrary to aristotle . softness in firme things , deduced from the same cause , as fluidity in fluid ones . ibid. the general reason of the mollification of hard , and induration of soft bodies . ibid. the special manners of the m●llification of hard : and induration of soft bodies . problem why iron is hardned , by being immersed red-hot into cold water ; and its solvtion . ibid. the formal reasons of softness and hardness . the ground of aristotles distinction betwixt formatilia and pressilia . ibid. two axioms , concerning , and illustrating the nature of softness . sect . ii. artic . flexility , tractility , ductility , &c. derived from softness , and rigidity from hardness ● problem . what is the cause of the motion of restoration in flexiles ? and the solut. ibid. two obstructions expeded . why flexile bodies grow weak , by overmuch , and over frequent bending the reason of the frequent vibrations , or diadroms of lutestrings , and oth●r tractile bodies ; declared to be the same with that of the restorative motion of flexiles : and demonstrated . ibid. problem . why the vibrations , or diodroms of a chord distended and percussed , are aequitemperaneous , though not aequispatial : and the solvt . problem . vvy doth a chord of a duple length , perform its diadroms in a proportion of time duple , to a chord of a single length ; both being distended by equal force ; and yet if the chord of the duple length be distended by a duple force or weight , it doth not perform its diadroms , in a proportion of time duple to that of the other ; but onely if the force or weight distending it , be quadruple to the first supposed : and its solvt . the reasons of the vast ductility , or extensibility of gold. sectility and fissility , the consequents of softness . ibid. tractility and friability , the consequents of hardness . ruptility the consequent partly of softness , partly of hardness . problem . vvhy chords distended , are more apt to break neer the ends , than in the middle ? and its solvt . ibid. chap. xv. occult qualities made manifest . p. sect . i. artic . that the insensibility of qualities doth not import their unintelligibility ; contrary to the presumption of the aristotelean . ibid. vpon what grounds ; and by whom , the sanctuary of occult qualities was erected . occult qualities and profest ignorance , all one . ibid. the refuge of sympathies and antipathies , equally obstructive to the advance of natural scienee , with that of ignote proprieties . that all attraction , referred to secret sympathy ; and all repulsion , adscribed to secret antipathy , betwixt the agent and patient , is effected by corporeal instruments , and such as resemble those whereby one body attracteth , or repelleth another , in sensible and mechanique operations . ibid. the means of attractions sympathetical , explicated by a convenient simile . the means of abaction and repulsions antipathetical , explicated likewise by sundry similitudes . the first and general causes of all love and hatred betwixt animals . why things alike in their natures , love and delight in the society each of other : and why unlike natures abhor and avoid each other . ibid sect . ii. artic . the scheme of qualities ( reputed ) occult . natures avoidance of vacuity , imputed to the tyzugia or conspiration of all parts of the vniverse ; no occult quality . ibid. the power and influence of caelestial bodies , upon men , supposed by judicial astrologers , inconsistent with providence divine , and the liberty of mans will. the afflux and reflux of the sea , inderivative from any immaterial influx of the moon . ibid. the causes of the diurnal expansion & conversion of the heliotrope and other flowers . ibid. why garden claver hideth its stalk , in the heat of the day . why the house cock usually crows soon after midnight ; and at break of day . ibid. why shell-fish grow fat in the full of the moon , and lean again at the new. why the selenites resembles the moon in all her several adspects . ibid. why the consideration of the attraction of iron by a loadstone , is here omitted . the secret amities of gold and quicksilver of brass and silver , unridled . ibid. a corollary . why the granules of gold and silver , though much more ponderous then those of the aqua regis and aqua ●ortis , wherein they are dissolved , are yet held up , and kept floating by them . the cause of the attraction of a less flame by a greater . ibid. the cause of the involation of flame to naphtha at distance . ibid. of the ascention of water into the pores of a spunge . the same illustrated by the example of a syphon . ibid. the reason of the percolation of liquors , by a cloth whose one end lieth in the liquor , and other hangs over the brim of the vessel , that contains it . the reason of the consent of two lute-strings , that are aequison . ibid. the reason of the dissent betwixt lutestrings of sheeps guts , and those of woolfs . ● the tradition of the consuming of all feathers of foul , by those of the eagle ; exploded . why some certain plants befriend , and advance the growth and fruitfulness of others , that are their neighbours . ibid. why some plants thrive not in the society of some others . the reason of the great friendship betwixt the male and female palm-trees . why all wines grow sick and turbid , during the season wherein the vines flower and bud. that the distilled waters of orange flowers , and roses , do not take any thing of their fragrancy , during the season of the blooming and pride of those flowers ; as it vulgarly believed . ibid. sect . iii. artic . why this section considers onely some few select occult proprieties , among those many imputed to animals . the supposed antipathy of a sheep to a woolf solved . ibid. why bees usually invade froward and cholerick persons : and why bold and confident men haue sometimes daunted and put to flight , lyons and other ravenous wild-beasts . why divers animals hate such men , as are used to destroy those of their own species : and why vermin avoid such gins and traps , wherein others of their kinde have been caught and destroyed . ibid. the cause of the fresh cruentation of the carcass of a murthered man , at the presence and touch of the homicide . how the basilisk doth empoyson and destroy , at distance . that the sight of a woolf doth not cause hoarsness and obmutescence in the spectator ; as is vulgarly reported and believed . the antipathies of a lyon and cock : of an elephant and swine meerly fabulous . ● why a man intoxicated by the venome of a tarantula , falleth into violent fits of dancing : and cannot be cured by any other means , but musick . ibid. why divers tarantiacal persons are affected and cured with divers tunes , and the musick of divers instruments . that the venome of the tarantula doth produce the same effect in the body of a man ; as it doth in that of the tarantula it self : and why . ibid. that the venom of the tarantula is lodged in a viscous humor , and such as is capable of sounds . that it causeth an uncessant itching and titillation in the nervous and musculous parts of mans body , when infused into it , and fermenting in it . ibid. the cause of the annual recidivation of the tarantism , till it be perfectly cured . a conjecture , what kind of tunes , strains , and notes seem most accommodate to the cure of tarantiacal persons in the general . ibid the reason of the incantation of serpents , by a rod of the cornus . digression . that the words . spells , characters , &c. used by magicians , are of no vertue or efficacy at all , as to the effect intended ; unless in a remote interest , or as they exalt the imagination of him , upon whom they praetend to work the miracle . ibid. the reason of the fascination of infants , by old women ▪ the reason of the stupefaction of a mans hand by a torpedo . that ships are not arrested in their course , by the fish called a remora : but by the contrary impulse of some special current in the sea. ibid. that the echineis , or remora is not ominous . ● why this place admits not of more than a general inquest into the faculties of poysons and counterpoisons . ibid. poysons defined . ibid. wherein the deleterious faculty of poyson doth consist . ibid. counterpoisons defined . wherein their salutiferous virtue doth consist . ibid. how triacle cureth the venome of vipers . ibid how the body of a scorpion , bruised and laid warm upon the part , which it hath lately wounded and envenomed ; doth cure the same . that some poisons are antidotes against others by way of direct contrariety . ibid. why sundry particular men , and some whole nations have fed upon poisonous animals and plants , without harm· the armary unguent , and sympathetick powder , impugned . ibid. the authors retraction of his quondam defence of the magnetick cure of wounds , made in his prolegomena to helmonts book of that subject and title . chap. xvi . the phaenomena o● the loadstone explicated ▪ p. . sect . i. artic . the nature and obscurity of the subject , hinted by certain metaphorical cognomina , agreeable thereunto , though in divers relations . ibid. why the author insisteth not upon the ( ) several appellations , ( ) inventor of the loadstone , ( ) invention of the pixis nautica . the virtues of the loadstone , in general , two , the attractive , and directive . ibid. epicurus his first theory of the cause and manner of the attraction of iron by a loadstone ; according to the exposition of lucre●ius . ibid ▪ his other solution of the same , according to the commentary of galen . galens three grand objections against the same , briefly answered . the insatisfaction of the ancients theory necessitates the author to recur to the speculations and observations of the moderns , concerning the attraction of iron by a magnet ; and the reduction of them all to a few capital observables . viz. a parallelism betwixt the magnetique faculty of the loadstone and iron ; and that of sense in animals . that the loadstone and iron interchangeably operate each upon other , by the mediation of certain corporeal species , transmitted in ●ays : and the analogy of the magnetick , and luminous rayes . that every loadstone , in respect of the circumradiation of its magnetical aporrhae's ought to be allowed the supposition of a centre axis , and diametre of an aequator : and the advantages thence accrewing . the reason of that admirable bi-form , or janus-like faculty of magneticks : and why the poles of a loadstone are incapable , but those of a needle easily capable of transplantation from one extreme to the contrary . an objection , of the aversion or repulsion of the north pole of one loadstone , or needle , by the north pole of another : praevented . three principal magnetick axioms , deduced from the same fountain . ibid. a digression to the iron tomb of mahomet . that the magnetique vigour , or perfection both of loadstones and iron , doth consist in either their native purity and vniformity of substance , or their artificial politeness . that the arming of a magnet with polished steel , doth highly corroborate ; but as much diminish the sphere of its attractive virtue . ibid. why a smaller or weaker loadstone , doth snatch away a needle from a greater , or more potent one ; while the small or weak one is held within the sphere of the great or stronger ones activity : and not otherwise . corollary . of the abduction of iron from the earth by a loadstone . sect . ii. artic . the method , and contents of the sect. ibid. affinity of the loadstone and iron . ibid. the loadstone conforms it self , in all respects , to the terrestrial globe ; as a needle conforms it self to the loadstone . iron obtains a verticity , not onely from the loadstone , by affriction ▪ or aspiration ; but also from the earth it self : and that according to the laws of position . one and the same nature , in common to the earth , loadstone and iron . the earth , impragnating iron with a polary affection , doth cause therein a local immutation of its insensible particles . the loadstone doth the same . the magnetique virtue , a corporeal efflux . ib. contrary objections , and their solution● ▪ a parallelism of the magnetique virtue , and the vegetative faculty of plants why poles of the same respect and name , are enemies : and those of a contrary respect and name , friends . when a magnet is dissected into two pieces , why the boreal part of the one half , declin●s conjunction with the b●rea● part of the other ; and the austral of one with the austral of the other . ibid. the fibres of the earth extend from pole to pole ; and that may be the cause of the firm cohaesion of all its parts , conspiring to conserve its spherical figure . reason of magnetical variation , in divers climates and places . ibid. the decrement of magnetical variation , in one and the same place , in divers years . the cause thereof not yet known . ibid. no magnet hath more than two legitimate poles : and the reasons of illegitimate ones the conclusion , apologetical ; and an advertisement , that the attractive and directive actions of magnetiques , arise from one and the same faculty ; and that they were distinguished onely 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , for convenience of doctrine . the fourth book . chap. i. of generation and corruption . p. sect . i. artic . the introduction . ibid the proper notions of generation and corruption . ● various opinions of the ancient philosophers , touching the reason of generation : and the principal authors of pacti . the two great opinions of the same philosophers concerning the manner of the commistion of the common principles in generation ; faithfully and briefly stated . that of aristotle and the stoicks , refuted : and chrysippus sub●ersuge , convicted of absurdities . aristotles twofold evasion of the incongruities attending the position of the remane●ce of things commixed , notwithstanding their supposed reciprocal transubstantiation : found lik●wise meerly s●phistical . that the f●rms of things , arising in generation ▪ are no new substances , nor distinct from th●ir matter : contrary to the aristoteleans . that the form of a thing , is onely a certain quality , or determinate modification of its matter . an abstract of the theory of the atomists , touching the same . ● an illus●ration thereof , by a praegnant and ●pportu●● i●stance . viz. the gen●ration of fire , flame , fume , soot , ashes , and salt , from wood dissolved by fire . ● sect . ii. artic . that in corruption , no substance perisheth ; but only that determinate modification of substance , or matter , which specified ●he thing . enforcement of the same thesis by an illustrious example . an experiment demonstrating that the salt of ashes was praeexistent in wood ; and not produced , but onely educed by fire . ibid. the true sense of three general axioms , deduced from the precedent doctrine of the atomists . ● the general intestine causes of corruption , chiefly two : ( ) the interception of inanity among the solid particles of bodies . ( ) the essential gravity and inseperable mobility of atoms . the general manners , or ways of generation and corruption . inadvertency of aristotle in making five general modes of generation . the special manners of generation , innumerable ▪ and why . ibid. all sorts of atoms , not indifferently competent to the constitution of all sorts of things . chap. ii. of motion . p. . sect . i. artic . why the nature of motion , which deserved to have been the subject of the first speculation , was reserved to be the argument of the last , in this physiology . ibid. an epicurean principle , of fundamental concern to motion . aristotles position , that the first principle of motion , is the very forme of the thing moved ; absolutely incomprehensible : unless the form of a thing be conceived to be a certain tenuious contexture of most subtile and most active atoms . ibid. a second epicurean fundamental , concerning motion : and the state of the difference betwixt epicurus , aristotle , and plato , touching the same . ● epicurus's definition of motion , to be the remove of a body from place to place ; much more intelligible and proper , than aristotles , that it is the act of an entity in power , as it is such . empericus his objections against that definition of epicurus : and the full solution of each . that there is motion ; contrary to the sophisms of parmenides , melissus , zeno , diodorus and the scepticks . sect . ii. artic . aristotles definitions of natural and violent motion ; incompetent ▪ and more adaequate ones substituted in the room of them . the same deduced from the first epicurean principle of motion , praemised : and three considerable conclusions extracted from thence . a short survey of aristotles whole theory concerning the natural motion of inanimates : and the errors thereof . uniformity , or aequability , the proper character of a natural motion : and the want of uniformity , of a violent . the downward motion of inanimates , derived from an external principle ; contrary to aristotle . that that external principle , is the magnetique attraction of the earth that the vpward motion of light things , is not accelerated in every degree of their ascent as aristotle praecariously affirmed : but , the downward motion of heavy things is accelerated in every degree of their descent ▪ ibid the cause of that encrease of velocity in bodies descending ; not the augmentation of their specifical perfection as they approach neerer and neerer to their proper place : as simplicius makes aristotle to have thought . nor the diminution of the quantity of aer underneath them : as some others conjectured . ibid. nor , the gradual diminution of the force imprest upon them , in their projection upward : as hipparchus alleadged . but , the magnetique attraction of the earth . ibid. that the proportion , or ration of celerity to celerity , encreasing in the descent of heavy things ; is not the same as the proportion , or ration of space to space , which they pervade : contrary to michael varro the mathematician . but , that the moments or equal degrees of celerity , carry the same proportion , as the moments or equal degrees of time , during the motion : according to the illustrious galilaeo . galilaeo's grounds , experience , and reason . the same demonstrated . the physical reason of that proportion . the reason of the equal velocity of bodies of very different weights , falling from the same altitude ; inferred from the same theory . ibid. gravity distinguish't into simple , and adjectitious . the rate of that superlative velocity with which a bullet would be carried , in case it should fall from the moon , sun or region of the fixed stars , to the earth : and from each of those vast heights , to the centre of the earth . sect . iii. artic . what , and whence is that force , or virtue motive , whereby bodies projected are carried on after their dismission from the projicient . the m●nner of the impression of that force . that all m●tion , in a free or empty space , must be vniform , and perpetual : and that the chief cause of the inequality and brevity of the motion of things projected through the atmosphere , is the ma●netique attraction of the earth . that , in the atmosphere , no body can be projected in a direct line ; unless perpendicularly vpward , or downward : and why . that the motion of a stone proj●cted upwards obliquely , is composed of an horizontal and perpendicular together . ibid. demonstration of that composition . that of the two different forces , impressed upon a ball , thrown upward from the hand of a man standing in a ship , that is under sayl : the one doth not destroy the other , but each attains its proper scope . ibid. that the space of time , in which the ball is ascending from the foot to the top of the mast : is equal to that , in which it is again descending from the top to the foot . that , though the perpendicular motion of a stone thrown obliquely upward , be unequal , both in its ascent and descent : yet is the horizontal of equal velocity in all parts of space . ibid. the reason and manner of the reflexion or rebounding motion of bodies , diverted from the line of their direction by others encountring them . that the emersion of a weight appensed to a string , from the perpendicular , to which it had reduced it self , in vibration ; is a reflexion median betwixt no reflexion at all , and the least reflexion assignable ; and the rule of all other reflexion whatever . the reason of the equality of the angles of incidence and reflexion . ibid. two inferences from the praemises : viz· ( ) that the oblique projection of a globe against a plane , is composed of a double parallel : and ( ) that nature suffers no diminution of her right to the shortest way , by reflexion . wherein the aptitude or ineptitude of bodies to reflexion doth consist . ibid. book the first . chap. i. all modern philosophers reduced to four general orders ; and the principal causes of their dissention . sect . i. if we look back into the monuments or remains of antiquitie , we shall observe as many several sects of philosophers , as were the olympiads in which greece wore the imperial diadem of letters ; nay , perhaps , as many as she contained academies , and publike professors of arts and sciences : each master affecting to be reputed the principal secretary of nature ; and his disciples ( their minds being deeply imbued with his principles ) admiring him as the grand oracle of divinitie , and the infallible dictator of scientifical maxims . the chiefest , most diffused , and most memorable of these sects , were the pythagorean , the stoick , the platonist , the academick , the peripatetick , the epicurean , and what , derided all the rest , the pyrrhonian , or sceptick ; which feircely contended for the laurel , by subtle disputations on the side of absolute ignorance , and aspired to the monarchy of wisdom , by detecting the vanitie and incertitude of all natural science . as for the megarick , eretrick , cyreniack , annicerian theodorian , cynick , eliack , dialectick , and others less famous ; diogenes laertius , ( de vita philosophor . ) hath preserved not only a faithful catalogue of them , but hath also recorded their originals , declinations , periods , opinions . if we enquire into the modern state of learning , down even to our present age , we cannot but find not only the same sects revived , but also many more new ones sprung up : as if opinion were what mysterious poets intended by their imaginary hydra ; no sooner hath the sword of time cut off one head , but there grows up two in the place of it ; or , as if the vicissitudes of corruption and generation were in common as well to philosophy , as the subject of it , nature . insomuch as that adage , which was principally accommodated and restrained to express the infinite dissention of vulgar and unexamining heads , tot sententiae quot homines ; may now justly be extended also to the scholiarchs and professed enquirers into the unitie of truth . to enumerate all these modern dissenting doctors ( the most modest of all which hath not blushed to hear his pedantique disciples salute him with the magnificent attributes of a despot in physiologie , and the only cynosure by which the benighted reason of man may hope to be conducted over the vertiginous ocean of error , to the cape of veritie ) is neither useful to our reader , nor advantageous or pertinent to our present design . but , to reduce them to four general orders , or range them into four principal classes ; as it may in some latitude of interest , concern the satisfaction of those who are less conversant among books : so can it in no wise affront the patience of those , whose studies have already acquainted them with the several kinds of philosophy now in esteem . some there are ( and those not a few ) who in the minority of their understandings , and while their judgments are yet flexible by the weak fingers of meer plausibilitie , and their memories like virgin wax , apt to retain the impression of any opinion that is presented under the specious disguise of verisimilitie only ; become constant admirers of the first author , that pleaseth them , and will never after suffer themselves to be divorced from his principles , or to be made proselytes to truth ; but make it the most serious business of their lives to propugne their tutors authoritie , defend even his very errors , and excogitate specious subterfuges against those , who have with solid arguments and apodic●ical reasons , clearly refuted him . these stifle their own native habilities for disquisition , believe all , examine nothing ; and , as if the lamp of their own reason were lent them by their creator for no use at all , resign up their judgments to the implicite manuduction of some other ; and all the perfection they aim at , is to be able to compose unnecessary , and perhaps erroneous commentaries upon their masters text . this easie sect may , without much either of incongruitie or scandal , be named secta 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , the femal sect ; because as women constantly retain their best affections for those who untied their virgin zone ; so these will never be alienated from immoderately affecting those authors who had the maiden ▪ head of their minds . the chiefest chair in this classis ought to be consigned to our iunior aristoteleans , who villifie and despise all doctrine , but that of the stagirite , and confidently measure all mens deviations from truth , by their recessions from his dictates . this we say not to derogate from the honour due to so great a clerk ; for we hold it our duty to pay him as large a tribute of veneration , as any man that ever read his excellent writings , without prejudice , and esteem him as 〈◊〉 of the greatest and brightest stars in the sphere of learning ; nay we dare assert , that he was the centre in which all the choicest speculations and observations of his praedecessors were united , to make up as complete abody of natural science , as the brain of any one single person , wanting the illumination of sacred writ , seems capable of , in this life of obscuritie : and that he hath won the garland from all , who have laboured to invent and praescribe a general method for the regulation and conduct of mens cogitations and conceptions . but , that i am not yet convicted , that his judgment was superior to mistake ; that his writings , in many places more then obscure , can well be interpreted by those who have never perused the moniments of other ancients ; nor , that it can consist with ingenuity to institute a sacrament in philosophy , ( i. e. ) to vow implicite vassalage to the authoritie of any man , whose maxims were desumed from no other oracle , but that of natural reason only ; and to arrest all curiositie , disquisition , or dubitation , with a meer 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . hither may we refer also the patient interpreters of scotus ; the vain idolaters of raimund lully ; but , above all , the stupid admirers of that fanatick drunkard , paracelsus . in whose whole life , the only rarities any sober man can discover were his fortune , and his impudence . his fortune , in that he being an absolute bankrupt in merit , could be trusted with so large a stock of fame : his impudence , in that , being wholly illiterate ( for in stead of refining , he much corrupted his mother-tongue ) he should praetend to subvert the fundamentals of aristotle and galen , to reform the common-weal of learning , consummate the arts and sciences , write commentaries on the evangelists , and enrich the world with pansophy in aphorisms . ( ) others there are ( and those too few ) whose brests being filled with true promethean fire , and their minds of a more generous temper , scorn to submit to the dishonourable tyranny of that usurper , autority , and will admit of no monarchy in philosophy , besides that of truth . these ponder the reasons of all , but the reputation of none ; and then conform their assent , when the arguments are nervous and convincing ; not when they are urged by one , whose name is inscribed in golden characters in the legend of fame . this order well deserves the epithite , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and therefore we shall christen it , the order of the assertors of philosophical liberty ; in regard , they vindicate the native privilege of our intellectuals , from the base villenage of praescription . of this order , gratitude it self doth oblige us to account the heroical tycho brahe , the subtle kepler , the most acute galilaeus , the profound scheinerus , the miraculous because universally learned kircherus , the most perspicacious harvey , and the epitome of all , des cartes . in honour of each of these hero's , we could wish ( if the constitution of our times would bear it ) a colossus of gold were erected at the publick charge of students ; and under each this inscription : amicus plato , amicus aristoteles , magis amica veritas . ( ) the third classis is possessed by such , who , without either totally neglecting or undervaluing the inventions and augmentations of the modern ; addict themselves principally to research the moniments of the ancients , and dig for truth in the rubbish of the grecian patriarchs . these are the noblest sort of chymists , who labour to reform those once-excellent flowers out of their ashes : worthy geometricians , that give us the true dimensions of those giant wits , by the measure of their feet : and genuine ●ons of aesculapius , who can revive those , whom the fleet chariot of time hath dragg'd to pieces , and recompose their scattered fragments into large and complete bodies of physiologie . the course of these worthies in their studies doth denominate them 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , renovators . for , being of opinion , that philosophy as well as nature doth continually decline , that this is the dotage of the world , and that the minds of men do suffer a sensible decay of clarity and simplicity ; they reflect their thoughts upon the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or epoche of physical writings , ransack the urns of athens to find out the medal of some grave philosopher , and then with invincible industry polish off the rust , which the vitriolate dampness of time had superinduced ; that so they may render him to the greedy eyes of posterity in his primitive splendor and integrity . the uppermost seats in this infinitely-deserving classis justly belong to marcilius ficinus , who from many mouldy and worm-eaten transcripts hath collected , and interpreted the semidivine labors of plato : to copernicus , who hath rescued from the jawes of oblivion , the almost extinct astrology of samius aristarchus : to lucretius , who hath retrived the lost physiologie of empedocles : to magnenus , who hath lately raised up the reverend ghost of democritus : to mersennus , who hath not only explained many problems of archimed ; but renovated the obsolete magick of numbers , and charmed the most judicious ears of musitians , with chiming pythagoras hammers , in an arithmetick harmony : and to the greatest antiquary among them , the immortal gassendus ; who , out of a few obscure and immethodical pieces of him , scattered upon the rhapsodies of plutarch and diogenes laertius , hath built up the despised epicurus again , into one of the most profound , temperate , and voluminous among philosophers . our fourth classis is to be made up of those , who indeed adore no authority , pay a reverend esteem , but no implicite adherence to antiquity , nor erect any fabrick of natural science upon foundations of their own laying : but , reading all with the same constant indifference , and aequanimity , select out of each of the other sects , whatever of method , principles , positions , maxims , examples , &c. seems in their impartial judgments , most consentaneous to verity ; and on the contrary , refuse , and , as occasion requires , elenchically refute what will not endure the test of either right reason , or faithful experiment . this sect we may call ( as potamon alexandrinus , quoted by diogenes laertius , long before us ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 the electing , because they cull and select out of all others , what they most approve . herein are chairs provided for those worthies , fernelius , sennertus , and most of the junior patriots and advancers of our art. and the lowest room , we ask leave to reserve for our selves . for ▪ we profess our selves to be of his perswasion , who saith ; ego quidem arbitror , re diu perpensâ , nullius unquam scientiam fore absolutam , quin empedoclem , platonem , aristotelem , anaxagoram , democritum adjungat recentioribus , & ab un●quoque quod verum est , rejectis falsis , eligat . his enim principibus peculi●ri ratione coeleste lumen affulsit : & quamvis corporis imbecilitate multa corruperint ; plurima tamen , quae fidei lumine discernimus , scripsêre verissima he can never make a good chymist , who is not already an excellent galenist , is proverbial among us physicians : and as worthy the reputation of a proverb is it among professors in universities ▪ he can never clearly understand the moderns , who remains ignorant of the doctrines of the antients . here to declare our selves of this order , though it be no dishonour , may yet be censured as superfluous : since not only those exercises of our pen , which have formerly dispersed themselves into the hands of the learned , have already proclaimed as much ; but even this praesent tractate must soon discover it . sect . ii. to explore the cheif grounds , or reasons of this great varietie of sects in philosophy ; we need search no further , then the exceeding obscurity of nature , the dimness and imperfection of our understanding , the irregularity of our curiosity . of the first , they only can doubt , who are too stupid to enquire . for , nature is an immense ocean , wherein are no shallows , but all depths : and those ingenious persons , who have but once attempted her with the sounding line of reason , will soon confess their despair of profounding her , and with the judicious sanchez sadly exclaim ; una scientia sufficit toti orbi : nec tamen totus hic ei sufficit . mihi vel minima mundi res totius vitae contemplationi sat est superque : nec tamen tandem eam spero me nosse posse : nor can they dislike the opinion of the academicks and pyrrhonicks , that all things are incomprehensible . and ( as for the second ) if nature were not invelloped in so dense a cloud of abstrusity , but should unveil her self , and expose all her beuteous parts naked to our speculation : yet are not the opticks of our mind either clear or strong enough to discern them . men indeed fancy themselves to be eagles ; but really are grovelling moles , uncessantly labouring for light : which at ●irst glimpse perstringeth their eyes , and all they discover thereby , is their own native blindness . naturae mysteria etiamsi ●ille facibus revelentur , arbitrantium oculis numquam tota excipientur : restabit semper quod quaeras ; & quo plus scies , eo plura à te ignorari miraberis . this meditation , we confess , hath frequently stooped our ambitious thoughts , dejected us even to a contempt of our own nature , and put us to a stand in the midst of our most eager pursuit of science : insomuch that had not the inhaerent curiosity of our genius sharply spurred us on again , we had totally desisted , and sate down in this resolution ; for the future to admire , and perhaps envy the happy serenity of their condition , who never disquiet and perplex their minds with fruitless scrutiny , but think themselves wise enough , while they acquiesce in the single satisfaction of their senses . nor do we look ever to have our studies wholly free from this damp : but expect to be surprised with many a cold fit , even then when our cogitations shall be most ardent and pleasing . and to acknowledge our pensive sense of this discouragement , is it that we have chosen this for our motto : quo magis quaerimus ▪ magis dubitamus . but lest this our despair prove contagious , and infect our reader , and he either shut up our book , or smilingly demand of us , to what purpose we wrote it ; if ( as we confess ) insatisfaction be the end of study , and ( as we intimate ) our phisiology at most but ingenious conjecture : we must divert him with the novelty of a paradox , viz. that the irregularity of our curiosity is one cause of the dissent of philosophers . that our desire of truth should be a grand occasion of our error ; and that our first parents were deluded more by the instigation of their own essential curiosity , than by either the allurement of their sensual appetite or the subtle fallacies of the serpent : is a conceit not altogether destitute of thesupport and warrantry of reason . for , the human soul ( the only creature , that understands the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or transcendent dignity of its original , by reflecting upon the superlative idea , which it holds of its creator ) from the moment of its immersion into the cloud or opacity , of flesh labours with an insatiable appetence of knowledge ; as the only means , that seems to conduce to the satisfaction of its congenial ambition of still aspiring to greater and better things : and therefore hath no affection either so essential , or violent , as the desire of science ; and consequently , lyeth not so open to the deception of any objects , as of those which seem to promise a satisfaction to that desire . and obvious it is from the words of the text ; that the argument which turned the s●ales , i. e. determined the intellect , and successively the will of our grandmother eve , from its indifferencie , or aequilibration , to an appetition , and so to the actual degustation of the forbidden fruit , was this : desiderabilis est arboris fructu● ad habendam scientiam . besides , though we shall not exclude the beauty of the fruit , transmitted by the sight to the judicatory faculty , and so allecting the sensual appetite , from having a finger in the delusion : yet can we allow it to have had no more then a finger ; and are perswaded , that in the syndrome or conspiracy of causes , the most ponderous and praevalent was the hope of an accession or augmentation of knowledge . since ●t cannot but highly disparage the primitive or innocent state of man , to admit , that his intellect was so imperfect , as not to discern a very great evil , through the thin apparence of good , when the utmost that apparence could promise , was no more , than the momentany pleasure of his palate or gust : or , that the express and poenal interdiction of god , yet sounding in his ears , could be over-balanced by the light species of an object , which must be lost in the fruition . nor is this curiositie to be accused only of the first defection from truth , but being an inseparable annex to our nature , and so derived by traduction to all adams posteritie , hath proved the procatarctick cause of many ( some contemplative clerks would have adventured to say of all ) the errors of our judgments . and , though we have long cast about , yet can we not particular any one vicious inclination , or action , whose scope or end may not , either directly or obliquely , proximly or remotely , seem to promise an encrease of knowledge in some kind or other . to instance in one , which appears to be determined in the body , to have no interest beyond the sense , and so to exclude all probabilitie of extending to the mind , as to the augmentation of its science . whoever loves a beutiful woman , whom the right of marriage hath appropriated to another , ardently desires to enjoy her bed ; why , not only for the satisfaction of his sensual app●tite , because that might be acquired by the act of carnali●y with some other less beutiful , and beuty is properly the object of the mind : but because that image of beuty , which his eye hath transmitted to his mind , being praesented in the species or apparition of good and amiab●e , seems to contain some excellence , or comparitively more good , then what he hath , formerly understood . if it be objected , that if so , one enjoyment must satisfie that desire ; and consequently , no man could love what he hath once enjoyed , since fruition determineth desire : we answer , that there is no such necessitie justly inferrible , when experience assures , that many times love is so far from languishing , that it grows more strong and violent by the possession of its object . the reason is , because the passionate lover , apprehending no fruition total ▪ or possession entire , supposeth some more good still in the object , then what his former enjoyment made him acquainted withall . and if it be replyed , that the lover doth , in the perseverance of his affection , propose to himself meerly the continuation of that good , which he hath formerly enjoyed : we are provided of a sufficient rejoynder , viz. that whoso wisheth the continuation of a good , considers it not as a thing praesent , but to come ; and consequently as a thing which yet he doth not know : for , no man can know what is not . other instances the reader may be pleased to select from among the passions ; tracing them up to their first exciting cause , in order to his more ample satisfaction : it being digressive and only collateral to our scope . good thus being the only proper object of our affections ( for evil exhibited naked , i. e. as evil , never attracts , but ever averts our will , or rational appetite : as we have clearly proved in our discourse of the liberty elective of mans will. ) if we mistake a real evil praesented under the disguise of a good : this mistake is to be charged upon the account of our rational or judicatory faculty , which not sufficiently examining the reality of the species , judgeth it to be good , according to the external apparence only ; and so misguideth the will in its election . now , a●ong the causes of the intellects erroneous judicature ( we have formerly touched upon its own native imperfection , or coecity , and praejudice , ) the chiefest and most general is the impatience , praecipitancy , or inconsiderateness of the mind ; when , not enduring the serious , profound , and strict examen of the species , nor pondering all the moments of reason , whi●h are on the averting part of the object , with that impartiali●y requisite to a right judgment ; but suffering it self , at the first occursion or praesentation thereof , to be determined , by the moments of reason apparent on the attracting part , to an approbation thereof : it misinformeth the will , and ingageth it in an election and prosecution of a falsity , or evil , couched under the specious semblance of a positive truth , or good. now , to accommodate all this to the interest of our paradox ; if good , real or apparent , be the proper and adaequate object of the intellect ; and the chief reason of good doth consist in that of science , as the principal end of all our affections : then , most certainly , must our praecedent assertion stand firm , viz. that our understanding lyeth most open to the delusion of such objects , which by their apparence promise the most of satisfaction to our desire of science ; and , upon consequence , by how much the more we are spurred on by our curiosity , or appe●ence of knowledge , by so much the more is our mind impatient of their strict examen , and aequitable perpension . all which we dayly observe experimented in our selves . for , when our thoughts are violent and eager in the pursuit of some reason for such or such an operation in nature ; if either the discourse , or writings of some person , in great esteem for learning or sagacity , or our own meditations furnish us with one , plausible and verisimilous , such as seems to solve our doubt : how greedily do we embrace it , and without further perpension of its solidity and verity , immediately judge it to be true , and so set up our rest therein ? now , it being incontrovertible , that truth consists in a point , or unity ; it remains as incontrovertible , that all those judgements , which concur not in that point , must be erroneous : and consequently that we ought ever to suspect a multiplicity of dissenting j●dgments , and to suppose that phaenomenon in nature to be yet in the dark , i. e. uncomprehended , or not understood , concerning whose solution the most various opinions have been erected . and thus have we made it out ; that our curiosity is the most frequent cause of our minds impatience or praecipitancy : that praecipitancy the most frequent cause of our erroneous jdugments , concerning the verity or falsity of objects : those erroneous judgments alwayes the cause of the diversity of opinions : and the diversity of opinions alwayes the cause of the variety of sects among philosophers . chap. ii. that this world is the vniverse . sect . i. among those fragments of antiquity , which history hath gathered up from the table of sated oblivion , we find two worthy the entertainment of our readers memory , though , perhaps , not easie to be digested by his belief . the one that alexander the great grew melancholy at the lecture of anaxarchus his discourse of an infinity of worlds , and with tears lamented the confinement of his ambition to the conquest of one : when yet , in truth , the wings of his victory had not flown over so much as a third part of the terrestrial globe ; and there remained nations more then enough to have devoured his numerous armies at a breakfast , to have learned him the unconstancy of fortune , the instability of empire , and the vanitie of pride , by the experiment of his own overthrow , and captivity in a narrow prison . the other , that there were whole schools of philosophers , who fiercely contended for a plurality of worlds , and affected the honour of invincible wits , by extending their disquisitions beyond the extrems or confines of this adspectable world to a multitude of others without it , as vast , as glorious , as rich in variety of forms : when , indeed , their understandings came so much short of conquering all the obvious difficulties of this one , that even the grass they trod on , and the smallest of insects , a handworm , must put their curiosity to a stand , reduce them to an humble acknowledgment of their ignorance , and make them sigh out the scepticks motto , nihil scitur , for a palinodia . whether his or their ambition were the greater , is not easie to determine ; nor can we find more wildness of phansy , or more insolent rhodamontadoes in camps , than academies , nay if we go to absurdities , cedunt arma togae , the sword must give place to the gown . but , that his error was more venial then theirs , is manifest from hence ; that he had conquered all of the world that he knew : but they could not but find themselves foiled and conquered by eve●y the most minute and sensible part of the world , which they had attempted to know . this genus of philosophers doth naturally divide it self into two distinct species . the first of which doth consist of those , who assert only a plurality of worlds : the second of those , who have been so bold as to ascend even to an infinity . those who assert only a plurality may be again subdistinguished into two subordinate divisions : ( such as held a plurality of worlds co●xis●ent ; among whom the most eminent was plutarch , who ( in lib. de oracul . defect . ) affirms , that to have many worlds at once , was consistent with the maje●●y of the divine nature , and consonant to human reason ; and ( in . placit . . ) earnestly labours to dissolve the contrary arguments of plato and aristotle for the unity of the world. no● were th●se all of one sect ; for some opinioned that there were many other worlds synchronical in the imaginary space , or on the outside of this : and others would admit of nothing , beyond trismegistus circle , or without the convex part of the empyraeum ; but conceived that every planet , nay , every star , contained in this , was an intire and distinct world. among these the principal were heraclides , the pythagoreans , and all the sectators of orphe●s : as they are enumerated by plutarch ( placit . . ) ( ) such as held a plurality of worlds , not coexistent or synchronical , but successive ▪ i. e. that this praesent world , phoenix-like , sprung up from the ruines of another praecedent ; and that the ashes of this s●all produce a third , the cinders of that a fourth , &c. of this perswasion were plato , heraclitus , and all the stoicks . the second species is made up of those , who dreamt of an infinity of worlds coexistent in an infinite space : and the chief seats in this classis belong to epicurus and metrodorus , upon the last of which this peremptory saying is commonly fathered ; 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . tam absurdum esse in universo infinito unum fieri mundum , quàm in magno agro unam nasci spicam . and below them shall sit anaximander , anaximenes , archelaus , xenophon , diogenes , leucippus , democritus , and zeno eleates , as may be collected from the records of stobaeus ( ecl. physic. l. . ) that epicurus was a grand patron of this error , is con●est by himself ( in epist. ad herodotum , apud laertium ) in these words : 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , caeterum in universitate , seu natura rerum , infiniti sunt mundi , alij quidem similes isti quem nos incolimus , alij verò dissimiles . the reasons , or rather the apparences of reason , which seduced the understandings of so many and great philosophers into a judgment , that there was an infinity of worlds ; are comprehended under these two. ( ) quod caussae sunt infinitae . nam si hic quidem mundus sit , fi●itus caussae verò , ex quibus est , fuêre omnino infinitae : necesse est mundi etiam sint infiniti . prorsus enim , ubi sunt caussae , effectus quoque ibi sunt . that worlds there are infinite in multitude , is manifest from hence , that there are infinite causes for worlds : for , since this world is finite , and the causes of which it was made , were infinite ; necessary it is that there be in●●nite worlds . insomuch as where are causes , there also must be effects . this epicurus more then intimated , when he argued thus : quippe atomi , cum sint infinitae , per insinitatem spatiorum feruntur ▪ & alibi aliae , ac pr●cu● ab hoc ad fabricationem mundorum infinitorum variè concurrunt . consule plutarc hum , ( . placit . . ) & lucretium . ( lib. . ) ( ) quod nulla sit specialis res , cui non suo sub genere sint singularia multa similia : that there is no one thing special , to which under that kind , many ●ingulars are not alike . upon this sand was it that plutarch erected his feeble structure of a plurality of worlds ; for ( in defect . oracul . ) he expresseth it at large , in these words , videmus naturam ipsis generibus , speciebusque , quasi quibusdam vasculis aut involucris seminum , res singulares continere . neque enim res ulla est numero una , cujus non sit communis ratio , neque ulla certam denominationem nanciscitur , quae singularis cum sit , non etiam com●unem qualitatem habeat . quare & hic mundus , ita singularitèr dicitur , ut communem tamen rationem , qualitatemque mundi obtineat : singularis autem conditionis sit , ex differentia ab alijs quae ejusdem generis sunt . et certè non unicus homo , non unicus equus , non unicum astrum , non unicus deus , non unicus daemon in rerum natura est : quid prohibit , quo ●inus plures , non unicum mundum natura contineat , &c. sect . ii. the redargution . that our redargution of this vain error may obtain the more both of perspicuity and credit , we are to advertise that the quaestion is not concerning the possibility , but the real or actual existence of an infinity of worlds . for , of the possibility , no man , imbued with the principles of physiology , or theology , can doubt . ( ) because , to the most profound and nice enquirers into that abstruse point , no argument , whether simple or complex , hath appeared weighty enough to disswade them from admitting an immense tohu , or infinite vacuum , without the extremities of this world. for , not a few , nor the least judicious part of even our christian doctors have asserted those extramundane spaces calling them imaginary ; because we can imagine the same dimensions of longitude , latitude , and profundity , to be in them , as are in those real spaces , wherein bodies are included in this world : and since all men , acknowledging the omnipotence of god , conclude , that he might , had he so pleased , have created this world larger and larger even to infinity ; necessary it is , that they also admit a larger and larger space or continent , for the reception of that enlarged world. which may with equal truth be accommodated also to an infinity of worlds ; insomuch as all , who acknowledge gods omnipotence , readily condescend , that he could , had it seemed good in the eye of his wisdom , have created more and more worlds , even to infinity : necessary it is , that they understand those worlds must be received in proportionate spaces , which ought to be over and above that space , which this world possesseth . for , whereas some have conceived ▪ that if god would create more worlds besides this , he must also create more spaces to contain them : undoubtedly they entangle themselves in that inextricable difficulty which is objected upon them , concerning the space interjected between any two worlds ; since that space may be brought under the laws of mathematical commensuration , and clearly explained by a greater or less distance . ( ) because , it is found no 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or desperate difficulty to defend a possible infinity of bodies . for the fathers of our church have delivered it as canonical , that god might have created any thing actually infinite not only in magnitude , but also in multitude . only they reserve the infinity of essence ; which since it can be competent to none but the divine essence , and comprehends all perfections whatever in a most transcendent or eminent manner : it is as absolutely impossible that any thing should be created actually infinite in essence , as that god should be created . which we conceive to be the ground of that truth ; that to imagine god to be able to create any thing equal to himself : is to suppose an imperfection in his nature . nor have they , without good cause , deserted the conduct of plato and aristotle , when they would seduce them into an opinion , that infinity is only potential , not actual , i. e. that nothing in rerum natura can be infinite in actu , but only in potentia ; insomuch as though a continuum may be either divided ▪ or augmented even to infinity : yet cannot that continuum either by division , or augmentation , ever become actually infinite . for , since even aristotle himself describes an infinite to be , non cujus extra nihil est , sed ex quo accipientibus semper aliquid accipiendum restat , that f●om which though nere so much be abstracted , yet still there shall more remain undeducted ; which is , in the sum or importance , to say that the essence of infinity is inexhauribility : it seems possible to admit not only many , but even infinite infinities in an infinite . thus we say , and truly , that in an infinite number are comprehended not only infinite unities , but also infinite binaries , infinite ternaries , infinite denaries , centenaries , &c. which is the reason of that axiom , that all the parts of an infinite are infinite . now though to be able , by perfect demonstration , to evince that there are no more worlds but this one , which we inhabit , is that of which to despair can be no dishonour to the most acute and mathematical wit in the world ; since none ought to doubt , but god might have created , and may yet at his pleasure create others innumerable , because neither can his infinite power ever be exhausted , nor that abyss of nothing , out of which the energie of his word instantly educed this world , not afford or space or matter for them : yet notwithstanding to affirm , that because 't is possible therefore there are many other worlds actually coexistent ; is a manifest inartificial argument , and a conclusion repugnant to all the inducements of persuasion . for , albeit we readily concede , that there is an infinite inanity or ultramundan space , yet can it not follow of necessity , that there are infinite atoms contained in that ultramundane space ; as democritus and epicurus praeposterously infer : insomuch as it sounds much more concordant to reason , that there are no more atoms , then those of which this single world was compacted . and when they argue thus ; since the vacuity or ultramundane space is infinite in magnitude or capacity , necessary it is that the abyss of atoms included therein be also infinite in extent ; because otherwise they could never have convened , and coalesced in that form , which the world now holds : we admit their induction for natural and legitimate , but detest their supposition as absurd and impossible . for , they take it for granted , that the chaos of atoms was not only eternal and increate , but also that it disposed , and compacted it self into that form , which constitutes the world , by the spontaneous motion inhaerent in atoms , and their fortuitous coalescenc● in such and such respective figures : when to a sober judgment it appears the highest impossibility imaginable , that either the chaos of atoms could be eternal , self-principate , or increate , or dispose and fix it self into so vast , so splendid , so symmetrical , so universally harmonical , or analogical a structure , as this of the world. for , as the disposition or dispensation of the chaos of atoms into so excellent a form , can be ascribed to no other cause , but an infinite wisdom : so neither can the production or creation of the same chaos be ascribed to any other cause , but an infinite power , as we have formerly demonstrated in our darkness of atheism , cap. . and therefore , since it is most probable that atoms were the materia prima , or material principle of the world ; as we shall clearly enunciate in a singular chapter subsequent : we may adventure to affirm , that god created exactly such a proportion of atoms , as might be sufficient to the making up of so vast a bulk , as this of the world , and that there remained no one superfluous . 't is unworthy a philosopher to acknowledge any superfluity in nature : and consequently a dangerous soloecism to say the god of nature knowing not how to proportion the quantity of his materials to the model or platform of his structure , created more atoms , then were necessary , and left an infinite residue to be perpetually hurried too and fro in the ultramundane space . if they shall urge upon us , that no man was privy to the councel of god at the creation , and consequently no can know , whether he created either more atoms then were requisite to the amassment of this world , or more worlds then this one : we may justly retort the argument upon them , and conclude , that since no man was privy to the councel of god , they have no reason to pretend to know , that god created either more matter , or more worlds ; and so the whole substance of the dispute must be reduced only to this : that they have no more reason for the support of their opinion of a plurality of worlds then we have fo● ours of the unity of the world ▪ nay the greatest weight of reason hangs on our end of the scale ; for , we ground our opinion upon that stable criterion , our sense , and asserting the singularity of the world , discourse of what our sight apprehends : but they found theirs upon the fragil reed of wild imagination , and affirming a plurality discourse of what neither the information of their sense , nor solid reason , nor judicious authority , hath learned them enough to warrant even conjecture . and , as to their second argument , viz. that there is in nature no one thing special , to which under the same kind , there are not many singulars alike : we answer , that all those singulars , which we observe to be multiplied under one and the same kind , are such which perish in the individual , and therefore cannot but be lost , if not conserved by the multitude of successors ; and not such as are not obnoxious to destruction by corruptibility , for they , constantly existing in the ●ndividual , need not multiplicity to their conservation . for which cause , one sun , and one moon are sufficient , and in al probability of this sort is the world ; for though it be conceived obnoxious to corruption , and shall once confess a period : yet is this no valid reason to justifie the necessity of a multitude of worlds , since the dissolution of the world shal be synchronical to the dissolution of nature , when sun , moon , and all other kinds of creatures , as well single as numerous shall be blended together in one common ruine ; and then the same infinite cause which hath destroyed them , can , with as much facility as he first created them , repair their ruines , educe them out of their second chaos , and redintegrate them into what form his wisdom shall design . nor is this opinion of a plurality of worlds only destitute of , but even è diametro repugnant to the principal inducements of belief . for , if we consider authority divine ; in moses inaestimable diary or narrative of the creation can be found no mention at all of a multitude of worlds , but on the contrary a positive assertion of one world ; and the express declarement of the manner how the fiat of omnipotence educed the several parts thereof successively out of the chaos , disposed them into subordinate piles , and endowed them with exquisite configurations respective to their distinct destinations , motions and uses : and in all the other books of sacred writ , whatever concerns the providence of god , the condition of man , the mysteries of his redemption , means of salvation , &c. doth more then intimate the singularity of the world ; nor is there any one word , if rightly interpreted , which can be produced as an excuse for the opposite error . if humane authority ; we may soon perceive , that those ancient philosophers , who have declared on our side , for the unity of the world , do very much exceed those pluralists nominated in our praecedent catalogue , both in number and dignity . for , thales , milesius , pythagoras , empedocles , ecphantus , parmenides , melissus , heraclitus , anaxagoras , plato , aristotle , zeno the sto●ck , attended on by all their sober disciples , have unanimously rejected and derided the conceit of many worlds , not only as vain and weak , but as extremly hypochondriack , and worthy a whole acre of hellebor . nor , indeed , are we persuaded , that so great wits as those of democritus and epicurus , did apprehend it as real ; but only imaginary , proposing it as a necessary hypothesis , whereon to erect their main physical pillar , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , vniversum esse ortus interitusque expers , that the universe is nonprincipiate and indissoluble . for , having mediated thus ; whatever is finite , is circumscribed by an external space , from which a cause may come and invading destroy it , and into which the matter thereof , a●ter the dissolution of its form , may be received : now this world , being finite , must be environed by a circumambient space , from which a cause may invade and destroy it ; and into which the matter thereof , after the dissolution of its form , may be received ; must of necessity therefore be dissoluble : they inferred , that , unless they would concede the universe to be dissoluble , which could never consist with their principles ▪ they must affirm it to be infinite , i. e. without which no space can be , from whence any cause might invade it , and into which the matter thereof after the destruction of its form , might be received : and thereupon concluded to suppose an infinity of worlds coexistent . which seems to be the reason also that induced epicurus and metrodorus to opinion , that the vniverse was not only 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 immutable , but also 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 immoveable : as may be collected from these words of plutarch quoted by eusebius ( . praepa . evang. . ) concerning metrodorus , is inter caetera non moveri universum dixit quoniam non est quò migrare possit ; nam si posset quidem , vel in plenum , vel in vacuum ; atqui universum continet quicquid hujusmodi est , quia si non contineret , minime foret vniversum . having thus amply refuted the dream of a plurality of worlds , both by detecting the exceeding invalidity of those two cardinal reasons , on which the authors and abettors of it had rashly fixed their assent ; and by convicting it of manifest repugnancy to authority divine and human : we may safely praesume , the understanding of our reader is sufficiently praepared to determine his judgment to an approbation of our thesis , the argument and title of this chapter , viz. that this adspectable world is the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 omne , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 vniversum , the all in rerum natura , the large magazine wherein all the wealth and treasure of nature is included ; and that there is nothing quantitative , but meerly local , beyond the convex extremity , or ( as arist. ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , substantiam quae est in ultima coeli conversione ; the outside of the empyraeum . thus much aristotle , though upon the conviction of other arguments , seems fully to have both understood and embraced , when in positive terms he affirmed , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 extra coelum neque est quicquam corpus , neque esse omninò potest ( de coelo l. . c. . ) as also whensoever he used those two words , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 & 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , vniversum & mundus , as perfect synonymaes , indifferently signifying one and the same thing : which was most frequent not only to him , but to plato also , and most of the most judicious sort of philosophers . if any curiosity be so immoderate , as to transgress the limits of this all , break out of trismegistus circle , and adventure into the imaginary abyss of nothing , vulgarly called the extramundan inanity ; in the infinity ( or , rather , indefinity ) of which many long-winged vvits have , like seel'd doves , flown to an absolute and total loss : the most promising remedy we can praescribe for the reclaiming of such wildness ; is to advertise ; that a serious diversion of thought to the speculation of any the most obvious and sensible of sublunary natures , will prove more advantagious to the acquisition of science , then the most acute metaphysical discourse , that can be hoped from the groveling and limited reason of man , concerning that impervestigable abstrusity ; of which the more is said , the less is understood ; and that the most inquisitive may find difficulties more then enough within the little vvorld of their own nature , not only to exercise , but empuzle them . to which may be annexed that judicious corrective of pliny , ( l. . nat. hist. c. . ) furor est , profectò furor est egredi ex hoc mundo , & tanquam interna ejus cuncta planè jam sint nota , ita scrutari extera . quasi verò mensuram ullius possit agere , qui sui nesciat : aut mens hominis videre , quae mundus ipse non capiat . and that facete scoff of the most ingenious mr. white ( in dialog . . de mundo . ) that the extramundan space is inhabited by chymaera's which there feed , and thrive to giants upon the dew of second intentions . chap. iii. corporiety and inanity . sect . i. the universe , or this adspectable world ( henceforth synonymaes ) doth , in the general , consist of only two parts , viz. something and nothing , or body and inanity . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , naturam rerum esse corpora & inane , was the fundamental position of epicurus ( apud plutarch . advers . colot . ) which his faithful disciple lucretius hath ingenuosly rendred in this distich : omnis , ut est igitur per se , natura duabus consistit rebus ; quae corpora sunt , & inane . the all of nature in two parts doth lye , that is , in bodies and inanity . concerning the nature or essence of a bodie , we find more then one notion among philosophers . ( ) some understanding the root of corporiety to be fixt in tangibility : as epicurus ( apud empericum advers . physic. ) saith , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : intell●gi corpus ex congerie figurae magnitudinis , resistentiae ( seu soliditatis ac impenetrabilitatis mutuae & gravitatis ; that by bodie is to be understood a congeries of figure , magnitude , resistence ( or solidity and impenetrability mutual ) and gravity . to which aristotle seems to allude ( in . physic. . ) where he saith of those who assert a vacuum , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 they conceive all bodies to be tangible : and lucretius , tangere enim & tangi sine corpore nulla potest res . here we are , per transennam , to hint ; that the authors of this notion , do not restrain the tangibility of bodies only to the sense of touching proper to animals ; but extend it to a more general importance , viz. the contact of two bodies reciprocally occurring each to other secundum superficies ; or what epicurus blended under the word , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , resistence mutual arising from impenetrability . ( ) others placing the essential propriety of a body in its extension into the three dimensions of longitude , latitude , and profundity . thus aristotle ( nat. auscult . . cap. . ) strictly enquiring into the quiddity of place , saith most profoundly ; 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : sanè dimensiones tres habet , longitudinem , latitudinem , & altitudinem , quibus omne corpus definitur . and thus des cartes ( princip . philos. part. . sect. . ) naturam materiae , sive corporis 〈◊〉 universum spectati , non consistere in eo quod sit res dura , vel ponderosa , vel colorata , vel aliquo alio modo sensus afficiens ; sed tantum in eo , quòd sit res extensa in longum latum & profundum : that the essence of matter , or a body considered in the general doth not consist in its hardness , weight , colour , or any other relation to the senses ; but only in its extension into the three dimensions . and ( ) others , by an excessive acuteness of wit , dividing the substance of a body from the quantity thereof , and distinguishing quantity from extension . of this immoderately subtle sect are all those , who conceived that most bodies might be so rarified and condensed , as that by rarefaction they may acquire more , and by condensation less of extension , then what they have before in their native dimensions . we say immoderately subtle , because whoever shall with due attention of mind profound the nature of rarefaction and condensation , must soon perceive ; that by those motions a body doth suffer no more then a meer mutation of figure , but its quantity admits of neither augmentation , nor diminution . so as those bodies may be said to be rare , betwixt whose parts many intervals or interstices , repleted with no bodies , are interspersed ; and those bodies affirmed to be dense , whose parts mutually approaching each to other , either diminish , or totally exclude all the intervals or intercedent distances . and when it eveneth , that the intervals betwixt the distant parts of a body , are totally excluded by the mutual access , convention and contact of its parts : that body must become so absolutely , or ( rather ) superlatively dense , as to imagine a possibility of greater density , is manifestly absurd . but yet notwithstanding , is not that body thus extremly dense , of less extension , then when having its parts more remote each from other , it possessed a larger space : in respect , that whatever of extension is found in the pores , or intervals made by the mutually receing parts , ought not to be ascribed to the body rarified , but to those small inanities that are intercepted among the dissociated particles . for instance ; when we observe a sponge dipt in liquor to become turgent and swell into a greater bulke ; we cannot justly conceive , that the sponge is made more extense in all its parts , then when it was dry or compressed : but only , that it hath its pores more dilated or open , and is therefore diffused through a greater space . but we may not digress into a full examen of the nature of rarefaction and condensation ; especially since the syntax of our physical speculations will lead us hereafter into a full and proper consideration thereof . of the nature of the other ingredient of the universe , inanity , there are several descriptions : ( ) epicurus names it 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , a region , or space , and a nature that cannot be touched : thereby intimating the direct contrariety betwixt the essential notion of corporiety and inanity ; which antithesis lucretius plainly expresseth in that verse , tactus coporibus cunctis intactus inani . ( ) cleomedes describes a vacuum to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ex sua natura incorporeum : adding for furrher explanation , siquidem est incorporeum , tactumque fugit , & neque figuram habet ullam , neque recipit , & neque patitur quicquam , neque agit , sed praebet solummodo liberum per seipsum corporibus motum ; it is incorporeal , because it cannot be touched , hath no figure of its own , nor is capable of any from others , neither suffers nor acts any thing , but only affords free space for the motion of other bodies through it . ( ) empiricus ( . advers physic. ) descanting upon epicurus description of inanity , saith ; natura eadem corpore destituta , appellatur inane ; occupata verò à corpore , locus dicitur , pervadentibus ipsam corporibus evadit regio : the same nature devoid of all body , is called a vacuum , if possessed by a body , 't is called a place , and when bodies pervade it , it becomes a region . and ( ) aristotle ( . physic. . ) defines a vacuum to be locus in quo nihil est , a place wherein no body is contained . now if we faithfully extract the importance of all these several descriptions of inanity , we shall find them to concurr in this common notion . as according to vulgar sense , a vessel is said to be empty , when it being capable of any , doth yet actually contain no body : so , ●ccording to the sense of physiology , that place , that region , or that space , which being capable of bodies , doth yet actually receive or contain none , is said to be a vacuum or emptiness . such would any vessel be if upon remove of that body , whereby its capacity was filled , no other body , the aer , nor ought else , should succeed to possess it : or such would that space be , which this book , that man , or any other body whatever doth now actually replenish , if after the remove of that tenent , neither the circumstant aer , nor ought else should succeed in possession , but it should be left on every side as it were limited by the same concave superficies of the circumambient , wherein the body , while a tenent , was circumscribed and included . of the existence of bodies in the world , no man can doubt , but he who dares indubitate the testimony of that first and grand criterion , sense , is regard that all natural concretions fall under the perception of some one of the senses : and to stagger the certitude of sense , is to cause an earthquake in the mind , and upon consequence to subvert the fundamentals of all physical science . nor is physiology , indeed , more then the larger descant of reason upon the short text of sense : or all our metaphysical speculations ( those only excluded , which concern the existence and attributes of the supreme being , the rational soul of man , and spirits : the cognition of the two former being desumed from proleptical or congenial impressions implantate in , or coessential to our mind ; and the belief of the last being founded upon revelation supernatural ) other then commentaries upon the hints given by some one of our external senses . which consideration caused epicurus to erect these two canons , as the base of logical judicature . ( ) opinio illa vera est , cui vel suffragatur , vel non refragatur sensus evidentia . ( ) opinio illa falsa est , cui vel refragatur vel non suffragatur sensus evidentia . that opinion is true , to which the evidence of sense doth either assent , or not dissent : and that false , to which the evidence of sense doth either not assent , or dissent . by the suffragation or assent of the evidence of sense , is meant an assurance that our apprehension or judgment of any object occuring to our sense , is exactly concordant to the reality thereof ; or , that the object is truly such , as we , upon the perception of it by our sense , did judge or opinion it to be . thus plato walking far off towards us , and we seeing him conjecture or opinion , as confidently as the great distance will admit , that it is plato , whom we see coming toward us : but when , by his nearer approach , the great impediment of certitude , distance is removed ; then doth the evidence of sense make an attestation or suffragation of the verity of our opinion , and confirm it to be plato , whom we saw . the non-refragation of sense , intends the consequution of some inevident thing , which we suppose or praesume to be , with reflection upon something sensibly evident , or apparent . as when we affirm that the●e is a vacuum ; which taken singly , or speculated ▪ in its own obscure nature , is wholly inevident , but may be demonstrated by another thing sufficiently evident , viz. motion : for if no vacuum , no motion ; since the body to be moved must want a place , wherein to be received , if all places be already full and crouded . hence comes it that the thing evident doth not refragari to the inevident . and thus the suffragation and nonrefragation of the evidence of sense , ought to be understood as one criterion , whereby any position may be evicted to be true . hither also may be referred that tetrastick of lucretius , ( lib. . ) corpus enim per se communis deliquat ess● sensus : quo nisi prima fides fundata valebit , haud erit , occultis de rebus , quò referentes confirmare animi quicquam ratione queamus . that bodies in the world existent are , our senses undeniably declare : whose certitude once quaestion'd ; we can find no judge to solve nice scruples of the mind . it remains therefore only that we prove ( ) that there is a vacuum in nature . ( ) that there is in the universe no third nature besides that of body and inanity . chap. iv. a vacuum in nature . sect . i. in order to our more prosperous evacuation of that epidemick opinion , vacuum non dari in rerum natura , that there is no vacuity or emptiness in the world ; it is very requisite , that we praemise , as a convenient praeparative , this short advertisement . among the speculations of many ancient physiologists , and especially of aristotle ( . physic. ) we find a vacuum distinguished into 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , & 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , secundum naturam , & eternaturam , a vacuum consistent with , and a vacuum totally repugnant to the fundamental constitutions of nature . according to which proper distinction , we may consider a vacuum ( ) as 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , disseminatum , interspersed , or of so large diffusion as variously to interrupt the continuity of the parts of the world. as 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , coacervatum , coacervate or separate from all parts of the world , such as the ultramundan space is conceived to be . now , if we respect the first consideration or acception of a vacuum , the quaestion must be , an detur vacuum disseminatum ? whether there be any small vacuity in nature , or more plainly , whether among the incontinued particles of bodies there be any minute insensible spaces intermixed , which are absolutely empty , or unpossessed by any thing whatever ? if the second ; then the doubt is to be stated thus : an detur vacuum intra mundanum coacervatum ? whether within the world ( for of the extramundane inanity , the difficulty is not great , as may be collected from the contents of our second chapter praecedent ) there can be any great or sensible vacuity , such as we may imagine possible , if many of the small or interspersed v●cuities should convene and remain in one entire coacervate inanity . concerning the first problem , we cannot state the doubt more intelligibly , then by proposing it under the analogy of this example . let a man intrude his hand into a heap of corn , and his hand shall possess a certain sensible space among the separated grains : his hand again withdrawn , that space doth not remain empty , but is immediately repossessed by the mutuall confluent grains , whose confluxibility , not impeded , causeth their instant convention . and yet betwixt the grains mutually convened there remaine many intercepted or interposed spaces or intervalls , unpossessed by them ; because the grains cannot touch each other so secundum totas superficies , according to all parts of their superficies , as to be contiguous in all points . exactly thus , when any body is intruded into aer , water , or any such rare and porous nature , betwixt whose incontinued parts there are many interstices variously disseminated , it doth possess a certain sensible space proportionate to its dimensions : and when that body is withdrawne , the space cannot remain empty , because the insensible or atomical particles of the aer , water , &c. agitated by their own native con●luxibility , instantly convene and repossess it . and yet , betwixt the convened particles , of which the aer , and water , and also all porous bodies are composed , there remain many empty spaces ( analogous to those intervalls betwixt the incontingent grains of corn ) so minute or exiguous , as to be below the perception and commensuration of sense . which is the very difficulty , concerning which there are so many controversies extant , as their very lecture would be a curse to the greatest patience . however , we conceive our selves sufficiently armed with arguments to become the assertors of a vacuum disseminatum ; or empty intervals betwixt the particles of rare , porous , or incontinued bodies . our first argument is that reason given for a vacuum by epicurus : 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , nisi esset inane , non haberent corpora neque uti essent , neque quo motus suos obirent , cùm moveri ea quidem manifestum sit : unless there were a vacuum , bodies could have neither where to consist , nor whither to be moved ; and manifest it is , that they are moved . which solid reason , though seemingly perspicuous , hath in it so many recesses of obscurity , as may not only excuse , but efflagitate a cursory paraphrase . first , we are to observe that , in the theory of epicurus , the notions of inanity and locality are one and the same essentially , but not respectively : i. e. that the same space when replenished with a body , is a place , but when devoid or destitute of any tenent whatever , then it is a vacuum . secondly , that aristotle did not sufficiently profound the quiddity of place , when he taught , that the concave superficies of the circumambient did constitute the essence thereof . for , when it is generally conceded that the locus must be adaequate to the locatum ; it is truly praesumed , that the internal superficies of the circumambient or place , ought to be adaequate to the external superficies of the locatum or placed ; but not to its profundity , or internal dimensions . and , since it is of the formal reason of place , that it be immoveable , or uncapable of translation ; for , otherwise any thing might , at one and the same time , be immote and yet change place : it is evident , that the superficies of the circumambient is not immoveable , since it may both be moved , the locatum remaining unmoved , and è contrà , persist unmoved , when the locatum is removed . and , therefore , the concave superficies of the circumambient may , indeed , obtain the reason of a vessel , but not of a place . and , upon consequence , we conclude , that the space comprehended within the superficies of the circumambient , is really and essentially what is to be understood by place since that space is adaequated perfectly to its locatum in all its internal dimensions , and is also truly immoveable ; in regard that upon the remove of the locatum , it remains fixt , unchanged , unmoved ; in the same state as before its occupation , it persevers after its desertion . and when the body removed possesseth a new space : the old space is instantly possessed by a new body . thirdly , that this argument desumed from the evidence of motion , was proposed by empiricus , ( advers . geometr . ) more syllogistically , thus , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . si motus est , inane est ; atqui motus est , est ergo inane . if there be motion , there must be ●●anity ; but motion there is , therefore there is a vacuum . that there is motion , is manifest from sense . and as for that memorable argument of zeno against motion , though we judge that he affected it more for the singularity , then solidity thereof , and only proposed it as a new paradox to gain some credit to scepticism , of which he was a fierce assertor ; and that no man did ever admit it to a competition with the authority of his sense : yet , since many have reputed it indissoluble , we conceive the solution thereof must become this place . motus non potest fieri per spatium quodvis , nisi pri●s mobile pertranseat minus , quam majus ; sed quamcunque assignes partem , alia est minor , & alia minor in infinitum : ergo non potest fieri motus , numquam enim incipiet . no motion can be made through any space whatever , unless the moveable first pass through a less , before a greater space ; but , what part of space soever you shall please to assign , still there will be another less part , and another less then that , and so up to infinity : therefore can there be no motion at all , since it can never begin at a space so little as that no less can remain . solution . the fallacie lyeth in the minor , which we concede to be true ratione mathematica , in the mathematical acceptation thereof ; and so no solution can be satisfactory to the argument , unless we admit an infinite divisibility in the parts of a continuum : but deny it ratione physica , in the proper physical acceptation , and so we may solve the riddle by proving the parts of a continuum not to be divisible ad infinitum , and motion is to be considered penes realem rerum existentiam . now , that space is divisible ad infinitum only extrinsecè and mathematicè , not physicè , may be thus evinc●● . if motion be divisible in infinitum , the parts of a slow motion will be as many as the parts of a swift motion : but 't is indubitate , that two parts of a swift motion are coexistent to one of a slow : therefore either that one part must be permanent , since it existeth in two times , or all motions are equall in velocity and tardity , which is repugnant to experience . and motion , space , and time , are perfectly analogous , i. e. proportional : for there is no part of motion , to which there may not be assigned a part of space and time fully respondent . besides , should we allow the argument to be too close for the teeth of reason ; yet no man can affirm it to be too hard for the sword of sense , and therefore it ought not to be reputed inextricable : since those objects which fall under the sincere judicature of the sense , need no other criterion to testifie their verity . upon which the judicious magnenus happily reflected ( p. . democriti reviviscent . ) when he layed down this for a firm principle : sensibilia per sensus sunt judicanda , nam illius potentiae est judicare de re , per quam res cognoscitur ; neque fides omnis sensibus deneganda . this short excursion ended , we revert to our fourth observable , viz. the consequution or inference of epicurus , in his argument for a vacuum : if no vacuum , no motion . which seems both natural and evident ; for what is full , cannot admit a second tenent : otherwise nothing could prohibit the synthesis or coexistence of many bodies in one and the same place ; which to imagine , is the extremest absurdity imaginable . for illustration , let us imagine , that the uuniverse ( having nothing of inanity interspersed among its parts ) is one continued mass of bodies so closely crouded , ramm'd , and wedged together , that it cannot receive any the least thing imaginable more : and keeping to this hypothesis , we shall soon deprehend , whether any one body among those many disposed within this compact or closely crouded mass may be removed out of its own to invade the place of another . certainly , if all places be full , it must extrude another body out of its place , or become joint-tenant with it and possess one and the same place . extrude a body out of its possession it cannot , because the extruded must want a room to be received into ; nor can the extruded dispossess a third , that third expel a fourth , that fourth eject a fifth , &c. since the difficulty sits equally heavy on all : and therefore , if the invaded doth not resign to the invading , there can be no beginning of motion , and consequently no one atome in the universe can be moved . and , as for its becoming synthetical or joint-tenant , that is manifestly impossible : because a collocat●on of two bodies in one and the same place , imports a reciprocal penetration of dimensions , then which nothing can be more repugnant to the tenor of nature : and therefore it remains , that every part of the universe would be so firmly bound up and compacted by other parts , that to move those cochles , snails , or insects , which are found in the ferruminated womb of rocks , and incorporated to the heart of flints , would be a far more modest attempt , then to move the least atome therein . nor can the dissenting evade the compulsion of this dilemma , by praetending , that in the universe are bodies of rare , porous , and fluxible constitutions , such as are more adapted to lococession , or giving place upon their invasion by other bodies , then are rocks or flints . because , unless their rarity , porosity , fluxibility , or yeeldingness be supposed to proceed from inanity disseminate ; or , that all the particles of those bodies are contiguous , or munually contingent secundum totas superficies ▪ doubtless , they must be so continued , as that it can make no difference , whether you call them bodies of flint or aer . for , neither shall the aer possess a place less absolutely then a flint : because how many particles soever of place you shall suppose , no one of them can remain unpossessed ; it being of the essence of place , that it be adaequate to its tenent in all its internal dimensions , i. e. in the number and proportion of particles : nor a flint more perfectly then aer , whose insensible particles are praesumed to be reciprocally contingent in all points , and so to exclude all interspersed inanity . we said , without inanity interspersed , there can be no beginning of motion . which to explain , let us suppose that a body , being to be moved through the aer , doth in the first degree of motion propel the contiguous aer , the space of a hairs bredth , now , the universe being absolutely full , that small space of a hairs bredth must be praepossessed , and so the body cannot be placed therein , untill it hath thence depelled the incumbent aer . nor can the contiguous aer possessing that space of a hairs bredth be depelled per latera to a place behind : because that place also is replete with aer . insomuch , therefore , as the body to be moved , cannot progress through so small a space , as that of an hairs bredth , because of the defect of place for the reception of the aer replenishing that space : it must of necessity remain bound up immoveably in that place , wherein it was first situate . but if we conceive the aer to have small inane vacuolas , or spaces ( holding an analogy to those spaces interceding betwixt the grains of a heap of corn or sand ) variously interposed among its minute insensible particles : then may we also conceive , how the motion of a body through the aer is both begun and continued : viz. that the body moved , doth by its superfice protrude the particles of the contiguous aer , those protruded particles being received into the adjacent empty interstices , press upon the next vicine particles of aer , and likewise protrude them , which received also into other adjacent empty spaces become contiguous to , and urgent upon other next particles of aer , and so forward untill , upon the successive continuation of the compression by protrusion , and the consequent dereliction of a place behind , the lateral particles of the aer , compressed by the anterior parts dissilient , are effused into it : and so , how much of aer is compressed and impelled forward , so much recurrs backward per latera , and is dilated . the same also may be accommodated to the lococession of the parts of water ; allowing it this praerogative , that being propelled by a body movent , it doth by its particles more easily propel the contiguous particles of the aer , then it s own ; because the empty minute spaces of the aer incumbent upon the water , are larger , which may be the reason , why water propelled forwards , becomes tumid and swelleth somewhat upwards in its superfice , and is depressed proportionately backward . now according to this theory , ought we to understand the reason of epicurus for a vacuum , desumed from the necessity of motion . sect . ii. as the nature of motion considered in the general , hath afforded us our first argument , for the comprobation of a vacuity disseminate : so likewise doth the nature of rarefaction and condensation , which is a species of local motion , speculated in particular , readily furnish us with a second . examine we therefore , with requisite scrutiny , some of the most eminent apparences belonging to the expansion and compression of aer and water : that so we may explore , whether they can be salved more fully by our hypothesis of a disseminate vacuity , then by any other , relating to an universal plenitude . take we a pneumatique or wind-gun , and let that part of the tube , wherein the aer to be compressed is included , be four inches long ( the diameter of the bore or cavity being supposed proportionate : ) now if among the particles of that aer contained in the four inched space of the tube , there be no empty intervals , or minute inanities ; then of necessity must the mass of aer included be exactly adaequate to the capacity or space of four inches , so as there cannot be the least particle of place , wherein is not a particle of aer aequal in dimensions to it , i. e. the number of the particles of aer is equal to the number of the particles of the cavity . suppose we then the number of particles common to both , to be . this done , let the aer , by the rammer artificially intruded , be compressed to the half of the space ( not that the compression may not exceed that rate , for mersennus ( in praef . ad hydraulicam pneumaticam artem . ) hath by a most ingenious demonstration taught , that aer is capable of compression even to the tenth part of that space , which it possessed in the natural disposition , or open order of its insensible particles : ) and then we demand , how that half space , viz. two inches , can receive the double proportion of aer , since the particles of that half space are but . either we must grant that , before compression , each single particle of aer possessed two particles of space , which is manifestly absurd : or , that after compression , each single particle of space doth contain two of aer , which is also absurd , since two bodies cannot at once possess the same place : or else , that there were various intervals inane disseminate among the particles of aer , and then solve the phaenomenon thus . as the grains of corn , or granules of sand , being powred into a vessel up to the brim , seem wholly to fill it ▪ and yet by succussion of the vessel , or depression of the grains upon the imposition of a great weight , may be reduced into a far less space ; because from a more la● and rare , they are brought to a more close and constipate congeries , or because they are reduced from an open , to a close order , their points and sides being more adapted for reciprocal contact quoad totas superficies , nor leaving such large intervals betwixt them as before succussion or depression . so likewise are the particles of aer included in the four-inched space of the tube , by compression or coangustation reduced downe to the impletion of onely the hal● of that space ; because from a more lax or rare contexture they are contracted into a more dense or close , their angles and sid●● being by that force more disposed for reciprocal contingence , and leaving less intervals , or empty spaces betwixt them then before . our second experiment is that familiar one of an aeolipile which having one half of its concavity replete with water , and the other with aer , and placed in a right position near the fire : if you will not allow any of ●he spaces within it to be empty , pray , when the water by incalescen●● rarefied into vapours , issues out with thundering impetuosity through the slender perforation or exile outlet of its rostrum , successively for many hours together , how can the same capacity still remain full ? for , if before incalefaction the particles of water and aer were equal to the number of the particles of space contained therein ▪ pray , when so many parts both of water and aer , consociated in the form of a vapour , are evacuated through the orifice , must not each of their remaining parts possess more parts of the capacity , and so be in many places at once ? if not so , were there not , before the incalescence , many parts of water and aer crouded into one and the same part of space , and so a manifest penetration of real dimensions ? remains it not therefore more verisimilous , that , as an heap of dust dispersed by the w●nd , is rarefied into a kind of cloud and possesseth a far larger space then before its dispersion ; because the disgregated granules of dust intercept wider spaces of the ambient aer : so the remaining parts of water and aer in the cavity of the aeolipile possess all those spaces left by the exhaled parts ; because they intercept more ample empty spaces , being disposed into a more lax and open contexture . and that this is caused by the particles of fire , which intruding into , and with rapid impetuosity agitated every way betwixt the sides of the aeolipile , suffer not the parts of aer and water to quiesce , but disperse and impel them variously : so that the whole space seems constantly full by reason of the rapidity of the motion . the third mechanick experiment , which may justifie the submission of our assent to this paradox , is this . having praepared a short tapor of wax and sulphur grosly powdered , light and suspend it by a small wier in a glass vial of proportionate reception , wherein is clean fountain water sufficient to possess a fifth part , or thereabout , of its capacity : and then with a cork fitted exactly to the orifice , stop the mouth of the vial so closely , that the eruption of the most subtle atom may be prevented . on this you shall perceive the flame and fume of the sulphur and wax instantly to diffuse and in a manner totally possess the room of the aer , and so the fire to be extinguished : yet not that there doth succeed either any diminution of the aer , since that is imprisoned , and all possibility of evasion praecluded ; or any ascent of the water , by an obscure motion in vulgar physiology called suction , since here is required no suction to supply a vacuity upon the destitution of aer . but if you open the orifice , and enlarge the imprisoned aer , you shall then indeed manifestly observe a kind of obscure suction , and thereupon a gradual ascention of the water : not that the flame doth immediately elevate the water , as well because it is extinct , and the water doth continue elevated for many hours after its extinction , as that , if the flame were continued , can it be imagined that it would with so much tenacity adhaere to the tapor , as is requisite to the elevation of so great a weight of water ; but rather , that upon the coangustation or compression of the aer reduced to a very close order in the mutual contact of its insensible particles , the empty spaces formerly intercepted betwixt them being replenished with the exhalations of the tapor ; when the orifice is deobturated , there sensibly succeeds a gradual expiration of the atoms of fire , as the most agile , volatile and prepared for motion , and then the aer , impelled by its own native fluxibility , re-expands or dilates it self by degrees . but since the narrowness of the evaporatory , or ori●ice prohibits the so speedy reflexion or return of the compressed particles of the aer to their naturall contexture or open order , as the renitency of their fluxibility requireth , so long as there remain any of the atoms of fire in possession of their vacuities , as long continues the reexpansion of the aer ; and that reexpansion pressing upon the sides of the water , causeth it to ascend , and continue elevated . and no longer , for so soon as the aer is returned to its native contexture , the water by degrees subsideth to the bottom , as before the accension of the tapor : and so that motion commonly called a suction in avoidance of vacuity , is more properly a protrusion , caused by the expanding particles of aer compressed . if any praecipitous curiosity shall recur to this sanctuary , that in the substance of the aer is contained aliquid combustibile , some combustible matter , which the hungry activity of the flame of the tapor doth prey upon , consume and adnihilate : he runs upon a double absurdity ; ( ) that in nature is a substance , which upon the accidental admotion of fire , is subject to absolute adnihilation , which to suppose , smels of so great a wildness of imagination as must justifie their sentence , who shall consign the author of it to seven years diet on the roots of white hellebor , nor durst any man but that elias artium helmont , adventure on the publique patronage of it . ( ) that the aer is the pabulum , or fewel of fire : which though no private opinion , but passant even among the otherwise venerable sectators of aristotle ( who unjustly refer the extinction of flame imprisoned , to the defection of aer : as intimating that the destruction of fire , like that of animals doth proceed from the destitution of aliment ) is yet openly inconsistent to reason and experiment . to reason , because the aer , considered sincerely as aer , without the admixture of vapours and exhalations , is a pure , simple and homogeneous substance , whose parts are consimilar : not a composition of heterogeneous and dissimilar , whereof some should submit to the consumptive energie of fire , and other some ( of the invincible temper of salamandes wool , or muscovy glass , ) con●erve their originary integrity inviolable in the highest fury of the flames . again , themselves unanimously approve that definition of galen lib. . de element . cap. . ) elementa sunt natura prima & simplicissima corpora , quaeque in alia non amplius dissolvi queant : that it is one of the essential proprieties of an element as to be ingenerable , so also indissoluble : and as unanimously constitute the aer to be an element . to experiment , because had the fire found ( and yet it is exceedingly inquisitive , especially when directed by appetite , according to their supposition ) any part of the aer i●flamable ; the whole element of aer had been long since kindled into an unive●sal and inextinguable conflagration , upon the accension of the first focal ●●re : nor could a flash of lightning or gunpowder ▪ be so soon extinct if the flame found any maintenance or sustentaculum in the aer , but would enlarge it self into a combustion more prodigious and destructive then that caused by the wild ambition of phaeton . most true it is , that fire deprived of aer , doth suffer immediate extinction : yet not in respect of aliment denyed ( for nutrition and vitality are ever convertible ) but of the want of room sufficient to contain its igneous and fuliginous exhalations , which therefore recoiling back upon the flame , coarctate , suffocate , and so extinguish it . for upon the excessive and impetuous suddain afflation of aer , flame doth instantly perish , though not imprisoned in a glass : the cause is , that the flame , not with tenacity sufficient adhaering to the body of the tapor , or lamp , is easily blown off , and being thus dislodged hath no longer subsistence in the aer . and heat , beating upon the outside or convex part of a glass , seems sensibly to dilate the aer imprisoned within ; as is manifest upon the testimonie of all thermometres , or weather-glasses , those only which contain chrysulca , or aqua fortis in stead of water , at least if the experiment be true , excepted : but fire in the concave or inside of the glass violently compresseth the aer , by reason of its fuliginous emissions , which wanting vacuities enough in the aer for their reception , recoil and suffocate the fire . the fourth , this . being in an intense frost at droitwich in worcestershire , and feeding my curiosity with enquiring into the mechanick operations of the wallers ( so the salt-boylers are there called ) i occasionally took notice of yce , of considerable thickness , in a hole of the earth , at the mouth of a furnace very great and charged with a reverberatory fire , or ignis rotae . consulting with my phylosophy , how so firm a congelation of water could be made by cold at the very nose of so great a fire ; i could light on no determination , wherein my reason thought it safe to acquiesce , but this . that the ambient aer , surcharged with too great a cloud of exhalations from the fire , was forced to a violent recession or retreat , and a fresh supply of aer as violently came on to give place to the receding , and maintain the reception of fresh exhalations ; and so a third , fourth and continued relief succeeded : and that by this continued and impetuous afflux , or stream of new aer , loaden with cold atoms , the activity of the cold could not but be by so much the more intense at the mouth of the furnace , then abroad in the open aer , by how much the more violent the stream of cold aer was there then elsewhere . to complete and assure the experiment , i caused two dishes , of equal capacity , to be filled with river water ; placed one at the mouth of the furnace , the other sub dio : and found that near the furnace so nimbly creamed over with yce , as if that visibly-freezing tramontane wind , which the italian calls chirocco , had blown there , and much sooner perfectly frozen then the other . and this i conceive to be also the reason of that impetuous suction of a stream of aer , and with it other light and spongy bodies , through the holes or pipes made in many chimneys , to praevent the repercursion of smoke . from these observations equitably perpended and collated , our meditations adventured to infer ( ) that the aer ; as to its principal and most universal destination was created to be the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or common receptary of exhalations : and that for the satisfaction of this end , it doth of necessity contain a vacuum desseminatum in those minute and insensible incontiguities or intervals betwixt its atomical particles ; since nature never knew such gross improvidence , as to ordain an end , without the codestination of the means requisite to that end. to praevent the danger of misconstruction in this particular , we find our selves obliged to in●imate ; that in our assignation of this function or action to the aer , we do not restrain the aer to this use alone : since ignorance it self cannot but observe it necessarily inservient to the conservation of animals endowed with the organs of respiration , to the transvection of light , the convoy of odours , sounds , and all species and aporrhaeas , &c. but that , in allusion to that distinction of anatomists betwixt the action and use of a part , we intend ; that the grand and most general action of the aer , is the reception or entertainment of vapours and exhalations emitted from bodies situate in or near the terraqueous globe . and in this acception , allowing the aer to be constituted the general host to admit ; we insinuate that it hath rooms wherein to lodge the arriving exhalations : insomuch as the necessity of the one , doth import as absolute a necessity of the other ; the existence of the final ever attesting the existence of the conductive , or mediatory cause . ( ) that , though the aer be variously interspersed with empty interstices , or minute incontiguities , for the reception of exhalations : yet doth it receive them at a just rate , tax , or determinate proportion , conform to its own capacity , or extensibility ; which cannot without reluctancy and violence be exceeded . for when the vacuities , or holds have taken in their just portage , and equal fraught , the compressed aer hoyseth sail , bears off , and surrenders the scene to the next advenient or vicine aer , which acteth the like part successively to the continuation of the motion . this may be exemplified in the experiment of the furnace and chimneys newly mentioned , but more manifestly in that of the sulphurate tapor in the vial : where the aer , being overburthened with too great a conflux of fuliginous exhalations , and its recession impeded by the stopping of the vial , it immediately recontracteth it self , and in that renitency extinguisheth by suffocation the rude flame , which oppressed it with too copious an afflux . as also in those of canons and mines ; which could not produce such portentous effects , as are dayly observed in wars , if it were not in this respect , that the receptaries in the aer suffer a ra●k or extension beyond their due capacities . for , when the powder fired in them is , in the smallest subdivision of time , so much subtiliated , as to yeeld a flame ( according to the compute of m●rsennus ) of parts larger in extension , then it self , while its atoms remained in the close order and compact form of powder ; and the aer ▪ by reason of its imprisonment , is not able to recede , and bear off so speedily , as the velocity of the motion requires : for avoidance of a mutual penetration of dimensions among the minute particles of the fire , smoke , and its own , it makes an eruption with so prodigious an impetuosity , as to shatter and evert all solid bodies situate within the orb of impediment . for the further confirmation of our first thesis , viz. that the aer is interspersed with various porosities , or vacuities , by reason of the incontiguity of its insensible particles ; and that these serve to the reception of all exhalations : we shall superadd these two considerable arguments . ( ) if this vacuum disseminatum of the aer be submoved , and an absolute plenitude in the universe from a continuity of all its parts supposed ; then must every the smallest motion , with dangerous violence run through the whole engine of the world , by reason of that continuity . ( ) if the aer were not endowed with such porosities , other bodies could never suffer the dilatation or rarefaction of themselves ; since , upon the subtiliation or dilatation of their minute particles , i e. the remove of their atoms from a close to an open contexture , they possess times larger capacities : and so there would be no room to entertain the continual effluviums , expiring from all bodies passing their natural vicissitudes and degenerations . sect . iii. to these four eminent experiments , we might have annexed others numerous enough to have swelled this chapter into a volume ; but conceiving them satisfactory to any moderate curiosity , and that it can be no difficulty to a physiological meditation , to salve any apparence of the same nature , by this hypothesis of a vacuum disseminatum in the aer , as the caussa sine qua non of its rarefaction and condensation : we judged it more necessary to address to the discharge of the residue of our duty , vi● . to praesent it as verisimilous ; that in the water also are variously dispersed the like vacuola , or empty spaces , such as we have not unfitly compared to those 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or intervals betwixt the granules of sand in a heap , in those parts where their superficies are not contiguous , in respect of the ineptitude of their figures for mutual contact in all points . and this seems to us so illustrious a verity , as to require neither more attestation , nor explanation , then what this one singular experiment imports . 't is generally known , that water doth not dissolve salt in an indefinite quantity , but ad certam taxam , to a certain determinate proportion ; so as being once sated with the tincture thereof , it leaves the overplus entire and undissolved . after a long and anxious scrutiny for a full solution of this phaenomenon , our thoughts happily fixed upon this : that , the salt being in dissolution reduced ( analysi ret . ograda ) into its most minute or atomical particles , there ought to be in the water consimilar or adaequate spaces for their reception ; and that those spaces being once replenished , the dissolution ( because the reception ) ceaseth . not unlike to a full stomach , which eructates and disgorges all meats and drinks superingested : or full vessels , which admit no liquor affused above their brim . hereupon , having first reflected upon this , that the atomical particles of common salt are cubical ; and thereupon inferred , that , since the locus must be perfectly adaequate to the locatum , they could only fill those empty spaces in the water , which were also cubical : we concluded it probable , that in the water there ought to be other empty spaces octohedrical , sexangular , sphaerical , and of other figures , which might receive the minute particles of other salts , such as alum , sal ammoniac , halinitre , sugar , &c. after their dissolution in the same water . nor did experiment falsifie our conjecture . for , injecting alum parcel after parcel , for many dayes together , into a vessel of water formerly sated with the tincture of common salt ; we then , not without a pleasant admiration , observed that the water dissolved the alum as speedily , and in as great quantity , as if it altogether wanted the tincture of salt ; nor that alone , for it likewise dissolved no small quantities of other salts also . which is no obscure nor contemptible evidence , that water doth contain various insensible loculaments , chambers , or receptaries of different figures : and that this variety of those figures doth accommodate it to extract the tinctures of several bodies in●ected and infused therein ▪ so as it is exceedingly difficult , to evince by experiment that any liquor is so sated with precedent tinctures , as no● to be capable of others also : especially while we cannot arrive at the exact knowledge of the figure of the atomical particles of the body to be infused , nor of the figures of those minute spaces in the liquor , which remain unpossessed by the former dissolutions . upon which reason , we are bold to suspect the truth of the lord s. albans assertion ; centur. nat. hist. ) that by repeating the infusion of rhubarb several times , letting each dose thereof remain in maceration but a small time ( in regard to the fineness and volatility of its spirits , or emanations ) a medicament may be made as strongly catharctical or purgative , as a simple infusion of s●amony in the like weight . for ( ) when the empty spaces in the menstruum , or liquor , which respond in figure to the figure of the atomical particles of the rhubarb , are replenished with its tincture ; they can admit no greater fraught , but the imbibition of virtue ceaseth : and that two or three infusions , at most , suffice to the repletion of those respective spaces , may be collected from hence , that the rhubarb of the fourth infusion loseth nothing of its purgative faculty thereby , but being taken out and singly infused in a proportionate quantity of the like liquor , it worketh as effectually as if it had never been infused before . ( ) experience testi●ieth the contrary , viz. that a drachm of scamony singly infused in an ounce and half of white wine , doth operate ( caeteris paribus ) by parts of , more smartly then drachms of rhubarb successively infused in the like quantity of the same or any other convenient liquor . here also is the most probable cause , why two drachms of antimony crude , or crocus metallorum , give as powerful a vomitory impraegnation to a pint of sa●● , or white wine , as two ounces : viz. because the menstruum hath no more vacuities of the same figure with the atomical ef●luviums of the antimony , then what suffice to the imbibition or admission of the two drachms . for the certitude of this , we appeal to the experience of a lady in cheshire , who seduced by an irregular charity , and an opinion of her own skill , doth praetend to the cure of the sick , and to that purpose praepares her catholique vomitory , consisting of four drachms and an half of crude stibium infused all night in or ounces of white wine , and usually gives it ( without respect to the individual temperament of the assument for one dose to the sick ▪ and yet , as our selves have more then once observed , the infusion doth work with no greater violence , in some persons , then as much of our common emetique infusion praescribed in the reformed dispensatory of our venerable college . nay more then this , our selves have often reduced the dose of the same emetique infusion down only to scruples , and yet found its operation come not much short of the usual dose of an ounce . hence also may be desumed a satisfactory reason for the impraegnation of one and the same menstruum with various tinctures : for example , why an infusion of rhubarb , sated with its tincture , doth afterward extract the tinctures of agarick , senna , the cordial flowers , cremor tartari , &c. injected according to the praescript of the judicious physician , in order to his confection of a compound medicament requisite to the satisfaction of a complex scope or intention . sect . iv. a third argument , for the comprobation of a vacuum disseminatum , may be adferred from the cause of the difference of bodies in the degrees of gravity , respective to their density or rarity , ( i. e. ) according to the greater or less inane spaces interspersed among their insensible particles . and a fourth likewise from the reason of the calefaction of bodies by the subingress or penetration of the atoms of fire into the empty intervals variously disseminate among their minute particles . but , in respect that we conceive our thesis sufficiently evinced by the praecedent reasons ; and that the consideration of the causes of gravity and calefaction , doth , according to the propriety of method , belong to our succeeding theory of qualities : we may not in this place insist upon them . and as for those many experiments of water-hour-glasses , syringes , glass fountains , cuppinglasses , &c. by the inconvincible assertors of the peripatetick physiology commonly objected to a vacuity : we may expede them altogether in a word . we confess , those experiments do , indeed , demonstrate that nature doth abhort a vacuum coacervatum ; as an heap of sand abhors to admit an empty cavity great as a mans hand extracted from it : but not that it doth abhor that vacuum disseminatum , of which we have discoursed ; nay , they rather demonstrate that nature cannot well consist without these small empty spaces interspersed among the insensible particles of bodies , as an heap of sand cannot consist without those small interstices betwixt its granules , whose figures prohibit their mutual contact in all points . so that our assertion ought not to be condemned as a kaenodox inconsistent to the laws of nature , while it imports no more then this ; that , as the granules of a heap of sand mutually flow together to replenish that great cavity , which the hand of a man by intrusion had made ▪ and by extraction left , by reason of the confluxibility of their nature : so also do the granules , or atomical particles of aer , water , and other bodies of that rare condition , flow together , by reason of the fluidity or confluxibility of their nature , to praevent the creation and remanence of any considerable , or coacervate vacuum betwixt them . to instance in one of the experiments objected . water doth not distil from the upper into the lower part of a clepsydra , or water-hour-glass , so long as the orifice above remains stopped ; because all places both above and below are ful , nor can it descend until , upon unstopping the hole , the aer below can give place , as being then admitted to succeed into the room of the lateral aer , which also succeeds into the room of that which en●ered above at the orifice as that succeeds into the room of the water descending by drops , and so the motion is made by succession , and continued by a kind of circulation . the same also may be accommodated to those vessels , which gardners use for the irrigation of their plants , by opening the hole in the upper part thereof , making the water issue forth below in artificial rain . it only remains , therefore , that we endeavour to solve that giant difficulty , proposed in defiance of our vacuum disseminatum , by the mighty mersennus ( in phaenomen . pneumatic . propos . . ) thus . quomodo vacuola , solitò majora in rarefactione , desinant , aut minora facta in condensatione crescant iterum : quaenam enim elateria cogunt aerem ad sui restitutionem ? how do those vacuities minute in the aer , when enlarged by rarefaction , recover their primitive exility ; and when diminished by condensation , re-expand themselves to their former dimensions : what elaters or springs are in the aer , which may cause its suddain restitution to its natural constitution of insensible particles ? we answer ; that , as it is the most catholique law of nature , for every thing , so much as in it lies , to endeavour the conservation of its originary state ; so , in particular , it is the essential quality of the aer , that its minute particles conserve their natural contexture , and when forced in rarefaction to a more open order , or in condensation to a more close order , immediately upon the cessation of that expanding , or contracting violence , to reflect or restore themselves to their due and natural contexture . nor need the aer have any principle or efficient of this reflection , other then the fluidity or confluxibility of its atomical parts : the essence or quiddity of which quality , we must reserve for its proper place , in our ensuing theory of qualities . chap. v. a vacuum praeternatural . sect . i. besides a natural , or disseminate vacuity frequently intercepted betwixt the incontiguous particles of bodies ( the argument of our immediately precedent chapter ) not a few of the highest form in the school of democritus have adventured to affirm not only the possibility , but frequent introduction of a praeternatural or coacervate inanity : such as may familiarly be conceived , if we imagine many of those minute inane spaces congregated into one sensible void space . to assist this paradox , the autoptical testimony of many experiments hath been pleaded ; especially of that glass fountain invented by hero ( praef . in spirit . ) and fully described by the learned and industrious turnebus ( in lib. de calore ) and of that brass cylindre , whose concave carries an embolus , or sucker of wood , concerning which the subtle galilaeo hath no sparing discourse in the first of his dialogues : but , above all , of that most eminent and generally ventilated one of a glass cylindre , or tube filled with quicksilver , and inverted ; concerning which not long after the invention thereof by that worthy geometrician , torricellius , at florence , have many excellent physicomathematical discourses been written by monsieur petit , dr. paschal mersenn●s , gassendus , stephanus natalis . who , being all french , seemed unanimously to catch at the experiment , as a welcom opportunity to challenge all the wits of europe to an aemulous combat for the honour of perspicacity . now albeit we are not yet fully convinced ▪ that the chief phaenomenon in this illustrious experiment doth clearly demonstrate the existence of a coacervate vacuity , such as is thereupon by many conce●ed , and with all possible subtlety defended by that miracle of natural science , the incomparable mersennus ( in reflexionib . physicomathemat . ) yet , insomuch as it affords occasion of many rare and sublime speculations , whereof some cannot be solved either so fully , or perspicuously by any hypothesis , as that of a vacuum disseminatum among the insensible particles of aer and water ; and most promise the pleasure of novelty , if not the profit of satisfaction to the worthy considerer ; we judge it no unpardonable digression , here to present to our judicious reader , a faithful transcript of the experiment , together with the most rational solutions of all the admirable apparences observed therein , first by torricellius and the rest beyond sea , and since more then once by our selves . the experiment . having praepared a glass tube ( whose longitude is feet , and the diameter of its concavity equal to that of a mans middle finger ) and stopped up one of its extremities , or ends , with a seal hermetical : fill it with quicksilver , and stop the other extreme with your middle finger . then , ha●ing with a most slow and gentle motion ( lest otherwise the great weight of the quicksilver break it ) inverted the tube , immerge the extreme stopt by your finger into a vessel filled with equal parts of quicksilver and water , not withdrawing your finger untill the end of the tube be at least or inches deep in the subjacent quicksilver : for , so you praevent all insinuation or intrusion of aer . this done , and the tube fixed in an erect or perpendicular position ; upon the subduction of your finger from the lower orifice , you may observe part of the quicksilver contained in the tube to descend speedily into the restagnant or subjacent quicksilver , leaving a certain space in the superior part of the tube , according to apparence at least , absolutely void or empty : and part thereof ( after some reciprocations or vibrations ) to remain still in the tube , and possess its cavity to a certain proportion , or altitude of digits , or feet , digits and an half ( proximè ) constantly . further , if you recline , with a gentle motion also , the upper extreme of the tube , untill the lower , formerly immersed in the quicksilver , arise up into the region of the water incumbent on the surface of the quicksilver : you may perceive the quicksilver remaining in the tube to ascend by sensible degrees up to the superior extreme thereof , together with part of the water ; both those liquors to be confounded together ; and , at length , the quicksilver wholly to distill down in parcels , surrendring the cavity of the tube to the possession of the water . likewise , if you recline the superior extreme of the tube , untill its altitude respond to that of digits , still retaining the opposite extreme in the region of the subjacent quicksilver in the vessel : then will the quicksilver be sensibly impelled up again into the tube , untill that space formerly vacated be replenished . finally , if , when t●e quicksilver hath fallen down to the altitude of digits , the tube be suddainly educed out of the subjacent quicksilver and water , so as to arrive at the confines of the aer ; then doth the aer rush into the tube below , with such impetuosity , as to elevate the quicksilver and water contained in the tube , to the top ; nay , to blow up the sealed end thereof , and drive out the liquors or feet perpendicular up in the aer ; not without some terror , though not much danger to the experimentator , especially if he do not expect it . now though it be here praescribed , that the tube ought to be feet in length , and the amplitude of its cavity equal to that of an ordinary mans finger : yet is neither of these necessary ; for , whatever be the longitude , and whatever the amplitude of the tube , still doth the quicksilver , after various reciprocations , acquiesce and subsist at the same standard of digits ; as dr paschal junior found by experience in his tube feet long , which he bound to a spear of the same length , so to prevent the fraction thereof , when it was erected perpendicularly , replete with quicksilver , in libro cui titulus , experiences novelles touchant le vuide . ) among those many ( natalis reckons up no less then ) stupendious magnalities , or rare effects , which this eminent experiment exhibits to observation ; the least whereof seems to require a second oedipus more perspicacious then the first , for the accommodation thereof though but to plausible and verisimilous causes , and might had aristotle known it , have been reputed the ground of his despair , with more credit then that petty problem of the frequent and irregular reciprocation of euripus : we have selected only six , as the most considerable , and such whose solution may serve as a bright tapor to illuminate the reason of the curious , who desire to look into the dark and abstruce dihoties of the rest . sect . ii. the first capital difficulty . whether that space in the tube , betwixt the upper extreme thereof and the quicksilver delapsed to the altitude only of digits , be really an entire and absolute vacuity ? concerning this , some there are who confidently affirm the space between the superfice of the quicksilver defluxed and the superior extreme of the tube , to be an absolute coacervate vacuitie : such as may be conceived , if we imagine some certain space in the world to be , by divine or miraculous means , so exhausted of all matter or body , as to prohibit any corporeal transflux through the same . and the reasons , upon which they erect their opinion , are these subsequent . this space , if possessed by any tenent , must be replenished either with common aer , or with a more pure and subtle substance called aether , which some have imagined to be the universal caement or common elater , by which a general continuity is maintained through all parts of the universe , and by which any vacuity is praevented : or by some exhalation from the mass of quicksilver included in the tube . first , that it is not possessed by aer , is manifest from several strong and convincing reasons . ( ) because the inferior end of the tube , d , is so immersed into the subjacent mass of quicksilver below the line ef , that no particle of aer can enter thereat . ( ) because , if there were aer in the tube filling the deserted space ck , then would not the circumambient or extrinsecal aer , when the tube is educed out of the restagnant quicksilver , and water , rush in with that violence , as to elevate the remainder of the quicksilver in the tube , from k to d , up to the top c , and break it open , as is observed : in regard , that could not happen without a penetration of bodies . so that , if we suppose any portion of aer to have slipped into the tube below , at the subduction of the finger that closed the orifice : then would not the mercury reascending ( upon the inclination of the tube down to the horizontal line km , ) rise up quite to the top c , but subsist at op . but the contrary is found upon the experiment . ( ) if any portion of aer chance to intrude into the cavity of the tube , which may come to pass either if , when the superior orifice of the tube is inverted , it be not exactly obturated by the finger of the experimentator ; or , if at the extraction of his finger the lower e●treme be not immersed deep enough in the subjacent mercury , to prevent the subingress of some aer ; or , if the orifice of the tube educed out of the region of the subjacent mercury and water ▪ be not wholly deobturated at once , but so as there is only some slender inlet of aer : we say , if in any of these cases it happen , that some small portion of aer be admitted into the cavity of the tube ; we have the evidence of our sense , and the most infallible one too , that the aer so admitted doth not ascend to the top c , but remaine visible in certain small bubbles ( such as usually mount up to the surface of seething water ) immediately upon the superfice of the mercury at the altitude of digits k. as if , indeed , the aer were attracted , and in a manner chained down by the magnetical effluviums of the earth , together with the pendent quicksilver : which having more ansulae or fastnings , whereon the small hooks of the magnetical chains exhaling from the globe of the earth , may be accommodately fixed , is therefore attracted downward more forcibly , and , in that respect , is reputed to have the greater proportion of gravity . again , if upon the inclination of the tube , and the succeeding repletion of the same by the regurgitating mercury , that portion of aer formerly entered be propelled up to the top of the tube , c ; and then the tube again reduced to its perpendicular , so as the quicksilver again deflux to k : in this case the aer doth not remain at c , but sinks down as formerly to k also , and there remains incumbent upon the face of the quicksilver . which descent of the aer cannot be more probably referred to any cause , then the attraction of the magnetick streams of the earth . ( ) having admitted some few bubbles of aer to slide up by the margine of the mercury into the desert space kc ; and then reclined the tube to the altitude of the horizontal line km : you may perceive the delapsed quicksilver not to be repelled up again quite to the top , as before the irreption of aer , but to make a stand when it arrives at the confines of the included aer at op , leaving so much space , as is requisite for the reception of it . nor can it do otherwise , without a penetration of dimensions , by the location of two bodies in one and the same place . ( ) moreover , after the acquiescence of the quicksilver at k , if you stop the inferior extreme d , with your finger , while it remains immersed in the restagnant quicksilver ef , so as to praeclude the irreption of any more aer ; and then invert the tube again : the scene of the desert capacity ck , will be changed to the contrary extreme stopt by your finger , and yet without the least sign of aer pervading the mass of quicksilver in a kind of small stream of bubbles , contrary to what evene's , when aer is admitted into the tube in a small quantity , for in that case , upon the inversion of the tube , you may plainly behold an intersection between the descending quicksilver and the ascending aer , which mounts up through it in a small stream or thread of bubbles . ( ) to those , who conceive that a certain portion of the circumstant aer , being forced by the compression of the restagnant mercury in the vessel , rising higher , upon the deflux of the mercury contained in the tube , doth penetrate the sides of the tube , and so replenish the desert capacity therein : we answer ; that though we deny not but aer may penetrate the pores or incontiguities of glass , since that is demonstrable in weather glasses , and in the experiment of sr. kenelm digby , of making a sensible transudation of mercury mixt with aqua fortis in a bolt-head , through the sides thereof , if gently confricated with a hares-foot on the outside ; yet cannot it be made out , that therefore the desert capacity in the tube is possessed with aer , for two inoppugnable reasons . ( ) because though the tube be made of brass , steel , or any other metal , whose conte●ture is so close , as to exclude the subtlest aer , yet shall the experiment hold the same in all apparences , and particularly in this of the deflux of the quicksilver to the altitude of digits . ( ) because , if the desert cavity were replete with aer ; the incumbent aer could not rush in to the tube , at the eduction of its lower end d , out of the restagnant mercury and water , with such violence ; since no other cause can be assigned for its impetuous rushing into the tube , but the regression of the compressed parts of the ambient aer to their natural laxity , and to the repletion of the violent or forced vacuity . since , if the whole space in the tube were possessed , i. e. if there were as many particles of body , as space therein : doubtless , no part of place could remain for the reception of the irruent aer . secondly , as for that most subtile and generally penetatrive substance , aether , or pure elementary fire which some have imagined universally diffused through the vast body of nature principally for the maintenance of a continuity betwixt the parts thereof ▪ and so the avoidance of any vacuity , though ne're so exile and minute ; we do not find our selves any way obliged to admit , that the desert space in the tube is repleted with the same , untill the propugnators of that opinion shall have abandoned their fallacy , petitio principii , a praecarious assumption of what remains dubious and worthy a serious dispute , viz. that nature d●th irreconcileably abhor all vacuity , per se. for , until they have evinced beyond controversie , that nature doth not endure any emptiness or solution of continuity , quatenus an emptiness , and not meerly ex accidenti , upon some other sinister and remote respect : their position , that she provided that subtile substance , aether , chiefly to prevent any emptiness , is rashly and boldly anticipated , and depends on the favour of credulity for a toleration . nor is it so soon demonstrated , as affirmed , that all vacuity is repugnant to the fundamental constitution of nature . naturam abhorrere vacuum , is indeed , a maxim , and a true one : but not to be understood in any other then a metaphorical sense . for , as every animal , by the instinct of self-conservation , abhors the solution of continuity in his skin , caused by any puncture , wound , or laceration ; though it be no offence to him to have his skin pinkt or perforated all over with insensible pores : so also by the indulgence of a metaphor , may nature be said to abhor any great or sensible vacuity , or solution of continuity , such as is imagined in the desert space of the tube ; though it be familiar , nay useful and grateful to her , to admit those insensible inanities , or minute porosities , which constitute a vacuum disseminatum . we say , by the indulgence of a metaphor ; because we import a kind of sense in nature , analogous to that of animals . and , tollerating this metaphorical speech , that nature hath a kind of sense like that of animals ; yet , if we allow for the vastity of her body can it be conceived no greater trouble or offence to her , to admit such a solution of continuity , or emptiness , as this supposed in the desert space of the tube , then to an animal , to have any one pore in his skin more then ordinarily relaxed and expanded for the transudation of a drop of sweat . this perpended , it can seem no antiaxiomatisme , to affirm , that nature doth not abhor vacuity , per se , but onely ex accidenti : i. e. upon this respect , that in nature is somewhat , for whose sake she doth not , without some reluctany , admit a coacervate or sensible vacuity . now that somewhat existent in nature per se , in relation to which , she seems to oppose and decline any sensible vacuity , can be no other then the fluxility of her atomical particles , especially those of fire , air , and water . and , for ought we poor haggard mortals do , or can , by the light of nature , know to the contrary , all those vast spaces from the margent of the atmosphere , whose altitude exceeds not miles ( according to mersennus and cassendus ) perpendicular , up to the region of the fixed stars ; are not only fluid , but inane ; abating only those points , which are pervaded by the rayes of the sun and other celestial bodies . but , why should we lead the thoughts of our reader up to remote objects , whose sublimity proclaims their incertitude ; when from hence only , that the aer is a fluid substance : it is a manifest , direct and unstrained consequence , that the immediate cause of its avoidance of any sensible or coacervate vacuity , is the confluxibility of its atomical particles ; which being in their natural contexture contiguous in some , though not all points of their superficies , must of necessity press or bear each upon other , and so mutually compel each other , that no one particle can be removed out of its place , but instantly another succeeds and possesses it ; and so there can be no place left empty , as hath been frequently explained by the simile of a heap of sand ? now , if the confluxibility of the insensible particles of the aer , be the immediate and per se cause of its avoidance of any aggregate sensible solution of continuity : we need no farther justification of our position , that nature doth oppose vacuity sensible not per se , but only in order to the affection of confluxibility , i. e. ex accidenti again , should we swallow this praecarious supposition of the aether , with no less pertinacity , then ingenuity asserted by many moderns , but professedly by natalis , in both his treatises ( physica vetus & nova , & plenum experimentis novis confirmatum ) and admit , that nature provided that most tenuious and fluid substance chiefly to praevent vacuity : yet cannot the appetite of our curiosity be satisfied , that the desert space in the tube is replenished with the same , prenetrating through the glass ; untill they have solved that apparence of the violent irruption of the ambient aer into the orifice of the tube , so soon as it is educed out of the subjacent liquors , the quicksilver and water , by the same hypothesis . which whether they have done , so as to demonstrate , that the sole cause of the aers impetuous rushing into the canale of the tube , and prodigiously elevating the ponderous bodies of quicksilver and water residuous therein , is not the reflux of the incumbent aer , by the ascention of the restagnant quicksilver in the vessel , compressed to too deep and diffused a subingression of its insensible particles , to recover its natural laxity , by regaining those spaces , from which it was expelled and secluded ; and to supply the defect of this reason , by substituting some other syntaxical to their hypothesis of the aether , which shall be more verisimilous and plausible : this we ought to refer to the judgment of those , who have attentively and aequitably perused their writings . lastly , as for the third thing supposed to replenish the desert space in the tube , viz. a certain spiritual efflux , or halitus , in this exigent , educed out of the mass of quicksilver , by a secret force of nature , which makes any shift to avoyd that horrid enemy of hers , inanity ; we deny not the possibility of extracting or exhaling a spiritual substance from quicksilver , fine enough to possess such a space , without obnubilating it : but cannot conceive in this case , what should be the efficient of that extraction ; for who can acquiess in that general , a secret force of nature ? ( ) what becomes of that exhalation , when the tube , meerly upon its reclination to the altitude of the horizontal line , k. m. is repossessed with mercury ; for , to admit its reduction to what it was before separation , is to suppose a second secret force in nature syncritical , or conjunctive , antagonist to the former diacritical or separative , which operateth without heat , as the other without cold : and to admit , its expiration through the pores or incontiguities of the glass , is either to suppose the same portion of quicksilver rich enough in spirit to replenish that desert space a thousand times successively , in case the tube be so often elevated and reclined ; for if all the spiritual substance be once exhausted , then must that fox , nature , recur to another expedient , or else tollerate a vacuity coacervate ; or to suppose that the same exhalation doth again return into the glass , by the same slender ways it expired , which is a fancy worthy the smile of heraclitus . ( ) how this halitus , in respect it is praesumed more rare and subtile , then the aer admittible by the orifice of the tube , upon its reseration , can consist without inanity disseminate : which implicateth an universal plenitude . and these are the reasons , which at first inclined our judgement to determine on their part , who opinion the desert space in the tube to be an absolute coacervate vacuity . but , it was not long , before our second and more circumspect cogitations , assisted by time , which insensibly delivered our mind from that pleasant enchantment of novel conceptions , and reduced it to that just temper of indifferency , requisite to sincere discernment and aequitable arbitration ; perpending also the arguments impugning the former perswasion of a coacervate vacuity , and diminishing it down onely to a disseminate one in the desert space of the tube : found them , by incomparable excesses , to preponderate the former , and with many more grains or moments of verisimilty to counterpoyse our judgement to their end of the balance . and the arguments negative , are these . ) manifest it is even to the most critical of our senses , that ligh tpenetrating the sides of the glass tube , doth totally pervade the desert space : therefore it cannot be an absolute sensible vacuum . now , that light is a body , or that the rayes of light are certain ▪ corporeal , though most minute effluviums transmitted from the luminous body , or focus ; is a truth so universally embraced by all knowing men , and upon such apodictical commendations , that here to demonstrate it , would not only be an unseasonable digression , but a criminal parergy . ( ) though the tube might be made of some metal , or other material , whose contexture of atomical particles is so dense and compact , as not to permit the trajection of the beams of light ; and though the experiment would be the same , in all apparences , if made in the dark : yet may the desert space be possessed by the subtle atoms of heat , or cold , proceeding from the ambient aer , and insinuating themselves through the incontiguities of the tube . that the atoms of heat and cold ordinarily transfix glass , is evident from the experience of weather-glasses : in which the cause of the descent of the water included , is the rarefaction of the aer therein by the heat , and the cause of the ascent of the water in cold weather , is the condensation of the same aer by cold ; neither of which were possible , if the subingression of cold and hot atoms through the glass were excluded . and , that the aer incarcerated in a thermometre , or temperamental organ of silver , coper , or brass , is subject to the same mutations of qualities , upon the same vicissitude of causes : hath been so frequently experimented , as to cut off all praetext of diffidence . which is also a sufficient manifest , that the atoms of heat and cold are more exile and penetrative , then those of the common aer of use to animals in respiration : insomuch as they insinuate themselves through such bodies , whose almost continued parts interdict the intrusion of the grosser particles of aer , which cannot permeate through ordinary glass . ( ) because , if you shut your self in a closet , or chamber , that hath but one small window consisting of one entire pane of glass , and that so caemented into lead , as that no chinke is left between ; and whose cranies as well in the door , as elsewhere are all damm'd up : you cannot hear the voice of another person , though speaking very loud and near the glass on the outside , notwithstanding you lay your ear close thereunto . now , since a sound ( at least the vehicle of a sound ) can be nought else , but a subtle portion of the aer modified ; as shall be professedly commonstrated , when time hath brought us so far on our praesent journey , as the proper place for our enquiry into the nature of sounds : and yet this so subtle and fine a portion of the aer cannot penetrate glass of an ordinary thickness : we have the auctority of no weak nor obscure reason , to countenance this our conjecture , that the atoms of cold and heat , are more exile and searching , then the common aer . ( ) if you include small fishes in a large vial of the thinnest glass , filled with river water ; they may live therein for many months , provided the orifice of the glass remain open and free to the aer : but , if you once stop it , so as to exclude the aer , they shall expire in few moments . whence we may conclude , that however fishes seem to have an obscure kind of respiration , such as may be satisfied with that small portion of aer , which is commixt with water : yet is not that thin and subtile aer , supposed to penetrate glass , the same they ( or any other animal ) use in respiration . which had those grand masters of mysterious disquisitions , mersennus and robervallius animadverted ; they might have soon divined , what would be the event of their intended experiment , of including some small animal , as a mouse or grashopper , in a glass of sufficient capacity , and luting on the same on the top of the tube , where the desert space useth to be , in the experiment of mercury , so to try whether the vital organs thereof could keep on their motions in a place devoid of aer : insomuch as that purer substance dimanant from the region of the circumjacent aer , is not corporeal enough to serve the necessity of respiration in any animal , though ne're so minute . the manner of making this experiment , is , by mersennus ( p. . reflect . physicomathemat . ) praescript , thus : porro , operae praetium foret aliquam muscam admodum vegetam & robustam , v. c. crabronem , aut vespam , in tubo includere , priusquam mercurio impleretur , ut post depletionem ad altitudinem digit . proximè , videretur n●m in eo vacuo , aut , si mavis , aethere viveret , ambularet , volaret , & num bombus à volante produceretur . ( ) deducting the possibility of both these , there yet remains a third substance , which may well be conceived to praevent a coacervate vacuity in the forsaken space of the tube : and that 's the magnetical efflux of the earth . for ( ) that the terraqueous globe is one great magnet , from all points of whose superfice are uncessantly deradiated continued threads or beams of subtle insensible aporrhaea's , by the intercession whereof all bodies , whose descent is commonly adscribed to gravity , are attracted towards its centre ; in like manner as there are continually expired from the body of the loadstone invisible chains , by the intercession whereof iron is nimbly allected unto it : is so generally conceded a position among the moderns , and with so solid reasons evicted by gilbert , kircher , cartesius , gassendus and others , who have professedly made disquisitions and discourses on that subject ; that we need not here retard our course , by insisting on the probation thereof . ( ) that , as the magnetical expirations of the loadstone , are so subtle and penetrative , as in an instant to transfix and shoot through the most solid and compact bodies , as marble , iron , &c. without impediment ; as is demonstrable to sense , the interposition of what solid body soever , situate within the orb of energy , in no wise impeding the vertical or polory impregnation of a steel needle by a magnet loricated , or armed : so also the magnetical effluvias of the globe of earth do pervade and pass through the mass of quicksilver contained both in the tube , and the vessel beneath it , and fixing their uncinulae or hamous points , on the ansulae , or fastnings of the quicksilver therein , attract it downward perpendicularly toward the centre : is deduceable from hence , that if any bubbles of aer chance to be admitted into the tube together with the quicksilver , that aer doth not ascend to the top of the tube , but remains incumbent immediately upon the summity of the quicksilver , as being , in respect of its cognation to the earth , attracted and as it were chained down by the magnetical , emanations of the earth transmitted through al interjacent bodies , and hooked upon it . for we shall not incur the attribute of arrogance , if we dare any man to assign the incumbence of the aer upon the mercury , to any more probable cause . it being , therefore most verisimilous , that the earth doth perpetually exhale insensible bodies from all points of its surface , which tending upward in direct lines , penetrate all bodies situate within the region of vapors , or atmosphere without resistence ; and particularly the masses of quicksilver in the tube and subjacent vessel : we can discover no shelf , that can disswade us from casting anchor in this serene haven ; that the magnetical exhalations of the earth , do possess the desert space in the tube , so as to exclude a sensible vacuity . we said , so as to exclude a sensible vacuity , thereby intimating that it is no part of our conception , that either the rayes of light , or the atoms of heat and cold , or the magnetical effluvia●s of the earth , or all combined together , do so enter and possess the desert ●pace , as to cause an absolute plenitude therein . for , doubtless , were all those subtle effluxions coadunated into one dense and solid mass ; it would not arise to a magnitude equal so much as to the th , nay the th part of the capacity abandoned by the delapsed mercury . but fill it to that proportion , as to leave only a vacuity disseminate : such as is introduced into an aeolipile , when by the atoms of fire entered into , and variously discurrent through its concavity , the insensible particles of aer and water therein contained , are reduced to a more lax and open order , and so the inane incontiguities betwixt them ampliated . and this we judge sufficient concerning the solution of the first difficulty . sect . iii. the second capital difficulty . what is the immediate remora , or impediment , whereby the aer , which in respect of the natural confluxibility of its insensible particles , so strongly and expeditely praeventeth any excessive vacuity , in all other cases , is forced to suffer it in this of the experiment ? the solution . insomuch as the fluidity , or confluxibility of the atomical or insensible particles of the aer , is the proxime and sole cause of natures abhorrence of all sensible vacuity ; as hath been proved in the praecedent section : manifest it is , that whosoever will admit a vacuity excessive , or against the rite of nature , must , in order to the introduction or creation thereof , admit also two distinct bodies ; ( ) one , which being moved out of its place , must propel the contiguous aer forward . ( ) another , which interposed , must hinder the parts of the circumstant aer , propulsed by the parts of the aer impelled by the first movent , from obeying the confluxibility of their figure , and succeeding into the place deserted by the body first moved . which is the very scope , that the profound galilaeo proposed to himself , when he invented a wooden cylindre , as an embolus or sucker to be intruded into another concave cylindre of brass , imperviously stopped below ; that by the force of weights appended to the outward extreme , or handle thereof , the sucker might be gradually retracted from the bottom of the concave , and so leave all that space , which it forsaketh , an entire and coacervate vacuum . upon which design torricellius long after meditating , and casting about for other means more conveniently satisfactory to the same intention ; he most happily lighted upon the praesent experiment : wherein the quicksilver became an accommodate substitute to galilaeo's wooden sucker , and the glass tube to the brass concave cylindre . the remaining part of the difficulty , therefore , is only this relative scruple ; how the aer can be propelled by the wooden sucker , downward , or by the restagnant quicksilver in the vessel , upward , when externally there is provided no void space for its reception ▪ for , indeed in the ordinary translation of bodies through the aer , it is no wonder that the adjacent aer is propelled by them ; since they leave as much room behind them , as the aer propelled before them formerly possessed , whereinto it may and doth recur : but in this case of the experiment , the condition is far otherwise , there being , we confess , a place left behind , but such as the aer propelled before cannot retreat into it , in regard of the interposition of another dense solid & impervious body . upon which consideration , we formerly and pertinently reflected when reciting some of those experiments vulgarly objected to a vacuum disseminatum , we insisted particularly upon that of a garden irrigatory : shewing , that the reason of the waters subsistence , or pendency therein , so long as the orifice in the neb remains stopped , is the defect of room for the aer pressed upon by the basis of the water to recur into upon its resignation of place ; because all places being full , there can be none whereinto the inferior aer may recede , until upon deobstruction of the hole above , the circumjacent aer enters into the cavity of the vessel , and resignes to the aer pressed upon below , and so the motion begins and continues by a successive surrender of places . for , though the aer contiguous to the bottom of the irrigatory , be not sufficient to resist the compressure of so great a weight of water , by the single renitency of the confluxibility of its atomical particles ; yet the next contiguous aer , possessing the vicine spaces , and likewise wanting room to recede into , when compelled by the first aer , aggravates the resistence : which becomes so much the greater , by how much the farther the pressure is extended among the parts of the circumjacent aer ; and by so much the farther , is the pressure of the circumjacent aer extended , by how much the greater is the pressure of the next contiguous aer ; and that pressure is proportionate to the degrees of gravity and velocity in the body descendent . which is manifestly the reason , why the water doth not descend through the perforated bottom of the vessel , viz. because the gravity thereof is not sufficient to counterpoyse so diffused , prolix , and continued resistence , as is made and maintained by the confluxibility of the parts of the circumambient aer successively uniting their forces . notwithstanding this seeming plenitude , we may absolve our reason from the intricacy of the scruple , by returning : that , though all places about the tube are filled with aer , yet not without some laxity . so , though there be , indeed , no sensible or coacervate space , wherein there are not some parts of the aer : yet are there many insensible or disseminate spaces , or ●oculaments variously interspersed among the incontiguous ( in all points ) particles of the aer , which are unpossessed by any tenent at all . for the familiarizing of this nicety , let us have recourse once again to our so frequently mentioned example of a heap of corne. when we have poured corne into a bushel up to the brim thereof ; the capacity seems wholly possessed by the graines of corne , nor is there therein any space , which sensibly contains not some graines : yet if we shake the bushel , or depress the corne , the graines sink down in a closer posture , and leave a sensible space in the upper part of the bushel , capable of a considerable access or addition . the reason is , that the grains , at their first infusion , in respect of the ineptitude of their figures for mutual contact , in all points of their super●icies , intercept many empty spaces betwixt them ; which dispersed minute inane spaces are reduced to one great and coacervate or sensible space , in the superior part of the continent , when , by the succussion of the vessel , the grains are disposed into a closer posture , i. e. are more accommodated for mutual contingency in their ends and sides . thus also may aer be so compressed , as the granules , or insensible particles of it , being reduced to a more close or dense order , by the s●bingression of some particles of the aer nearest to the body compressing , into the incontiguities of the next neighbouring aer ; may possess much less of space , then before compression ; and consequently surrender to the body propelling or compressing , leaving behind a certain space absolutely devoid of aer , at least , such as doth appear to contain no aer . but this difficulty , hydra-like , sends out two new heads in the room of one cut off . for , curiosity may justly thus expostul●te . ( ) have you not formerly affirmed , that no body can be moved , but it must compel the aer forward , to suffer a certain subingression of its insensible particles into the pores , or loculaments of the next contiguous aer , such as is requisite to the leaving of a space behind it for the admission of the body moved ? and , if so ; how comes it , that when most bodies are moved through the aer , with so much facility , and therefore cause the parts thereof before them to intrude themselves into the incontiguities of the next vicine aer , with a force so small , as that it is altogether insensible : yet in this case of the experiment , is required so great a force to effect the subingression and mutual coaptation of the parts of the aer ? the cause seems to be this . in all common motions of bodies through the liberal aer , there is left a space behind , into which the parts of the aer may instantly circulate , and deliver themselves from compression ; and so there is a subingression and coaptation of only a few parts necessary , and consequently the motion is tolerated without any sensible resistence : but in this case of the experiment , in regard there is no place left behind by the propellent , into which the compressed parts of the aer may be effused ; necessary it is that the parts of aer immediately contiguous to the body propellent , in their retrocession and subingression compress the parts of the next contiguous aer ; which though they make some resistence ( proportionate to their measure of confluxibility ) do yet yeild , retrocede , and intrude themselves into the incontiguities of the next contiguous aer ; and those making also some resistence , likewise yeild , retrocede , and insinuate themselves into the loculaments of the next , which acts the like part upon the next , and so successively . so that a greater force then ordinary is required to subdue this gradually multiplied resistence successively made and maintained by the many circumfused parts of the aer ; and to effect , that the retrocession , subingression and coaptation of the parts of the aer be propagated farther and farther , untill convenient room be made , for the reception of the body propellent . ( ) whence do you derive this resistence of the aer ? from its gravity . for , the aer of its own nature is heavy , and can be said to be light only comparatively , or as it is less ponderous then water and earth : nor can there be given any more creditable reason of the aers tendency upward here below near the convexity of the earth , then this ; that being in some degree ponderous in all its particles , they descend downwards from the upper region of the atmosphere , and in their descent bear upon and mutually compel each other , untill they touch upon the surface of the earth , and are by reason of the solidity and hardness thereof repercussed or rebounded up again to some distance : so that the motion of the aer upwards near the face of the earth , is properly resilition , and no natural , but a violent one . now , insomuch as the aer seems to be no other , but a common miscelany of minute bodies , exhaled from earth and water and other concretious sublunary , and proportionately to their crassitude or exility , emergent to a greater or less altitude : it can be no illegal process for us to infer , that all parts thereof are naturally endowed with more or less gravity proportionate to their particular bulk ; whether that gravity be understood to be ( as common physiology will have it ) a quality congenial and inhaerent , or ( as verisimility ) their conformity to the magnetick attraction of the earth . and , insomuch as this gravity is the cause of the mutual depression among the particles of aer in their tendency from the upper region of the atmosphere down to the surface of the earth : we may well conceive , that the depression of the inferior parts of the aer by the superior incumbent upon them , is the origine immediate from whence that reluctancy or resistence , observed in the experiment , upon the induction of a praeternatural inanity between the parts thereof . but a farther prosecution and illustration of this particular , depends on the solution of the next problem . sect . iv. the third capital difficulty . what is the cause of the quicksilvers not descending below that determinate altitude , or standard of digits ? solution . the resistence of the parts of the aer , which endures no compression , or subingress of its insensible particles , beyond that certain proportion , or determinate rate . to profound this mystery of nature to the bottom , we are to request our reader to endure the short recognition of some passages in our praecedent discourses . ( ) that upon the ordinary translation of bodies through the aer , the resistence of its insensible parts is so small , as not to be discoverable by the sense ; because the subingression of its contiguous parts into the loculaments of the next vicine aer , is only perexile , or superficial : and that we may safely imagine this superficial subingression not to be extended beyond the thickness of a single hair ; nay , in some cases , perhaps , not to the hundreth part thereof . so stupendiously subtle are the fingers of nature in many of her operations . but , that the resistence observed in the present experiment , for the enforcing of a praeternatural vacuum , is therefore deprehensible by the sense , because in respect of a defect of place behind the body propellent , into which the parts of the aer compelled forward may circulate , the subingression must be more profound ; and so the resistence being propagated farther and farther by degrees , must grow multiplied , and consequently sensible . ( ) that the force of the body propellent is greater , then the force of the next contiguous aer protruding the next , and the force of the third protruded wave of the aer ( for a kind of undulation may be ascribed to aer ) greater on the fourth , then that of the fourth upon the fifth , and so progressionally to the extrem of its diffusion or extension : so that the force becomes so much the weaker and more oppugnable , by how much the farther it is extended ; and dwindles or languishes by degrees into a total cessation . ( ) that , as upon the succussion , or shock of a bushel apparently full of corn , is left a certain sensible space above , unpossessed by any part or grain thereof ; which coacervate empty space responds in proportion to those many disseminate vacuola , or loculaments intercepted among the incontingent sides of the grains , before their reduction to a more close order by the succussion of the bushel : so likewise , upon the impulse of the aer by a convenient body , is left behind a sensible space absolutely empty , as to any part of aer ; which coacervate empty space must respond in proportion to those many disseminate spaces intercepted among the incontiguous parts , or granules of the aer , before their reduction to a more close order , or mutual subingression and coaptation of sides and points , by the body compressing . these notions recogitated , our speculations may progress with more advantage to explore the proxime and proper cause of the mercuries constant subsistence at the altitude of digits , in the tube perpendicularly erected . for , upon the credit of their importance , we may justly assume ; that upon the compression of the circumambient aer by a small quantity of quicksilver ( suppose only of two or three inches ) impendent in the concave of the tube , can be caused , indeed , some small subingression of the particles thereof ; but such , as is only superficial and insensible : in respect the weight of so small a proportion of quicksilver is not of force sufficient to propel the parts of the aer to so great a crassitude that the space detracted from the aggregate of disseminate vacuities should amount to that largness , as to become visible above the quicksilver in the tube ; since the quantity of the quicksilver being supposed little , the force of reluctancy , or resistence in the parts of the aer , arising from their inhaerent fluidity , must be greater then the force of compression arising from gravity ; and therefore there succeeds no sensible deflux of the quicksilver . but , being that a greater and greater mass of quicksilver may be successively infused into the tube , and so the compressive force of its gravity be respectively augmented ; and thereupon the aer become less and less able successively to make resistence : 't is difficult not to observe , that the proportion of compression from gravity in the quicksilver , may be so equalized to the resistence from gravity in the aer , as that both may remain in statu quo , without any sensible yeilding on either side . hence comes it , that at the aequipondium of these two antagonists , the space in the tube detracted from the aggregate of minute inanities disseminate in the aer , is so small as not to be commensurated by sense : and at the cessation of the aequilibrium , or succeding superiority of the encreased weight of the quicksilver , the parts of the aer being compelled thereby to a farther retrocession and subingression ; the space detracted from the aggregate of disseminate vacuities in the aer , becomes larger , and consequently sensible , above the quicksilver in the upper region of the tube . this may be most adaequately illustrated , by the simile of a strong man , standing on a plane pedestal , in a very high wind . for , as he by a small afflation or gust of wind , is in some degree urged or prest upon , though not so much as to cause him to give back ; because the force of his resistence is yet superior to that of the wind assaulting and impelling him ; nor , when the force of the wind grows upon him even to an aequilibrium , is he driven from his station , because his resistence is yet equal to the impulse of the wind ; but when the force of the wind advances to that height , as to transcend the aequilibrium , then must the man be compelled above the rate of his resistence , and so be abduced from the place of his station : so likewise , while there is only a small quantity of quicksilver contained in the tube , though , by the intervention or mediation of the quicksilver restagnant in the subjacent vessel , it press upon the parts of the incumbent aer , in some degree ; yet is not the aer thereby urged so , as to be compelled to retrocede , and permit the restagnant quicksilver to ascend higher in the vessel ; and therefore the quicksilver impendent in the tube cannot descend , because the restagnant wants room to ascend . but , when the quantity , and so the gravity of the quicksilver contained in the tube is so augmented , as to exceed the resistence of the aer ; then is the aer compelled or driven back , by the restagnant quicksilver rising upwards , to a sensible subingression of its atomical particles , and the quicksilver in the tube instantly defluxeth into the place resigned by the restagnant , until it arriveth at that point of altitude , or standard , where the resistence of the aer becomes again equal to the force compressing it , and there subsisteth , after various reciprocations up and down in the tube . now concerning the remaining , and , indeed , the most knotty part of the difficulty , viz. why the aequilibrium of these two opposite forces , is constant to the certain praecise altitude of digits ? of this admirable magnale no other cause seems worthily assignable , but this ; that such is the nature of aer , in respect both of the atomical particles of which it is composed , and of the disseminate vacuities variously interspersed among them , as that it doth resist compression at such a determinate rate , or definite proportion , as exactly responds to the altitude of digits . should it be demanded of us , why he , who stands on a plane , doth resist the impulse of a mighty wind to such a determinate rate or height , but not farther : we conceive our answer would be satisfactory to the ingenious , if we returned only , that such is the exact proportion of his strength , resulting from the individual temperament of his body . we are men , i. e. moles ; whose weak and narrow opticks are accommodated only to the inspection of the exterior and low parts of nature , not perspicacious enough to penetrate and transfix her interior and abstruse excellencies : nor can we speculate her glorious beauties in the direct and incident line of essences and formal causes , but in the refracted and reflected one of effects ; nor that , without so much of obscurity , as leaves a manifest incertitude in our apprehensions , and restrains our ambition of intimate and apodictical science , to the humble and darksome region of mere superficial conjecture . such being the condition of our imperfect intellectuals ; when we cannot explore the profound recesses , and call forth the formal proprieties of some natures , but find our disquisitive faculties terminated in the some apparences , or effects of them : it can be no derogation to the dignity of humanity , for us to rest contented , nay thankful to the bounty of our creator , that we are able to erect verisimilous conjectures concerning their causation , and to establish such rational apprehensions or notions thereupon , as may , without any incongruity , be laudably accommodated to the probable solution of other consimilar effects , when we are required to yeild an account of the manner of their arise from their proper originals . thus , from our observation of other things of the like condition , having extracted a rational conjecture , that this so great gravity of the quicksilver doth depend upon the very contexture of its insensible particles , or minute bodies , whereof it doth consist , by which they are so closely and contiguously accommodated each to other in the superficies of their points and sides , as no body whatever ( gold only excepted ) doth contain more parts in so small a bulk , nor consequently more ansulae , or fastnings , whereon the magnetique hooks of the earth are fixable , in order to its attraction downward : and on the contrary , that the so little gravity of the aer , depends on a quite dissimilar contexture of its insensible particles , of which it is composed , by which they are far less closely and contiguously adapted each to other , and so incomparably fewer of them are contained in the like space , and consequently have incomparably fewer ansulae or fastnings , whereon the hooks of the magnetick chains of the earth may be fixed : having , we said , made this probable conjecture , what can be required more at our hands , then to arrest curiosity with this solution ; that the aer is of such a nature , i. e. consisteth of such insensible particles , and such inane spaces interspersed among them , as that it is an essential propriety of it , to resist compression , to such a determinate rate , and not beyond ? had we bin born such lyncei , as to have had a clear and perspect knowledge of the atoms of aer , of their figure , magnitude , the dimensions of the inane spaces intercepted among them , of the facility or difficulty of their reciprocal adaptation , of the measure of their attraction , the manner and velocity of their tendency , &c. then , indeed , might we , without any complex circumambage of discourse , have rendered the express and proper reason , why the aer doth yeild praecisely so much , and no more to the gravity of the quicksilver compressing it . since we were not , it may be reputed both honour and satisfaction , to say ; that it is essential to the natures of mercury and aer , thus and thus opposed , to produce such and only such an effect . however , that we may not dismiss our reader absolutely jejune , who came hither with so great an appetite ; we observe to him , that the constant subsistence of the mercury at the altitude of digits , doth seem rather to proceed from the manifest resistence of the aer , then from any secret quality in the mercury , unless its proportion of gravity be so conceived . this may be collected from hence ; that water infused into the tube doth also descend to the point of aequipondium , and stops at the altitude of feet , nor more , nor less ; and in that altitude becomes aequiponderant to the mercury of digits . so that it is manifest , that with what liquor soever the tube be filled , still will the aer resist its deflux at a certain measure : provided only , that the tube be long enough to receive so much of it , as the weight thereof may equal that of the mercury at digits , or the water at feet . here we meet an opportunity also of observing to him , by how admirable an analogy this respective aequality of the weights of quicksilver and water , in these so different altitudes , doth consent with the absolute weight of each . when , as the weight of quicksilver carries the same proportion to the weight of water , of the same measure or quantity , as to : so reciprocally doth the altitude of feet , carry the same proportion to digits , as to . and hence comes it , that , if water be s●peraffused upon the restagnant quicksilver in the vessel under the tube ; the quicksilver doth instantly ascend above the standard of digits , higher by a ●● . part of the water superaffused . which truly , is no immanifest argument , that the aer , according to the measure of its weight , or the praecise rate of its resistence , becomes aequilibrated to the mercury at the altitude of dig . since the superaffused water doth no more then advance the aequilibrium according to the rate of its weight , or proportion of resistence . besides , it is farther observable , that because the tube is replenished by a th part in dig . of the altitude , above the first aequilibrium ( a proportionate access to the mercury in the tube , being made by a like part of that in the subject vessel , impelled into it ) therefore is the vacuum above the mercury in the tube , diminished also by one th . part ; and the compression of the aer , impendent on the surface of the restagnant mercury , relaxed and diminished also by a th part . so that if the vessel underneath the tube be large enough to admit an addition of water successively affused , until so much of the restagnant mercury , as formerly descended , shall be again propelled up into the tube : then must the whole tube be replenished , and so the whole vacuity disappear , for then all compression of the incumbent aer ceaseth , and so much space as was possessed before the experiment , both without and within the tube , by the mercury , water , aer , is again repleted . if you shall still insist , and urge us to a praecise and definite account of the weight of the quicksilver contained in the tube to the altitude of digits , and of the water of feet ; which makes the aequilibrium with the opposite weight of the circumstant aer : our answer is , that the exact weight of neither can be determined , unless the just diameter or amplitude of the tube be first agreed upon . for albeit neither the longitude nor the amplitude of the tube makes any sensible difference in this phaenomenon of the experiment , the aequilibrium being still constant to the same altitude of digits , for the mercury , and feet for water : yet , according as the cavity of the tube is either smaller , or greater , must the weight of the liquors contained therein be either less , or more . since therefore , we are to explore the definite weight of the liquor contained , by the determinate amplitude of the tube containing ; suppose we the diametre of the cavity of the tube to be one third part of a * digit , and we shall find the weight of the quicksilver , from the base to the altitude of digits , to be near upon two pound , paris weight : and upon consequence the weight of water in the same tube , of feet in altitude , to be the same ; and the weight of the cylindre of aer , from its base incumbent on the surface of the restagnant quicksilver , up to its top at the summity of the atmosphere , to be also the same ; otherwise there could be no aequilibrium . here , as a corollary , we may add , that insomuch as the force of a body attrahent may be aequiparated to the weight of another body spontaneously descending or attracted magnetically by the earth : thereupon we may conclude , that the like proportion of weight appended to the handle of the wooden sucker , may suffice to the introduction of an equal vacuum , in galilaeo's brass cylindre . but , perhaps , you 'l object ; that this seems rather to entangle then dissolve the riddle . since by how much the larger the cavity of the tube , by so much the greater the quantity , and so the weight of the quicksilver contained : and by how much the greater the weight , or force of the depriment , by so much the more must the depressed yeild , and consequently , so much the lower must the aequilibrium be stated . to extricate you from this labyrinth , we retort ; that the cause of the aequilibriums constancy to the point of digits , whatever be the quantity of the mercury contained in the tube , is the same with that , which makes the descent of two bodies of the same matter , but different weights , to be aequally swift : for a bullet of lead of an ounce , falls down as swiftly as one of pound . for , in respect , that a cylindre of quicksilver contained in a tube of a large diametre , doth not descend more swiftly , then a cylindre of quicksilver contained in a tube of a narrow diametre : therefore is it , that the one doth not press the bottom , upon which as its base , it doth impend , more violently then the other doth press upon its base ; and consequently , the restagnant quicksilver about the larger cylindre doth not , in its elevation or rising upward , more compress the basis of the impendent cylindre of aer , then what is restagnant about the lesser cylindre . whereupon we may conclude , that a great cylindre of aer resisting a great cylindre of quicksilver , no less then a small doth resist a small : therefore ought the aequilibrium betwixt the depressure of the quicksilver , and the resistence of the circumstant aer , to be constant to the altitude of digits , aswell in a large , as a narrow tube . which reason may also be accommodated to water and all other liquors . sect . v. the fourth capital difficulty . why is the deflux of the quicksilver alwayes stinted at the altitude of digits , though in tubes of different longitudes ? when it seems more reasonable , that according to the encrease or enlargement of the inanity in the upper part of the tube , which holds proportion to the longitude thereof ; the compression , and so the resistence of the aer circumpendent , ought also to be encreased proportionately : and consequently , that the aequilibrium ought to be so much the higher in the tube , by how much the greater resistence the aer makes without ; because , by how much a larger space is detracted from the aer , by so much more diffused and profound must the subingression of its atomical particles be , and so the greater its resistence . solution . certain it is , aswel upon the evidence of sense , as the conviction of several demonstrations excogitated chiefly by mersennus ( in phaenom ▪ hydraulic . ) that a cylindre of any liquor doth with so much the more force or gravity impend upon its base , or bottom , by how much the higher its perpendicular reacheth , or , by how much the longer it is : and consequently , having obtained a vent , or liberty of exsilition below at its base , issues forth with so much the more rapidity of motion . and this secret reveals what we explore . for , according to the same scale of proportions , we may warrantably conceive ; that , by how much the higher the cylindre of quicksilver is in the tube , by so much the more forcibly it impendeth upon its base , in the restagnant quicksilver ; and so having obtained a vent below , falleth with so much the more rapidity of motion or exsilition thereupon : and upon consequence , by so much the more violently is the incumbent aer compressed by the restagnant quicksilver ascending , its resistence overcome , and the subingression of its insensible particles into the inane loculaments of the vicine aer , propagated or extended the farther ; and the space detracted from the aggregate of disseminate inanities , so much the larger , and consequently the coacervate vacuum apparent in the superior region of the tube , becomes so much the greater . and , because the resistence made against the subingression , dilating or distending it self , is in the instant overcome , by reason of a greater impulse caused by the cylindre of mercury descending from a greater altitude ; and that resistence remains , which could not be overcome , by the remnant of the mercury in the tube , at the height of digits : therefore , is this remaining degree of resistence , the manifest cause , why the mercury is aequilibrated here at the point of digits , aswell when it falls from a high as a low perpendicular . this may receive a degree of perspicuity more , from the transitory observation of those frequent reciprocations of the quicksilver , at the first deflux of it into the restagnant , before it acquiesce and fix at the point of aequiponderancy : no otherwise then a ball bounds and rebounds many times upon a pavement , and is by successive subsultations uncessantly agitated up and down , untill they gradually diminish and determine in a cessation or quiet . the cause of which can be no other then this ; that the extreme or remotest subingression of the insensible particles of the aer , is ( we confess ) propagated somewhat farther , then the necessity of the aequipondi●m requireth , by reason of a new access of gravity in the quicksilver ; but , instantly the insensible particles of the aer , being so violently and beyond the rate of subingressibility prest upon , and made as it were more powerful by their necessary reflexion , then the re●idue of quicksilver remaining in the tube ; result back to their former station of liberty , with that vehemency , as they not only praevent any further subingression , and reduce the even-now-superior and conquering force of the quicksilver to an equality ; but also repell the quicksilver delapsed up again into the tube above the point of the aequipondium : and again , when the quicksilver defluxeth , but not from so great an altitude , as at first ; then is the aer again compelled to double her files in a countermarch , and recede from the restagnant quicksilver , though not so far , as at first charge . and thus the force of each being by reciprocal conquests gradually decreased , they come to that equality , as that the quicksilver subsists in that point of altitude , wherein the a●quilibrium is . sect . vi. the fifth capital difficulty . what force that is , whereby the aer , admitted into the lower orifice of the tube , at the total eduction thereof out of the restagnant quicksilver and water ; is impelled so violently , as sufficeth not only to the elevation of the remaining liquors in the tube , but even to the discharge of them through the sealed extreme , to a considerable height in the aer ? solution . the immediate cause of this impetuous motion , appears to be only the reflux , or resilition of the so much compressed basis of the cylindre of aer , impendent on the surface of the restagnant liquors , quicksilver and water , to the natural laxity of its insensible particles upon the cessation of the force compressive : the principle , and manner of which restorative or re●lexive motion , may be perspicuously deprehended , upon a serious recognition of the contents of the last article in the praecedent chapter of a disseminate vacuum ; and most accommodately exemplified in the discharge or explosion of a bullet from a wind-gun . for , as the insensible particles of the aer included in the tube of a wind-gun , being , by the embolus or rammer , from a more lax and rare contexture , or order , reduced to a more dense and close ( which is effected , when they are made more contiguous in the points of their superfice , and so compelled to diminish the inane spaces interjacent betwixt them , by subingression ) are , in a manner so many springs or elaters , each whereof , so soon as the external force , that compressed them , ceaseth ( which is at the remove of the diaphragme or partition plate in the chamber of the tube ) reflecteth , or is at least reflected by the impulse of another contiguous particle : therefore is it , that while they are all at one and the same instant executing that restorative motion , they impel the bullet , gaged in the canale of the tube , before them with so much violence , as enables it to transfix a plank of two or three digits thickness . so also do the insensible particles of the base of the cylindre of aer incumbent on the surface of the restagnant liquors , remain exceedingly compressed by them , as so many springs bent by external force : and so soon as that force ceaseth ( the quicksilver in the tube , after its eduction , no longer pressing the restagnant mass of quicksilver underneath , and so that by his tumefaction no longer pressing the impendent aer ) they with united forces reflect themselves into their natural rare and liberal contexture , and in that restorative motion drive up the remainder of quicksilver in the canale of the tube to the upper extreme thereof with such violence , as sufficeth to explode all impediments , and shiver the glass . for , in this case , we are to conceive the aer to be aequally distressed betwixt two opposite forces ; on one side by the gravity of the long cylindre of aer from the summity of the atmosphere down to the base impendent on the superfice of the restagnant liquors ; on the other , by the ascendent liquors in the subjacent vessel , which are impelled by the cylindre of quicksilver in the tube , descending by reason of its gravity : and consequently , that so soon as the obex , barricade , or impediment of the restagnant quicksilver , is removed , the distressed aer instantly converteth that resistent force , which is inferior to the gravity of the incumbent aereal cylindre , upon the remainder of the quicksilver in the tube , as the now more superable opponent of the two ; and so countervailing its gravity by the motion of reflexion or restoration , hoyseth it up with so rapid a violence , as the easily frangible body of the glass cannot sustain . which reason doth also satisfie another collateral scruple , viz. why water , superaffused upon the restagnant quicksilver , doth intrude it self as it were creeping up the side of the tube , and replenish the desert space therein ; so soon as the inferior orifice of the tube is educed out of the restagnant quicksilver , into the region of water . for , it is impelled by the base of the aereal cylindre exceedingly compressed , and relaxing it self : the resistence of it , which was not potent enough to praevail upon the greater gravity of the quicksilver in the tube , so as to impel it above the point of aequiponderancy ; being yet potent enough to elevate the water , as that whose gravity is by parts of less then that of the quicksilver . here the inquisitive may bid us stand , and observe a second subordinate doubt , so considerable , as the omission of it together with a rational solution , must have rendred this whole discourse not only imperfect , but a more absolute vacuum , i. e. containing less of matter , then the desert space in the tube ; and that is : how it comes , that during the aequilibrium betwixt the ●eight of the quicksilver in the tube on the one hand , and the long cy●lindre of aer on the other , even then when the base of the cylindre of aer is compressed to the term of subingression ; we find the aer as fluxile , soft , and yeilding , ( for , if you move your hand transversly over the restagnant quicksilver , you can deprehend none the least tensity , rigidity , or urgency thereabout ) as any other part of the region of aer not altered from the laxity of its natural contexture ? we reply , that though nothing occurr in the whole experiment more worthy our absolution ; yet nothing occurrs less worthy our admiration then this . for , if my hand , when moved toward the region of the compressed aer , did leave the space , which it possessed before motion , absolutely empty , so as the aer impelled and dislodged by it could not circulate into the same ; in that case , indeed , might i perceive , by a resistence obvening a manifest tensity or rigidity in the compressed aer : but , insomuch as when my hand leaves the region of the lax aer , and enters that of the compressed , there is as much of space lest in the lax aer for the compressed to recurr into , as that which my hand possesseth in the region of the compressed ; and when it hath passed through the region of the compress'd , and again enters the confines of the lax , there is just so much of the lax aer propelled into the space left in the compressed , as responds in proportion to the space possessed by it in the lax : therefore doth my hand deprehend no sensible difference of fluxility in either , and yet is the urgency or contention of the base of the cylindre of aer impendent upon the restagnant quicksilver , constantly equal , though it may be conceived to suffer an undulation or wavering motion by the traversing of my hand to and again , by reason of the propulse and repulse . this may be enforced by the example of the flame of a candle ; which though ascending constantly with extreme pernicity , or rapidity of motion , and made more crass and tense by the admixture of its own ●uliginous exhalations : doth yet admit the traversing of your finger to and fro through it so easily , as you can deprehend no difference of fluxility between the parts of the flame and those of the circumvironing aer ; the cause whereof must be identical with the former . secondly , by the experience of urinators or divers ; who find the extension and contraction of their arms and legs as free and easie at the depth of fathoms ▪ as within a foot of the surface of the water ; notwithstanding that water comes many degrees short of aer , in the point of * fluidity . thirdly , by the beams of the sun ; for , when these insinuate themselves through some slender hole or crany into a chamber , their stream or thread of solary atoms appears like a white shining wand ( by reason of those small dusty bodies , whose many faces , or superficies making innumerable refractions and reflections of the rayes of light towards the eye ) and constantly maintains that figure , though the wind blow strongly transverse , and carry off those small dusty bodies , or though with a fan you totally dispel them : why ? because fresh particles of dust succeeding into the rooms of those dispelled , and aequally refracting and reflecting the incident radii of light toward the eye , conserve the apparence still the same . so though the wind blow off the first cylindre of comprest aer , yet doth a second , a third , &c. instantly succeed into the same space , so as that region , wherein the base thereof is situated , doth constantly remain comprest : because the compression of the insensible particles of the aer and wind , during their continuation in that region , continues as great as was that of the particles formerly propulsed and abduced . and fourthly , by the rainbow ; which persisteth the same both in the extent of its arch , and the orderly-confused variety of colours : though the sun , rapt on in his diurnal tract , shifts the angle of incidence from one part of the confronting cloud to another , every moment ; and the wind change the scene of the aer , and adduce consimilar small bodies , whose various superficies making the like manifold refractions and reflexions of the incident lines of light , dispose them into the same colours , and praesent the eye with the same delightful apparition . which had the hairbrain'd and contentious helmont in the least measure understood ; he must have blush't at his own most ridiculous whimsy , that the rainbow , is a supernatural meteor , or ens extempore created by divinity , as a sensible symbol of his promise no more to destroy the inhabitants of the earth by water , having no dependence at all on natural causes : especially when the strongest argument he could excogitate , whereby to impugn the common theory of the schools , concerning the production thereof , by the refraction and reflection of the rayes of the sun incident upon the variously figured parts of a thin and rorid cloud in opposition diametrical ; was only this . oculis , manibus , & pedidus cognovi istius figmenti falsitatem . cùm ne quidem simplex nubes esset in loco iridis . neque enim , etsi manu iridem finderem , eamque per colores iridis ducerem , sensi quidpiam , quod non ubique circumquaque in aere vicino : imo non proin colores ●ridis turbabantur , aut confufionem tollerabant . ( in meteor on anomalon . ) sect . vii . the sixth and last capital difficulty . upon the eduction of the lower extreme of the tube out of the region of the restagnant quicksilver , into that of water superaffused ; wherefore doth the water instantly intrude into the tube , and the quicksilver residuous therein by sensible degrees deflux , until it hath totally surrendred unto it ? solution . this phaenomenon can have for its cause no other but the great disparity of weight betwixt those two liquors . for , insomuch as the subsistence of the quicksilver in the erected tube , at the altitude of digits , justly belongs to the aequipondium betwixt it and the circumpendent cylindre of aer ; and the proportion of weight which quicksilver holds to water , is the same that holds to : it must as manifestly , as inevitably follow , that the water , being by so much less able , in regard of its so much minority of weight , to sustain the impulse of the aer uncessantly contending to deliver it self from that immoderate compression , must yeild to the descending base of the aereal cylindre , and so ascend by degrees , and possess the whole space ; every part of quicksilver that delapseth , admitting parts of water into the tube . here occurrs to us a fair opportunity of erecting , upon the praemised foundation , a rational conjecture concerning the perpendicular extent of the region of aer from the face of the terraqueous globe . for , if aer be ● times ( according to the compute of the great mersennus ( reflect . physicomath . pag. ) who exceedingly differs from the opinion of galilaeo ( dialog . al. moviment . pag. . ) and marinus ghetaldus ( in archimed . promot . ) both which demonstrate aer to be only times ) lighter then water , and water times lighter then quicksilver : hence we may conclude ( ) that aer is times lighter then quicksilver ; ( ) that the cylindre of aer aequiponderant to the cylindre of quicksilver of the altitude of digits , is times higher ; and ( ) that the altitude of the cylindre of aer amounts to leucae , or leagues . since times digits ( i. e. digits ) divided by digits ( so many amounting to a french league , that consisteth of feet ) the quotient will be . from the so much discrepant opinions of these so excellent mathematitians , and most strict votaries of truth , galilaeo and mersennus ; each of which conceived his way for the exploration of the exact proportions of gravity betwixt aer and water , absolutely apodictical : we cannot omit the opportunity of observing ; how insuperable a difficulty it is , to conciliate aristotle to euclid , to accommodate those axioms , which concern quantity abstract from matter , to matter united in one notion to quantity , to erect a solid fabrick of physiology on foundations mathematical . which difficulty the ingenious magnenus well resenting , made this a chief praeparatory axiom to his second disputation concerning the verisimility of democritus hypothesis of atoms : non sunt expendendae actiones physicae regulis geometricis ; subnecting this ponderous reason , cum demonstrationes geometricae procedant ab hypothesi , quam probare non est mathematici , sed alterius facultatis , quae eam refellit ; id eo lineis mathematicis , regulisque strictè geometricis , actiones physicae non sunt expendendae . ( democrit . reviviscent . p. . ) and now at length having run over these six stages , in as direct a course , and with as much celerity , as the intricacy and roughness of the way would tolerate ; hath our pen attained to the end of our digression : wherein , whether we have gratified our reader with so much either of satisfaction , or delight , as may compensate his time and patience ; we may not praesume to determine . however , this praesumption we dare be guilty of , and own ; that no hypothesis hitherto communicated , can be a better clue to extricate our reason from the mysterious labyrinth of this experiment , by solving all its stupendious apparences , with more verisimility , then this of a disseminate vacuity , to which we have adhaered . but , before we revert into the straight tract of our physiological journey , the praecaution of a small scruple deduceable from that we have consigned a cylindrical figure to the portion of aer impendent on the surface of the restagnant liquors ; adviseth us to make a short stand , while we advertise ; that though we confess the diametre of the sphere of aer to be very much larger then that of the terraqueous globe , and so , that the aer , from the convex to the concave thereof incumbent on the surface of the restagnant liquors in the vessel placed on the convex of the earth , doth make out the section or frustum of a cone , whose basis is in the summity of the atmosphere ; and point at the centre of the earth ( as this diagram exhibiteth . ) note that neither earth , aer , vessel , nor tube , are delineated according to their due proportions : since so , the earth would have appeared too great , and the rest too small , for requisite inspection . yet , insomuch as the aer is aequiponderant to the cylindre of quicksilver contained in the tube ( the only requisite to our praesent purpose ) no less in the figure of a cone , then in that of a cylindre ; and since both mersennus and gassendus ( to either of which we are not worthy to have been a meer amanuensis ) have waved that nicety , and declared themselves our praecedents , in this particular : we have thought our selves excusable for being constant to the most usual apprehension , when the main interest of truth was therein unconcerned . chap. vi. of place . sect . i. that inanity and locality bear one and the same notion , essentially , and cannot be rightly apprehended under different conceptions , but respectively ; or , more expresly , that the same space , when possessed by a body , is a place , but when left destitute of any corporeal tenent whatever , then it is a vacuum : we have formerly insinuated , in the third article , sect. . of our chap. concerning a vacuum in nature . which essential identy , or only relative alterity of a vacuum and place , is manifestly the reason , why we thus subnect our praesent enquiry into the nature or formality of place , immediately to our praecedent discourse of a vacuum : we conceiving it the duty of a physiologist , to derive his method from nature , and not to separate those things in his speculation , which she hath constituted of so near affinity in essence . among those numerous and importune altercations , concerning the quiddity or formal reason of place , in which the too contentious schools usually lose their time , their breath , their wits , and their auditors attention ; we shall select only one quaestion , of so much , and so general importance , that , if rightly stated , calmly and aequitably debated , and judiciously determined , it must singly suffice to imbue the mind of any the most curious explorator , with the perspicuous and adaequate notion thereof . epicurus ( in epist. ad herodot● ) understands place to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , intervallum illud , quod privatum corpore , dicitur inane , & oppletum corpore , locus : that interval , or space , which being destitute of any body , is called , a vacuum , and possessed by a body , is called place . and aristotle ( in . auscult . natur. cap. . ) thinks he hath hit the white , when he defines place to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , circumdantis corporis extremum immobile primum ; concava nempe , seu proxima immediataque , & ipsum locatum contingens corporis ambientis superficies : the concave , proxime , immediate superfice of the body circumambient , touching the locatum . now the difficulty in quaestion , is only this : whether this definition of aristotle , or that modest description of epicurus , doth with the greater measure of verisimility and perspicuity respond to the nature of what we ought to understand , in propriety of conception , signified by the word , place . in order to our impartial perpension of the moments of reason on each side , requisite it is , that we first strictly ponder the hypothesis , or ground , on which aristotle erected his assertion , which is this ; praeter dimensiones corporis locati , & ipsam ambientis superficiem , nullas alias dari ( in . physic . . ) that in nature are none but corporeal dimensions : for , if we can discover any other dimensions , abstruct from corporiety , such wherein the formal reason of space may best and most intelligibly be radicated ; it can no longer remain in the suspence of controversie , how unsafe it is for the schools to recurr to that superstructure , as a sanctuary impraegnable , whose foundation is only sand , and depends for support upon no other but a praecarious supposition . imagine we , therefore , that god should please to adnihilate the whole stock or mass of elements , and all concretions resulting there-from , i. e. all corporeal substances now contained within the ambite , or concave of the lowest heaven , or lunar sphere : and having thus imagined , can we conceive that all the vast space , or region circumscribed by the concave superfice of the lunar sphere , would not remain the same , in all its dimensions , after as before the reduction of all bodies included therein to nothing ? undoubtedly , that conceipt cannot endure the test of reason , which admits , that this sublunary space can suffer any other alteration , but only a privation of all bodies that possessed it . now , that it can be no difficulty to god , at pleasure , to adnihilate all things comprehended within it ; and yet at the same time to conserve the sphere of the moon entire and unaltered : cannot be doubted by any , but those inhumane ideots , who dare controvert his omnipotence . nor can it advantage our dissenting brother , the peripatetick to plead ; that we suppose , what ought not to be supposed , an absolute impossibility , as to the firm and fundamental constitutions of nature , which knows no such thing , as adnihilation of elements : since , though we allow it impossible to nature , yet can no man be so steeled with impudence , as to deny it facile to the author and governour of nature ; and should we conced it impossible to him also , yet doth not the impossibility of any effect interdict the supposition thereof as possible , in order to the appropinquation of a remote , and explanation of an obscure verity , nor invalidate that illation or assumption , which by genuine cohaerence depends thereupon . besides , 't is no novelty , nor singularity in us , upon the same consideration , to suppose natural impossibilities : insomuch as nothing is more usual , nor laudable amongst the noblest order of philosophers , then to take the like course , where the abstruse condition of the subject puts them upon it ; and even aristotle himself hath been more then once our praecedent and exemplar therein . for , when he had demonstrated the necessity of the motion or circumgyration of the coelestial orbs ; he yet requires of us , that we suppose them to quiesce constantly : that so we may the more satisfactorily apprehend the truth of that position , at which his whole discourse was collineated ; viz. that the cause of the earths quiet is not , as some dreamed , the rapid motion of the heavens ; for , having cleared the eye of his readers mind from all the dust of praesumption , with this supposition he th●n with advantage demands of him , ubinam terra moraretur ? ( de caelo . ) nay , even concerning this our argument , need we not want the authority of aristotle to justifie the lawfulness of this our supposition : for , attempting to enforce , that in a large imagined vacuum , in part whereof a cube of wood is conceived to be situate , there can be no dimensions but those of the cube ; he admits them conceiveable as clearly abstracted from the mass or bulk of wood , and devested of all corporeal accidents ; wh●●ein ( under favour ) he more then seems to incurr an open contradict●●● of his own dear tenet , that it is absurd to imagine any dimensions incorporeal . nor is the facility of our supposition less manifest then the lawfulness thereof : since we dare our opponents to produce any contemplat●ve person , who shall conscientiously attest , that he could not , when he fixed his thoughts thereupon , clearly and easily imagine the same ; what therefore can remain to impede our progress to the use , or scope of this our supposition ? having , therefore , imagined the whole sublunary region to be one continued and entire vacuum : we cannot but also imagine , that from any one point designed in the concave superfice of the lunar sphere , to another point ● diametro opposite in the same , there must be a certain distance , or intercedent space . if so ; must not that distance import a longitude , or more expresly an incorporeal and invisible line ? ( ) if so ; must not the medium of that line be the central point of the empty space , the same which stood for centre to the terraqueous globe , before its adnihilation ? ( ) if so ; may we not conceive how much of that voyd region was formerly possessed by the mass of elements : and with mental geometry commensurate how much of that space did once respond to the superfice , how much to the profundity of each of those bodies ? ( ) if so ; must we not allow the dimensions of longitude , latitude , and profundity imaginable therein ? undoubtedly , 〈◊〉 : since we can no where conceive a distance , or intercedent space , but we must there also conceive a quantum ; and quantity imports dimensions , nor is there any distance , but of determinate extent , and so commensurable . from the pressure of this socraticism , hath our peripatetick retreated to that ruinous sanctuary of the term , nothing : retarding our pursuit , with this sophism . when you suppose the sublunary region to be an absolute vacuum , you expresly concede , that nothing is contained therein ; and upon consequence , that those dimensions by you imagined therein , are nothing , and so that therein are no dimensions at all . why ; because dimensions consist essentially and so inseparably in quantity : and all quantity is inseparable from corporiety . wherefore , supposing no body existent in that empty space : you implicitely exclude all quantity , and consequently all dimensions from thence . this evasion , we confess , is plausible ; nor hath it imposed only upon young and paedantique praetenders to science , such as having once read over some epitome of the commentaries upon aristotles physicks , and learned to cant in scholastick terms ▪ though they understand nought of the nature of the things signified , believe themselves wise enough to rival solomon : but even many grey and sage enquirers , such who most sedulously digged for the jewel of knowledge in the mine of nature , and emancipated their intellectuals betimes from the slavery of books . for , among the most celebrated of our modern physiologists , we can hardly find two , who have judged it safer to abide the seeming rigour of this difficulty , then to run upon the point of this paradox ; that , if all bodies included in the ambite of the lunar heaven , were adnihilated , then would there be no distance at all betwixt the opposite sides of the same : and the reason they depend upon , is this ; necessary it is that those points should not be distant each from other , but be contiguous , betwixt which nothing doth intercede . nay , even des cartes himself cannot be exempted : since , 't is confest by him in princip . philosoph . articul . . ) that he subscribed the same common mistake , in these words : si quaeratur , quid fiet , si deus auferat omne corpus , quod in aliquo vase continetur , & nullum aliud in abluti locum subire permittat ? respondendum est vasis latera hoc ipso fore contigua . cum enim inter duo corpora nihil interjacet , necesse est , ut se mutuò tangant ; ac manifestè repugnat , ut distent , & tamen ut distantia illa sit nihil : quia omnis distantia est modus extensionis , & ideo sine substantia extensa esse non potest . to him also may we associate mr. white ( in dialog . . de mundo . ) the most direct and shortest way to the redargution of this epidemick errour , lyes in the detection of its grand and procatarctick cause ; which is the praeoccupation of most scholers minds by the peripatetick institutions , that limit our notions to their imperfect categories , and explode those conceptions as poetical and extravagant , that transcend their classical distinction of all entities into substance and accident . for , first , insomuch as in the dialect of the schools , those three capital terms , ens , res , aliquid , are mere synonyma's , and so used indiscriminately ; it is generally concluded , that whatever is comprehensible under their signification , must be referred either to the classis of substances , or that of accidents : and upon illation , that what is neither substance , nor accident , can praetend to no reality , but must be damned to the praedicament of chimaera's , or be excluded from being . again , having constituted one categorie of all substances , they mince and cantle out poor thin accident into nine , accounting the first of them quantity ▪ and subdividing that also into ( ) permanent , i. e. the dimensions of longitude , latitude , profundity ; and so make place to consist if not in all three , yet at least in one of them , viz. latitude or the superficies of a body : ( ) successive , i. e. time and motion , but especially time , which may be otherwise expressed by the term , duration . hereupon , when they deliver it as oraculous , that quantity is a corporeal accident : they confidently inferr , that if any quantity , or permanent , or successive , be objected , that is not or separately , or conjunctly corporeal , it ought to be exploded , as not real , or an absolute nothing . now this their scheme is defective . ( ) because it fails in the general distribution of ens , or res , into substance and accident : in regard , that to those two members of the division there ought to be superadded other two , more general then those ; viz. place and time , things most unreducible to the categories of substance and accident . we say , more general then those two ; because as well all substances as accidents whatever , have both their existence in some place , and their duration in some time ; and both place and time are , even by those who dispute whether they are accidents , or not , willingly granted to persever constantly and invariately the same . ( ) because it offends truth in the confinement of all quantity , or dimension , and so of that of place and time , to the category of accidents , nay even of corporeal ones : when there wants not a species of quantity , or extension having dimensions , that is not corporeal ; for , nor place , nor time , are corporeal . entities , being no less congruous to incorporeal , then corporeal beings . upon which consideration , 't is a genuine and warrantable inference ; that albeit place and time are not pertinent to the classis either of substances , or accidents : yet are they notwithstanding realities , things , or not-nothings ; insomuch as no substance can be conceived existent without place and time. wherefore , when any cholerick bravo of the stagirites faction , shall draw upon us with this argument ; whatever is neither substance , nor accident , is a downright nothing , &c. we need no other buckler then to except place and time. to authenticate this our schism , and assert our affirmation ; we must now evince , that place is neither accident , nor substance : which to effect , we need not borrow many moments of its twin-brother , time , to hunt for arguments in . for ( ) though it be objected , that place is capable of accession to , and sejunction from the locatum , without the impairment , or destruction thereof ; and in that relation seems to be a mere accident : yet cannot that justifie the consignation of place to the category of accidents ; because place is uncapable of access and recess , and 't is the locatum to which in right we ought to adscribe mobility . so that when various bodies may be successively situate in one and the same place , without causing any the least mutation therein : we must allow the force of this argument , to bring it nearest to the propriety of a substance . ( ) a substance it cannot be ; because the term , substance imports something , that doth not only exist per se , but also , and principally , what is corporeal , and either active or passive : and neither corporiety , nor activeness , nor passiveness , are attributes competent to place : ergo. now , to leave our roving , and shoot level at the mark ; the extract of these praemised considerations , will easily and totally cure the desperate difficulty objected . for , when it is urged , that betwixt the opposite sides of a vessel supposed to be absolutely devoyd of any body whatever , nothing doth intercede , and consequently that they are contiguous ; we need no other solution but this : that ( indeed ) nothing corporeal doth interced , betwixt the diametrally opposite sides of a voyd concave , that is either substance , or accident ; but yet there doth intercede something incorporeal , such as we understand by spatium , intercapedo , distantia , intervallum , dimensio , which is neither substance nor accident . but , alas ! that thing you call space is , according to your own supposition , an absolute vacuum : what though ? it must not therefore be nothing , unless in the sense of the peripatetick : because it hath a being ( suo modo ) and so is something . the same also concerns those dimensions , which we conceive , and the schools deny to be in our imaginary vacuum : for of them it may be likewise truly said , that they are nihil corporeum , but not that they are nihil incorporeum , or more emphatically , nihil spatiale , nothing spatial . hence , according to the distinction of things into corporeal , and incorporeal ; we may , on the design of perspicuity , discriminate dimensions also into ( ) corporeal , such as are competent to a ' body , wherein we understand longitude , latitude , profundity : ( ) spatial , such as are congruous to space , wherein we may likewise conceive longitude , latitude , and profundity . and so we may conclude , that those dimensions , which must remain in that supposed inane region circumscribed by the concave of the lunar orb , in case god should adnihilate the whole mass of elements , and all their off springs , included therein ; are , in truth , not corporeal , but spatial . let us skrew our supposition one pin higher , and farther imagine , that god , after the adnihilation of this vast machine , the universe , should create another , in all respects consimilar to this , and in the same part of space , wherein this now consisteth : and then shall our thoughts be tuned to a fit key for the speculation , nay the comprehension of three notorious abstrusities , viz. ( ) that as the spaces were immense , before god created the world ; so also must they eternally persist of infinite extent , if he shall please at any time to destroy it : that he , according to the counsel of his own beneplacit , elected this determinate region in the infinite spaces , wherein to erect or suspend this huge fabrick of the world ; leaving the residue which we call extramundan spaces , absolutely voyd : and that as the whole of this determinate region of space is adaequately competent to the whole of the world ; so also is each part thereof adaequately competent to each part of the world ; i. e. there is no part of the world , great or small , to which there is not a part of space exactly respondent in all dimensions . ( ) that these immense spaces are absolutely immoveable . and therefore should god remove the world into another determinate region of them , yet would not this space wherein it now persisteth ; accompany it , but remain immote , as now . in like manner , when any part of the world is translated from one place to another ; it leaves the part of space , which it formerly possessed , constant and immote , and the spaces through which it passeth , and wherein it acquiesceth , continue also immote . ( ● ) that , in respect the dimensions of these spaces are immoveable , and incorporeal : therefore are they every where coexistent , and compatient ( we speak in the dialect of the schools ) with corporeal dimensions , without reciprocal repugnancy ; so as in what part soever of space any body is lodged , the dimensions of that part of space , are in all points respondent to the corporeal dimensions thereof . in this case , therefore , 't is far from an absurdity , to affirm , that nature doth not abhor a penetration of dimensions . to bring up the rear of these advantages resulting from our supposition , we may from thence deprehend , why aristotle hath not cleft a hair in his position , that there is in the universe no interval , nor dimensions , but what are corporeal . to discriminate the incorporiety of these dimensions spatial , from that adscribed to the divine nature , intelligences angelical , the mind of man , and other ( if there be any ) incorporeal substances ; we advertise , that the term incorporeal bears a double importance . ( ) it intends not only a simple negation of corporiety , and so of corporeal dimensions ; but also a true and germane substance , to which certain faculties and operations essentially belong ; and in that sense it is adscriptive properly to god , angels , the souls of men , &c. spiritual essences . ( ) it signifies a mere negation of corporiety , and so of corporeal dimensions , and not any positive nature capable of faculties and operations ; and in this sense only is it congruous to the dimensions of space , which we have formerly intimated to be neither active , nor passive , but to have only a general non-repugnancy , or admissive capacity , whereby it receives bodies either permanentèr , or transeunt●r . here we discover our selves in danger of a nice scruple , deductive from this our description of space , viz. that , according to the tenor of our conceptions , space must be unproduced by , and independent upon the original of all things , god. which to praevent , we observe , that from the very word spatial dimensions , it is sufficiently evident , that we understand no other spaces in the world , then what most of our ecclesiastical doctors allow to be on the outside thereof , and denominate imaginary : not that they are meerly phantastical , as chimaera's ; but that our imagination can and doth apprehend them to have dimensions , which hold an analogy to the dimensions of corporeal substances , that fall under the perception and commensuration of the sense . and , in that respect , though we concede them to be improduct by , and independent upon god ; yet cannot our adversaries therefore impeach us of impiety , or distort it to the disparagement of our theory : since we consider these spaces , and their dimensions to be nihil positivum , i. e. nor substance , nor accident , under which two categories all works of the creation are comprehended . besides , this sounds much less harsh in the ears of the church , then that which not a few of her chair-men have adventured to patronize ; viz. that the essences of things are non-principiate , improduct , and independent : insomuch as the essence being the noblest , constitutive , and denominative part of any thing , substance or accident ; to hold it uncreat and independent , is obliquely to infer god to be no more then an adopted father to nature , a titular creator , and author of only the material , grosser and unactive part of the world. sect . ii. by the discovery of dimensions independent upon corporiety , such wherein the formal reason of space appears most intelligibly to consist , have we fully detected the weakness of aristotles basis , praeter dimensiones corporis locati , & ipsam ambientis superficiem , nullas alias dari : it remains only , that we demolish his thereupon-erected definition of place , in which his legions of sectators have ingarrisoned their judgments , as most impraegnable . that place is not the immediate and contiguous superfice of the body invironing the locatum , may by the single force of this demonstration be fully evicted . immobility is essential to place , as aristotle well acknowledged ; for if place were moveable , then would it follow of inevitable necessity , that a body might be translated without mutation of place , and è converso , the place of any thing might be changed , while the thing it self continues immote ; both which are absurdities so manifest , as no mist of sophistry can conceal them even from the purblind multitude : now the superfice of the circumambient can in no wise praetend to this propriety of place , immobility ; as may be most conveniently argued from the example of a tower ; for that space , which a tower possesseth , was there before the structure , and must remain there the same in all dimensions after the ruine thereof ; but the superfice of the contiguous aer , the immediate circumambient , is removed , and changed every moment , the whole mass of aer being uncessantly agitated more or less , by winds and other violences : ergo. so numerous are the shifts and subterfuges of the distressed disciples of aristotle , whereby they have endeavoured to fix this volatile superfice of the circumambient : that should we insist upon only the commemoration of them all ; we might justly despair of finding any charity great enough , to pardon so criminal an abuse of leasure . besides , from epicurus 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or space , we may extract salvo's for all those scruples , which are commonly met with by all , who worthily enquire into the nature of place . for , when it is questioned ( ) how a body can persist invariately in the same place , though the circumambient be frequently , nay infinitely varied ? ( ) how a body can change place , though the circumambient accompany it in its remove ? ( ) why one body can be said to be thus or thus far , more or less distant from another ? we may easily satisfie all with this one obvious answer , that all mobility is on the part of the locatum , all space continuing constant and immote . further , hence come we to understand , in what respect place is commonly conceived to be exactly adaequate to the locatum : for , the dimensions of all space possessed , are in all points respondent to those of the body possessing there being no part of the body , profound or superficial , to which there is not a part of space respondent in aequal extent ; which can never be made out from the mere superfice of the circumambient , in which no one of the profound or internal parts of the locatum , but only the superficial are resident . moreover , hence also may we understand , how incorporeal substances , as god , angels , and the souls of men , may be affirmed to be in loco . for , when god , who is infinite , and therefore uncapable of circumscription , is said to be in place ; we instantly cogitate an infinite space : which is more then we can do of place , if accepted in aristotles notion , which imports either that god cannot be in any place , or else he must be circumscribed by the contiguous superfice thereof : which how ridiculous , we need not observe . for angels likewise , who dares affirm an angel to be in a place , that considers his incorporiety , and the necessity of his circumsciption by the superfice of the circumambient , if aristotles definition of place be tolerable ? to excuse it with a distinction , and say , that an angel may be conceived to be in a determinate place , not circumscriptivè , but definitivè , i. e. so here , as no where else : is implicitely and upon inference , to confess the truth of our assertion ; since that here , designs a certain part of space , not the superfice of any circumambient . for , though you reply , that an angel , being an incorporeal substance , wants as well internal and profound dimensions , by which his substance may respond to space , as those superficial ones , that respond to place : yet cannot that suffice to an evasion , since if his substance hath any diffusion in place , as is generally allowed ; and though it be constituted in puncto , as is also generally conceived : nevertheless , doth that diffusion as necessarily respond to a certain aequal part of space , as a point is a determinate part of space . this perhaps , is somewhat abstruse , and therefore let us conceive an angel to be resident in some one point of that inane region circumscribed by the concave of the lunar orb , formerly imagined : and then we may without any shadow of obscurity understand , how his substance may respond to a certain part , or point of the inane space , so as he may be said to be here , not there , in this but no other place : but impossible it is , to make it out , how the substance of an angel constituted in puncto of an empty space , can respond to the superfice of a body circumambient , because all bodies formerly included in that sublunary region are praesupposed to be adnihilated . lastly , by the incorporiety of space we are praeserved from that contradiction , which aristotle endeavouring to praevent , praecipitated himself upon no small absurdity , viz. that the supreme heaven , or primum mobile is in no place . for , if we adhere to his opinion , that place is the superfice of a body circumambient ; the primum mobile being the extreme or bounds of the world , we deny any thing of corporiety beyond it , and so exempt it from locality : but if we accept space to be the same without and within the world , we admit the primum mobile , the noblest , largest , and most useful of all bodies in the world , to enjoy a place proportionate to its dimensions , and motion , as adaequately as any other . the necessity of which concession , thales milesius well intimated , when interrogated , what thing was greatest ? he answered , place : because , as the world contains all other bodies , so place contains the world. reduced to these straights , aristotle , among sundry other sophisms , entrusteth the last part of his defence , to this slight objection ; if place were a certain space , constant in three dimensions ; then would it inevitably follow , that the locatuus and the locus must reciprocally penetrate each others dimensions , and so the parts of each be infinitely divided : which is manifestly absurd , since nature knows nor penetration of dimensions , nor infinity of corporeal division . to this induction we could not refuse the attribute of probability , no more then we do now of plausibility , had we not frequently praevented it , and openly by our distinction of dimensions into corporeal and incorporeal , and appropriating the last to space . for , indeed , the fundamental constitutions of nature most irrevocably prohibite the substance of one body to penetrate the substance of another , through all its dimensions : but , alas ! place is ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) properly and altogether incorporeal ; and therefore may its dimensions incorporeal be coexistent , or compatient with the corporeal dimensions of any body , without mutual repugnancy , the spatial dimensions not excluding the corporeal , nor those extruding the spatial . this cannot be a diaphanous , or aenigmatical to those , who concede angels to be incorporeal , and therefore to penetrate the dimensions of any the most solid bodies , so that the whole substance of an angel may be simul & semel , altogether and at once in the same place with that of a stone , a wall , the hand of a man , or any other body whatever , without any necessity of mutual repugnancy . nor to those , who observe the synthesis , or collocation of whiteness , sweetness , and qualities in the substance of milk : for as those are conceived to pervade the whole substance of milk , without any reciprocal repugnancy of dimensions , so are we to conceive that the dimensions of space are totally pervaded by the whole body of the locatum , without renitency . chap. vii . of time and eternity . sect . i. some texts there are in the book of nature , that are best interpreted by the sense of the vulgar , and become so much the more aenigmatical , by how much the more they are commented upon by the subtile discourses of the schools : their over-curious descants frequently rendring that notion ambiguous , complex and difficult , which accepted in its own genuine simplicity , stands fair and open to the discernment of the unpraejudicate , at the first conversion of the a●●es of the mind thereupon . among these we have just cause to account time ; since if we keep to the popular and familiar use of the word , nothing can be more easily understood : but if we range abroad to those vast wildernesses , the dialectical paraphrases of philosophers thereupon , and hunt after an adaequate definition , bea●●ng its peculiar genus , and essential difference ; nothing can be more obscure and controversial . this the sacred doctor ( au●ust . . confess . . ) both ingenuously confessed , and most emphatically expressed , in his , si nemo 〈◊〉 me quaerat , quid sit tempus , scio ; si quaerenti explicare velim , nescio : intimating that the mind may , indeed , at first glance speculate the nature of time by a proper idea ; but so pale and fine a one , as 〈…〉 a lively representation thereof . 〈…〉 bold to list it among the most despe●●●● 〈…〉 generalitèr . to which we may annex 〈…〉 quoted by stobaeus ( eccl. phys. . ) tempus esse 〈…〉 non re , sed cogitatione constans . as also 〈…〉 who not only injoyns , that we discourse of time in a certain key of thought far different from that wherein we use to consider things , which have a real inhaerence in subjecto ; as if time had no other subject of inhaerence but the mind , were only a mere ens rationis , extrinsecal denomination , and could expect no exacter a description , then his numerus , qui absque ratione numerante est nullus : but adviseth , if any shall demand , what time is , to afford him no other but democritus answer ; tempus esse 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quale spatium diei noctisque apparet . if we research profoundly into the original of this difficulty , of acquiring a clear and perspect theory of the quiddity of time , from the lecture of those prolix treatises , whose plausible titles promise satisfaction concerning it : we shall soon find the chief cause to be this ; that most philosophers have praesupposed time to be some corporeal ens , or at least some certain accident inexistent in and dependent on corporeal subjects ; when ( in verity ) if it be any thing at all it seems to be the twin-brother of space , devoyd of all relation to corporiety , and absolutely independent on the existence of any nature whatever . for , to him , who shall , in abstract and attentive meditation , sequestre time from all bodies , from their motions , successive alternations , and contingent vicissitudes insequent upon those motions ; i. e. all years , months , weeks , dayes , hours , minutes , seconds , and all accidents or events contingent therein : it will soon appear most evident , that time ( in suo esse ) owes no respect at all to motion , its constancy , variety , or measure ; since the understanding must deprehend time to continue to be what it ever was and is , whether there be any motion or mutation in the world , or not , nay , whether there be any world or not . for , examining what is meant by the term duration , and what by the term motion , in their single importances apart : we discover , that motion holds no relation to duration , nor è converso , duration to motion , but what is purely accidental , and mental , i. e. imagined by man , in order to his commensuration of the one by the other . another cause of this difficulty , may be the irreconcileable discrepancy of judgments concerning it , even among the most venerable of the ancients . for ( ) epicurus hath a complex and periphrastical description of the essence of time , when he concludes it to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , an accident of accidents , or event of events , consequent to dayes and nights , and hours to passions and indolency , motion and quiet . the reason of which empiricus ( . advers . physic. ) by way of explanation , thus renders : days and nights are accidents supervenient upon the ambient aer , the one being caused by the praesence , the other by the absence of the sun ; hours are also accidents , as being parts of day or night ; but time is coextended to each day , night & hour , & therefore we say , that this day is long , this night short , while our thoughts are constantly pointing at time in that respect supervenient ; passions likewise and indolences , or dolours and pleasures , are accidents not without time evenient ; lastly , motion and quiet are accidents contingent in time , and therefore by it we commensurate the celerity and tardity of motion , the long or short duration of quiet : therefore is time the accident of accidents . and lucretius alluding to the same opinion of epicurus , translates his 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , tempus esse incorporeum , into tempus item per se non est , &c. lib. . ( ) zeno , chrysippus , apollodorus , posidonius , and their sectator philo , define time to be , motus coelestis , sive mundani intervallum , understanding as well all particular conversions , as the generality of motion from the beginning to the end of the world. whereupon philo would inferr , that time was coaevous to the world , i. e. before the world there was no time , nor should be any after : though the stoicks unanimously defend the infinity of time , in regard they affirmed an infinitie of worlds successive , the second springing up , phaenix-like , from the ashes of the first , the the third from the second , &c. ( ) pythagoras , according to the records of plutarch ( in quaestion . platonic . ) to one interrogating him concerning the essence of time , calls it animam coeli , the soul of heaven . to which plotinus ( en. . lib. . cap. . ) seems to have alluded , when interpreting plato's saying , that time was the image of eternity ( in timaeo ) he make ●ternity to be the very soul of the world , as considered in se , in its own simple essence ; and time to be the same soul of the world , considered , prout varias mutationes suscipit , as it admits various mutations . ( ) and aristotle , as every paedagogue hath heard , after a long and anxious scrutiny , positively and magisterially determines time to be , numerum motus ( coelestis ac primi ) secundum prius & posterius , the number of the first coelestial motion , according to former and later , i. e. insomuch as in motion we may observe parts antecedent and consequent by a perpetual succession . at the first word of this eminent definition , some superficial criticks have sawcely nibbled , urging ( forsooth ) that it sounds soloecistical , because number is quantity discrete , but time continued ; and therefore that the word measure ought to be its substitute : but alas ! had they read his whole discourse of the nature of time , they could not have been ignorant , that aristotle intended nothing less , then that time should be reputed a quantity discrete ; when both in his praecedent and subsequent lines he expresly teacheth , that motion is continued , in respect of magnitude , and time in respect of motion . had they excepted against the whole , indeed , their quarrel had bin justifiable , and our selves might safely have espoused it ; because , if time be the measure of coelestial motion , then must it follow , that if there were a plurality of worlds , or prima mobilia's ; there would also be a plurality of times , because a plurality of motions . to those of his disciples , who reply , that in case there were many first moveables , and consequently many distinct motions ; yet would there be but one measure of them all : we rejoyn , if it be supposed that some of the many motions are swifter then others , then of necessity must they have many prior and posterior parts ; and if so , how can all those , more or less discrepant in velocity and tardity , fall under one and the same measure ? or , what sober man can admit , that there would be but one time , where must be many distinct subjects of motion , and so of time ? nor can it more avail them to distinguish time internal from external , assigning to each particular primum mobile a proper or internal time within its ambite , and one general or external time to them all in common : because it is a manifest adynaton , that there should be a general time , without a general motion , whose parts being prior and posterior , in respect of perpetual succession , must be the common norma , or rule of observation to all the rest ; nor , indeed , can we admit , that a flux of ten hours at once , or together , is possible , where ten spheres are in one hour moved . and , therefore , though aristotle seems to have had some hint of the true nature of time , in his objection against those , who opinioned it to be coelestial motion : yet he lost it again , when he defined it to be the measure of coelestial motion . for , reason attesteth the contrary , it being evident that the coelestial motion is rather the measure of time : insomuch as the measure ought to be more known then the thing measured ; and time is a certain flux no less independent upon motion then quiet . which those worthies well understood , who confest time to be imaginary , such as flowed infinitely in duration before the creation , and shall continue its flux infinitely after the dissolution of the world. sect . ii. failing of satisfaction concerning the nature of time , from the definitions of others : it remains only , that we sedulously imploy our own cogitations in quest of some competent description of it . seneca ( in epist. . ) descanting upon plato's general distinction of all entities into six classes , saith thus ; sextum genus est eorum , quae quasi sunt , tanquam inane & tempus , the sixth genus contains only those things , which have as it were a being , as inanity and time : which we thus expound , space and time are things more general then to be comprehended under the categories of substance and accident . with this text we had not long exercised our thoughts , before we conceived , that the most hopeful way for exploring the mysterious quiddity of time , lay in the strict examen of the affinity or analogy betwixt it and the subject of our immediately praecedent chapter , space . nor did our conjecture prove abortive ; for , having confronted their proprieties in all points , we soon found their natures fully correspondent : so as the notion of one seems involved in that of the other ; as is manifest in this paralellism . ( ) as place , or space , in the total , is illimitate and immense : so is time , in its totality , non-principiate and interminable . ( ) as every moment of time is the same in all places : so is every canton or part of place the same in all times . ( ) as place , whether any , or no body be collocated therein , doth still persist the same immoveable and invariately : so doth unconcerned time flow on eternally in the same calm and equal tenor , whether any or nothing hath duration therein , whether any thing be moved or remain quiet . ( ) as place is uncapable of expansion , interruption or discontinuity , by any cause whatever : so is time uncapable of acceleration , retardation , or suspension ; it moving on no less , when the sun was arrested in the midst of its race in the dayes of ioshua , when the hebrews vanquished & pursued the amorrhites , then at any time before , or since . ( ) as god was pleased , out of the infinite space to elect a certain determinate region for the situation : so hath he , out of infinite time , elected a determinate part for the duration of the world. ( ) and therefore , as every body , or thing , in respect to its here or there , enjoyes a proportionate part of the mundane space : so likewise doth it , according to its now , or then of existence , enjoy a proportionate part of the mundane duration . ( ) as , in relation to place , we say , everywhere , and somewhere● so , in relation to time , we say , alwayes , and sometimes . hence , as it is competent to the creature to be only somewhere , in respect of place , and sometimes , in respect of time : so is it the praerogative of the creator , to be everywhere as to place , and forever , as to time . and therefore those two illustrious attributes , immensity , whereby he is praesent in all places , and aeternity , whereby he is existent at all times , are proper only to god. ( ) as place hath dimensions permanent , whereby it responds to the longitude , latitude , and profundity of bodies : so hath time dimensions successive , to which the motions of bodies may be adaequated . hence comes it , that as by the longitude , of any standing measure ( v.g. ) of an ell , we commensurate the longitude of place : so by the flux of an horologe do we commensurate the flux of time. and , insomuch as no motion is more general , constant and observed , then that of the sun : therefore do we assume its motion for a general horodix , by it regulate all our computations , and confide in it as an universal directory , in our mensuration of the flux of time. not that the feet of time are chained to the chariot of the sun , so as the acceleration or retardation of the motion of that should cause an equal velocity , or tardity in the progress of this : but that custom hath so praevailed , as we compute the flux of time by the diurnal and annual revolution of the sun. for , in case the motion of the sun were doubly swifter , then now it is , that of time would not therefore be doubly swifter also ; but only the space of two dayes would then be equal to the space of one , as now during the praesence of the sun to our hemisphere : nor , on the contrary , if the motion of the sun were doubly slower , would the pace of time be likewise doubly slower ; but only the space of one day , would be equal to that of two . and , therefore , he that will defend empedocles conceit , that in the beginning of the world , the length of the dayes did by six parts in seven exceed that of our dayes : must demonstrate that the urnal arch of the sun was then by six of seven larger then now , or its motion so much slower . from this paralellism 't is difficult not to conclude , that time is infinitely elder then motion , and consequently independent upon it : as also , that time is only indicated by motion , as the mensuratum by the mensura . for , insomuch as it had been otherwise impossible for man to have known how much of time he had spent either in action , or rest ; therefore did he fix his observation upon the coelestial motion , and compute the quantity of time pr●●terlapsed by the degrees of the suns motion in the heavens . and because the observation of the suns motion was easie and familiar ; therefore did the ancients invent several instruments , as water and sand hour-glasses , and sun-dials , and the neotoricks trochiliack horodixes , circumgyrated by internal springs , or external weights appensed ; and so artificially adaequated them to the motion of the sun , that defines the day by its praesence , and might by its absence , as having subdivided their horary motions into equal smaller parts , at last they descended to the designation of each step in the progress of time , i. e. to the computation even of minutes and seconds . if any yet doubt ( which we cannot suppose , without implicite scandal ) of the independence of time on coelestial motion ; or , that old chronos must stand still , in case the orbs should make a halt : we advise him seriously to perpend that supernatural detension of the sun in the day of battle betwixt the israelite and the amorrhite ; assuring our selves that his thoughts will soon light upon this apodictical argument . either there was no time during the cessation of the suns motion on that day ; or else time kept on its constant flux : for one of these positions must be true . that the first is false , is manifest from the extraordinary duration of the day , the text positively expressing , that no day was ere , nor should be so long as that ; and the word long undeniably importing a continued flux of time : ergo , the second must be most true ; and upon consequence , though the detention of the sun was miraculous , yet was the duration of the day natural , because time hath no dependence on coelestial motion . nor do they at all infirm the news of this dilemma , who object ; that there was then no time , because there were no hours : since hours are no more essential to time then spring , summer , autumn , and winter , which are only successive mutations of the temperament of aer , convenient to the conservation and promotion of seminalities ; and as for dayes , they likewise are absolute aliens to time , since while our hemisphere enjoyes the illumination of the sun , the subterraneous one wants it , and so our day is night to the antipodes inhabiting the opposite part of the globe terrestrial ; but time is constantly the same through the universe . besides , there were hours during the arrest of don phaebus ; in this respect , that the space of time , in which he stood still , was designable by the flux of hour-glasses , or any other temporary machine : nor ought we to say , there are no hours but those which we commensurate . and therefore , we incur no soloecism when we say , that god , had it seemed good in the eye of his wisdom , might have created the world many thousands of millions of years sooner then he did : because such was the praecedent flux of time as might be computed by spaces of duration in longitude respondent to that determinate space of time , which the sun in its progress through the zodiack annually doth fulfill ; not that before the creation , there were real years , distinct and defined by the repeated conversions of the sun. further , as time hath no dependence on , so can it receive no mutation from motion . aristotle , indeed , accuseth it of mutability , merely because we use to connect that time in which we fall asleep , to that in which we awake , losing that of which the cessation of our senses operation makes us insensible : but alas ! this looks like too weak a conceit to be the mature issue of so strong a brain as his ; insomuch as albeit we concede some mutations to be necessary , as to our perception of the flux of time , yet doth it not follow , that therefore those mutations are necessary ; as to the flux of time it self . true it is also , that we use to measure various mutations by time : but if we examine the matter profoundly , we shall animadvert , that the time , during which those mutations last , is rather measured by motion then the contrary ; for though that motion be not observed in the heavens , yet may it be aequivalent indicated by hour-glasses , or any other chronodix . which aristotle himself seems to acknowledge ( in . de coelo ) when he affirms , that as motion may be measured by time , so may time by motion . sect . iii. if time be , as our description imports , non-principiate and infinite : how can we discriminate it from aeternity ? should we resolve , that aeternity , in the ears of an unpraejudicate understanding , sounds no more then perpetual duration , or time that never knew beginning , nor can ever know an end : we are instantly assaulted with this difficulty ; that time hath dimensions successive , comprehends priority and posteriority of parts , and essentially consisteth in a certain perpetual flux ; but eternity is radicated in one permanent point , falls under none but the praesent tense , and is only a certain constant 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or intransible now ; or , as booetius defines it , interminabilis vitae tota simul & perfecta possessio , an interminable and perfect possession of life altogether , i. e. without praeterite and future , or , forever at once . to extricate our selves from this seeming confusion of two things , whose natures appear so irreconcileably disparate ; we are to begin at two praevious considerables . ( ) that plato ( out of whose timaeus that eminent definition of booetius was extracted , which hath received the approbation and praises of most of our ecclesiastick patriarchs ) asserting his opinion , that immutable and eternal natures are not subject to time , to which aristotle also assented ; doth not intend the word , aeternity , abstractly and praecisely , to signifie a species of duration : but concretely , for something whose duration is eternal , viz. the divine substance , which he otherwise calls , the soul of the world. this may be , without violence or sinister perversion , collected from hence , that he dislikes the incongruous conference of both and either of those tenses , fuit and erit , as well upon eternity or interminable duration , abstractly considered ; as 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , upon the eternal substance . and plotinus ( en. . lib. . cap. . ) more then once expresly declares as much : and most ingeniously insinuates the same both when he derives the word aeternity , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ab eo quod semper est ; and when he excludes all real alterity , or difference from 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quod est , and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quod semper est , importing that is and eternity are identical . ( ) that when plato denieth the congruity of praeterite and future , but allowes that of the praesent tense , or est , to the eternal substance ; he only aims at this , that , saying of the eternal substance , fuit , it hath been , we do not understand it the same with non amplius est , it is no more ; and also when we say of it , erit , it shall be , we do not understand it as nondum est , it is not yet : but not that fuit is incompetent to the eternal substance , provided we intend that it doth now continue to be the same it ever hath been ; nor erit , while we conceive it shall be to all eternity the same , that it ever hath been , and now is . it being manifest from the syntax and purport of all his dialogue , that his cardinal scope was only to praevent the dangerous adscription of those temporary mutations to the eternal being , which are properly incident to generable and corruptible natures : and to demonstrate , that we ought to conceive god , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , neque seniorem , neque juniorem . in a word , plato doth judge , that the tense est is proper only to the divine nature , because it is ever the same , or invariably possesseth the same perfections , nor is there any moment in the vast amplitude of eternity , wherein it can be justly said , now it hath some attribute , which it had not formerly , or which it shall not have in the future : since the progress of time can neither add any thing unto , nor detract any thing from it , as it doth to other natures , that are obnoxious to mutation ; so that god may well be called , in plato's phrase , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , habens se immobilitèr . these remora's of ambiguity removed , we may uninterruptedly advance to inference , and without further haesitancy determine , ( ) that when aeternity is said to be , quidpiam totum simul , something wanting succession or flux of parts , as in the memorable definition of booetius ; then is it to be accepted , not abstractly for duration , but concretely for the divine substance , whose duration is sempiternal . ( ) that time and eternity differ each from other , in no other respect , then that eternity is an infinite duration , and time ( according to the vulgar intent of the word ) a certain part of that infinite duration , commensing at the creation , and determining at the dissolution of the world. this cicero rightly apprehended , and emphatically expressed , in his sentence , tempus est pars quaedam aeternitatis , cum alicujus annui , menstrui , diurni , nocturnive spatii certa significatione . in this respect , eternity is said to be duration non-principiate and interminable ; which is proper only to god : and time is said to be duration principiate and terminable ; which is competent to all caduce , mutable , and corruptible natures : as also that part of eternity , which the neotericks by a special idiome name ●●vum , is duration principiate , but interminable , which is adscriptive to angelical or intellectual natures , and to the rational soul of man ; for thus we understand that frequent bipartition of eternity into à parte ante , & à parte post , invented by the schoolmen . these positions being indisputable , the remaining subject of our praesent disquisition , is only whether the platonicks spake rationally and intelligibly , when they defined eternity to be one everlasting now , or a duration void of succession , or flux of parts ? concerning this grand doubt , we profess , would truth have connived , we could most willingly have past it by untoucht ; because most of our christian doctors have fully assented unto them in this particular : but , since the convulsion of this their opinion doth stagger no principle of faith , or canonical document made sacred and established by the authority of the church ; we shall not deserve excommunication , nor suffer the expurgatory spunge of rome , if we quaestion the congruity of that definition , and affirm that no man can understand it . for , what wit is so acute and sublime , as to conceive , that a thing can have duration , and that duration can be as a point without fusion and continuation from one moment to another , by intervenient or mediate moments ? easie enough , we confess , it is to conceive , that the res durans is altogether at once , or doth retain the sameness of its nature , without mutation , diminution , or amission of any perfection : but that , in this perseveration , there is not many nows , or many instants , of which , compared among themselves , some are antecedent , and others consequent ; is to us absolutely incomprehensible . nor can we understand , why it may not be good christian phrase , to say ; god was in the time of the first man , and shall be in the time of the last : or why it is not more grammatical and proper for us to say , god created the world heretofore , and will both destroy and renovate the world hereafter ; then , that god doth now create , destroy and renovate . to this the common answer is , that the reason why these anthropopathical phrases are tolerable , is because eternity is coexistent to our time ▪ but this is ignotum explanare per ignotius ; for the manner of that supposed coexistence hath been never explained , and seemeth ●aid by till the advent of elias . that an instant , i. e. what wants succession , can be coexistent to a successive thing ; is as manifest an impossibility , as that a point , i. e. what wants longitude , can be coexistent or coextensive to a line . indeed , they have endeavoured to wave the difficulty , by subnecting , that the instant of eternity is of such peculiar eminency , as that it is aequivolent to time though successive : but as to the formal reason , and manner of this peculiar eminency , they have left it wholly to our enquiry also . nor did they bestow one serious thought upon the consideration of it ; for had they , doubtless they must have found their wit at a loss in the labyrinth of fancy , and perceived themselves reduced to this exigent : either that they had fooled themselves in trifling with words not well understood ; or that they had praecariously usurped the quaestion ; or that the same instants are in eternity , that are in our time , but with such eminency , that infinitely more are contained in eternity , then in our time. how much better were it said , that we are coexistent with god ; or , that we are existent in a small part of that duration , in which god infinitely existeth ? for , while we are , certainly , we cannot imagine two distinct durations ; but one , which in respct to our nature , that is principiate , mutable , and terminable , doth contain designable terms ; and in respect of the divine nature , which is nonprincipiate , immutable , interminable , hath its diffusion or extension infinitely long before , and as long after us . this may receive ample justification from that speech of the hebrew poet , whose inspirer was the holy ghost , ( psal. . ) thou shalt change them and they shall be changed ; but thou , o god! art the same forever , and thy years shall not fail . for here years are attributed to god , but not any mutation of substance : so that when our years are exhausted , in a short , or span-like flux of time , the glass of his duration is alwayes full . and , therefore , the expression is only tropological , when it is said , that the years of our life make but a day in the almanack of divinity : for the life of the hemerobii compared to ours of threescore years and ten , holds some proportion ; but the life of methusalem , compared to the duration of the life of our lives , the divine essence , holds none at all . upon this consideration , it was more then a heathen observation of plutarch ( in consolat . ad apollon . ) that there is no difference betwixt a long and a brief time , in respect of eternity : since , as simonides , a thousand , nay a million of years make but a point , nor so much as the least part of a point in the line of infinite duration . convicted thus by reason , our doctors convert to scripture , urging that god ( exod. . ) indicates his beeing only in the praesent tense , as peculiar to his eternity , saying , i am , that i am , and i am hath sent thee to moses . but this objection admits of a threefold evasion . ( ) the hebrew text doth not , in that place , use the praesent , but the future tense , i shall be , what i shall be , and i shall be hath sent thee . ( ) we can oppose many other texts , which adscribe to god as well praeterite and future , as praesent time ; and most eminently in the revelation , he is described , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , he that is , and was , and is to come . ( ) god himself doth frequently enunciate many actions , not that he now doth , but that he hath formerly done , and will do in the future , in that moment of opportunity , which his wisdom hath praedetermined . hence also expulsed , they fly to their last fortress , viz. if eternity be not one permanet now , then cannot all things be praesent to god , objectively . but vain is their hope of security in this also . for , many things , if we respect the when of their existence , have already been , and as many are not yet ; but , because the omniscience of god pervades as well the darkness of past , as of praesent time , and alwayes speculates all things most clearly and distinctly therefore do we say , that all things are objects to his opticks , or , that all things are praesent to his cognition ; not that he knows , all things to be praesent at once altogether , but that he hath before him at once all the diversities of times , and as perfectly contemplates them future and praeterite , as praesent . for , the divine intellect doth not apprehend objects , as the humane , one after another , or in a successive and syntactical series ; but grasps all things together in one entire act of cognition , and comprehends in one simple intuition whatever hath been , or may be known . and , therefore , our opinion is not at all impugned by that sacred sentence ; all things are open and naked to his eyes , and he calls upon those things , that are not , as if they were hereupon some have , with unpardonable temerity and incogitancy , inferred ; that once there was no time ; for in this their very denial , they openly confess , that time hath ever been : it being all one as if they had said , there was a time when there was no time. lastly , as the omniscience of god cannot be indubitated by our persuasion of the identity of eternity and time , so neither can his immutability , as aristotle would have it , only for this reason ( forsooth ) that time , or that duration , which hath successive , and so prior and posterior parts , is the general cause of corruption . for , our praecedent discourse hath left no room for the intrusion of that futile objection ; insomuch as it rather commonstrateth the divine nature to be so constant and perfect , that in the eternal flux of time it can know nothing of innovation or corruption . besides , time , or the succession of duration , is not the cause , that induceth corruption : but the native imbecillity of compound natures , invaded and subdued by some contrary agent ; and god is a pure , simple , homogeneous substance , and so not subject to the invasion of any contrary . evident it is , therefore , that aristotle , when he urged this sophism , spoke more like a poet , then a philosopher ; since poets only use to give time the epithite of edax rerum : nor could he be so absurd , as to dream , that time was a vast animal , with sharp teeth , an insatiate appetite , and a belly inexplebile , or an old man armed with a sithe , as the poets describe saturn , making 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , saturn and time one and the same thing . for , time really doth neither eat nor mow down any thing ; and the dissolution of all create compound natures can be imputed to no other cause , but the domestick hostility of their heterogenieties , or the uncessant intestine warr of their elements , from whose commixture their compositions , or concretions did first result . with this qualification , therefore , we are not angry at that of periander , in stobaeus , tempus est causa omnium rerum : because in the process of time all things have their origin , state , and declination . in this restrained sense we also tolerate the saying of thales milesius , quoted by laertius , tempus est sapientissimum : since time produceth experience , and experience prudence . and that antitheton of pharon the pythagorean , recited by aristotle ; tempus est ineruditissimum : because in process of time the memory of all things is obliterated , and so oblivion may well be called the hand-maid of time , that perpetually follows at the heels of her mistriss . our clue of thoughts concerning time is now wholly unravelled ; and though we may not praesume , that we have therewith led the mind of our reader through all the mysteries of its nature : yet may we hope , that it may serve as a conduct to those , who have a more ample stock of learning and perspicacity for the support and encouragement of their curiosity ; at least that the attentive and judicious may easily collect from thence , that we have , upon no interest but that main one of verity , withdrawn our assent from the common doctrine of the schools , that eternity is one permanent now , without succession , or priority and posteriority of moments . the second book . chap. i. the existence of atoms , evicted . sect . i. among infinite other hypochondriack conceits of the teutonick ( rather , fanatique ) philosophers , they frequently adscribe a dark and a light side to god ; determining the essence of hell in the one , and that of heaven in the other . whether the expression be proper and decent enough to be tolerated ; requires the arbitration of only a mean and vulgar judgment . we shall only affirm , that had they accommodated the same to the shadow , or vicegerent general of god , to nature ; their dialect had been , as more familiar to our capacity , so more worthy our imitation . for , that the incorporeal , and therefore invisible part of the universe , the inane space , may bear the name of the dark ; and the corporeal and visible part of the luminous side of nature : seems consentaneous to reason . on the first , hath the eye of our mind been thus long levelled ; taking in by collateral and digressive glances the essential proprieties of place and time ; the one of which is absolutely identical , the other perfectly analogous to inanity : on the other we are now to convert it , and with more then common attention , therein to speculate the catholique principles , motions and mutations , or generation and corruption of bodies . all bodies , by an universal distinction , are either ( ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , such , from the convention and coalition of which all concretions result ; familiarly called by physiologists , principia , primordia , componentia , but most commonly , elementa , and materia prima . or ( ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , such as consist of the former coacervated , and coalesced : or such as are composed of many single particles component . the former were made by creation , and are superiour to corruption : the later are produced by generation , and reducible by corruption . the first are simple and originary ; such as plato intends ( in phaedro ) when he saith , principii nullam esse originem , quoniam ex ipso principio oriuntur omnia : the other , compound and secondary ; such as lucretius ( lib. . ) understands by his concilio quae constant principiorum . what these first , simple , ingenerable , incorruptible , universally component bodies are , or to speak in the dialect of the vulgar , what is the general matter of all concretions ( it is no soloecism in physiology , to transfer a word abstractly importing a natural action upon the thing produced by that action ) hath been by more disputed , then determined , in all academies . that there must be some one catholique material principle , of which all concrete substances are composed ; and into which they are again , at length by corruption resolved : is unanimously confessed by all . and , consequently , that this matter is incorruptible , or the term wherein all dissolution ceaseth ; hath been indubitated by none , but those , who , upon a confusion of geometrical with physical maxims , run upon the point of that dangerous absurdity , that the infinite division of a real continuum is possible . insomuch therefore , as the essential reason or formality of corporiety doth solely consist in extensibility , or the dimensions of longitude , latitude , and profundity real ; as our third chapter praecedent hath demonstrated , and as the patriarch of the schools doth expresly confess ( natur. auscult . . cap. . ) and insomuch as nothing can be the root or beginning of material or physical extension , but 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , aliquid indissolubile , something so minute and solid , that nothing can be conceived more exiguous and impatible in nature ( for , as the radix of mathematick , or imaginary continuity , is a point : so must that of physical or sensible continuity be a body of the smallest quantity ) such as are the atoms of democritus , epicurus , and other their sectators ; and the insensible particles of cartesius : therefore , from manifest necessity , may we determine , that no principle can justly challenge all the proprieties , or attributes of the first universal matter , but 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , indivisible bodies , or atoms . which fundamental position clearly to establish by demonstration ; is a chief part of our difficult province : having , for method and prevention of obscurity , first briefly insisted upon their various appellations , with the etymological relation of each , traced them up to their 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or invention , and evicted their existence . ( ) as for their various denominations ; they naturally reduce themselves to three general imports , bearing a congruous and emphatick respect to their three most eminent proprieties . for , ( ) in relation to their corporiety , they are called , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , bodies , by way of transcendency : because they are 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , devoyd of all incorporiety , i. e. they contain nothing of inanity , as do all concretions emergent from them , there being in all compound bodies more or less of inanity disseminate among their particles . for which reason , they are also named , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , plena . ( ) in regard of their affording matter to all concretions , they are denominated , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , principles , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , elements , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , first bodies , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , first magnitudes , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , the matter of all things , and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , genitalia semina rerum , the seminaries of all productions : because all material things are composed of them . in which concern also , by a pythagorical epithite , they are s●●led , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , unities ; because , as all numbers arise from unities , so all compositions from them . ( ) to denote their indissolubility , they are most frequently known by the term , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , atoms ; either because they are incapable of section , as isodor , plutarch , servius , budaeus , scapula , &c. or 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ob indissolubilem soliditatem , for their indissoluble solidity . for , all concrete bodies , insomuch as they came short of absolute solidity , having somewhat of inanity intermixt , may be divided , and subdivided until their ultimate resolution into these , their component parts : but atoms admit of no division below themselves . wherefore they are usually christned , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , individual , insectile , impartible ; as likewise , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , invisible , and by the mind only perceptible , bodies , i. e. so exile as no man can conceive a real exility beyond theirs . hence are we assured , that two vulgarly passant derivations of the word , atome , are ingenuine and extorted . ( ) that of hesychius , with too much semblance of approbation mentioned by the reviver of the great democritus , magnenus , ( de atom . disput . . cap. . ) which would have it a sprigg of that root , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , fumus ; because ( forsooth ) from all bodies , in their reversion from mix●ion to dissolution , their elements disperse by exhalation : as if this etymologie were so adaequate and important , as to compensate the de●ect o● an omicron , in the second syllable . ( ) that embraced not only by many paedantique grammarians , but even acute philologers , who interpret the word atomus to signifie a defect of parts ; as if an atom were destitute of all magnitude , or no other then a mere mathematical point : when , indeed , the nomenclator had his eye fixt only on their solidity , ha●dness , or impatibility , which is such , as excludes all possibility of fraction , section , division . thus much epicurus himself expresseth , in most persp●cuous and unpervertible terms ( apud plutarch . . pla●●t . . ) thus ; dicitur atomus , non quòd minima sit , vel i●star puncti , sed quod non possit dividi ; cùm sit patiendi incapax , & inanis expers . and galen ( de elem. ) recounting their doctrine , who affirmed the principles of all bodies to be atoms , s●ith of epicurus , fecit atomos , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , he made them infrangible in respect to their solidity . ( ) concerning their invention ; if we reflect upon them as in re , before their reception of any constant denomination ; we have the tradition not only of possidonius the stoick , related by empiricus ( advers . physic. lib. ib. ) but also of strabo , to assure the honour thereof upon one moschus , a phoenician , who flourished not long before the ruine of troy by the graecians . allowing this for authentique , we have some cause to judge magnenus to have been too favourable to his grand master , democritus , when ( in testimon . de democrito . pag. ● . ) he enricheth his panegyrick of him with , effluvia corporum atomosque comperit , & invexit omnium primus : ex laertio quod unum tanti apud me est , ut congestas omnium philosophorum laudes vel exaequet vel superet . besides , to do laertius right , he finds leucippus , not democritus , to have been the founder of this incomparable hypothesis : as his records lye open to testifie ( in vita leucippi . ) but , if we reflect upon them only as in nomine , enquiring who was their godfather , that imposed the most convenient name , atoms , upon them ; we need not any more ancient , or faithful monuments to silence all competition about that honour , then those of theodoret : who rightly sets the laurel on the deserving front of epicurus , in this text ; 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ; epicurus , neoclis filius , dicta illis ( meaning democritus and metrodorus chius ) nasta & adiaereta , appellavit atomos . we are not ignorant , that sidonius apollinaris ( carmin . . ) adscribes the imposition of this name , to archelaus in these verses : post hos , archelaus divina , mente paratam concipit hanc molem , confectam partibus illis , quos atomos vocat , ipse leveis &c. but how unjustly , even s. augustine ( . de civit. dei , cap . ) sufficiently declares ; saying , that archelaus deduced all things , non ex atomis , sed ex particulis dissimilibus . and therefore , though we may not file up the first discovery of this noble principle , atoms ( of all others , hitherto excogitated , the most verisimilous , because most sufficient to the solution of all natures phaenomena ) among those many benefits , which the commonweal of philosophy owes to the bounteous wit of epicurus : yet hath his sagacity in accommodating them with so perfectly congruous an appellation , and successful industry in advancing and refining their theory , in the general , worthily entituled him to the homage of a grateful estimation equal to that , which the merit of their inventor claims . ( ) concerning their existence ; that there are such things , as atoms , or insectile bodies , in rerum natura ; cannot be long doubted by any judicious man , who shall thus reason with himself . ( ) nature can produce nothing out of nothing ; nor reduce any thing to nothing : is an axiome , whose tranquility was never yet disturbed , no not by those who hav● invaded the ●ertitude of even first notions , and accused geometry of delusion . if so ; there must be some common stock , or an universal something , ingenerable , and incorruptible , of which being praeexistent , all things are generated , and into which being indissoluble , all things are , at the period of their duration , again resolved . that nature doth dissolve bodies into exceeding minute , or insensible particles ; her self doth undeniably manifest , as well in the nutrition of animate ( their aliment being volatilized into so many insensible particles , as those whereof the body nourished doth consist ; otherwise there could be no general apposition , accretion , assimilation ) as the incineration of ●ead bodies . which ground des cartes rightly apprehended to be so firm and evident , that he thought the existence of his insensible particles sufficiently demonstrable from thence . quis dubitare potest ( saith he ) quin multa corpora sint tam minuta , ut ea nullo sensu deprehendamus , si tantum consideret , quidnam singulis horis adjiciatur iis quae lente augentur , vel quid detra●atur ex iis quae sensim minuuntur ? cresci● enim arbor quotidiè , nec potest intelligi majorem illam reddi quam prius fuit , nisi simul intelligatur aliquod corpus eidem adjungi . quis autem unquam sensu deprehenderit , quaenam sint illa corpuscula , quae in una die arbori crescenti accesserunt , &c. ( princip philos. part . . articul . . ) that she cannot in her dissolution of bodies , proceed to infinity , but must consist in some definite term , or extreme , the lowest of physical quantity ; is demonstrable from hence , that every real magnitude is uncapable of interminable division . for , since to an infinite process is required an infinite time ; she could never generate any thing new , because the old would require an infinite time and process to their dissolution . convicted by this apodictical argument , aristotle ( phys. . ) detesting the odious absurdity of ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) running on to infinity ; solemnly concludes ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) that there must be an extreme matter , wherein all exolution is terminated : only herein he recedes from the supposition of democritus , epicurus , and other patrons of the same doctrine that they terminated all exolution in the insectility of atoms ; but he describes no such extreme , or point of consistence , his materia prima being stated rather potential , then actual , and absolutely devoid of all quantity ; then which we know no more open and inexcusable a contradiction . again , if the exolution of bodies were not definite , and that nature knowing no n● ultra , did progress to adnihilation : then must it inevitably follow , that the matter of all things , that have been formerly , is totally adnihilated ; and the matter of all things now existent , was educed out of nothing . two most intolerable absurdities ; since adnihilation and creation are terms n●t to be found in the dictionary of nature , but proper only to omnipotence : nor is there any sober man , who doth not understand the common material of thi●gs to be constantly the same , through the whole flux of time , or the duration of the world ; so as that from the creation thereof by the fiat of god , no one particle of it can perish , or vanish into nothing , until the total dissolution of nature , by the same metaphysical power ; nor any one particle of new matter be superadded thereto , without miracle . the energy of nature is definite and praescribed : nor is she commissioned with any other efficacy , then what extends to the moulding of old matter into new figures ; and so , the noblest attribute we can allow her , is that of a translator . now , to extract the spirit of all this , since there must be an extreme , or ultimate term of exolubility , beyond which can be progress ; since this term can be conceived no other but the lowest degree of physical quantity ; and since , beyond the in●ectility of atoms , no quantity physical can be granted : what can the genuine consequent be , but that in nature there are extremly minute bodies , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , indivisible and immutable ? ( ) for confirmation ; as in the universe there is , aliquid inane , something so purely inane , as that it is absolutely devoyd of all corporiety : so also must there be aliquid corporeum , somewhat so purely corporeal , or solid , as to be perfectly devoyd of all inanity ; to which peculiar solidity nothing but atoms , in regard of their indivisibility , can praetend : therefore is their existence to be confessed . this reason lucretius most elegantly thus urgeth ; tum porrò ▪ si nil esset , quod inane vacaret , omne foret solidum ; nisi contrà corpora caeca essent , quae loca complerent quaecunque tenerent , omne quod est spatium , vacuum constaret inane , &c. lib. . ( ) evident it is to sense , that in the world are two sorts of bodies , soft and hard ; now , if we assume the principles of all things to be exquisitely hard , or solid ; then do we admit the production of not only hard , but also of soft bodies to be possible , because softness may arise to a concretion of hard principles , from the intermistion of inanity : but , if we assume soft principles , then do we exclude all possibility of the production of hard bodies , that solidity , which is the fundament of hardness , being substracted : therefore is the concession of atoms necessary . ( ) nature is perpetually constant in all her specifical operations , as in her production and promotion of animals to the determinate periods of their increment , stature , vigour , and duration ; and , more evidently , in the impression of those marks , whereby each species is discriminated from other . now , to what cause can this her constancy be , with greater probability , referred then to this , that her materials are certain , constant , and inobnoxious to dissolution , and consequently to mutation : and such are atoms praesumed to be ? ergo , they are existent . chap. ii. no physical continuum , infinitely divisible . sect . i. the grand base on which the whole fabrick of the atomists , i. e. our physiology is supported , confesseth it self to be this ; that nature cannot extend her dissolution of bodies beyond 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , somewhat that is firm and inexsoluble . and the rock on which that adamantine base is fixt , is soon understood to be this ; that the parts of no physical continuum , or magnitude , are subdivisible to infinity . the former , we conceive so clearly comprobated by reasons of evidence and certitude equal to that of the most perfect demonstration in geometry , that to suspect its admission for an impraegnable verity , by all , who have not , by a sacramental subscription of aristotles infallibility , abjured the ingenious liberty of estimating philosophical fundaments more by the moments of verisimility , then the specious commendums of authority ; were no less then implicitely to disparage the capacity of our reader , by supposing him an incompetent judge of their importance and validity . and that the other is equally noble in its alliance to truth , and so secure from subversion by the minds of the acutest sophistry , that may oppose it ; is the necessary theorem of this praesent exercitation . to usher in this verity with the greater splendor , we are required to advertise ( ) that philosophers have instituted two distinct methods , for the regular division of magnitude . for , their divisions are continued by a progression through parts either ( ) proportional ; which is when a physical continuum is divided into two parts , and each of those parts is subdivided again into two more , and each of those into two more ; or when the whole of any magnitude is divided into equal parts , and each of those into more , and each of those into more , and so forward , observing the same decimal proportions through the whole division : or ( ) aliquotal ; i. e. when a continuum is divided into such parts , as being divers times repeated , are aequated to the whole , or into so many parts as seem convenient to the divisor , provided they hold equal proportions among themselves , whether they be miles , furlongs , fathoms , feet , digits , &c. which distinction aristotle seems to allude unto , when he declares ( . physic . . ) that the difference betwixt magnitude and number doth consist in this , that by the division of numbers we arrive at last , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ad minimum , at the least ; but of magnitude , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ad minus , only to a less . ( ) that when democritus , epicurus , and other ancients of the same antistoical faction , treating of the division of magnitude , determine it 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ; they did chiefly intend that methodical division , which is made in partes proportionales ; insomuch as every part made by a second division must be less then that made by a first . the demonstration . if in a finite body , the number of parts , into which it may be divided , be not finite also ; then must the parts comprehended therein be really infinite : and , upon consequence , the whole composition resulting from their commixture , be really infinite ; which is repugnant to the supposition . so perfectly apodictical , and so inoppugnably victorious , is this single argument , that there needs no other to the justification of our instant cause : nor can the most obstinate and refractory champion of the peripateticks , refuse to surrender his assent thereto , without being reduced to a most dishonourable exigent . for , he must allow either that the whole of any body is something besides , or distinct from the aggeries , or mass of parts , of which it is composed : or , that all the parts , together taken , are somewhat greater then the whole amassed by their convention and coalescence . if so ; there must be as many parts in a grain of mustard seed , as in the whole terrestrial globe : since in either is supposed an equal inexhauribility ; which is contrary to the first notion of ●uclid , totum est majus sua parte . and if any mans skull be so soft , as to admit a durable impression of an opinion so openly self-contradictory , as this , that the whole is less then its parts ; we judge him a fit scholer for chrysippus , who blusht not publiquely to affirm , that one drop of wine was capable of commistion with every particle of the ocean , nay , diffusive enough to extend to an union with every particle of the universe , were it ● times greater , then now it is . nor , need we despair to make him swear , that arcesilas did not jeer the disciples of zeno , when he exemplified the inexhaurible division of magnitude , in a mans thigh , amputated , putrified , and cast into the sea ; ironically affirming the parts thereof so infinitely subdivisible , that it might be incorporated per minimas , to every particle of water therein ; and consequently , that not only antigonus navy might sail at large through the thigh , but also that xerxes thousand two hundred ships might freely maintain a naval fight with gallies of the greeks , in the compass of its dispersed parts . we deny not , but zeno's argument against motion , grounded on the supposition of interminable partibility in magnitude , is too hard and full of knots , to be undone by the teeth of common reason : yet who hath been so superlatively stupid , as to prefer the mere plausibility thereof to the contrary demonstration of his sense , and thereupon infer a belief , that there is no motion in the world ? what credulity is there so easie , as to entertain a conceit , that one granule of sand ( a thing of very small circumscription ) doth contain so great a number of parts , as that it may be divided into a thousand millions of myriads ; and each of those parts be subdivided into a thousand millions of myriads ; and each of those be redivided into as many ; and each of those into as many : so as that it is impossible , by multiplications of divisions , ever to arrive at parts so extremely small , as that none can be smaller ; though the subdivisions be repeated every moment , not only in an hour , a day , a month , or a year , but a thousand millions of myriads of years ? or , what hypochondriack hath been so wild in phansie , as to conceive that the vast mass of the world may not be divided into more parts then the foot of a handworm , a thing so minute as if made only to experiment the perfection of an engyscope ? and yet this must not be granted , if we hearken to the spels of zeno and the stoicks ; who contend for the divisibility of every the smallest quantity into infinite parts : since , into how many parts soever the world be divided , as many are assumable in the foot of a hand-worm , the parts of this being no less inexhaustible , nor more terminable by any continued division , then the parts of that , according to the supposition of infinitude . and , hereon may we safely conclude , that albeit the arguments alledged in defence of infinite divisibility of every physical continuum , were ( as not a few , nor obscure clerks have reputed them ) absolutely indissoluble : yet notwithstanding , since we have the plain certificate of not only our reason , but undeluded sense also to evidence the contrary , ought we to more then suspect them of secret fallacy and collusion ; it being a rule , worthy the reputation of a first notion , that in the examination of those physical theorems , whose verity , or falsity is determinable by the sincere judicature of the sense , we ought to appeal to no other criterion , but to acquiesce in the certification thereof ; especially where is no refragation , or dissent of reason . notwithstanding the manifest necessity of this apodictical truth , yet have there been many sophisms framed , upon design to evade it : among which we find only two , whose plausibility and popular approbation seem to praescribe them to our praesent notice . the first is that famous one of aristotle ( de insecabil . lineis ) non creari propterea infinitum actu ex hujusmodi partibus infinitis , quoniam tales partes non actu , sed potestate duntaxat infinitae sunt ; adeo proinde ut creent solùm infinitum potestate , quod idem sit actu finitum : that the division of a finite body into infinite parts doth not make it actually infinite , because the parts are not actually , but only potentially infinite ; so as they render it infinitely divisible only potentially , while it still remains actually finite . the collusion of this distinction is not deeply concealed . for , every continuum hath either no parts in actu , or infinite parts in actu . since , if by parts in actu , we understand those that are actually divided : then hath not any continuum so much as two or three parts ; the supposed continuity excluding all division . and if we intend , that a continuum hath therefore two parts actually , because it is capable of division into two parts actually : then is it necessary , that we allow a continuum to have parts actually infinite , because we presume it capable of division into infinite parts actually ; which is contradictory to aristotle . nor can any of his defendants excuse the consequence by saying ; that the division is never finishable , or terminable , and that his sense is only this , that no continuum can ever be divided into so many parts , as that it may not be again divided into more , and those by redivision into more , and so forward without end . since , as in a continuum two parts are not denyed to exist , though it be never divided into those two parts : so likewise are not infinite parts denied to exist therein , though it be never really divisible into infinite parts . otherwise , we demand , since by those requisite divisions and subdivisions usque ad infinitum , still more and more actuall parts are discovered ; can you conceive those parts , which may be discovered to be of any determinate number , or not ? if you take the affirm . then will not there be parts enough to maintain the division to infinity : if the negat . then must the parts be actually infinite . for , how can a continuum be superior to final exhaustion , unless in this respect , that it contains infinite parts , i. e. such whose infinity makes it inexhaustible . because , as those parts , which are deduced from a continuum , must be praeexistent therein before deduction ( else whence are they deduceable ? ) so also must those , which yet remain deduceable , be actually existent therein , otherwise they are not deducible from it . for , parts are then infinite , when more and more inexhaustibly , or without end , are conceded deducible . the other , with unpardonable confidence insisted on by the stoicks , is this ; continuum non evadere infinitum ; quoniam illud propriè resultat non ex proportionalibus , sed ex aliquotis partibus , quas constat esse definitas , cùm inter extrema corporis versentur : that [ by admitting an infinity of parts in a finite continuum ] a continuum doth not become infinite ; because that results properly not from proportional , but aliquotal parts , which are therefore confess'd to be definite , because they relate only to the extremes of a body . first , this subterfuge is a mere lusus verborum , sounding nought at all in the ears of reason . for since every thing doth consist of those parts , into which it may be at last resolved ; because every continuum is at last resolved into , therefore must it con●ist of proportional parts . again , since every one of aliquotal parts is continuate , each of them may be divided into as many aliquotal parts , as the whole continuum was first divided into , and so upwards infinitely : so as at length the division must revert into proportional parts , and the difficulty remain the same . sect . ii. the impossibility of dividing a physical continuum into parts interminably subdivisible , being thus amply demonstrated ; and the sophistry of the most specious recesses , invented to assist the contrary opinion , clearly detected : the residue of this chapter belongs to our vindication of the same thesis from the guilt of those absurdities and in●ongruities , which the dissenting faction hath charged upon it . empiricus , with great virulency of language inveighing against the patrons of atoms , accuseth them of subverting all local motion , by supposing that not only place and time , but also natural quantity indivisible beyond insectile parts . to make this the more credible , he objects ( ) that if we assume a line , consisting of nine insectils , and imagine two insectile bodies to be moved , with equal velocity , from the opposite extremes thereof toward the middle ; it must be , to their mutual occurse , and convention in the middle , necessary that both possess the median part of the median , or fifth insectile place ( there being no cause , why one should possess it more then the other ) when yet both the places and bodies therein moved , are praesumed insectile , i. e. without parts . ( ) that all bodies must be moved with equal celerity ; for , the pace of the sun and that of a snail must be aequivelox , if both move through an insectile space , in an insectile time. ( ) that , if many concentrical circles be described by the circumduction of one rule , defixed upon one of its extremes , as upon a centre ; since they are all delineated at one and the same time , and some are greater then others : it must follow , that unequal portions of circles are described in the same individual point of time , and consequently that an insectile of an interior circle must be aequated to a sectile of an exterior . to these our modern anti-epicureans have superadded many other 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or inconcistencies , as dependent on the position of insectility viz. ( ) that a line of unaequal insectiles , suppose of . . . or . cannot be divided into two equal halfs : when yet , that any line whatever may be exactly bipartited , is demonstrable to sense . ( ) that a less line cannot be divided into so many parts , as a greater : though the contrary be concordant to the maximes of geometry . ( ) that though lines drawn betwixt all the points of the leggs of an isoscelis triangle , parallel to its base , are less then its base ; yet will they be found greater : because , supposing the base to be of five points , and the leggs of ; it must follow , that the least line , or the nearest to the vertex , doth consist of only two points , the second of , the third of , the fourth of , the fifth of , the sixth of , the seventh of , and the greatest , or nearest to the base , of ; then which nothing can be more absurd . ( ) that the diagone of a quadrate would be commensurable in longitude with the side thereof : one and the same point being the measure common to both ; though the contrary is demonstrated by euclid . ( ) that the same diagone of a quadrate could not be greater then , but exactly adaequate to the side thereof : because each of all its points must be possessed by just so many , nor more nor fewer lines , then may be drawn betwixt the points of the opposite sides ; which is highly absurd . ( ) that , with the danger of no less absurdity , would not a semicircle be greater then its diametre ; since to every point in the semicircle there would respond another in the diametre , and there would be in both as many points , on which as many perpendicular lines , deduced from them , might be incident . ( ) that , according to the supposition of insectility , of many concentrick circles the exterior would not be greater then the interior ; insomuch as all the lines drawn from all the points of it toward the centre , must pass through as many points of the other . many other exceptions lye against our insectility ; but being they are of the same nature with these , rather mathematical , then physical , and that one common solution will serve them all : we may not abuse our leasure in their recitation . that there have been hot and scarce ingenious altercations among the gravest and leading philosophers , in all ages ; and even about those arguments , which wear the proper characters of truth fairly engraven on their fronts : can be esteemed no wonder ; because the general custom of men to speculate the fabrick of nature through the deceivable glass of authority , doth amply solve it . but , that so many examples of sagacity and disquisition , as have condemned the hypothesis of atoms , should think their choler against the patrons of it excusable only by the allegation of these light and impertinent exceptions : cannot be denyed the reputation of a wonder , and such a one as no plea , but an ambitious affectation of extraordinary subtilty in the invention of sophisms ( wherein fallacy is so neatly disguised in the amiable habit of right reason , as to be charming enough to impose upon the incircumspection of common credulity , and cast disparagement upon the most noble and evident fundamentals . ) can palliate . for , certainly , they could not be ignorant , that they corrupted the state of the quaestion ; the minimum , or insectile of atomists , being not mathematicum , but physicum , and of a far different nature from that least of quantity , which geometricians imagining only , denominate a point . and therefore , what cicero ( . de finib . ) said against epicurus ; non esse ne illud quidem physici , credere aliquid esse minimum : may be justly converted into , esse praesertim physici , naturale quoddam minimum asserere ; since nature in her exolutions cannot progress to infinity . we say , physici ; because it is the naturalist , whose enquiries are confined to sensible objects , and such as are really existent in nature : nor is he at all concerned , to use those abstractions ( as they are termed ) from matter ; the mathematician being the only he , who cannot , with safety to his principles , admit the tenet of insectility , or term of divisibility . for to him only is it requisite , to suppose and speculate quantity abstract from corporiety ; it being evident , that if he did allow any magnitude divisible only into individuals , or that the number of possible parts , or points in a continuum , were definite : then could he not erect geometrical , or exquisite demonstrations . and hence only is it , that he supposeth an infinitude of points in every the least continuum , or ( in his own phrase ) that every continuum is div●sible into parts infinitely subdivisible : not that he doth , or can really understand it so ; but that many convenient conclusions , and no considerable incongruities , follow upon the concession thereof . this considered , we need no other evidence , that all the former objections , accumulated upon epicurus by the malitious sophistry of empiricus and others , concern only the mathematicians , not the physiologist , who is a stranger to their supposition of interminable divisibility . if this response praevail not , and that we must yet sustain this seeming dilemma ; either the suppositions of the mathematicians are true or false : if true , then doth their verity hold , when accommodated to physical theorems , by the assumption of any sensible continuum , or real magnitude ; if false , then are not the conclusions necessary , that are deduced from them , but the contray is apparent in their demonstrations ; therefore , &c. our expedient is , that , though we should concede those suppositions to be false , yet may they afford true and necessary conclusions : every novice in logick well knowing how to extract undeniable conclusions out of most false propositions , only supposed true , as may be instanced in this syllogism . omnes arbores sunt in coelo ( that 's false ) sed omnia sydera sunt arbores ( that 's false ) ergo , omnia sydera sunt in coelo ( that 's indisputable ) . besides , 't is evident , that of those many hypotheses celebrated by astronomers , either no one is absolutely true , or all except one , are false : yet experience assures , that from all , at least from most of them the motions of coelestial bodies may be described , and respective calculations instituted with equal certude . digression . here , because our reader cannot but perceive us occasionally fallen into the mouth of that eminent quaestion ; an liceat in materiam physicam , sive sensibilem , transferre geometricas demonstrationes ? whether it be convenient to transfer geometrical demonstrations to physical or sensible quantity ? since they , who accept the negative , seem to adnihilate the use of geometry : we need not deprecate his impatience , though we digress so long , as to praesent him the summary of our thoughts concerning it . first , we conceive it not justifiable , alwayes to expect the eviction of physical theorems ; by geometrical demonstrations . this may be authorized from hence , that geometricians themselves , when they fall upon the theory of those parts of the mathematicks , which are physicomathematical , or of a mi●t and complex consideration , are frequently necessitated to convert to suppositions , not only different from , but directly and openly repugnant to their own proper and establisht maxims . thus ▪ in opticks , euclid concedes a least angle ; and vitellio admits a least light , such as being once understood to be divided , hath no longer the act of light , i. e. wholly disappears : which is no less , then in opticks to allow a term , or point of consistence to the division of quantity , which yet in geometry they hold capable of an infinite process . we are provided of a most pertinent example , for the illustration of the whole matter . the geometrician demonstrateth the division of a line into two equal segments , to be a thing not only possible , but most easie : and yet cannot the physiologist be induced to swallow it , as really performable . for he considers ( ) that the superfice of no body can be so exactly smooth and polite , as to be devoyd of all uneveness or asperity , every common microscope discovering numerous inaequalities in the surface of even the best cut diamonds , and the finest chrystal , bodies , whose tralucency sufficiently confesseth them to be exceeding polite : and consequently , that there is assumable thereon no line so perfectly uniform , as not to be made unequal by many valleculae and monticulae , small pits and protuberances frequently interjacent . ( ) that the edge of no dissecting instrument can be so acute , as not to draw a line of some latitude . ( ) that should the edge of the acutest rasor be laid on the foot of a handworm , which may be effected by the advantage of a good magnifying glass , and a steady hand : yet is that composed of many myriads of atoms , or insensible particles of the first universal matter . and thence concludes that no real line drawn upon the superfice of any the smoothest body , can be practically divided into two halfs , so exactly , as that the section shall be in that part , which is truly the median to both extremes . since , that part , which appears , to the sense , to be the median , and is most exiguous ; doth yet consist of so many myriads of particles , as that though the edge of the rasor be imposed by many myriads of particles aside of that , which is truly in the middle , yet will it seem to the eye still to be one and the same . this duely perpended , we have no cause to fear the section of an atome , though the edge of a knife were imposed directly upon it : since the edge must be gross and blunt , if compared to the exility of an atome : so that we may allow it to divide an assembly , or heap of atoms , but never to cut a single one . secondly , we judge it expedient in some cases to accommodate suppositions geometrical to subjects merely physical ; but to this end only , that we may thereby acquire majorem 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , a greater degree of acuteness , or advance our speculations to more exactness . thus the soul of the mathematicks , archimed , ( de arenarum num . ) supposed the diametre of a grain of poppy seed to consist of particles ; not that he conceived that any art could really discern so vast a multitude of parts in a body of so minute circumscription : but that , by transferring the same reason to another body of larger dimensions , he might attain the certitude of his proposition by so much the nearer , by how much the less he might have erred by neglecting one of those many particles . thus also is it the custom of geometricians , in order to their exactness in calculations , to imagine the semi-diametre , or radius of any circle , divided into many myriads of parts ; not that so many parts can be really distinguished in any radius , but that , when comparation is made betwixt the radius , and other right lines , which in parts aliquotal , or such as are expressed by whole numbers , do not exactly respond thereunto , particles may be found out so exile , as though one , or the fraction of one of them be neglected yet can no sensible error ensue thereupon . and this ( in a word ) seems to be the true and only cause , why mathematicians constantly suppose every continuum to consist of infinite parts : not that they can , or ought to understand it to be really so ; but that they may conserve to themselves a liberty of insensible latitude , by subdividing each division of parts into so many as they please ; for , they well know , that the physiologist is in the right , when he admits no infinity , but only an innumerability of parts in natuaral continuum . lastly , if these reasons appear not weighty enough to counterpoise the contrary persuasion ; we can aggravate them with a grain of noble authority . for , no meaner a man then plato , who seems to have understood geometry as well as the aegyptian theuth , the supposed inventor thereof ( vide platon . in phaedro ) and to have honoured it much more in a solemn panegyrick ( . dialog . de rep. ) sharply reprehends eudoxus , archytas , menaechonus , &c. for their errour in endeavouring to adjust geometrical speculations to sensible objects : subnecting in positive termes , that ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) thereby the good of geometry was corrupted . ( lege marsil . ficin . in compend ▪ timaei . cap. . ) chap. iii. atoms , the first and vniversal matter . sect . i. no man so fit to receive and retain the impressions of truth , as he , who hath his virgin mind totally dispossessed of praejudice : and no thesis hath ever , since the envy of aristotle was so hot , as to burn the volumes of democritus and most of the elder philosophers , which might have conserved its lustre , been more eclipsed with a praesumption of sundry incongruities , then this noble one , that atoms are the first and catholique principle of bodies . requisite it is therefore that this chapter have , ianus like , two faces : one to look backward on those impediments to its general admission , the inconsistences charged upon , and sundry difficulties supposed inseparable from it ; the other to look forward at the plenary remonstrance of its verity . in obedience to this necessity , therefore , we advertise , first ; that it hath proved of no small disadvantage to the promotion of the doctrine of atoms , that the founders thereof have been accused of laying it down for a main fundamental , that there are two principles of all things in the universe , bodie and inanity ; importing the necessary concurrence of the inane space to the constitution of bodies complex , as well as of atoms . this absurdity hath been unworthily charged upon epicurus by plutarch , in these words ; principia esse epicuro infinitatem & inane : and upon leucippus and democritus by aristotle ( . metaphys . . ) in these ; plenum & inane elementa dicunt . to vindicate these mirrors of science from so dishonourable an imputation , we plead ; that though they held the universe to consist of two general parts , atoms and vacuity : yet did not they , therefore , affirm , that all things were composed of those two , as elementary principles . that which imposed upon their accusers judgment , was this , that supposing atoms and the inane space to be ingenite and incorruptible , they conceived the whole of nature to arise from them , as from its two universal parts ; but never dreamt so wild an alogy , as that all concretions , that are produced by generation , and subject to destruction by corruption , must derive their consistence from those two , in the capacity of elements , or componentia . for , albeit in some latitude and liberty of sense , they may be conceded elements , or principles of the universe : yet doth it not naturally follow , that therefore they must be equal principles , or elements of generables ; since atoms only fulfill that title , the inane space affording only place and discrimination . nor is it probable , that those , who had defined vacuity by incorporiety , should lapse into so manifest a contradiction , as to allow it to be any cause of corporiety , or to constitute one moiety of bodies . besides , neither can epicurus in any of those fragments of his , redeemed from the jaws of oblivion by laertius , cicero , empiricus , plutarch , &c. nor his faithful disciple and paraphrast , lucretius , in all his physiology , be found , to have affirmed the contexture of any concretion from inanity , but of all things simply and solely from atoms . and for democritus , him doth even aristotle himself wholly acquit of this error ; for ( in . phys. ) enumerating the several opinions of the ancients concerning the principles , or elements of all things , he saith of him ; fecit principiorum genus unicum , figuras verò differentes . all therefore that lyeth against them in this case , is only that they asserted the interspersion or dissemination of inanity among the incontingent particles of bodies concrete , as of absolute necessity to their peculiar contemperation : which we conceive our selves obliged to embrace and defend , untill it shall be proved unto us , by more then paralogistical arguments , that there is any one concretion in the world so perfectly solid , as to contain nothing of the inane space intermixt ▪ which till it can be demonstrated that a concretion may be so solid , as to be indissoluble , we have no cause to expect . secondly , that the patrons of atoms do not ( as the malice of some , and incogitancy of others hath praetended , to cast disparagement upon their theory ) deny the existence of those four elements admitted by most philosophers : but allow them to be elementa secundaria , elements elementated , i. e. consisting of atoms , as their first and highest principles . thus much we may certifie from that of lucretius ( . lib. ) treating of atoms ; unde mare , & terrae possent augescere , & unde adpareret spatium coeli * domus , altaque tecta , tolleret a terris procul , & consurgeret aer , &c. nor can the most subtle of their adversaries make this their tenet bear an action of trespass against right reason ; especially when their advocate shall urge , the great dissent of the ancients concerning both the number and original of elements , the insufficiency of any one element to the production of compound natures , and that the four vulgar elements cannot justly be honoured with the attributes of the first matter . ( ) the dissent of the ancients about the number of elements cannot be unknown to any , who hath revolved their monuments and taken a list of their several opinions ; their own , or their scholiasts volumes lying open to record , that of those who fixt upon the four vulgar elements , fire , aer , earth , water , for the universal principles , some constituted only one single first principle , from which by consideration and rarefaction , the other three did proceed , and from them all elementated concretions : among which are heraclitus , who selected fire ; anaximenes , who pitched upon aer ; thales milesius , who praeferred water ; and pherecydes , who was for earth . others supposed only two primary , from which likewise , by condensation and rarefaction the other two secondary were produced : as xenophanes would have earth and water ; parmenides contended for fire and earth ; oenopides chius for fire and aer ; and hippo rheginus for fire and water . others advanced one step higher , and there acquiesced in three ; as onomacritus and his proselytes affirmed fire , water , and earth . and some made out the quaternian , and superadded also aer ; the principal of which was empedocles . now , to him who remembers , that there can be but one truth ; and thereupon justly inferrs , that of many disagreeing opinions concerning one and the same subject , either all , or all except one must be false ; and that it is not easie which to prefer , when they are all made equally plausible by a parity of specious arguments : it cannot appear either a defect of judgment , or an affectation of singularity in democritus and epicurus to have suspected them all of incertitude , and founded their physiology on an hypothesis of one single principle , atoms , from the various transposition , configuration , motion , and quiescence of whose insensible particles , all the four generally admitted elements may be derived , and into which they may , at the term of exsolubility , revert without the least hazard of absurdity or impossibility ; as will fall to our ample enunciation in our subsequent enquiries into the originals of qualities , and the causes of generation and corruption . ( ) that one of the four elements cannot singly suffice to the production of any compound nature ; needs no other eviction but that argument of hippocrates ( de natur. hominis ) quo pacto , cùm unum existat , generabit aliquid , nisi cùm aliquo misceatur ? instance we in heraclitus proto-element , fire ; from which nothing but fire can be educed : though it run through all the degrees of those fertile modifications of densescence and rarescence ▪ ( ) to suppose rarefaction and condensation , without the more or less of inanity intercepted ; as they do : is to usurp the concession of an impossibility . ( ) t is absurd , to conceive fire transformable , by extinction , into any other element : because a simple substance cannot be subject to essential transmutation . so that , if after its extinction any thing of fire remain , as must till adnihilation be admitted ; its surviving part must be the common matter , such as atoms , which according to the various and respective addition , detraction , transposition , agitation , or quiet of them , now put on the form of fire , then of aer , anon of water , and lastly of earth ; since , in their original simplicity , they have no actual , but a potential determination to the forms of all , indiscriminately . and , what is here urged , to evince the impossibility of fires being the sole catholique element , carrieth the same proportion of reason and evidence , ( the two pathognomick characters of verity ) to subvert the supposition of any of the other three for the substantial principle of the rest . ( ) that though the four vulgar elements may be the father , yet can they not be the grandfather principle to all concretions ; is evidencible from hence . ( ) they are contrary each to other , and so not only asymbolical or disharmonious , but perfectly destructive among themselves , at least uncapable of that mutual correspondence requisite to peaceful and durable coalescence . ( ) they are praesumed to coalesce , and their concretions to consist without inanity interspersed among their incontiguous particles : which is impossible . ( ) their defendants themselves concede a degree of dissolution beyond them : and consequently that they know a principle senior . ( ) their patrons must grant either that they , by a praevious deperdition of their own nature , are changed into concretions , which by mutation of forms escheat again into elements ; in which case elements can be no more the principle of concretions , then concretions the principle of elements , since their generations must be vicissitudinary and circular , as that of water and ice : or , that , conserving their own natures immutable , they make only confused heaps , and confer only their visible bulks to all productions ; in which case , nothing can revera be said to be generated , since all generations owe their proprieties and peculiar denominations to their forms . ( ) whoso admits a reciprocal or symbolical transmutation of elements : must also admit one common , and so a former matter , which may successively invest it self in their several forms ; for contraries , while contraries , cannot unite in the assumption of the same nature . ( ) that achilles , or champian objection , that vegetables and animals owe their nutrition and increment to the four elements , is soon conquered by replying ; that elements are not therefore the first principles , but rather those from whose respective contexture they borrowed the nature of elements , and so derived an aptitude , or qualification requisite to the condition of aliment . thirdly , that the principles of democritus , epicurus , &c. are toto coelo , by irreconcileable disparities , different from those of anaxagoras , called 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , consimilar parts , or abstractly , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , similarity ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) because they are supposed to be parts in all points consimilar to the things generated of them , according to the paraphrase of plutarch ( . placit . . ) who there explains it by the example of aliment . wherein , whether it be wine , water , bread , flesh , fruits , &c. notwithstanding the seeming difference in the outward form , there are actually contained some sanguineous , some carnous , other osseous , other spermatick parts , which , upon their sequestration , and selection by the nutritive faculty are discretely apposed to the sanguineous , carnous , osseous , and spermatick parts praeexistent in the body nourisht . and the disparity doth chiefly consist herein ; that they endow their atoms with only three congenial qualities , viz. magnitude , figure , and gravity : but he investeth his similarities with as great variety of essential proprieties , as there is of qualities , nay idiosyncrasies in bodies . which to suppose , is to dote : ( ) because if the nature of the whole be one and the same with that of its parts : then must the principles , no less then the concretions consisting of them , be obnoxious to corruption . ( ) because , if it be assumed , that like are made of like , or that concretions are absolutely identical to their elements ; it cannot be denyed ; that there are la●ghing and weeping principles concurrent to the generations of laughing and weeping compositions . ( ) because from hence , that ( concordant to anaxagoras ) all things are actually existent in all things , and that the difference resteth only in the external apparence , arising from the praedominion of such or such over such or such parts of the consimilar principles : it necessarily ensues ( as aristotle argueth against him , physic. . ) that in the contusion , section , or detrition of fruits , herbs , &c. there must frequently appear blood , milk , sperm , &c. as being thereby enfranchised from the tyranny of those parts , which ruled the rost in the induction of the outward apparence , and emergent out of those clouds which concealed and disguised them . all which are absurdities so palpable that a blind man may thereby distinguish the rough and spurious hypothesis of anaxagoras , from the smooth and genuine principle of democritus and his sectators . fourthly and lastly , that the difficulties , which many dissenters , and more eminently their most potent and declared opponent , lactantius ( in lib. de ira d●● , cap. . ) have posted up against the supposition of atoms for the catholick principle of bodies concrete , thereby to praevent their further approbation , and admission into the schools ; carry not moments enough of reason to in●●ect and determine the judgment of an aequitable arbiter to a suspition , much less a positive negation of its verisimility . of this we desire our reader to be judge , when he hath made himself competent , by a patient hearing , and upright perpension of the pleas of both parties , here praesented . ( ) anti-atomist ; whence had these minute and indivisible bodies , called atoms , their original ? or , out of what were they educed ? atomist ; this inapposite demand lyeth open to a double response . as a mere philosopher i return ; that the assumption of atoms for the first matter doth expresly praevent the pertinency of this quaere . nor would aristotle , plato , or any other of the ethnick philosophers , who would not hear of a creation , or production of the first matter out of nothing , but contumaciously maintained its ingeneration and eternity , have had gravity enough to suppress the insurrection of their spleen against the absurdity thereof : since to enquire the matter of the first matter , is a contradiction in terminis . as a proficient in the sacred school of moses , i may answer ; that the fruitful fiat of god , out of the tohu , or infinite space of nothing , called up a sufficient stock of the first matter , for the fabrication of the world in that most excellent form , which he had idea'd in his own omniscient intellect from eternity . ( ) anti-atomist ; if atoms be smooth and sphaerical , as their inventors suppose ; it is impossible they should take mutual hold each of other , so as by reciprocal adhaesion and coalition to constitute any concretion . for , what power can mould an heap of millet-seed into a durable figure , when the laevitude or politeness , and roundness of the grains inexcusably interdict their coition into a mass ? atomist ; this objection discovers the rancour , no less then the praecedent interrogation did the weakness of the proposers . for , they could not be ignorant , that the defendants of atoms do not suppose them to be all smooth and globular , but of all sorts of figures requisite to mutual application , coalition , cohaerence . and therefore they could not but expect this solution . that , though polite and orbicular atoms , cannot by mutual apprehension and revinction each of other , compact themselves into a mass ; yet may they be apprehended and retained by the hooks , and accommodated to the creeks and angles of other atoms , of hamous and angular figures , and so conspire to the coagmentation of a mass , that needs no other caement besides the mutual dependence of its component particles , to maintain its tenacity and compingence . this may receive light , from observation of the successive separation of the dissimilar parts of bodies , by evaporation . for , first those atoms , which are more smooth , or less angular and hamous , easily extricate themselves , and disperse from the concreted mass ; and then , after many and various evolutions , circumgyrations , and change of positions , the more rough , hamous , and angular , they expede themselves from reciprocal concatenation , and at last , being wholly disbanded , pursue the inclination of their inhaerent motive faculty , and disappear . experience demonstrating , that by how much more unctuous and tenacious any consistence is , by so much a longer time do the particles thereof require to their exhalation . thus is water much sooner evaporated , then oyl : and lead then silver . ( ) anti-atomist ; if atoms be unequal in their superfice , and have angular and hamous processes ; then are they capable of having their rugosities planed by detrition , and their hooks and points taken off by amputation : contrary to their principle propriety , indivisibility . atomist ; the hooks , angles , asperities , and processes of atoms are as insecable and infrangible as the residue of their bodies , in respect an equal solidity belongs to them , by reason of their defect of inanity interspersed , the intermixture of inanity being the cause of all divisibility . haec , quae sunt rerum primordia , nulla potest vis stringere , nam solido vincunt ea corpore demum . ( ) anti-atomist ; that bodies of small circumscription , such as grains of sand , may be amassed from a syndrome , and coagmentation of atoms ; seems , indeed , to stand in some proportion to probability : but to conceive a possibility , that so vast a bulk , as the adspectable world bears may arise out of things but one degree above nothing , such insensible materials convened and conglobated ; is a symptome of such madness , as melancholy adust cannot excuse , and for which physitians are yet to study a cure . atomist ; to doubt the possibility , nay dispute the probability of it : is certainly the greater madness . for , since a small stone may be made up of a coagmentation of grains of sand ; a multitude of small stones , by coacervation , make up a rock ; many rocks by aggregation , make a mountain ; many mountains , by coaptation , make up the globe of earth ; since the sun , the heavens , nay the world may arise from the conjunction of parts of dimensions equal to the terrestrial globe : what impossibility doth he incurr , who conceives the universe to be amassed out of atoms ? doubtless , no bulk can be imagined of such immense dimensions , as that the greatest parts thereof may not be divided into less , and those again be subdivided into less ; so that , by a successive degradation down the scale of magnitude , we may not at last arrive at the foot thereof , which cannot be conceived other then atoms . should it appear unconceivable to any that a pismire may perform a perambulation round the terrestrial globe ; we advise him to institute this climax of dimensions , and consider , first that the ambite of the earth is defined by miles , that miles are commensurated by paces , paces consist of feet , feet of digits , digits of grains , &c. and then he may soon be convinced , that the step of a pismire holds no great disproportion to a grain , and that a grain holds a manifest proportion to a digit , a digit to a foot , a foot to a pace , a pace to a perch , a perch to a furlong , a furlong to a mile , and so to the circumference of the whole earth , yea by multiplication to the convexity of the whole world. if any expect a further illustration of this point , it can cost him no more but the pains of reading the . page of our treatise against atheism ; and of archimeds book de arenarum numero . ( ) anti-atomist ; if all peices of nature derived their origine from individual particles ; then would there be no need of seminalities to specifie each production , but every thing would arise indiscriminately from atoms , accidentally concurring and cohaering : so that vegetables might spring up , without the praeactivity of seeds , without the assistance of moysture , without the fructifying influence of the sun , without the nutrication of the earth ; and all animals be generated spontaneously , or without the prolification of distinct sexes . atomist ; this inference is ingenuine , because unnecessary , since all atoms are not consimilar , or of one sort , nor have they an equal aptitude to the conformation of all bodies . hence comes it , that of them are first composed certain moleculae , small masses , of various figures , which are the seminaries of various productions ; and then , from those determinate seminaries do all specifical generations receive their contexture and constitution , so praecisely , that they cannot owe their configuration to any others . and , therefore , since the earth , impraegnated with fertility , by the sacred magick of the creators benediction , contains the seeds of all vegetables ; they cannot arise but from the earth , nor subsist or augment without roots , by the mediation of which , other small consimilar masses of atoms are continually allected for their nutrition ▪ nor without moysture , by the benefit of which , those minute masses are diluted , and so adapted for transportation and final assimilation ; nor without the influence of the sun , by vertue whereof their vegetative faculty is conserved , cherished and promoted in its operations . which reason is aequivalent also to the generation , nutrition and increment of animals . ( ) anti-atomist ; if your proto-element , atoms , be the principle of our common elements , according to the various configurations of it into moleculae , or small masses ; and that those are the seminaries of all things : then may it be thence inferred , that the seeds of fire are invisibly contained in flints , nay more , in a sphaerical glass of water , exposed to the directly incident rayes of the sun ; our sense convincing , that fire is usually kindled either way . atomist ; allowing the legality of your illation , we affirm , that in a flint are concealed not only the atoms , but moleculae , or seeds of fire , which wanting only retection , or liberty of exsilition , to their apparence in the forme of fire , acquire it by excussion , and pursuing their own rapid motion undiquaque , discover themselves both by affecting the sight and accension of any easily combustible matter ▪ on which they shall pitch , and into whose pores they shall with exceeding celerity penetrate . nor can any man solve this eminent phaenomenon so well , as by conceiving ; that the body of a flint , being composed of many igneous ( i. e. most exile , sphaerical , and agile ) atoms , wedged in among others of different dimensions and figures ; ( which contexture is the cause of its hardness , rigidity and friability ) upon percussion by some other body conveniently hard , the insensible particles thereof suffering extraordinary stress and violence , in regard it hath but little and few vacuola , or empty spaces intermixt , and so wanting room to recede and disperse , are conglomorated and agitated among themselves with such impetuositie , as determinately causeth the constitution of fire . it being manifest , that violent motion generateth heat : and confessed even by aristotle ( . meteor . . ) that fire is nothing but the hyperbole or last degree of heat . secondly , that the seeds of fire are not contained either in the sphaerical glass or the the water included therein ; but in the beams of the sun ( whose composition is altogether of igneous atoms ) which being deradiated in dispersed lines , want only concurse and coition to their investment in the visible form of fire ; and that the figure of the glass naturally induceth , it being the nature of either a convex , or concave glass to transmit many beams variously incident towards one and the same point , which the virtue of union advanceth to the force of ignition . having thus vindicated our atoms from the supposed competition of the inane space , in the dignity of being one principle of bodies ; reconciled them ●o the peripatetick elements ; discriminated them from the consimilar particles of anaxagoras ; solved the most considerable of the difficulties charged upon them ; and thereby fully performed our assumption of removing the principal praetexts of prajudice : we may now , with more both of perspicuity , and hopes of perswasion , advance to the demonstration of our thesis , the title and argument of this chapter . sect . ii. besides the manifest allusion of reason , we have the assent of all philosophers , who have declared their opinions concerning the composition of a continuum , to assure a necessity , that it must consist either ( ) of mathematical points ; or ( ) of parts and mathematical points , united ; or ( ) of a simple entity , before actual division , indistinct ; or ( ) of individuals , i. e. atoms . ( ) not of mathematical points ; because 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , punctum , in the sense of euclid , is cujus nulla sit pars , in respect it wants all dimensions , and consequently all figure : which is the ground of aristotles axiom , punctum puncto additum non potest facere majus . to render the absurdity of this opinion yet more conspicuous , let us remember , that the authors and defendants of it have divided themselves into three distinct factions . ( ) some have admitted in a continuum , points finite simpliciter & determinatè ; ( ) others allow points also finite , but not simpliciter , sed 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 secundum quid ; ( ) and others contend for points infinite , simpliciter ▪ & absolutè . the first and second endeavour to stagger the former axiom of aristotle , by an illegal transition from quantity continued , to discrete , alledging this instance , that one unity added to another makes a greater quantity . the last recur to plato's authority , who concedeth two infinites , ● greater and less , commemorated by aristotle ( . phys . . ) now , for a joint redargution of all , we demand , how they can divide a line consisting of insectiles into two equal segments ? for , either they must cast off the intermediate insectile , or annex it to one division : if the first , they split themselves upon that rock , our supposition ; if the last , they clash with the . proposit . . lib. euclid . to evade the force of this dilemma , they have invented many subter●uges : but how unsuccessfully , may be enquired of aristotle ( in . physicor . ) who there convicts them all of either falsity , or impossibility ; where , having praemised an excellent enunciation of the analogy between motion , time , and place , he apodictically concludes , that , if a continuum did consist of points mathematical , all motions would be equally swift . notwithstanding this , such was the contumacy of arriaga , that in hopes to elude this insoluble difficulty , he praetends to discover a new kind of motion , distinguished by certain respites , or pauses intercedent● thereupon inferring that all things are moved , during their motion , with equal celerity , but because the motion of one thing is intercepted with many pauses , and the motion of another with few , therefore doth the motion of this seem swift , and the motion of that slow ; as if the degrees of celerity and tardity did respond to the frequency and rarity of respites interceding . if this be true , then must a pismire move flower then an eagle only because this dist●nguisheth its motion by shorter pauses , and that by longer : nor can a faulcon overtake a partridge , since our eyes assure , that a p●rtridge strike● six strooks at least with his wings ▪ while its 〈◊〉 strikes one . mar●gravius ( in histor . animal . brasilicus ) tells of an animal , which from the wonderful ta●●igradous incession of it , is named by the portugals priguiza , or lubart : because though goaded on , it cannot snail over a stage of paces in hours . had arriaga beheld this sloth , either he must have disavowed his nicety , or held it an equal lay which should have sooner run over a four mile course , that , or the fleetest courser in the hippodrome at alexandria : because the pauses , which intercept the constant progression of the one , in the space of paces , cannot be more then those that interrupt the continuity of the others motion , in the space of four miles . these considerations therefore enable us to conclude , that those who constitute a continuum of points mathematical , absurdly maintain , ( ) that a point added to a point makes an augmentation of quantity ; ( ) that no motion is successive , but only discrete ; ( ) that all motions are of equal velocity , sunt enim puncta minimum quod pertransiri possint : and arriaga's quiet , imagined to be in motions , is no part of motion . ( ) that a wheel is dissolved , when circumrotated upon its axis ; for , since the exterior circle must praecede the interior , at least , by one point , it follows that the same points do not correspond to the same points ; which is absurd and incredible . therefore is not a continuum composed of mathematical points . ( ) not of parts and mathematical points , united . because ( ) parts cannot be conceived to be united or terminated , unless by an adaequation of points to them ; ( ) since those points , which are imagined to concur to the conjunction of parts , are even by suarez the chief patron of them , ( in metaphys . disput. de quantitat . ) named entia modalia ; it must thence follow , that parts , which are entia absoluta , cannot consist without them ; which is ridicul●●s . ( ) since they allow no last part , how can there be a last , i. e. a terminative point ? ( ) either something , or nothing is intermediate between one indivisible and other indivisibles : if something , then will there be a part without points ; if nothing , then must the whole consist of indivisibles , which is the point at which we aim . ( ) not of a simple entity before division , indistinct ; as not a few of our modern metaphysicians have dreamt , among whom albertinus was a grand master . who , that he might palliate the difficulty of the distinction of par● , that threatned an easie subversion of his phantastick position ; would needs have that all distinction doth depend ab extrinseco , i. e. ariseth only from mental designation , or actual division . but , o the vanity of affected subtilty ! all that he , or his whole faction hath erected upon this foundation of sand , may be blown down with one blast of this single argument . those things which can exist being actually separate ; are really distin●t : but parts can exist being actually separate ; therefore are they really distinct , even before division . for division doth not give them their peculiar entity and individuation , which is essential to them and the root of distinction . the major is the general and only rule of distinctions , which who●● denyes cannot distinguish plato from aristotle , nor albertinus from thersites . the minor holds its verity of sense , for the part a , is existent without the part b , though being before conjoyned , they both conspired to the constitution of one continuum . and that the propriety of entity , is the base of distinguibility , is verified by that serene axiome , per idem res dis●inguitur ab omni alta , per quod constituitur in suo esse . therefore cannot a continuum consist of a simple entity before division indistinct : but of individuals , or atoms , which is our scope and conclusion . our second argument flowes from the nature of union . for the decent introduction of which , we are to recognize , that a modal ens cannot subsist without conjunction to an absolute ; as , to exemplifie , intellection cannot be without the intellect , though on the reverse , the intellect may be without the act of intellection : so likewise cannot union be conceived without parts , though on the contrary , parts may be without union . and hence we thus argue : that only which is made independent●r à subjecto , or holds its essence ex proprio , is the term of creation ; but union is not independent à subjecto : therefore is not union the term of creation . since therefore the term of creation in the first matter is devoid of union ; it must consist of individuals , for division proceeds from the solution of union . this derives confirmation from hence ; that the subject from whence another is deduced , must be praecedent in nature to that which is derived : now the parts of the first matter are the subject from whence union is derived ; ergo , are the parts of the first matter in nature praecedent to all union ; and consequently they are individuals , i. e. atoms . if it be objected , that the understanding cannot apprehend the first matter to consist without some implicite union we appeal to that canon , quod non est de essentia rei , non ingreditur ejus conceptum : for , union not being of the essence of the parts of the first matter , ought not to fall under the comprisal of that idea , by which we speculate them . and , upon consequence , if they are conceived without implicite union : certainly they are conceived as individuals , or atoms . the major is justified by that common principle ; ex ●o quod res est , vel non est , dici potest vel esse , vel non esse ; conceptus enim mensura est rei entitas , mensura autem vocis est conceptus . and the certitude of the minor results from that metaphysical canon , nullus modus actualis est de essentia rei . upon these two arguments might we have accumulated sundry others of the like importance , such as are chiefly insisted upon by the modern redeemers of democritus and his noble principles from that obscurity and contempt , which the envy of time and the peripatetick had introduced , sennertus ( in hyponemat . de atomis . ) and magnenus ( in cap. . disput . . de atomis . ) and , in imitation of their ample model , have explicated the mystery of our thesis , from the syncritical and diacritical experiments of chymistry , ( whereby all bodies are sensibly dissolved into those moleculae , or first conventions of atoms , which carry their specifical seminaries ; and the heterogeneous parts of diverse concretions , after dissolution , coagmentated into one mass , and united per minimas ) but most eminently from that natural miracle , the tree of hermes , made by an artificial resuscitation of an entire herb from the atoms of it in a glass , honestly effected by a polonian physitian in the praesence of gaffarel , as himself records ( in curiositat . inaudit . ) asserted by quercetan ( in defens contra anonym . cap. ) and to the life described by hierem. cornarius , famous for his long profession of philosophy and medicine at brandenburgh , in an epistle to the great libavius , which he therefore made an appendix to his acute dissertation de resuscitatione formarum ex cineribus plantarum ( syntagm . arcan . chymic . lib. . cap. . ) but having upon an upright and mature perpension of their weight , found it such , as warrants our adscription of them to the golden number of those reasons , that are 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ( as aristotle speaks of other arguments concerning the same subject , in de generat . & corrupt . cap. . ) such as urge and compel the mind to an assent , and bid defiance to all solution : we judged our praesent fundamental sufficiently firm , though erected upon no other but those two pillars ; especially when we remembred that supererogation is a kind of deficiency . chap. iv. the essential proprieties of atoms . sect . i. that our theory of those qualities , which being congenial to , and inseparable from atoms , fulfil the necessary attributes of the first universal matter , may , according to the method requisite to perspicuity , immediately succeed to our demonstration of their existence , and the impossible elementation of concrete substances from any other general principles ; and that the expectance raised in our reader by our frequent transitory mention of the proprieties of atoms ; may be opportunely sated by a profess enumeration and enunciation thereof : are the two reasons that justifie our subnection of this to our praecedent discourse . the proprieties of our atoms difference themselves into general and specifical . the general are ( ) consimilarity of substance ; for all atoms being equally corporeal and solid , must be substantially identical , or of one and the same nature , knowing no disparity of essence . thus much aristotle intimates ( . physic. . ) when he infers democritus holding , esse principiorum 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , genus unicum , or 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , naturam ●nam , that the principles of all things are of one kind , or of one nature . in respect of this , there is no difference among atoms . ( ) magnitude , or quantity , which they cannot want , since they are not mathematical insectiles , but material realities , and quantity or extension is the proper and inseparable affection of matter ; and therefore every thing hath so much of extension , as it hath of matter . ( ) figure , which is the essential adjunct of their quantity . for , insomuch as atoms are most minute bodies , and stand diametrally opposed to points imaginary ; therefore must they have dimensions real , and consequently a termination of those dimensions in their extreme or superfice , i. e. determinate figure . which is the ground of magnenus . postulate ( de atomis , disput . . ) quicquid magnitudinem habet , finitamque extensionem , si pluribus dimensionibus substet , concedatur illi suam inesse figuram ; and perhaps also of euclids definition of figure , figura est , quae sub aliquo , vel sub aliquibus terminis comprehenditur . nor have they only a plain figure , but a solid one , according to that of euclid ( lib. . def . . ) solidum est , quod longitudinem , latitudinem , & crassitudinem habet . ( ) gravity , or weight ; which is also coessential to them in respect to their solidity , and the principle of their motion . and therefore epicurus had very good cause to add his 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , to democritus 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : which plutarch ( . placit . . ) expresly renders thus ; 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quia necesse est corpora moveri ipso impetu gravitatis . for , having supposed that motion was essentially competent to atoms , it must have been no venial defect , not to have assigned them a certain special faculty , or virtue for a cause to that motion praesumed ; and such must be their inhaerent gravity , or the tendency of weight . now , in respect to either of these three last proprieties , atoms may be conceived to admit of difference among themselves ; for , in regard of magnitude , some may be greater then others , of figure , some may be sphaerical , others cubical , some smooth , others rough , &c. and of gravity , some may be more , and others less ponderous , though this can cause no degrees of velocity or tardity in their motion , it being formerly demonstrated , that two bodies of different weights are aequally swift in their descent . to these essential attributes of atoms , empiricus hath superadded a fifth , viz. 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , renitency , or resistence . but , by his good leave , we cannot understand this to be any distinct propriety ; but as 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , something resilient from and dependent on their solidity , which is the formal reason of resistence : besides , we may confound their renitency with their gravity , insomuch as we commonly measure the gravity of any thing , by the renitency of it to our arms in the act of elevation . which may be the reason , why aphrodisaeus ( lib. . quest. cap. . ) enumerating the proprieties of atoms , takes no notice at all of their gravity ; but blends it under the most sensible effect thereof , resistence . the specifical are such as belong to atoms of particular sorts of figure , as smoothness , acuteness , angularity , and their contraries , asperity , obtuseness , orbicularity , &c. these , in the dialect of epicurus , are 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , cognatae proprietates . now all these proprieties , both generical , and specifical , or originary and dependent , are truly 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , as plutarch ( . adv . colot . ) calls them , congenial , and inseparable . other proprieties there are adscriptive to atoms , such as their concurse , connexion , position , order , number , &c. from which the qualities of compound bodies do emerge ; but since they are only communia accidentia , common accidents , or ( as lucretius ) atomorum eventa , the fortuitous events of atoms considered as complex and coadunated in the generation of concretions , and not in the intire simplicity of their essence ; and consequently seperable from them : therefore may we hope , that our reader will content himself with our bare mention of them in this place , which is designed for the more advantagious consideration of only the essential and inseparable . sect . ii. concerning the magnitude of atoms . magnitude and atoms , though two terms that make a graceful consonance to ears acquainted with the most charming harmony of reason , may yet sound harsh and discordant in those of the vulgar , which is accustomed to accept magnitude only comparatively , or as it stands antithetical to parvity : and therefore it concerns us to provide against misapprehension by an early advertisement ; that in our assumption of magnitude as the first essential propriety of atoms , we intend not that they hold any sensible bulk , but that , contrary to insectiles , or points mathematical , they are entities quantitive simply , i. e. realities endowed with certain corporeal dimensions , though most minute , and consisting in the lowest degree of physical quantity ; so that even those of the largest size , or rate , are much below the perception and discernment of the acutest opticks , and remain commensurable only by the finer digits of rational conjecture . and somewhat the more requisite may this praemonition seem , in respect that no meaner an author then theodoret hath , through gross inadvertency , stumbled at the same block of ambiguity . for ( in serm. . therap●ut . ) he positively affirms , that democritus , metrodorus , and epicurus , by their exile principles , atoms , meant no other but those small pulverized fragments of bodies , which the beams of the sun , transmitted through lattice windows , or chincks , make visible in the aer : when according to their genuine sense , one of those dusty granules , nay , the smallest of all things discernable by the eyes of linceus , though advantaged by the most exquisite engyscope , doth consist of myriads of myriads of thousands of true atoms , which are yet corporeal and possess a determinate extension . to avert the wonder impendent on this nice assertion , and tune our thoughts to a key high enough to attain the verisimility thereof ; we are first to let them down to a worthy acknowledgment of the exceeding grossnesse and dulnesse of our senses , when compared to the superlative subtility , and acuteness of nature in most of her operations : for that once done , we shall no longer boast the perspicacity of our opticks , nor circumscribe our intellectuals with the narrow line of our sensible discoveries , but learn there to set on our reason to hunt , where our sense is at a loss . doubtless , the slender crany of a pismire contains more distinct cellules , then that magnificent fabrick , the eschurial , doth rooms ; which though imperceptible to the eye of the body , are yet obvious to that of the mind : since no man can imagine how , otherwise , the faculties of sense and voluntary motion can be maintained , a perpetuall supply of animal ( or , a● d● . h●rv●● will have them , vital ) spirits being indispensably necessary to the continuation of those actions ; and therefore there must be elaboratories for the praeparation and confection , treasuries for the conservation , and various conduits for the emission , and occasional transvection of them into the nerves and muscles of that industrious and provident animal . the due resentment of which praegnant instance , is alone sufficient to demonstrate the incomputable degrees of distance betwixt the sensible capacity of man , and the curious mechanicks of nature : and make the acutest of us all call for a table-book to enroll this aphorism ; ubi humana industria subtilitasque desinit , inde incipit industria subtilitasque naturae . the wings of our arrogance being thus clipt , let us display those of our discoursive faculty , and try how near we can come to deprehend the magnitude , i. e. the parvity of atoms , by an ingenious conjecture . consider we , first , that an exquisite artist will make the movement of a watch , indicating the minute of the hour , the hour of the day , the day of the week , moneth , year , together with the age of the moon , and time of the seas reciprocation ; and all this in so small a compass , as to be decently worn in the pall of a ring : while a bungling smith can hardly bring down the model of his grosser wheels and balance so low , as freely to perform their motions in the hollow of a tower. if so ; well may we allow the finer fingers of that grand exemplar to all artificers , nature , to distinguish a greater multiplicity of parts in one grain of millet seed , then ruder man can in that great mountain , caucasus ; nay , in the whole terrestrial globe . consider we , with magnenus , that one grain of frankinsense being fired , doth so largely diffuse it self in fume , as to fill a space in the aer , more then seven hundred millions of times greater then it possessed before combustion . for , to the utmost dispersion of its fume , the space might easily have received of grains of frankinsense , equal in dimensions to the seed of a lupine , according to its altitude according to its latitude in the longitude in the superfice of the whole figure in the superfice of the end only in the area , or whole enclosure since , therefore , our nostrils ascertation , that in all that space of aer , there is no one particle which is not impraegnated with the fragrant exhalations of that combust grain of frankinsense , which , while it was entire might be by a steddy hand , a sharp incision knife , and a good magnifying glass , or by that shorter way of trituration , divided at least into a thousand sensible particles : it must follow , in spite of contradiction , that the sensible odorous particles of it do fulfil the number of . and , insomuch as each of these sensible particles , is mixt , it being lawful and commendable according to the subtile speculations of archimed ( in arenar . ) to assume that the smallest of them is composed of a million of elemental atoms : therefore by the same rule , must there have been in the whole grain of elemental atoms , at least . if so ; we have but one step lower to insectility , and so may guess at the exiguity of a single atome . consider we the delicate contexture of atoms , in the body of that smallest of animals , a handworm . first , if we speculate the outside of that organical tenement of life , a good engyscope will praesent our eye with not only an oval-head , and therein a mouth , or prominent snout , armed with an appendent proboscis , or trunk consisting of many villous filaments contorted into a cone , wherewith it perforates the skin , and sucks up the bloud of our hands ; but also many thighs , leggs , feet , toes , laterally ranged on each side ; many hairy tufts on the tail , and many asperities , protuberances , and rugosities in the skin . then our reason if we contemplate the inside thereof , will discover a great variety of organs necessary to the several functions of an animal . for nutrition , there must be gullet , stomach , intestines , liver , heart , veins ; or at least parts in their offices and uses perfectly analogous thereto : for vitality , there must be lungs , and heart for the praeparation and confection , and arteries for the general diffusion of spirits ; for locomotion voluntary and sensation , there must be brain , spinal marrow , nerves , tendons , muscles , ligaments , articulations ; and for the support and firmitude of all these , there must be some more solid stamina , or a kind of bones and cartilagineous contextures ; in a word , there must be all members requisite to entitle it to animation , with a double skin for the investiment of the whole machine . now , if we attentively compute , how many particles go to the composure of each of those organical parts , and how many myriads of atoms go to the contexture of each of those particles ( for even the spirits inservient to the motion of one of its toes , are compositions consisting of many thousands of atoms ) , as we shall think it no wonder , that the exile and industrious fingers of nature have distinguished , sequestred , selected , convened , accommodated , coadunated , and with as much aptitude as decorum disposed such an incomprehensible multitude of parts , in the structure of so minute an animal ; so may we , in some latitude of analogy , conjecture the extreme parvity of her common material , atoms . on this ingenious pin hung the thoughts of pliny , when ( in lib. . cap. & . ) he exclaimed , nusquam alibi naturae artificium spectabilius est , qu●m in insectis : in magnis siquidem corporibus , aut cer●è majoribus , facilis officina sequaci materia fuit . in his verò tam parvis , atque tam nullis ; que ratio , aut quanta vis , tanquam inextricabilis perfectio ? ubi tot sensus collocavit in culice ? & sunt alia dictu minora . sed ubi visum in ea praetendit ? ubi gustatum applicavit ? ubi odoratum inseruit ? ubi truculentam illam , & proportione maximam vocem ingeneravit ? qua subtilitate pennas adnexuit , praelongavit pedum crura , disposuit jejunam caveam , uti alvum , avidam sanguinis , & potissimum humani sitim accendit ? telum verò perfodiendo tergori , quo spiculavit ingenio ? atque cùm prae exilitate pene non videatur ita reciproca generavit arte , ut fodiendo acuminatum , pariter sorbendoque fistulosum esset , &c. here had we haulted a while , and wondered , how pliny could , without the assistance of a magnifying glass ( an invention , whose antiquity will hardly rise above the last revolution of saturn ) deprehend so vast a multiplicity of parts in the machine of an insect , of so small circumscription , that to commensurate the base of the visive cone , by which its slender image is transmitted to the pupil of the eye , would trouble a good master in opticks , and drive him to the minimus angulus of euclid : but that it soon came into our thoughts , that he speculated the same by the subtiler dioptrick of reason ; which indeed is the best engyscope of the mind , and renders many things perspicuous to the understanding , whose exceeding exility is their sufficient darkness . to put more weights into the scale of conjecture , let us moreover observe ; how great a quantity of water may be tinged with one grain of vermillion ; how many sheets of paper may be crimsoned with that tincture ; how innumerable are the points , by the apex of a needle , designable on each of those sheets : and when 't is manifest that many particles of vermillion are found in each of those points ; who can longer doubt , that the particles comprehended in the compass of that grain are indefinable by the exactest arithmetique . again , ( for we could be content , to let the almund tree bud , before we take off our cogitations from this pleasant argument ) consider we , how small a portion of oyl is consumed by the flame of a lamp , in a quarter of an hour ; and yet there is no moment passeth , wherein the stock of flame is not wasted and as fast repaired , which if it could be conserved alive all at once , would fill not only whole rooms , but even ample cities : and if so , what need we any further eviction of the extreme exiguity of those parts , of which all concretions are material'd ? had the ancients , indeed , been scrupulous in this point ; their want of that useful organ , the engyscope , might in some part have excused their incredulity : but for us , who enjoy the advantages thereof , and may , as often as the sun shines out , behold the most laevigated granule of dissolved pearl , therein praesented in the dimensions of a cherry stone , together with its various faces , planes , asperities , and angles , ( such as before inspection we did not imagine ) most clear and distinct , longer to dispute the possible parvity of component principles , is a gross disparagement to the certitude of sense , when it is exalted above deception , and all possible impediments to its sincere judicature are praevented . conclude we therefore , since the diametre of a granule of dust , when speculated through a good engyscope , is almost centuple to the diametre of the same , when lookt on meerly by the eye , on a sheet of venice paper : we may safely affirm , with archimed ( in arenario . ) that it is conflated of ten hundred thousand millions of insensible particles ; which is enough to verifie our praesent assumption . sect . iii. concerning the figures of atoms . in all the sufficiently prolix discourses of the ancient assertors of atoms , concerning their figure , and the no sparing commentaries of the moderns thereupon ; whatever seems either worthy our serious animadversions , or in anywise pertinent to our designation : may be , without perversion , or amission of importance , well comprized under one of these canons . ( ) that atoms are , in their simple essence , variously figurate ; ( ) that the distinct species of their figures are indefinite , or incomprehensible , though not simply , or absolutely infinite ; ( ) that the number of atoms retaining unto , or comprehended under each peculiar species of figure , is not only indefinite , but simply infinite . concerning the first ; we advertise , that no man is to conceive them to have supposed the figure of atoms deprehensible by the sight , or touch , no more then their magnitude , the termination whereof doth essence their figure , according to that definition of euclid , lately alledged ; but such , as being inferrible from manifold reasons , is obvious to the perception of the mind . which plutarch ( . placit . . ) personating epicurus , expresly declares in his , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , atomos proprias habere , sed ratione , seu mente contemplabiles figuras . to avouch the verity hereof , we need no other argument but this ; insomuch as every atome hath some determinate quantity , or extension , and that all quantity must be terminated in some certain figure : therefore is it necessary , that however exile the dimensions of an atome are , yet must the superfice thereof be or plane , or sphaerical , or angular , or cubical , &c. i. e. of some figure either regular , or irregular . to guard this assertion of the variety of figures in atoms , with other arguments of its verisimility ; let us consider , that all individuals , as well animate , as inanimate , are distinguishable each from other of the same species , by some peculiar signature of disparity visible in the superficial parts of their bodies : and reason will thereupon whisper us in the ear , that they are also different in their configurations ; and that the cause of that sensible dissimilitude , must be a peculiar , or idiosyncritical contexture of their insensible component particles . for animals , we may instance in the noblest species . among the myriads of swarms of men , who can find any two persons , so absolute twinns in the aer of their faces , the lines of their hands , the stature of their bodies , proportion of their members , &c. as that nature hath left no impression , whereby not only their familiar friends , but even strangers comparing them together , may distinguish one from the other ? for inanimates ; doth it not deserve our admiration , that in a whole bushel of corn , no two grains can be found so exquisitely respondent in similitude , as that a curious eye shall not discover some disparity betwixt them : and yet we appeal to strict observation , for the verity thereof . if our leasure and patience will bear it , let us conferr many leaves , collected at one time from the same tree ; and try whether among them all we can meet with any two perfectly consimilar in magnitude , colour , superfice , divarications of filaments , equality of stemms , and other external proportions . if not ; we must assent to a variety of configurations in their parts , and consequently admit no less , but indeed a farr greater variety of figures in the particles of those parts , their atoms . to these it concerns us to annex one singular experiment , easie , delightful , and satisfactory . exposing a vessel of salt water , to the sun , or other convenient heat , so as the aqueous parts thereof may be gently evaporated ; we may observe all the salt therein contained , to reside in the bottome , conformed into cubical masses . and , if we do the like with alum water , the alum will concrete in octohedrical figures . nay , the cubes generated of salt , will be so much the larger , by how much the more and deeper the water , wherein it was dissolved ; and è contra , so much the smaller , by how much shallower the water : so that from a large vessel will arise saline cubes in dimensions equal to those of a gamesters die ; but from a small we shall receive cubes , by five parts of six , lesser , and if we drop a small quantity of brine upon a plane piece of glass , the cubical concretions thereon fixing , will be so minute , as to require the help of an engyscope to their discernment . now , as to that part of this experiment , which more directly points at our praesent scope ; we may perceive the greater cubes to be a meer congeries or assembly of small ones , and those small ones to be coagmentated of others yet smaller , or certainly composed of exiguous masses bearing the figure of isoscele triangles , from four of which convened and mutually accommodated , every cube doth result . hence is it obvious to conjecture , that those small cubes , discernable only by an engyscope , are contexed of other smaller , and those again of smaller , until by a successive degradation they arrive at the exility of atoms , at least of those moleculae , which are the seminaries of salt , and , according to evident probability , of either exactly quadrate , or isoscele triangular figures . now , insomuch as the same , allowing the difference of figure , is conjectural also concerning alum , sugar , nitre , vitriol , &c. saline concretions : why may we not extend it also to all other compositions , especially such as have their configurations certain and determinate , according to their specifical nature . again , whoso substracts a diversity of figures from atoms : doth implicitely destroy the variety of sensibles . for , what doth cause the odoratory nerves of man to discriminate a rose from wormwood ? but the different configurations of those moleculae , flores elementorum , or seminaries of qualities , which being conflated of exceeding fine and small congregations of atoms , do constitute the odorable species ; and so make different impressions upon them . what makes a dog , by the meer sagacity of his nose , find out his master , in the dark , in a whole host of men ? but this ; that those subtle effluvia , or expirations , emitted insensibly from the body of his master , are of a different contexture from those of all others , and so make a different impression upon the mamillary processes , or smelling nerves of the dog. the like may also , with equal reason , be demanded concerning those wayes of discrimination , whereby all animals agnize their own from others young ; and beasts of prey , in their difficult venations , single out the embossed and chased , though blended together with numerous herds of the same species . nor doth the verisimility hereof hold only in objects of the sight and smelling ; but diffuseth to those of the hearing , tasting , and touching : as may be soon inferred by him , who shall do us the right , and himself the pleasure to descend to particulars . these things jointly considered , we are yet to seek , what may interdict our conception of great diversity of figures in the principles of concretions , atoms . concerning the second , viz. 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , esse figuras atomorum incomprehensibiles , non infinitas , that the figures of atoms are so various , as to be incomprehensible , though not simply infinite : this can be nor problem , nor paradox . for , though the species of regular figures be many , of irregular more , and of those that are producible from both regular and irregular , according to all the possible wayes of their commixture and transposition , so amusingly various ; as that the mind of man , though acquainted with all the mysteries of arithmetique and algebra , cannot attain to a definite compute , nor praecise d●●●ription of them all : yet do they not run up to absolute infinity , so as that there can be no extreme and terminating species . that the variety of figures competent to atoms , ought to be held only incomprehensible ; these reasons evince ( ) since atoms are circumscribed and limitate in magnitude , that configurations in diversity infinite should arise from that finite magnitude , is clearly impossible . for , every distinct figuration praesupposeth a distinct position of parts ; and the parts of finite magnitude may be transposed so many several wayes , as no further way of transposition can remain possible : otherwise there would be new and new parts inexhaustibly , and so magnitude would become infinite . ( ) if the diversity of figures were infinite , then could not the qualities arising to concretions from the various contexture of their parts , be certain and determinate : since , allowing an inexhaustible novelty of configurations , their insensible particles might be so variegated , as that a better then the best , and a worse then the worst 〈◊〉 configurations might be produced ; which is no obscure absurdity . ( ) all things are determined by contrary qualities , which are so extreme , that they admit many mediate or inclusive degrees , but none exclusive , or without their boundaries . ( ) that only a finite variety is sufficient to that incomprehensible diversity of figures , observed in nature . that the variety of figures allowable to atoms , is incomprehensible ; may be thus familiarized . thinke we , what great multiplicity of words may be composed of only a few letters variously transposed . for , if we assume only two letters , of them we can create only two words ; if three , ; if four , ; if five , ▪ if six , ; if seven , ; if eight , ; if nine , ▪ if ten , : so that before we fulfil the letters , the number of words componible of them , according to all the possible ways of positions , will swell above our computation . this done , let us no more but exchange letters for figures , and assuming only round , oblong , oval , eliptick , lenticular , plane , gibbous , turbinate , hamous , polite , hispid , conical , obtuse , tetrahedical , pentahedrical , hexahedrical , heptahedrical , dodecahedrical , icosahedrical , striate or skrewed , triangular , cylindrical atoms : cast up to what an inassignable number the figures producible from them , according to the several wayes of their composition and transposition , may amount . doubtless , we shall discover so great variety , as to elude our comprehension . if so , how much more incomprehensible must that diversity be , which is possible from the assumption , and complication of all the regular and irregular figures , that a good geometrician can conceive , and which it is justifiable for us to allow existent in nature ? but as for the last ; viz. that the number of atoms , retaining to each distinct species of figures , ariseth to infinity , i. e. that there are infinite oval , infinite pyramidal , infinite sphaerical , &c. atoms : from this we must declare our dissent . because , how great a number soever be assigned to atoms , yet must the same be defined by the capacity of the world , i. e. of the universe , as hath been formerly intimated . and , therefore , the common objection , that if so , the summe of things existent in the world , would be finite ; is what we most willingly admit , there being no necessity of their infinity , and a copious syndrome of reasons , that press the contrary . and as it is unnecessary to nature : so likewise to her commentator , the physiologist ; to whom it sufficeth , having exploded this delirium of infinity , to suppose ( ) that the material principles of the universe are essentially figurate , ( ) that the species of their figures are incomprehensible , as to their variety , ( ) that the number of indivisible particles comprehended under each difference of figures , is also incomprehensible , but not inexhaustible , as epicurus inconsiderately imagined . sect . iv. concerning the motions of atoms . to give the more light to this dark theorem , we are to praepossess our reader with two introductory observables ; ( ) that our praesent insistence upon only the motion of ato●s , doth not suppose our omission of their gravity ; but duely include the full consideration thereof : since their motion is the proper effect of their gravity , and that which doth chiefly bring it within the sphaere of our apprehension . ( ) that the genuine atomist doth worthily disavow all motion , but what plutarch in the name of epicurus , hath defined to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , migratio de loco in locum , the translation of a thing from one place to another . the suspicion of a chasme in our discourse , and the ambiguity imminent from the aequivocality of the term , motion , thus maturely praevented : we may more smoothly progress to our short animadversions on the conceptions of the ancients , touching the last general propriety of atoms , their congenial and intestine motion . herein we are to recognize their opinions , that concern ( ) the multiplicity , ( ) the perpetuity of motions essentially competent to atoms . as to the first ; they have , according to a general distinction , assigned to atoms a two-fold motion ; ( ) natural , whereby an atom , according to the tendency of its essential weight , is carried directly downward : ( ) accidental , whereby one atom justling or arienating against another , is diverted from its perpendicular descendence , and repercussed another way . the former , they called perpendicular , the other , reflex . the natural or perpendicular epicurus hath doubled again into 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ad perpendiculum , or as cicero ( de fato ) interprets it , ad lineam : and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ad declinationem . the accidental , or reflex hath also , according to the tradition of plutarch , ( . placit . . ) been by him subdivided into 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ex plaga , seu ictu ; and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ex concussione , or rather , ex palpitatione . so that , according to this special distinction , there must be four different sorts of motions assignable to atoms . for the perpendicular motion , we advertise ; that epicurus therein had no respect to any centre either of the world , or the earth ; for he conceded none such possible in the universe , which he affirmed of infinite extent : but to two contrary regions allowable therein , the one upward , from whence , without any terminus à quo , atoms flowed ; the other dow●ward , toward which , without any terminus ad quem , in a direct line they tended . so that , according to this wild dream , any coast from whence atoms stream , may be called above , and any to which they direct their course , below ; insomuch as he conceited the superfice of the earth , on which our feet find the centre of gravity in standing or progression , to be one continued plane , and the whole horizon above it likewise a continued plane running on in extent not only to the firmament , but the intire immensity of the infinite space . according to which d●lirament , if several weights should fall down from the firmament , one upon europe , another upon asia , a third upon africa , a fourth upon america ; and their motion be supposed to continue beyond the exteriors of the terrestrial globe : they could not meet in the centre thereof , but would transfix the four quarters in lines exquisitely parallel , and still descend at equal distance each from other , untill the determination of their motion in the infinite space , by the occurse and resistence of other greater weigh●● . for the declinatory motion ; we observe , that epicurus was by a kind of seeming necessity constrained to the fiction thereof ; since otherwise he had left his fundamental hypothesis manifestly imperfect , his principles destitute of a cause for their convention , conflictation , cohaerence , and consequently no possibility of the emergency of concretions from them . and , therefore , to what cicero ( in ● . de fin . ) objects against him , viz. that he acquiesced in a supposition meerly praecarious , since he could assign no cause for this motion of declination , but usurped the indecent liberty of endowing his atoms with what faculties he thought advantagious to the explanation of natures phaenomena in generation and corruption : we may modestly respond , by way of excuse not justification , that such is the ●●becillity of human understanding , as that every author of a physiological ●abrick , or mundane systeme , is no less obnoxious to the same objection , of praesuming to consign provinces ( for the phrase of cicero , is dare provincias principiis ) to his principles , then epicurus . for , in concretion● or complex natures , to determine on a reason for this or that sensible affection , is no desperate difficulty ; since the condition of praeassumed principles may afford it : but , concerning the originary causes of those affections inhaerent in and congenial to the principles of those concretions , all we can say , to decline a downright confession of our ignorance , is no more then this , that such is the necessity of their peculiar nature ; the proper and germane 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 remaining in the dark to us , and so our curiosity put to the shift of simple conjecture , unless we level our thoughts above principles , and acknowledge no term of acquiescence . and even the acute and perspicacious cicero , notwithstanding his reprehension of it in epicurus , is forced to avow the inevitability of this exigent , in express words , thus ; ne omnes à physicis irrideamur , si dicamus quicquam fieri si●e causa distinguendum est , & ita dicenaum ; ipsius individui hanc esse naturam , i● pondere & gravitate moveatur , eamque ipsam esse caussam , cur ita feratur , &c. nor is this crime of consigning provinces to his principles , proper only to epicurus ; but common also to the stoick , peripatetick , &c. since none of them hath adventured upon a reason of the heat of fire , the cold of water , the gravity of earth , &c. doubtless , had cicero been interrogated , why all the starrs are not carried on in a motion parallel to the aequator , but some steer their course obliquely ; why all the planets travel not through the ecliptick , or at least in a motion parallel thereto , but some approach it obliquely : the best answer he could have thought upon , must have been only this , ita natu●ae leges ●erehant ; which how much beseeming the perspicacity of a physiologist more then to have excogitated fundamentals of his own , endowed with inhaerent faculties to cause those diverse tendencies , we referr to the easie arbitration of our reader . concerning the accidental , or reflex mot●on , all that is worthy our serious notice , is only this ; that when epicurus subdivideth this genus into two species , namely 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ex plaga , and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ex concussione , and affirmeth that all those atoms which are ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) moved upward , pursue both sorts of this reflex tendency ; we are not to understand him in this sense , that both these kinds of reflex motion are opposite to the perpendicular , since it is obvious to every man , that atoms respective to their direct , or oblique incidence in the different points of their superfice , may make , or rather suffer or direct , or oblique resilitions , and epicurus expresly distinguisheth the motion from collision or arietation into that which pointeth upward , and that which pointeth sidewayes ; but in this , that he might constitute a certain generical difference , whereby both the species of reflex motion might be known from both the species of the perpendicular . for the further illustration of this obscure distinction , and to praevent that considerable demand , which is consequent thereto , viz. whether all the possible sorts of re●●ex motion are only two , the one directly upward , the other directly lateral : we advertise , that epicurus seems to have alluded to the most sensible of simple differences in the pulse of animals . for , as physitians , when the pulsifick faculty distends the artery so amply , and allows so great a space to the performance of both those successive contrary motions , the diastole and systole , as that the touch doth apprehend each stroke fully and distinctly , denominate that kind of pulse , 〈◊〉 ; and on the contrary , when the vibrations of the artery are contracted into a very little space as well of the ambient , as of time , so as they are narrow and confusedly praesented to the touch , they call it 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : so likewise epicurus terms that kind of rebound , or resilition , which by a strong and direct incurse and arietation of one atom against another , is made to a considerable distance , or continued through a notable interval of space , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ; and , on the contrary , that which is terminated in a short or narrow interval ( which comes to pass , when the resilient atom soon falls foul upon a second , and is thereby reviberated upon a third , which repercusseth it upon a fourth , whereby it is again bandied against a fifth , and so successively agitated , until it endure a perfect palpitation ) he styles 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . upon this our master galen may be thought to have cast an eye , when he said ( lib. de facult . nat . ) it was the opinion of epicurus , omnes attractiones per resilitiones atque implexiones atomorum fieri that all attractions were caused by the resilitions and implexions of atoms . which eminent passage in galen , not only assisted , but interpreted by another of plato ( magnetem non per attractionem , sed impulsionem agere , in timaeo ) of the same import ; hath given the hint to des cartes , regius , sir k. digby , and some other of our late enquirers , of supposing the attractive , rather impulsive virtue of the loadstone , and all other bodies electrical , to consist in the recess , or return of those continued effluvia , or invisible filaments of streated atoms , which are uncessantly exhaled from their pores . nor doth he much strain these words of gilbert [ effluvia illa tenuiora concipiunt & amplectuntur corpora , quibus uniuntur , & electris , tanquam extensis brachiis , & ad fontem prope invalescentibus effluviis , deducuntur ] who hath charged them with the like signification . as to the second , viz. the perpetuity of these motions adscribed to atoms ; we think it not a little material to give you to understand , at least to recognize that the conceptions of epicurus concerning this particular , are cozen germans to chimaera s , and but one degree removed from the monstrous absurdities of lunacy . for , he dreamt , and then believed , that all atoms were from all eternity endowed , by the charter , of their uncreate and independent essence , with that ingenite vigour , or internal energy , called gravity , whereby they are variously agitated in the infinite space , without respect to any centre , or general term of consistence : so as they could never discontinue that natural motion , unless they met and encountred other atoms , and were by their shock or impulse deflected into another course . that the dissilient or deflected atoms , whether rebounding upwards directly , or ad latus obliquely , or in any line intercedent betwixt those two different regions , would also inde●inently pursue that begun motion , unless they were impeded and diverted again by the occurse and arietation of some others floating in the same part of space . and , that because the revibrations , or resilitions of atoms regarding several points of the immense space , like bees variously interweaving in a swarm , must be perpetual : therefore also must they never quiesce , but be as variously and constantly exagitated eve● in the most solid or adamantine of concretions , though the sense cannot deprehend the least inquietude or intestine tumultuation therein ; and the rather in respect of those grotesques or minute inanities densely intermixed among their insensible particles . to explicate this riddle , we must praesent some certain adumbration of this intestine aestuation or commotion of atoms in concretions ; and this may most conveniently be done in melted mettals , as particularly in lead yet floating in the fusory vessel . to apparence nothing more quiet and calm : yet really no quicksand more internally tumultuated . for , the insensible particles of fire having penetrated the body of the crucible , or melting pan , and so permeating the pores of the lead therein contained ; because they cannot return back upon the subjacent fire , in regard they are uncessantly impelled by other ingeneous particles continually succeeding on their heels , therefore are they still protruded on , untill they disunite all the particles of the lead , and by the pernicity and continuation of this their ebullition , hinder them from mutual revinction and coalescence : and thereby make the lead a fluid , of a compact substance , and so keep it , as long as the succussion of igneous particles is maintained from the fire underneath . during this act of fusion , think we , with what violence or pernicity the atoms of fire are agitated up and down , from one side to another , in the small inanities interspersed among the particles of the lead ; otherwise they could not dissolve the compact tenour thereof , and change their positions so as to introduce manifest fluidity : and , since every particle of the lead , suffers as many various concussions , repercussions , and repeated vibrations , as every particle of fire ; how great must be the commotion on both sides , notwithstanding the seeming quiet in the surface of the lead ? but , because our sense , as well as our reason ; may have some satisfaction , touching the perpetual commotion of atoms , even in compositions ; we offer to exemplifie the same either in the spirit of halinitre , or that which chymists usually extract from crude mercury , tin , and sublimate codissolved in a convenient menstruum : for , either of these liquors being close kept in a luted glass , you may plainly perceive the minute moleculae , or seminarie conventions of atoms , of which it doth consist , to be uncessantly moved every way , upward , downward , transverse , oblique , &c. in a kind of fierce aestuation , as if goaded on by their inhaerent motor , or internal impulsive faculty , they attempted speedy emergency at all points , most like a multitude of flyes imprisoned in a glass vial. now , the argument that seems to have induced epicurus to concede this perpetual inquietude of atoms , was the inevitable mutation of all concrete substances , caused by the continual access and recess of their insensible particles . for , indeed , no concretion is so compact and solid , as not to contain within it self the possible causes of its utter dissolution ; yea , though it were so immured in adamant , as to be thought secure from the hostile invasion of any extrinsecal agent whatever . and the ruine of solid bodies ( i. e. such whose parts are of the most compact contexture allowable to concretions , ) cannot be so reasonably adscribed to any cause , as this ; that they are compacted of such principles , as are inde●inently motive , and in perpetual endeavour of emergency or exsilition : so that never desisting from internal evolutions , circumgyrations , and other changes of position ; they at length infringe that manner of reciprocal coaptation , cohaesion , and revinction , which determined their solidity , and thereby dissolving the compositum , they wholly emancipate themselves , obey their restless tendency at randome , and disappear . this faeculent doctrine of epicurus , we had occasion to examine and refine all the dross either of absurdity , or atheism , in our chapter concerning the creation of the world ex nihilo , in our book against atheism . however , we may not dismiss our reader without this short animadversion . the positions to be exploded are ( ) that atoms were eternally existent in the infinite space , ( ) that their motive faculty was eternally inhaerent in them , and not derived by impression from any external principle , ( ) that their congenial gravity affects no centre , ( ) that their declinatory motion from a perpendicular , is connatural to them with that of perpendicular descent , from gravity . those which we may with good advantage substitute in their stead , are ( ) that atoms were produced ex nihilo , or created by god , as the sufficient materials of the world , in that part of eternity , which seemed opportune to his infinite wisdom ; ( ) that , at their creation , god invigorated or impraegnated them with an internal energy , or faculty motive , which may be conceived the first cause of all natural actions , or motions , ( for they are indistinguishable ) performed in the world ; ( ) that their gravity cannot subsist without a centre ; ( ) that their internal motive virtue necessitates their perpetual commotion among themselves , from the moment of its infusion , to the expiration of natures lease . for , by virtue of these correctives , the poisonous part of epicurus opinion , may be converted into one of the most potent antidotes against our ignorance : the quantity of atoms sufficing to the materiation of all concretions ; and their various figures and motions to the origination of all their qualities and affections , as our immediately subsequent discourse doth professedly assert . the third book . chap. i. the origine of qualities . sect . i. that the sounding line of mans reason is much too short to profound the depths , or channels of that immense ocean , nature ; needs no other evictment but this , that it cannot attain to the bottom of her shallows . it being a discouraging truth , that even those things , which are familiar and within the sphere of our sense , and such to the clear discernment whereof we are furnished with organs most exquisitely accommodate ; remain yet ignote and above the moon to our understanding . thus , what can be more evident to sense , then the continuity of a body : yet what more abstruse to our reason , then the composition of a continuum ? what more obviously sensible then qualities : and yet what problem hath more distracted the brains of philosophers , then that concerning their unde , or original ? who doth not know , that all sensation is performed by the mediation of certain images , or species : yet where is that he , who hath hit the white , in the undoubted determination of the nature of a species , or apodictically declared the manner of its emanation from the object to the sensorium , what kind of insensible-sensative impression that is , which it maketh thereupon , and how being from thence , in the same instant transmitted to that noble something within us , which we understand not , it proves a lively transumpt , or type , and informs that ready judge of the magnitude , figure , colour , motion , and all other apparences of its antitype or original ? or , what hath ever been more manifest or beyond dubitation , then the reality of motion ? and yet we dare demand of galilaeo himself , what doth yet remain more impervestigable , or beyond apodictical decision , then the nature and conditions thereof . concerning the first of these aenigmatical quaestions , we have formerly praesented you no sparing account of our conjectural opinion : which we desire may be candidly accepted in the latitude of probability only , or how it may be , rather then how it is , or must be ; i. e. that it is , though most possible and verisimilous that every physical continuum should consist of atoms ; yet not absolutely necessary . for , insomuch as the true idea of nature is proper only to that eternal intellect , which first conceived it : it cannot but be one of the highest degrees of madness for dull and unequal man to praetend to an exact , or adaequate comprehension thereof . we need not advertise , that the zenith to a sober physiologists ambition , is only to take the copy of nature from her shadow , and from the reflex of her sensible operations to describe her in such a symmetrical form , as may appear most plausibly satisfactory to the solution of all her phaenomena . because 't is well known , that the eye of our grand master aristotles curiosity was levelled at no other point , as himself solemnly professeth ( in meteorolog . lib. . cap. . initio ) in these words : 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : i. e. cum autem de hisce , quae sensui pervia non sunt , satis esse juxta rationem demonstratum putemus , si ad id ●uod fieri possit ea reduxerimus , ex hisce quae in praesentia dicuntur , existimaverit quispiam de hisce maximè ad hunc modum usu venire . and evident it is that mons. des cartes never was more himself , that is , profoundly ingenious , then when he crowned his excellent principles of philosophy with this advertisement : a● quamvis forte hoc pacto intelligatur , quomodo res omnes naturales fieri potuerint ; non tamen ideo concludi debet , ipsas reverà sic factas esse : & sati● à me praestitum esse putabo , si tantum ea quae scripsi , talia sint , ut omnibus naturae phaenomenis accurate respondeant ; hoc enim ad usum vitae sufficiet . and , concerning the other three , which according to the natural order of their dependence , are successively the arguments of our next ensuing exercitations ; we likewise deprecate the same favourable interpretation , in the general : that so , though our attempts perhaps afford not satisfaction to others , yet they may not occasion the scandal of arrogance and obstinacy in opinion to our selves . by the quality of any concretion , we understand in the general , no more but that kind of apparence , or representation , whereby the sense doth distinctly deprehend , or actually discern the same , in the capacity of its proper object . an apparence we term it , because the quale or suchness of every sensible thing , receives its peculiar determination from the relation it holds to that sense , that peculiarly discerns it : at least from the judgment made in the mind according to the evidence of sensation . which doubtless was the genuine intent of democritus in that remarkable and mysterious text , recorded by galen ( in lib. . de element . cap. . ) thus : 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , &c. lege enim color , lege amaror , lege dulcor ; revera autem atomus , & inane , inquit democritus , existimans omneis qualitates sensibileis ex atomorum concursu gigni , quatenus se habent ad nos , qui ipsarum sensum habemus : natura autem nihil candidum esse , aut flavum , aut rubrum , &c. the importance of which may be fully and plainly rendred thus ; that since nothing in the universe stands possessed of a real or true nature , i. e. doth constantly and invariately hold the praecise ●uale , or suchness of their particular entity , to eternity ; atoms ( understand them together with their essential and inseparable proprieties , lately specified . ) and the inane space only excepted : therefore ought all other things , and more eminently qualities , in regard they arise not from , nor subsist upon any indeclinable necessity of their principles , but depend upon various transient accidents for their existence , to be reputed not as absolute and entire realities , but simple and occasional apparences , whose specification consisteth in a certain modification of the first matter , respective to that distinct affection they introduce into this or that particular sense , when thereby actually deprehended . not that democritus meant , in a litteral sense , that their production was determinable ex instituto hominum , by the opinionative laws of mans will ; as most of his commentators have inconsiderately descanted : but in a metaphorical , that as the justice , injustice , decency , turpitude , culpability , laudability of human actions , are determined by the conformity or difformity they bea● to the constitutions civil , or laws generally admitted , so likewise do the whiteness , blackness , sweetness , bitterness , heat or cold , of all natural concretions receive their distinct essence , or determination from certain positions and regular ordinations of atoms . and this easily hands us to the natural scope of that passage in laertius ; 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , esse atomos & inane universorum principia , caetera omnia lege sanciri : as also of another in empiricus ( . hypot. . ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , vere esse insectilia ac inane . however , if any please to prefer the exposition of magnenus , that democritus by that unfrequent and gentilitious phrase , nomo esse qualitates would have the determinate nature of any quality to consist in certa quadam lege , & proportione inter agens & patiens , in a certain proportion betwixt the agent and patient , or object and sensorium ; we have no reason to protest against his election . for we shall not deny , but what is ho●y to the palate of one man , is gall to another ; that the most delicious and poynant dishes of europe , are not only insipid but loathsome to the stomachs of the iapones ▪ who in health eat their fish boyled , and in sickness raw , as maffeus ( in libro de iaponum moribus ) reports ; that some have feasted upon rhubarb , scammony , and esula , which most others are ready to vomit and purge at the sight of ; that serpents are dainties to deer , hemlock a perfect cordial to goats , hellebor a choyce morsel to quails , spiders restorative to monkeys ▪ toads an antidote to ducks , the excrements of man pure ambre grise to swine , &c. all which most evidently declare the necessity of a certain proportion or correspondence betwixt the object and particular organ of sense , that is to apprehend and judge it . but since the notion of a quality is no rarity to common apprehension , every clown well understanding what is signified by colour , odour , sapour , heat , cold , &c. so far as the concernment of his sense we are no longer to suspend our indagation of their possible origine , in the general . which , were our atoms identical with the homoiomerical principles of anaxagoras formerly described , and exploded ; might be thought a task of no difficulty at all : in regard those consimilarities are supposed actually to contain all qualities , in the simplicity of their nature , or before their convention and disposition into any determinate concretion ; i. e. that colour , odour , sapor , heat , cold , &c. arise from colorate , odorate , sapid , hot , cold particles of the first catholique matter . but , insomuch , as atoms , if we except their three congenial proprieties , viz. magnitude ( which by a general interest , retains to the category of qualities ) figure , and motion ; are unanimously assumed to be exquales , seu qualitatis expertes , absolutely devoid of all quality : it may seem , at first encounter , to threaten our endeavors with infelicity , and damp curiosity with despair of satisfaction . and yet this giant at distance , proves a mere pygmie at hand . for , the nakedness , or unqualifiedness of atoms , the point wherein the whole difficulty appears radicated ; to a closer consideration must declare it self to be the basis of our exploration , and indispensably necessary to the deduction of all sensible qualities from them , when disposed into concrete natures . because , were any colour , odour , &c. essentially inhaerent in atoms ; that colour , or odour must be no less intransmutable then the subject of its inhaesion : and that principles are intransmutable , is implied in the notion of their being principles ; for it is of the formal reason of principles , constantly to persever the same in all the transmutations of concretions . otherwise , all things would inevitably , by a long succession of mutations , be reduced to clear adnihilation . besides , all things become so much the more decoloured , by how much the smaller the parts are into which they are divided ; as may be most promptly experimented in the pulverization of painted glass , and pretious stones : which is demonstration enough , that their component particles , in their elementary and discrete capacity , are perfectly destitute of colour . nor is the force of this argument restrained only to colour , as the most eminent of qualities sensible : but extensible also to all others , if examined by an obvious insistence upon particulars . now , having taken footing on the necessary incompetence of any sensible quality to the material principles of concretions : we may safely advance to our investigation of the reason , or manner how colour , and all other qualities may be educed from such naked and unqualified principles . and first we must have recourse to some few of the most considerable events consignable to atoms , as well as to their inseparable proprieties . the primary , and to this scope , most directly pertinent events of atoms , are only two , viz. 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , order and situation . that leucippus and democritus , besides those two eminent events , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , concretion , and secretion , from which the generation and corruption of all things are derived ; have also attributed unto atoms , two other as requisite to all alteration , i. e. the procreation of various qualities , namely order and position : is justifiable upon the testimony of aristotle ( in lib. de ortu & interitu ) however he was pleased ( in . metaphys . cap. . ) interpreting the abderitane terms of democritus , to adnumerate 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , figure , unto them , and thereupon inferr that atoms are different , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , i. e. aut rhysmo , quod est figura ; aut trope , quod est situs ; aut diathege , quod est ordo : & ( in metaphys . . cap. . ) to exemplifie this difference in letters of the alphabet ; saying that a and n differ in figure ; a n , and n a , in order ; and z n , in situation . which is the same with what empiricus ( . advers . phys . ) reports to have been delivered by epicurus . true it is , his disciple lucretius , exceeded him in the number of events assignable to atoms , in order to the emergency of all sensible qualities from them ; for he composing this distich intervalla , viae , connexus , pondera , plagae , concursus , motus , ordo , positura , figurae , confounds both events and conjuncts together : wherein he seems to have had more regard to the smoothness of his verses , then the methodical traction of his subject . for , motion , concurse , and percussion are the natural consequents of gravity : and distance and connexion are included in position ; and wayes or regions belong to order , as may be exemplified in the former letters , which respective to their remote or vicine position , and their change from the right to the left hand , exhibite to the sense various faces or apparences . that those two conjuncts , magnitude and motion , are necessarily to be associated to order and position ; is evident from hence , that if it be enquired , why there is in light so great a subtility of parts , as that in an instant it penetrates the thickest glass ; but so little in water , as that it is terminated in the superfice thereof : what more verisimilous reason can be alledged to explain the cause of that difference in two fluid bodies , then this , that the component particles of light are more minute , or have less of magnitude , then those of water ? and if it be enquired , why the aer , when agitated by the wind , or a fan , appears colder , then when quiet : what solution can be more satisfactory , then this , that by reason of its motion it doth more deeply penetrate the pores of the skin , and so more vigorously affect the sense ? however , if we confine our assumption only to these three heads , figure , order , and position ; we shall yet be able , without much difficulty , to make it out , how from them , either single , or diversly commixt , an infinite multiplicity of qualities may be created ; as may be most appositely explained by the analogy which letters hold to atoms . for as letters are the elements of writing , and from them arise by gradation , syllables , words , sentences , orations , books : so proportionately are atoms the elements of things , and from them arise by gradation , most exile moleculae , or the seminaries of concretions , then greater and greater masses successively , until we arrive at the highest round in the scale of magnitude . but we are restrained to an insistence only upon our heads assumed . as letters of divers figures , u , g , a , e , o , when praesented to the eye , carry different species , or aspects ; and when pronounced , affect the ear with as many distinct sounds : exactly so do atoms , respectively to the variety of their figures , and determinate contexture into this or that species , occurring to the organs of sight , hearing , smelling , tasting , touching , make divers impressions thereupon , or praesent themselves in divers apparences , or what is tantamount ) make divers qualities . ( ) as one and the same letter diversly posited , is divers to the sight , and hearing , as may be instanced in z , n , y , ● , b , d , p , q : so likewise doth one and the same atom , according to its various positions , or faces , produce various affections in the organs of sense . for instance , if the atome assumed be pyramidal : when the cone is obverted to the sensory organ , it must make a different impression upon it , from that which the base , when obverted and applyed , will cause . ( ) as the same two three or more letters , according to their mutation of site , or antecession and consequution , impart divers words to the eye , divers sounds to the ear , and divers things to the mind ; as et , te , is , si , sum , mus , roma , amor , maro , ramo , oram , mora , armo , &c. so also may two three , or more atoms , according to their various positions and transpositions , affect the sense with various apparences , or qualities . ( ) and as letters , whose variety of figures exceeds not those of the alphabet , are sufficient only by the variety of order , to compose so great diversity of words , as are contained in this , or all the books in the world : so likewise , if there were but diverse figures competent to atoms , they alone by variety of order , or transposition , would suffice to the constitution of as incomprehensible a diversity of qualities . but , when the diversity of their figures is incomparably greater : how infinitely more incomprehensible must that variety of qualities be , which the possible changes of their order may produce ? thus in the water of the sea , when agitated into a white froth , no other mutation is made , save only the situation and differing contexture of the parts thereof disposed by the included aer into many small bubbles ; from which the incident rayes of light ( which otherwise would not have been reflected in united ) are reflected in united and direct streams to the eye , and so creat a whiteness continued , which is but paler , or weaker light , which must disappeari mmediately upon the dissolution of the bubbles , and return of the p●rts of the water to their natural constitution of fluidity . and since we are fallen upon that eminent quality , colour ▪ we shall illustrate the obscure nativity thereof , in the general , by a most praegnant example . immerge into a glass vial of clean fountain water , set upon warm embers , half●n ounce more or less , according the quantity of water ) of the leaves of 〈◊〉 and after a small interval of time , instill into the infusion a few drops of the oil of tartar made per deliqu●um , which done , you shall perceive the whole mixture to become red. now , seeing that no one of the three ingredients , in their simple and divided state , do retain to that species of colour in the remotest degree of affinity ; from what original can we derive this emergent redness ? doubtless , only from hence ; that the water doth so penetrate , by a kind of discussion separate , and educe the smaller particle● of that substance , whereof the leaves of senna are composed , as that the particles of the oyl of tartar subtily perme●ting the infusion , totally after the contexture thereof , and so commove and convert its minute dissolved particles , as that the rayes of light from without falling upon them , suffer various refractions and reflections from their several obverted faces , and praesent themselves to the eye in the apparence of that particular colour . and to confirm you herein ; you need only instead of oyl of tartar , infuse the like proportion of oyl of vitriol into the same tincture of senna : for , thereupon no such redness at all will arise to the composition . which can be solved by no better a reason than this ; that the oyl of vitriol wants that virtue of commoving and converting the educed particles of the senna into such positions and order , as are determinately requisite to the incidence , refraction , and reflection of the rayes of light to the eye , necessary to the creation of that colour . on the contrary , instead of senna , infuse rose leaves in the water , and superaffuse thereto a few drops of the spirit of vitriol : and then the infusion shall instantly acquire a purple tincture , or deep scarlet ; when from the like or greater quantity of oyl of tartar instilled , no such event shall ensue . both which experiments collated are demonstration sufficient , that a red may be produced from simples absolutely destitute of that gloss , only by a determinate commixture , and position of their insensible particles : no otherwise then as the same feathers in the neck of a dove , or train of a peacock , upon a various position of their parts both among themselves , and toward the incident light , praesent various colours to the eye ; or as a peice of changeable taffaty , according as it is extended , or plicated , appears of two different dyes . the same may also be conceived of the caerule tincture caused in white wine by lignum nephriticum infused when the decoction thereof shall remain turbid and subnigricant . moreover , lest we leave you destitute of examples in the other orders of qualities , respondent to the remaining senses , to illustrate the sufficiency of figure , order and situation , to their production ; be pleased to observe . first , that lead calcined with the spirit of the most eager vinegre , so soon as it hath imbibed the moysture of the ambient aer , or be irrigated with a few drops of water , will instantly conceive so intense a heat , as to burn his finger that shall touch it . now , since both the calcined lead and water are actually cold , and no third nature is admixt , and nothing more can be said to be in them when commixt , that was in them during their state of separation ; whence can we deduce that intense heat , that so powerfully affecteth , indeed , misaffecteth the sense of touching ? quaestionless , only from this our triple fountain , i. e. from hence , that upon the accession of humidity , the acute or pointed particle of the spirit of vinegre , ( whereby the fixed salt of the lead was , by potential calcination , dissolved , and the sulphur liquated ) change their order and situation , and after various convolutions , or the motions of fermentations , obvert their points unto , and penetrate the skin , and so cause a dolorous compunction , or discover themselves to the organ of touching in that species of quality , which men call heat . the reason of this phaenomenon is clearly the same with that of a heap of needles ; which when confused in oblique , transverse , &c. irregular positions , on every side prick the hand that graspeth them : but if disposed into uniform order , like sticks in a fagot , they may be laterally handled without any asperity or puncture : or that of the bristles of an urchine , which when depressed , or ported , may be stroked from head to tayle , without offence to the hand ; but when erected or advanced , become intractable . by the same reason also may we comprehend , why aqua fortis , whose ingredients in their simple natures are all gentle and innoxious , is so fiery and almost invincible a poyson to all that take it : why the spirit of vitriol , freshly extracted , kindles into a fire , if confused with the salt of tartar : why the filings of steel when irrigated with spirit of salt , suffer an aestuation , ebullition , and dissolution into a kind of gelly , or paste : with all other mutations sensible , observed by apothecaries and chymists , in their compositions of dissimilar natures , from which some third or neutral quality doth result . secondly , that in the parts of an apple , whose one half is rotten , the other sound , what strange disparity there is in the points of colour , odour , sapour , softness , &c. qualities . the sound half is sweet in taste , fresh and fragrant in smell , white in colour , and hard to the touch : the corrupt , bitter , earthy or cadaverous , duskish , or inclinining to black , and soft . now to what cause can we adscribe this manifest dissimilitude , but only this : that the particles of the putrid half , by occasion either of contusion , or corrosion , as the procatarctick cause , have suffered a change of position among themselves , and admitted almost a contrary contexture , so as to exhibite themselves to the several organs of sense in the species of qualities almost contrary to those resulting from the sound half ; which upon a farther incroachment of putrefaction , must also be deturbed from their natural order , and situations in like manner , and consequently put on the same apparences , or qualities . for , can it be admitted , that the sound mo●ty , when it shall have undergone corruption , doth consist of other particles then before ? if it be answered , that some particles thereof are exhaled , and others of the aer succeeded into their rooms ; our assertion will be rather ratified , then impugned : because it praesumes , that from the egression of some particles , the subingression of others of aer , and the total transposition of the remaining , corruption is introduced thereupon ; and thereby that general change of qualities , mentioned . these instances , and the insufficiency of any other dihoties , to the rational explanation of them , with due attention and impartiality perpended ; we cannot but highly applaud the perspicacity of epicurus , who constantly held , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , that the motion of mutation was a species of local transition : and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 : concretum , quod secundum qu●litatem mutatur , omnino mutatur locali & transitivo motu eorum corporum , ratione intelligibilium , quae in ipsum concreverint . which empiricus ( . advers . phys. ) descanting upon , saith thus ; exempli caussâ , ut ex dulci fiat aliquid amarum , aut ex albo nigrum ; oportet moleculas , seu corpuscula quae ipsum constituunt , transponi , & alium , vice alterius , ordinem suscipere : hoc autem non contigerit , nisi ipsae moleculae , motione transitus , moveantur . et rursus , ut ex molli fiat quid durum , & ex duro molle ; oportet eas , quae illud constituunt , particulas secundum locum moveri : quippe earum extensione mollitur , coitione verò & condensatione durescit , &c. all which is most adaequately exemplified in a rotten apple . and this , we conceive , may suffice in the general for our enquiry into the possible origine of sensible qualities . chap. ii. that species visible are substantial emanations . sect . i. sensus non suscipere substantias , though the constant assertion of aristotle , and admitted into his definition of sense , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , sensus est id , quod est capax sensibilium specierum sine materia ; ( lib. . de anima , cap. ultim . ) and swallowed as an axiome by most of his commentators : is yet so far from being indisputable , that an intent examination of it by reason may not only suspect , but convict it of manifest absurdity . witness only one , and the noblest of senses , the sight : which discerns the exterior forms of objects , by the reception either of certain substantial , or corporeal emanations , by the sollicitation of light incident upon , and reflected from them , as it were direpted from their superficial parts , and trajected through a diaphanous medium , in a direct line to the eye : or , of light it self , proceeding in streight lines from lucid bodies , or in reflex from opace , in such contextures , as exactly respond in order and position of parts , to the superficial figure of the object , obverted to the eye . for the first of these positions , epicurus hath left us so rational ● ground , that deserves , besides our admiration of his perspicacity , if not our plenary adhaerence , yet at least our calm allowance of its verisimility , and due praelation to that jejune and frothy doctrine of the schools ▪ that species visible are forms without matter , and immaterial not only in their admission into the retina tunica , or proper and immediate organ of sight ; but even in their trajection through the medium interjacent betwixt the object and the eye . which argument , since too weighty , to be entrusted to the support of a gratis , or simple affirmation ; we shall endeavour to prop up with more then one solid reason . and this that we may , with method requisite to perspicuity , effect : we are to begin at the faithful recital of epicurus text , and then proceed to the explanation , and examination of it . reputandum est , esse in mundo quasdam effigies , ad visionem inservienteis , quae corporibus solidis delineatione consimiles , superant longè sua tenuitate quicquid est rerum conspicabilium . neque enim formari repugnat etiam in medio aere circumfusove spatio , hujusmodi quasdam contexturas : uti neque repugnat , esse quasdam in ipsis rebus , & maximè in atomis , dispositiones , ad operandum ejusmodi spectra , quae sunt quasi quaedam merae inanesque cavitates , & superficiales ▪ soliditatisvè expertes tenuitates . neque praeterea repugnat , fieri ex corporibus extimis effluxiones quasdam atomorum continenter a volantium in quibus i dem positus , idemque ordo , qui fuerit in solidis , superficiebusvè ipsorum , servetur : ut tales proind● effluxiones sint quasi formae , sive effigies , & imagines corporum , à quibus dimanant . tales autem formae sive effigies & imagines sunt , quas moris est nobis , ut idola , seu simulachra appellitemus . ex lib. . diogen . laertij . & versione gassendi . the importance of which , and the remainder of his judgment , concerning the same theorem , may be thus concisely rendred . without repugnancy to reason , it may be conceived ( ) that in the university of nature are certain most tenuious concretions , or subtle contextures , holding an exquisite analogy to solid bodies . ( ) that by these , occurring to the sense ; and thence to the mind , all vision , and intellection is made : for they are the same that the graecian philosophers call 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and the latine imagines , spectra , simulachra , effigies , and most frequently species intentionales . ( ) that among all the sundry possible wayes of the generation of these species visible , the two primary and most considerable are ( ) by their direption from the superficial parts of compound bodies , ( ) by their spontaneous emanation , and concretion in the aer ; and therefore those of the first sort are to be named 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and those of the second 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . ( ) that those images , which are direpted from the extreams of solid bodies , do conserve in their separated state the same order and position of parts , that they had during their united . ( ) that the ineffable or insuperable pernicity , whereby these images are transferred through a free space , depends upon both the pernicity of the motion of atoms , and their ten●ity or exility . for , the motion of atoms , while continued through the inane space , and impeded by no retundent , is supposed to be inexcogitably swift : nor are we to admit , that when an atom is repercussed by another directly arietating against it , and afterward variously bandied up and down by the retusion of others encountring it ; these partial or retuse motions are less swift , i. e. are performed in a space of time more assignable or distinguishable by thought , then if they were extended into one direct , simple , or uninterrupted motion . and for the second fundament , the extreme tenuity of atoms ; insomuch as these images are praesumed to be no more but certain superficial contextures of atoms : it cannot seem inconsequent , that their pernicity can know no remora . and thus much of epicurus text ; and the competent exposition thereof . it succeeds that we examine the relation it bears to probability ; refering the consideration of his spontaneous and systatical images , to the last section : and reducing our thoughts concerning the direpted and apostatical ( which are , indeed , the proper subject of our praesent disquisition ) to four capital points , viz. ( ) their an sint , or existence ; ( ) their quid sint , or proper nature ; ( ) their unde , or production ; ( ) their celerity of transmission . of the first , namely the existence of species visible ; this is sufficiently certified by the obvious experience of looking-glasses , water , and all other catoptrick or speculary bodies : which autoptically demonstrate the emission of images from things objected . for , if the object be removed , or eclipsed by the interposition of any opace body , sufficiently dense and crass to terminate them , the images thereof immediately disappear ; if the object be moved , inverted , expansed , contracted , the image likewise is instantly moved , inverted , expansed , contracted ; in all postures conforming to , and so undeniably proclaiming its necessary dependence upon its antitype . thus also , when in summer we shade our selves from the intense fervor of the sun , in green arbours , or under trees ; we cannot but observe all our cloaths tincted with a thin verdure , or shady green : and this from no other cause , but that the images or species of the leaves , being as it were stript off by the incident light , and diffused into the vicine aer , are terminated upon us , and so discolour our vestiments . not , as magirus would solve it ▪ qualitate , i. e. immateriali forma , qua aer , corpus 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , à folijs arborum viridibus imbuitur , tingitur , pingitur , ( comment . in phylologiam peripat . lib. . cap. . num . . ) and thus are the bodies of men sitting , or walking in a large room , infected with the colours of the curtains or hangings , when the sun strikes upon them : of which lucretius thus , nam jacier certè , atque emergere multa videmus , non solum ex alto , penitusque , ut diximus ante ; verum de summis ipsum quoque saepe colorem . et vulgo faciunt id lutea , russaque vela , et serruginea , cum magnis intenta theatris per malos volgata , trabeisque frementia flutunt . namque ibi concessum caveai subter , & omnem scendi speciem patrum , matrumque , deorumque , insiciunt , coguntque suo fluitare colore . ergo lintea de summo cum corpore fucum mittunt , effigias quoque debent mittere tenueis res quaeque , ex summo quoniam jaculantur utraeque &c. lib. . upon which reason also the admirable kircher hinted his parastatical experiment , of glossing the inside of a chamber , and all things as well furniture as persons therein contained , with a pleasant disguise of grass green , azure , crimson , or any other light colour ( for black cannot consist in any liquor , without so much density , as must terminate the light : ) only by disposing a capacious vial of glass , filled with the tincture of verdegrease , lignum nephriticum , or vermilion , &c. in some aperture of the window respecting the incident beams of the sun. ( art. magn. lucis , & umbrae , lib. . part . . mag●● , parastaticae experimento . ) concerning the second , viz. the nature of images visible ; we observe first , that epicurus seems only to have revived and improved the notion of plato , and empedocles , who positively declared the sensible forms , or visible species of things , to be 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , effluxiones quaedam substantiales : in that he denominates them aporrhea , and defines them to be most thin and only superficial contextures of atoms effluxed from the superficial parts of bodies , and jugi s●uore , by a continued stream em●ning from them into all the circumfused space . secondly , that the common opinion , most pertinaciously patronized by alexander the peripatetick , and scaliger , with the numerous herd of aristotelea●s ( whom it is as easie to convert , as nominate ) is , that visible species are mera accidentiae , simple pure accidents , that neither possess , nor carry with them any thing of matter , or substance ; and yet being transmitted through a diaphanous medium from solid objects , they affect the organ of sight , are reflected from polite and speculary bodies , &c. here we are arrested with wonder , either how these great masters of learning could derive this wild conceit from their oracle , aristotle ; when introth all they could ground upon his authority of this kind , is desumable only from these words of his , colorem rei visibilis movere perspicuum actu , quod deinceps oculum moveat : or how they could judge it consentaneous to reason , that those affections should be attributed to meer accidents , which are manifestly competent only to meer substances . for , to be moved or to be the subject of local motion , to be impinged against , and reflected from , or permeate a body ; to be dilated , contracted , inverted , &c. cannot consist , nor indeed by a sober man be conceived , without absolute substantiality . some there are , we confess , who tell us , that they kindled this conceit from sundry scattered sparks blended both in his general discourses of motion and alteration , and particular enquiries into the nature of dreams , and sounds , in his problems : and these , thereupon , most confidently state the whole matter , thus . that the visible object doth first generate a consimilar species in the parts of the aer next adjacent ; that this embryon species doth instantly generate a second in the parts of the aer next to it , that generates a third , that third a fourth , and so they generate or spawn each other successively in all points of the medium , untill the last species produced in the aer contiguous to the horny membrane of the eye , doth therein produce another ; which praesents to the optick nerve the exact delineations and pourtraiture of the protoplast , or object . to cure the schools of this delirium , our advice is , that they first purge off that faeculent humor of paedantism , and implicite adhaerence to authority ; and then with clean stomachs take this effectual alterative . if the visible species of objects be , as they define ; meer accidents , i. e. immaterial : we demand ( ) what doth creat them ? not the object ; since that hath neither power , nor art , nor instruments , to pourtray its own counterfeit on the table of the contiguous aer . ( ) what doth conserve and support them when pourtray'd ? not the aer ; since that is variously agitated , and dispelled by the wind , and commoved every way by light pervading it : and yet the species of objects are alwayes transmitted in a direct line to the eye . ( ) what can transport them ? neither aer , nor light : since it is of the formal reason of an accident , not to be removed or transmitted but in the arms of it subject . nor can the same numericall species be extended through the whole space of the medium ; because it is repugnant to their supposition : and themselves affirm the transmigration of an accident from one subject to another , impossible . ( ) is the species changed and multiplied by propagation ? that 's if not an impossibility absolute , yet a difficulty inexplicable ; first because no man ever hath , nor can explain the modus propagationis , the manner of their propagation : secondly , since the parts of space intermediate betwixt the object and the eye , though but at a small distance removed , are innumerable ; and a fresh propagation must be successively in each of those parts ; and the space of time required to each single propagation is a moment ; certainly it must be long before the propagation could attain to so small a part of space , as is aequal to one digit . if so ; how many hours would run by , after the suns emergency out of an eclipse , before the light of it would arrive at our eye ? since , as the moments , or points of space betwixt it and us are more then innumerable ; so likewise must the moments , or points of time , while a fresh species is generated in each point of that vast space , be more then innumerable : and yet we have the demonstration of the most scientifick of our senses , that the light of the sun is darted through that immense space , in one single moment . ( ) what is the material of these species , or whether is the 〈…〉 first species educed out of nothing ? that 's manifestly absurd ; because above the power of nature : and to recur to any other power superior to hers , is downright madness . ( ) or , ex materiae potentia , out of some secret energie of the matter of the medium ? that 's unconceivable ; for we dare the whole world to define , what kind of power that is , supposed inhaerent in the medium ( aer , water , glass , or any other 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) that can be actuated so expeditely into the production of infinite several species , in a moment . from one and the same part of aer , in one and the same moment , how can be educed the different species not only of the sun and a s●●ne , of a man and a stock , of a head and a foot ; but even of two absolute contraries , snow and pich ? ( ) if visible species contain nothing of matter ; how can they with such insuperable velocity be projected on a speculary body , and recoyl back from it to so great a distance , as is commonly observed , even in the repercussion , or rather reflection of a species from a concave glass : how consist of various parts , and conserve the order and position of them invariate , and the colours of each clearly inconfused , through the interval of the medium ? how be really ampliated , contracted , deflected , inverted , &c. all which are properly and solely congruent to bodies or entities consisting of matter ? ( ) but all these and many more as manifest incongruities and open absurdities may be praevented by the assumption of the more durable and satisfactory hypothesis of epicurus : for conceding the visible species of objects to be substantial effluxes , it can be no difficulty to solve their trajection , impaction , refraction , reflexion , contraction , diduction , inversion , &c. nor is it oppugnable by the objection of any dif●●culty more considerable , then that so insultingly urged by alexander the peripatetick : quanam ratione fi●ri possit , ut ex tot , tantisque effluentibus particulis , unumquodque adspectabilium non celerit●r absumatur ? how can it consist with reason , since the visible species are praesumed to be substantial effluviaes , that any the most solid and large adspectable body should not in a short time be minorated ▪ 〈◊〉 wholly exhausted by the continual deperdition of so many particles ? ( in comment ▪ in lib. de sensu & sensili , cap. . & epist. . ad dioscor . ) which yet is not so ponderous , as not to be counterpoysed by these two reasons , ( ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , accrescere ipsis adspectabilibus advenientia ex opposito corpuscula alia ; that the decay is praevented by the apposition and accretion of other minute particles succeeding into the rooms of the effluxed ; so that how much of substance decedes from the superficial parts of one body towards others , as much accedes to it by the advent of the like emanations from others , and thereupon ensues a plenary compensation . nor can it diminish one grain of the weight of this solution , to rejoyn ; that the figures of adspectables must then be changed : because the substantial effluxes which accede , cannot be in point of figure , order , and position of parts exactly consimilar to those which recede . for , though there be a dissimilitude in figure , betwixt the deceding and acceding particles ; yet , in so great a tenuity of particles , as we suppose in our substantial species , that can produce no mutation of figure in the object deprehensible by the sense : for many things remain invariate to the eye , which are yet very much changed as to figure , in the judgment of the understanding ; as may most eminently be exemplified in the change that every age insensibly stealeth upon the face of man. ( ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , tenuitatem simulachrorum esse omnem modum excedentem , the tenuity of these emanant images is extreme● and therefore the uninterrupted emission of them , even for many hundreds of years , can introduce no sensible either mutation of figure ; or minoration of quantity in the superficies of the emittent . which averrhoes ( at least the author of that book , destructionis destructionum , fathered upon him ) had respect unto , when he said ; neminem agniturum decrementum in sole factum , tametsi ab eo circum deperierit quantitas pa●mi , aut etiam major . to approach some degrees nearer in our comprehension to the almost incomprehensible tenuity of these substantial emanations , that essence the visible images of objects ; let us first , conceive them , with lucretius , to be , quasi membranae summo de corpore rerum dereptae , certain excortications , or a kind of most thin films , by the subtle fingers of light , stript off from the superficial extremes of bodies ; for alexander himself calls them 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , pelliculae & membranulae , & apuleius exuviae , because as the slough or spoil of a snake , is but a thin integument blancht off the new ●kin , and yet representing the various spots , scales , magnitude , figure &c. thereof : so likewise do the visible species , being meer decortications , or sloughs blancht off from bodies , carry an exact resemblance of all 〈◊〉 and colours in the exteriours thereof . secondly , assume the smallest of things visible , the foot of an hand-worm , for the object . for conceding the species emanant from it , which is deprehensible by a microscope , to consist only of those atoms , which cohaering only secundum la●●●a , and non 〈…〉 , laterally and not profound●● constitute the 〈◊〉 and then we cannot deny , that this species must be by many 〈…〉 thinner th●n the foot , or object it 〈◊〉 . thirdly , exemplifie the ineffable tenuity of these excortications , in those round films of wax that are successively lickt off by the flame of a tapour accended . for , having supposed , that one inch of a wax candle may suffice to maintain its flame , for the space of an hour : let us thus reason . since the diminution of that inch , perpendicularly erected , is uncessant , i. e. that there is no distinguishable moment of time , wherein there is not a distinct round of wax taken off the upper part thereof , by the depredatory activity of the flame : how many must the round films of wax be , that are successively direpted ? certainly , as many as there are distinguishable points , or parts in the part of the aequator , or ambite of the primum mobile , successively interjacent toward the meridian . and if , in stead of that vast heaven , the primum mobile , you think it more convenient to assume the terrestrial globe ( whose magnitude , in comparison of the other , amounts not above a point ) observe what may be thence inferred . since , according to the supputation of snellius and gassendus , the ambite of the earth is commensurable by italian miles ; and the part thereof makes miles , and so paces , and so feet , each whereof is again subdivisible into sensible parts : it follows , that as the product , or whole number of these parts in the part of the circumference of the globe terrestrial ariseth to ; so likewise must the distinct membranules of wax successive derepted from the inch of candle in the space of an hour fulfil the same high number of . and if so , pray how incomprehensible thin must each of them be ? if this example seem too gross to adumbrate the extreme tenuity of our species ; be pleased to exchange the wax tapour of an inch diameter , for solomons brasen sea , filled with oyl , and an inch of cotten weeck perpendicularly immersed , and at the upper extreme accensed , in the middle thereof . for , insomuch as the decrement of the oyl in altitude must be uncessant , as is the exhausting activity of the flame , there being no instant of time , wherein its diminution is interrupted ; and that , should the flame constantly adhaere to the weeck for hours , without extinction , the space of the oyls descent from the margin of the vessel could not in crassitude equal that of a piece of lawn , or a spiders web : certainly the number of rounds of oyl successively delibrated by the flame , in that constitute time , must require a far greater number of cyphers to its calculation . which would you definitely know ; 't is but computing the distinguishable points of time in hours , during which the flame is supposed to live , and you have your desire ; and we ours , as to the conjectural apprehension of the tenuity of each of them . lastly , let us argue à simili , and guess at the tenuity of a visible , from that of an odorable species . how many aromaticks are there , that for many years together , emit fragrant exhalations , that replenish a considerable space of the ambient aer ; and gratefully affect the nostrils of all persons , within the orb of projection : and yet cannot , upon the exactest statick experiment , or trutination of the scate , be found to have amitted one grain of quantity ? now if we consider , how crass the emanation of an aromatick , or an odorous anathymiasis , is comparatively to the substance of a visible species ( for no meaner a philosopher then gassendus , whose name sounds all the liberall sciences , hath conceived ; that the visible images effluxing from an apple in a whole year , if all cast into one bulk , would not exceed that of the odorous vapour exhaled from it in one moment ) we shall not gainsay , but a solid body may constantly maintain an emanation of its images visible , for many hundreds of years , from its superficial parts , without any sensible abatement of quantity , or variation of figure . to which we shall superadd only this ; that should we allow these substantial effluxes , that are supposed to constitute the visible species , to amount in many hundred years , to a mass deprehensible by sense , in case the collection of them all into one were possible : yet would it be so small , as to elude the exactest observation of man ; for , who that hath perchance weighed a piece of marble , or gold , and set down the praecise gravity thereof in his life time , can obtain a parrol from the grave and return to complete his experiment ; after the deflux of so many ages , as are required to fulfill the sensibility of its minoration ? concerning the third , viz. the production of species visible ; epicurus text may be fully illustrated by this exposition . that a solid body , so long as environed with a rare or permeable space , may be conceived without alogie , freely to emit its images : because it hath atoms ready in the superfice , that being actuated by their coessential motive faculty , uncessantly attempt their emancipation , or abduction ; and those so exile , that the ambient cannot impede their emanation . ( ) that in regard they conserve the delineations both of the depressed and eminent parts in the superfice of the antitype , or object , after their efflux therefrom : therefore do the images deceding from it become configurate of atoms cohaerently exhaling in the same order and position that they held among themselves , during their contiguity , or adhaesion . which also satisfies for the praesumed meer superficiality , i. e. improfundity of the species : because it is deraded only from the extremities of the object . ( ) that , forasmuch as no cause can be alledged , why the particles of the image should , in their progress through a pervious medium to considerable distance , be deturbed or discomposed from that contexture , or order and situation , which they obtained from the cortex or outward film of their solid original : therefore do they invariately hold the same configuration , untill their arrival at the eye . which to familiarize , we are to reflect upon a position or two formerly conceded , viz. that atoms are , by the impulse of their ingenite motion , variously agitated even in concretions most compact ; and yet cannot without difficulty expede themselves from the interior or central parts , because of their mutual revinction , or complication : but for those in the exterior or superficial parts , they may , upon the least evolution disingage themselves , having no atoms without to depress , but many within to express or impel them . ( ) that , since the motion of all atoms , when at liberty to pursue the tendency of their motive faculty , is aequivelox : hence is it , that those atoms which exhale from the cavities or deprest parts of the superficies of any concretion , and those which exhale from the prominencies , or eminent parts , are transferred together in that order , that they touch not , nor crowd each other , but observe the same distance and decorum , that they had in their contiguity to , and immediate separation from the superficies . so that the antecedent atoms cannot be overtaken , or praevented by the consequent : nor those farther outstrip these , then at the first start . ( ) that the emanation of visible images is continent , i. e. that one succeeds on the heels of another , jugi quodam fluore , in a continued stream more swiftly then that thought can distinguish any intermediate distance . so that , as in the exsilition of water from the cock of a cistern perpetually supplied by a fountain , the parts thereof so closely succede each other , as to make one continued stream , without any interruption observable : are we to conceive the efflux of images to be so continent , that the consequent press upon the neck of the antecedent so contiguously , as the eye can deprehend no discontinuity , nor the mind discern any interstice in their flux . and this ushers us to the reason , why apuleius , discoursing in the dialect of epicurus , saith , profectas à nobis imagines , velut quasdam exuvias jugifluore manare . ( ) and lastly , that a visible image doth not so constantly retain its figure , and colours , as not to be subject to mutilation and confusion , if the interval betwixt its original and the eye be immoderately large : as may be exemplified in the species of a square tower , which by a long trajection through the aer , hath its angles retused , so that it enters the eye in a cylindrical figure . this epicurus expresly admitted in his 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , confusam interdum evadere imaginem . which ought to be interpreted not only of the detriment sustained in its long progress through the medium , but also of that which may arise from some perturbation caused in the superfice of the exhalant . concerning the fourth , viz. the celerity of their motion ; this will epicurus have to be 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , inexsuperabilem , swift in the highest degree : and his reason is , because such is the pernicity of atoms , when enfranchised from concretions , and upon the wings of their gravity . lucretius most appositely compares the celerity of images in their trajection , to that of the beams of the sun , which from the body thereof are darted to the superfice of the earth in an instant , or so small a part of time , as none can be supposed less . and this we may clearly comprehend , if we observe that moment when the sun begins its emergency from the discuss of the moon , in an eclipse ; for in the same moment , we may discern the image of its cleared limbus , appearing in a vessel of water , respectively situate . and yet we say , the celerity of their trajection , not , with the vulgar , the instantaneous motion : because we conceive it impossible , that any moveable should be transferred to a distant place , in an indivisible moment , but in some space of time , though so short as to be imperceptible ; because the medium hath parts so successively ranged , that the remote cannot be pervaded before the vicine . and thus have we concisely commented upon the consider ables comprehended in the text of epicurus , touching apostatical images visible ; and thereupon accumulated those reasons , which justifie our praelation of this his opinion , to that not only less probable , but manifestly impossible one of the aristoteleans : so that there seems to us only one consideration more requirable to complete its verisimility , and that is touching the facility of the abduction of visible images from solids . we confess , that epicurus supposition , of the spontaneous evolution and consequent avolation of atoms from the extremes of solid concretions ; is not alone extensible to the solution of this difficulty : and therefore we must lengthen it out with that consentaneous position of gassendus ( de apparente magnitudine solis humilis & sublimis , epist. . pag. . ) lucem sollicitare species , that light doth sollicite and more then excite the visible species of objects , as well by agitating the superficial atoms of concretions , as by carrying them off in the arms of its reflected rayes . for , that light is intinged not only with colours , which it pervades , but also with those , which it only superficially toucheth upon , provided the colorate body be compact enough to repercuss it ; all opace and speculary bodies , on which its beams are either trajectly , or reflextly impinged , sensibly demonstrate . and though it may be objected , that the sollicitation of light is not necessary to the dereption , or abduction of images visible ; because it is generally praesumed , that they continually emane from objects , and so as well in the thickest darkness , as in the meridian light : it must notwithstanding be confest , that they are unprofitable to vision , unless when they proceed from an object illustrate ; and consequently that they flow hand in hand with the particles of light reflected from it superfice . which truly is the reason why the eye that is posited in the dark doth well discern objects posited in the light ; but that which is in the light hath no perception at all of objects in the dark . and therefore whoso shall affirme , that visible species are not emitted from bodies , unless light strike upon them , and being repercussed , carry their superficial atoms , which constitute the visible species , off from them , in direct lines towards the eye : though he may perhaps want a demonstration , yet not the evidence of experience and probability , to credit his paradox . nor is there , why we should opinion , that only the primary , or first incident light is reflected ; because light emaneth from the lucid , in a continued fluor , so that the praecedent particles are still contiguously pursued by the consequent : and hence is it that light is capable of repercussions even to infinity , if solid and impervious bodies could be so disposed , as that the first opposed might repercuss it on the second , the second reflect it to the third , the third to the fourth , &c. successively , so long as the fluor should be continued , and no eclipse intervene . for , the reason , why light , formerly diffused , doth immediately disappear , upon the intervention of any body , that intersects it stream ; is really the same with that , wherefore water exsilient from the tube of a cistern , in an arched stream , doth immediately droop and fall perpendicularly , upon the shutting of the cock : the successive flux of those parts of water , which , by a close and forceable pressure on the back of the praecedent , maintained the arcuation of the stream , being thereby praevented , and the effluxed committed to the tendency of their gravity . and the reason , why by the mediation of a small remainder of light , after the intersection of its fluor from the lucid fountain , we have an imperfect and obscure discernment of objects ; is no more then this : that only a few rayes , here and there one , are incident upon and so reflected from the superfice thereof , having touched upon only a few scattered particles , and left the greater number untoucht ; which therefore remain unperceived by the eye , because there wanted light sufficient to the illustration of the whole , and so to the excitement and emission of a perfect species . sect . ii. there is yet a second sort of images visible , which though consistent of the same materials with the former ; are yet different in the reason of their production , according to the theory of epicurus . for , as the former are perfectly substantial , being corporeal effluviaes , by a kind of dereption as it were blancht from the extremes of concretions : so likewise are these of the second genus , perfectly substantial , being certain concrements or coagmentations of atoms in the aer , representing the shapes of men , beasts , trees , castles , armies , &c. not caused by an immediate dereption from such solid prototypes , but a spontaneous convention and cohaesion of convenient particles . so that if we only call them , spontaneous systatical representations ; we shall not only import the disparity of their creation to that of the derepted apostatical ones , but also afford a glimpse of their abstruse nature . of these , all that can be brought to lye in lines parallel to our praesent theorem , doth concern only their existence : and that may be evicted by the conspiring testimonies of many authors , whose pens were not dipt in the fading ink of meer tradition , nor their minds deluded with the affectation of fabulous wonders . among which our leasure will extend to the quotation of only two , most pertinent and significant . diodorus siculus ( lib. . ) speaking of certain spectraes ; spontaneously conceited , and at set seasons of the year exhibiting themselves to travellers in the regions of africa , beyond the quick-sands and cyrene ; saith thus : 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ; quandoque , ac praesertim vigente tranquillitate aeris , conspiciuntur per aerem concrementa quaedam , forma● animalium omnis generis referentia . ipsorum nonnulla quietè se habent , nonnulla verò motionem subeunt . quinetiam interdum insequentes fugiant , interdum fugientes insequuntur , &c. and damascius ( in vita isidori philosophi , apud photium ) declaring the common report about that memorable 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or prodious aereal representation , annually beheld in the lower region of the aer , imminent upon that arm of the adriatick sea , that runs up betwixt messana in sicily , and rhegium julium in calabria ; delivers it thus : nostra tempestate narrarunt homines bonae fidei , juxta siciliam in campo nominato tetrapyrgio , & in aliis non paucis locis , videri equitum pugnantium sin ulacra ; idque maximè aestatis tempore , cum ardentissimus est meridies ; &c. concerning the verity of this report , the most curious athanasius kircherus having some doubt ; purposely takes a long journey from rome to messana and thence crosseth over to rhegium , at the opportune time for its observation . where what he beheld , and by what physical reasons he solved the wonderment ; we have thought worthy your patient notice , to extract from his excellent discourse thereupon ( in cap. . magiae parastaticae , parastasi . naturae . ) morgana rheginorum . in the midst of summer , when the sun boyls the tyrrhene ocean with most fervent rayes , then is it , that wanton nature entertains the wondring eyes of the inhabitants of rhegium , a town in calabria most ancient and no less famous for having been the seat of many philosophers , with a prodigious spectacle in the aer . there may you , whether with more delight , or wonder , is not soon determined , behold a spacious theatre in the vaporous aer , adorned with great variety of scenes , and catoptrick representations ; the images of castles , palaces , and other buildings of excellent architecture , with sundry ranges of pillars , praesented according to the rules of perspective . this scene withdrawn , upon the sayling by of the cloud , there succeeds another , wherein , by way of exquisite landskip , were exhibited spacious woods , groves of cypress , orchards with variety of trees , but those artificially planted in uniform rows like a perfect phalanx , large meadows , with companies of men , and herds of beasts walking , feeding , and couching upon them : and all these with so great variety of respondent colours , so admirable a commixture of light and darkness , and all their motions and gestures counterfeited so to the life , that to draw a landskip of equal perfection seems impossible to human industry . it may well be conceived , though not easily exprest , how much this parastatical phantasm ( which the inhabitants of rhegium call morgana ) hath excruciated the greatest wits of italy , while they laboured to explore a reason for the apparence of such things in the cloud , as were not found either on the shore , or adjacent fields . this much encreased the ardor of curiosity in me , so that crossing over from messana to rhegium , at the usual time of the apparition , i examined all the circumstances thereof , together with the situation of the place , the nature and propriety of the soyl , and the constitution of the vapours arising from the sea : and examining my observations by physical and optical reasons , i soon detected the causes of the whole phaenomenon . first i observed the mountain called tinna , on the sicilian side , directly confronting rhegium , to run along in a duskish obscure tract upon pelorus ; and the shores subjacent , as also the bottom of the sea , to be covered with shining sand , being the fragments of selenites , antimony , and other pellucid concretions , devolved from the eminent parts of the land , the contiguous hills , that are richly fraught with veins of those minerals . then i observed that these translucid sands , being , together with vapors from the sea and shore , exhaled into the aer , by the intense fervor of the sun ; did coalesce into a cloud , in all points respondent to a perfect polyedrical , or multangular looking-glass : the various superficies of the resplendent granules , making a multiplication of the species ; and that these , being opacated behind by crass and impervious vapours , directly facing the mountains , did make reflection of the various images of objects respective to their various positions to the eye . the several rows of pillars in the aereal scene are caused by one single pillar , erected on the shore ; for being by a manifold reflection from the various superficies of the tralucent particles , opacated on the hinder part by dense vapours , in the speculary meteor , it is multiplyed even to infinity . no otherwise then as one single image , posited betwixt two polyedrical looking-glasses , confrontingly disposed , is so often repercussed or reflected from superfice to superfice , that it exhibiteth to the eye almost an infinite multitude of images exactly consimilar . thus also doth one man standing on the shore , become a whole army in the cloud ; one beast , a whole herd , and one tree a thick-set grove . as for the vanishing of this first scene , and the succession of a second , adorned with the representations of castles , and other magnificent structures ; the cause hereof is this : since the eye of the spectator hath its sight variously terminated in the several speculary superficies of the cloud , that is in perpetual motion according to the impulse of the wind ; it comes to pass , that according to the rules of the angles of incidence and reflection , divers species are beheld under the same constitute angle , and as the speculary vapour doth reflect them toward the eye , which divers species are projected from objects conveniently situate ; and particularly from the castle on the ascent towards rhegium from the place of our prospect . some , perhaps , may judge our affirmation , of the elevation of those shining grains of vitreous minerals into the aer , by the meer attraction of the sun ; and the coalition of them there with the cloud of vapours : to be too large a morsel , to be swallowed by any throat , but that cormorant one of credulity . if so , all we require of them , is only to consider ; that hairs , straws , grains of sand , fragments of wood , and such like festucous bodies , are frequently found immured in hailstones : which doubtless , are sufficient arguments , that those things were first elevated by the beams of the sun , recoyling from the earth , into the middle region of the aer , and there coagmentated with the vapours condensed into a cloud , and frozen in its descent . now this solution of the morgana , acquires the more of certitude and auctority from hence ; that in imitation of this natural prodigious ostent , or aereal representation , kircher invented a way of exhibiting an artificial one , by the fragments of glass , selenites , antimony , &c. stewed in an iron trough , and vapours ascending from water superaffused , and terminated by a black curtain superextended . the full description of which artifice , he hath made the subject of his . parastasis in magia parastat . cap. . chap. iii. concerning the manner and reason of vision . sect . i. among the many different conceptions of philosophers , both ancient and modern , touching the manner and reason of the discernment of the magnitude , figure , &c. of visible objects by the visive faculty in the eye ; the most considerable are these . ( ) the stoicks affirmed , that certain visory rayes deradiated from the brain , through the slender perforations of the optick nerves , into the eye , and from thence in a continued fluor to the object ; do , by a kind of procusion , and compression , dispose the whole aer intermediate in a direct line , into a cone , whose point consisteth in the superfice of the eye , and base in the superfice of the object . and that , as the hand by the mediation of a staff , imposed on a body , doth , according to the degrees of resistence made thereby either directly , or laterally , deprehend the tactile qualities thereof , i. e. whether it be hard , or soft , smooth or rough , whether it be clay , or wood , iron , or stone , cloth , or leather , &c. so likewise doth the eye , by the mediation of this aereal staff , discern whether the adspectable object , on which the basis of it resteth , be white or black , green or red , symetrical or asymetrical in the figure of its parts , and consequently beautiful or deformed . ( ) aristotle , though his judgment never acquiesced in any one point , as to this particular , doth yet seem to have most constantly inclined to this ; that the colour of the visible doth move the perspicuum actu , i. e. that illustrate nature in the aer , water , or any other 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , transparent body ; and that , by reason of its continuity from the extremes of the object to the eye , doth move the eye , and by the mediation thereof the internal sensorium or visive faculty , and so inform it of the visible qualities thereof . so that , according to the descant of those , who pretend to be his most faithful interpreters , we may understand him , to have imagined the colour of the object to be as it were the hand ; the diaphanous medium as it were the staff ; and the eye as it were the body on which it is imposed and imprest : è diametro opposite to the conceit of the stoicks , who suppose the eye to supply the place of the hand ; the aer to analogize the staff ; and the object to respond to the body on which it is imposed and imprest . ( ) the pythagoreans determined the reason of vision on the reflexion of the visive rayes , in a continued stream emitted from the internal eye , to the visible , back again into the eye ; or , more plainly , that the radious emanations from the eye , arriving at the superfice of the object , are thereby immediately repercussed in an uninterrupted stream home again to the eye , in their return bringing along with them a perfect representation thereof , as to colour , figure and magnitude . ( ) empedocles , though admitting ( as we hinted in the next praeceding chapter ) substantial effluxes , from the visible to the organ of sight ; doth also assume the emission of certain igneous or lucid spirits from the organ to the object : supposing the eye to be a kind of glass lantern , illustrate , and illustrating the visible , by its own light. ( ) plato , though he likewise avouched the emanation of corporeal effluviaes from the object ; doth not yet allow them to arrive quite home at the eye : but will have them to be met half way by rayes of light extramitted from the eye : and that these two streams of external and internal light encountring with some renitency reciprocal , do recoyl each from other , and the stream of internal light resilient back into the eye , doth communicate unto it that particular kind of impression , which it received from the stream of extradvenient light , in the encounter ; and so the sentient faculty comes to perceive the adspectable form of the object , at which the radius of internal light is levelled . this we judge to be sense of his words ( in timaeo , circa finem tertiae partis ) simulachrorum , quae vel in speculis oboriuntur , vel in perspicua , laevique cernuntur superficie ; facilis assecutio est . nam ex utriusque ignis , tam intimi , quam extra positi communione , ejusque rursus consensu , & congruentia , qui passim terso , laevique corpori accommodatus est ; necessari● haec omnia oriuntur , quam ignis oculorum cum eo igne , qui est è conspecto effusus , circa laeve nitidumque corpus sese confundit . ( ) epicurus , tacitely subverting all these , foundeth the reason of vision , not in any action of the intermediate aer , as the stoicks and aristotle ; nor in any radious emanation from the eye to or toward the object , as the pythagoreans , empedocles , and plato : but , in the derivation of a substantial efflux from the object to the eye . ( ) and as for the opinion of the excellent monsieur des cartes , which with a kind of pleasant violence , hath so ravisht the assent of most of the students of physiology , in the praesent age , especially such as affect the accommodation of mechanick maxims to the sensible operations of nature ; that their minds abhor the embraces of any other : those , who have not heedfully perused his dioptricks , may fully comprehend it in summary , thus . for sensation in common , he defines it to be a simple perception , whereby a certain motion , derived from a body conveniently objected , communicated , by impression , to the small fibres , or capillary filaments of a nerve , and by those , in regard of their continuity , transmitted to the tribunal , or judicatory seat of the soul , or mind ( which he supposeth to be the glandula pinealis , in the centre of the brain ) and there distinctly apprehended , or judged of . so that the divers motions imprest upon the slender threads of any nerve , are sufficient to the causation of divers perceptions ; or , that we may not eclipse his notion by the obscurity of our expression , that the impulse , or stroke given to the nerve , doth , by reason of the continuity of its parts , cause another motion , in all points answerable to the first received by the external organ , to be carried quite home to the throne of the mind , which instantly makes a respective judgment concerning the nature of the object , from whence that particular motion was derived . in a word , that only by the variety of strokes given to the external organ , thence to the filaments of the nerve annexed thereto , thence to the praesence chamber of the soul : we are informed of the particular qualities , and conditions of every sensible ; the variety of these sensory motions being dependent on the variety of qualities in the object , and the variety of judgments dependent on the variety of motions communicate . and for the sense of seeing , in special ; he conceives it to be made , not by the mediation of images , but of certain motions ( whereof the images are composed ) transmitted through the eye and optick nerve to the centrals of the brain : praesuming the visible image of an object to be only an exact representation of the motions thereby impressed upon the external sensorium ; and accordingly determining the reason of the minds actual discernment of the colour , situation , distance , magnitude , and figure of a visible , by the instruments of sight , to be this . ( ) the light desilient from the adspectable body , in a direct line , called by the masters of the opticks , the axe of vision , percusseth the diaphanous fluid medium , the aether , or most subtile substance ( by him assumed to extend in a continuate fluor through the universe , and so to maintain an absolute plenitude , and continuity of parts therein . ) ( ) the aether thus percussed by the illuminant , serving as a medium betwixt the object and the eye ; conveyeth the impression through the outward membranes and humors , destined to refraction , to the optick nerve most delicately expansed into the retina tunica , beyond the chrystalline . ( ) the motion thus imprest on the outward extreme of the optick nerve , runs along the body of it to the inward extreme , determined in the substance of the brain . ( ) the brain receiving the impression , immediately gives notice thereof to its noble tenent , the soul ; which by the quality of the stroke judgeth of the quality of the striker , or object . in some proportion like an exquisite musitian , who by the tone of the sound thereby created , doth judge what cord in a virginal was strook , what jack strook that string , and what force the jack was moved withall , whether great , mean , or small , slow or quick , equal or unequal , tense or lax , &c. this you 'l say , is a conceit of singular plausibility , invented by a wit transcendently acute , adorned with the elegant dress of most proper and significant termes , illustrate with apposite similes and praegnant examples , and disposed into a method most advantageous for persuasion ; and we should betray our selves into the censure of being exceedingly either stupid , or malicious , should we not say so too : but yet we dare not ( so sacred is the interest of truth ) allow it to be more then singularly plausible ; since those arguments , wherewith the sage the● ● . chap. of his treatise of bodies ) hath long since impugned it , are so exceedingly praeponderant , as to over-ballance it by more then many moments of reason ; nor could des cartes himself , were he now unglorified , satisfie for his non-retractation of this error ; after his examination of their validity , by any more hopeful excuse , then this ; that no other opinion could have been consistent to his cardinal scope of solving all the operations of sense by mechanick principles . now , of all these opinions recited , we can find , after mature and aequitable examination , none that seems , either grounded on so much reason , or attended with so few difficulties , or so sufficient to the verisimilous explanation of all the problems , concerning the manner of vision , as that of epicurus ; which stateth the reason of vision in the incursion of substantial images into the eye . we say first , grounded on so much reason . for , insomuch as it is indisputable , that in the act of vision there is a certain sigillation of the figure and colour of the object , made upon that part of the eye , wherein the perception is ; and this sigillation cannot be conceived to be effected otherwise then by an impression ; nor that impression be conceived to be made , but by way of incursion of the image , or type : it is a clear consequence , that to admit a sigillation without impression , and an impression without incursion of the image , is a manifest alogy , an open inconsistence . and upon this consideration is it , that we have judged epicurus to have shot nearest the white , in his position that vision is performed , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , per simula ▪ chrorum incursionem , sive incidentiam : which agellius ( lib. . cap. . ) descanting upon , saith expresly , epicurus affluere semper ex omnibus corporibus simulachra quaedam ipsorum , eaque sese in oculos inferre , atque ita fieri sensum videndi putat . secondly , encumbred with so few difficulties . for , of all that have been hitherto , either by alexander ( . de anima . ) macrobius ( . saturnal . . ) galen ( lib. . de consensu in platonicis , hippocraticisque decretis ) or any other author , whose leaves we have revolved , objected against it ; we find only two , that require a profound exercise of the intellect to their solution : and they are these . ( ) obvious it is even to sense , that every species visible is wholly in the whole space of the medium , and wholly in every part thereof ; since in what part soever of the medium , the eye shall be admoved , in a position convenient , it shall behold the whole object , represented by the species : and manifest it is , that to be total in the total space , and total in every part thereof , is an affection proper only to incorporeals ; therefore cannot vision be made by corporeal images incurrent into the eye . ( ) in the intermediate aer are coexistent the images of many , nay innumerable objects ; which seems impossible , unless those images are praesumed to be incorporeal : because many bodies cannot coexist in one and the same place , without reciprocal penetration of dimensions , ergo , &c. sect . ii. to dispel these clouds , that have so long eclipsed the splendor of epicurus assertion , of the incidence of images visible into the eye ( for we shall not here dispute , whether he intended the sigillation to be made in that convex speculum , the chrystalline humour ; or that concave one , the retina tunica ) and explicate the abstruse nature of vision : we ask leave to possess you with certain necessary propositions : we assume therefore , assumption the first . that the superfice of no visible is so exquisitely smooth , polite , or equal , as not to contain various inaequalities , i. e. protuberant and deprest parts , or certain ( monticuli and valleculae ) small risings and fallings : which in some bodies being either larger , or more , are discoverable by the naked intuition of the eye ; and in others , either smaller , or fewer , require the detection of the microscope . this is neither praecarious , nor conjectural : but warranted by reason , and autoptical demonstration . for , if the object assumed be polisht marble ; since that apparent tersness in the surface thereof is introduced by the detrition of its grosser inaequalities by sand , and that sand is nothing but a multitude of polyedrical solid grains , by the acuteness and hardness of their angles cutting and derasing the more friable particles of the marble : it must follow , that each of the grains of sand must leave an impression of its edge , and so that the whole superfice must become scarified by innumerable small incisions , variously decussating and intersecting each other . if steel of a speculary smoothness , such as our common chalybeat mirrours ; since the tersness thereof is artificial , caused by the affriction of files , which cut only by the acuteness of their teeth , or lineal inaequalities : it is not easie to admit , that they leave no scratches , or exarations on the surface thereof ; and where are many incisions , each whereof must in latitude respond to the thickness of the tooth in the file , that made it , there also must be as many eminences or small ridges intercepted among them . and if glass ▪ whose smoothness seems superlative ; since it is composed of sand and salts , not so perfectly dissolved by liquation , as not to retain various angles : it cannot be unreasonable to inferr , that those remaining points or angular parts must render the composition in its exteriors full of asperities . and , as for autoptical evidence ; that marble , steel , and glass are unequal in their superfice , is undeniable not only from hence , that a good engyscope , in a convenient light , doth discover innumerable rugosities and cavities in the most polisht superfice of either : but also from hence , that spiders and flyes do ordinarily run up and down perpendicularly on venice glass , which they could not do , if there were not in the surface thereof many small cavities , or fastnings for the reception of the uncinulae , or hooks of their feet . to which may also be added , the humectation of glass by any liquor affused ; for , if there were no fosses and prominences in the superfice thereof , whereon the hamous particles of the liquid might be fastned , it would instantly run off without leaving the least of moisture behind . and hence assumption the second . that as the whole visible image doth emane from the whole superfice of the object ; so do all the parts thereof emane from all the parts of the object : i. e. that look how many atoms are designable in the superfice , from so many points thereof do atoms exhale , which being contiguously pursued by others and others successively deceding , make continued rayes , in direct lines tending thitherward , whither the faces of the particles point , from which they are deradiated . for , insomuch as in the superfice no particle can be so minute to the sense , as , in respect to the asperity , or inaequality of its surface , not to have various faces , by which to respect various parts of the medium : it must inevitably follow , that all the rayes effluxed from an object , do not tend one and the same way , but are variously trajected through the medium , some upward , others downward , some to the right , others to the left , some obversly or toward , others aversly or fromward , &c. so that there is no region or point of the compass designable , to which some rayes are not direct . and from this branch shoots forth our third assumption . that every visible image is then most dense and united , when it is first abduced from the object : or , that by how much the neerer the visible species is to the body , from which it is delibrated , by so much the more dense and united are the rayes of which it doth consist ; and so much the more rare or disgregate , by how much the farther it is removed from it . this may be exemplified in lines drawn from the centre of a circle to the circumference ; for by how much the farther they run from the centre , by so much the greater space is intercepted betwixt them : and by how much the larger space is intercepted betwixt them , by so much the greater must their rarity be , the degrees of rarity being determinable by the degrees of intercepted space . thus also must the rayes of the visible image , in their progress mutually recede each from other , and according to the more or less of their elongation from the point of abduction , become more or less rare and scattered , into the amplitude of the medium . however , we deny not the necessity of their innumerable decussations , and intersections ; in respect to the various faces , and confrontings of the parts of the superfice , from which they are emitted . and hence we extracted our fourth assumption . that the visible image , though really diffused through the space of the medium within the sphear of projection ; is notwithstanding neither total in the total space , nor total in every part thereof , as is supposed in the first objection : but so manifold , as there are parts of the medium , from which the object is adspectable . here may we introduce a paradox , which yet doth not want a considerable proportion of verisimilitude to justifie the sobriety and acuteness of his wit , that first started it ; which is , that of divers men , at the same time , speculating the same object , no one doth behold the same parts thereof , that are beheld by another : nay more , that no man can see the same parts of an object , with both eyes at once ; nay more , not the same parts with the same eye , if he remove it never so little , because the level of the visive axe is varied . this may be verified by a single reflection on the cause hereof , which is the inequality , or asperity of the superfice of bodies , seemingly most polite : for , in respect of that , it is of necessity , that various rayes , proceeding from the various parts thereof , variously convene in the parts of the medium ; and insomuch as each of those rayes doth represent that particle only , from which it was effused , and no other , in their concurse they cannot but represent other and other parts , according to the respective places or regions of the medium , in which the eye is posited , that receives them . however , we shall familiarize it by example . let two men at once behold a third , one before , the other behind : and both may be said to behold the same man , but , truly , not the same parts of him ; because the eyes of one are obverted to his anterior , and those of the other to his posterior parts . take it yet one note higher . let the face of a man be the object , on which though divers persons gaze at the same time , one on the right a second on the left side , a third confrontingly , a fourth and a fifth obliquely betwixt the other three ; and all may be said to have an equal prospect of the face : yet can it not be asserted , that they do all see the same parts thereof , but each a particular part . whence it may be inferred , that albeit we may allow them all to behold his fore-head , eyes , nose , cheeks , mouth , &c. yet can we not allow them all to see the same parts of forehead , eyes , nose , cheeks , &c. because of their unequal situation , which causeth that the whole species prodient from the face , doth not tend into the whole medium , but into various parts of it , respective to the various faces of the deradiant parts . moreover , because this praesumed inaequality is not competent only to the greater parts of the face , such as the eyes , nose , mouth , chin , &c. but as justly considerable in the very skin , which hath no designable place , wherein are not many smaller and smaller eminencies and depressions , deprehensible ( if not by the opticks of the body , yet ) by the ac●es of the mind : hence is , that having imagined the eyes of the five spectators to move their visive axes from part to part successively , and as slowly as the shadow of the gnomon steals over the parts of a dial , untill they have ranged over the whole face ; we may comprehend the necessity , of the discovery of a fresh part by every new aime or levell of each eye , and the baulking of others ; as if in particles of devex figure , no particels can be detected a new , but as many of those formerly discerned must be lost , and as many , nay more remain concealed . and this consideration smoothly ushers in two consectaries ( ) that to say , one simple species doth replenish the whole medium , is not , in the strict dialect of reason , so proper , as to say , the medium is possessed by an aggeries , or convention of innumerable species : which being divers in respect to the divers parts of the object , from which they were deradiated , must also be divers in their existence , and diffusion through the several parts of the perspicuum . and yet must they be allowed to constitute but one entire species ; and this in respect to their emanation from one object : because as the single parts of the species represent the single parts of the object , so doth the whole of the species represent the whole of the object . ( ) that many , nay myriads of different species may be coexistent in the common medium , the aer ; and yet no necessity of the coexistence of many bodies in one and the same place ; it being as justifiable to affirm , that they reciprocally penetrate each others dimensions , as that the warp and woof , or intersecting threads in a cloth , do mutually penetrate each other : because the aer is variously interspersed with inanities , or small empty roads , convenient to the inconfused transmission of all those swarms of rayes , of which the species consist . have you not frequently observed , when many candles were burning together in the same room , how , according to the various interposition of opace bodies , various degrees of shadows and light have been diffused into the several quarters of the same ? and can you give any better reason of those various intersections and decussations of the several lights , then this ; that the rayes of light streaming from the diverse flames , are directly and inconfusedly trajected through the several inane receptaries of the aer , respective to the position of each candle , without reciprocal impediment ; the rayes of one , that are projected to the right hand , in no wise impeding the passage of those of another , that are projected to the left , in the same sensible part of the aer . exactly so do the rayes of divers species visible , in their progress through the aer , pass on in direct and uninterrupted lines , without confusion : and though they may seem to possess the same sensible part of the medium , yet will not reason allow them to possess the same insensible particles thereof ; in regard the distinct transmission of each clearly demonstrateth , that each possesseth a distinct place . nor doth this their iuxta-position , or extreme nearness necessitate their confusion ; since we daily observe that water and wine may be so commixt in a vial , as therein can be assigned no sensible part , wherein are not some parts of both liquors : and yet most certain it is , that the particles of wine possess not the same invisible loculaments , or receptaries , that are replete with the particles of water , but others absolutely distinct ; because otherwise there would be as much of water , or wine alone , in the vial , as there is of both water and wine , which in that continent is impossible . and hereupon we conclude , that to admit every distinct species to replenish the whole medium ; is no less dangerous , then to admit , that each of two liquors confused doth singly replenish the whole capacity or the continent : the parity of reasons justifying the parallelism . assumption the fifth . that the visible image , being trajected through the pupil , and having suffered its ultimate refraction in that convex mirror , the chrystalline humor ; is received and determined in that principal seat of vision , ( which holds no remote analogy to a concave mirror ) the retina tunica , or expansion of the optick nerve in the bottom of the eye : and therein represents the object from whence it was deradiated , in all particulars to the life , i. e. with the same colour , figure , and situation of parts , which it really beareth ; provided the distance be not excessive . the first part of this eminent proposition , that excellent mathematician , christopher scheinerus , hath so evicted by physical reasons , optical demonstrations , and singular experiments ; as no truth can seem capable of greater illustration , and less opposition : and therefore the greatest right we can do our selves , or you , in this point , is to remit you to the observant lecture of his whole third book , de fundament . opticis ; which we dare commend with this just elogie , that it is the most elaborate and satisfying investigation of the principal seat of vision , that ever the world was enriched with , and he who shall desire a more accomplisht discourse on that ( formerly ) abstruse theorem , must encounter the censure of being either scarce ingenious enough to comprehend , or scarce ingenuous enough to acknowledge the convincing energy of the arguments and demonstrations therein alledged , for the confirmation of his thesis , radij formalitèr visorij nativam sedem esse tunicam retinam . and the other is sufficiently evincible even from hence ; that the sight , or ( if you please ) the interior faculty doth alwayes judge of t●e adspectable form of an object , according to the condition of the image emanant from it , at least , according as it is represented by the image , at the impression thereof on the principal visory part . which is a position of eminent certitude . for , no other cause can be assigned , why the visive faculty doth deprehend and pronounce an object to be of this , or that particular colour : but only this , that the image imprest on the net-work coat doth represent it in that particular colour , and no other . why , when half of the object is eclipsed , by some opace body interposed , the eye can speculate , nor the faculty judge of no more then the unobscured half : but only this , that the image is mutilated , and so consisteth of onely those radii , that are emitted from the unobscured half , and consequently can inferr the similitude of no more . why an object , of whatever colour , appeareth red , when speculated through glass of that tincture : but only because the image , in its trajection through that medium , being infected with redness , retains the same even to its sigillation on the expansion of the optick nerve . why the sight , in some cases , especially in that of immoderate distance , and when the object is beheld through a reversing glass , deprehends the object under a false figure : but because the image represents it under that dissimilar figure , having either its angles ●etused , by reason of a too long trajection through the medium , or the situation of its parts inverted , by decussation of its rayes in the glass . consectary the first . now , it being no less evident , then certain , that the image is the sole cause of the objects apparence under such or such a determinate colour , and of this or that determinate figure : it is of pure consequence , that the image must also be the cause of the objects appearance in this or that determinate magnitude ; especially since figure is essenced in the termination of magnitude , according to euclid . ( lib. . def . . ) figura est , quae sub aliquo , vel aliquibus terminis comprehenditur . for , why doth the object appear to be of great , small , or mean dimensions ; if not because the image arriving at the sentient , is great , small , or mean ? why doth the whole object appear greater then a part of it self ; unless because the whole image is greater then a part of it self ? to speak more profoundly , and as men not altogether ignorant of the mysteries in opticks ; demonstrable it is , that the magnitude of a thing speculated may be commensurated by the proportion of the image deradiated from it , to the distance of the common intersection . for as the diametre of the image , projected through a perspective , or astronomical tube , on a sheet of white paper , is in proportion to the axis of the pyramid eversed ; so is the diameter of the basis of the object to the axis of the pyramid direct . and hereby also come we to apprehend the distance of the object from the eye ; for having obtained the latitude of the object , we cannot want the knowledge of its distance : and by conversion , the knowledge of its distance both assists and facilitates the comprehension of its magnitude . which comes not much short of absolute necessity ; since as des cartes ( dioptrices cap. . ) hath excellently observed , in these words : quoniam autem longitudo longius decurrentiam radiorum non exquisite salis ex modo impulsus cognosci potest , praecedens distantiae scientia hic in auxilium est vocanda . sic , ex gr. s● distantia cognoscatur esse magna , & angulus visionis sit parvus ; res objecta longius distans judicatur magna : sin verò distantia sciatur esse parva , & angulus visionis sit magnus ; objectum judicatur esse parvum , si verò distantia objecti longius dissiti sit in cognita ; nihilcerti de ejus magnitudine decerni potest : if the distance of an object far removed be unknown , the judgment concerning the magnitude thereof must be uncertain . consectary the second . again , insomuch as the receptary of the visible image , is that concave mirrour , the retina tunica ( we call it a concave mirrour , not only in respect of its figure and use , but also in imitation of that grand master of the opticks , alhazen , who ( in lib. . cap. . ) saith thus ; et sequitur ex hoc , at corpus sentiens , quod est in concavo nervi ( retina nimirum ) sit aliquantulùm diaphanum , ut appareant in eo formae lucis & coloris , &c. ) hence is it , that no image can totally fill that receptary , unless it be derived from an object of an almost hemispherical ambite , or compass ; so that the rayes , tending from it to the eye , may bear the form of a cone , whose base is the hemisphere , and point ( somewhat retused ) the superfice of the pupil . this perfectly accords to keplers canon ; visionem fieri , cum totius hemispherij mundani , quod est ante oculum , & amplius paulo , idolum statuitur ad album subrufum retinae cavae superficiei parietem . ( in paralipomen . ad vitellion . cap. . de modo vision . num . . ) not that either he , or we , by the optical hemisphere , intend only the arch of the firmament ; but any ambite whatever , including a variety of things obverted to the open eye , partly directly , partly obliquely , or laterally , and circumquaque in all points about . and this being conceded , we need not long hunt for a reason , why , when the eye is open , there alwayes is pourtraied in the bottom of the eye some one total image ; whose various parts may be called the special images of the diverse things at once objected . for , as the whole hemisphere visive includes the reason of the whole visible : so do the parts thereof include the reason of the special visibles , though situate at unequal distance . and , since , the hemisphere may be , in respect either of its whole , or parts , more remote , and more vicine ; hence comes it , that no more rayes arrive at the eye from the remote , than the vicine : because in the vicine , indeed , are less or fewer bodies , than in the remote , but yet the particles , or faces of the particles of bodies , that are directly obverted to the pupil , are more . which certainly is the cause , why of two bodies , the one great , the other small , the dimensions seem equal ; provided the great be so remote , as to take up no greater a part of the visive hemisphere , than the small : because , in that case , the rayes emanant from it , and in direct lines incident into the pupill of the eye , are no more then those deradiate from the small , and consequently cannot represent more parts thereof , or exhibit it in larger dimensions . whereupon we may conclude that the visive faculty doth judge of the magnitude of objects , by the proportion that the image of each holds to the amplitude of the concave of the retina tunica : or , that by how much every special image shall make a greater part of the general image , that fills the whole hemisphere visive , and so possess a greater part of the concave of the retina tunica ; by so much the greater doth the faculty judge the quantity thereof to be : and ● contra. and , because a thing , when near , doth possess a greater part of the visive hemisphere , than when remote : therefore doth the special image thereof also possess a greater part of the concave in the retina tunica , and so exhibit in greater dimensions ; and it decreaseth , or becometh so much the less , by how much the farther it is abduced from the eye ; for it then makes room for another image of another thing , that is detected by the abduction of the former , and enters the space of the hemisphere obverted . and hereupon may we ground a paradox . that the eye sees no more at one prospect then at another : or , that the eye beholds as much when it looks on a shilling , or any other object of as small diameter , as when it speculates a mountain , nay the whole heaven . which though obscure and despicable at first planting , will yet require no more time to grow up to a firm and spreading truth , than while we investigate the reasons of two cozen-german optical phaenomena's . ( ) why an object appears not only greater in dimensions , but more distinct in parts , when lookt upon near at hand ; than afarr off ? ( ) why an object , speculated through a convex glass , appears both larger and more distinct ; than when beheld only with eye : but through a concave , both smaller , and more confused ? to the solution of the first , we are to reflect on some of the praecedent assumptions . for , since every visible diffuseth rayes from all points of it superfice , into all regions of the medium , according to the second assumption ; and since the superfice of the most seemingly smooth and polite body , is variously interspersed with asperities , from the various faces whereof , innumerable rayes are emitted , tending according their lines of direction , into all points of medium circularly ; according to the first assumption ; and since those swarms of emanations must be ●o much the more dense and congregate , by how much the less they are elongated from their fountain , or body exhalant ; and è contra , so much the more rare and disgregate , by how much farther they are deduced , according to the third assumption : therefore , by how much nearer the eye shall be to the object by so much a greater number of rayes shall it receive from the various parts thereof , and the particles of those parts ; and è contra : and consequently by how much a greater number of rayes are received into the pupill of the eye , by so much greater do the dimensions of the object , and so much the more distinct do the parts of it superfice appear . for it is axiomatical among the masters of the opticl●s , and most perfectly demonstrated by scheinerus ( in lib. . fundament . optic . part . . cap. . ) that the visive axe consisteth not of one single raye , but of many concurring in the point of the pyramid , terminated in the concave of the retina tunica : and as demonstrable , that those rayes only concurr in that conglomerated stream , which enters the pupil , that are emitted from the parts of the object directly obverted unto it ; all others ●ending into other quarters of the medium . and hence is it , that the image of a remote object , consisting of rayes ( which though streaming from distant parts of the superfice thereof , do yet , by reason of their concurse in the retused point of the visive pyramid , represent those parts as conjoyned ) thin and less united , comparatively ; those parts must appear as contiguou● in the visifical representation , or image , which are really incontiguous or seperate in the object : and upon consequence , the object must be apprehended as contracted , or less , as consisting of fewer parts ; and also confused , as consisting of parts not well distinguisht . this may be truly , though somewhat grosly , exemplified in our prospect of two or three hills situate at large distance from our eye , and all included in the same visive hemisphere ; for , their elongation from the eye makes them appear contiguous , nay one and the same hill , though perhaps they are , by more then single miles , distant each from other : or , when from a place of eminence we behold a spacious campania beneath , and apprehend it to be an intire plane ; the non-apparence of those innumerable interjacent fosses , pits , rivers , &c. deprest places , imposing upon the sense , and exhibiting it in a smooth continued plane . and to the solution of the second problem , a concise enquiry into the causes of the different effects of concave and convex perspicils , in the representation of images visible , is only necessary . a concave lens , whether plano-concave , or concave on both sides , whether it be the segment of a great , or small circle , projects the image of an object , on a paper set at convenient distance from the tube that holds it , confused and insincere ; because it refracts the rayes thereof even to disgregation , so that never uniting again , they are transmitted in divided streams and cause a chaos , or perpetual confusion . on the contrary , a convex lens refracts the rayes before divided , even to a concurse and union , and so makes that image distinct and ordinate , which at its incidence thereon was confused and inordinate . and so much the more perfect must every convex lens be , by how much greater the sphere is , of which it is a section . for , as kircher well observes ( in magia parastatica . ) if the lens be not only a portion of a great sphere , v. gr. such a one , whose diametre contains twenty or thirty roman palms ; but hath its own diametre consisting of one , or two palmes : it will represent objects of very large dimensions , with so admirable similitude , as to inform the visive faculty of all its colours , parts , and other discoverables in it superfice . of which sort are those excellent glasses , made by that famous artist , eustachio divini , at rome ; by the help whereof the painters of italy use to draw the most exquisite chorographical , topographical , and prosopographical tables , in the world. this difference betwixt concave and convex perspicils is thus stated by kircher ( art. magnae lucis & umbrae ▪ lib. . magiae part . . sect. . ) hinc patet differentia lentis conve●ae & concavae ; quod illa confusam speciem acceptam transmissamque semper distinguit , & optimè ordinat : ●lla verò eandem perpetuo confundit ; unde officium lentis convexae est , easdem confusè accept is , in debita distantia , secundum suam potentiam , distinguere & ordinare . and by scheinerus ( in fundam . optic . lib. . part . . cap. . ) thus ; licet in vitro quocunque refractio ad perpendicularem semper accidat , quia tamen ipsum superficie cava terminatur , radij in aerem egressi potius disperguntur , quàm colliguntur : cujus contrarium evenit vitro convexo , ob contrariam extremitatem . rationes sumuntur à refractionibus in diversa tendentibus , vitri convexi & concavi , ob contrarias extremitatum configurationes . concavitas enim radios semper magis divergit : sicut convexitas amplius colligit , &c. now , to draw these lines home to the centre of our problem ; since the rayes of a visible image trajected through a convex perspicil , are so refracted , as to concurr in the visive axe : it is a clear consequence , that therefore an object appears both larger in dimensions , and more distinct in parts , when speculated through a convex glass , than when lookt upon only with the eye ; because more of the rayes are , by reason of the convexity of its extreme obverted to the object , conducted into the pupil of the eye , than otherwise would have been . for , whereas some rayes proceeding from those points of the object , which make the centre of the base of the visive pyramid , according to the line of direction , incurr into the pupil ; others emanant from other parts circumvicine to those central ones , fall into the iris ; others from other parts circumvicine fall upon the eye-lids ; and others from others more remote , or nearer to the circumference of the base of the pyramid , strike upon the eyebrows , nose , forehead , and other parts of the face : the convexity of the glass causeth , that all those rayes , which otherwise would have been terminated on the iris , eye-lids , brows , nose , forehead , &c. are refracted , and by refraction deflected from the lines of direction , so that concurring in the visive axe , they enter the pupil of the eye in one united stream , and so render the image imprest on the retina tunica , more lively and distinct , and encreased by so many parts , as are the rayes superadded to those , which proceed from the parts directly confronting the pupil . on the contrary ; because an image trajected through a concave perspicill , hath its rayes so refracted , that they become more rare and disgregate : the object must therefore seem less in dimensions , and more confused in parts ; because many of those rayes , which according to direct tendency would have insinuated into the pupill , are diverted upon the iris , eyelids , and other circumvicine parts of the face . here opportunity enjoyns us to remember the duty of our profession , nor would charity dispense , should we , in this place , omit to prescribe some general directions for the melioration of sight , or natively , or accidentally imperfect . the most common diminutions of sight , and those that may best expect relief from dioptrical aphorisms , and the use of glasses ; are only two : presbytia , and myopia . the first , as the word imports , being most familiar to old men , is ( visus in perspiciendis object is propinquis obscuritas ; in remotis verò integrum acumen ) an imperfection of the sight , by reason whereof objects near hand appear obscure and confused , but at more distance , sufficiently clear and distinct . the cause hereof generally , is the defect of due convexity on the outside of the chrystalline humor ; arising either from an error of the conformative faculty in the contexture of the parts of the eye , or ( and that mostly ) from a consumption of part of the chrystalline humour by that marasmus , old age : which makes the common base of the image visible to be trajected so far inwards , as not to be determined precisely in the centre of the concave of the retina tunica . and therefore , according to the law of contrariety , the cure of this frequent symptome is chiefly , if not only to be hoped from the use of convex spectacles , which determine the point of concurse exactly in the centre of the retina tunica ; the rayes , by reason of the double convexity , viz. of the lens and chrystalline humor , being sooner and more vigorously united , in the due place . the other , being contrary to the first , and alwayes native , commonly named purblindness , physitians define to be obscuritus visus in cernendis rebus distantibus ; in propinquis verò integrum acumen : a dimness of the sight in the discernment of objects , unless they be appropinquate to the eye . the causes hereof generally are either the too spherical figure of the chrystalline humor ; or , in the ductus ciliares , or small filaments of the aranea tunica ( the proper investment of the chrystalline ) a certain ineptitude to that contraction , requisite to the adduction of the chrystalline inwards towards the retina tunica , which is necessary to the discernment of objects at distance : either of these causes making the common base of the image to be determined in the vitrious humor , and consequently the image to arrive at the retina tunica , perturbed and confused . and therefore our advice is to all purblind persons , that they use concave spectacles : for such prolong the point of concurse , untill it be convenient , i. e. to the concave of the retina tunica . assumption the sixth and last . since all objects speculated under the same angle , seem of equal magnitude ( according to that of scheinerus , sicut oculus rem per se parvam , magnam arbitratur , quia sub magno angulo , refractionis beneficio , illam apprehendit : & magnam contrario parvam ; fundament . optic . lib. . part . . cap. . ) and are accordingly judged , unless there intervene an opinion of their unequal distance , which makes the spectator praesume , that that object is in it self the greater , which is the more remote , and that the less , which is the less remote : therefore , to the appehension and dijudication of one of two objects , apparently equal , to be really the greater , is not required a greater image , than to the apprehension and dijudication of an object to be really the less ; but only an opinion of its greater distance . this may receive both illustration and confirmation from this easie experiment . having placed horizontally , in a valley , a plane looking glass , of no more then one foot diametre ; you may behold therein , at one intuition the images of the firmament , of the invironing hills , and all other things circumsituate , and those holding the same magnitude , as when speculated directly , and with the naked eye : and this only because , though the image in dimensions exceed not the area of the glass , yet is it such , as that together with the things seen , it doth also exhibit the distance of each from other . exactly like a good landskip , wherein the ingenious painter doth artificially delude the eye by a proportionate diminution and decurtation of the things praesented , insinuating an opinion of their distance . and therefore , the reason , why the images of many things , as of spacious fields , embroydered with rowes of trees , numerous herds of cattle , flocks of sheep , &c. may at once be received into that narrow window , the pupill of the eye , of a man standing on an hill , tower , or other eminent place , advantageous for prospect : is only this , that to the speculation of the hemisphere comprehending all those things , in that determinate magnitude , is required no greater an image , than to the speculation of an hemisphere , whose diametre is commensurable only by an inch . since neither more rayes are derived from the one to the pupil of the eye , than from the other : nor to the judication of the one to be so much greater than the other , is ought required , beside an opinion that one is so much more distant than the other . and this we conceive a sufficient demonstration of the verity of our last paradox , viz. that the eye sees as much , when it looks on a shilling , or other object of as small diametre ; as when it looks on the greatest ocean . here most opportunely occurs to our consideration that notorious problem , quomodo objecti distantia deprehendatur ab oculo ? how the distance of the object from the eye is perceived in the act of vision ? this would des cartes have solved ( ) by the various figuration of the eye . because in the conspection of objects remote , the pupil of the eye is expanded circularly , for the admission of more rayes ; and the chrystalline humor somewhat retracted toward the retina tunica , for the determination of the point of concurse in the same , which otherwise would be somewhat too remote : and on the contrary , in the conspection of objects vicine , the pupil is contracted circularly , and the chrystalline lens protruded somewhat outwardly , for the contrary respects . ( ) by the distinct , or confused representation of the object ; as also the fortitude , or imbecillity of light illustrating the same . because things represented confusedly , or illustrated with a weak light alwayes appear remote : and on the contrary , things praesented distinctly or illustrate with a strong light , seem vicine . but all this we conceive unsatisfactory . ( ) because , unless the variation of the figure of the eye were gradual , respective to the several degrees of distance intercedent betwixt it and the object ; it is impossible the sight should judge an object to be at this or that determinate remotion : and that the variation of the figure of the eye is not gradual respective to the degree of distance , is evident even from hence ; that the pupil of the eye is as much expanded , and the lens of the chrystalline humor as much retracted toward the retina tunica , in the conspection of an object situate at one miles distance , as of one at , , , or more miles ; there being a certain term of the expansion of the one part , and retraction of the other . ( ) because though vision be distinct , or confused , both according to the more or less illustration of the object by light , and to the greater or less distance thereof from the eye ; yet doth this reason hold only in mean , not large distance : since the orbs of the sun and moon appear greater at their rising immediately above the horizon , that is , when they are more remote from the eye , than when they are in the zenith of their gyre , that is , when they are more vicine to the eye ; and since all objects illustrate with a weak light , do not appear remote , nor ● contra , as common observation demonstrateth . and therefore allowing the acuteness of des cartes conceit , we think it more safe , because more reasonable to acquiesce in the judgment of the grave gassendus ; who ( in epist. . de apparente magnitud . solis humilis & sublimis ) most profoundly solves the problem , by desuming the cause of our apprehending the distance of an object , in the act of vision , from a comparison of the thing interjacent between the object seen , and the eye . for , though that comparation be an act of the superior faculty ; yet is the connexion thereof to the sense , necessary to the making a right judgment , concerning the distance of the visible . and , most certainly , therefore do two things at distance seem to be continued , because they strike the eye with cohaerent , or contiguous rayes . thus doth the top of a tower , though situate some miles beyond a hill , yet seem contiguous to the same , nay to the visible horizon ; and this only because it is speculated by the mediation of contiguous rayes : and the sun and moon , both orient and occident , seem to cohaere to the horizon because though the spaces are immense , that intercede betwixt their orbs and the horizon , yet from those spaces doth not so much as one single raye arrive at the eye , and those which come to it from the sun and moon are contiguous to those which come from the horizon . and hence is it , that the tower , hill , and horizon seem to the sight to be equidistant from the eye ; because no other things are interposed , at least , seen interposed , by the comparison of which , the one may be deprehended more than the other . besides , the distance of the horizon it self is not apprehended by any other reason , but the diversity of things interjacent betwixt it and the eye : for , look how much of space is possessed valleys and lower grounds interjacent , so much of space is defalcated from the distance ; the sight apprehending all those things to be contiguous , or continued , whose rayes are received into the eye , as contiguous , or continued , none of the spaces interjacent affording one raye . of which truth des cartes seems to have had a glimpse , when ( in dioptrices cap. . sect. . ) he conceds ; objectorum , quae intuemur , praecedaneam cognitionem , ipsorum distantiae melius dignoscendae inservire : that a certain praecognition of the object doth much conduce to the more certain dignotion of its distance . and on this branch may we ingraft a paradox ; that one and the same object , speculated by the same man , in the same degree of light , doth alwayes appear greater to one eye , than to the other . the truth of this is evincible by the joint testimony of those incorruptible witnesses of certitude , experience and reason . ( ) of experience , because no man can make the vision of both his eyes equally perfect ; but beholding a thing first with one eye , the other being closed , or eclipsed , and then with the other , the former being closed or eclipsed ; shall constantly discover it to be greater in dimensions in the apprehension of one eye , than of the other : and gassendus , making a perfect and strict experiment hereof , testifies of himself , ( in epist. . de apparent . magnitud . solis , &c. sect. . ) that the characters of his book appeared to his right eye , by a fifth part , greater in dimensions , though somewhat more obscure , than to his left . ( ) of reason ; because of all twin parts in the body , as ears , hands , leggs , testicles , &c. one is alwayes more vigorous and perfect , in the performance of its action , than the other . which inaequality of vigour , if it be not the bastard of custom , may rightfully be fathered upon either this ; that one part is invigorated with a more liberal afflux of spirits , than the other : or this , that the orgaganical constitution of one part is more perfect and firm , than that of the other . and , therefore , one eye having its pupill wider ; or the figure of the chrystalline more convex , or the retina tunica more concave , than the other ; must apprehend an object to be either larger in dimensions , or more distinct in parts , than the other , whose parts are of a different configuration : either of these causes necessitating a respective disparity in the action . if this sound strange in the ears of any man , how will he startle at the mention of that much more paradoxical thesis of ioh. baptista porta ( lib. . de refra●tion . cap. . ) that no man can see ( distinctly ) but with one eye at once ? which though seemingly repugnant not only to common persuasion , but also to that high and mighty axiom of alhazen , vitellio , franc. bacon . niceron , and other the most eminent professors of the optiques , that the visive axes of both eyes concurr and unite in the object speculated : is yet a verity , well worthy our admission , and assertion . for , the axes of the eyes are so ordained by nature , that when one is intended , the other is relaxed , when one is imployed , the other is idle and unconcerned ; nor can they be both intended at once , or imployed , though both may be at once relaxed , or unimployed : as is experimented , when with both eyes open we look on the leaf of a book ; for we then perceive the lines and print thereof , but do not distinctly discern the characters , so as to read one word , till we fix the axe of one eye thereon ; and at that instant we feel a certain suddain subsultation , or gentle impulse in the centre of that eye , arising doubtless from the rushing in of more spirits through the optick nerve , for the more efficacious performance of its action . the cause of the impossibility of the intention of both visive axes at one object , may be desumed from the parallelism of the motion of the eyes ; which being most evident to sense , gives us just ground to admire , how so many subtle mathematicians , and exquisite oculists have not discovered the coition and union of the visive axes in the object speculated , which they so confidently build upon , to be an absolute impossibility . for , though man hath two eyes ; yet doth he use but one at once , in the case of distinct inspection , the right eye to discern objects on the right side , and the left to view objects on the left : nor is there more necessity , why he should use both eyes at once , than both arms , or leggs , or testicles , at once . and for an experiment to assist this reason ; we shall desire you only to look at the top of your own nose , and you shall soon be convicted , that you cannot discern it with both eyes at once ; but the right side with the right eye , and afterward the left side with the left eye : and at the instant of changing the axe of the first eye , you shall be sensible of that impulse of spirits , newly mentioned . no● , indeed , is it possible , that while your right eye is levelled at the right side of your nose , your left should be levelled at the left side , but on the contrary averted quite ●rom it : because , the motion of the eyes being conjugate , or parallel , when the axe of the right eye is converted to the right side of the nose , the axe of the left must be converted toward the left ear. and , therefore , since the visive axes of both eyes cannot concurr and unite in the tipp of the nose ; what can remain to persuade , that they must concurr and unite in the same letter , or word in a book , which is not many inches more remote than the nose ? and , that you may satisfie your self , that the visive axes doe never meet , but run on in a perpetual parallelism , i. e. in direct lines , as far distant each from other , as are the eyes themselves ; having fixed a staff or launce upright in the ground , and retreated from it to the distance of or paces , more or less : look as earnestly as you can , on it , with your right eye , closing your left , and you shall perceive it to eclipse a certain part of the wall , tree , or other body situate beyond it . then look on it again with your left eye , closing your right ; and you shall observe it to eclipse another part of the wall : that space being intercepted , which is called the parallaxe . this done , look on it with both eyes open ; and if the axes of both did meet and unite in the staff , as is generally supposed , then of necessity would you observe the staff to eclipse either both parts of the wall together , or the middle of the parallaxe : but you shall observe it to do neither , for the middle shall never be eclipsed ; but only one of the parts , and that on which you shall fix one of your eyes more intently than the other . this considered , we dare second gassendus in his promise to gunners , that they shall shoot as right with both eyes open , as only with one : for levelling the mouth of the peece directly at the mark , with one eye , their other must be wholly unconcerned therein , nor is it ought but the tyrannie of custome , that can make it difficult . here , to prevent the most formidable exception , that lyes against this paradox , we are to advertise you of two considerables . first , that as well philosophers , as oculists unanimously admit three degrees , or gradual differences of sight . ( ) visus perfectissimus , when we see the smallest ( visible ) particles of an object , most distinctly : ( ) perfectus , when we see an object distinctly enough , in the whole or parts , but apprehend not the particles , or minima visibilia thereof : ( ) imperfectus , when besides the object directly obverted to the pupil of the eye , we also have a glimmering and imperfect perception of other things placed ad latera , on the right and left side of it . secondly , that the verity of this paradox , that we see but with one eye at once , is restrained only to the first and second degrees of sight , and extends not to the last . for , experience assures , that , as many things circumvicine to the principal object , on which we look only with one eye open , praesent themselves together with it , in a confused and obscure manner : so likewise , when both eyes are open , many things , obliquely incident into each eye , are confusedly , and indistinctly apprehended . so that in confused and imperfect vision , it may be truly said , that a man doth see with both eyes at once : but not in distinct and perfect . sect . iii. to entertain curiosity with a second course , we shall here attempt the conjectural solution of those so much admired effects of convex and concave glasses ; that is , why the rayes of light , and together with them those substantial effluxes , that essence the visible images of objects , being trajected through a convex glass , or reflected from a concave , are congregated into a perpendicular stream : and likewise , why the rayes of light , being trajected through a concave , or reflexed from a convex , are disgregated from a perpendicular radius . first , insomuch as glass , of the most polite and equal superfice is full of insensible pores , or perforations , and solid impervious granules , alternately interspersed ; we may upon consequence conceive , that each of those solid granules is as it were a certain monticle , or small hillock , having a small top , and small sides circularly declining toward those little valleys , the pores . this conceded ▪ if a glass , whose superfice is plane , be obverted to the sun , since the small pores thereof tend from one superfice to the other in direct and parallel lines , for the most part ; it must be , that all the rayes incident into the pores , pass through in direct and parallel lines , into the aer beyond it : and so can be neither congregated , nor disgregated , but must constantly pursue the same direct course , which they continued from the body of the sun , to their incidence on the surface of the glass . but if the extream of the glass , respecting the sun , be of a convex figure ; then , because one pore ( conceive it to be the central one ) is directly obverted to the sun , and all the others have their apertures more oblique and , pointing another way ; therefore it comes to pass , that one ray , falling into the directly obverted pore , is directly trajected through the same , and passeth on into the aer beyond it in a direct line ; but another ray , falling on the side of the hillock next adjacent to the right pore , is thereby refracted and deflected , so that it progresseth not forward in a line parallel to the directly trajected ray , but being conjoined to it , passeth on in an united stream with it . and necessary it is , that the angle of its refraction be by so much the more obtuse , by how much nearer the point of the hillock , from which it was refracted , is to the direct or perpendicularly transmitted ray ; and , on the contrary , by so much the more acute , by how much the more remote : because there the ray falls more deeply into the obvious pore , and strikes lower on the adjacent hillock , whose protuberancy therefore doth less deflect it ; but here the ray falls higher on the side of the hillock , and so by the protuberancie , or devexity thereof is more deflected . but if the extreme of the glass confronting the sun , be of a concave figure ; in that case , because one pore being directly open , others have their apertures more obliquely respecting the sun , it comes to pass , that the ray falling into the direct pore , is directly trajected , and passeth through the aer in a perpendicular ; but another ray falling on the side of the next adjacent hillock , is thereby refracted and deflected , so that it doth not continue its progress in a line parallel to the directly-transient ray , but is abduced from it , and that so much the more , by how much the farther it passeth beyond the glass . and necessary it is , that the angle of its refraction be also so much the more obtuse , by how much nearer the point of its incidence on the side of the hillock , is to the aperture of the direct pore ; because it falls deeper into it , and strikes lower on the devex side of the hillock : and on the contrary , so much the more acute , by how much more remote its point of incidence is to the aperture of the direct pore ; for the contrary respect . and this is the summ of our conjecture , touching the reasons of the different trajection of rayes through convex and concave glasses . as for the other part of our conception , concerning reflexed rayes ; if the glass obverted to the sun be plane in it superfice , then , because all the topps of the solid and impervious hillocks , are directly obverted to the sun , therefore must it be , that all the rayes incident upon them become reflected back again toward the sun , if not in the same , yet at least in contiguous lines . but if the face of the glass obverted to the sun , be convex ; then , because the topp of one hillock is directly obverted , and those of others obliquely respecting the sun ; it comes to pass , that one ray being directly reflected , the others are reflected obliquely in lines quite different : and this in an angle by so much more acute , by how much nearer the topps of the obliquely respecting hillocks are to that of the directly respecting one ; and by so much the more obtuse , by how much the more remote . and , if the side of the glass turned toward the sun , be concave ; because the top , of one hillock is directly , and those of others obliquely obverted to the sun ; hence comes it , that the ray incident on the directly-obverted one , is directly reflected , and those that fall on the topps of the obliquely-obverted ones , are accordingly reflected obliquely , toward the directly reflected ; so that at a certain distance they all concurr and unite with it in that point , called the term of concurse : and this in an angle so much more acute , by how much nearer the topps of the obliquely-reflecting hillocks are to that of the directly-reflecting one ; and è contra . these things clearly understood , we need not want a perfect demonstration of the causes , why a concave glass , whose concavity consisteth of the segment of an ellipsis , reflecteth the rayes of the sun in a more acute angle , and consequently burneth both more vigorously , and at greater distance , then one whose concavity is the segment of a parabola : and why a parabolical section reflecteth them in an angle more acute , and so burneth both at greater distance , and more vigorously , than the section of circle . especally if we familiarize this theory by the accommodation of these figures . thus have we , in a short discourse , not exceeding the narrow limits of a single article , intelligibly explicated the cause of that so much admired disparity in the effects of plane , convex , and concave , glasses ; as well dioptrical , or trajecting the rayes of light into the aer beyond them , as catoptrical , or reflecting them back again from their obverted superfice . and we ask leave to encrease our digression only with this consectary . because the rayes of light , and the rayes of visible images are analogical in their nature , and flow hand in hand together into the eye , in the act of vision ; therefore is it , that to a man using a plane perspicil , an object alwayes appears the same , i. e. equal in dimensions , and distinction of parts , as it doth to his naked eye : by reason the angle of its extreams is the same in the plane glass , as in the eye . but , to a man using a convex perspicil , an object appears greater ; because the angle of its extreams is ampli●ied : and through a concave , less ; because the angle is diminished . in like manner , the image of an object reflected from a plane mirrour , appears the same to the spectator , as if deradiated immediately , or without reflexion , from the object it self ; because the reflex angle is equal to the direct : but the image of an object reflected from a convex mirrour appears less ; because the angle of its reflection is less than that of its direction : and from a concave , greater ; because the reflex angle is greater than the direct : this may be autoptically demonstrated thus . if you admit the image of a man , or any thing else , through a small perforation of the wall , into an obscure chamber , and fix a convex lens in the perforation , with the convex side toward the light ; you shall , admoving your eye thereto , at convenient distance , observe the transmitted image to be amplified : but , receiving the image on a sheet of white paper , posited where your eye was , you shall perceive it to be minorated : the contrary effect arising from a concave lens , posited in the hole , with its concave side toward the light. and this , because the convex congregating the rayes into the pupill of the eye ( and so making the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or apparition greater , for the cause formerly exposited ) doth also congregate them on the paper ; and therefore the image cannot appear contracted , or minorated : but on the contrary , the concave disgregating the rayes from the pupil ( and so making the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or apparition less in the retina of the optick nerve ) doth also disgregate , or diffuse them largely on all parts of the paper , and so the image thereon received cannot but appear much amplified . sect . iv. hitherto we have in some degree of satisfaction , explicated the manner , how , by the incursion of substantial images , dera●●ated from the object to the eye , the visive faculty comes to apprehend the colour , figure , magnitude , number , and distance of objects : and therefore it remains only , to the complement of our present designation , that we explore the reasons of the perception of the situation , quiet , and motion of objects , by the sight . to our more perspicuous solution of which notable difficulty ; and to the illustration of many passages precedent in the two last sections : it must be confest not only ornamental , or advantageous , but simply necessary , that we here anatomize the whole eye , and consider the proper uses of the several parts thereof ; those especially , that are either immediately and primarily instrumental , or only secundarily inservient to vision . but , because the axe of the visive pyramid is a perpendicular line , beginning in the extrems of the object , and ending in the amphiblestroides ; had the eye been nailed or fixt in its orbita , we must have been necessitated to traverse the whole machine of the body , for a position thereof convenient to vision , since it can distinctly apprehend no object , but what lyes è directo opposite ; or have had this semi-rational sense , whose glory builds on variety , restrained to the speculation of so few things , that we should have received more discomfort from their paucity , than either information , or delight from their discernment : therefore , that we might enjoy a more enlarged prospect , and read the whole hemisphere over in one momentany act of vision , nature hath furnished the eyes with muscles , or organs of agility ; that so they may accommodate themselves to every visible , and hold a voluntary verlisity to the intended object ; par●●ula sic magnum pervisit pupula coelum . and of these ocular muscles there are in man , just so many , as there are kinds of motion , direct , and oblique or circular ; all situate within the orbita , and associated to the optick nerve , and conjoining their tendons , at the horny membrane , they constitute the tunica innomitata , so named by columbus , who arrogates the invention thereof to himself , though galen ( lib. . de usu part . cap. . ) makes express mention of it . the first of the four direct muscles , implanted in the superiour part of the eye , draweth it upward ; whence it is denominated atollens , the lifter up , and superbus , the proud : because this is that we use in haughty and sublime looks . the second , situate in the inferiour part of the eye , and antagonist to the former , stoops the eye downward ; and thence is called deprimens the depressor , and humilis , the humble : for this position of the eye speaks the dejection , and humility of the mind . the third , fastned in the major canthus , or great angle of the eye , and converting it toward the nose ; is therefore named adducens the adducent , and bibitorius , for in large draughts we frequently contract it . the fourth , opposite both in situation and office to the former , abduceth the eye laterally toward the ear ; and is therefore named abducens , and indignatorius , the scorning muscle : for , when we would cast a glance of scorn , contempt , or indignation , we contract the eye towards the outward angle , by the help of this muscle . if all these four work together , the eye is retracted inward , fixt , and immote : which kind of motion physitians call motus tonicus , and in our language , the sett , or wist look . of the ●bl●que muscles , the first , running betwixt the eye , and the tendons of the second and third muscles , by the outward angle ascends to the superior part of the eye , and inserted near to the rainbow , circumgyrates the eye downward . the second , and smallest , twisted into a long tendon , circumrotates the eye toward the interior angle , and is called the trochlea , or pully . these two circumactors are sirnamed amatorij , the lovers muscles ; for these are they that roul about the eye in wanton or amorous glances . and thus much of the conformation of the eye . now , as to the solution of our problem , viz. how the situation of an object is perceived by the sight ? since it is an indisputable canon , omnem sensum deprehendere rem ad eam regionem , è qua ultimò directa metione feritur , that every sense doth apprehend its proper object to be situate in that part of space , from whence , by direct motion , it was thereby affected : we may safely inferr , that the visible object alwayes appears situate in that part of space , from whence the image thereof in a direct line invadeth the eye , and enters the pupil thereof . which is true and manifest not only in the intuition of an object by immediate or direct rayes ; but also in the inspection of looking-glasses , that represent the object by reflex : and a pure consequence , that a visible object , by impression of its rayes proceeding from a certain place , or region , must of necessity be perceived by the sight , in its genuine position , or erect form ; though we have the testimony both of reason and autopsie , that the image of every visible is pourtraid in the amphiblestroides , in an unnatural position , or everse form. and , as for that of autopsie , or ocular experiment ; take the eye of an oxe , or ( if the anatomick theatre be open ) of a man , for in that the species are represented more to the life , than in the eye of any other animal , as des cartes ( in dioptrices cap. . sect. . ) and having gently stript off the three coats in the bottome , in that part directly behind the chrystalline , so that the pellucidity thereof become visible , place it in a hole of proportionate magnitude , in the wall of your closet , made obscure by excluding all other light , so that the anterior part theaeof may respect the light . this done , admoving your eye towards the denudated part of the chrystalline ; you may behold the species of any thing obverted to the outside of the eye , to enter through the chrystalline to the bottom thereof , and there represented in a most lively figure , as if pourtrayed by the exquisite pencil of apelles ; but who●ly eversed : as in this following iconisme . finally , an object appears either in motion , or quiet , according as the image thereof , represented on the retina tunica , is moved : or quiet : only because , according to the canon , in the praecedent article , touching the reason of the perception of the situation of an object , the visible is alwayes judged to be in that part of space , from which , in a direct line , the last impression is made upon the sensorium . and this reason is of extent sufficient to include the full solution also of that problem , by alexander ( . de anima . ) so insulting proposed to the defendants of epicurus material actinobolisme visive , or the emanation of substantial images from the object to the eye : viz. why doth t●e image of a man move , when reflected from a mirrour , according as the man moves ? for , this phaenomenon we are to referr to the variation of the parts of the mirrour , from each of which it is necessary that a fresh reflexion of the species be made into the eye : and consequently , that the image appear moved , according to the various motions of the object . the necessity of this is evident from hence ; if you stand beholding your face in a glass , and there be divers others standing by , one at your right hand , another at your left , a third looking over your head in the same glass ; they shall all behold your image , but each in a distinct part of the glass . whence you may also understand , that in the looking-glass is not only that image , which you behold , but also innumerable others ; and those so mutually communicant , that in the same place , where you behold your nose , another shall see your chin , a third your forehead , a fourth your mouth , a fifth your eyes , &c. and yet doth no one see other then a simple and distinct image . moreover you may hence inferr , that in the medium is no point o● space , in which there is not formed a perfect image of the ●aye● concurring therein , and advenient from the same object ; though not from the same parts , or particles thereof : and consequently that in the whole medium there are no two images perfectly alike ; as also , that what the vulgar philosophers teach , that the whole image is in the whole space or medium , and whole in every part thereof , is a manifest falsity . for , though it may be said justly enough , that the whole image , i. e. the aggregate of all the images , is in the whole space : yet is there no part of that space , in which the whole image can be . to this place belongs also that problem ; why doth not the right hand of the image respond to the right of the object : but contrariwise , the left to the right , and right to the left ? the cause whereof consisteth onely in the images confronting the object : or , as plato ( in timaeo ) most perspicuously expresseth it , quia contrarijs visus partibus ad contrarias partes ●it contactus . understand it by supposing a second person posited in the place of the mirrour , and confronting the first : for , his right hand must be opposed to the others left . nor is the reason of the inversion of the parts of the image other than this ; that the rayes emitted from the right side of the object , are reflected on the left , and ● contra. just as in all impressions , or sigillations , the right side of the antitype responds to the left of the type . consule aquilonium , lib. . opt . proposit . . and , as for the reason of the restitution of the parts of the image to the right position of the parts of the object ; by two mirrours confrontingly posite● ▪ it may most easily and satisfactorily be explained by the decussation of the reflected rayes . to conclude . we need not advertise , that the optical problems referrible to this place , are , ( if not infinite ) so numerous , as to require a larger volume to their orderly proposition and solution , than what we have designed to the whole of this our physiology . nor remember you , that our principal scope in this chapter , was only to evince the prae●●inence of epicurus hypothesis above all others , concerning the reason and manner of vision ; and this by accommodating it to the verisimilous explanation of the most capital dif●●culties ▪ occurring to a profound inquest into that abstruse subject . all therefore that remains unpaid of our praesent debt , is modestly to referr it to your equitable arbitration ; whether we have deserted the doctrine of the aristoteleans , touching this theorem , and addicted ourselves to the sect of the epicureans , on any other interest , but that sacred one of verity : which once to decline , or neglect , upon the sinister praetext of vindicating any human auctority ; is an unpardonable profanation of reason , and high treason against the state of learning . chap. iv. the nature of colovrs ▪ sect . i. the rabbins , whenever they encounter any problem ; that seems too strong for their reason ; to excuse their despair of conquering it , they instantly recurr to that proverbial sanctuary , reservatur in adventum eliae , it belongs to the catalogue of secrets , that are re●erved for the revealment of elia● . and , ingenously , if any abstrus●●y in nature be so impervestigable , as to justifie our open profession of incapacity , and necessitate our opprest understanding to retreat to the same common refuge ; it must be this of the nature of colours , to the consideration whereof the clue of our method hath now brought us . for , though all philosophers unanimously embrace , as an indubitable verity , that the object of sight in general , is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , visible , whatever is deprehensible by that sens● ▪ and that , in particular , the proper and adequate object thereof , is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , colour , because nothing is visible but under the gloss or vernish of colour , nor doth light it self submit to the d●scernment of the eye , quate●us lux , in the capacity ofits form , or meerly as light , but instar albedinis , 〈◊〉 it retains to whiteness ; all which mersennus ( optic●e part . theorem . . ) hath judiciously contracted into this one theorem , ●bjectu● visus praecipuum est lux & color , vel lux colorata , aut color incidus : we say , notwithstanding this their ground-work be laid in the rock of manifest certitude , yet when they attempt to erect thereon an establisht and permanent theory of the essence of colours , either in their s●●ple and first natures , or complex and secondary removes ; they find the eye of their curiosity so obnubilated with dense and impervious difficulties , that all of certainty they can discover , is only this ; that their most subtle indagations were no more but anxious gropings in the dark , after that , whose existence is evidenced only by , and essence consisteth chiefly in light. but , this infelicity of our intellectuals will be more fully commonstrated by our abridged rehearsal of the most memorable opinions of others , and the declarement of our own , concerning this magnale . the despot of the schools ( in lib. de sensu & sensili , cap. . ) defines colour to be , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , the extremity of a diaphanum , or transparent body terminated : subjoining that colour appertains to all things , ratione perspicuitatis , and consequently , that the extremity of a perspicuous body terminated is the subject of colour . which that we may clearly understand , let us consult the great scaliger , who ( in exercit. . ) thus concisely comments thereupon . if the perspicuum ( saith he ) suffer condensation so far as to the amission of its transparency , and so prohibit the trajection of the visible species ; it instantly becomes colorate , and ought to be accounted terminate , because it bounds or limits the visive rayes . wherefore , the law of consequence injoineth , that we explore the essence of colours , in the gradual termination of the diaphanum ; and derive that termination ( ) from meer condensation , without the admixture of any other thing to the diaphanum ; as may be instanced in the starrs , for they become visible , though of a lucid nature , only because they are of a compact or dense contexture . ( ) from the admission of an opace with a translucid body ; as is exemplified in our culunary fire , which though in the simplicity of its most perspicuous , doth yet appear red , because commixt and in some degree obnubilated with fuliginous exhalations , from the pabulum or fewel thereof , or compound body in combustion . the same likewise is to be understood of aer and water ; for , those three elements are all perspicuous , though in divers degrees : fire being most perspicuous , aer possessing the next degree , and water coming behind them both , as seeming to be a medium betwixt perspicuity and opacity . and , therefore , from the admission of the parts of that opace element , earth , to any other of the three diaphanous ▪ one or other colour among the many must arise . but , the perspicuum passeth first into whiteness , and therefore is it that perspicuity , light and whiteness , are of the same nature , cozen germans once removed , and discriminate only by degrees : as , on the contrary , an opacum , darkness , and blackness are also cognate . ●his being the original of the two father , or ground colours : it can be no difficulty to attain the specifical causes of all others , since they are only intermediate , i. e. they arise from the various complexion or contemperation of the two extrems . and this is the sense of aristotles text , if we admit the interpretation of scaliger . plato , being either unable , or unwilling to erase out of the table of his mind some of the ingravements of democritus ; understands colour to be flammula quaedam , sive fulgor , è singulis corporibus emicans , partes habens visui accommodatas ( in timaeo ) . for , having held , as diogenes laertius ( lib. . ) hath well observed , and we may easily collect from that discourse of his , in the name of timaeus locrus ; that the world consisteth of the four elements , of fire , as it is visible , of earth , as tangible , of aer and water , ut proportione non vacet : lest he should apostate from his fundamentals , he affirmed , corpora videri propter ignem , & propter terram tangi , that the visibility of all things was radicated in their participation of fire , and their tangibility in their share of earth ; and consequently that the colour of bodies was nothing but an 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or emicancy of their internal fulgor , and the variety of its species dependent meerly on the various degrees , or more or less of that inhaerent luster . as for the pythagorean and stoick ; the former , with inexcusable incogitancy , confounded the tinctures of things with their extrems , allowing no real difference betwixt the superfice , and the colour it bears . pythagor●s colorem e●le extimam corporis superficiem censuit , hanc ob caussam ; quod color sectilem naturam habet , non tamen sit corpus , aut linea : as plutarch ( de placit . philosoph . ) and out of him , bernhard . caesius ( de mineral . lib. . cap. . sect. . art . . ) . the later , with unsatisfactory subtility , ( as if , indeed , he meant rather to blanch over the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or incomprehensibility of the subject , with ambiguous and sophistical terms , than confess , or remove it . ) makes colour to be 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , a certain efflorescence , arising from a determinate figuration of the first matter ; as we have collected from the memorials of plutarch ( lib. . de placit . philosoph . cap. . ) lastly , the illuminated sons of hermes , who boast to have , if not attained to the bottom of the mystery , yet out done the endeavours of all other sects of philosophers , in profounding it ; confidently lead our curiosity to their general asylum , the three universal principles , sal , sulphur and mercury , and tell us , that the elemental salts carry the mighty hand , or most potent energy in the production of colours . for , supposing three kinds of salt in all natural concretions ; the first a fixt and terrestrial , the second a sal nitre , allied to sulphur , the third a volatile or armoniac , referrible to mercury ; and that all bodies receive degrees of perspicuity , or opacity , respondent to the degrees of volatility , or terrestriety in the salts , that amass them : they thereupon deduce their various colours , or visible glosses , from the various commistion of volatile or tralucent salts , with fixt or obscure . now , notwithstanding all these sects are as remote each from other , as the zenith from the nadir , in their opinions touching the nature and causes , of colours , as to all other respects ; yet do they generally concur in this one particular , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , colores esse coh●rentes corporibus , that colours are congenite ▪ or cohaerent to bodies . which being manifestly repugnant to reason , as may be clearly evinced as well from the arguments alledged by plutarch ( . advers . colot . ) to that purpose , as from the result of our whole subsequent discourse , concerning this theorem : we need no other justification of our desertion of them , and adhaerence to that more verisimilous doctrine of democritus and epicurus , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , colorem lege esse , or more plainly in the words of epicurus , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ; colores in corporibus gigni , juxta quosdam , respectu visus ▪ ordines positusque . the probability of which opi●●●n , that we may with due strictness and aequ●n●mity examine ; and 〈◊〉 wh●t we formerly delivered , in our o●igine of qualities , touching th● possible causes of an inassignable variety of colours : we are briefly to advertise , first , that by the word , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , bodies , we are not to understand atoms , or simple bodies , for those are generally praesumed to be devoyd of all colour ; but 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , concretions , or compounds . secondly , that epicurus , in this text , according to the litteral importance thereof , and the exposition of gassendus , his most judicious and copious interpreter , had this and no other meaning . that in the extrems , or superficies of all concretions , there are such certain coordinations and dispositions of their component particles ( which , according to our first assumption in the immediately praecedent chapter , borrowed from the incomparable bullialdus , are never contexed without more or less of inaequality . ) as that , upon the incidence of light , they do and must exhibit some certain colour , or other , respective to their determinate reflection and refraction , or modification of the rayes thereof , and the position of the eye , that receives them . that from these superficial extancies and and cavities of bodies are emitted those substantial effluviaes , constituting the visible image ; which striking upon the primary organ of vision , in a certain order and position of particles , causeth therein a sensation , or perception of that particular colour . but , that these colours are not really cohaerent to those superficial particles , so as not to be actually separated from them , upon the abscedence of light : and , consequently that colours have no existence in the dark . moreover , that the substance of light , or the minute particles , of which its beams consist , are necessarily to be superadded to the superficial particles of bodies , as the complement , nay the principal part of colour : as may be inferred from these words of epicurus , registred by plutarch ( . advers . colot . ) quinetiam hâc parte ( luce , viz. ) seclusa , no● video , qui dicere liceat , corpora quae in tenebris in conspicua sunt , colorem habere . of which persuasion was also that admirable mathematician , samius aristarchus ; who positively affirmed ( apud stobaeum , in ecl. phys. . ) incidentem in subjectas res lucem , colorem esse ; ideoque constituta in tenebris corpora colore prorsùs destitui . to which , doubtless virgil ingeniously alluded in his — ubi coelum condidit umbra iupiter , & rebus nox abstulit atra colorem . and lucretius in his qualis enim coecis poterit color esse tenebris , lumine qui mutatur in ipso ; propterea quod recta aut obliqua percussus luce refulget ? &c. and , lastly , that light doth create and vary colours , according to the various condition of the minute faces , or sides of the particles in the superfice , which receive and reflect the incident rayes thereof , in various angles ▪ toward the eye . sect . ii. having thus recited , explicated , and espoused the conceptions of epicurus , of the creation of colours ; it behoves us to advance to the examination of its consistency with right reason , not only in its general capacity , but deduction and accommodation to particulars . but , first , to praevent the excess of your wonder , at that so paradoxical assertion of his , that there are no colours in the dark , or that all colours vanish upon the amotion or defection of light ; we are to observe that it is one thing to be actually colorate , and another to be only potentially , or to have a disposition to exhibit this or that particular colour , upon the access of the producent , light. for , as the several pipes in an organ , though in themselves all aequally insonorous , or destitute of sound , have yet an equal disposition , in respect of their figuration , to yield a sound , upon the inflation of wind from the bellows ; and as the seeds of tulips , in winter , are all equally exflorous , or destitute of flowers , but yet contain , in their seminal virtues , a capacity or disposition to emit various coloured flowers , upon the access of fructifying heat and moysture , in the spring : so likewise may all bodies , though we allow them to be actually excolor , in the dark , yet retain a capacity , whereby each one , upon the access and sollicitation of light , may appear clad in this or that particular colour , respective to the determinate ordination and position of its superficial particles . to inculcate this yet farther , we desire you to take a yard of scarlet cloth , and having extended it in an uniform light , observe most exactly the colour , which in all parts it bears . then extend one half thereof in a primary light , i. e. the immediately incident , or direct rayes of the sun ; and the other in a secondary , or once reflected light : and then , though perhaps , through the praeoccupation of your judgment , you may apprehend it to be all of one colour ; yet if you engage a skilful painter to pourtray it to the life , as it is then posited , he must represent the directly illuminate half , with one colour , viz. a bright and lightsome red , and the reflexly illuminate half , with another , i. e. with a duskish or more obscure red ; or shamefully betray his ignorance of albert durers excellent rules of shadowing , and fall much short of your expectation . this done , gently move the extended cloth through various degrees of light and shadow : and you shall confess the colour thereof to be varied upon each remove ; respondent to the degree of light striking thereupon . afterward , fold the cloth , as boyes do paper for lanterns , or lay it in waves or pleights of different magnitude ; and you shall admire the variety of colours apparent thereon : the l●minent and directly illustrate parts projecting a lively c●●nation , the lateral and averted yeilding an obscure sanguine , clouded with murrey , and the profound or unillustrate putting on so perfect sables , as no colour drawn on a picture can counterfeit it to the life , but the deadest black. your sense thus satisfied , be pleased to exercise your reason a while with the same example ; and demand of your self , whether any one of all those different colours can be really inhaerent in the cloth ? if you pitch upon the scarlet , as the most likely and proper ; then must you either confess that colour not to be really inhaerent , since it may , in less than a moment , be varied into sables , only by an interception of light : or admit that all the other colours exhibited , are aequally inhaerent ; which is more , we praesume , then you will easily allow . and , therefore , you may attain more of satisfaction , by concluding , that indeed no one of all those colours is really so inhaerent in the cloth , as to remain the same in the absence of light ; but , that the superficial particles of the cloth have inhaerent in them ( ratione figurae , coordinationis & positus ) such a disposition , as that in one degree of light it must present to the eye such a particular colour ; in another degree , a second gradually different from that ; in another , a third discriminate from both , until it arrive at perfect obscurity , or black. and , if your assent hereto be obstructed by this doubt , why that cloth doth most constantly appear red , rather then green , blew , willow , &c. you may easily expede it , by admitting , that the reason consisteth only herein , that the cloth is tincted in a certain liquor , whose minute particles are , by reason of their figure , ordination and disposition , comparate or adapted to refract and reflect the incident rayes of light , in such a manner , temperation , or modification , as must present to the eye , the species of such a colour , viz. scarlet , rather then a green , blew , willow , or any other . for , every man well knows , that in the liquor , or tincture , wherein the cloth was dyed , there were several ingredients dissolved into minute p●rticles ; and that there is no one hair , or rather no sensible part in the superfice thereof , whereunto myriads of those dissolved particles do not constantly adhere , being agglutinated by those fixative salts , such as sal gemmae , alum , calcined talk , alablaster , sal armoniack , &c. wherewith dyers use to graduate and engrain their tinctures . and , therefore of pure necessity it must be , that , according to the determinate figures and contexture of those adhaerent granules , to the villous particles in the superfice of the cloth , such a determinate refraction and reflection of the rayes of light should be caused ; and consequently such a determinate species of colour , and no other , result therefrom . now , insomuch , as it is demonstrated by sense that one and the same superfice doth shift it self into various colours , according to its position in various degrees of light and shadow , and the various angles , in which it reflecteth the incident rayes of light , respective to the eye of the spectator ; and justly inferrible from thence by reason , that no one of those colours can be said to be more really inhaerent than other therein , all being equally produced by light and shadow gradually intermixt , and each one by a determinate modification thereof : what can remain to interdict our total explosion of that distinction of colours into real or inhaerent , and false , or only ●pparent , so much celebrated by the schools ? for , since it is the genuine and inseparable propriety of colours , in general , to be apparent ; ●o suppose that any colour apparent can be false , or less real than other , is an open contradiction , not to be dissembled by the most specious sophistry ; as des cartes hath well observed ( in meteor . cap. . art . . ) . besides , as for those evanid colours , which they call 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , meerly apparent ones , such as those in the rainbow , parheliaes , paraselens , the trains of peacocks , necks of doves , mallards , &c. we are not to account them evanid , because they are not true : but , because the disposition of those superficial particles in the clouds , and feathers , that is necessary to the causation of them , is not constant , but most easily mutable ; in respect whereof those colours are no more permanent in them , than those in the scarlet cloth , upon the various position , extension , plication thereof . and charity would not dispense , should we suppose any man so obnoxious to absurdity , as to admit , that the greater or less duration of a thing doth alter the nature of it . grant we , for example , that the particles of water constituting the rorid cloud , wherein the rainbow shews it self , were so constant in that determinate position and mutuall coordination , as constantly to refract and reflect the incident beams of the sun , in one and the same manner ; and then we must also grant , that they would as constantly exhibite the same species of colours , as a r●inbow painted on a table : but , because they are not , and so cannot constantly refract and reflect the irradiating light , in one and the same manner ; it is repugnant to reason , thereupon to conclude , that the instability of the colours doth detract from the verity , or reality of their nature . for , it is only accidental , or unessential to them either to be varied , or totally disappear . so that , if you admit that sea green observed in the rainbow , to be less true , than the green of an herb , because its duration is scarce momentany in comparison of that in the herb ▪ you must also admit that green in the herb , which in a short progress of time degenerates into an obscure yellow , to be less true , than that of an emrauld , because its duration is scarce momentany , in comparison of th●● of the emrauld . but , perhaps ▪ praejudice makes you yet inflexible , and therefore you 'l farther urge ; th●t the difficulty doth cheifly concern those evanid colours , which ●●e appinged on bodies , reflecting light , by prisms or triangular glasse● , vulgarly called fools paradises : because these seem to have the least of reality , among all other reputed meerly apparent . and , in case y●● assault us with this your last reserve ; we shall not desert our station , for want of strength to maintain it . for , that those colours are as real , as any other the most durable , is evident even from hence ; that they have the very same materials with all other , i. e. they are the substance of light it self reflected from those objected bodies , ●nd ( what happens not to those eyes , that speculate them without a prism ) twice refracted . experience d●monstrates , that if a man look intently upon a polite globe , in ●hat part of it superfice , from which the incident light is reflecte● ▪ in direct lines toward his eye ; he shall perceive it to appear clad in another colour , than when he looks upon it from any other part of the medium , toward which the light is not reflected : and 〈…〉 he have no reason , why he should not account both those dif●●●ent colours to be true ▪ the reflection of light , which varieth the apparition according to the various position of the eye in several parts of the medium , nothing diminishing their verity . if so , why should not those colours created by the prism , be also reputed real ; the refraction of light , which exhibiteth other colours in the objected bodies , than appear in them without that refraction , nothing diminishing their reality ? by way of corollary , let us here observe ; that the colours created by light , reflected from objects on the prism , and therein twice refracted , are geminated on both sides thereof . for , insomuch as those colours are not appinged but on the extremes of the object , or where the sup●rfice is unequal ( for if that be plane and smooth , it admits only an uniform colour , and the same that appears thereon , when beheld without the prism ) : therefore are two colours alwayes observed in that extreme of the object , which respecteth the base of the triangle in the glass , and those are a vermillion and a yellow ; and two other colours in that extreme , which respecteth the top of the triangle , and those are a violet blew , and a grass green . and hence comes it , that if the latitude of the superfice be so small , as that the extremes approach each other sufficiently near ; then are the two innermost colours , the yellow and green connected in the middle of the superfice , and all the four colours constantly observe this order , beginning from the base of the triangle ; a vermillion , yellow , green , and violet , beside the inassignable variety of other intermediate colours , about the borders and commissures . we say , beginning from the base of the triangle ; because , which way soever you convert the prism , whether upward or downward , to the right or to the left , yet still shall the four colours distinguishably succeed each other in the same method , from the base : however all the rayes of light reflected from the object on the prism , and trajected through it , are carried on in lines parallel to the base , after their incidence on one side thereof , with the obliquity or inclination of near upon thirty degrees , and refraction therein to an angle of the same dimensions ; that issuing forth on the other side , they are again refracted in an angle of near upon degrees , and with the like obliquity , or inclination . these reasons equitably valued , it is purely consequent , that no other difference ought to be allowed between these emphatick , or ( as the peripatetick . ) false colours , and the durable or true ones , than only this ; that the apparent deduce their creation , for the most part , from light refracted in diaphanous bodies , respectively figurated , and disposed , and sometimes from light only reflected : but , the inhaerent , or true ( as they call them ) deduce theirs from light variously reflexed in opace bodies , whose superficial particles , or extancies and cavities are of this or that figure , ordination , and disposition . not that we admit the durable colours , no more than the evanid , to be formally ( as the schools affirm ) inhaerent in opace bodies , whose superficial particles are determinately configurate and disposed to the production of this or that particular species of colou●● , and no other : but only materially , or effectively . for , the several species of colours depend on the several manners , in which the minute particles of light strike upon and affect the retina tunica ; and therefore are we to conceive , that op●●e bodies , reflecting light , do create colours only by a certain modification or temperation of the reflected light , and respondent impression thereof on the sensory : no otherwise than as a needle which though it contain not in it self the formal reason of pain , doth yet materially , or effectively produce it , when thrust into the skin of an animal ; for , by reason o● its motion , hardness , and acuteness , it causeth a dolorous sensation in the part perforated . to diminish t●● difficulty yet more , we are to recognize ; th●t the first matter , or catholique principles of all material natures , are absolutely devoyd of all sensible qualities ; and that the qualities of concretions , such as colour , sound , odour , sapor , heat , cold , humidity , siccity , asperity , smoothness , ha●dness , softness , &c. are really nothing else but various modifications of the insensible particles of the first matter , relative to the va●ious organs of the senses . for , since the org●ns of the sight , hearing , ●asting , smelling , and touching , have each a peculiar contexture of the insensible particles that compose them ; requisite it is , that in concretions there should be various sorts of atoms , some of such a special magni●●●● , figure and motion , as that falling into the eye , they may conveniently move or affect the principal sensory , and therein produce a sensation of themselves ; and that either grateful or ingratefull , according as they are commodious or incommodious to the small receptaries thereof ( for the gratefulness or ingratefulness of colours ariseth from the congruity or incongruity of the particles of the visible species , to the receptaries or sm●ll pores in the retina tunica ) : some , in like m●nner , that may be conv●nient to the organ of hearing ; others to that of smelling , &c. so that , though atoms of all sorts of magnitude , figure and motion contexed into most minute masses , arrive at all the organs of sense ; yet may the eye only be sensible of colour , the ear of sound , the nostrils of odour , &c. again , that colour , sound , odour , and all other sensible qualities , are 〈◊〉 according to the various situation , order , addition , detraction , transposition of atoms ; in the same manner as words , whereof an almost infinite ●ariety may be composed of no more then letters , by their various sit●●tion , order , addition , detraction , transposition ; as we have more cop●●●sly discoursed , in our precedent original of qualities . sect . iii. to descend to particulars . it being more than probable , that the various species of colours have their origine from only the various manners , in which the incident particles of light , reflected from the exteriours of objects , strike and affect the principal sensory ; it cannot be improbable , that the sense of a white colour is caused in the optick nerve , when such atoms of light , or rayes consisting of them , strike upon the retina tunica , as come directly from the lucid fountain , the sun , or pure flame ; or reflexedly from a body , whose superficial particles are polite and sphaerical , such as we have formerly conjectured in the smallest and hardly distinguishable bubbles of froth , and the minute particles of snow . and , as for the perception of its contrary , black , generally , though scarce warrantably reputed a colour ; we have very ground for our conjecture , that it ariseth rather from a meer privation of light , than any material impression on the sensory . for , blackness seems identical , or coessential with shadow : and all of it that is positively perceptible , consisteth in its participation of light , which alone causeth it not to be absolutely invisible . and hence is it , that we have several degrees , or gradual differences of black , comparative to the several degrees of shadow , progressing till we arrive at perfect darkness : and that we can behold nothing so black , which may not admit of deeper and deeper blackness , according to its greater and greater recess from light , and nearer and nearer access to absolute opacity . to reason , therefore , is it consonant that all bodies , whose natural hew is black , are composed of such insensible particles , whose surfaces are scabrous , rough , or craggy , and their contexture so rare , or loose , as that they rather imbibe , or swallow up the incident rayes of light , than reflect them outwardly toward the eye of the spectator . of this sort , the most memorable , yet discovered , is the obsidian stone , so much admired and celebrated among the romans ; whose substance being conflated of scabrous and loosely contexed atoms , causeth it to appear a perfect negro , though held in the meridian sun-shine : because the rayes invading it are for the most part , as it were absorpt and stifled in the small and numerous caverns and meanders variously interspersed among its component particles . which common and illiterate eyes beholding , delude their curiosity with this refuge ; that it hath an antipathy to light , and doth therefore reflect it converted into shadows . the generation of the two extreme and ground colours , white and black , being attained by this kind of inquest into the rolls of reason ; the former deriving it self from light ; either immediately and in direct lines profluent from its fountain ; or by reflection from bodies , whose superficial particles are sphaerical and polite ; the later from the negation of light : there can be no great difficulty remaining concerning the genealogy of all other intermediate ones , since they are but the off-spring of the extreme , arising from the intermission of light and shadow , in various proportions ; or , more plainly , that the sense of them is caused in the retina tunica , according to the variety of reflections and refractions , that the incident light suffers from the superficial particles of objects , in manner exactly analogous to that of the evanid colours , observed in sphaerical glasses , replete with water , in prismes interposed betwixt the object and eye , in angular diamonds , opalls , &c. for , even our sense demonstrates , that they are nothing , but certain perturbations , or modifications of light , interspersed with umbrellaes , or small shadows . the verisimility of this may be evinced from the sympathy and antipathy of these intermediate colours , among themselves . for , the reason , why yellow holds a sympathy , or symbolical relation with vermillion and green , and green with sky-colour and yellow , ( as the experience of painters testifieth , who educe a yellow pigment out of vermillion and green , in due proportions commixt , upon their palatts : and reciprocally , green out of yellow and sky-colour , in unaequal but determinate quantities contempered ) is no other but the affinity of their respective causes , or only gradually different manners of light reflected and refracted , and intermixt with minute and singly imperceptible shadows . and , on the contrary , the reason of the antipathy , or asymbolical relation betwixt a saffron yellow and a caerule , betwixt a green and a rose colour , into which a saffron yellow degenerates , and betwixt a yellow and purple , into which a caerule degenerates : can be nothing else , but the dissimilitude or remoteness of their respective causes ; since things so remotely discrepant , are incapable of conciliation into a third , or neutral , or ( rather ) amphidectical nature , but by the mediation of something , that is participant of both . this the philosopher glanced at in his ; colores misceri videntur , quemadm●dum soni ; ita enim qui eximium quoddam proportionis genus servant , hi consonantiarum more , omnium suavissimi sunt , ceu purp●reus & puniceus , &c. ( de sens . & sensil . cap. . ) we say , that all these intermediate colours emerge from the various intermistion of light , and small shadows ; because , to the production of each of them from reflected , or refracted light , or both , the interposition of minute , and separately invisible shadows , is indispensably necessary . which may be evidenced even from hence , that colors are not by prismes appinged on bodies , but in their margines or extremes , there where is not only the general commissure of light and shadows ; but also an inaequality of superfice : which , by how much the more scabrous or rough , by so much the more are the colours apparent thereon , ampliated in latitude . for , since there is no superfice , however smooth and equal to the sense , devoid of many extancies and cavities ; as we have more then once profestly declared : it is of necessity , that betwixt the confronting sides of the extancies , reflecting the rays of light hither and thither , there should be intercedent small shadows , in the interjacent cavities , from which no light is reflected . and hence is it , that in an object speculated through a prism , the caerule colour appears so much the more dense and lively , by how much the nearer to the limbus , or extreme of the object it is appinged ; because , in that place , is the greater proportion of small shadows : and è contra , so much more dilute and pale ▪ by how much farther it recedeth from the margin , insomuch that it degenerates , or dwindles at last into weak sea-green , or willow , in its inmost part ; because , in that place is the greater proportion of light. conformable to that rule of athanas. kircher . ( art. magn. lucis & umbrae . lib. . part . . cap. . ) differunt autem & umbra & fulgores , majore & minore vel candore , & nigrore , prout vel fonti lucis , aut tenebrarum propriores fuerint , vel à fonte longius recesserint , in quo luce & obscuritate summa sunt utraque . unde patet , quantò fulgores a luce magis recesserint , tanto plus nigredinis ; & quantò a tenebris magis recesserint umbrae , diminuto nigrore , tanto plus albedinis acquirere : quae omnia visus judicare potest . the same , proportionately , we conceive to hold good also in all bodies , whose colours are genuine , or apparent to the naked eye : chiefly because we may lawfully conceive , that every particle of every hair in a scarlet , or violet coloured cloth , is consimilar in disposition to the particles in the extremes of an object speculated through a prism : and hold it purely consequential thereupon , that light may arrive at the eye from them , with the like reflections and intermistion with shadows , as from the extremes of the reflectent body , through the glass , which advanceth its commixture with small shadows . and what we affirm of scarlet and violet , may also , with no less congruity , be accommodated to yellow and sea-green ; allowing the same proportion and modification of light and shadows in them as in that part of the superfice of any other body , on which the prism doth appinge them : and in like manner to all other colorate objects , whose tinctures bear any affinity to either of these four specified , or arise from the complexion of any two or more of them . but here we are arrested by two notable , and to our praecedent theory seemingly inconsistent problems : which though of difficulty enough to deserve the wealthy speculations of archimedes , do yet require from us at least a plausible solution , on the paenalty of no less than the loss of reputation , and the posting up a writ of bankrupt against our reason , by that austere creditor , curiosity . ( ) how comes it , that those two so discrepant and assymbolical colours , created by a prism , vermillion and caerule , arise from causes so cognate ; the former only from the commistion of a greater proportion of light with a less of shadows ; the later from a less proportion of light with a greater of shadows ? ( ) why , when those two colours emphatical , vermillion and carule are by a prism intermediate , projected on a wall or sheet of white paper beyond it , from the light of a candle ; if you put your eye in that place , ●n which either of the two colours is appinged , so that another person , conveniently posited in the same room , may behold the same distinctly shining on the pupil of your eye ; yet shall you plainly and distinctly perceive the other colour in the glass ? for example ; if the vermillion appear on your eye , you shall nevertheless clearly see a caerule in the glass : and transpositively , though your eye be manifestly and totally tincted with a carule , yet shall you see a vermillion . touching the former , we shall adventure to desume the solution thereof meerly from the figure of the prisme , and determine the reason on this only ; that the rayes of light arriving at the base of the triangle , are trajected through it by a longer tract or way , than those arriving at or nearer to the top thereof : and therefore , the glass being in that part most crass , there must be more impervious particles obsistent to the rayes of light ; each one whereof repercussing its raye back again into the medium from the glass , causeth that the number of shadowes is multiplyed in that part of the object , which the base of the triangle directly respecteth ; and consequently produceth a caerule tincture thereon . such as that , not only by vulgar , but many transcendently learned heads adscribed to the firmament ▪ which yet belongs rather to that vast ( many have said infinite ) space betwixt it and our terrestrial globe , being caused by the rayes of the coelestial lamps , from swarms of minute bodies interposed , thinly reflected toward our eyes : for , each of those impervious particles swarming in that immense space , must repercuse a ray of light deradiated from above , and so by multiplying the number of shadows , make the firmament ( which otherwise , according to probability , would wear the mourning livery of midnight ) appear totally invested in an azure mantle . this , though meer conjecture ( and , indeed , the subject is too sublime to admit of other than conjecture , since st. paul hath left us no observation concerning it , in his rapture up into the third heaven , and the design of the ganzaes is desperate ) hath in it somewhat more of reason , then that confident conceipt of athanas. kircherus ( art. magn. lucis & umbrae , lib. . part . . cap. . de chromatismis rerum naturalium . ) medium inter utrumque caeruleum , proximum , viz. à nigro , seu tenebroso , colorem ad jucundissima illa caelorum spatia , inoffenso visu contemplanda , natura providentissima mundo contulit , &c. that the providence of the creator chose this azure tincture to invest the firmament withal , as the middle colour between the two extreams , white and black , that so our sight might not , when we speculate that universal canopy , be either perstringed with the excessive lustre of the one , nor terminated by the absolute opacity of the other . because , if the natural colour of the firmament were azure , as he praesumes ; then would it , by reason of the vast space betwixt it and our sight , and the repercussion of the greatest part of the rayes of light , from our eye , by those myriads of myriads of myriads of small bodies replenishing that intermediate space , necessarily appear of some other colour : the experience of sea-men assuring , that all colours , ( white and that of pure flame , retaining to whiteness , only excepted ) lose themselves in long trajection through the medium , and that even land , which is but few degrees removed from opacity , appears to the first discovery like a blewish cloud lying level to the horizon . it being certain , therefore , that by how much the farther any colour recedeth from whiteness , by so much the less way it is visible ( which the graecian intimates in the word , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , albus , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quod procul videatur . ) and that even the earth , an opace body , to sea-men first kenning it , at large distance , appears clad in a kind of obscure blewish mantle : it cannot bee dissonant to reason to conceive , that the natural colour of the firmament cannot be azure , since it so appears to us ; and that it is rather opace , because it appears azure , when illustrate by the reflected light of the coelestial luminaries . again , because the rayes of light , incident on the top of the prism , are trajected through it by a shorter cut , or passage , than those incident on the base ; and so meet with fewer impervious and retundent particles , the glass being in that part thinnest : therefore is the number of shadows much less in that part of the object , which respecteth the cone or top of the triangle , than in that , which confronts the base ; and those few shadows which remain undiminisht , being commixt with a greater number of lines of light , are transformed into the species of a vermillion red. such as that daily observed in the impure flame of our culinary fires ; which having many particles of fuligenous exhalations commixt with its pure luminous particles , that continuedly ascending , avert as many rayes of light from the eye of the spectator , and so in some degree obnubulate it throughout : doth therefore put on the semblance of redness . or such as the sun and moon , commonly wear at their rising ; when the minor part , though many of their rayes are re●used , and averted from our sight , by the particles of dense vapours diffused through the spatious medium . however this may be disputed , yet is it warrantable to conceive , that the superficial particles of all bodies , clad in either of these liveries , vermillion and caerule , may have in their contexture obtained such a disposition , as to reflect light permixt with small shadows , in that definite temperation , or modification , in which it usually arrives at the eye , after its trajection through a prism ; when it thereupon impresseth the sense of a vermillion , or caerule . as for the enodation of the later difficulty , it is comprehended in the reasons of the former . for , it being certain , that the vermillion projected by a prisme , doth consist of a greater proportion of light mingled with a less of shadows , and the caerule , on the contrary , of a greater proportion of shadows interspersed among the lines of a less light ; and as certain , that the vermillion appeareth on that side of the prisme , where the light is more copious , as therein meeting with fewer retundent impervious particles , in the substance of the glass ; and the caerule in that part , where the light is diminished , as meeting with more impervious particles , and being by them repercussed : it must inevitably follow thereupon , that , if an opacous body be posited within the bounds of this light , so that the light may fall on each side thereof , and as it were fringe it ; a symptome quite contrary to the former shall evene , i. e. the vermillion will appear on that side of the species , which is over against the caerule , and the caerule will be transposed to that side of the species , which confronteth the vermillion . this is easily experimented with a piece of narrow black ribbon affixt longwise to either side of the prisme . for , in that case , the light is bipartited into two borders , or fringes , the opace part veyled by the ribbon on each side environed with light , and each border of light environed with two shadows ; or , more plainly , between each border of shadows conterminate to each extreme of light , trajected through the unopacate parts of the glass : and , therefore , in the commissure of each of the two lights with each of the conterminous shadows , there must be vermillion on one side , and caerule on the other . now to drive this home to the head , the solution of the present problem ; the reason why , when the light of a candle is trajected through a prism , on a white paper or wall , posited at convenient distance beyond it , and there transformed into these two luminous colours , vermillion and caerule , if you put your eye in that place of the paper or wall , whereon the vermillion shines , you shall perceive only the caerule in the glass , and è contra : we say , the reason of this alteration of site in the colours seems to be only this , that the circumstant aer about the flame of the candle being opacous , and so serving in stead of two blacks to environ the borders of light , causeth that side of the candle , which is seen through the thicker part of the glass , to appear blew ; and that which is seen through the thinner , to appear red ; according to the constant phaenomenon in prismes . but , if the species be beheld by reflection from any illustrate and repercussing body , such as the paper , or wall , then must the series or method of the borders of light and shadow be inverted , for the reason immediately praecedent , and consequently , the situation of the colours , emergent from their various contemperations , be also inverted . and thus have we , by the twilight of rational conjecture , given you a glimpse of the abstruse original of the extreme and simple colours ; and should now continue our attempt to the discovery of the reasons of each of those many compound ones , wherewith both nature and art so delightfully imbellish most of their peices : but , since they are as generally , as rightly praesumed to be only the multiplied removes of light and darkness , i. e. to be educed from the various commixtures of the extreme , or simple , or both ; and so it cannot require but a short exercise of the intellect to investigate the determinate proportions of any two , or more of the simple ones , necessary to the creation of any compound colour assigned ( especially when those excellent rules of that modern apelles , albertus durerus , praescribed in his art of limning ; and the common experience of painters , in the confection of their several pigments , afford so clear a light toward the remove of their remaining obscurity , and the singling out their particular natures ) : we cannot but suppose , that any greater superstructure on this foundation , would be lookt upon rather as ornamental and superfluous , than necessary to the entertainment of moderate curiosity . especially when we design it only as a decent refuge , for the shelter of ingenious heads from the whirlwind of admiration : and not as a constant mansion for belief . for , as we cautiously praemonished , in the first article , the foundation of it is not layed in the rock of absolute demonstration , or de●umed a priori ; but in the softer mould of meer conje●ture , and that no deeper than a posteriori . and this we judge expedient to profess , because we would not leave it in the mercy of censure to determine , whether or no we pretend to understand , what are the proper figures and other essential qualities of the insensible particles of light ; with what kind of vibration , or evolution they are deradiated from their fountain ; what are the determinate ordinations , positions , and figures of those reflectent and refringent particles in the extreams of bodies , diaphanous and opace , which modifie the light into this or that species of colour ; what sort of reflection or refraction , whether simple or multiplyed , is required to the creation of this or that colour ; what are the praecise proportions of shadows , interwoven with light , which disguise it into this or that colour . besides , had we a clear and apodictical theory of all these nice●ies ; yet would it be a superlative difficulty for us to advance to the genuine reasons , why light , in such a manner striking on the superfice of such a body , therein ; suffering such a reflection or refraction , or both , and commixt with such a proportion of shadows in the medium , should be transformed into a vermillion , rather then a blew , green , or any other colour . again , were our understanding arrived at this sublimity , yet would it come much short of the top of the mystery , and it might hazard a dangerous vertigo in our brains to aspire to the causes , why by the appulse of light so or so modified , there is caused in the eye so fair and delightful a sensation ; as that of vision ; and why the sentient faculty , or soul therein operating , becomes sensible not only of the particular stroak of the species , but also of the colour of it . for , where is that oedipus , that can discover any analogy betwixt the retina tunica , optick nerve , brain , or soul therein resident , and any one colour ? and yet no man can deny that there is some certain analogy betwixt the species and sensory : since otherwise there could be no patibility on the one part , nor agency on the other . we are not ignorant , that the aspiring wit of des cartes hath made a towring flight at all these sublime abstrusities , and boldly fastned the hooks of his mechanick principles upon them , thinking to stoop them down to the familiar view of our reason . but supposing that all colours arise from the various proportions of the process and circumvolutions of the particles of light in bodies respective to various dispositions of their superficial particles , which accordingly more or less accelerate , or retard them ; as he hath copiously declared ( in dioptric . cap. . & meteor . cap. . ) : and erecting this upon his corner stone , or grand hypothesis , that light is nothing but an appulse or motion of the aether ; or most subtile , and so most agile matter in the universe ; which is meerly praecarious , and never to be conceded by any , who fears to ensnare himself in many inextricable difficulties , incongruities , and contradictions , in the deducement of it through all the phaenomena of light , colours , and vision : all that we can allow him , as to this particular , besides our thanks for his laborious endeavours , is that close of phaetons epitaph , magnis tamen excidit ausis . chap. v. the nature of light . sect . i. in our three immediately praecedent chapters , we have often mentioned the rayes of light , as the material principle both of all visible species , and colours ; and that we may not leave our reader unsatisfied in any particular , the communication whereof seems necessary , or advantageous to his full comprehension of all our conceptions relating to those arguments , or any other of affinity to them , that may hereafter occurr : we judge it our duty , here to let him clearly know , what notion we have of the nature of that so admirably glorious and universally comfortable an entitie , light. by the rayes of light , we understand , certain most tenuious streams of igneous particles in a continued fluor , and with ineffable pernicity succeding each other in direct lines , either immediately from their lucid fountain , or mediately from solid bodies reflecting them , towards the eye , and sensibly affecting the same . this description may receive somewhat more both of perspicuity and credit , if we consider the parallelism , or analogy , that each distinct ray of light holds to a stream of water , exsilient from the cock of a cistern , or tube of an arti●icial fountain . for , the reason why a stream of water issues from a tube in a kind of arch , and flows to some distance from its source through the aer ; is only this , that the particles of water first exsilient , upon the remove of the stopple or obstacle , are so closely and contiguously pursued by other particles immediately following , and those again by others indesinently emanant , that they are impelled forward and driven on with such rapidity , as overcomes their natural propensity to direct descent , by reason of their gravity , and carries them in a tense line from the vent so long as their impulse is superior to that of their gravity ; which encreasing more and more in each degree of distance , doth at length become victor over the force of the motion , and praecipitate them downright . and as this gradual tensity , or rigidity of a stream of water ariseth to it only from the pressure or impulse of the antecedent particles by the consequent , in an uninterrupted succession : so may we conceeve , that a ray of light , or wand ( many of our modern and most discovering philosophers call a stream of light , virgula lucis ; and that by an unstrained metaphor . ) consisting of many rayes seemingly united , such as we observe shining in a room through some hole in the window , or other inlet ; doth therefore become in a manner tense , or direct , only because the particles first emanant from the lucid fountain are so urged and prest on by the subsequent , and those again by others , with equal pernicity , that they cannot deflect from a direct line , or obey the inclination of their gravity , until some solid body , interposed , cut off the fluor , by interrupting the succession , and then the tensity , or pressure ceasing , the particles become incontiguous and disappear : as is observable , upon closing the inlet , through which a stream of light is admitted into an otherwise ●pace room . for , immediately the successive supply of luminous particles being intercepted , the antecedent droop , fail , and surrender that part of space , which they possest with splendour sufficient to affect the sense , to the horrid encroachment of darkness . this full comparison praemised , we shall comply with opportunity , and here concisely observe ( ) that aquilonius , and most other opticomathematicians do excellently distinguish light into so many gradual differences , as are the reflections of which it is capable ; denominating that light , primary , whereby a body is immediately , or in direct lines from the lucid fountain , illustrated ; that secondary , which reflected from one solid body , illuminates a●other ; that a third light , which illuminateth a body , after two reflections from others : and so forward up to the centenary , and millenary light , if , at least , it be capable of so many reflections , from bodies most solid and polite . ( ) that light at second hand is more weak than at first ; at third than at second ; at fourth than at third , &c. or , that light becomes so much weaker , by how many more reflections it hath suffered . not ( as is vulgarly concluded ) that a reflex ray is less tense , or the successive pressure of its particles less violent or rapid , than those of a direct ; for , the motion of light , however frequently reflected , is incomprehensibly swift : but , that every reflection doth much diminish it , some rayes being always diverted and scattered into other parts of the medium , by reason of the asperity , or inaequality of the particles in every superfice ; and so there being no superfice that remits in a direct line the full number of rayes ( some have adventured to say , scarce half so many as ) it received , and consequently the eye receiving fewer and fewer rayes successively from every reflectent , must be more weakly affected and moved by the thin remainder . for , if all the rayes of the sun directly incident on a wall , were thence reflected on another wall situate at a right angle ; the second wall would be fully as luminous as the first ; and consequently , the secondary light would be as strong and resplendent as the primary : but , since the superfice of the first wall is unequal and scabrous , it must of necessity come to pass , that though many of the rayes incident thereon are from thence projected on the second , yet as many are repercussed into other regions of the medium , some upward , others downward ; some to the right hand , others to the left , &c. according to the various faces , or sides of the small particles , with asperity contexed in the superfice of each stone therein . so that one half , if not the major part of the directly incident rayes being diverted from the second wall , the light thereon appearing must be proportionately less strong and fulgent , than that , which illuminates the first . by the same reason , if the second wall by reverberation derive the light to a third ; it must likewise play the publican , and remit but half so many rayes , as it received from the first : and so must the third transmit a thinner stock of light to a fourth , and a fourth to a fifth , &c. if this example seem scarce praegnant enough , let us descend into a deep pit , or with the troglodites creep into the bowels of some subterraneous cavern , and there our sense will demonstrate , that multiplied reflections of light gradually diminish it even to absolute insensibility . for , the rayes of the sun falling into the aperture of either mine , or long cave , are by oblique repercussions from their sides conveyed inwards , and so often bandied from side to side , that few or none attain to the bottom to diminish the opacity thereof : every reflection remitting some rayes , more or less , toward the mouth of the pit , or cave . and this ushers in our third observable . ( ) that aristotles assertion , lumen esse in continuo motu , that light is in perpetual motion , or reverberated to infinity ; is profound and orthodox . for , notwithstanding the illusion of our sense persuades us , that all things in the aer about us , and within our houses , are calm and unmoved : yet doth that better criterion , our reason , assure that the light diffused through the aer is in perpetual inquietude , and consisteth of nothing else but a most tenuious contexture of innumerable rayes , swarming from and to all regions uncessantly , so long as the lucidum ceaseth not to maintain the succession of fresh rayes , that may be reflected from all obvious bodies . so that in what ever part of the medium the eye is posited ; it shall ever have some object or other praesented : and particularly that , from whence some rayes are more directly reflected into its pupil . not that we conceive the light diffused through the whole aer to be continued , or united in all points , as are the parts of water in the sea : but , that , as a spiders web appears to be one entire and united body , though it consist of distinct filaments , variously intricate , and mutually decussating each other ; so also is light , non unum quid simplicissimum , sed compositissimum , some one thing not most simple or consisting of parts continuedly united , but most compound , or consisting of parts so interwoven as to exclude all sensible discontinuity ; though our sense deprehend it to be incompositissimum ▪ because the acies of the sight is too blunt to discern the single rayes , which like most slender filaments with exquisite subtilty interwoven into a visible invisible web , replenish the whole medium . ( ) that , though light be ever debilitated by reflection , yet is it many time corroborated by refraction ; as that transmitted through convex glasses , and glass vials replete with limpid water : and then only debilitated , when it is refracted by a concave superficies of a pellucid body , or after refraction on a plane superfice , is lookt upon obliquely . for as no reason can be given for the debilitation of light by reflection ; but the attenuation or dimmution of the number of its rayes : so can none be assigned for the corroboration of it by refraction in a convex glass , or vial filled with clear water ; but the multiplication of its rayes , in some part of the medium . nor is there , on the contrary , why we should conceive light to be made weaker by some refraction , unless in this respect only ; that if it had not fallen foul of a refringent body , a greater number of rayes would have continued their direct progress in a closer order , or more united stream : and so their debility depends meerly on their disgregation ; not diminution of pernicity . certainly , that light which is corroborated by refraction in a convex glass , would be yet more strong and energytical , if all those rayes , that strike upon the obverted side of the glass , were so refracted , as to permeate and unite in the aer beyond the averted side thereof : and those rayes which are trajected through the bottome of a glass vial filled with water , arrive at the eye so much the more disgregate , by how much the more obliquely the eye is posited ; because the water being in the bottom more copious , and so containing more retundent particles , doth divert the greatest number of them into the ambient . and hence we inferr , that if the beams of the sun be conceded more weak in the morn and evening than at noon , only because of a greater refraction by more vapours then interposed ; that effect must chiefly arise from hence , that the rayes come unto us obliquely , after their trajection through those swarms of denser vapours , and consequently more dissipated , the major part of them being diverted into other regions of the medium . moreover , insomuch as all masters in the optiques clearly demonstrate that the image of an illustrate object , speculated through water in the bottome of a vessel indiaphanous , doth appear less lively to those , that look on it obliquely , than to those that behold it in direct lines respective to the tendency of the light refracted by the water ; and that the superfice of every object hath so much the fewer parts discernable , by how much more obliquely it is speculated : therefore is it purely necessary , that the image of an object appear more contracted , when speculated by a vertical line , than when exhibited to the eye in a direct , and irrefracted one . and this also we judge to be in some part the cause , why the sun when nearest to our horizon , either orient or occident , appears in a figure more elliptical or oval , than sphaerical : for then do we behold it per lineam verticalem . we say , in part ; because the same effect may also be induced by the form of the vaporous sphaere . however this may be controverted , yet most certain it is , that the lucid image of the sun is alwayes more vitiated , when it arrives at our ●ight from an humble position , than a sublime or meridional : non quod pauciores quidem radij directi mane , quàm meridie ; sed ●eflexi tamen pauciores , qui cum illis misceantur , ipsorumque vim augeant . quia directi supra liberam horizontis planitiem praetereant , nec redeant ; cum sub meridiem in terram impacti non resilire regredique non valeant ; as gassendus , in epist. ad bullialdum , de apparent . magnitud . solis humilis & sublimis . and this hath a near relation to our fifth observable . ( ) that the body from which the rayes of a lucid object more eminently the sun , are repercussed so as to diminish the shadow round about it , seems not to be the conterminous aer , but rather some opacum constitute beyond both it and the aer . not that we deny the necessary reflection of many of the luminous rayes proceeding from the sun , by those myriads of myriads of particles floating in the atmosphere ; and so the remission of them back again toward their source , and the consequent diminution of the shadow invironing the same : but that we conceive the proportion of rayes so diverted , to be so small , as to be much below the observation of our sense . for , he that is in the bottom of a deep mine , hath his sight so little advantaged by the aer illuminated by the meridian beams of the sun , that though he can clearly behold the starrs in the firmament , immensely beyond that vast tract of aer then illustrate ; yet can he hardly perceive his own hand , or ought else about him , since all the rayes of light , which affect his eyes , are only those few that have escaped repercussion upward , by those many oblique refractions in the sides of the mine . thus also in the night are we no whit relieved by the aer , or aether surrunding our horizon , or more properly , our hemisphere beyond that region , to which the cone of the earths shadow extends : though the sun doth as freely and copiously diffuse its light through all that vast ocean of aer , or aether beyond the extent of the earths shadow , at our midnight , or when it is vertical to the antipodes , as at our noon when it is vertical to us : which could not be , if any sensible proportion of light were reflected toward us by the particles of the aer , or aether , replenishing the subcaelestial space . hence comes it , that what light remains to our hemisphere in the night , ought to be referred , not to any reflection of the suns rayes from the sublime aer , or aether ; but to the stars , or moon , or both . and this is also no contemptible argument , that the concave of the firmament is opace , and not azure , as most suppose . ( ) that every lucid bodie is considerable in a double capacity ; ( ) qua lucidum , as shining with either native , or borrowed light , it illuminateth other bodies : ( ) qua visibile , as it emits the visible image of it self . in the first respect , we may conceive it to be the center , from which all its luminous rayes are emitted by diffusion sphaerical , according to that establisht maxime of alhazen , omne punctum luminosum radiare sphaeralitèr : in the second , we may understand it to emit rayes in a diffusion pyramidal , the base whereof is in it self , and cone in the eye of the spectator . for , particularizing in the sun , which being both a lucid body and a visible object , falls under each acceptation ; we must admit the rayes thereof illuminating that vast ocean of space circumscribed by the concave of the heavens , to be deradiated from it sphaerically , as so many lines drawn from one common centre ; because they are diffused throughout a region far greater than the sun it self : and those rayes , that constitute the visible images of it , stream from it in cones or pyramids ; because they are terminated in the pupil of the beholders eye , a body by almost infinite degrees less than it self . this is fully demonstrated by the forms of eclipses , which no man can describe but by assuming the sun as the base , from whose extremes myriads of rayes emanant , and in their progress circularly environing the margin of the earth , or moon , pass on beyond them till they end in a perfect cone ; the orbs of the earth and moon being by many degrees less in circumference , than that of the sun. this confirms us , that those optico-mathematicians are in the centre of truth , who teach , that the rayes of the sun , and all other luminous objects as they constitute its visible species , are darted only pyramidally ; insomuch as they are received in the eye of each spectator , so much less than the sun , or other luminary : but that they progress in a sphaerical diffusion , in respect of the circumambient aer , in each point whereof the luminary or lucidum is visible . since , should we allow the concave of the firmament to be as thickly set with eyes , as joves vigilant pandars head was imagined by poets ; we could not comprehend how the orb of the sun could be discernable by them all , unless by conceding this sphaerical diffusion of pyramids to all parts of the same . and this doth as well illustrate as confirm a former antiperipatetical paradox of ours , that the visible species of an object is neither total in the totall space , nor total in every part thereof ; but the general image is in the whole medium , and the partial or particular images , whose aggregate makes the general image , in the singular parts of the medium : because no singular eye from any singular part of the medium , can perceive the whole of the object , but those parts only , which are directly obverted to that part of the medium , in which the eye is posited . which assertion we inferred from hence , that not only the whole , but also every sensible particle of an object doth emit certain most subtile rayes , constituting the species of it self , in a sphaerical diffusion , so that the various particles emit various rayes , that variously decussate and intersect each other , in all parts of the medium : and as these rayes are emitted sphaerically , ex se ▪ according to that maxime , omne visibile sui speciem effundere sphaeraliter ; so do most of them , ex accidente , convene in their progress , and so reciprocally intersect , as to fulfill the figure of a pyramid . whence it naturally follows , that because some rayes must convene , in all parts of the medium , in this manner ; therefore are pyramids of rayes made in all points of the medium , from whence the object diffusing them is visible . notwithstanding this , we shall so farr comply with the vulgar doctrine , as to allow ; that in respect even of one single eye , in whatever part of the medium posited , the diffusion of rayes from an object may be affirmed to be sphaerical : insomuch as no part in the object at considerable distance singly discernable , can be assigned , which is not less than the pupil of the eye . ( ) that the light diffused through the medium , is not seen by us : but that thing beyond the medium from which some rayes are ultimately reflected into the eye . for , if it chance that we persuade our selves , that we perceive something in the medium ; it is not pure light it self , but some crass substance , the small particles of dust , vapours , smoak , or the like , which having received light from some luminous source , reflect the same toward the eye . sect . ii. now , of all these praeconsiderables only the first can be judged praecarious , by those whose festination or inadvertency hath not given them leave to observe the certitude thereof inseparably connected to the evidence of all the others , by the linkes of genuine consequence . and therefore , that we may not be wanting to them , or our selves , in a matter of so much importance , as the full confirmation of it by nervous and apodictical reasons ; especially when the determination of that eminent and and long-lived controversie concerning the quiddity or entity of light , whether it be an accident , or substance , a meer quality , or a perfect body ? seems the most proper and desiderated subject of our praesent speculations , and the whole theory of all other sensible qualities ( as vulgar philosophy calls them ) is dependent on that one cardinal pin , since light is the nearest allied to spiritual natures of all others , and so the most likely to be incorporeal : we must devote this short section to the perspicuous eviction of the corporiety of light. not to insist upon the grave authority either of empedocles , who , as aristotle ( . de sensu & sensili : & de gener. animal . . cap. . ) testifieth , affirmed light to be 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , effluxionem , a material emanation , and required certain proportionate pores , or most slender passages in all diaphanous bodies , for their transition ; or plato , who defined colour , or light disguised , to be 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ef●luentem quandam flammulam ; or of democritus and epicurus , both which are well known to have been grand patrons , if not the authors of that opinion , that light is corporeal : we judge it alone sufficient to demonstrate the corporiety of light , that the attributes thereof are such , as cannot justly be adscribed to any but a corporeal entity . such are ( ) locomotion ; for manifest it is , that some substance , though most tenuious , is deradiated from every lucidum to the eye of the distant spectator : nor is a bullet sent from the mouth of a full charged cannon with the millionth part of such velocity , as are the arrows shot from the bow of apollo ; since the rayes of the sun are transformed from one end of the heavens to the other , in a far less division of time , than a cannon bullet is flying to its m●●k . ( ) resilition ; for the rayes of light are sensibly repercussed from all solid bodies , on which they are projected ; and that with such pernicity or rapid motion , as transcends , by inassignable excesses , the rebound of a cannon ball from a rock of adamant . ( ) refraction , for our sense confirms , that light is ever refracted by those bodies , which allow its rayes a passage , or through-fare , but not an absolute free and direct one . ( ) coition , or union , or corroboration , from bodies either reflecting , or transmitting many rayes to one common point of concurse , where they become so violent as to burn any thing applied . ( ) disgregation and debilitation , from the didaction of its rayes reflected or trajected : so that those which before during their union were so vigorous as to cause a conflagration , being one distracted become so languid as not to warm . ( ) igniety ; since light seems to be both the subject , and vehicle to heat , and those speak incorrigibly , who call light , flame attenuated . which we shall less doubt , if we consider the natural parallelism betwixt flame and water , light and a vapour . for , as water by rarefaction , or attenuation becomes a vapour ; so may we conceive flame by attenuation to become light circumfused in the aer : and as a vapour is nothing else but water so rarefied into small discontinued particles , as that it doth scarce moisten the body on which it is impacted ; so is light nothing else but flame so dilated by rarefaction , that it doth hardly warm the body it toucheth . lastly , as a vapour how finely soever rarefied , is still substantially water ; because only by the coition of its dif●used particles it returns again to water , as in all distillations : so must we account light however rarefied , to be still substantially flame ; because only by the coition , or congregation of its dispersed rayes it is reducible into absolute flame , as in all burning-glasses . these attributes of light considered , it is not easie for the most praevaricate judgment not to confess , that light is a corporeal substance , and the rayes of it most tenuious streams of subtle bodies : since it is impossible they should be deradiated from the lucid fountain with such ineffable pernicity , transmitted through the diaphanum in a moment , impacted against solid bodies , repercussed , corroborated by unition , debilitated by disgregation , &c. without essential corpulency . notwithstanding this apodictical evidence of the corporiety of ligh● , the refractary peripatetick will have it to be a meer quality , and objects ( ) that his master aristotle , impugning the doctrine of democritus , epicurus , and others , who ascribed materiality to light , defined it to be meerly 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 perspicui , an act of the perspicuum . to this we answer , ( ) that though aristotle thought it sufficient barely to deny that light is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ullius corporis ef●luxum , and to affirm it to be energian perspicui , ut perspicuum ; yet will the judicious discover it to be rather an ambage to circumvent the incircumspect , than a demonstration to satisfie the curious . for , though philopouus ( . de anim. . ) willing to conceal or guild over his masters error , interpreteth his perspicuum actu , or illustrate nature , and so light to be a kind of chord , which being continuedly interposed betwixt the object and the eye , causeth that the colour thereof posited beyond the medium , doth affect and move the eye to the act of intuition : yet hath he left the reason and manner of this supposed act of the perspicuum on the eye , the chief thing necessary to satisfaction , involved in so many and great difficulties , as proclaim it to be absolutely inexplicable . ( ) that albeit we deny not illumination to be meerly ●cc●dental to opace bodies ; yet therefore to allow the light , wherewith they are illuminate , to be an accident , and no substance , is a manifest alogie . and to affirm , that the aer , water , or any diaphanous body is the subject of inhaesion to light , is evidently incongruous ; because every medium is simply passive , and remains unmoved while the light pervades it : and how can light pervade it , if it be not corporeal ? or how can the rayes thereof conserve their tensity and directness in the aer , while it is variously agitated by wind and other causes , if they were not absolutely independent thereupon ? ( ) what aristotle saith concerning the propagation of the species of light even to infinity in all points of the medium , besides its incomprehensibility , is absolut●ly inconsistent to the pernicity of its motion , which is too rapid and momentany to proceed from a fresh creation of light in every point of the medium : since the multitude of fresh productions successively made , would r●quire a far longer time for the transmission of the light of a candle to the eye of a man at the distance of but one yard , than our sense demonstrates to be necessary to the transmission of the light of the sun from one end of heaven to the other . ( ) that by allowing light to be corporeal , we incurr the absurd●ty of admitting two bodies into one and the same place . which is soon solved by reflecting on what we have formerly and frequently said , concerning inanity interspersed , and observing what we shall ( god willing ) say of those eminent qualities , rarity and perspicuity : from either of which it may be collected , how great a multitude of pores are in every rare and perspicuous body , which remain tenantable , or unpossessed . ( ) that from the corporiety of light it must follow , that a body ma● be moved in an instant . but he hath not yet proved that the motion of light is instantaneous : and we have , that it is not , but only momentany , i. e. that ligh● is moved in a certain space of time , though imperceptible , yet divisible , and not in one individual point , or instant . ( ) that the rayes of light are invisible in pure aer , and by consequence immaterial . solut. their invisibility doth not necessitate their immateriality ; for the wind , which no man denies to be corporeal , is invisible : and as it sufficeth that we feel the wind in its progress through the aer , so also is it sufficient that we perceive light , in the illumination of opace bodies , on which it is impinged , and from which it is reflected . besides , whoso maketh his sense the measure of corporiety , doth strain it to a higher subtility , than the constitution of its organs will bear , and make many more spiritual entities , than can be found in the universe ; nay , he implicitely supposeth an immaterial being naturally capable of incorporation meerly by the unition of its dispersed particles ; since many rayes of light congregated into one stream become visible . ( ) that the materiality of light is repugnant to the duration of the sun ; which could not have lasted so long , but must have , like a tapour , exhausted its whole stock of luminous matter , and wincked out into perpetual night , long since , if all its rayes were substantial emanations , according to our assumption . but this refuge may be battered with either of these two shots . the superlative tenuity of the luminous particles continu●lly emitted from the body of the sun , is such as to prevent any sensible minoration of its orb , in many yeers . ( ) if the diametre of the sun were minorated by miles less than it was observed in the days of ptolomy ; yet would not that so vast decrement be sensible to our sight : since being in its apogaeum , in summer , it doth not appear one minute less in diameter to the strictest astronomical observation , than in winter , in its perigaeum , and yet snellius , bullialdus , and gassendus , three astronomers of the highest form , assure us that it is about miles more remote from us , in its apogaeum , than perigaeum . ( and lastly ) that if light were flame , then would all light warm at least : but there are many lights actually cold , such as that in the phospher m●neralis , or lapis phenggites , of whose admirable faculty of imbibing , retaining and emitting a considerable light , the excellent fortunius licetus hath written a singular tract , and athanas. kircherus a large chapter ( in art. magn . lucis & umbrae lib. ● . part . . cap. . ) , in gloworms , the scales and shells of some fishes , among which the most eminent are those dactyli mentioned by kircher ( in libri jam citati part . . cap. . ) in these words , sunt & dactyli , ostreacei generis , qui vel manibus triti lumen veluti scintillas quasdam ex se spargunt : quemadmodum melitae , in sicilia , calabria , & ligustici maris oris non sine admiratione à piscatoribus & nautis instructoribus observasse memini ; in rotten wood , &c. ergo , &c. answer , the defect of actual heat in these things , doth arise , in part from the abundant commistion of gross and viscid humidity with those igneous particles that are collucent in them ; but mostly from the exceeding rarety of those luminous sparks : which being so thin and languid , as to disappear even at the approach of a secondary light , cannot be expected vigorous enough to infuse an actual warmth into the hand that toucheth them ; especially when experience attesteth , that the rayes of the sun , after two reflections , become so languid by attenuation , as they can hardly affect the tenderest hand with any sensible heat . and therefore , unless it can be evinced , that the disgregation of the parts of a body , doth destroy the corporiety of it ; and that the simple attenuation of lig●t doth make it to be no light : we ask leave to retain our p●rsuasion , that the existence of many lights , which are devoyd of heat , as to the perception of our sense , is no good argument against the igniety and corporiety of light. chap. vi. the nature of a sound . sect . i. it was a hypochondriack conceit of plato , that all our cognition is but recognition , and our acquired inte●lection a meer reminiscence of those primitive lessons the soul had forgotten since her transmission from the sphere of supreme intelligences , and immersion into the opacity of flesh. for , proper science is proper only to omniscience ; and not to have knowledge by infusion or acquisition , is the attribute only of the essence of wisdom ; and a priviledge due to none but the ancient of dayes , to have his knowledge derived beyond antiquity : but man , poor ignorant thing , sent to school in the world , on the design of sapience , must sweat in the exploration and pursuit of each single verity ; nor can he ever possess any science , in this dark region of life , but what he hath dearly purchased with his own anxious discovery , or holds by inhaeritance from the charitable industry of his fore-fathers . and , that the naked mind of m●n , endowed only with a simple capacity of science , might by degrees adorn it self with the notions of whatever concerns his well-being either in this state of mortality , or that future one of immortality ▪ hath the bounty of his creator furnished him with the sense of hearing : a sense particularly and eminently ordained for discipline . for , though we sing hymns to the eye , for the invention : yet must we acknowledge a sacrifice of gratitude due to the ear , for the communication and diffusi●n of arts and sciences . quemadmodum aspectus ad vi●ae dulcedinem , & ●ommoda ●st magis necessarius : ita auditus ad excipiendam artem , scientiam ▪ & sapientiam est accommodatior : ille ad inventionem , hic ad communicationem aptior est ; saith that accurate and eloquent anatomist , iulius casserius placentinus , ( in premio ad libr. de sens . organ . ) . thus much the antique aegyptians intimated in their hieroglyphick of memory , the figure of a mans ear ; and the philosopher exprest in his character of the hearing , auditus est sensus disciplinae ; as also that modern ornament of germany , sennertus ( in hypomn . phys. ) in this memorable sentence ; aures in homine quasi porta mentis sunt , per quam illi communicantur , quae doctrina & institutione de deo , & alijs rebus necessarijs traduntur , quaeque nullo alio sensu addisci possunt . now , to bring you home to the scope of this ( not otherwise or unreasonable , or unnecessary ) elogy of the hearing ; since the relation betwixt the sight and hearing is so great , as to the point of mans acquisition of knowledge , as that the one can be no more justly called the discoverer , than the other the propagator of all arts and sciences : it is evident we have made no undecent knot in the clue of our method , by immediately subnecting this enquiry into the nature of a sound , the adaequate and proper object of the hearing , to our praecedent speculations of the nature of vision , colours , and light. besides , as these two senses are cousin-germans , in their uses and ends : so likewise are they of near alliance , in their objects ; there being no small , nor obscure analogy , betwixt the nature and proprieties of a visible species , and the nature and proprieties of an audible species , or sound . for ( ) as ●t is the property of light , transfigured into colours , to represent the different conditions or qualities of bodies in their superficial parts , according to the different modification and direction of its rayes , either simply or frequently reflexed from them , through the aer , to the eye : so is it the propriety of sounds to represent the different conditions or qualities of bodies , by the mediation of the aer percussed and broken by their violent superficial impaction , or collision , and configurate into swarms of small consimilar masses , accommodable to the ear. so that he speaks as philosophically , who saith ; that various sounds are no more but the various percussions and imprest motions of the aer : as he that saith , colours are no more then the various immersions of light into the superficial particles of bodies and respective emersions or reflections from them , through the diaphanous medium to the eye . nor can we much dislike the conceipt of athanas kircher . ( musurgiae universalis l. . part . . praelus . . ) that if it were possible for a man to see those subtle motions of the aer , caused by the strings of an instrument , harmonically playd upon ( as we may the circular undulations , and tremblings of water , raised by a stone thrown into it , in a river or standing lake ) the whole tune would appear to him like a well drawn picture , ingeniously and regularly adumbrate with admirable variety of colours , each one distinctly representing the particular condition of that string or sonant body , that created it . ( ) as light immediately fails and disappears upon the remove or eclipse of its lucid fountain ; as is manifest by the succession of darkness in a room at night , when a candle is either removed out of it or extinguished , the succession of its rayes being intercepted : so doth a sound instantly perish upon the cessation of the undulous motion of the aer , which conduceth not only to the creation , but delation of it , as the principal , if not the sole vehicle . for , the subsistence of sounds is not by way of dependence upon the solid bodies , by which they were produced ; according to the proposit. of mersennus ( harmon . lib. . pag. . ) soni non pendent à corpore , à quo primum producti sunt : but upon the continuation of the motion imprest upon the aer , so that the duration of a sound is equal to the duration of the agitation of the aer . and therefore bapt. porta , cornelius agrippa , wecherus , alexius , and others of the same tribe , that so highly pretend to phonocamptical magick , are worthy more than derision , for their insolent undertaking to conserve a voice , or articulate sound of many syllables , by including it in a long canale of lead , or other impervious matter ; so that upon unstopping the extreme of the tube , after many not only hours , but months , the voice shall issue out as quick and distinct as at the first pronunciation , or insusurration into the cavity thereof . which ( whether more impudent , or ignorant ( for both experience and the nature of a sound evidence the contrary ) is disputable ) rhodomantade is demonstrated to be absolutely impossible , by athanas. kircher . ( musurgiae universal . lib. . & magiae echotectonicae cap. . ) whether we remit the unsatisfied . ( ) as the actinobolism , or deradiation of light from the luminary , is sphaerical , in respect of the circumambient space illuminate by it : so is the diffusion of a sound in excentral lines from the sonorous body , through the whole space , or medium within the sphere of its vertue ; for , otherwise a general , speaking in the midst of his army , could not be heard in round . here is the only difference betwixt the actinobolism of light and sounds ; that the one is performe● in time imperceptible , though not instantaneous : the other in moments distinguishable , which are more or less according to the degrees of distance betwixt the sonant and audient . again , as the deradiation of light , considered meerly as visible , not as lucidum , is conical , or pyramidal , in respect to the eye of the spectator ; as we have professedly demonstrated in the . article of the . sect. of our chapt. concerning the nature of light : so likewise doth every sound make a cone , or pyramid in the medium , whose base consisteth in the extreme of the body producing the sound , and cone in the ear of him that hears it ; or as some mathematicians , as blancanus and mersennus , whose base is in the ear , and cone in some one point of the sonorous subject . allowing only this difference ; that the cones or pyramids of visible species are more geometrical , i. e. more exactly conform to proportion geometrical , than those of audible species ; which in regard as well of the grossness of their particles , as less velocity of their motion , are easily injured and perturbed by winds . and this , in truth , is the best ground they have to stand upon , who opinion sounds to be no more but simple motions of the aer . ( ) as visible species , so do sounds inform the sense , of the magnitude , figure , and other qualities of the bodies , from which they are emitted . for experience assureth , that greater bodies emit a graver sound , than smaller ; that concaves yeild a stronger and more lasting sound , than planes ; that hard things sound more acutely than soft ; strings distended yeild a sharper sound , than lax ; empty vessels than full , &c. hence is it , that goldsmiths , and coyners distinguish good mony from bad , pure gold from that largely allayed with copper ; and metallists judge of simple and compound metals , only by their ring or sound . and we have heard of vintners , who could exactly distinguish the kinds and goodness of wines , only by the sound of the vessels that contained them : and therefore used to choose them more by their ear , than palate . but , what we here say , that harder bodies emit a sound more acute than softer ; we desire may be understood only of the plurality , not generality of bodies . for the examining mersennus , having experimented the different sounds of metalls , tells us ( in praefat . ad harmonic . ) that he found a cylindre of iron to be unisone to another of steel , equal in diametre and length ; and both in acuteness to transcend a cylindre of brass of equal dimensions , by a whole diatessaron : nay more , that a cylindre of firr wood yeilded , upon equal percussion , a sound more acute by a whole ditone , than a cylindre of brass , which yet yeilds a sound more strong , lasting and grateful than any of the rest . each of which observations is sufficient to cut off the general intaile of that canon , sonos eò acutiores , quo duriora fuerint corpora . legendus est athanas. kircher . art. magn. consoni & dissoni lib. . appendice de phonognomia . ( ) as a greater light alwayes obumbrates a less , so a great sound alwayes drowns a less : for it is manifest , that the sound of a trumpet conjoyned to the low or submissive voice of a man , makes it wholly unaudible , and the loud clamours of mariners are scarce heard in a tempest . ( ) as a too great light offends alwayes , and often destroyes the sight , as is eminently exemplified in the tyranny of dionysius , the sicilian : so , too great sounds injure and lacerate the hearing . for , many men have been strucken deaf for ever , by great thunder-claps , and as many by the reports of grand artillery . ( ) as light , meerly by the condensation of it rayes , produceth heat in the aer : so sounds meerly by their multiplication . for , it is observed , that in all battails , and chiefly in naval fights , where many cannons are frequently discharged , the aer becomes soultry and hot ; not so much from the many sulphureous or igneous particles of the gunpowder commixt with , as the violent concussions , and almost continued agitation of the aer . so that even in this particular , that axiom , that motion is the mother of heat , holds exactly sound . ( ) the effects of audible species , as well as of visible , are subject to variation , according to the divers condition of the medium . for , as flame , beheld through smoak , seems to tremble : so do sounds , trajected through aer variously waved by winds , rise and fall betwixt every gust ; as is observable most easily in the ringing of bells , whether the wind be favourable , or adverse . ( ) and what most conduceth to our comprehension of the nature of a sound ; for , as light , so is a sound capable of locomotion , exsilition , impaction , resilition , disgregation , congregation ; all which are the proper and incommunicable attributes of corporiety . only we must confess them discrepant in this , ( ) that sounds are delated from their original not only in direct lines , but circular , elliptical , parabolical , and all others ; for a sound heard on the other side of a high wall , comes not to the ear in a direct line through the wall , as kircherus contends ( in musurgiae universal . lib. . ) with taedious arguments , but in an arch , as the incomparable st. alban hath firmly evinced ( in cent. . natural . hist. ) : whereas light constantly progress through the medium to the eye , in direct lines , whether primary , reflex , or refracted . ( ) a sound is diffused through it sphere of activity in a longer space of time , by much , than light , as is sensibly demonstrated by this , that the flash of a cannon arrives much sooner at the eye , than the report at the ear : and the immediate reason hereof is the less velocity of motion in the sound , which consisting of grosser particles than those of light , must be proportionately slower in its delation . for , a sound seems to be nought but the aer , at least the subtler or more aethereal part of aer , extrite and formed into many small ( moleculae ) masses , or innumerable minute contextures , exactly consimilar in figure , and capable of affecting the organ of hearing in one and the same manner : which configurated small masses of aer fly off from bodies compulsed or knockt each against other , with some violence ; and progress by diffusion in round . for , because upon pressure they mutually recede , each particle going off in that point where it finds the freest egress : therefore must some tend upward , others downward , some to the right , others to the left , some obliquely , others transversly , &c. but all more slowly than the particles of light , whose tenuity being far greater , causeth them not to be subject to retardment by the like tumultuous convolution . but , as the greater corporiety of sounds makes them slower in their diffusion ; so doth it make them more impetuous and forcible in their impaction , than the species of light : it being obvious to observation , that violent sounds , such as great thunders , volleys of cannon shot , the breaking of granades , &c. usually shake the largest buildings , and shiver glass windows at a mile distance and more . and yet are sounds far easilier impeded , perturbed , and flatted , than the rayes of light ; every man knowing that no sound can penetrate glass , but in one case , or exigent of nature , of which we shall particularly speak , in the last section of this chapter : and since sounds are repercussed more slowly ; they 〈◊〉 disgregated more hardly , and congregated more faintly , than the rayes of light. lastly , the proportion of retardation in the diffusion of sounds to the utmost of their sphere of activity , is such even from winds ; that as mersennus hath computed , the diameter of the sphere of a sound , heard against the wind , is by almost a third part less than the diameter of the sphere of the same sound , assisted by a favourable or secund wind : but the diameter of a lucid sphere is alwayes equ●● , which way soever and how violently soever the wind blows . ( ) bodies of narrow dimensions make a sensible reflection of light ; as is manifest from a burning-glass of an inch diameter : but a body of far greater dimensions is required to the sensible reflection of a sound , i. e. to the production of an eccho ; though it is not to be doubted , but ●●ound may be reflected from every hard bodie on which it is impinged . this considered , we cannot but smile at the credulity of many grea● aristoteleans , who are persuaded that an echo is made by the meer repercussion of the sound from the particles of the aer . for , notwithstanding we deny not , but the particles of the aer , within the sphere of the sounds diffusion , encountring and arietating those particles of the sound , may in some small measure repercuss them : yet we think it unsafe , therefore to admit this aereal repercussion to arise to sensibility , or to be observable by the creation of an echo . and therefore we conceive , that whatever sensible reflection or multiplication of a sound , seems to proceed from the aer , is not caused really by the aer , but some dense and hard bodies , such as rocks , aedifices , arches , &c. whose concavities reflect the particles of a sound for the same reason , that concaves multiply light. sect . ii. the congruities of visible and audible species being so many and essential , and their incongruities , or points of discrepancy so few , and those altogether consisting in the meer degrees of velocity , and some other circumstances relating to the medium : we have a fair and direct way opened to our enquiry into the quiddity or essence of a sound . wherefore since to conclude a parity of essence , from a parity of attributes and effects , in any two entities ; is warrantable even by the strictest laws of reasoning : we shall adventure to assume a sound to be a corporeal ens. which before we farther confirm by arguments , it behoveth us to lift that block of contrary authority out of our readers way , at which the credulity and incircumspection of many have made them stumble and hault ever after in their opinions concerning this subject . true it is , that pythagoras , plato , and aristotle , according to the memorials of plutarch ( . placit . . ) unanimously held a sound to be incorporeal , a meer accident , or quality , or intentional species ; contrary to the doctrine of democritus , epicurus and the stoicks , who , as laertius ( in lib ▪ . ) expresly records , affirmed it to be corporeal , or a material efflux , the words of epicurus being [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] vocem seu sonum , fluxum esse em●ssum ex rebus aut loquentibus , aut sonantibus , aut quomodocunque strepitum edentibus . but yet we conceive this repugnancy of authority insufficient to infirm our thesis of the corporiety of sounds ; as well because simple authority , though never so reverend , is no demonstration , and scarce a good argument , in points physiological , where the appeal lies only to reason : as for this weighty consideration , that these accepted a sound in concreto , i. e. for the substance of the aer , or its most tenuious particles , together with their proper configuration ; but those in abstracto , or only for the figure imprest upon the superfice of the aer , which they therefore inferred to be incorporeal , that is , devoyd of profundity . for , otherwise plato ( apud agellium , lib. . cap. . ) defines a sound acris validaque aeris percussio , a smart and strong percussion of the aer : and aristotle ( . de anim. cap. . ) calls it downright a motion of the aer , as the stoicks , ictus aeris ; a stroke of the aer . so that the difference seems occasioned only by their diverse acceptation of the word sound . this obstruction removed , we progress to the discharge of our province , viz. the eviction of the corporiety of a sound . the first argument of the corporiety of a sound , is ( quod vim habet agendi , sive efficiendi aliquid ) that it is active or effective . for , the voice of a man violently emitted , or highly elevated by a kind of grating offends the vocal organs , and changes their sweetness or evenness into a hoarsness ; and being long continued , leaves them misaffected with lassitude : as the experience of hunters and orators demonstrates . hither are we to referr lucretius his praeter radit enim vox fauces saepe , facitque , asperiora foras gradiens arteria clamor , &c. the second is desumed from its capacity of repercussion , or resilition from solid bodies ; which is the evident cause of our hearing one sound twice , or more often , according to the multiplicity of its reflections : as in all echoes , monophone or polyphone . which aristotle fitly compares not only to a ball frequently rebounding , but also to light , which himself confesseth capable of reflections even to infinity : thereon concluding a sound subject to the same laws of reflection with either . to which virgil seems to allude in his saxa sonant , vocisque offensa resultat imago . intimating , that an echo holds a perfect analogy with an image reflected from a mirrour . for , as beside that image , which tends in a direct line from the glass to the eye , innumerable others are so transferred from it into all point● of the medium , that divers other eyes variously posited therein shall behold the same general image , each one receiving a particular image : so likewise , beside that sound or voice , which arrives at your ear , innumerable others are so dispersed through all parts of the medium or sphere of diffusion , that if there were as many ears therein as the space could contain ▪ each one would hear the same general sound or voice ; and if it chance that any one particular voice be impinged against solid and laevigated or smooth bodies ( for solids that are very spungy or porous , suffer sounds to pass through them , and too scabrous or rough destroy them by dissipation ) it may be repulsed in a direct line toward your ear , and you shall hear it again at second hand or echoed . touching the reflection of sounds , we shall here , by way of corollary , brie●●● observe . that in case you stand somewhat near to the smooth solid 〈◊〉 reflecteth the sound , and the creation of the sound be not very 〈◊〉 ; then though an ec●o thereof be made , yet shall not you hear it ▪ because the direct sound and the reflex enter the ear so continently ▪ 〈◊〉 the space of time betwixt their ingress is so imperceptible , that 〈◊〉 seem but one intire sound . but , in this case , the sound becom●● both stronger and longer ; in respect of their union . and this comes to pass chiefly , when the reflection is made from divers bodies at once ; as in all arches , and concamerated or vaulted rooms : in which for the most part , the sound or voyce loseth its distinctness , and degenerates into a kind of long confused bombe . and hence , viz. the many repercussions of a sound from divers places together , or with so short intervals of time , as the sense cannot distinguish them ; is it , that the sound of concaves percussed , lasteth much longer , than the sounds of bodies of any other figure whatever : especially when the concave hangs at liberty , in the aer , so that its tremulation be not hindred as are all bells in churches , and clocks . for , not only the external or ambient aer , but the internal is agitated by those frequent tremblings in the body of the concave , and continuedly repercussed from side to side : and therefore , till the trembling ceaseth , the bombination is continued . again , if you stand far from the sonant bodie , and near to the reflectent ; in this case also will the sound appear single , and coming only from the reflectent : because both the direct and reflex sound invade the ear without any sensible difference in time ; and yet the reflex sound as it is really the posterior , so doth it very much intend or increase the direct , and consequently makes the impression observable only from it self . it is observable moreover , that by how much nearer the ear is to the anacamptick , or reflectent ( yet at such distance , as is required to the discernment of the direct voyce from the reflex . ) by so much the fewer syllables of a word pronounced are echoed : and è contra , by how much farther from the reflectent ( provided the distance exceed not the sphere of diffusion ) so many more syllables are repeated . the reason being this , that the interval of time betwixt the cessation of the speaker , and the audition of the reflex voice , is much less in the first case , and much greater in the later : and consequently , the less interval of time sufficeth to the distinction of a fewer syllables , and the greater for more . this considered , we can no longer admite the distinct rehearsal of a whole hexameter by some strong echoes ; provided the voice pronouncing the verse be sufficiently strong to drive it to the reflectent , and thence back again to the ear , at large distance , such as is necessary to the allowance of time enough for the successive repercussion of each syllable : for otherwise the voice faileth by the way . what hath been hitherto said , concerns only echoes monophone , that repeat the same syllable but once ; but there are echoes polyphone , such as repeat one and the same note , or syllable divers times over , and of them the reason is far otherwise . for , the frequent rehearsal of the same syllable by an echo , ariseth from the multitude of reflectent bodies , situate beyond each other in such order , that the nearer bodies referr it first , and the remoter successively : and sometimes from bodies mutually confronting each other , and alternately reflecting the same sound . of this sort were those observed by lucretius , in this tristich . sex etiam , aut septem loca vidi reddere voces , unam cum jaceres ; ita colles collibus ipsis verba repulsantes , iterabant dicta referre . such also was that prodigious one that entertained the curiosity of gassendus at pont charenton standing upon the river seine , four miles from paris . for in a square old aedifice of free-stone , uncovered at the top , and having a row of pillars on each side , as commonly our churches , he heard a monosyllable , which himself pronounced , clearly and orderly repeated by several echoes , times over ; and when he uttered the monosyllable in the centre of the aedifice , it was brought back to his ear times from each extream ( the area being somewhat oblong ) so distinctly , as he could easily numerate the repetitions on his fingers . if so sileat miracula memphis , let the aegyptian pyramids no longer boast their pentaphone echoes ; nor the porticus olympiae challenge the garland from the world for her heptaphone resonance , which is highly celebrated by the pens of plutarch ( lib. . de placit . philosoph . cap. . ) and pliny , ( lib. . cap. . ) . for , this at pont charenton , of which our lord st. alban was also an ear-witness , and not without some admiration , as himself hath recorded ( in centur. . nat. hist. ) hath no rival , but that many tongued echo in a village called simoneta , near millan in italy , which at some seasons , when the aer is serene , will iterate any monosyllable , in which is no s. ( which being but a kind of sibilation , or interior sound , few or no echoes can reherse ) times over very distinctly ; if credit be due to the testimony of blancanus ( in echometria , & in suo additione ad theorem . . de echo polyphona ) a third argument of the materiality of a sound , results to us from the pleasure and offence , or gratefulness and ingratefulness of sounds , as they are concinnous , or inconcinnous . for it is highly concordant to truth , that the suavity of a sound proceeds from hence , that those minute particles , which enter the ear and move the auditory nerve , are in their configuration so accommodate to the receptaries , or pores thereof , that they make a gentle , smooth or equal impression on the filaments , of which the acoustick nerve consisteth : and on the contrary , the acerbity , or harshness of a sound , only from hence , that the minute particles invading the sensory , being asper or rough in their configuration , in a manner exulcerate , grate , or dilacerate the slender filaments thereof . that a certain configuration of its minute particles , is essentially necessary to every sound , may be concluded safely even from hence ; that so great variety of sounds , and chiefly of words , or letters , as well vowels as consonants , could not be so exactly distinguished by the hearing , unless the sensory were variously , or in a peculiar manner percelled and affected by each : nor can that variety of affection be made out , but by a variety of sigillation , or impression , dependent respectively on the various configuration of those ( moleculae ) small masses , that compose the sound . to sweeten the harshness of this assertion yet more ; we alledge the unison auctority of no less than pythagoras ( whom all knowing men allow to have lighted the tapour to posterity , in the investigation of the nature , and causes of proportions among musical sounds ) plato and aristotle , all which affirmed the same , if plutarch be faithful ( in . de placit . ) while he introduceth them saying , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , figuram , quae in aere , ejusque superficie fit certo ex ictu ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) evadere vocem , that the figure made in the aer , and then it superfice , by some certain percussion , becomes a voice . and , that plutarch hath done no more than justice to aristotle , in this particular ; is evident from his own words , ( in problem . . & . ) where he expresly enquires , quare vox , cum sit 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , aer quidam figuratus , & qui dum transfertur , plerumque , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , figurum amittit , illam tamen dum a solido corpore repercutitur , incolumem servet ? why a voice , which is aer configurate , and for the most part loseth its figure , in its [ long ] transmission , doth yet conserve it intire and unimpaired , when repercussed from a solid body , as in all echoes ? nor can it be rightly denied , but that flux of minute aereal bodies , or most aethereal parts of the aer , which are excussed in round by two bodies arietating , are easily capable of configuration : when as much is subindicated even by those sensible vortices , or whirlings and eddies of winds , which are frequent in summer . under this title fall those words of epicurus , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , &c. hunc vero fluxum in frustula consimilis figurae comminui : the full sense whereof seems to be this . that whem a voyce is emitted from the mouth , or other sound from what body soever ; the contexture of the minute bodies effluent is so comprest , and confracted into smaller contextures , that of the original are made swarms of copies , or lesser masses exactly consimular in their formation : and that those are instantly dispersed sphaerically , or in round through the whole circumfused space , still conserving their similitude to the original , or general voyce , or sound , till their arrival at the eare ; and so retaining the determinate signature of their formation , are distinguisht accordingly by the sensory . by this it appears , that epicurus , in this point , dissented inconciliably from democritus ; who conceived that all sounds were delated to the ear by propagation , i. e. that the sound being broken into myriads of small fragments , each fragment did form the contiguous aer into contextures of the same configuration with the prototype , and those again formed the particles of aer next adjacent into the like , and so successively through all parts of the medium till they came home to the organ of hearing ; not much unlike the dream of the aristoteleans , concerning the propagation of the species of light in each point of the medium . whereas the conception of epicurus is this , that the primitive configuration of the most tenuious particles of the aer , by the percussion or collision , is broken into many small masses ; and each of those , at farther remove from the sonant into many smaller , and those again into smaller , all exactly respondent to the first in figure : after the same manner , as we observe a spark of fire exsilient from a firebrand , to be broken into a multitude of less sparks , and each of those shivered again into many less , until their exility makes them totally disappear . this reason and manner of the diffusion of a sound throughout so great a space of the medium , they may easily comprehend , wh● have observed the sewers of princes in italy spout orang-flower water , or other fragrant liquors , out of their mouths , with such dextrous violence , as to disperse it in a kinde of mist , through the aer of a spacious room , so that the aer contained therein becomes impraegnate with the odour , for the more noble entertainment of the sense . for the consent betwixt this exsufflation of water , and the spherical diffusion of a sound , is very manifest , the greater drops of water being in their trajection through the aer , broken , by reason of the impulse of the breath , that discharged them in distress , into swarms of less drops , and those again into less , successively in the several degrees of remove , until they attain such exig●ity , as we observe in the particles of a mist : and that small proportion of aer , emitted from the mouth of him that speaks , being dispersed into a dense mist of voyces , replenishing the whole sphere of diffusion . here we are constrained to a cautionary advertisement ; that when we say , the aer is the material of all voyces , we do not mean all the breath expired from the lungs , together with those fuliginous exhalations , that the densation of the aer , in cold weather , subjects to the discernment of our sight ; but onely the most subtle part of the aer inspired , and modulated in the vocal artery and other organs of speech : because such onely can be judged capable of configuration . nor can so small a quantity of purest aer be thought insufficient upon dispersion to possess so capacious a sphere , as that of every ordinary voice ; so that of a whole theatre of auditors , each one shall distinctly hear it : insomuch as onely a mouthful of water blown from a fullers mouth , is so diffused as to irrigate the aer replenishing a room of considerable amplitude . especially , when the analogy holds quite through . for , as the drops of water are so much both larger and denser , by how much neerer they are after exsufflation to the mouth of the fuller : so also are the vocal masses of aer so much more large and dense or agminous , by how much neerer they are to the mouth of the speaker ; and ● contra . which alone is the reason , why the voyce of an or●tor in a theatre is more strong and distinct to those of his auditory , that sit neer at hand , than to those far off ; provided the place afford no concurrent eccho , for in that case , the reflex voyce entering the eare united with the direct or original , magnifies the impression on the sensory . now , insomuch as it is consentaneous to right reason , to conceive , that the voice at●t first emission from the mouth , it s one general configuration of the mos●●nuious particles of the aer , with some vehemency efflated from the 〈◊〉 organs , after frequent collisions and tremulous repercussions , and that this general voice , in its diffusion through the medium , is c●ntracted 〈◊〉 dispersed into myriads of minute vocal configurations or particular voyces , some of which invade the ears of one person , others of another , &c. hence is it a clear , though perhaps new and very paradoxical , truth ▪ that the same numerical voyce of an orator , is not heard by any two of his auditors , nay not by the ears of any one ; but every man , and every eare is affe●●ed with a distinct voyce . and yet he incurrs no contradiction , that affirms the whole auditory to receive the same voyce . for , as all the water exsufflated into a mist from the mouth of an italian sewer , or common fuller , may be said to be one and the same water ; though all the minute drops , diffused into several parts of the aer , and irrigating the several parts of the floor or cloth , on which they 〈◊〉 rained down , be not the same drops : so likewise may we allow all the aer efflated from the mouth of the speaker , to be one and the same aer ; though the particular voyces , delated to particular ears , are not the same numerically . besides , should we , with the major part of scholers , admit a voice to be an entity meerly intentional , or simple quality , or accident , yet should we not detract one grain of weight from this our paradox : since , to conceive any one particular voice to be in divers places , or subjects , at once , is manifestly absurd . here opportunity would prompt us to insist upon the admirable conformation of an articulate sound , and to enquire how each vowel and consonant is created by such and such motions of the vocal instruments : but the exceeding difficulty countermands that inclination . for , though casserius , placentinus , ( in anatom sirmorin . organ . ) & athanasius kircherus ( in lib. anatomico de natura sonis & vocis , à cap. . ad finem libri . ) have attempted laudably in that abstruse theme : yet the audit of their discoveries riseth no higher than this single rule , that the vocal artery and lungs onely conduce to the acuteness and gravity of the voice , as they discharge the inspired aer more pressly , or laxly ; and kircher ( in cap. . ) ingenuously confesseth , at quomodo voces in gutture formentur , qua proportione elisionis aeris nascantur , tam obscurum est , quam voces hujusmodiclarae sunt & manifestae auditui . the difficulty , indeed , seems to consist chiefly in this , how from the various motions of one single organ , the tongue ( the author of distinction in all articulate sounds , though the palate , epiglottis , uvula and teeth are in their respective degrees of assistance inservient to the elision of aer made by the tongue ) and that two-leafd door of the mouth , the lips , such infinite variety of letters and words doth most easily and almost insensibly result . to solve this , the general answer is , that the wonder ought to be no greater , how one tongue can suffice to the articulation or distinction of innumerable words , by its various motions ; than that , how one hand sufficeth to the distinction of innumerable characters . but , the motions of the hand requisite to distinction of every character , are observable by the sense : and those of the tongue and lipps requisite to the formation of every word , together with the proportion of the aers elision in every articulation , is deeply obscure : and therefore the disparity being manifest , the problem remains untoucht , and our admiration not so much as palliated . this place might also admit another considerable , as terrible to the most daring curiosity as the former ; and that is the ineffable pernicity , whereby the aer is exploded from the lungs , that so it may attain the form of a voice . for , to the creation of a voice consonous , or unison to the sound of some one string on a lute ; it is necessary , that the aer be exploded by the lungs , with the same pernicity , as the other aer is impelled by the string in each of its most rapid vibrations , or alternate recurses , after its smart percussion by the finger , or plectrum . but this arcanum requires a galilaeo or mersennus , at least , to its due speculation . the observable most proportionate to our capacity , and competent to our praesent designation , is this ; that no sound is created without motion : and consequently , that the thing sonant , being endowed with solidity in some degree or compactness sufficient to resistence , ought either to be strook against another , that is solid and resistent ; as when a hammer is strook upon an anvil ; or against the aer , in flux and not much resisting , and that either by pulsation of the aer by a solid , as when the string of lute percusseth ●he aer ; or the pulse of the solid by the aer , violently agitated , as in all p●●umatick , or wind instruments , where the stroke of the aer against the sides of the concave causeth the sound . in the former instance , it is not necessary to the creation of a sound , that the collision be made by a motion rapid ; because the resistence , on either part equal , causeth that when the access or appropinquation of one solid to the other is continent , the aer interposed is continently impelled and repelled reciprocally : and as the aer becomes the more hardly distrest on each part , by how much neerer the two solids approach each other ; so proportionately is the motion more rapid . so that , by that time the two solids touch each other superficially , the motion is encreased to the highest rapidity , and the distrest aer , no longer able to endure compression , or to go and come al●●rnately between the solids , now contingent , breaks forth laterally in round , and is diffused in shivers through all parts of the medium , so that arriving at the ear , it puts on the species of a sound . but , in the se●ond and third instances , it is necessary the motion of collision be far more rapid , in order to the creation of a sound : because the resistence , which is wanting on the part of the aer , must be compensated by the frequent pulses and repulses of it , as when the chord of an instrument percust , doth very frequently impel the aer , by its vibrations ( the greeks call th●m , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) or reciprocations ; or , as in wind instruments , where the inflated aer is , by quick reverberations from the sides of the concave , very often impulst and repulst . as for the motion of the aer , after its formation into a sound , from the sonant to the ear , therein is one particular worthy the wonder even of scholars : and that is , whatever be the vehemence or remissness of the collision , or force , by which the aer is exagitated , yet is the translation of the sound , thence resulting , through the intermediate space to the term of it sphaere , always equally swift . for experience demonstrates , that all sounds small and great , excited in one and the same place , though they differ much . in the extent of their sphears of audibility , are delated to that place in which they are heard , in equal time . this is easily observable in the reports of a cannon and a musquet , successively discharged at a mile distance . for , standing on a tower , or other eminent place , and noting the moment , first when the cannon is fired ( the report and f●ash being made both at the same instant ) and numbring how many pulses of your artery , o● how many seconds in a watch denoting them , intercede betwixt your ●ight of the flame , and hearing the report , and then accounting how many pulses , or seconds intervene betwixt the flash and report of a musquet ▪ you shall finde the number of these equal to the number of those . the reason o● this aequivelocity of unequal sounds , the stoicks ( apud plutarch . . placit . . & laertium lib. . ) well insinuate , while they affirm , 〈◊〉 the aer percussed , in regard of its continuity , is formed into man● rounds , such as those successively rising and moving on the surfac● of water , upon striking or throwing a stone into it ; which circle● made on the surface of water by a small stone , move in the same 〈◊〉 , and successively arrive at the margin of the river , or pool , in as small time , as those caused by a great stone . and aristotle ( . de anim. cap. ▪ ) expresly declares his judgement , that the reason of the delation of a sound from the sonant to the audient , is the continuity of the aer : though simplicius and alexander differently interpret that text , the one conceiving that he meant that a sound was translated through the medium by reason of sympathy among the parts thereof ; the other , by propagation of the like sound in all points of the medium successively , after the manner of species visible , according to the dream of aristotle . but all one it is to us , whether we conceive the motion of a sound made by propagation , or undulous promotion ; as to our praesent scope : since either sufficeth to explicate the cause , why a sound is longer before it arrive at the eare , than a visible species before it arrive at the eye ; because the visible species is transmitted from the object , neither by propagation , nor undulation , but directly , and therefore is capable of no retardment from the medium . as for the definite velocity of sounds , or determinate space of time , in which all sounds are delated to the extremes of their spheres ; we conceive it to be rhodus and saltus , in the general , inassignable : in regard of the vast disparity in their several extents , some sounds being scarce audible at the distance of yards , and others cleer and distinct at as many , nay twice as many miles distance . but , if we assume this or that determinate sound , and attain the praecise diametre of its sphere ; it is no difficulty to commensurate its velocity . for , mersennus ( in reflexion . plysicomath . cap. . & proposit. . ballistica . ) upon exact experiment , found the fragor of several cannons discharge in the court of the bast●le at paris , to arrive at his eare , after the flashes , at such a rate , that the sound pe●vaded ● . fathoms ( each containing six feet paris measure ) in the space of every second , or sixtieth part of a minute : and thereupon rightly concluded , that the report of a cannon flyeth at the constant rate of neer upon fathoms every minute , until it attain the extremes of it sphere . if this expedient for the measure of the time wherein sound is delated , seem either too costly or laborious ; you have another most cheap and easie praescribed by the lord st. alban ( in cent. . nat. hist. ) which is this . let one man stand in a steeple , having a lighted taper with him , and some vail put before the flame thereof ; and another , confaederate in the tryal , stand a mile off in the open field : then let him in the steeple strike the bell with a weighty hammer , and in the same instant withdraw the v●●l ; and so let him in the field account by his pulse what distance of time intervenes betwixt his sight of the light , and hearing of the sound . if the strokes of the artery , which are subject to variation , for many causes , seem less certain ; the seconds in a minute watch ( which are 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , aequ●temporaneous ) will be an exact measure of the interval , and so of the velocity of a sound . plura vid. apud mersennum lib. . harmonic . proposit . . another admirable secret there is in the motion of sound , which is , that no winde can accelerate , or retard it , but it is delated from the sonant to the audient in equal time , whether the wind be high or gentle , secund or adverse . for , a secund or favourable wind is incomparably slower in motion than a sound , as appears by the rack or drift of clouds , the undulation of corn fields , the successive inclination of the topsof trees in woods , the rowling of waves at sea , &c. but an adverse wind , though it may indeed disturb a sound ▪ or weaken it by suppressing some of its particles ( which is evident from h●nce , that all sounds attaining the eare against the wind , are not so clear and distinct , as when they are heard with the wind ; as in bells , whose noyse al●●rnately riseth and falleth in contrary gusts ) yet do all the particles that r●main uninterrupted , permeate the medium with equal velocity . this may be soon experimented either by cannons , as mersennus , or a cand●● and bell , as the lord bacon . sect . iii. the praemises duly considered , it can seem no paradox , that a sound is created ●n the aer , not so much by the velocity , as crebrity of motion : and no unnatural consequence thereupon , that the difference of an acute and ●●ave sound ariseth not from the greater and less swiftness or rapidity of 〈◊〉 motion , as aristotle and most of his sectators imagined ; but from the ●●●quency and infrequency thereof , as galilaeo , mersennus , and gassendus . to secure this by plain demonstration , take a lute string in your hand , and having fast●●ned one end thereof to some hook or pin in a wall , distend it gently ; and then percussing it with your finger , you may perceive the vibrations , or ac●urses and recurses alternately succeeding , but you shall hear no sound result●ng from it : because , as every vibration of the string is performed in 〈◊〉 time , so doth the aer thereby percussed arrive at the eare with such ●●●sible intervals betwixt each appulse , as that it leaves no impression there●● remaining ▪ , which is not expunged and consolidated before the invasion o●● second appulse . then stretch the string somewhat streighter , so that the ●ibrations thereof may become inobservable by the eye , in respect of th●●● frequency ▪ and you shall hear a certain du●l stridor , or kind of 〈◊〉 ; because the appulses of the aer , percussed by each vibration ▪ at the 〈◊〉 , will be almost continent , so that the time interjected betwixt each 〈◊〉 on the eare becomes imperceptible , and indistinguishable , nor can the fir●●●mpression on the sensory be consolidated before a second renew it , &c. this done and observed , encrease the distension of the string yet more , and p●●cussing it you shall perceive a clear sound to arise ; because as the vibratio● , so are the percussions of the aer , and their appulses to the eare far more continent , or more one , in regard the moments of time intercedent betw●●● the successive strokes , are more short and imperceptible . and wha● 〈◊〉 here say of the reason of a sound resulting from a lute-string , the sam● 〈◊〉 proportion , is to be conceived of all other sounds created in wind 〈◊〉 , where the aer is the percutient . for , the breath easily and gen●●y inflated into a flute , cornet , trumpet , &c. yields no sound at all ; 〈◊〉 because the pulses and repulses of the aer from the sides of the 〈◊〉 are so infrequent , as to have the intervals of time distinguishable ▪ 〈…〉 aer likewise slowly emitted from the lungs ( the great exempla● to 〈◊〉 ●neumaticks ) makes no voice , onely because it is not frequently enough reverberated from the sides and annulary cartilages of the vocal artery , and consequently the appulses of it to the eare being proportionately infrequent , cannot , by their coition or union into one stronger appulse , make any sensible impression on the sensory . but the aer then becomes son●nt , when it is efflated with vehemency , in respect of its more frequent appulses to the sensory , respondent to the more itterated pulses and repulses , or reverberati●ns of the sides of the vocal artery . thus also , when you draw your finger gently along a table , or put a hammer on an anvil easily , you shall hear no sound ; because the repercussions of the aer caused by that gentle motion , are so far asun●e● in time , as never to become continent , or conjoyned : and consequently , the appulses of the percussions to the eare being alike infrequent , can never make a sensible impression on the a●ousti●k nerve . and this we conceive more than sufficient evidence of the verity of the first part of our thesis ; that a sound is not generated in the aer by the velocity , but crebrity of motion : unless in a remote dependence , as velocity is the cause of crebrity . as for the remainder , viz. that an a●ute sound ariseth from more frequent , and a grave sound from l●s● frequent percussions of the aer : the certitude hereof may be easily conc●u●ed from this experiment . fasten a long lute-string at one extreme on a hook n●yled to a wall , and suspend a small weight at the other ; then strike the string at convenient distance above the weight : and you shall observe the swings , or vibrations of it to be so slow , as th●t you may measure the time of each , by the systole and di●stole of your pulse , or the seconds in a minute watch. then wind up the chord exactly to the half , the same weight continuing appended , an● percuss it , as before : and you shall finde the vibrations of it to be doubly swifter than the former , to that one vibration shall be in time respondent to two pulses . again , abbreviate the chord to half , and having percusse● or abduced that half , which is now but a fourth part of the whole ; you shall observe the vibrations to be again doubled in frequency , in respect of the second , and qua●rupled in respect of the first ; so that now reciprocati●ns shall be isochr●nical to one pulse . this effected , continue this determinate abbreviation of the chord , by subdividing it into halfs successively until the reciprocations become so swift and frequent , as to be indistinguishable by the sense though still y●u deprehend their velocity and crebrity to be encreased at a certain rate , i. e. duplicated upon each dimidiation of the chord , when the aer is so frequently percussed by it ▪ as that it becomes sonorous , or ●ctually sonant . then aga●● d●mid●●te the sonant remainder of the chord , and upon percussion you shall observe the sound thereof to be more acute by a whole octave , than the former● and thence you cannot but concede , that the acuteness of this half of the sonant chord , above that of the whole sonant chord , is caused only by the doubly more frequent percussions of the aer , and proportionate strokes of the sensory . and , because a quadruplicate weight produceth the same effect , being ●ppended to the whole of the sonorous chord , as a simple weight doth in the half , as to the duplication of the celerity and frequency of the vibrations ▪ in the same moments : hence is it , that if you encrease the weight , retaining the same longitude of the chord , by degrees , until you advance the sound thereof to an eighth ▪ it ●s mani●est , that the reciprocations of it are still doubly more swift and frequent , than those caused by the former weight . moreover , what we affirm concerning the half of the sonorous chord , in respect of an octave ; holds true , in proportion also of the thirdparts of ●he chord , in respect of a fifth , of the dodrantal , or quarters , in r●spect of a fourth , and so of the rest of the musical notes . for , in a very long chord , if you stop upon the third part of the half thereof , and p●●cuss the bessal , o● two thirds of the half remaining at liberty : the proportion of its reciprocations will not be duple , but sesqui●steral in respect to those of the whole length ; i. e. vibrations of the chord will not respond in time to one pulse of the artery , nor . to . but . to . and , if you stop on the fourth part ; then will the reciprocations of the ●●mainder be in proportion sesquitertial , i. e. vibrations shall be isochro●●cal to pulses . according to the same method , if you stop on the th ▪ part of the chord ; the proportion of its vibrations , to that of the former , will be sesquiquartal : if the th part , sesquiquintal ; and so consequent●● of all other notes . so that it seems easily determinable , by this scale , what is the proportion of the strokes inflicted on the eare in every acute sound , comp●●●●ively to those inflicted by every grave : and this not onely in the sounds o●● ▪ string , but all others of the like original . to instance ; when a boy sings with a man , and emits a note more acute by an eighth● it is to be conceived , that the aer efflated from the vocal artery of the boy , is doubly swifter in its motion , or doubly more frequent in its r●●●●berations from the sides of the wind-pipe , in respect of the double narrowness thereof , than that expired from the vocal artery of the man. and , hence we may occasionally advertise , that by how much the more 〈◊〉 any man would sing ; by so much more streightly or narrowly mus●●e compress his wind-pipe : that so the aer may issue forth more distrest and streightned , having suffered the more frequent reverberations from the sides and rings of the same . and this 〈…〉 noble fountain from which many of our m●dern theorical music●●● have drawn the reason of the suavity of the●r consonan●●s , and acerbity or ingratefulness of their dissonanc●● ▪ ●nd that not without mature consideration . for , when two sounds , ●●●chronical in their creation , arrive at the eare in the same instant ▪ and 〈◊〉 it with pleasure , or a kinde of sweetness ; the cause of that sweetn●●●an be no other but this , that the percussions of the aer generating 〈◊〉 two sounds , become so united , as to leave no sensible 〈…〉 might grate or exasperate the tender sensory : and on the other si●● ▪ the reason of the discord or insuavity of two sounds , at once emitted , is onely this ; that they are not united , so that the eare deprehen●● and dislikes their discrepancy . again , the several degrees of thi● suavity and insuavity among musical sounds , cannot be deduced with equal probability from any other original , as from the variety of 〈◊〉 , and discrepancy of the percussions creating the sounds . to ●●emplifie in the sounds resulting from strings ; take two 〈…〉 in their materials , length , and thickness , and 〈…〉 ●qual weight● , or force ; and when you percuss them with one 〈◊〉 they will emit equal sounds , or that consonance , which is called an u●●son : which will be therefore grateful , because as the vibrations of 〈…〉 , so will the strokes inflicted on the sensory , have the same 〈◊〉 each to other , as one hath to one ( the proportion of equality● 〈◊〉 consequently will be equal in number and time , so as to affect the sensory most equally and unitedly . but if you abbreviate one of the strings exactly to half ; because ( according to the praemises ) the sounds resulting from them , at once percust , must make an eighth , or that consonance , which the greeks name 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and we a diapason : therefore must that eighth be eminently grateful also ; insomuch as though after the coalition of two strokes , one resulting from the shorter string be insociate , yet doth the immediately consequent stroke thereof perfectly unite with that of the longer string , and so the unition is made alternately , or at every other stroke ; and therefore doth this consonance invade the sense of all others , an unison only excepted , most unitedly and equally , and consequently is the most pleasant and charming of all consonances , after an unison . and when you make the proportion of the short string exactly sequialteral to that of the long ; because the sounds resulting from them , both at once percussed , make a fifth , or diapente : therefore will that consonance also have a considerable degree of sweetness , though short of that of an eight ; insomuch as though two strokes pass insociated , yet doth the union follow in every third , and so the unition is sufficiently frequent to please the sense , which is best delighted with that object , in which is the least difference of parts , according to that fourth praecogn . of des cartes ( in compend . musicae , pag. . ) illud objectum facilius sensu percipitur , in quo est minor differentia partium . again , if you make the proportion of the short string sesquitertial to that of the long ; because a fourth , or diatessaron , doth result from the percussion of them together , therefore will that consonance be likewise competently grateful : in respect that after three insociated strokes , the coition falls in every fourth . to contract ; the same holds in proportion exactly true also in sesquiquartal and sesquiquintal proportions , from which arise thirds major and minor ; and of superbiparting thirds , and supertriparting fifths , from which arise sixths major and minor ; and finally , in all compound consonances , such as disdiapason , &c. for , alwayes the consonance is by so much more grateful , by how much more frequently the strokes unite in the sensory : and è contra . whence is generated the dissonancy , or ingratefulness of sounds , when ever the strokes either too rarely , or never unite : because , in those cases , the sense is held in a kind of lasting distraction , and unless a restitution of the distracted parts of the sensory be made by some coalitions , and those sufficiently frequent ( which are a kind of balsam , to cure the gratings and dissolutions ) the sensory must be mis-affected with a kind of laceration , and undergo that dolour unwittingly . this the skilful musician foreknowing , endeavours to praevent , by making a diapason , or perfect consonance tread upon the heels of a dissonance , for varieties sake usually inserted into tunes : thereby with advantage consolidating the ulceration of the sensory caused by the praecedent discord , and making the harmony the more grateful ▪ as health is most grateful immediately after sickness , and a calme after a tempest . and this is the reason , why an eighth is by many reputed a more pleasing consonance , than an alnison ; viz. in respect of the distraction , which succeeds alternately from the dissociated strokes of one of two strings together percust : and not in respect of its comprehension of all other consonances , as des cartes seems to conclude ( in cap. . compend music. ) if this genealogy of all musical consonances seem either obscure , or taedious ; you may please to accept it in epitome , thus . the vibrations of chords are , according to most exact observation reciprocally proportional to the length of the string , having the same weight . to the weight at the string , having the same length . whence many have concluded , that all consonances in musick proceed from the speedier union of these vibrations in their terms . the terms of an eighth are in proportion , as to therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an eighth . fifth are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an fifth . fourth are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an fourth . sixth major are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an sixth major . third major are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an third major . third minor are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an third minor . sixth minor are in proportion , as — therefore the space of vibrations , in the graver term , are just equal to vibrations in the acuter term of an sixth minor . hereupon our harmonical authors ( whose pythagorean souls feast themselves with the ravishing , though silent musick of numbers ) for the most part account an eighth the first of consonances , because an union is made before a second vibration in the graver term ; a fifth the second consonance , because an union is made before a third vibration in the graver term , &c. according to the scheme . but this so universally celebrated melothetical foundation hath been very lately shook by that no less erudite , than noble author of the animadversions on des cartes musick compendium , the lord viscount brouncker ; ( whose constant friendship , and learned conversation , i must profess to have been one of the cheifest consolations of my life . ) who having , upon profound , and equitable examination , found this great defect therein , that according to the former derivation of all musical consonances , a third major must succeed a fourth and sixth major , and the proportion of to makes a consonance as well , and before a sixth minor ; which is manifestly repugnant to experience : hath enriched the world with a new hypothesis of his own happy invention , sufficiently extensible to the full solution of all musical phaenomenaes . according to which the consonances arise ( physically ) from the vibrations of chords , not in respect of their union , but ratio-harmonical proportion , as he is pleased to call it : and this upon very good reason , since , the vibrations being proportional to the chords , and the chords so proportionally divided ; it is of meer necessity , that their vibrations have the same proportions . but of this , the competent enquirer may understand more from his animadversions , &c. and this speculation , touching the nativity of musical consonances ; hath engaged us to touch upon that quicksand , from which none the most adventurous curiosity hath ever yet returned with full resolution ; and that is that eminent problem , quando sonus harmonicus à nervo fieri incipiat ? in what instant an harmonical sound , created by a chord of an instrument percussed , or abduced from its directness , is begun ? ( ) some there are , who observing that , when a chord is abduced from its direct line e to c , and returns it self from c to e , if a piece of wollen cloth , a mans finger , or ought else that may suppress its motion , be so set as to arrest it at e ; then is no harmonical sound created , either in its first excurse from e to c , nor recurse from c to e : have upon this experience concluded , that the concinnous sound is begun in the first recurse of the chord from d to e ; because they suppose , the chord then to reverberate the aer , which pursued it ( à tergo ) from c to d , and force it by contrary violence to fly back again from d to c by e : so that the aer at e , being on both sides distrest by that moving violently from c to e ▪ on one hand , and that lastly impelled from d to e , on the other , must suffer the highest condensation , or compression , or percussion of all the other aer within the space cd , and consequently be the original of the sound . ( ) others have affirmed the original of the sound to be from c to e , the space of the first recurse : and their inducement thereto is this experience . if a chord of perches length be with sufficient force extended , and then abduced from its line of direction to the distance of feet , more or less ; it will yeild a kind of stridor , or grave sibilation , in its spontaneous recurse from c to e : which sound would perhaps be concinnous , if included in some instrument of sufficient capacity . to which they add , that wands or rodds being switcht in the aer , and gun-shot in their flight , emitt a singing noyse , though they are impelled only one way , and have no recurses , or doublings in the aer . but , to this it may be answered , ( ) that all these bodies may more justly be conceived to yeild a sound only in this respect ; that the inaequalities in their superficies so distress the aer in their rapid motion , and by frequent reciprocations in their small cavities variously agitate the same , that it suffers such circumvolutions as are tantamont to their recurses . ( ) that no bullet shot from a gun would yeild any sound at all , if it were exactly sphaerical , polite , and hard , and flew directly without that volutation , or circumvolution , which the resistence and circular returns of the aer constantly impress upon it . ( ) that the sibilation or hissing noise made by the long chord , in its recurse from the feet abduction , is not , nor ever can be concinnous : and therefore the experience is impertinent to this problem . ( ) a third sort there is , who opinion the harmonical sound then to begin , when the chord is first impelled from e to c ; so that the c●ord should produce a sound in the extremity or period of every flexion , i. e. in c and d , at alternate recurses : and consequently , that no sensible sound is produced in any part of the whole intermediate space betwixt cd . and the ground these stand upon , is the experience of cloth , which being violently shook in the aer , for the excussion of dust , doth only then emit a smart sound , or rapp , when attaining the extremity of its flexion , it percusseth the superior aer , and is in the manner of sails , swelled up by the inferior aer . but , in this instance , and that consimilar one of coach-whips , it is almost evident even to the eye , that the rapp is made only by the doubling of the cloth , or chord , at the end of their flexion : and therefore we are not convinced , that the concinnous sound is then begun , as these persuade , in either c or d the period of each flexion ; especially , when the chord in c and d seems rather to quiesce , than move ▪ and some quiet must intercede betwixt two contrary motions of the same thing . ( ) but ●nsomuch as all sounds are caused by the motion of the aer ; and the sound alwayes is loudest , where the motion of the aer is most rapid ; 〈…〉 the whole sonorous line , or space betwixt c and e , the motion of the aer intercluded is most swift , when the chord returns from c to e : therefore doth mersennus ( to whose judgment we most incline , in this nicety ) conclude ; that the harmonical sound is begun in the beginning of the first recurse of the chord from c to e : and that it is then of the same acuteness , as are all the subsequent sounds made by the subsequent recurses ; because the reason of the first recurse seems to be the same with that of all the consequent . to this some have objected ; that the sound of the first recurse is too expedite and short , to be perceived by the ear : since even the eye , incomparably more prompt in the discernment of visibles , cannot behold an object , whose apparence , or praesence exceeds not the duration of the foresaid recurse of the chord from the extreme of its flexion c to e ; which doth scarce endure the ● part of a minute . but this objection is soon dissolved by experience , which testifieth , that if a quill , or other impediment be placed some small space beyond e towards d , so that the chord may complete its first recurse from c to e , without interruption : then will a sound be created , and such as hath sufficient acuteness ; though it be scarce momentany in duration , because the frequency of its recurses is praevented . many other problems there are , concerning the reasons of sounds , wherewith the insatiate curiosity of naturalists hath entertained it self , in all ages : but , among them all we shall take cognizance of only those more eminent ones , which as they seem most irreconcilably repugnant to our theory , when proposed ; so must they much confirm and illustrate the dignity thereof , when clearly dissolved by us , without the least contradiction to , or apostacy from our principles assumed . since the unstrained solution of the most difficult phaenomenaes , by the vertue of any hypothesis , is the best argument of its verity and excellency above others , that fail in their deduction to remote particulars . problem . whether may a sound be created in a vacuum , if any such be in nature ? solut. to solve this ( by many accounted inexplicable ) aenigme , we need only to have recurse to our long since antecedent distinction of a vacuity disseminate , and coacervate : for , that once entered our judgment , we cannot indubitate that ingenious experiment of gaspar berthius , laureat mathematician at rome ( frequently , and alwayes with honourable attributes , mentioned by father kircher , in sundry of his physicomathematical discourses ) which sensibly demonstrateth the actual production of a sound , in a disseminate vacuity . the experiment is thus made . having praepared a large concave and almost sphaerical glass , aemulating the figure of a cucurbite or cupping-glass ; fix a small bell , such as is usual in striking watches of the largest size , on one side of the concave thereof , and a moveable hammer , or striker , at fit distance , on the other , so as the hammer being elevated may fall upon the skirts of the bell : and then lute or coement on the glass , firmly and closely ( that all sensible insinuation of the ambient aer be praevented ) to one extreme of a glass tube , of about an inch diametre in bore , and or feet in length . then , reversing the tube , pour into it a sufficient quantity of quicksilver , or water , to fill both it and the head exactly . this done , stop the other extreme of the tube with your finger , or other stopple accommodate to the orifice ; and after gentle inversion , immerge the same to a foot depth in a vessel of water , and withdraw your stopple , that so much of the quicksilver contained in the head and tube , as is superior in gravity to the cylindre of aer , from the summity of the atmosphere incumbent on the surface of the water in the subjacent vessel may fall down , leaving a considerable void space in the superior part of the tube . lastly , apply a vigorous loadstone to the outside of the glass head , in the part respecting the moveable extreme of the hammer ; that so , by its magnetical effluxions transmitted through the incontiguities or minute pores of the glass , and fastned on to its ansulae or smal holds , it may elevate the same : which upon the subduction of its attrahent , or elevator , will instantly relapse upon the bell , and by that percussion produce a clear and shrill sound , not much weaker than that emitted from the same bell and hammer , in open aer . now , that there is a certain vacuity in that space of the head and tube deserted by the delapsed quicksilver , is sufficiently conspicuous even from hence ; that the ambient aer seems so excluded on all hands , that it cannot by its periosis ( to borrow platoes word ) or circumpulsion , succeed into the room abandoned by the quicksilver , and so redintegrate the solution of continuity , as in all other motions . and that this vacuity is not total , or coacervate , but only gradual or desseminate , may be warrantably inferred from hence ; ( ) that nature is uncapable of so great a wound , as a coacervate vacuity of such large dimensions , as we have argued in our chapter of a vacuum praeternatural , in the first book : ( ) that a sound is produced therein , for since a sound is an affection of the aer , or rather , the aer is the material cause of a sound , were there no aer in the desert space , there could be no sound . wherefore , it is most probable , that in this so great distress ingenious nature doth relieve herself by the insensible transmission of the most aethereal or subtile particles of the circumpulsed aer , through the small and even with a microscope invisible pores of the glass , into the desert space ; which replenish it to such a degree , as to praevent a total though not a dispersed vacuity therein : and though the grosser parts of the extremly comprest aer cannot likewise permeate the same slender or narrow inlets ; yet is that no impediment to the creation of a sound therein , because the most tenuious and aethereal part of the aer , is not only a sufficient , but the sole material of a sound , as we have more than intimated in the . art. . sect. of the present chapter . the only difficulty remaining , therefore , is only this ; why the sound made in the disseminate vacuity should through the glass-head pass so easily and imperturbed , as to be heard by any in the circumstant space ; when common experience certifieth , that the report of a cannon , at the distance of only a few yards , cannot be heard through a glass window into a room void of all chinks or crannies ? nor need any man despair of expeding it . for , whoso considers the extraordinary and inscrutable wayes to which nature frequently recurrs , in cases of extreme necessity ; and that the distress she undergoes in the introduction of this violent vacuity ( where her usual remedy the peristaltick motion , or circumpulsion of the aer , is praevented by the interposition of a solid ) is much more urgent than that she is put to in the compression of the ambient aer by the explosion of canons ( where the amplitude of uninterrupted space affords freedome of range to the motion imprest ) we say , whoso well considers these things , cannot doubt , but that it is much easier to nature to admit the trajection of the sound produced in the disseminate vacuity , through the pores of the glass-head , than the transmission of an external sound into a close chamber , through a glass window , where is no concavity for the corroboration or multiplication of the sound , and consequently where the impulse is far less ( respective to the quantity of the aer percussed ) and the resistence as much greater . problem , . whence is it , that all sounds seem somewhat more acute , when heard far off ; and more grave , near at hand : when the contrary effect is expected from their causes , it being demonstrated , that the gravity of a sound ariseth ( mediately , at least ) from the tardity , and acuteness from the velocity of the motion , that createth it ; and many great clerks have affirmed , that the motion of a sound is less swift far off from , than near to its origine , according to that general law of motion , omnia corpora ab externo mota , tanto tardius moventur , quanto à suo principio remotiora fuerint ? solut. no sound is really , but only apparently more acute at great , then at small distance ; and the cause of that semblance is meerly this : that every sound , near its origine , in regard of the more vehement commotion , and proportionate resistence of the aer , dependent on its natural elater , or expansory faculty , doth suffer some obtusion , or flatning ; which gradually diminishing in its progress or delation through the remoter parts of the medium , the sound becomes more clean , even and exile , and that exility counterfeits a kind of acuteness . problem . why doth cold water , in its effusion from a vessel , make a more full and acute noise , than hot or warm ? solut. the substance of cold water , being more dense and compact , must be more weighty , and consequently more swift in its fall , and so the noise resulting from its impulsion of the aer , more sharp than that of hot : which being rarefied by the fire , or made more lax in the contexture of its particles , looseth something of its former weight , and so hath a slower descent , and in respect of that slowness , produceth a weaker and flatter sound . and this is also the reason , why iron hot yieldeth not so smart and full a sound , as when 't is cold . problem . why is the lowing of a calf much more deep , or base , than that of an oxe , cow , or bull , at their standard of growth : contrary to all other animals , which have their voices more shrill and acute , when they are young , than when they are old ? solut. the cause of this singularity is found only in the peculiar constitution of the larynx of a calf ; which is in amplitude equal to , and in laxity and moysture much exceeds that of an oxe , cow , or bull full grown ; and so age doth contract and harden , not ampliate the same , as in all other animals : and it is well known that the wideness and laxity of the asper artery , is the cause of all grave or base voyces . problem . why is a dissonance more easily discovered by the ear , in a barytonous , or base voyce , or tone , than in an oxytonous or treble ? solut. because the barytonous voyce is of a slow motion , and the oxytonous of a swift : and the sence doth ever deprehend that object whose apparence is more durable , more clearly and distinctly than that , whose apparence is only instantaneous , or less lasting . chap. vii . of odovrs . sect . i. whoever is natively deprived of any one sense , saith aristotle ( in analyticis ) is much less capable of any science , than he who hath all five fingers on the left hand of his soul ( to use the metaphor of casserius placentinus , in praefat . ad lib. de sens . organ ) or all the organs of the sensitive faculty complete : and his reason is that general canon , nihil est in intellectu , quod non prius fuerit in sensu ; the senses being the windows , through which the soul takes in her ideas of the nature of sensible objects . if so , whoever hath any one sense less perfect than the others , can hardly attain the knowledge of the nature of objects proper to that sense : and upon consequence , the cognition of the essence of an odoure must be so much more difficult to acquire , than that of visibles and audibles , by how much less perfect the sense of smelling is in man , than the sight and hearing . and , that man , generally , is not endowed ( for , we may not , with our noble country man sir kenelme digby charge this imperfection altogether upon the errors of our diet ; because we yet want a parallel for his iohn of liege , who being bred savagely among wild beasts , in the forrest of ardenna , could wind his pursuers at as great distance , as vultures do their prey , and after his cicuration or reduction to conversation with men , retained so much of the former sagacity of his nose , that he could hunt out his absen● friends by the smell of their footsteps , like our blood-hounds ) we say , that man is not generally endowed with exquisiteness of smell ; needs no other eviction , but this : that he doth not deprehend or distinguish any but the stronger , or vehement sorts of odours ; and those either very offensive , or very grateful . but , albeit this difficulty of acquiring the knowledge of the essence and immediate causes of odours , hath its origine in the native imperfection of our sense accommodate to the perception thereof : yet hath it received no small advance from the obscurity of our intectuals , the errors of human judgement , and the common effect thereof , the contrary opinions of philosophers . for , however they unanimously decree , that the proper object of smelling is an odour ; and the adaequate sensory , ordained for the apprehension of it , the mammillary processes of the brain , or two nervous productions derived to the basis of the nose : yet could they never agree about the chief subject of their dispute , the quiddity , or form of an odour ; or the commensuration betwixt the same , and the odoratory nerves , the theory whereof seems most necessary to the explanation of the reason and manner of its perception and distinction by them . thus , on one side of the schools , heraclitus , cited by aristotle ( de sensu & sensili , cap. . ) is positive , that the smell is not affected with only an incorporeal quality , or spiritual species ; but that a certain subtle substance [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] or corporeal exhalation , emitted from the odorous object , doth really and materially invade and affect the sensory . ( ) and epicurus ( in epist ad herodot . apud diogen . laertium , lib. . ) seconds him with somewhat a louder voice ; existimandum est , odorem non facturum ullam sui impressionem , nisi ab odora re usque deferrentur moleculae se● corpuscula quaedam , ea ratione commensurata ipsi olfact●● sensorio , u● ipsum moveant afficiant ve ; alia quidem perturbate ac discrepanter ex quo odores ingrati sunt ; alia placide & accommodate , ex quo iucundi sunt odores : men are to conceive , that an odour could make no sensible impression of it self , unless there were transferred from the odorous object certain substantial effluxes , or minute bodies , so commensurate or analogous to the peculiar contexture of the organ of smelling , as to be capable of affecting the same ; and those either perturbdly and discordantly , whence some odours are ingrateful ; or amicably and conveniently , and those odours are grateful . ( ) and gal●n , attended on by most of the aesculapian tribe , sings the same tune , and in as high a key as either of the former ; saying , ( in lib. de instrum . olfact cap . ) id quod a rerum corporibus exhalat , odoris substantia est : though casserius placentinus ( de fabric . nasi , sect. . cap. . ) hath endeavoured to corrupt the genuine sense of those words , by converting substantia into subjectum , as if galen intended only that the exhalation from an odorous body was only the subjectum inhaesionis , and the odour it self meerly the quality inhaerent therein . contrary to the rules of fidelity and ingenuity ; because incongruous both the letter of the text , and the syntaxis thereof with his whole enquiry . ( ) and the lord st. alban , though a modern , yet not unworthy to enter the chorus with the noblest among the ancients , though he had too frequently used his tongue to the dialect of immaterial qualities , and spiritual images , in his discourses of the other senses ; doth yet make a perfect unison with galen , in this particular , delivering his judgement in most full and definite termes , thus : certain it is , that no smell issueth from a body , but with emission of some corporeal substance ; ( sylva sylvar . cent. . experim . . ) on the other side , we hear the great genius of nature , as his idolaters miscall him , aristotle , and that most numerous of sects , the peripatetick , vehemently contending , that an odour belongs to the classis of simple , or immaterial qualities ; and that though it be wafted or transported on the wings of an exhalation , from the odorate body to the sensory : yet is the sensory affected onely with the meer image , or intentional species thereof . now the moments of authority being thus equal on both sides , our province is to determine the scales by the praepondium of reason , i. e , with an even hand to examine the weight of the arguments on which each of these contrary opinions is grounded to begin with the later , as the most epidemical and generally entertained ; we find the principal base of it to be only that common axiome , sensus non percipiunt substantias , sed tantum earum accidentia , that no sense is invaded and actuated into sensation by the real or material , but onely the intentional species of the object : which being weak of it self , and by us frequently subverted in our praecedent discourses ; the whole superstructure thereon relying is already ruined , and they who will reaedifie it , must lay a new foundation . but , as to the former , that an odour is a perfect substance , by material impression on the sensory causing a sensation of it self therein ; this seems a truth standing upon such firm feet of its own , that it contemns the crutches of sophistry . for ( ) no academick can be so obstinate , as not to acknowledge , that there is a certain effluvium , or corporeal exhalation from all odorous bodies , diffused and transmitted through the aer ; as well because his own observation doth ascertain him , that all aromatiques and other odorous bodies , in tract of a few years , confess a substantial contabescence , or decay of quantity ; which makes our druggists and apothecaries conserve their parcels of ambre grise , musk , civit , and other rich perfumes , in bladders , and those immured in glasses , to praevent the exhaustion of them by spontaneous emanation : as for this , that the odour doth most commonly continue vigorous in the medium , a good while after the remove of the source , or body from which it was effused . and aristotle himself , after his peremptory negative , odorem non esse 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , effluxionem : could not but let slip this affirmative , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quod effluit ex corporibus , ipsa est odorum substantia . ( ) common experience confirms , that odours are vigorous and potent , not only in the production of sundry affections in the brain , good or evil , according to their vehemency and gratefulness or noysomness , by the refocillation or pollution of the spirits ; but also in the vellication and frequently the corrosion of tender investment of the nostrills . thus much the reverend oracle of cous well observed in aphorisme sect. ; odoramentorum suffitus muliebria educit , & ad alia plaerumque utilis esset , nisi gravitatem capitis inferret : and galen supports with his opinion and arguments , that pleasant odours are a kinde of nourishment of the spirits . besides , plutarch reports , that he observed catts grow mad onely by the smell of certain odoriferous unguents : and levinus lemnius ( de natur. miracul ) hath a memorable story of certain travellers , who passing through large fields of beans in the flower , in holland , become phrantick meerly with the strength of their smell . and all physicians dayly finde , that good smels , by a recreation of the languid spirits , speedily restore men from swooning fits ; as evil scents often induce vomitings , syncopes , vertigoes , and other suddain symptomes . nay , scarce an author , who hath written of the plague and its causes , but abounds in relations of those accursed miscreants , who have kindled most mortal infections , by certain veneficious practices , and compositions of putrid and noysom odours : witness petrus droetus ( de pestilentia , cap. . ) wierus ( de venificiis lib. . cap. ) horatius augenius ( lib. de peste , cap. ) hercules saxonia ( de plica , cap. . & . ) thomas iordanus ( de pestis phaenomen . tr . . cap . ) and sennertus , out of nich. polius in haemerologia silesiae , ( in lib. de peste , cap. . ) which prodigious effects clearly proclaim the mighty energy of their causes , and are manifestoes sufficient , that odours justly challenge to themselves those attributes , which are proper onely to corporiety : nor can ought but downright ignorance expect them from the naked immaterial qualities , or imaginary images of the peripatetick . ( ) the manner of the odours moving , or affecting the sensory can never be explained , but by assuming a certain commensuration , or correspondency betwixt the particles amassing the odour , and the contexture of the olfactory nerves , or mammillary processes of the brain delated through the spongy bone . for ( ) it is canonical , that no immaterial can operate upon a material , physically ; the inexplicable activity of the rational soul upon the body by the mediation of the spirits , and that of angelical essences excepted . ( ) though an odour , diffused through the aer , chance to touch upon the hands , cheeks , lips , tongue , &c. yet doth it therein produce no sensation of it self ; because the particles of it hold no proportion to either the pores , or particles of which those parts are composed : but arriving at the organ of smelling , it cannot but instantly excite the faculty therein resident to an actual sensation , or apprehension of it ; in regard of that correspondency in figure and contexture , which the particles of it hold to the pores and particles of the odoratory nerves . certainly , as the contexture of the odoratory nerves is altogether different from that of the tongue ; and so the minute bodies of them , as well as the small spaces intercepted among those minute bodies , in all points of their superficies not contingent , are likewise of a dissimilar configuration from the particles and intercepted vacuola of the tongue : so also is it necessary , that the small bodies , which commove and affect the contexture of the odoratory nerves , be altogether dissimilar to those , which commove and affect the contexture of the tongue , since , otherwise all objects would be in common , and the distinction of senses unnecessary . now ( lest we should seem to beg the quaestion ) that the sensation is effected in the odoratory nerves , only by the figures of the particles of an odour ; and that the variety of odours depends on the variety of impressions made on the sensory , respective to their various figures and contextures : this is not obscurely intimated in those formerly recited words of epicurus , molecularum , sive corpusculorum quaedam perturbate ac discrepanter , quaedam verò placide ac leniter , seu accommodatè se habere , ad olfactus sensorium . the substance whereof is this , that because the particles and contexture of some odours are such , that they strike the sensory roughly and discordantly to the contexture thereof ; therefore are they ingrateful : and on the contrary , because other odours have such particles and such contextures , as being smooth in figure , strike the sensory gently , evenly and concordantly to the contexture thereof ; therefore are they grateful and desiderable . we might have introduced plato himself , as lighting the tapor to us , in this part●cular ; insomuch as he saith ( in timaeo ) that the sweet sort of odours [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] de mulcere , & quâ inseritur , amicabiliter se habere , doth softly stroke , and cause a certain blandishment in the sensory : but , that the kinde of noysom or stinking odours [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] doth in a manner exasperate and wound it . to this incongruity or disproportion betwixt offensive smells and the composure of the odoratory nerves , the profound fracastorius plainly alludeth , in his ; proportionalitèr autem se habent & odores , quorum ingratissimus est , qui f●tidus appellatur , quique abominabili in saporibus respondet ; nam & hic ex iis pariter resultat , quae nullam habent digestionem , nec rationem mistionis , sed confusionem èmultis fere ac diversis , qualia fere sunt putrescentia , in quibus dissoluta mistione evaporatio diversorum contingit . ( de sympath . & antipath . cap. ) importing withal , that the reason why the stink of corrupting carcasses is of all other most noysom , is because the odours effuming from them consist of heterogeneous or divers particles . if you had rather hear this in verse , be pleased to listen to that tetrastich of lucretius ; non simile penetrare , putes , primordia formâ in nares hominum , cum taetra cadavera torrent ; et cum scena croco cilici perfusa recens est , araque panchaeos exhalat propter odores . upon which we may justly thus descant . as the hand touching a lock of wool , is pleased with the softness of it ; but grasping a nettle , is injured by that phalanx of villous stings , wherewith nature hath guarded the leaves thereof : so are the nostrills invaded with the odour of saffron , delighted therewith , because the particles of it are smooth in figure , and of equal contexture ; but invaded with the odour of a putrid carcase , they are highly offended , because the particles thereof are asper in figure and of unequal contexture , and so prick and dilacerate the tender sensory . moreover , whereas there is so great variety of individual tempe●aments among men , and some have the contexture of their odoratory nerves exceeding dissimilar to that of others ; hence may we well derive 〈◊〉 cause of that so much admired secret , why those odours , which are not onely grateful , but even highly cordial to some persons , are most odious and almost poysonous to others . infinite are the examples recorded by physicians , in this kinde ; but none more memorable than that remembred by plutarch ( lib. . advers . coloten . ) of berenice and a certain spartan woman , who meeting each other instantly disliked and fainted , because the one smelt of butter , the other of a certain fragrant ointment . however , the rarity of the accident will not permit us to pass over the mention of a lady of honor and eminent prudence , now living in london ; who doth usually swoon at the smell of a rose ( the queen of sweets : ) and sometimes feasts her nose with assa faetida ( the devils turd , as some call it ) than which no favour is generally held more abominable ; and this out of no affectation , for her wisdom and modesty exclude that praetence , nor to prevent fitts of the mother , for she never knew an hysterical passion , but in others , in all her life , as she hath frequently protested to me , who have served her as physician many years . again , as this assumption of the corporiety of an odour doth easily solve the sympathies and antipathies observed among men , to particular smells ; so likewise doth it yield a plain and satisfactory reason , why some br●●t animals are pleased with those odours ; which are extremely hateful to others . why doggs abhorr the smell of wine , and are so much delighted with the stink of carrion , as they are loath to leave it behind them , and therefore tumble on it to perfume their skins therewith ? why a cat so much dislikes the smell of rue , that she will avoid a mouse that is rubbd with the juice thereof ; as africanus ( in geoponicis ) ? why mice are poysoned with the scent of rododaphne , or oleander , commonly named rose-bay-tree ; as apuleius , and from him weckerus ( de secretis animal . ) ? why serpents are driven from gardens by the smell of citro●s as galen affirms ; when yet they solace themselves with that of savin , which our nose condemns ? why cocks cannot endure the breath of garlick ; which is soveraign incense to turkeys , and pure alchermes to their drooping yong ones ? why moths are destroyed by the fume of hopps ; which is ambre grise to bees , as mouffet ( de insectis ) ? for the caus● hereof wholly consists in the similitude or dissimilitude betwixt the particular contexture of the sensory , and the figures of the particles of the odour . the materiality of an odour being thus firmly commonstrated ; the next considerable is the generation , and proxime efficient cause thereof . and herein aristotle came neerer the truth , than in his conception of the essence of it ; for that assertion of his , odorem gigni & moveri beneficio caloris , that heat conduceth both to the generation and motion or diffusion of an odour , doth well deserve our assent . for , whether those minute masses , or small concretions , that constitute the body of an odour , be contained ch●●fly in some sulphurous substance , as the dissolutions and experiment● of chymistry seem to conclude ; or ambuscadoed in any other consisten●● whatever : yet still is it manifest , that they are deduced into act and seques●●ed from those dissimilar or heterogeneous bodies of earth and water 〈◊〉 surrund and oppress them , and so becoming more at liberty and unite● ▪ they more vigorously affect the sense , and all this by the energy of heat ▪ hence comes it , that all fruits are so much more fragrant , by how much more concocted and maturated by the warmth of the sun. that all aromaticks grow in hot climats . that all smells are stronger in summer , than winter ; as plutarch observes ( lib. de caus. natur. cap. . ) where he enquires , why in frost wild beasts leave but a cold scent behind them , when they are hunted . that all odoriferous druggs are hot , and suffer a perpetual exhaustion or expence of their halituous substance : so that who so would conserve their fragrancy , must embalm them in oyl , or incorporate them with gumms , or other substance not easily evaporable ; according to the common practice of all perfumers and confectioners ; or immure them in close conservatories , and that rather in great lumps , than small fragments , and in cold rather than hot rooms . hence it is also , that all botanicks hold it for an unquestionable axiome , omnia odorata esse calida ; so that some have undertaken to distinguish of the degrees of heat in plants and other simples , meerly by the vehemence or languor of their odour : and that aristotle ( problem . sect . . quaest . . ) affirms that all odorous seeds are calefactive , because heat is the efficient of an odour ; to which galen also subscribes ( de simpl . medicament . facul . cap. . ) from the nature & efficient of odours , we are conducted to their difference , or distinct species ; which is an argument involved not in the least difficulties . for , since the imperfection of our sense of smelling is such , that it is affectable only with the more vehement sort of them , which are but few in comparison to those many , which the sagacity of most bruit animals makes familiar to their deprehension , and so we remain ignorant of the greatest part of them ; and did we know them , yet should we be to seek for proper appellatives to express their particular natures : to deliver an exact table of all their distinctions , is not only difficult , but impossible . which naturalists well understanding , have been forced to the cleanly shift of transferring the distinct names of sapours over to the specifical differences of odours ; there being some manifest symbolism betwixt the two senses , and no obscure analogy betwixt the conditions of their objects : as aristotle insinuates in his affirmation , nullum corpus esse odoriferum , quod non pariter saporiferum existat ( de sens & sensil . cap. . ) that all odoriferous bodies are also saporiferous ; and in his definition of an olfactile , or odorable object to be , quod sapidae siccitatis diluendae ac diffundendae vim sortitur . well may we , therefore , content our selves with the discrimination of those kinds of odours , that fall under the cognizance of our sense ; and those are sweet , sower , austere , acerb , and fatt or luscious : as for putrid or faeti● odours , they have resemblance to bitter sapours , because as bitter things are o●ious and distastful to the pallate , and no man swallows them without some horror and reluctancy , so likewise doth the nose never admit rotten and cadaverous smells without loathing and offence . there is also another difference of smells , whereof one kind is either pleasant or unpleasant by accident , or upon circumstance ; as the smell of meats and drinks is pleasant to the hungry , but offensive to the full-gordged , and this sort is in common as well to beasts , as men : the other is pleasant , or unpleasant of their own nature , as the smells of herbs , flowers , perfumes , &c. which conduce neither to the excitement , nor abatement of appetite , unless they be admixt to meats or drinks ; to which stratis alluded , when taxing uripides he said , cum lens coquitur , unguenti nil infundito , and this difference is proper only to man. lastly , authors have divided odours into natural , and artificial , or simple and compound ; the latter whereof our luxury and delicacy have enhanced to such immoderate rates , that the confection of them is become an arte , and reduced to certain dispensatories and set praescripts , and that lady is not al-a-mode , who hath not her manuscript of recipes for perfumes , nay every street hath its myropolies or shops of sweets , of all sorts . finally , the medium inservient to odoration , is either aer , or water : yet neither according to essence , but infection , or impraegnation . that ●he aer is a convenient convoy , or vehicle of an odour , no man did ever doubt : and that water hath the like capacity , or perodorable faculty , though in an inferiour degree ; we may , with aristotle ( de histor . animal . . cap. . ) conclude from the vulgar experiment of betraying fishes with perfumed baites . chap. viii . of sapours . sect . i. the nature of sapours , the proper object of the taste , aristotle ( de sens . & sensil . cap. . ) concludes to be more easily cognoscible , than that of odours , visibles , or the objects of the other senses ; because as he praesumes , the sense of tasting in man , is more exquisite , than his smelling , sight , &c. whether his reason be not praecarious , we need not determine : but it too nearly concerns us to affirm , that the extreme slenderness of his doctrine , touching the essence and principles , of sapours as well in general as particular ; erected on that common imaginary base of immaterial qualities , hath given us just occasion to suspect the solidity of his inference or conclusion ; and left us cause to account that sentence , much more canonical , that things most manifest to the sense , often prove most obscure to the understanding . for , notwithstanding we have the demonstration of our sense , that , as he and all other philosophers unanimously assert , the object of the tasting , in general , is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , gustabile : yet doe his endeavours afford so dimme a light to our profounder inquisitions , as to leave us in the dark of insatisfaction , when we come to explore , what is the formal reason of a sapour ; what are the principles , or material and efficient cause thereof ; and what relation it bears unto , or manner how it affects the tongue , the prime and adaequate instrument of tasting . which that we may with due fulness and perspicuity declare , it behoveth us to invite your attention to a faithful summary of his speculations concerning that subject . aristotle , from whose text all the peripateticks have not receded insomuch as in a title , as to the particular under debate , fixeth the original of a sapour , in a certain contemperation of three prime elemental qualities ▪ viz. ( ) terrestrious siccity . ( ) aqueous humidity . ( ) heat . the two former as the material causes , the last as the efficient , to which , according to his custome , he consigns the masculine and determinative energy , as in this , so in all natural productions . the necessity or the concurrence of these three first qualities to the generation of a sapour in any concretion , he inferrs chiefly from hence ; that water , being in the purity or simplicity of its essence , absolutely insipid , if percolated through siccum terrestre , adust earth , doth alwayes acquire a sapidity , or savouriness , proportionate to the intense , or remiss adustion of the terrestrious material dissolved by , and incorporated to it self : as is commonly observable in fountains , which become impraegnate or tincted with the sapours of those veins of earth , through whose meanders and streights they have steered in their long subterraneous voyages ; and in all lixivial decoctions , or lees , which obtain a manifest saltness only by transcolation through ashes , the earthy and adust reliques of compound bodies , dissolved by fire . to which , he moreover addes , that because the contemperature may be various , according to greater or lesser proportion of either of the three ingredients ; and the aqueous humidum , united to the earthy siccum , hath its consistence sometimes participant of crassitude , sometime of tenuity : therefore are not all sapours alike , but different according to the several gradualities of their respective and specifical causes . and thus much in the general . to progress to the brief survey of particulars , it seems requisite that we observe ; that galen , avicenna , averrhoes , and most physitians after them , have conceived this theory of aristotles so firm and impraegnable , as they have thereon founded one of their pillars for the invention of remedies , and advanced rules for the conjectural investigation of the manifest faculties of medicaments , by the taste : to that end constituting eight differences , or generical distinctions of sapours , viz. ( ) acer , which affects the mouth and chiefly the tongue , with a certain acrimony and pungent ardor ; such as is eminently conspicuous in pepper , pellitory , euphorbium , cassea lignea , winterian bark , &c. it ariseth from a composition of tenuious , dry and hot parts , and cannot subsist in a subject of any other constitution . ( ) acid , or sharp , which likewise penetrateth and biteth the tongue , but with some constringency , and without any sense of heat : such as is deprehended in vinegre , juice of limons , citrons , woodsorrel , berberies , and in some malacotones and quinces . it results from a concretion of subtle and dry parts , either where the innate heat is resolved by some degree of putrefaction , as in vinegre : or where the innate heat is so small as to be inferior to cold , and that associated with extreme siccity ; as in juice of limons , &c. ( ) fat , or luscious , which sollicites the gusts neither with heat , nor acrimony ; but furrs and daubs the mouth with an unctuous lentor , or viscidity . such is remarkable in oyle olive , oyle of sweet almonds , wallnuts , in marrow , butter , and the fat 's of beasts , which have no rancidity , either acquired by antiquity , or natural , such as is perceivable in the fat of lions , wolves , and tigers : and in all mucilaginous plants , as in althaea and white lilly roots , &c. this hath its production from a thin aereal matter , temperate in heat and cold . ( ) salt , which doth not much calefie , but with a sharp and penetring siccity bite the tongue ; as is observed in the degustation of common salt , nitre , and among vegetables chiefly in rock sampier . this sapour is also sensible in all chymical salts , extracted from bodies by the sequestrating activity of fire , cinefying their dry and terrestrious remains : nor is there any compound in nature , from which pyrotechny may not extract the calx or proper salt thereof , discernable by the taste . and therefore it is manifest , that all saltness subsisteth in a matter , whose principal ingredients , heat and siccity are equal . ( ) austere , which being moderately adstringent , doth with some asperity coarctate the particles of the tongue ; and therefore according to the judgment of the pallate , it seems dry and cooling . this is more properly called the crude sapour , as being peculiar to all fruits during their immaturity ; as is generally noted in the juice of unripe grapes , green apricocks , pears , apples , medlars , porcellane , &c. the substance wherein it consisteth , must be equally participant of earth and water , but where cold hath the upper hand of heat . ( ) sweet , which being not offensive by the unevenness or exuperance of any quality , affects the sense with suavity or delight . such every man knows to be in sugar , honey , liquorice , iujubes , dates , figgs , and in most fruits after their maturity : as also in manna , and , in some degree , in milk. ( ) bitter , the contrary to sweet , which offending by the asperity and tenuity of its parts , doth in a manner corrade and divell the sensory . this superlatively discovers it self in aloes , coloquyntida , rhubarb , wormwood , the lesser centaury , bitter almonds , and the galls of animals . the matter of it is crass and terrene , but adust by immoderate heat ; and hence that galenical axiome , omne amarum est calidum & siccum . ( ) acerb , or sower , which bordereth upon the austere or pontick sapour , being distinguishable from it , only by a greater ingratefulness to the sense ; for it more constringeth and exasperateth all parts of the mouth , and so seems more exsiccative and refrigerative . it is prodigally perceived in the rind of pomegranates , galls , sumach , cypress nuts , the bark of oak , the cups of achorns , &c. it s residence is alwayes in a composition totally terrene and drye , whose languid heat is subdued to inactivity by the superior force of its antagonist , cold. to these some modern physitians ( to whom that mystagogus or priest of the arabian oracles , fernelius , seems to have been the coryphaeus ) have superadded a ninth sapour , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , the fatuous ; which affecting the sense with no impression , is indeed no sapour , but rather the privation of all sapidity . to this heteroclite are commonly referred the several species of bread corn , gourds , citrals , cucumbers , &c. whose materials though crass , are not yet terrene , dry and adstrictive ; but diluted with a plentiful portion of aqueous moisture , not exquisitely permixt , because of the small allowance of heat to their composition . now ( to pass from the faithful abridgment to the aequitable examen of this doctrine , of such sacred estimation in the schools . ) though the enquiries of most have steered this course , directed by the chart of aristotle , and attempted the deduction of all sapours from primitive qualities : yet have they missed the cape of truth . for , as scaliger ( in lib. de plantis . ) excellently argues , we may as safely derive life , sense , increment , voluntary motion , nay risibility and intellection ( actions flowing from forms more noble and semi-divine ) from elements immediately , as sapours from their first qualities : unless it can be first evinced , that each element hath some sapour actually inexistent ; which but barely to suppose , is an absurdity gross enough to degrade the owner from the dignity of a physiologist forever , and openly repugnant to the fundaments of the aristotelean philosophy . to which argument of scaligers , we shall superadd this weighty exception of our own ; that according to the hypothesis of first elemental qualities , it is absolutely impossible to explicate the causes of that so great diversity of tasts not only among animals of different species , but individuals of the same species ; of which we shall discourse more expresly in opportunity . wheref●re we account it both more honourable and satisfactory , to incline rather to that laudable opinion of the chymist , whose flames have so farr enlightned our reason , as to shew , that the primary cause of s●pours doth consist in salt ; because all pyrotechnical dissolutions seem to establish that axiome , sal est primum sapidum & gustabile , & omnia quae saporem habent , eam propter salem habent ; ubicunque enim s●por deprehenditur , ibi sal est , & ubicunque sal , ibi sapor : as the judiciou● sennertus hath observed ( de consensu chymicorum cum galenic . cap. . ) and lucius grillus hath copiously and solidly declared in that elaborate treatise of his , de sapore amaro & dulci , to which we remit the farther curious . but , if we would anatomize the heart of this subject , and establish a more exact theory of the first principles of a sapour ; we must consult the oracles of democritus and plato , which tell us in short , that all sapours arise from the minute particles of bodies , of such determinate figures and contextures , as being applied to the tongue , they naturally produce that affection therein , which we call gustation , or tasting . of democritus●uctority ●uctority , in this point , no man can justly doubt while aristotle ( de sens . & sensil . cap. . ) avoucheth that he [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] did referr sapours to figures : and theophrastus , in a more ample descant upon the text , affirms that he defined the particular sorts of figures , which constitute the particular species of sapours ; in these words , rotundas esse , congruaque mole figuras , quae dulcem faciant ; magnâ figurâ , quae acerbum ; multangulâ miniméque orbiculari , quae acrem ; angulatâ distortâ , quae salsum ; rotundâ , laevi , distortâ , quae amarum ; tenui , rotund● , parv● , quae pinguem and , what was platoes persuasion , concerning the same argument , himsef most perspicuously explains ( in timaeo ) where he in short adscribes the production of all sapours [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] to asperity and laevity : and distinguishing all sapours into two general orders , the first a pleasant or sweet sort , the other an unpleasant , which runs up into several branches ( for as it stands opposed to sweet , it is either bitter , or salt , or acid , or acerb , or acer , or austere , &c. ) he derives the first kind from hence , that the sapid object consists of particles so configurate , that effused upon the organ of tasting , and entering the small pores or receptaries thereof , they become symbolical or correspondent to its small particles in figure and contexture , and so affect it gently , evenly , and concordantly ; and the latter from hence , that the sapid object is composed of such particles , as have their figures and contexture so disproportionate and incommensurable to the pores and particles of the tongue , that invading it and entering its contexture , they exasperate , corrade and offend the same . and hence was it , that lucretius seems to have borrowed his , ut facilè agnosc●s , è laevibus atque rotundis esse ea , quae sensus jucunde tangere possunt : at contra , quae amara , atque aspera cunque videntur , haec magis hamalis inter se cumque teneri ; proptereaque solere vias rescindere nostris sensibus , introituque suo perrumpere corpus . and this is the opinion to which we have espoused our constant assent , as well upon the obligation of those reasons formerly alledged , in our original of qualities ; as upon this important consideration , that no other hypothesis can afford a satisfactory reason either of manner of the sapours moving and affecting the sensory , or why there is such infinite variety of tasts not only among animals of different species , but even in individuals of the same species , and particularly in men , among whom millions are found , who delight in wormwood , and abhorr sugar ; some that feast their pallates with aloes ; others that think their mouths quite out of taste , unless they be ruminating the leaves of tobacco ; nay , we have known a noble person of our own nation , who had so singular a pallate , that whenever he took a purging potion , would swallow it down by spoonfuls , as judging the pleasure too great to be shortned by a hasty draught , and when t was wholly exhausted , would wish himself a ruminating animal , that so he might taste it over and over , as if philoxenus wish for a cranes neck were too short to reach the height of so desireable a delight ; and another , who would not be persuaded but the forbidden fruit was a coloquyntida apple , because he thought the taste of that the most ambrosiack of all others . but , conceding with democritus and plato , that the variety of sapours is caused meerly by the diversity of impressions on the spongy substance of the tongue , respective to the various figures and contextures of the minute particles of bodies applied thereto , and by the salivous moisture thereof so admitted into the pores , as sensibly to affect it : we say , conceding this , we soon may solve this dissimilitude of tastes , only by saying , that because the contexture of the particles of the tongue of one man , is different from that of the particles of another ; therefore doth one delight in the savor of one thing , the other of another : every man being of necessity most pleased with the taste of that , whose particles in figure and contexture are most symbolical or correspondent to the figures and contexture of the particles of his tongue ; and è contra . to which we shall only add , that the reason why to men in feavers the sweetest things seem bitter , is only this ; that the contexture of the particles of the tongue being altered , as well by the intense heat of the feaver , as the infusion of a bilious humour into the pores thereof : those things , whose particles being formerly accommodate , appeared in the species of sweetness , are now become asymbolical and inconvenient to the particles of the tongue , and therefore appear bitter . nor is aristotles reprehension of democritus , of weight enough to counter-encline our judgment ; his chief objections being rather sophistical , than solid , and so no sooner urged than dissolved . his first is of this importance ; if the particles of sapid objects were figurate , according to democritus assumption , then would the sight , as a sense far more acute in perception , deprehend their various figures rather than the taste : but the sight doth not discern them ; ergo. which is soon expeded , by answering , that it is not in the jurisdiction of one sense to judge of objects proper to another ; nor is the quaestion about the figures , as they are in themselves , i. e. without relation to the sense , but as they produce such a determinate effect on the sensory , of which the tasting is the sole and proper criterion . for qualities are to be reputed , not so much absolute and constant realities , as simple and relative apparencies , whose specification consisteth in a certain modification of the first general matter , respective to that distinct affection they introduce upon this or that particular sense , when thereby actually deprehended . his second of this . insomuch as there is a contrariety among sensible objects of all kinds ; but none among figures , according to that universally embraced canon , figuris nihil esse contrarium : if the diversity of sapours were derivative from the diversity of figures , then would there be no cont●●riety betwixt sapours ; but sweet and bitter are contraries ; ergo. which is soon detected to subsist upon a principle meerly precarious ; for we are y●t ignorant of any reason , why we should not account an acute figure the contrary to an obtuse ; a gibbous the opposite to a plane ; a smooth the antagonist to a rough ; an angular the antitheton to a sphere , &c. his third , and most considerable , of this . because the variety of figures is infinite , at least , inassignable ; therefore would the variety of sapours , if their distinct species were dependent on the distinct species of figures , be aequally infinite : but all the observable differences of sa●ours exceed not the number of eight , at most ; ergo. answer ; should we allow aristotles distinction of sapours to be genuine : yet would it not follow , that therefore there are no more specifical subdivisions of each genus ; because from the various commistions of those eight generical differences one among another , an incomprehensible variety of distinct sapours may be produced . besides , is not that sweetness , which the tongue perceives in hony ; manifestly different from that of milk ? that of sugar easily discernable from both ? that of canary sack different from that of malago ? that of an apple distinguishable from that of a plumm ? that of flesh clearly distinct from all the rest ? yet doth that genus of sweet comprehend them all . on the other side , is the amaritude of aloes , coloquyntida , rhubarb , wormwood , &c. one and the same ? or the acerbity of cherries , prunes , medlars , &c. identical ? no man , certainly , dares affirm it . why therefore should we not write our names in the catalogue of those , who conceive as great variety of tastes , as there is of sapid objects in nature . or , since the experiments of chymistry have made it probable , that all sapours derive themselves from salts , as from their primary cause ; why may we not concede so many several sorts of salts , and so many possible commistions of them , as may suffice to the production of an incomprehensible variety of sapours ? and this gives us occasion to observe , that nature seems to have furnished the tonge with a certain peculiar moisture , chiefly to this end , that it might have a general menstruum , or dissolvent of its own , for the eduction of those salts from hard and drye bodies , and the imbibition of them into its spongy substance , that so it might deprehend and discern them . chap. ix . of rarity , density , perspicuity , opacity . sect . i. having thus steered through the deepest difficulties touching the proper objects of the other senses , the chart of method directs us in our next course to profound the particular natures of all those qualities , which belong to the apprehensive jurisdiction of the sense of touching , either immediately , or relatively . but , before we weigh anchor , that we may avoid the quicksands of too general apprehensions , and draw a map or scheme of all the heads of our intended enquiries ; tha● so we may praepare the mind of our reader to accompany us the more easily and smoothly : it is requisite that we advertise , ( ) that the attribute of touching is sometimes in common to all bodies , 〈◊〉 well inanimate , as animate , when their superficies or extremes ar● contingent ; according to that antithesis of lucretius , tactus corporibus cunctis , intactus inani . sometimes in common to all sens●● , insomuch as all sensation is a kind of touching , it being necessa●● , that either the object it self immediately , or some substantial em●nation from it , be contingent to the sensory ; as we have apodictically declared in our praecedent considerations of visible , audible , odo●●ble , and gustable species . sometimes ( and in praesent ) proper to th● sense of touching in animals ; which , however it extend to the per●●ption of objects , in number manifold , in nature various and frequ●●●ly even repugnant ( whereupon some philosophers have contuma●iously contended for a plurality of animal touchings ; others gone so high as to constitute as many distinct powers of touching , as th●re are [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] differences and 〈◊〉 of conditions in tangibles ) doth yet apprehend them all 〈◊〉 one and the same common reason , and determinate qualification , after the same manner , as the sight discernes white , black , red , green , &c. all sub communi coloris ratione , in the common capacity of colours . and this is that fertile sense , to whose proper incitement we owe our generation ; for , had not the eternal providence endowed the organs official to the recruit of mankind , with a most exquisite and delicate sense of touching , the titillation whereof transports a man beyond the severity of his reason , and charmes him to the act of carnality ; doubtless , the deluge had been spared ; for the first age had been the last , and humanity been lost in the grave , as well as innocence in the fall of our first parents . quis enim ▪ per deum immortalem , concubitum , rem adeo faedam , solicitaret , amplexaretur , ei indulgeret ? quo vultu divinum illud animal plenum rationis & consilii , quem vocamus hominem , obsaenas mulierum partes , tot sordibus conspurcatus attrectaret , nisi incredibili voluptatis aestro percita essent genetalia ? and let us but abate the temptation of this sense , and libidinous invitement of it praeambulous to the act of congression ; and we shall soon confess that so magnified delight of sensuality , to be no other than what the noblest of stoicks , marcus antoninus defined it , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , but the attrition of a base entrail , and the excretion of a little snivel , with a kind of convulsion , as hippocrates describes it , this is that fidus achates , or constant friend , that conserves us in our first life , which we spend in the dark prison of the womb ; ushers us into this , which our improvidence trifles away for the most part on the blandishments of sensual appetite ; and never forsakes us , till death hath translated us into an eternal one . for when all our other unconstant senses perish , this faithful one doth not abandon us , but at that moment , which determines our mortality . whence aristotle drew that prognostick ( de anim. lib. . cap. . ) that if any animal be once deprived of the sense of touching , death must immediately ensue ; for neither is it possible ( saith he ) that any living creature should want this sense , nor to the being of it is it necessary that it have any other sense beside this . in a word , this is that persuasive sense , and whose testimony the wary apostle chose to part with his infidelity , and to conclude the presence of his revived lord. that painful sense , on the victory of whose torments the patient souls of martyrs have ascended above their faith . that virtual and medical sense , by which the great physician of diseased nature , was pleased to restore sight to the blind , agility to the lame , hearing to the deaf ; to extinguish the feaver in peters mother-in-law , stop the inveterate issue in his haemorhoidal client ; unlock the adamantine gates of death , and restore the widows son from the total privation , to the perfect habit of life . ( ) that some qualities are sensible to the touch , which yet are common to the perception of other senses also ; for no scholler can be ignorant of that division of sensibles into common and proper ; and that among the common are reckoned motion , quiet , number , figure , and magnitude , according to the list of aristotle ( de anim. cap. . ) ( and principally ) that the qualities of concretions , either commonly or properly appertaining to the sense of touching , are to be considered in their several relations to the principles on which they depend . first , some result from the universal matter , atomes , in this respect , that they intercept inanity , or space betwixt them ; and of this original are rarity and density , with their consequents , perspicuity and opacity . secondly , some depend on the common materials , in this respect , that they are endowed with their three essential proprieties , magnitude , figure , motion : and that either singly , or conjunctly . ( ) singly , and either from their magnitude alone ; of which order is the magnitude o● quantity of any concretion ; and the consequents thereof , subtility and hebetude : or from their figure alone , of which sort is the figure of every thing ; and the consequents thereof , smoothness and asperity , &c. or only from their motiv● virtue , of which kind is the motive force inhaerent in all things in th● general , and that which assisteth and perfecteth the same in most things , the habit of motion , and particularly gravity and levity . ( ) conjunc●ly , from them all ; of which production are those commonly called the ●our first qualities , heat , cold , dryness , moysture ; as also those which ●r● deduced from them , as hardness , softness , flexility , ductility : and all others of which aristotle so copiously ( but scarce pertinently ) treateth in his fourth book of meteors : and lastly , those by vulgar physiologist named occult qualities , which are also derivative from atoms , in res●●ct of their three essential proprieties ; and among these the most eminent and generally celebrated , is the attractive virtue of the loadstone . now on each of these we intend to bestowe particular speculation , allowing it the ●●me order , which it holds in this scheme , which seems to be only a faithful transsumpt of the method of nature : and we shall begin at rarity and density . ( ) because nothing can be generated but of atoms commixt , and that commixture cannot be without more or less of the inane space in●●rcepted among their small masses ; so that if much of the inane space 〈◊〉 intercepted among them , the concretion must be rare , if little , dense , of meer necessity : ( ) because , the four first reputed qualities , heat , cold , dryness , moysture , are posterior to rarity and density , as appears by that of aristotle ( physic . cap. . ) where , according to the interpretation of pacius , he intimates , that heat and cold , hardness and sof●ness are certain kindes of rarity and density ; and therefore we are ●o set forth from them , as the more common in nature , and consequently the more necessary to be known , a generalioribus enim , tanquam notioribus ad minus generalia procedendum , is the advice of arist. ( physic . . cap. . ) sect . ii. concerning the immediate causes of rarity and density in bodies , divers conceptions are delivered by philosophers . ( ) some , observing that rare bodies generally are less , and dense more ponderous , and that the division of a body into small parts , doth usually make it less swift in its descent through aer or water , than while it was intire ; have thereupon determined the reason of rarity to consist in the actual division of a body into many small parts : and , on the contrary , that of density to consist in the coadunation or compaction of many small parts into one great continued mass . but , these considered not , that chrystal is not more rare , though less weighty ( proportionately ) than a diamond : nor that the velocity of bodies descending , doth not encrease in proportion to the difference of their several densities , as their inadvertency made them praesume ; there being sundry other causes , besides the density of a body , assignable to its greater velocity of motion in descent , as the heroical pen of galileo hath clearly demonstrated ( in . dialog . de motu . ) and our selves shall professedly evince in convenient place . ( ) others , indecently leaping from physical to metaphysical speculations , and imagining the substance of a body to be a thing really dist●nct from the quantity thereof ; have derived rarity and density from the ●●veral proportions , which quantity hath to its substance ; as if in rarefaction a body did receive no mutation of figure , but an augmentation , and in condensation a diminution of its quantity . but the excessive subtility , or rather absolute incomprehensibility of this distinction , doth evidently confess it to be meerly chimerical , as we have formerly intimated , in our discourse concerning the proper and genuine notions of corporiety and inanity . ( ) a third sort there are , who having detected the incompetency of the first opinion , and absolute unintelligibility of the second ; judiciously desume the more or less of rarity in any body , from the more or less of vacuity intercepted among the parts thereof ; and on the contrary , the more or less of density from the greater or less exclusion of inanity , by the reduction of the parts of a body to mutual contingency . and this is that opinion , which only hath subjugated our judgement , and which seems worthy our best patronage : in regard not only of its sufficiency to explicate all the various apparences among bodies , resulting from their several differences in rarity and density ; but also of its exuperance of reason above the f●rst , and of intelligibility above the second ; it being the duety of a philosopher , always to prefer perspicuity to obscurity , plain and genuine notions to such as are abstracted not farther from matter , than all possibility of comprehension . according to this hypothesis , therefore , of vacuities interspersed ( of which ●pecurus seems to have been the author ) we understand , and dare define a rare body to be such , as obtaining little of matter , possesseth much of place ; and on the contrary , a dense one to be that , which obtaining much of matter , possesseth little of place : intending by place , all that space circumscribed by the superfice of the ambient , such as is the space included betwixt the sides , or in the concave of a vessel . for , supposing any determinate space to be one while possessed by aer alone , another while by water alone ; the aer therein contained cannot be said to be rare , but only because though it hath much less of matter , or substance , yet it takes up as much of space , or room as the water : nor the water to be dense , but only because though it hath much more of matter , yet doth it take up no more of space , than the aer . whence it is purely consequent , that if we conceive that water to be rarified into aer , and that aer to be condensed into water ; the aer made of the water re●ified , must replenish a vessel of capacity not only ten-fold , as aristotle inconsiderately conjectured , but a hundred-fold greater , as mersennus by stalick experiments hath demonstrated : and transpositively , the water made by the aer condensed , must be received in a vessel of capacity an hundred-fold less ; when yet in that greater mass of aer , there can be no more of matter , or quantity , than was in that smaller mass of water , before its rare●action ; nor in that smaller mass of water less of matter , or quantity , than was in that greater mass of aer , before its condensation . evident it is , therefore , that by those , contrary motions of rarifaction and condensation , a body doth suffer no more than the meer mutation of its figure , or the diffusion and contraction of its parts : its quantity admitting no augment●tion in the one , nor diminution of the other . this being apodictical , the sole difficulty that requires our enodation , is only this ; whether a rare body possessing a greater space , than a dense , proportion●tely to its quantity , doth so possess all that space circumscribed by its superfice , as to replenish all and every the least particle thereof , not leaving any space or spaces , however exile , unreplenisht with some adaequate particle of its matter ? or whether there are not some small parts of space , in●●rmixt among its diffused or mutually incontingent particles , in which no particles of its matter are included , and so there remain small vacuola , or empty spaces , such as we have formerly more than twi●e described , in our chapter of a disseminate vacuity in nature ? and this descends into another doubt , whose clear solution is of so much importance , as richly to compensate our most anxious enquirie ; viz. whether rarity be caused from the interception of much inanity , when the parts of a body , formerly adunate , are separated each from other ( at least , in some points of their superfices ) and so the body become so much more rare , by how much the more , or more ample empty spaces are intercepted among its incontingent particles : or wheth●r density and rarity depend on any other possible causes besides th●s , i. e. without the intermistion of inane spaces among ●he 〈◊〉 of bodies ? and this we conceive to be the whole and true state of that controversie , which hath so perplexed the minds of many the most eminent philosophers in the world . that the rarity and density of bodies can arise from no other cause immediately , but the more or less of inanity intercepted among their particles ; may be thus demonstrated . if in a rare body there be admitted no vacuola , or small empty spaces , but it be assumed , that the particles of matter are adaequate both in number and dimensions to the particles of space , wherein it is contained ; then must it necessarily follow , that in condensation many particles of matter must be reduced into one particle space , which before condensation was adaequate onely to one particle of matter : and , on the contrary ; in rarefaction , one and the same particle of matter must possess many of space , each whereof , before rarefaction , was in dimensions fully respondent thereto . for example ; in aer condensed into water , an hundred particles of aer must be reduced into one particle of space : and in water rarified into aer , one particle of the matter of water must possess an hundred particles of space . again , according to the assumption of no vacuity , since in a vessel replete with aer , the parts of aer must be equal in number and dimensions to the parts of space , thereby circumscribed , none the least particle of space being admitted to be inane ; if you fill the same vessel with water , or lead , or gold , it must follow , that the parts of the matter of aer , and the parts of the matter of water , lead , or gold , shall be equal in number , because quae sunt uni tertio aequalia ; aequalia sunt etiam inter se : and if so , needs must aer be aequally dense with water , lead , or gold , which all men allow to be the most dense and compact body in nature in regard it transcends all others in weight and difficulty of solution , or division ; ( ) all bodies in the universe must be equally dense , or equally rare ; ( ) and so nothing can be capable of condensation or rarefaction . the least of which unconcealable absurdities , ( not to enumerate any others of those many that depend on the same concession of an absolute plenitude , or no vacuity ) is great enough to render those heads , which have laboured to destroy the vacuola of epicurus , strongly suspected of incogitancy , if not of stupidity . t were good manners in us to praesume , that no man can be so facile , as to conceive , that aristotle hath prevented these exceptions , by that distinction of his , de actu & potentia : but , because praejudice may do much , we judge it expedient a while to insist upon the examination of the importance and congruity thereof . he ratiocinates ( ▪ physic . cap. . ) that the matter of contraries , e. g. of heat and cold , rarity and density is one and the same ; so that as the same matter is one while actually hot another while actually cold , because it is both hot and cold potentially : so is one and the same matter now actually rare , now actually dense , because it is both rare and dense potentially . but , in strictness of logick , all that this argument enforceth , is only that the same matter is capable of rarefaction and condensation ; which no man ever disputed . the quaestion is , whether the same matter , when actually rare , hath its parts dissociated and diffused into a greater space , than what they possessed while it was onely potentially rare , and that without the intermixture of inanity among them ? and all that can be collected from his discourses touching that , is no more than this ; that as a matter or substance actually hot , doth become more hot , without the emersion , or accession of any new part , which was not actually hot before : so likewise doth the same matter actually extense , become more extense , without the emersion , or accession of any new part , which was not actually extense before . but this arrow was shot at random , not directly to the mark , nor hath it attained the difficulty ▪ for the quaestion again is not , whether in rarefaction , any part of the matter were not formerly extense : but , whether that matter , which was formerly extense , can be made more extense without the dissociation of its particles ▪ and whether the particles of it can be actually dissociated , without the interception of inanity among them ? besides , his comparison is as incongruous , as his argument is weak ; for ( ) his assumption concerning heat is not only precarious , but false , as shall be demonst●●ted , in suo loco : ( ) were it true , yet doth that part of matter , which is actually hot , remain indivulse or indistracted ; otherwise than a part of matter , which being actually extense , becomes more extense , and therefore the analogy faileth . in conclusion , to mend the matter , he recurrs to that similitude of a circle , which though contracted into a less , hath yet none of its parts more incurvate than they were before : but , alas the quaestion still remains untoucht , ●nd ( that we may not stay to impeach him of indecorum , in making an ●ndecent transition from a physical to a mathematical subject ; contrary to his own dialectical institutes ) his similitude will bear no more of inference but only this , that a thing may be made more dense , which is 〈◊〉 and lax ; which is impertinently disputed , when all men concede it . the ad●ocates of aristotle generally alleage in his defense , that he supposed a certain aethereal , or as some have called it , animal substance , which inexistent in all bodies , doth replenish their pores , and more espe●●●lly if their contexture be rare ; and that when a dense bodie is rarified , there are no small inane spaces intercepted among its dissociated parti●les , but that the spaces betwixt them are immediately possessed by that subtile aethereal substance : and that when a rare body is condensed , th●t aethereal substance , which did replenish its pores , is excluded . but th●● supposition , though it come neerer to the quaestion , or center of the difficulty , is yet far short of solving it . for , take we ( for example ) ● c●b●cal foot of aer , and insomuch as the substance of the aer is more 〈◊〉 , or less exile , than the substance of the supposed aether , therefore 〈◊〉 it consist of fewer particles , than the aether : and upon consequence ▪ 〈◊〉 the whole cubical foot of aer there are not more particles of matte● 〈◊〉 the aereal and aethereal ones being conjoyned , than if it consisted o●●y of aereal particles . now we enquire of aristotles champions , whether or no in that cubical foot consisting of the aggregate of both sorts of particles , there are as many particles of matter , as are in a cubical foot of water , lead , or gold ▪ the affirmative is more than they dare own ; nor can they deny , but that the space possessed by one foot containeth as many small parts of space , respondent to the particles of matter , as the other : and if so , must not there be in the foot of aer , many particles of space , which are possessed neither by the aereal nor aethereal particles , and are not those unpossessed particles of space absolutely empty ? if you undertake the negative , you insnare your self in this absurdity , that the particles of a cubical foot of aer and aether conjoyned , must be equal in number to the particles of a cubical foot of water , lead , or gold. the difficulty of understanding the formal and immediate reason of rarity and density in bodies , by that so popularly applauded hypothesis of an aethereal substance ( imagined to maintain an absolute plenitude , and so a continuity through the whole vast body of nature ) being thus evinced ; let us a while consider , how easily even the meanest capacity may comprehend the full nature of those primary and eminent affections , from the concession of small vacuities . we have formerly explicated the matter , by the convenient similitude of an heap of corn , or sand ; which being lightly and gently poured into a vessel , takes up more room then when prest down : and we shall yet more facilitate the conception thereof by another simile , somewhat more praegnant , because more analogous . when a fleece , or lock of wool is deduced , or distended , we say , it is made more rare ; and when compressed , more dense : now the rarity thereof consisteth only in this , that the hairs , which were formerly more consociate , united , or at closer order among themselves , are dissociated , dis-united , or reduced to more open order , and the spaces betwixt them , become either more , or larger , in which no particle of wool is contained : and on the contrary , the density thereof consisteth onely in this , that the particles or hairs , which were before more dissociated , or at open order , are by compression brought to more vicinity , or to closer order , and the spaces betwixt them become fewer and lesser . and thus are we to conceive , how the same matter , without augmentation or diminution of quantity , may be now rarified into aer , and anon condensed into water ; for , instead of the hairs in the fleece of wool , we need only put the particles of the matter , which in rarifaction are dissociated , in condensation coadunated . and this conception may be extended also to a spunge , flaxe , or any other porous and lax bodie ▪ because they are capable of expansion and contraction onely in this respect , that the small spaces intercepted in the incontiguities or distances of their particles , are now enlarged , now contracted . we confess , this similitude is not adaequate in all points , there being this difference , that when a fleece of wool is expansed , the ambient aer doth instantly insinuate into the small spaces intercepted betwixt the dissociated particles of it , and so possess them ▪ but ▪ nothing of aer , or aether , or other substance whatever doth insinuate it self into the small spaces intercepted betwixt the dissociated particles or aer ▪ or water , when either of them is rarified : we say , notwithstanding this disparity , yet doth it hold thus far good and quadrant , that as nothing of wool possesseth those spaces , which would therefore remain absolutely empty , in case the sociable aer did not instantly succeed in possession of them ; so , since the parts of the matter of water are expansed or dissociated after the same manner , as are the hairs of wool , and after the same manner contracted or united ; and certain small loculaments are likewise intercepted betwixt the particles of that matter , in which nothing of water can be contained , during the state of rarifaction , and which no other substance can be proved to possess ; it must thence follow , that those deserted small spaces , or loculaments remain absolutely empty . and more than that , our similitude is not concerned to impart . but , that we may make some farther advantage thereof , we observe ; that as when a fleece of wooll is expansed , it is of a greater circumference , and so includes a greater capacity therein , than when it is compressed ; not that the single hairs thereof take up a greater space in that capacity , for no haire can possess more space , than its proper bulk requires , but because the inane spaces or loculaments intercepted betwixt their divisions are enlarged : exactly so , when the same matter is now rarified into aer , anon condensed into water , the circumference thereof becomes greater and less , and the capacity included in that circumference is augmented and diminished accordingly ; not that the single particles of the matter possess a greater part of that capacity in the state of rarifaction , th●● in that of condensation , because no particle can possess more of space than what is adaequate to its dimensions ; but only because the inane spaces intercepted betwixt their divisions are more ample in one case , than in the other . and hence it is purely consequent , that the matter of a body rarified can not be justly affirmed to possess more of true or proper place , than the matter of the same body condensed ; though , when we speak according to the customary dialect of the vulgar , we say , that a body rarified doth possess more of space , than when condensed : insomuch as under the terme place is comprehended all that capacity circumscribed by the extremes or superfice of a body ; and to the matter , or body it self are attributed not onely the small spaces possessed by the particles thereof , but also all those inane spaces interjacent among them , just as by the word city , every man understands not only the dwelling houses , churches , castles , and other aedifices , but also all the streets , piazzaes , church-yards , gardens , and other void places contained within the walls of it . and in this sense onely are our praecedent definitions of a rare , and dense body to be accepted . the reasons of rarity and density thus evidently commonstrated , the pleasantness of contemplation would invite us to advance to the examination of the several proportions of gravity and levity among bodies , respective to their particular differences in density and rarity ; the several ways of rarifying and condensing aer and water ; and the means of attaining the certain weights of each , in the several rates , or degrees of their rarifaction and condensation ; according to the evidence of aerostatick and hydrostatick experiments : but in regard these things are not directly pertinent to our present scope and institution , and that galilaeus and mersennus have enriched the world with excellent disquisitions upon each of those sublime theorems ; we conceive ourselves more excusable for the omission , than we should have been for the consideration of them , in this place . however , we ask leave to make a short excursion upon that problem , of so great importance to those , who exercise their ingenuity in either hydraulick , or pneumatick ▪ mechanicks : viz. whether may aer be rarified as much as condensed ; or whether it be capable of rarifaction and condensation to the same rate , or in the same proportion ? that common oracle , for the solution of problems of this abstruse nature , experience hath assured , that aer , may be rarified to so great a height , in red-hot aeolipiles , or hermetical bellows , that the part of aer formerly contained therein , before rarifaction , will totally fill an aeolipile upon extreme rarifaction thereof . for , mersennus , using an aeolipile , which being cold , would receive exactly ounces , one drachm and an half ; and when hot , would suck in only ounces : found , that the whole quantity of aer ignified , and replenishing the same aeolipile , when glowing hot , being reduced to its natural state , did possess only the . part of the whole capacity , which was due to the drachm and half of water . we say , upon extreme rarifaction ; because this seems to be the highest rate , to which any rarifaction can attain , in regard the metal of the aeolipile can endure no more violence of the fire , without fusion . as for the tax , or rate of its utmost condensation ; though many are persuaded , that aer cannot be reduced , by condensation , to more than a third part of that space , which it possesseth in its natural state ; because they have observed , that water infused into a vessel of three heminae , doth not exceed two heminae , in regard of the aer remaining within : yet certain it is , that aer may be condensed to a far higher proportion . for , experience also confirms , that into the chamber of a wind-gun ( of usual dimensions ) aer may be intruded , to the weight of a drachm , or sixty grains : and that in that capacity , which contains only an ounce of water , it may be so included , as that yet a greater proportion of aer may be injected into it . now , therefore , insomuch as the aer in ●ersennus his aeolipile amounts to four grains ( at least ) or sixe ( at most ) which number is ten times multiplied in sixty ; and that the concave of the aeolipile is to the concave of the pipe of the wind-gun , in proportion sesquialteral : by computation it appears , that the aer condensed in the chamber of the wind-gun must be sufficient to fill the aeolipile ten times over , or the same chamber times over , if restored to its natural tenour . and hereupon we may safely conclude , that aer may be compressed in a wind-gun , to such a rate , as to be contained in a space times less , than what it possessed during its natural laxity ; and that by the force only of a mans hand , ramming down the embol●s , or charging iron : which force being capable of quadruplication , the aer may be reduced into a space subquadruple to the former . if so , the rate of the possible condensation of aer , will not come much short of that of its extreme rarefaction : at least , if a quadruple force be sufficient to a quadruple condensation ; and aer be capable of a quadruple compression : both which are difficulties not easily determinable . sect . iii. perspicuity and opacity we well know to be qualities not praecisely conformable to the laws of rarity and density ; yet , insomuch as it is for the most part found true ( caeteris paribus ) that every concretion is so much more perspicuous , by how much the more rare ; and è contra , so much the more opace , by how much more dense ; and that the reason of perspicuity can hardly be understood , but by assuming certain small vacuities in the body interposed betwixt the object and the eye , such as may give free passage to the visible species ; nor that of opacity , but by conceding a certain corpulency to the space or thing therein interposed , such as may terminate the sight : therefore cannot this place be judged incompetent , to the consideration of their severall originals . by a perspicuum [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] we suppose , that every man understands that body , or space , which though interposed betwixt the eye and a lucid , or colorate object , doth nevertheless not hinder the transition of the visible species from it to the eye : and by an opacum ; that which obstructing the passage of the visible species , terminates the sight in it self . we suppose also , that ( according to our praecedent theory ) the species visible consist of certain corporeal rayes emitted from the object , in direct lines toward the eye ; and that where the medium , or interjacent space is free , those rayes are delated through it without impediment ; but , where the space is praepossessed by any solid or impervious substance , they are repercussed from it toward their original , the object . and hence we inferr , that because the total freedom of their transmission depends only upon the total inanity of the space intermediate ; and so the more or less of freedome trajective depends upon the more or less of inanity in the space intermediate : therefore must every concretion be so much more perspicuous , by how much the more , and more ample inane spaces it hath intercepted among its component particles ; which permit the rayes freely to continue on their progress home to the eye . this we affirm not universally , but under the due limitation of a caeteris paribus , as we have formerly hinted . because , notwithstanding a piece of lawn is more or less perspicuous , according as the contexture of its threads is more or less rare ; and the aer in like manner is more or less pellucid , according as it is perfused with more or fewer vapours : yet do we not want bodies , as paper , sponges , &c. which though more then meanly rare , are nevertheless indiaphanous ; and on the contrary , we see many bodies , sufficiently dense , as horn , muscovy-glass , common glass , &c. which are yet considerably diaphanous . now , that you may clearly comprehend the cause of this difference , be pleased to hold your right hand before your eye , with your fingers somewhat distant each from other ; and then looking at some object , you may behold it through the chinks or intervals of your fingers : this done , put your left hand also over your right , so as the fingers of it may be in the same position with the former ; and then may you perceive the object , at least as many parts of it as before . but , if you dispose the fingers of your left hand so as to fill up the spaces or intervals betwixt those of your right ; the object shall be wholly eclipsed . thus also , if you look at an object through a lawn , or hair sieve , and then put another sieve over that , so as the holes or pores of the second be parallel to those of the first ; you may as plainly discern it through both as one : but , if the twists of the second sieve be objected to the pores of the first , then shall you perceive no part of the object , at least so much the fewer parts , by how much greater a number of pores in the first are confronted by threads in the second . and hence you cannot but acknowledge that the liberty of inspection doth depend immediately and necessarily upon the inanity of the pores ; the impediment of it upon the bodies that hinder the trajection of the rayes emitted from the object : and yet that to diaphanity is required a certain orderly and alternate position of the pores and bodies , or particles . this considered , it is manifest , that the reason why glass , though much more dense , is yet much more perspicuous than paper , is only this ; that the contexture of the small filaments , composing the substance of paper , is so confused , as that the pores that are open on one side or superfice thereof , are not continued through to the other , but variously intercepted with cross-running filaments : as is more sensible in the co●texture of a spunge , whose holes are not continued quite thorow , but determined at half way , ( some more , some less ) so that frequently the bottome of one hole is the cover of another , as the cells in a hony-comb : but , glass , in regard of the uniform and regular contexture of its particles , which are ranged as it were in distinct ranks and files , with pores or intervals orderly and directly remaining betwixt them ; hath its pores not so soon determined by particles oppositely disposed , but continued to a greater depth in its substance . though this make the whole matter sufficiently intelligible , yet may it receive a degree more of illustration , if we admit the same conditions to be in the substance of glass , that are in a mist , or cloud ; through which we may behold and object , so long as the small passages or intervals betwixt the particles of the vapours , through which the rayes of the visible species may be trajected , remain unobstructed : but yet perceive the same so much the more obscurely , by how much the more remote it is ; because , in that case , more impervious particles are variously opposed to those small thorow-fares , that obstruct them , and so impede the progress of most of the rayes . for , thus also glass , if thin , doth hinder the sight of an object very little , or nothing at all ; but if very thick , it wholly terminates the progress of the species : and , by how much the thicker it is , by so much the more it obscures the object . and this , only because glass , consisting of small solid particles , or granules , and insensible pores alternately situate , hath many of its pores running on in direct lines through its substance to some certain distance ; but sometimes these ; sometimes those are obturated by small solid particles succedent , when at such a determinate crassitude , it becomes wholly opace . and this gives us an opportunity to refute that vulgar error , that the substance of glass is totally diaphanous , or that all and every ray of the the visive species is trajected through it , without impediment . to demonstrate the contrary , therefore , we advise you to hold a piece of the finest and thinnest venice glass against the sun , with two sheets of white paper , one betwixt the sun and the glass , the other betwixt the glass and your eye : for , then shall all the trajected rayes be received on the paper on this side of the glass , and the reflected ones be received on that beyond it . now , insomuch as that paper , which is betwixt your eye and the glass , doth receive the trajected rayes , with a certain apparence of many small shadows intercepted among them ; and that paper beyond the glass , doth receive the reflected rayes with an apparence of many small lights : therefore we demand ( ) from whence can that species of small shadows arise , if not from the defect of those rayes , that are not transmitted through the glass , but averted from it ? ( ) whence comes it , that in neither paper the brightness or splendour is so great , as when no glass is interposed betwixt them ; if not from hence , that the reflected rayes are wanting to the nearest , the trajected ones to the farthest ? ( ) whence comes it that some rayes are reflected , others trajected ; if not from hence , that as a lawn sieve transmits those rayes , which fall into its pores , and repercusseth others that fall upon its threads : so doth glass permit those rayes to pass through , that fall into its pores ; and reverberate those , that strike upon its solid particles ? and what we here say of glass , holds true also ( in proportion ) of aer , water , horn , vernish , muscovy-glass , and all other diaphanous bodies . chap. x. of magnitude , figure : and their consequents , subtility , hebetude , smoothnesse , asperity . sect . i. the magnitude and figure of concretions , in regard our reason doth best derive them from the two first proprieties , or essential attributes of the universal matter , atoms ; are the qualities which justly challenge our next meditation . concerning their origination , therefore , we advertise first , that although it be not necessary , that a body made up of greater atoms should therefore be greater , nor contrariwise , that a body composed of lesser atoms , should therefore be lesser ; nor that a body consisting of atoms of this , or that determinate figure , should constantly retain that figure , without capacity of determination to any other : yet doth it seem universally true , that every concretion therefore hath magnitude , because its material principles , or component particles have their certain magnitudes , or are essentially endowed with real dimensions ; and as true , that every concretion is therefore determined to this or that particular figure , because the component particles thereof are not immense , or devoyd of circumscription , but terminated by some figure or other . secondly , that the term magnitude here used , is not to be accepted in a comparative intention , or as it stands in opposition to parvity ; in which sense vulgar ears alwayes admit it : but a positive , or as it is identical and importing the same thing with quantity , or extension . for , as every atom , or that ultimate and indivisible portion of matter , so called , is no mathematical point , but possesseth its own simple magnitude , or quantity , without respect or comparison to greater or less . so must every concretion be considered , as it stands possessed of its own compound magnitude , or quantity , without respect to any other body , in comparison whereof it may be said to be greater or less . because without the relative conception of any other body , the mind doth most clearly and dictinctly apprehend the magnitude of a concretion by a positive ●otion ; insomuch it conceives it to have various parts , whereof none are included within other , but all situate in order , and each in its proper place : so that from thence must follow the diffusion of them , and consequently the extension of the whole consisting of them . and well known it is , that the magnitude , or quantity of a body , is nothing but that kind of extension , which amounts from the aggregate of the singular extensions of its component particles : of which if any be conceived to be detracted , or apposed ; so much is instantly understood to be detracted from , or apposed to the extension of the whole body . to this alludes that distich of lucretius , propterea , quia quae decedunt corpora quoique , ●nde abeunt , minuunt ; quo venere , augmine donant . this du●ly perpended , no man need hereafter fear the drilling of his ears by those clamorous and confused litigations in the schools , about the formal reason of quantity ; for nothing can be more evident than this , that 〈◊〉 extension or quantity of a thing is meerly modu● materiae , or ●ather ) the matter it self composing that thing ; insomuch as it cons●●●eth not in a point , but hath parts posited without parts , in respect ●hereof it is diffuse : and purely consequent from thence , that every body hath so much of extension , as it hath of matter , extension ●eing the proper and inseparable affection of matter or substance . hence also may we detect and refute the extreme absurdity of those high-flying wits , who imagine that a body , when rarified , though it hath no more of matter , hath yet more of quantity or extension , than when condensed : because from the praemises it is an apodictical verity , that the extension attributed to a body rarified , 〈◊〉 not an extension of the matter of it alone , but of the matter and small ●nane spaces , intercepted among its dissociated particles , together ; so that if you suppose the extension of those small vacuities to be excluded from the aggregate , you cannot but confess , that the matter hath no more of extension in its parts dissociated , than it had in the same parts coa●unated . moreover , this sufficiently instructs us to give a decisive response to that so long debated quaestion , an per rarifactionem acquiratur , per condensationem deperdatur quantitas ? whether the quantity of a body is augmented in rarifaction , and diminished in condensation , or no ? for , as nothing of matter is conceived to be added to a body , while it is rarified ; nothing of matter detracted from it while condensed : so is it undeniable , at least unrefutable , that nothing of quantity is acquired by rarifaction , or amitted by condensation ; but only that those empty spaces are admitted , or excluded , which being in a rarified body conjoined to the small spaces , that the particles of its matter possess , make it appear to be greater , or to replenish a greater place , than before ; and in a condensed body , detracted from the small spaces , that the particles of its matter do possess , make it appear less , or to fill a less place than before . if so , it may be cause of wonder even to the wisest and most charitable consideration , that the defendants of aristotles doctrine of quantity , have with so much labour and anxiety of mind betrayed themselves into sundry not only inextricable difficulties , but open repugnances ; while on the one side they affirm , that as well quantity as matter , is ingenerable and incorruptible : and on the other admit , that the same matter may be one while extended to the occupation of all and every part of a greater space ; and another while again so contracted , as to be wholly comprehended in the hundreth part of the former space ( as in the condensation of aer into water ) than which no contradiction can be or more open , or more irreconcileable . and yet we see those , who have easily swallowed it , and upon digestion become so transcendently exalted to sublimities , as to imagine the quantity of a thing to be absolutely distinct from the matter , or substance of it : and thereupon to conclude , that rarity and density doe consist only in the several proportions , which substance hath to quantity . much more plausible were their explication , had they derived the extension of a thing , meerly from space , or place ; because , whenever any thing is said to be extense , the mind instantly layes hold of some determinate part of space , referring the extension of it simply and entirely to the place , wherein it is , or may be contained , and which is exaequate to its dimensions : nor is it , indeed , easie to wean the understanding from this habitual manner of conception . whereof if we be urged to render a satisfactory reason , we confess , we know no better than this ; that by the law of nature , every body in the universe is consigned to its peculiar place , i. e. such a canton of space , as is exactly respondent to its dimensions : so that whether a body quiesce , or be moved , we alwayes understand the place wherein it is extense , to be one and the same , i. e. equal to its dimensions . we say , by the lay of nature ; because , if we convert to the omnipotence of its author , and consider that the creator did not circumscribe his own energy by those fundamental constitutions , which his wisedom imposed upon the creature : we must wind up the nerves of our mind to a higher key of conception , and let our reason learn of our faith to admit the possibility of a body existent without extension , and the extension of a body consistent without the body it self ; as in the sacred mystery of our saviours apparition to his apostles , after his resurrection [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] the dores being shut . not that we can comprehend the manner of either , i. e. the existence of a body without extension , and of extension without a body ; for our narrow intellectuals , which cannot take the altitude of the smallest effect in nature , must be confest an incompetent measure of supernaturals : but that , whoever allowes the power of god to have formed a body out of no praeexistent matter ▪ cannot deny the same power to extend to the reduction of the same body to nothing of matter again . which the most pious s. august . ( epist. . ) and yet this hinders not , but a body , which is not actually divided into parts , may be said to be continued ; insomuch as it so appears to the sense , which cannot discern the several commissures of its particles . again , forasmuch as aristotle defines a continuum to be that , whose parts are conjoyned by some common mean , or term ; it is requisite we observe how far forth his definition is consistent with right reason . we allow it to be true physically so far forth , as there are no two parts assignable , which are conjoyned by some third intermediate part , either sensible ( as in a magnitude of three feet , the two extreme feet are copulated together by the third intermediate ) or insensible ( as in the magnitude of two feet , which are joyned together by some interjacent particle , so small as to evade the detection of sense ) : but , if with him we accept that common mean , or terme , for a mathematical point , or individual ( for he expresly affirms , that the parts of a line are copulated by a point ; the parts of a superfice , by a line ; the parts of a body , by a line , or superfice ) t is plain , that our conceptions must be inconsistent with physical verity ; because such insectiles , or individuals are not real , but only imaginary , as we have copiously asserted in our discourse concerning the impossible division of a continuum into parts infinitely subdivisible . besides , who can conceive that to be a caement or glew to unite two parts into one continued substance , which hath it self no parts designable either by sense or reason ? nor can any thing be rightly admitted to conjoyn two bodies , unless it hath two sides , extremes , or faces ; one whereof may adhaere to one of the two bodies , the other to the other , so as to make a sensible continuity . concerning the quality of a body called figure , that which is chiefly worthy our praesent adversion , is onely this ; that if figure be considered physically , it is nothing but the superficies , or terminant extreames of a body . we say , physically ; because geometricians distinguish figures into superficial , or plane , and profound , or solid : but the physiologist knows no other figure properly , but the superficial ; because , in strict truth , the profound or solid one seems to him , to be rather the magnitude , or corpulency of a thing circumscribed or terminated by its figure , than the figure it self abstractedly intended . nay , if we insist upon the rigour of verity , the figure of a body is really nothing but the body it self ; at least , the meer manner of its extreme parts , according to which our sense deprehends it to be smooth or rough , elated or depressed . this may be most fully evinced by only one example , viz. the figure made upon wax by the impression of a seal . for , that figure really is nothing but the very substance of the wax , in some parts made more eminent , in others more deprest , or profound , according to the reverse of its type ingraven in some hard substance ; and that without adjection , or detraction o● any entity whatever . and what we affirm of the figure made in wax by sigillation , is of equal truth ( proportionately ) if accommodated to any other figure whatever : no● doth it imply a difference , whether the figure be natural , such as in animals , vegetables , minerals ; or artificial , such as in aedifices , statues , characters , &c. sect . ii. the 〈◊〉 of magnitude and figure in concretions ▪ being thus 〈…〉 follows , that we explore their effects , i. e. the qualities which seem so immediately cohaerent to the magnitude and figure of bodies as that reason cannot consigne them to more likely and probable principles , than the two first proprieties of the universal matter , atoms ▪ the 〈◊〉 , therefore , of magnitude , are subtility and its 〈…〉 . not that the emergency of a great body from atoms the 〈◊〉 exile ; or of a small body from great atoms , is impossibl● ▪ 〈…〉 formerly intimated : but , that a body consisting of more exil● ▪ 〈…〉 a●om● , hath a greater subtility , or obtains a faculty of pen●●●ating the contexture of another body , by subingression into the pores , 〈…〉 ●hereo● ▪ and a body consisting of grosser atoms , must have more of 〈…〉 hebe●ude , and so hath not the like faculty of penetrating the co●●●xtures of other bodies , by subingression into the mane spaces ▪ o● inte●●●●● betwixt their particles . this may be exemplified in fire and 〈…〉 and oyle ; aqua fortis and milk , &c. we are 〈◊〉 now to learn the truth of that chymical canon , cuique 〈…〉 , vel extrahendae eligendum esse idoneum menstruum , quod 〈…〉 respondeat : experience having frequently ascertained us , that aqu● 〈◊〉 , which soon dissolves the most compact of bodies , gold , will no● 〈…〉 re●ine . pitch , wax ▪ and many other unctuous and re●inous 〈◊〉 ; which yeild almost at first touch to the separatory ●acu●ty 〈…〉 that mercurial waters expeditely insinuate into the substance of gold , dissolve the continuity of its stiffly cohaerent particles and 〈◊〉 from a most solid into an oyly substance ; not so much by 〈…〉 ●ymbolisme or affinity of nature : that salt , nitre , and sulphur , whic●●eing added to sand , flints , and many metals , promote the solution , 〈…〉 fire ; have yet no accelerating , but a retarding energy upo● turpentine , balsome , myrrh , &c. in the extraction of their oyls , or 〈◊〉 that all waters , or spirits extracted from sa●ine and metalline nature are most convenient menstruaes for the solution of metals & minerals ; not 〈◊〉 much in respect of their corrosion , as similitude of pores and particles and consequently that every concretion requires to its dissolution some 〈◊〉 dissolvent , that holds some respondency or analogy to its contexture . 〈◊〉 yet have we no reason , therefore to abandon our assumption ▪ that 〈◊〉 dissolution of one body , by the subingression or insinuation 〈…〉 another , must arise from the greater subtility of particles 〈…〉 , until it be commonstrated to us , that a body , whose 〈…〉 can penetrate another body , whose pores are more 〈…〉 whereto is demonstrated to us by the frequent experiment● of 〈◊〉 . and , therefore , the reason , why oyle olive doth pervade some bodies , which yet are impenetrable even by spirit of wine ( by ●aimundus lullius , and after him by libavius and quercetan , accounted the true sulphur and mercury of hermetical philosophers , extracted from a vegetable , for the solution of gold into a potable substance , and the confection of the great elixir ; and as general a dissolvent , as that admired ( but hardly understood ) liquor alkahest of paracelsus , if not the same ) can be no other but this : that in the substance of oyle are some particles much more subtile and penetrative , than any contained in the substance of wine ; though those subtile particles are thinly interspersed among a far greater number of hamous , or hooked particles , which retard their penetration . thus also in that affrighting and atheist-converting meteor , lightning , seem to be contained many particles much more exile and searching than those of our culinary fires : because it sometimes dissolves the hardest of metals in a moment , which preserve● its integrity for some hours in our fiercest reverberatory furnaces . which lucretius well expresseth in this tetrastich ; dicere enim possis , caelestem fulminis ignem subtilem magis , e parvis constare figuris ▪ atque ideo transire foramina , quae nequit ignis noster hic elignis ortus taedaque creatus . secondly , the qualities consequent to figure , are smoothnesse , and its contrary , asperity . not that , if we appeal to the judgement of the sense , the superfice of a body may not be smooth , though it consist of angulou● atoms ; or rough , though composed of plain and polite atoms : for , all atoms , as well as their figures , are so exile , as that many of them that are angular , may cohaere into a mass , without any inequality in the superfice deprehensible by the sense ; and on the contrary , many of those that are plane and polite , may be convened and concreted into such masses , as to make angles , edges , and other inequalities sufficiently sensible . but , that if we refer the matter partly to the judicature of reason , partly to the evidence of our senses in general ; we cannot but determine it to arise from the figuration of atoms alone . first , to the judicature of reason ▪ for , as the mind admits nothing to be perfectly continued , besides an atom : so can it admit nothing to be exquisitely smooth , besides either the whole superfice of an atom , ●f the same be orbicular , oval , or of the like figure ; or som parts of it , if the same be tetrahedical , hexahedrical , or of some such poligone figure . because , look by what reason the mind doth conclude the superfice of no concretion in nature to be perfectly continued : by the same reason doth 〈◊〉 ●●nclude the superfice of every thing , seemingly most equal and polite , to be ●●r●●usly interrupted with asperities , or eminent , and deprest particles ; and 〈…〉 refers immediately and sole●y to many small masses of atoms , in 〈◊〉 contexture coadunated , like as it referrs the interruptions in the superfice of a piece of lawne , or cambrique , which to the eye and touch appears most smooth and united , to the small masses of filaments interwoven in the webb . and here the experiment of a microscope is opportune ; for , when a man looks through it upon a ●heet of the finest and ●moo●hest venice paper , which seems to the naked eye , and most exquisite touch , to be equal and ●erse in all parts of it superfice ▪ he shall discern it to be so full of eminences and cavities , or small hills and valleys , as the most praegnant and praepared imagination cannot suppose any thing more unequal and impolite . se●ondly , to the evidence of our senses in general ; because , the very af●●ction of pleasure or pain , arising to the sensory from the contact of the s●●●ible object , doth sufficiently demonstrate , that smoothness is a quality 〈◊〉 either from such atoms , or such small masses of atoms contexed , as 〈◊〉 smooth and pleasant to the sense , by reason of their correspondence 〈◊〉 ●he pores and particles of the organ : and contrariwise , that ●sperity is a ●uality , resulting either from such single atoms ▪ or such most minute masses of atoms concreted , as dilacerate , or exasperate the sense , by reason of 〈◊〉 incongruity or disproportion to the contexture of the organ : as w● 〈◊〉 , even to redundancy , exemplified in the grateful and ungrateful 〈◊〉 of each sense . chap. xi . of the motive vertue , habit , gravity , and levity of concretions . sect . i. the third propriety of the universal matter , atoms , is mobility , or gravity : and from that fountain is it that all concretions derive their virtue motive . for , though our deceptable sense inform us , that the minute particles of bodies are fixt in the act of their coadunation , wedged up together , and as it were fast bound to the peace by reciprocal concatenation and revinction : yet , from the d●ssolution of all compound natures , in process o● time , caused by the intestine commotions of their elementary principles , without the hostility of any external contraries , may our more judicious reason well inferr , that atoms are never totally deprived of that their essential faculty , mobility ; but are ance●santly agitated thereby even in the centrals of concretions , the most so●id and compact ; some tending one way , others another , in a perpetual 〈◊〉 of eruption , and when the major part of them chance to ●ffect 〈…〉 the same way of emancipation , then is their united force determimined ●o one part of the concretion , and motion likewise determined to one region , respecting that part. that same motive virtue , there●ore , wherewith every compound bodie is naturally endowed , must owe ●ts ●rigine to the innate and co-essential mobility o● its component particles ▪ being really the same thing with their gravity , or impetus : which yet receives its determinate manner and degree from their mutual combination . in respect whereof it necessarily comes to pa●s , that when atoms , mutually adh●ering vnto 〈…〉 other , ca●●ot obey the ●mpu●●e of 〈◊〉 ●●ndency singly , they are not moved with that pernicity , as if each were a●●●solute liberty ; but impeding and retarding each other in their progress , ar●●●rried with a flower motion , but that more or less slow , according to 〈◊〉 rate or proportion of common resistence : because always some of them are carryed to an opposite , others transversly , others obliquely to a dif●●rent region . an● 〈◊〉 is it , that because atoms are at most freedom of range in 〈…〉 concretions ▪ every degree of density and compactness causin● 〈◊〉 ●●oportionate degree of tardity in their spontaneous motions : 〈…〉 the motive faculty not more generally , than rightly conceived , 〈…〉 chiefly in the spiritual , or ( as vulgar philosophy ) aethereal parts 〈◊〉 concretions . and , whether the spirits of a thing are principa● de●●●mined to move , thither do they not only themselves contend , 〈…〉 and speed , but also carry along with them the more 〈…〉 less mov●able parts o● the concretion ; as is superlatively 〈…〉 voluntary motions o● animals . w● 〈◊〉 not here insist upon the redargution of that blasphemous and absur● 〈◊〉 the forme● epi●hit● always implies the later ) dream of 〈…〉 atoms wer● not only the first matter , but also the first and 〈…〉 of all things ▪ and consequently that all motions , and so all 〈…〉 ●niverse and caused meerly by the inhaerent mobility of them : be 〈…〉 have expresly refuted the same in our treatise against atheism , 〈…〉 . artic . ultim ) . especially , since it is more opportune for us her● 〈…〉 ; that insomuch as the motion of all atoms is supposed 〈…〉 d●rect , and most rapid ; therefore doth the deviation , as 〈…〉 of concretions seem to arise from the deflection , repercussion 〈…〉 repression of the atoms composing them . for , the 〈…〉 meeting of two atoms ▪ may be in direct lines : so that among 〈…〉 singl● percussion ▪ or repercussion overcom●ng the first begun 〈…〉 assembly o● conventi●n will bear , there may be caused some 〈…〉 ●hough more or less slow : and their occursations may be 〈…〉 oblique angles , and so , by the same reason may ensue a 〈…〉 more or less slow , but also more or less oblique . more●ve● 〈…〉 repe●cussion made to oblique angles , there chance to 〈…〉 repercussion to angles equally oblique ; then must the 〈…〉 ●bl●quity multangular , according to the multiplicity 〈…〉 the angles be very frequent and indistant ▪ the 〈…〉 at least to appearance , to be of an uniform curvity , and 〈…〉 be termed a motion circular , elliptical , helico●●al , 〈…〉 a●cording to the condition of its deflection and crooked●●●● . 〈…〉 observ● , tha● every body , whether simple or 〈…〉 concretion , fr●m which a repercussion is made , must 〈…〉 b● move● the same way , as is the repercust , or not 〈…〉 because , otherwise there can be no mutual 〈…〉 impingent body rebound from the repercuti●● 〈…〉 , why ●excepting only the motion 〈…〉 of all concretions doth ever suppose something that remains unmoved , or that , in respect of its less motion , is tantamount to a thing unmoved : because , otherwise there could be no reciprocal resistence , and so all motion might both begin and repair it self . having thus premised these few fundamental laws of motion in general , opportunity commands us to descend to the consideration of the faculty of motion : insomuch as it seems not to be any thing distinct from that motive force , inhaerent in all concretions , which we have now both described , and deduced from its immediate origine , the mobility of atoms ; and that it is well known to all book-men , to appertain to the second species of qualities , according to the method of aristotle . to which we may add these lessons also , that it comprehends the third species of qualities , and obtains the first , or habit , as its proper appendix . know we , therefore , that the faculty or power of motion doth therefore seem to be one and the same thing with the coessential mobility , now described ; because every thing in nature is judged to have just so much of efficacy , or activity , as it hath of capacity to move either it self , or any other thing . and hence is it , that in nature there is no faculty ( properly ) but what is active ; because , though the motions of things be really the same with their actions : yet must all motion have its beginning only from the movent , or agent . nor can it avail to the contrary , that all philosophers have allowed a passive faculty to be inhaerent in all concretions ; since , in the strict dialect of truth , that passiveness is no other than a certain impotency of resistence , or the privation of an active power , in defect whereof the subject is compelled to obey the energy of another . if you suppose an obscure contradiction in this our assertion , and accordingly object ; that therefore there must be a faculty of resistence , in some proportion , and that that resistence is passive : we are provided of a satisfactory salvo , which is , that though the active virtue , which is in the resistent , doth sometimes scarce discover it self , yet is it manifest , that there are very many things , which make resistence only by motion , which no man can deny to be an active faculty ; as when we rowe against wind and tide , or strive with a bowe in the drawing of it , for all these evidently oppose our force by contrary moton . and , as for other things , which seem to quiesce , and yet make some resistence ; such we may conceive to make that resistence by a kinde of motion , which physicians denominate a tonick motion ; like that of the eye of an animal , when by the contraction of all its muscles at once it is held in one fixt position . thus not only the whole globe of the earth , but all its parts are held unmoved , and first by mutual cohaerence , and resist motions as they are parts of the whole : and thus also may all concretions be conceived to be made immote , not that the principles of which they consist ▪ are not in perpetual inquietude and motion ; but , because their par●●cles reciprocally wedge and implicate each other , and while some impede ●nd ●ppose the motions of others , they all conspire to the consistence of ●he whole . however the more learned and judicious shall further dispute ●his paradoxical argument ; yet dare we determine the common noti●n of a faculty to be this , that there is inherent in every thing a prin●●ple of moving itself , or acting , if not primary●which ●which the schools terme the forme ) yet secondary at least , or profluent from the forme , being as it were the immediate instrument thereof . and here we cannot conceal our wonder , that the peripatetick hath not for so many ages together discovered himself to be intangled in a manifest contradiction ; while on one part he affirms , that there are certain faculties flowing â tota substantia , from the whole substance of a thing , as if they were derived from the matter of concretions : and on the other , concludes , as indisputable , that the matter is absolutely devoid of all activity , as if it were not certain , that the faculties frequently perish , when yet not the whole and intire substance of the thing perisheth , but only the spiritual , or more tenuious parts thereof . now , what more praegnant argument than this can the most circumspect desire , in order to their conviction , that the faculties of an animal ( we exclude the rational faculty of man , from the sphere of our assertion ) ar● identical with the spirits of it , i. e. the most subtile , most free , and most moveable or active part of its materials ? for , though the spirits are by vulgar philosophers conceived to be only the primary organ , or immediate instrument , which the faculty residing in one part , occasionally transmits into another : yet , to those worthies , who have with impartial and profound scrutiny searched into the mystery , hath it appeared more consentaneous , that the spirits are of the same nature with the faculty , and not only movent , but instrument ; nor can it stand with right reason to admit more than this , that as water in the streams is all one specifically with that in the fountain , so is the faculty , keeping its court or chief residence in one part of the body , as it were the fountain , or original , from whence to all other parts , inservient to the same function , the diffusion of spirits is made , in certain exile rivolets , or ( what more neerly attains the abstrusity ) rayes , like those emitted from the sun , or other fountain of light . and , what we here say , of the faculties of animals , holds equal truth , also concerning those of inanimate concretions ; allowing a difference of proportion . but here ariseth a considerble difficulty , that at first view seems to threaten our paradox with total ruine ; and this it is : if the faculties of concretions be not distinct in essence from their spirits , or most agile particles ; how then can there be so many various faculties coexistent in one and the same concretion , as are dayly observed ; for in an apple , for example , there is one faculty of affecting the sight , another of affecting the taste , a third affecting the smell . concerning this , therefore , we give you this solution , that the coexistence of various faculties in one concretion , doth depend upon ( ) the variety of multiforme particles , of which the whole concretion doth consist , ( ) the variety of particles and special contexture of its divers parts , ( ) the variety of external faculties , to which it happens that they are applied . to keep to our former example , in an apple , t is manifest , there are some particles , in which consisteth its faculty of affecting the smell , others in which consisteth its faculty of affecting the tast ; for , the experiments of chymistry demonstrate , that these different particles may be so sequestred each from other , as that the tast may be conserved , when the smell is lost , and the smell conserved , when the taste is abolished . and in an animal it is no less evident , that the organ of one sense hath one peculiar kind of contexture , the organ of another sense another : and finally , that when we shall referr the faculties of odour and sapour , which are in an apple , to the faculties of smelling and tasting in animals ; they become subject to a further discrimination . since the same particles , which move the smelling , shall create a sweet and grateful odour , in respect of one animal , and an offensive or stinking , in respect of another : and in like manner , those particles , which affect the taste , shall yeild a most grateful and desireable sapour , to one animal , and as odious and detestable a one to another . ought we , therefore , to account that faculty of an odour , which is in an apple , either single , or multiplex ? if we would speak strictly , it is single absolutely : respectively , multiplex . and thus , indeed , may we affirm , that in the general , or absolutely , an apple is odorous and sapid : but comparatively and in special , that it is fragrant , or foetid ; sweet or bitter . as for that appendix of a faculty , which not only philosophers , but the people also name a habit ; experience daily teacheth , that there are some faculties , ( in animals especially ) which by only frequency of acting grow more prompt and fit to act : and upon consequence , that that hability or promptness for action , is nothing but a facility of doing , or repeating that action , which the same faculty , by the same instruments , hath frequently done before . and , as to the reason of this facility ; though it arise in some measure from the power or faculty it self , or the spirits , as being accustomed to one certain motion : yet doth it chiefly depend upon the disposition of the organs , or instruments which the faculty makes use of in the performance of its proper action . for , because the organ is alwayes a dissimilar or compound body , consisting of some parts that are crass and rigid ; we are to conceive it to be at first somewhat stubborn , and not easily flexible to such various motions , as the faculty requires to its several operations : and therefore , as when we would have a wand to be every way easily flexible , we are gently and frequently to bend it , that so the tenour of its fibres running longwise through it , may be here and there and every where made more lax , without any sensible divulsion ; so if we desire to have our hands expedite for the performance of all those difficult motions that are necessary to the playing of a lesson on the lute , we must by degrees master that rigidity or clumsiness in the nerves , tendons , muscles and joints of our fingers , yea in the very skin and all other parts of our hands . thus also infants , while they stammer , and strive again and again to pronounce a word clearly and distinctly , do no more than by degrees master the stiffness and sluggishness of their tongues and other vocal organs , and so make them more flexible and voluble : and when by assuefaction they have made them easily flexible to all the motions required to the formation of that idiome , then at length come they to speak it plainly and perfectly . the same is also true , concerning the brain , and those organical parts therein , that are inservient to the act of imagination , and by the imagination to the act of discourse . for , though the mind , when divorced from the the body , can operate most readily , and knows no difficulty or impediment in the act of intellection ; as being immaterial , and so wanting no organs for the exercise of its reasoning faculty : yet nevertheless , while it is adliged to the body and its material instruments , doth it remain subject to some impediment in the execution of its functions ; and because that impediment consisteth only in the less aptitude or inconformity of its proper organs , therefore the way to remove that impediment , is only by assuefaction of it to study and ratiocination . and from this assuefaction may the mind be affirmed to acquire a certain habit or promptitude to perform its proper actions ; insomuch as by reason of that habit , it operates more freely and expeditely : but , yet , in stricter logick , that habit ariseth chiefly to its organs ; as may be inferred only from hence , that the organs are capable of increment and decrement , and to increase and decrease , is competent only to a thing that consisteth of parts ; such as is the organ , not the mind . nor is the acquisition of a habit by assuefaction proper only to man , but in common also to all living creatures , such especially as are used to the hand and government of man , as horses , doggs , hawks , and all prating and singing birds . and where we affirmed , that some faculties are capable of advancement to perfection by habit ; we intended , that there are other faculties which are incapable thereof , as chiefly the natural faculties in animals , and such as are not subject to the regiment of the will : though still we acknowledge that some of these there are , which upon change of temperament in their respective organs , may acquire such a certain habit , as may oppose the original inclination ; and of this sort the principal is the nutrient faculty , which may be accustomed even to poison . lastly , when we , said chiefly in animals ; we were unwilling totally to exclude plants ; because they also seem ( at least analogically ) to acquire a kind of habit : as is evident from their constant retaining of any posture or incurvation , which the hand of the gardiner hath imposed upon them , while they were tender and flexible ; as also that they may by degrees be accustomed to forein soils , and ( what is more admirable ) if in their transplantation those parts of them , which at first respected the south or east , be converted to the north or west , they seldome thrive , never attain their due procerity . nay , if the experiments of some physitians be true , minerals also may be admitted to attain a habit by assuefaction ; for baptista van helmont , ( in lib. de magnetica vulnerum curatione , & lib. de pestis tumulo ) reports that he hath found a saphire become so much the more efficacious an attractive of the pestilential venome from the vitals , by how much the more frequently it hath been circumduced about carbuncles or plague sores ; as if custome multiplied its amuletary virtue and taught it a more speedy way of conquest . sect . ii. among all qualities of concretions , that deduce themselves from the mobility of atoms , the most eminent is gravity , or the motion of perpendicular descent from weight . which , though most obvious to the observation of sense , hath much of obscurity in its nature ; leading the reason of man into various and perplext conceptions concerning its causes : nor hath the judgment of any been yet so fortunate as to light upon a demonstrative theory concerning it , or fix upon such a determination as doth not lye open to the objection of some considerable difficulty . so that it may well seem ambition great enough for us , onely with due uprightness to examine the verisimility of each opinion , touching the formal reason , or essence of gravity : that so we may direct younger curiosities , in which they may , for the praesent , most safely acquiesce . epicurus , indeed , well desumes the gravity of all concretions , immediately from the gravity of simple bodies , or atoms : insomuch as all things are found to have so much more of weight , as they have of atoms , or matter , that composeth them ; and è contra . which reason the exact ioh. bapt. balianus , a nobleman and senatour of genoa , seriously perpending ; sets it down as a firm ground , gravitatem se habere ut agens , materiam vero , seu materiale corpus , ut passum ; & proinde gravia moveri juxta proportionem gravitatis ad materiam : & ubi sine impedimento naturalitèr perpendiculari motu ferantur , moveri aequalitèr ; quia ubi plus est gravitatis , plus ibi paritèr sit materiae , seu materialis quantitatis ; ( de motu gravium solidorum & liquidorum , lib. . cap. . ) . but , this being too general , and concerning rather the cause of comparative , than absolute gravity ; leaves our curiosity to a stricter search . the grand dictator of the schools , aristotle , taking it for granted [ unumquodque sensilium ita in suum locum ferri , ut ad speciem ] that every corporeal nature is by native tendency carried to its proper place , as to its particular species ; confidently inferrs this doctrine : that gravity and levity are qualities essentially inexistent in concretions ( . de caelo , cap. . ) and passionately reprehending democritus and leucippus , for affirming that there is no such thing in nature , as absolute gravity , or absolute levity ; concludes , that in nature is something absolutely heavy , which is earth , and something absolutely light , which is fire ; ( de caelo , lib. . cap. . ) but , neither of these positions are more than petitionary ; and so not worthy our assent : as the context of our subsequent discourse doth sufficiently convince . the third opinion worthy our memory , is that of copernicus , who considering , that all heavy bodies , either projected upwards by external violence , or dropt down from some eminent place , are observed to fall perpendicularly down upon the same part of the earth , from which they were elevated , or at which they are aimed , and so that the earth might be thence argued not to have any such diurnal vertigo , as his systeme ascribes unto it , insomuch as then it could not but withdraw it self from bodies falling down in direct lines , and receive them at their fall not in the same place , but some other more westernly : we say , considering this , copernicus determined gravity to be , not any internal principle of tendency toward the middle , or centre of the universe ; but an innate propension in the parts of the earth , separated from it , to reduce themselves in direct lines , or the nearest way , to their whole , that so they may be conserved together with it , and dispose themselves into the most convenient , i. e. a sphaerical figure , about the centre thereof . his words are these ; equidem existimo , gravitatem non aliud esse , quàm appetentiam quandam naturalem , partibus inditam à divina providentia opificis universorum ; ut in unitatem integritatemque suam sese conferant , in formam ●lobi coeuntes : quam affectionem credibile est etiam soli & lunae , caeterisque errantibus fulgoribus inesse ; ut ejus efficacia in ea , qu● se repraesentant , rotunditate permaneant . ( lib. . cap. . ) . so that according to this copernican assumption , if any part of the sun , moon , or other coelestial orb were divelled from them ; it would , by the impulse of this natural tendency , soon return again in direct lines to its proper orb , not to the centre of the universe . which as kepler ( in epitom . astronom . pag. ● . ) well advertiseth , is but a point , i. e. nothing , and destitute of all appertibility ; and therefore ought not to be accounted the term of tendency to all heavy bodies , but rather the terrestrial globe together with its proper centre , yet not as a centre , but as the middle of its whole , to which its parts are carried by cognation . but , this opinion hath as weak a claim to our assent , as either , of the former ; as well because it cannot consist with the encrease of velocity in all bodies descending perpendicularly , by how much nearer they approach the earth , unless it can be demonstrated , that this encrease of velocity in each degree of descent , ariseth only from the encrease of appetency of union with the whole ( which neither copernicus himself , nor any other for him , hath yet dared to assent ) : as in consideration of many other defects , and some absurdities , which , that wonder of the mathematicks , ricciolus , hath demonstratively convicted it of ( in almegisti novi parte posteriori , lib. . sect . . cap. . de systemate terrae motae . ) . who , had he but as solidly determined all the difficulties concerning the immediate cause of this affection in bodies , called gravity ; as he hath refuted the copernican thesis of an innate appetency in the parts of the earth to reunite themselves to the whole : doubtless he had much encreased the obligations and gratitude of his readers . but , making it his principal design to propugn the physiology and astronomy of the ancients , especially such tenents as are admitted by the schools , and allowed of by the doctors of rome , as most concordant to the litteral sense of sacred writ : he waved that province , seeming to adhaere to the common doctrine of the stagirite , formerly recited , and only occasionally to defend it . lastly , there are others ( among whom kepler and gassendus deserve the richest minervals ) who , neither admitting with aristotle , that gravity is any quality essentially inhaerent in concretions ; nor , with copernicus , that it is an appetency of union , implanted originally in the parts of the earth , by vertue whereof they carry themselves towards the middle of the terrestrial globe : define it to be an imprest motion , caused immediately by a certain magnetick attraction of the earth . and this opinion seems to carry the greatest weight of reason ; as may soon be manifest to any competent and equitable judgment , that shall exactly perpend the solid arguments alledged by its assertors : which for greater decorum , we shall now twist together into one continued thread , that so our reader may wind them into one bottome , and then put them together into the ballance . insomuch as frequent and most accurate observation demonstrates , that the motion of a body downward doth encrease in the same proportion of velocity , that the motion of the same body , violently projected upward , doth decrease ; therefore is it reasonable , nay necessary for us to conceive , that there are two distinct external principles , which mutually contend about the same subject , and execute their contrary forces upon the same moveable . now , of these two antagonistical forces , the one is evident ; the other obscure , and the argument of our instant disquisition . manifest it is , when a stone is thrown upward from the surface of the earth into the aer , that the external principle of its motion upward , is the hand of him , who projected it : but somewhat obscure , what is the external principle of its motion downward , when it again returns to the earth . nevertheless , this obscurity doth not imply a nullity , i. e. it is high temerity to conclude that there is no external cause of the stones descent , because that external cause is not equally manifest with that of its ascent : unless any dare to affirm , that because he can perceive , when iron is attracted to a loadstone , no externall cause of that attraction , therefore there can be none at all . many , indeed , are the wayes , by which an external cause may move a body : and yet they all fall under the comprehension of only two cardinal wayes , and those are impulsion , and attraction . this praeconsidered , it followes , that we cast about to finde some cause , or impellent , or attrahent ( or rather two causes , one impellent , the other attrahent , operating together ) to which we may impute the perpendicular motion of bodies descending . the impellent cause ( if any such there be ) of the perpendicular motion of a stone descending , can be no other but the aer , from above incumbent upon , and pressing it downward : because of any other external cause of that effect , no argument can be given . for , should you suppose a sphere of fire , or some other or some other aethereal substance , to be immediately above the convex ext●eme of the sphere of aer ; which closely and with some kind of pressure invironing the aer , might compel all its parts to flow together toward the terraqueous globe : yet could that super-aereal sphere , bounded and urged by the circumvolutions of the coelestial orbs , do no more , than cause the aer , being it self prest downward , to bear down upon the stone , and so depress it ; and so the aer must still be at least the proxime cause impelling the stone downward . moreover , that the aer alone may be the impellent cause of the stones perpendicular decidence from on high , even aristotle himself seems to concede ▪ insomuch as he is positive in his judgment , that when a heavy body projected upward is abandoned by its motor , it is afterward moved only by the aer , whi●h being moved by the projicient , moves the next conterm●●ous aer , by which again the next neighbouring aer is like●●se moved , an● so successively forward untill the force of the imprest motion gradually decaying , the whole communicated motion ceaseth , and a quiet succeeds . but , betause aristo le could not tell , what cause that is ▪ which in every degree of the stones ascent opposing , at length who●●● overcomes the imprest force ; un●ess it should be the occurrent superiour aer , which continually resisteth the inferior aer , whereby the projected stone is promoted in its ascent : may not we safely enough conclude , that the aer from above incumbent upon the projected stone , may by the same force depress it downward , wherewith it first resisted the motion of it upward ? doubtless , what force● soever the hand of a man , who projects a stone upward into the aer , doth impress upon it , and the contiguous aer ; yet still is 〈◊〉 the superiour aer , that both continually resisteth the tendency 〈◊〉 the stone upward , and at its several degrees of ascent re●racteth 〈◊〉 force thereupon imprest by the hand of the projicient , unt●●● having totally overmastered the same , it so encreaseth its conqu●●●g depellent force , as that in the last degree of the stones de●endent motion , the depressive force of the aer is become as great , as was the elevating force of the hand , in the beginning of 〈◊〉 ascendent motion . suppose we , that a diver should from the bottome of the sea throw a stone directly upward , with the same ●●●ce , as from the surface of the earth up into the aer ; and then ●●mand , why the stone doth not ascend to the same height in the water , as in the aer . is it not , think you , because the 〈◊〉 doth more resist , and refract the imprest force , and so soo●●● overcome it , and then begins to impress its own con-contrary depressing force thereupon , never discontinuing that impression , 〈◊〉 it hath reduced the stone to the bottom of the sea , from whe●●● it was projected ? the difference , therefore , betwixt the resistence of the imprest force , by the water , and that of the aer ●●●sisteth only in degrees , or more and less . and , though the 〈◊〉 of the aer may be thought very inconsiderable in comparison o● 〈◊〉 great violence imprest upon a cannon bullet , shot upw●rd 〈…〉 the aer : yet be pleased to consider , that it holds some 〈◊〉 proportion , with the renitency o● the water . which 〈…〉 that we may understand , compare we not only the very 〈◊〉 ascent of a stone , thrown upward from the bottome of the sea , to the large ascent of the same stone , with equal force , from the earth , thrown up into the aer ; but also the almost insensible progress of a bullet shot from a cannon transversly through water , with that vast progress it is commonly observed to make through the aer : and we shall soon be convinced , that as the great resistence of the water is the cause , why the stone , or bullet makes so small a progress therein ; so is the small resistence of the aer the cause why they both pervade so great a space therein . and thus is it demonstrable , that the resistence of the superior aer , is the external agent , which constantly resisteth , by degrees refracteth , and at length wholly overcomes the imprest force , whereby heavy bodies are violently elevated up into the aer . the difficulty remaining , therefore , doth only concern the impellent cause of their fall down again ; or , whether the aer , besides the force of resistence , hath also any depulsive faculty , which being imprest upon a stone , bullet , or other ponderous body , at the top , or highest point of its mountee , serveth to turn the same downward , and afterward to continue its perpendicular descent , till it arrive at and quiesce on the earth . which , indeed , seems well worthy our doubt , because it is observable , that walls , pavements , and the like solid and immote bodies , though they strongly resist the motion of bodies impinged against them ; doe not yet impress any contrary motion thereupon : the rebound of a ball or bullet from a wall , being the effect meerly of the same force imprest upon it by the racket , or gun-powder fired , which first moved it ; as is evident even from hence , that the resilition of them to greater or less distance , is according to the more or less of the force imprest upon them . which those gunners well understand , who experiment the strength of their powder , by the greatness of the bullets rebound from a wall. and to solve this difficulty , we must distinguish betwixt bodies , that are devoid of motion , and which being distracted , have no faculty of restitution , whereby to recollect their dissociated particles , and so repair themselves ; of which sort are walls , pavements , &c : and such bodies that are actually in motion , and which by reason of a natural elater , or spring of restitution , easily and speedily redintegrate themselves , and restore their severed parts to the same contexture and tenour , which they held before their violent distraction ; to which classis the aer doth principally belong . now , concerning the first sort , what we object of the non-impression of any contrary motion upon bodies impinged against them , is most certainly true : but not concerning the latter . for , the arm of a tree , being inflected , doth not only resist the inflecting force , but with such a spring return to its natural site , as serveth to impel any body of competent weight , that shall oppose its recurse , to great distance ; as in the discharge of an arrow from a bow. thus also the aer , though otherwise unmoved , may be so distracted by a body violently pervading it ; as that the parts thereof , urged by their own native confluxibility ( the cause of all elaterical or restorative motion ) must soon return to their natural tenour and site , and not without a certain violence , and so replenish the place form●rly possest , but now deserted by the body , that distracted them . th●● there is so powerful a restorasive faculty in the aer , as we here ●ssume ; innumerable are the experiments , those especially by philosophers usually alledged against a vacuum coacervate , which attest . however , that you may the less doubt of its having some , and a consid●rable force of propelling bodies notwithstanding it be fluid in so high a degree : be pleased only to reflect your thoughts upon the great ●orce of winds ; which tear up the deepest and firmest rooted cedars ●●om the ground , demolish mighty castles , overset the proudest c●●racts , and rowle the whole ocean up and down from shoar to sho●● . consider the incredible violence , wherewith a bullet is discharged from a wind-gun , through a firm plank of two or three inches thickness . consider that no effect is more admirable , than that a very small quantity of flame should , with such prodigious impetuosity ▪ drive a bullet , so dense and ponderous , from a cannon , through th● gates of a city , and at very great distance : and yet the flame 〈◊〉 the gunpowder is not less , but more fluid than aer . who , without the certificate of experience , could believe , that meerly by the force of so little flame ( a substance the most fluid of 〈◊〉 , that we know ) not onely so weighty a bullet should be driven with such pernicity forward through the aer to the distance of many furlongs ; but also that so vast a weight , as a cannon and its carriage bear , should at the same time be thereby driven backwards , or made to recoyle ? what therefore will you say , if this could not come to pass , without the concurrence of the aer ? for ▪ it seems to be effected , when the flame , at the instant of its creation , seeking to possess a more ample room , or space , doth conv●● its impetus , or violence as well upon the breech , or hinder part 〈◊〉 the canon , as upon the bullet lying before it in the bore or 〈◊〉 ; which discharged through the concave , is closely prest upon 〈◊〉 the pursuing flame : so that the flame immediately perishing ▪ 〈◊〉 leaving a void space , the aer from the front or adverse part insta●● rusheth into the bore , and that with such impetuous pernicity , 〈◊〉 it forceth the cannon to give back , and yeilds a fragor , or report ▪ as loud as thunder ; nay , by the commotion of the vicine aer 〈◊〉 ●●akes even the largest structures , and shatters glass-windows 〈◊〉 in the sphere of its violence . and all meerly from the 〈◊〉 motion of the aer , restoring its distracted parts to their n●●ural tenour , or laxity : so that you may be satisfied of its capacity not only to resist the ascent of a stone thrown upward ; but also of depelling it downward , by an imprest motion . notwithstanding our conquest of the main body of this difficulty , abou● the restorative motion of the aer , we are yet to encounter 〈◊〉 formidable reserve , which consists of these scruples . when a 〈◊〉 is thrown upward , doth not the aer in each degree of 〈◊〉 ascent , suffer a distraction of its parts ; and so is compelled 〈◊〉 a periosis , or circular motion , to succeed into the place left below by the stone ? doth it not therefore impress rather an 〈◊〉 , than a depulsive force thereupon , and so promote the force imprest upon it by the hand of him , who projected it ? and must it not thence follow , that the first imprest motion is so far from being decreased by the supposed renitency of the superior aer , that it is rather increased and promoted by the circulation thereof : and upon consequence , that the stone is carried upward twice as swiftly , as it falls downward , since it is impelled upward by two forces , but falls down again only by a single force ? true it is , that while a stone is falling down , the distracted aer beneath seems to circulate into the place above deserted thereby : but , in case a stone be held up on high in the aer by a mans hand , or other support , and that support be withdrawn so gently , as to cause no considerable commotion in the aer ; in this case there seems to be no reason , why the aer should flow from above down upon it in the first moment of its delapse . besides , when a stone projected upward , hath attained to the highest point of its ascent , at which there seems to be a short pause , or respite from motion , caused by the aequilibration of the two contrary forces , the movent and resistent : why doth not the stone absolutely quiesce in that place , there being in the aer no cause , which should rather depel it ●ownward , then elevate it upward ? these considerations , we ingenuously confess , are potent , and put us to the exigent of exploring some other external principle , beside the motion of restitution in the aer ; such as may begin the downward motion of the stone , when gently dropt off from some convenient supporter , or when it is at the zenith or highest point of its ascent , and and at the term of its aequilibration overcome the resistence of the subjacent aer , that so it may not only yeeld to the stone in the first moment of its descent ; but by successive circulations afterward promote and gradually accelerate its motion once begun . depellent cause there can be none ; and so there must be some attrahent , to begin the stones praecipitation : and that can be no other , but a certain peculiar virtue of the whole terrestrial globe , whereby it doth not onely retain all its parts , while they are contiguous or united to it , but also retract them to it self , when by any violence they have been avulsed and separated . and this virtue may therefore be properly enough called magnetique . in nature , nothing is whole and entire , in which there is not radically implanted a certain self-conservatory power , whereby it may both contain its several parts in cohaerence to it self , and in some measure resist the separation or distraction of them ; as all philosophers , upon the conviction of infinite experiences , decree : and if so , it were a very par●ial a●s●rdity to bereave the terraqueous globe , being a body whole and entire , of the like conservatory faculty . and hence comes it , that if any parts of the earth be violently avelled from it ; by this conservatory , ( which must be attractive ) virtue , it in some measure resisteth their avulsion , and after the cessation of the avelling violence , retracteth them again ; and this by insensible emanations , or subtile threads , deradiated continually from its whole body , and hookt or fastned to them : as a man retracts a bird flown from his hand , by a line or thread tyed to its feet . by the parts of the terrestrial globe we intend not only the parts of earth and water ( the liquid part of the earth , and as blood in an animal ) nor only all stones , metalls , minerals , plants , animals , and whatever bodies derive their principles from them , such as rain , dew , snow , hail , and all meteors , vapours , and exhalations ; nor only the aer , wherewith the globe of earth is circumvested , as a quince or malacotone is periwiggd about with a lanuginous or hoary substance , ( because , if we abstract from the surface of the earth all vapours , expirations , fumes , and emanations of subtle bodies from water and other substances , which ascend , descend , and everywhere float up and down in the atmosphere , nothing can remain about the same , but an empty space , ) but also fire it self , which hath its original likewise from terrestrial matter , as wood , oyl , fat , sulphur , and other unctuous and combustible substance . because all these are bodies , which as parts of it self the earth containeth and holds together ; not permitting any of them to be avelled from its orbe , but by some force that exceeds its retentive power : and when that avellent force ceaseth , it suddainly retracts them again to it self . and , insomuch as two bodies cannot coexist in one and the same place at once ; therefore comes it to pass , that many bodie● being at once retracted toward the earth , the more terrene are brought neerer to the surface thereof , extruding and so succeeding in to the rooms of the less terrene : whence the neerer adduced and extruding bodies are accounted heavy , and the extruded and farther removed , are accounted light. secondly , that the earth is naturally endowed with a certain magnetical virtue , by which perpetually diffused in round , it containeth its parts in cohaerence , and reduceth those , which are separated from it self ; after the same manner , as a loadstone holds its own parts together , and attracts iron ( which is also a magnetique production , as gilbert ( de magnet . lib. . cap. . ) from the observation of miners , and other solid reasons , hath confirmed ) to it self , and retracts it after divulsion or separation : we say , all this may be argued from hence , that the whole globe of the earth seems to be nothing but one grand magnet . ( ) because a loadstone , tornated into a sphere , is ( more than analogically only ) a little earth : being therefore nicknamed by gilbert ( de magnet . lib. . cap. ▪ ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , terella ; insomuch as the one , so also hath the other its poles , its axis , aequator , meridian , paralels . ( ) excepting only some parts , which have suffered an alteration and diminution , if not a total amission of virtue , in the exteriors of the earth ; all parts thereof discover some magnetick impraegnation : some more vigorous and manifest , as the loadstone , and iron ; others more languid and obscure , as white clay , bricks , &c. whereupon gilbert erects his conjectural judgement , that the whole globe terrestrial is composed of two general parts , the shell , and kernel : the shell not extending it self many hundred fathoms deep ( which is very small comparatively to the vastness of its diametre , amounting to miles , italian measure ) and all the rest , or kernel , being one continued loadstone subst●ntially . ( . ) the loadstone always converteth those parts of it self toward the poles , which respected them in its mineral bed , or while it remaind united to the earth . all which are no contemptible arguments of our thesis , that the whole earth is endowed with a magnetique faculty , in order to the conservation of its integrity . whether the entrals of our common mother , and nurse , the earth , be , as gilbert would persuade us , one great loadstone substantially ; is not more impossible to prove , than impertinent to our praesent scope ▪ it being sufficient to the verisimility of our assigned cause of the perpendicular motion of terrene bodies , to conceive the globe of the earth to be a loadstone only analogically , i. e. that as the loadstone ●●th perpetually emit certain invisible streams of exile particles , or rays of subtle bodies , whereby to allect magnetical bodies to an union with it self ; so likewise doth the earth uncessantly emit certa●n invisible streams , or rays of subtile bodies , wherewith to attract all its ●●stracted and divorced parts back again to an union with it self , and there closely to detain them . and justifiable it is for us to affirm , that f●●m the terraqueous orbe there is a continual efflux , not only of vapou●s , exhalations , and such small bodies , of which all our meteors are composed ▪ nor only of such , as the general mass of aer doth consist of : but also of othe● particles far more exile and insensible , nor less subtile than tho●e , which deradiated from the loadstone , in a moment permeate the most solid marble , without the least diminution of their virtue . because , as the attractive virtue of the loadstone is sufficiently demonstrated by the effect of it , the actual attraction of iron unto it : so is it lawful for us to conclude the earth to be endowed with an attractive virtue also , meerly from the sensible effect of that vertue , the actual attraction of stones , and all other bodies to it self ; especially since no other conception of the nature of that affection , which the world calls gravity , can be brought to a cleer consistence with that notable apparence , the gradual encrease of velocity in each degree of a bodies perpendicular fall . besides , the analogy may be farther deduced from hence ; that as the virtue of the loadstone is diffused in round , or spherically , and upon consequence , its effluvia , or rays are so much the more rare , by how much the farther they are transmitted from their source or original ; and so being less united , become less vigorous in their attraction , and at large distance , i. e. such as exceeds the sphere of their energy , are languid and of no force at all : so doth the terrestrial globe diffuse its attractive virtue in round , and upon consequence , its effluvia , or rays become so much the more rare or dispersed , by how much farther they are transmitted from their fountain ; and so being less united , cannot attract a stone or other terrene body at excessive d●stance , such as the supralunary and ultramundane spaces . which that we may assert with more perspicuity , let us suppose a stone to be placed in those imaginary spaces which are the outside of the world , and in which god , had he so pleased , might have created more worlds ; and then examine , whether it be more reasonable , that that stone should rather move toward this our earth , than remain absolutely immote in that part of the ultramandan spaces wherein we suppose it posited . if you conceive , that it would tend toward the earth ; imagine not only the earth , but also the whole machine of the world to be annihilated , and that all those vast spaces , which the universe now possesseth , were as absolutely inane , as they were before the creation : and then at least , because there could be no centre , and all spaces must be alike indifferent , you will admit , that the stone would remain fixt in the same place , as having no affecctation , or tendency to this part of those spaces , which the earth now possesseth . imagine the world to be then again restored , and the earth to be resituate in the place as before its adnihilation ; and then can you conceive that the stone would spontaneously tend toward it ? if you suppose the affirmative ; you will be reduced to inextricable difficulties , not to grant the earth to affect the stone , and upon consequence , to transmit to it some certain virtue , consisting in the substantial emanations , not any simple and immaterial quality , whereby to give it notice of its being restored to its pristine situation and condition . for , how otherwise can you suppose the stone should take cognizance of , and be moved toward the earth . now , this being so , what can follow , but that stones , and all other bodies accounted heavy , must tend toward the earth , only because they are attracted to it , by rays or streams of corporeal emanations from it to them transmitted ? go to then , let us farther imagine , that some certain space in the atmosphere , were , by power supernatural , made so empty , as that nothing could arrive thereat either from the earth , or any other orbe : can you then conceive , that a stone placed in that inanity , would have any tendency toward the earth , or affectation to be united to its centre ? doubtless , no more , than if it were posited in the extramundan spaces ▪ because , having nothing of communication therewith , or any other part of the universe , the case would be all one with the stone , as if there were no earth , no world , no centre . wherefore , since we observe a stone from the greatest heighth , to which any natural force can elevate the same , to tend in a direct or perpendicular line to the earth ; what can be more rational than for us to conceive , that the cause of that tendency in the stone is onely this , that it hath some communication with the earth ; and that not by any naked or immaterial quality , but some certain corporeal , though most subtile emanations from the earth ? especially , since the aer incumbent upon the stone , is not sufficient to begin its motion of descent . if you shall yet withhold your assent from this opinion , which we have thus long endeavoured to defend ; we conjecture the remora to be chiefly this : that it seems improbable , so great a bulk , as that of a very large stone , and that 〈◊〉 such pernicity , should be attracted by such slender means , as our supposed magnetick emanations : and therefore think it our duty to satisfie you concerning this doubt . we answer ( ) that a very great quantity of iron ( proportionately ) is easily and nimbly rusht into the arms of a loadstone meerly by rays of most subtle particles , such as can be discovered no way , but by their effect . ( ) that stones , and other massy concretions have no such great ineptitude , or resistence to motion , as is commonly praesumed . for , if a stone of an hundred pound weight be suspended in the aer , by a small wier , or chord : how small a force is required to the moving of it hither ? why therefore should a greater force be required to the attraction of it downward . ( ) when you lift up a stone or other body from the earth , you cannot but observe that it makes some resistence to your hand , more or less according to the bulk thereof ; which resistence ariseth from hence , that those many magnetique lines , deradiated to , and fastned upon it , by their several deflexions and decussations , hold it as it were fast chained down to the earth , so that unless a greater force intervene , such as may master the earth retentive power , and break off the magnetique lines , it could never be avelled and amoved from the earth . and hence is it , that by how much the greater force is imprest upon a stone , at its projection upward ; by so many more degrees of excess doth that imprest force transcend the force of the retentive magnetique lines , and consequently to so much a greater altitude is the stone mounted up in the aer : and è contra . which is also the reason , why the imprest force , being most vigorous in the first degree of the stones ascent , doth carry it the most vehemently in the beginning ; because it is not then refracted : but afterward the stone moves slower and slower , because in every degree of ascention , it looseth a degree of the imprest force , until at length the same be so diminished , as to come to an aequipondium with the contrary force of the magnetique rays of the earth detracting it downward . lastly , from hence is it , that the perpendicular delapse of most bodies , though of far different weights , is observed to be aequivelox : contrary to that axiome of aristotle ( . de caelo , text ) quo majus fuerit corpus , eo velocius fertur , and ( text . ) parvum terrae particulum , si elevatu dimittatur , ferri deorsum , quo major fuerit , velocius moveri ; upon which the aristoteleans have grounded this erroneous rule , velocitates gravium descendentium habere inter se eandem proportionem , quàm gravitates ipsorum , that the velocities of heavy bodies falling downward have the same proportion one to another as their gravities have . and the reason of this aequivelocity of unequal weights , seems to be this ; that of two bullets , the one of only an ounce , the other of an hundred pounds weight , dropt from the battlements of an high tower , at the same instant , though the greater bullet be attracted by more magnetique lines deradiate from the earth , yet hath it more particles to be attracted , than the lesser : so that there being a certain commensuration betwixt the force attractive , and the quantity of matter attracted ; on either part the force must be such , as sufficeth to the performance of the motion of either in the same space of time ; and consequently , both the bullets must descend with equal velocity , and arrive at the surface of the earth in one and the same moment . all which that lynceus , galilaeo well understood , when ( in the person of salviatus ) desiring to calculate the time , in which a bullet might be falling from the concave of the moon to our earth ; and sagredus had said thus to him , sumamus igitur globum determinati with the great body or globe thereof ; yet is it not congregative of the whole globe to any thing else , as if the globe of the earth were to be united to the moon , or any other orbe in the world. nor can it be affirmed , that gravity , or this virtue to motion direct , is conceded to the terraqueous orbe , to the end it should , at the creation , carry it self to that place , which is lowest in the universe ; or being there posited , constantly retain it self therein : since in the universe is neither highest , nor lowest place , but only respectively to the site of an animal , and chiefly of man , whose head is accounted the highest , and feet the lowest part ; in the same manner as there is no right , nor left side in nature , but comparatively to the site of the parts in mans body , and in reference to the heavens . for , those lateralities are not determined by any general and certain standard in nature : but variously assigned according to our imagination . the hebrews , chaldeans , and persians , confronting the sun at his arising in the east ; place the right side of the world in the south : as likewise did all the roman southsayers , when they took their auguries . the philosopher takes that to be the east , from whence the heavens begin their circumgyration : and so assigns also the right hand to the south . the astronomer , regarding chiefly the south and meridian sun , accounts that the dextrous part of heaven , which respecteth his right hand , and that 's the west . and poets , differing from all the rest , turn their faces to the west , and so assign the term of right to the north : for otherwise ovid must be guilty of a gross mistake in that verse , utque duae dextrá zonae , totidemque sinistrâ . hence is it , that as the east cannot be the right side of the world , unless to him , who faceth the north : so is the vertical point of the world not to be accounted the highest part of the universe , but onely as it respecteth the head of a man standing on any part of the earth ; because , if the same man travail to the antipodes , that which was before the highest , will then be the lowest part of the world. this considered , we must praefer that solid opinion of plato , that in the world there is an extreme , and a middle place , but no highest and lowest ; to that meerly petitionary one of aristotle , that all bodies tend toward the centre of the earth , as to the lowest place in the universe . how , saith the offended peripatetick , the meerly petitionary opinion of aristotle ? why , do not all men admit that to be the lowest part of the world , which is the middle or centre thereof ? and is not that the centre of the earth ? and our reply is , that , indeed , we can admit neither . ( ) because , should we allow the world to have a middle , or centre ; yet is there no necessity , that therefore we should concede the centre to be the lowest place in the world ▪ no more than that the navil , or central part of a man should therefore be the lowest part . for , to speak like men , who have not enslaved their reason to praejudice ; what is opposed to the mi●dle , is not suprem , but extreme : and highest and lowest are opposite points in the same extreme . so likewise in the terrestrial globe , whose middle part we account not the lowest , but the contrary point in the sphear : since , otherwi●e we must grant the earth to have a double infinity , one in regard of its centre , the other in respect of the extreme points of it● 〈◊〉 ▪ according to which the antipodes are lowest to us ▪ and we 〈◊〉 to them . ( ) wh● 〈◊〉 praetend to demonstrate ▪ that there is an ●xtreme in the universe ▪ 〈…〉 ●here be , ●o determine wher●●nd wh●t it is : ●nd upon consequence ▪ 〈◊〉 the universe hath an● centre , and wher● that centre is . t is mo●●●han galilaeo durst ▪ as appears b●●hat his modest confession ▪ n●scimus 〈…〉 ubi sit universi centrum , n●q●● an si●● quodque , si maxime d●tur ▪ aliud 〈…〉 nisi pun●tum imaginari●m , adeoque nihilum , omni facul●ate 〈…〉 . ( 〈◊〉 cosmici dialog . p●g . ) besides , we see i● to be ▪ an●●●on very good ground● , d●●put●●●mongst the most curious an● learn●● 〈◊〉 o●●he world ▪ whether the ●●xt star● are m●ved about the earth , or th●●arth by a diurnal motion upon it● own a●is ▪ whether the ●ix● stars 〈…〉 one and the same con●ave superfi●● : or rath●● ( as the planets ▪ which ●●●●i●hstanding the deluded sight , are demonst●●ted not to be in on● ▪ bu● 〈◊〉 sphere● som● farther ●rom ▪ some ne●r●● to the earth ▪ disper●e● 〈…〉 immense space ▪ for ▪ from he●ce ▪ that th● distance betwixt 〈…〉 u● i● so vast ▪ th●t our sight not discerning the large spaces intercepted 〈…〉 them in the●● several orbe● ▪ they all appe●●e at the same distanc● ▪ 〈…〉 same ●ircum●●rence ▪ wo●● c●ntre must be there ▪ wher● th● eye 〈…〉 sel● about ▪ doth behold them : so that in whatsoever part of the 〈◊〉 ●pace o● th● world ▪ whether in the moon ▪ sun , or any othe● orb ▪ 〈◊〉 ●hall imagin● your sel● to be placed ; still you must , according to 〈…〉 o● your sight , judge the world to be spherical , an● that you 〈◊〉 in the ver● centre of that circumference , in which you conceive all th● 〈◊〉 stars t● be constitute . trul● ▪ 〈◊〉 worthy th● admiration of a wise man , to obser●e , that the very plane●● 〈◊〉 admitted by the aristoteleans to have cert●●n motions 〈…〉 be moved in such gyres , as have not their centres in the 〈…〉 immensly distant from it : and yet that the same persons 〈…〉 contradict th●mselve● ▪ as to account that the centre o● the 〈…〉 common centre of the world , about which all the coelest●al 〈…〉 dif●●culties perpended ▪ w● cannot infall●bl● 〈…〉 earthy b●●ie● , when descending in direct line● to 〈…〉 toward the centre of the wor●d : and thoug● the● 〈…〉 toward the centre of the world , yet doth that seem 〈…〉 is also by accident , that they are carried towa●● the 〈…〉 earth ▪ in which as being a meer imagin●ry point , the● 〈…〉 attain quiet . for , per se ▪ they are carried towar● the 〈…〉 who le ▪ or princip●e ; and having once attained there●● , 〈…〉 as they no more seek to pass on from thenc● 〈…〉 ●entre ▪ tha● an infant received into his nurses armes or lap ▪ 〈…〉 into he● entrals : and meerly per accidens is it , that they 〈…〉 the centre of the earth ▪ because tending in the neeres● 〈…〉 line to the place o● their quiet , they must be directed 〈…〉 , since if we suppose that direct line to be continued , it must 〈…〉 the centre of the earth . and thus have we left no stone 〈…〉 all aristotles theory of gravity , which is , that weight is a quality es●●ntially inhaerent in all terrene concritions , whereby they spontan●ous●y 〈◊〉 ●oward the centre of the terrestrial globe , a● to the common cen●●e 〈…〉 place in the vniverse . the whole remainder of our praes●●● 〈◊〉 ▪ the●e●o●e , concerns our farther confirm●tion of that 〈…〉 of gravity , which we have espoused ; which is ▪ 〈…〉 meer effect of the magnetique attraction of the earth . let us therefore once more resume our argument à simili , considering the analogy betwixt the attraction of iron by a loadstone , and that of terrene concretions by the earth ; not only as to the manner of their respective attractions , but cheifly as to the parity of reasons in our judgements upon their sensible effects . when a man holds a plate of iron of or ounces weight , in his hand , with a vigorous loadstone placed at convenient distance , underneath his hand ; and finds the weight of the iron to be encreased from ounces to pounds : if aristotle on one side should tell him , that that great weight is a quality essentially inhaerent in the iron , and kepler or gilbert , on the other , affirm to him , that that weight is a quality meerly adventitious , or imprest upon it by the attractive influence of the loadstone subjacent ; 't is easie to determine , to which of those so contrary judgements he would incline his assent . if so , well may we conceive the gravity of a stone , or other terrene body , to belong not so much to the body it self , as to the attraction of that grand magnet , the terraqueous globe lying underneath it . for , supposing that a loadstone were , unknown to you , placed underneath your hand , when you lifted up a piece of iron from the earth ; though it might be pardonable for you to conclude , that the great weight , which you would observe therein , was a quality essentially inhaerent in the iron , when yet in truth it was only external and attractitious ; because you were ignorant of the loadstone subjacent ; yet , if after you were informed that the loadstone was placed underneath your hand , you should persever in the same opinion , the greatest candor imaginable could not but condemn you of inexcusable pertinacity in an error . thus also your ignorance of the earths being one great loadstone may excuse your adhaerence to the erroneous position of aristotle , concerning the formal reason of gravity ; but , when you shall be convinced , that the terrestial globe is naturally endowed with a certain attractive or magnetique virtue , in order to the retention of all its parts in cohaerence to it self , and retraction of them when by violence distructed from it , and that gravity is nothing but the effect of that virtue ; you can have no plea left for the palliation of your obstinacy , in case you recant not your former persuasion . nor ought it to impede your conviction , that a far greater gravity , or stronger attractive force is imprest upon a piece of iron by a loadstone , than by the earth ; insomuch as a loadstone suspended , at convenient distance , in the aer , doth easily elevate a proportionate mass of iron from the earth ▪ because this gradual disparity proceeds only from hence , that the attractive vertue is much more collected or united in the loadstone , and so is so much more intense and vigorous according to its dimensions , than in the earth , in which it is more diffused ; nor doth it discover how great i● is in the ●ingle or divided parts , but in the whole of the earth . thus , if you lay but one grain of salt upon your tongue , it shall affect the same with more saltness , than a gallon of sea-water : not that there is less of salt in that great quantity of sea water , but that the salt is therein more diffused . but to lay aside the loadstone and its correlative , iron , and come to our taste and incomparative argument ; since the velocity of the motion of a stone falling downward , is gradually augmented , and by the accession of new degrees of gravity , grows greater and greater in each degree of its descen● 〈◊〉 that augmentation , or accession of gravity , and so of veloc●●● ▪ seems no● so reasonably adscriptive to any other cause , as to this , that it is the attraction of the earth encreasing in each degree of the stones appropinquation to the earth , by reason of the greater density or union of its magnetique rayes : what can be more 〈◊〉 than that the first degree of gravity , belonging to a stone no● 〈◊〉 moved , should arise to it from the same attraction of the 〈◊〉 when , doubtless , it is one and the same gravity that causeth both those effects ; the same in specie , though not in grad●● : 〈◊〉 no quality can be better intended , or augmented , than by an accession of more degrees of force from the same quality . sect . iii. lastly ▪ as concerning levity , which is vulgarly reputed the 〈…〉 gravity , and by aristotle defined to be a quality inhaerent in 〈…〉 bodies ▪ whereby they spontaneously tend upward ; we understand it to be nothing a less gravity : and so that gravity and 〈◊〉 are qualities of concretions , not positive , or absolute ▪ but 〈◊〉 comparative , or respective . for , the same body ma● be 〈…〉 be heavy , in respect to another that is lighter ; and light ▪ 〈…〉 to another that is heavier . for example , let us compare a stone ▪ water , oyle , and fire ( which we have formerly annumerated 〈◊〉 terrene concretions ) one to another ; to the end that our 〈◊〉 may be both illustrated and confirmed at once . water ▪ we 〈◊〉 being poured into a ves●el , immediately descends to the bottom 〈…〉 and if permitted to settle , doth soon acquiesce : but ▪ upon 〈◊〉 ●ropping of stone into the same vessel , as the stone descends ▪ 〈◊〉 water ascends proportionately to give it room at the bottom . and oyle , infused into a vessel alone , doth likewise instantly 〈◊〉 and remains quiet at the bottom thereof : but , if water be poure●●●ereupon ▪ the oyle soon ascends , and floats on the surface of the water . if the vessel be repleat only with aer , the aer 〈◊〉 therein : but when you pour oyle into it , the aer instantly as●ends , and resignes to the oyle . lastly , thus fire would be ●mmediately incumbent upon the surface of the earth , and there 〈◊〉 ; but that the aer , being circumstant about the superfice 〈◊〉 the terrestria● globe , and the more weighty body of the two 〈◊〉 extrude it thence by depressure , and so impell ●t upwards 〈◊〉 make room for it self beneath . and thus are all these bodies 〈…〉 and light , comparatively or respectively . the 〈…〉 all is the stone , as being the most strongly attracted 〈…〉 earth : or , is the least light among them all , as being 〈…〉 abduced from the earth . and , water , which is light , 〈…〉 of the stone , is yet ▪ heavy in compa●●son of oyle : seu fumum rapi in sublime , & extrudi suum extra locum , ideoque statim langues●●re tanquam confessâ causâ violentiae , quae terrestri materiae illata fuit● quapropter levitatem non dari , aut non esse connaturalem hisce corporiubs . conclude also , with us ; that in the earth indeed , there are direct motions upward and downward : but those motions are proper only to the parts ( as gravity and levity are likewise proper only to the parts ) not to the whole , or globe of the earth . chap. xii . heat and cold . sect . i. the genealogy of those sensible qualities of concretions which arise from either of the three essential proprieties of atoms , in its single capacity , thus far extending it self ; here begins that other of those , which result from any two , or all of the same proprieties , in their several combinations , or associations . of this order , the first are heat , cold , humidity , siccity ; which though the schools , building on the fundamentals of their dictator , aristotle , derive immediately and solely from the first qualities of the vulgar elements , fire , aer , water , earth ; yet , because those reputed elements are but several compositions of the universal matter , and so must desume their respective qualities from the consociated proprieties of the same ; and because the original of no one of those qualities can be so intelligibly made out from any other principles : therefore doth our reason oblige us , to deduce them only from the magnitude , figure , and motion of atoms . concerning the first of this quaternary , heat ; we well know , that it is commonly conceived and defined by that relation , it bears to the sense of touching in animals ; or , as it is the efficient of that passion , or acute pain , as plato ( in timaeo ) calls it , which fire , or immoderate heat impresseth upon the skin , or other organ of touching ; yet , forasmuch as this effect , which it causeth in the sensient part of an animal , is only special and relative ; therefore ought we to understand its nature , from some general and absolute effect , upon which that special and relative one depends , and that is the penetration , discussion and dissolution of concretions . to come therefore to the determination of its essence , by the explanation of its original ; by heat , as from our praecedent disquisition of the origine of qualities in general may be praesumed , we do not understand any aristolet●●● , i. e. naked or immaterial quality , altogether abstract from matter : but certain particles of matter , or atoms , which being essentially endowed with such a determinate magnitude , such a certain figure , and such a 〈◊〉 motion , are comparated to insinuate themselves into concrete bodies , to penetrate them , dissociate their parts , and dissolve their contextur 〈◊〉 to produce all thus mutations in them , which are commonly 〈…〉 heat , or fire . not that we gainsay , but heat may be considered 〈…〉 , or as it is a certain peculiar manner , without which a substanc● 〈…〉 which sense anaximene● ( apud plutarch , de 〈…〉 allowed to have spoken tollerably , when he said , 〈…〉 substantial , but affirm only , that it is not 〈…〉 independent upon matter ●as most have 〈◊〉 〈…〉 ought else , in reality , but atoms themselves , 〈…〉 concretions ; so of all their faculties 〈…〉 motion , so all action ought to be imputed . 〈…〉 from which we derive this noble and most 〈…〉 be not hot essentially ; yet do they deserve the 〈…〉 of heat , or calorifick atoms , insomuch as they have 〈…〉 to create heat , i. e. cause that effect , which consisteth 〈…〉 discussion , exsolution . likewise , those bodies which 〈…〉 such atoms , and may emit them from themselves ; ought also to be 〈…〉 hot , insomuch as that by the emission of their calorifick 〈…〉 empowered to produce heat in other bodies : and 〈…〉 actually emit them , i. e. give their calorifick atoms liberty 〈…〉 motions , after exsilition ; then may they be 〈…〉 or formally hot , as the schools phrase it ; but which 〈…〉 them within themselves , and hinder their exsilition , they are 〈…〉 to the first of these difference● , we are to refer 〈…〉 second , not only all those things , which physicians call 〈…〉 such as wine , euphorlium , peper , &c. but 〈…〉 , combustion , incalescence and the 〈◊〉 〈…〉 objected , such as wood , resine , wax , 〈…〉 be conceived to contain igneous or calorifick 〈…〉 or imprisonment in concretions , 〈…〉 so not produce heat ; but immediately 〈…〉 , or emption , they manifest their nature 〈…〉 . 〈…〉 what kind of atoms these calorifick ones are , and 〈…〉 heat depends ; democritus , epicurus , 〈…〉 atomists unanimously tell us , that they are exile in 〈…〉 in figure , most swift in motion . and this upon 〈…〉 that they must be most exile in bulk , is 〈…〉 that no concretion can be so compact and solid , 〈…〉 find some pores or small inlets , whereat to insinuate 〈…〉 of it , and penetrate thorow its substance ; 〈…〉 a number , as is required , to the total dissolution of its contexture , as in the adamant , which as naturalists affirm , no fire can demolish or dissolve . ( . ) that they ought to be spherical in figure , is probable , yea necessary from hence ; that of all others they are most agile , and evolve themselves quoquoversùm , on all parts of the concretion , into which they are admitted . and geometry teacheth , that no figure is so easily moved , as a sphere , whether naturally , or violently . first , naturally ; because , by how much neerer to a sphere the figure of any solid body approacheth , by so much the more speedily doth it descend , as is observed of globular stones in water : and a round stone rowles it self farther and swifter downe hill , than a plane or angular one . secondly , violently , because a globular stone may be projected much farther , than one of any other figure . this is also evident in the motion of volutation ; so that the line of direction to the centre of the world ( if any such there be ) consisting in the axis of the globe , the motion of it is most hardly refracted and arrested . for , there are points , thorowe which the direct imaginary line , in which alone a globe can quiesce , must pass , viz. the centre of the world , the centre of gravity in the globe , and the point of contact : and if either of these be without , or beside the line of quiet , a globe once moved shall never rest , but be continually moved , until all the points be in the line of direction . furthermore , how easie it is to impel● a globe , is demonstrable meerly from hence , that being posited upon a perfect plane , it can touch the same but only in one point ; and so relying upon that point , may most easily be deturbed from that slender support ; but in all other figures the reason of innixion or relying , is quite contrary . lastly , as a sphere doth most easily admit an imprest motion ; so doth it longest retain the same , most violently press upon other occurring bodies , and most equally dispence its conceived force ; as hath been profoundly demonstrated by magnenus ( in theoricae militaris lib. . theorem . . & ) ( ) and that they must be also superlatively swift in motion , may be argued not only à posteriori , from the impetuous discussion and separation of the particles of bodies by them , and their uncessant aestuation among themselves arietating each other : but also à priori , because , being spherical , they are most mobile . thus much , at least in importance , we have from philoponus ( in physic . ) where he saith , sphaericus atomos , tanquàm facillimè mobiles , esse cal●ris , ignisque caussas ; quatenus enim sunt facilè mobiles , dividunt , sub●●mque velociùs : id quippe ignis proprium est , & dividere , & moveri facilè posse . and albeit plato would not have the atoms of fire to be spherical , but pyramidal ; because having most exile points , slender angles ; and acute sides , they might be more accommodate for penetration or su●ingression : yet , to the division or cutting of bodies , he requires 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . the exiquity of particles , and celerity of motion . so that the patrons of atoms praesuming the calorifick atoms to be extreamly exile , i. e as small as plato supposeth the points and angles of his pyramids to be : we do not perceive any considerable difference betwixt their opinion and his . but before we take off our pen from this subject , we are to advertise ; that indeed all atoms , of their own nature , are inexcogitably swift ; and so that our assertion of the superlative velocity of calorifick atoms , doth appertain only to atoms as they are in concretions , where their native velocity and agility is retarded and diminished by reciprocal cohaerence and revinction . and , therefore , seeing that all atoms , agitated by their essential mobility , are in perpetual attempt to extricate themselves from concretions , that so they may attain their primitive freedom of motion ; that none can so soon extricate and disengage themselves ; as those that are spherical ; because such cannot be impeded by the small hooks , or angles of others . cum enim sphaera ●mnibus angulis careat , nihil hamati , aut retinentis offendet , facilè permeabit , & quoquoversus ad naturae penetrabit instituta , dividet instar cunei , & ( quod nulli alteri figurae conting●t ) contactu puncti labefaciens planum , statim amplo sinu sibi viam facit , cum nihil habet angulosi , quo possit detineri ; quod ejus activitati necessarium suit : saith magnenus ( de atom . lib. cap. . ) as also , that we speak the dialect of democritus , when we call these calorifick atoms , sometimes the atoms of heat , sometimes the atoms of fire , indiscriminately ; because heat and fire know none but a gradual difference ; at least , because heat , in a general sense , implies all degrees , and fire , in a special , the highest degree of heat ; aristotle himself ( meteor . ) excellently defining heat to be nothing else , but caloris hyperbole , the excess of heat . the proprieties , or requisite conditions of these calorifick atoms , being thus explored ; our next enquiry must be concerning the manner of their emancipation , or expedition from the fetters of concretions . we observe , therefore , that the atoms of fire , imprisoned in concretions , have two ways of attaining liberty . ( . ) by evocation , or the assistance of other atoms of the same nature ; when such invading and insinuating themselves into the centrals of a body , do so dissociate its particles , as that dissolving the impediments or chains of the igneous atoms therein contained , they not only give them an opportunity , but in a manner sollicite them to extricate themselves . and by this way do the atoms of fire , included in wood , wax , turpentine , oyle , and all other inflammable concretions , extricate themselves , when they are set on fire ; the sparks or flame , wherewith they are accensed , penetrating their contexture , and removing the remoraes , which detained and impeded their internal atoms of fire , and exciting them to emption : which thereupon issue forth in swarms , and with the violence of their exsilition drive before them , in the apparence 〈◊〉 fuliginous ▪ exhalations or smoak , those dissimilar particles , which supprest and incarcerated them , during the integrity of the concretion . ( . ) by motion , or concussion ; and that either intestine , or external . first , intestine ; when , after many evolutions , the igneous atoms , included in a body , do of themselves dissociate and discuss those heterogeneous masses , wherein they were imprisoned : which they chiefly effect , when after some of them have by spontaneous motion attained their freedom , if any thing be circumstant , which hath the power of repelling them , as 〈◊〉 ; for , in that case , returning again into the centrals of the body , from whence they came ; and so associating with their fellows , promote the discussion of the remaining impediments , and concur to a general emption . from this motion ariseth that heat , or fire , which is vulgarly ascribed to the antiperistasis , or circumobsistence of cold ; as , for example , when a heap of new corn , or mowe of green hay , being kept too close , during the time of its fermentation , or sweating ( as our husbandmen 〈◊〉 , sets it self on fire : the cold of the ambient aer , repelling the atoms of 〈◊〉 which otherwise would expire insensibly ) back again into it ; and so causing them to unite to their fellows : and upon that consociation they suddainly engage in a general cumbustion , and dissolving all impediments , 〈◊〉 their liberty . hence also proceed all those heats , which are observed in fermentation , putrifaction and all other intestine commotions and mutations of bodies . hither likewise would we refer that so generally believed phaenomenon , the warmness of fountains , cellars , mines , and all subterraneous fosses , in winter : but that we conceive it not only superfluous , but also of evil consequence in physiology , to consign a cause , where we have good reason to doubt the verity of the effect . for , if we strictly examine the ground of that common assertion , we shall find it to consist only in a misinformation of our sense ; i. e. though springs , wells , caves , and all subterraneous places are really as cold in winter , as summer ; yet do we apprehend them to be warm : because we suppose that we bring the organs of the sense of touching alike disposed in winter and summer , not considering that the same thing doth appear cold to a hot , and warm to a cold hand , nor observing , that oyle will be conglaciated , in winter , in subterraneous cells , which yet appear warm to those , who enter them , but not in summer , when yet they appear cold. secondly , by motion external , when a sawe grows hot , by continuall affriction against wood , or stone ; or when fire is kindled by the long and hard affriction of dry sticks , &c. this is manifest even from hence , that unless the bodies agitated , or rubbed against each other , are such as contain igneous atoms in them ; no motion , however lasting and violent , can excite the least degree of heat in them . for , water agitated most continently and violently , never conceives the lest warmth : because it is wholly destitute of calorifick atoms . lastly , as for the heat , excited in a body , upon the motion of its whole , whether it be moved by it self , or some external movent ; of this sort is that heat , of which motion is commonly affirmed to be the sole cause : as when an animal grows hot with running , &c. and a bullet acquires heat in flying , &c. and thus much concerning the manner of emancipation of our calorifick atoms . the next thing considerable , is their peculiar seminarie or conservatory ; concerning which it may be observed , that the atoms of fire cannot , in regard of their extreme exility , sphaerical figure , and velocity of motion , be in any but an unctuous and viscous matter , such whose other atoms are more hamous , and reciprocally cohaerent , than to be dissociated easily by the intestine motions of the calorifick atoms ; so that some greater force is required to the dissolution of that unctuousness and tenacity , whereby they mutually cohaere . and hereupon we may safely conclude , that an unctuous substance is as it were the chief , nay the sole matrix or seminary of fire or heat ; and that such bodies only , as are capable of incalescence and inflammation , must contain somewhat of fatness and unctuo●ity in them . sometimes , we confess , it is observed , that concretions , which have no such unctuosity at all in them , as water , are hot , but yet we cannot allow them to be properly said to wax hot , but to be made hot ; because the principle of that their heat is not internal to them , but external or ascititious . for instance ; when fire is put under a vessel of water , the small bodies , or particles of fire by degrees insinuate themselves thorowe the pores of the vessel into the substance of the water , and diffuse themselves throughout the same ; though not so totally , at first , as not to leave , the major part of the particles of the water untoucht : to which other igneous atoms successively admix themselves , as the water grows hotter and 〈◊〉 . and evident it is , how small a time the water doth kee●●ts acquired heat , when once removed from the fire : because , th●●toms of heat being meerly adventitious to it , they spontaneousl● 〈◊〉 it one after another , and leave it , as they found it , cold only 〈◊〉 alteration ▪ they cause therein , that they diminish the quantity the 〈◊〉 ▪ insomuch as successively as●ending into the aer , they carry along 〈◊〉 them the more tenuious and moveable particles of the water , in 〈◊〉 ●pparence of vapours , which are nothing but water diffused , 〈…〉 . bu● , 〈…〉 we affirm ▪ that only unctuous bodies are inflammable ▪ be g●●●rally true ▪ whence comes it , that amongst unctuous and 〈…〉 , some more easily take fire ▪ than others ? the 〈…〉 is this ▪ that the atoms of fire , incarcerated , in ●ome 〈◊〉 ▪ are not so deeply immerst in , nor so opprest and 〈…〉 other heterogenous particles of matter , as in others ▪ 〈…〉 the l●berty of eruption much more easily . thus 〈…〉 kindled , than green ▪ because , in the green ▪ the a●ueous 〈…〉 , surrounding and oppressing the atoms of fire therein containe● 〈◊〉 first t● be discussed and attenuated into vapours : but , in the 〈◊〉 time ▪ b● the mediation of the warmth in the ambient ae● ▪ hath 〈…〉 that luxuriant moysture , so that none but the 〈…〉 ▪ o● un●tuous part , wherein the atoms of fire have their 〈…〉 , remains to be discussed ; which done , the atoms of 〈…〉 issue forth in swarms , and discover themselves in 〈…〉 spirit of wine is so much the sooner inflammable , by how much 〈◊〉 more pure and defaecated it is ; because the igneous atoms 〈…〉 concluded , are delivered from the greater part of that 〈…〉 humidity , wherewith they were formerly ●urrounded 〈…〉 ▪ on the contrary , a stone is not made combustib●e 〈◊〉 great ●●fficulty ▪ because the substance of it is so compact , as 〈…〉 unctuous humidity is long in discussion . we ●ay , a stone 〈…〉 , or arenaceous one , because such is destitute of all 〈◊〉 , and so of all igneous particles : but , a lime-stone , 〈…〉 capable of reduction to a calx : or a flint out of which by 〈◊〉 against steel , are excussed many small fragments , plentifully 〈◊〉 atoms of fire . the 〈◊〉 and origine of heat being thus fully explicated , according 〈…〉 most ver●imilous principles of democritus , epicurus , and their 〈…〉 , that we progress to those porifmata or 〈◊〉 , which from thence result to our observation ; and the 〈…〉 some most considerable problems , retaining to the same 〈◊〉 , suc● especially as have hitherto eluded the folutive 〈…〉 any other hypothesis , but what we have here 〈◊〉 . 〈…〉 , as the atoms of heat , which are always 〈…〉 ●nctuous matter , doe , upon the acquisition of 〈…〉 ●orth with violence , and insinuating themselves into bodies , which they meet withal , and totally pervading them , dissociate their particles , and dissolve their compage or contexture . hence is it manifest , that rarefa●tion , or dilatation is upon good reason accounted the proper effect of heat ; since those parts of a body , which are conjoyned , cannot be disjoyned , but they must instantly possess a greater part of space ( understand us in that strict sense , which we kept our selves to , in our discourse of rarefaction and condensation ) than before . hence come● it , that water in boyling , seems so to be encreased , that what , when cold , filled scarce half the caldron , in ebullition cannot be contained in the whole , but swells over the brim thereof . hence is it also , that all bodi●● attenuated into fume , are diffused into space an hundred , nay sometimes a thousand degrees larger than what they possessed before . from this consectary we arrive at some problems , which stand directly in our way to another ; and the first is that vulgar one , why the bottom of a caldron , wherein water , or any other liquor is boyling , is but moderately warm , at most not so hot , as to burn a mans hand applyed thereto ? the cause of this culinary wonder 〈◊〉 our housewifes account it ) seems to be this ; when the atoms of he●t , passing through the pores in the bottom of the caldron into the water , do ascend through it , they elevate and carry along with them some particles thereof : and at the same time , other particles of water , next adjacent to them , sink down , and instantly flowe into the places deserted by the former , which ascended , and insinuate themselves into the now laxarated pores in the bottom of the caldron . and though these are soon repelled upwards by other atoms of fire ascending thorowe the pores of the vessel● , and carried upwards , as the former , yet are there other particles of water , which sinking down , insinuate also into the open pores of the vessel , and by their confl●x or downward motion , much refract the violence of the subingredient atoms of fire : and so , by this ●●ciffitude of heat and moysture , it comes to pass , that the heat cannot be diffused throughout the bottom of the caldron , the humidity ( which falls into the pores of it in the same proportion , as the heat passeth thorow them ) hindering the possession of all ●ts empty spaces by the invading atoms of fire . nor doth it availe to the contrary , that the water which insinuates into the pores of the vessel , is made hot , and so must calefie the same , in some proportion , as well as the fire underneath it ; because boyling water poured ●nto 〈◊〉 caldron , doth more than warm it : for , those particles of water , which successively enter into the void spaces of the vessel● , are such as have not yet been penetrated per ●i●imas , by the a●●ms of fire . for , all the cold , formerly entered into the water , ●s not at once ●iscussed , though the water be in boyling ; the 〈◊〉 arising ●nly ●rom the cohaerence of the calefied with the 〈◊〉 particles of the water . and from the same cause ●s ●t , that a sheet of the thinne●t venice paper ▪ if so 〈…〉 hold oyle infused into 〈…〉 doth endure the 〈…〉 which some cooks observing , use to fry bacon upon a sheet of paper only . secondly , why doth lime acquire an heat and great ebullition upon the affusion of water ? since , if our praecedent assertion be true , the heat included in the lime ought to be supprest so much the more , by how much the more aqueous humidity is admixt unto it . this difficulty is discussed by answering ; that the aqueous humidity of the lime-stone is indeed wholly evaporated by fire in its calcination ; but yet the pingous , or unctuous for the most part remains , so that its atoms of fire lye still blended and incarcerated therein : and when those expede themselves , and by degrees expire into the ambient aer , if they be impeded and repelled by water affused , they recoyle upon the grumous masses of the lime , and by the circumobsistence of the humidity , become more congregated ; and so upon the uniting of their forces make way for the exsilition of the other atoms of fire , which otherwise could not have attained their liberty but slowly and by succession one after another . so that all the atoms of fire contained in the lime , issuing forth together , they break through the water , calefie it , and make it bubble or boyle up ; the calefied parts thereof being yet cohaerent to the uncalefied . the third problem is , why the heat of lime , kindled by water is more intense than that of any flame whatever ? answer , that forasmuch as flame is nothing but fire rarefied , or as it were an explication , or diffusion of those atoms of fire , which were lately ambuscadoed in some unctuous matter ; and that all fire is so much more intense or vehement , by how much more dense it is , i. e. by how much the more congregated the atoms which constitute it are : therefore is the heat of lime unslaking more vehement than that of any flame , in regard the smallest grains of lime contain in them many atoms of fire , which are not so diffused or disgregated in a moment , as those in flame . so that a mans hand being waved to and fro in flame , is invaded by incomrably fewer particles of fire , than when it is dipt into , or waved through water at the unslaking of lime thereby ; the small granes of lime adhaering unto , and insinuating into the pores of the hand , the many atoms of fire invelloped in them , incontinently explicate themselves , violently penetrate and dilacerate the skin , and other sentient parts , and so produce that pungent and acute pain , which is felt in all ambustions . from the same reason also is it , that a glowing coale burns more vehemently than flame : and the coals of more solid wood , as juniper , cedar , guaiacum , ebony , oke , &c. more vehemently than those of looser wood , such as willow , elder , pine tree , &c. the like disproportion is observable also in the flames of divers fewels ; for in the flame of juniper are contained far more igneous atoms , than in that of willow : and consequently they burn so much more vehemently . true it is , that spirit of wine enflamed , is so much more ardent , by how much more refined and cohobated : yet this proceedeth from another cause ; viz. that the atoms of fire issuing from spirit of wine of the first extraction , have much of the phletegme , or aqueous moysture of the wine intermixt among them ; and so cannot be alleaged as an example that impugne's our reason of the different heats of several flames . the fourth , is that vulgar quaere , why boyling oyle doth scald more dangerously , than boyling water ? to which it is easily answered ; that oyle , being of an unctuous and tenacious consistence , and so having its particles more firmly cohaerent , than water , doth not permit the atoms of fire entered into it , so easily to transpire : so that being more agminous , or swarming in oyl , they must invade , and dilacerate the hand of a man , immersed into it , both more thickly and deeply , than those more dispersed ones contained in boyling water . which is also the reason , why oyle made fervent is much longer in cooling , than water : and may be extended to the solution of the fifth problem , viz. wherefore do metals , especially gold , when melted , or made glowing hot , burn more violently , than the fire that melteth , or heateth them ; especially , since no atoms of fire can justly be affirmed to be lodged in them , as in their proper seminary , and so not to be educed from them , upon their liquation , or ignition . for , the heat , wherewith they procure ambustion , being not domestick , but only adventitious to them from the fire , wherein they are melted , or made red hot ; the reason why they burn so extreamly , must be this , that they are exceedingly compact in substance , and so their particles being more tenacious or reciprocally cohaerent , then those of wood , oyle , or any other body whatever , they more firmly keep together the atoms of fire immitted into them : insomuch that a man cannot touch them with his finger , but instantly it is in all points invaded with whole swarms of igneous atoms , and most fiercely compunged and dilacerated . and , as for the derasion of the skin from any part of an animal , immersed into melted metal ; this ariseth partly from the total dissolution of the tenour of the skin by the dense , and on every side compungent atoms of fire ; partly from the compression and resistence of the parts of the metal , now made fluid , which are both so great , that upon the withdrawing of the member immersed into the metal , the part which is immediately prest upon by the particles thereof , is detained behind , and that 's the skin . hence also is it no longer a problem , why red h●t iron sets any combustible matter on fire ; for it is evident , that it cannot inflame by its own substance , but by the atoms of fire immitted into , and for a while reteined in its pores . and this brings us to a second consectary , viz. that as the degrees of heat are various ( physicians , indeed , allow only , and physiologists but double that number ; the former , in order to the more convenient reduction of their art to certain and established principles ; the latter , meerly in conformity to the dictates of aristotle : but neither upon absolute necessity , since it is reasonable for any man to augment their number even above number , at pleasure ) so also must the degrees of fire be various . for , since fire , even according to aristotle is only the excess of heat , or heat encreased to that height , as to burn , or enflame a thing ; if we begin at the gentle meteor called ignis fatuus ( which lighting upon a mans hand , and a good while adhereing thereto , doth hardly warm it ) or at the fire of the purest spirit of wine enflamed ( which also is very languid , for it is frequent among the irish , for a cure of their endemious fluxes of the belly , to swallow down small balls of cotton , steept in spirit of wine , and set on fire , and that many times with good success . ) we say , if we begin from either of these weak fires , and run through all the intermediate ones , to that of melted gold , which all men acknowledge to be the highest : we shall soon be convinced , that the degrees of fire are so various , as to arise even to innumerability . most true it is , in the general , that every fire is so much the more intense , by how much more numerous , or agminous the atoms of fire are , that make it : yet , if we regard only the effect , there must be allowed a convenient space of time , for the requisite motion of those atoms , and a supply of fresh ones successively to invade and penetrate the thing to be burned or enflamed . for , since the igneous atoms , exsilient from their involucrum , or seminary , and invading the extrems of a body objected to them , are subject to easy repercussion , or ( rather ) resilition from it ; therefore , to the calefaction , adustion , or inflammation of a body , it is not sufficient , that the body be only moved along by , or over the fire : but it must be held neer ▪ or in it , so long as till the first invading igneous atoms , which otherwise would recoyle from it , be impelled on , and driven into the pores of the same , by streams of other igneous atoms contiguously , succeeding and pressing upon them . and , however the space of time , be almost in assignably short , in which the finger of a man , touching a glowing coale , or melted metal , is burned ; because , the atoms of fire are therein exceeding dense and agminous , and so penetrate the skin , in all points : yet nevertheless common observation assures , that in the general a certain space of time is necessary to the effect of calefaction or ambustion ; and that so much the longer , by how much the fewer , or more disgregated the igneous atoms are , either in the body calefying , or the aer conterminous thereto . and this ( as formerly ) to the end , that the motion of the igneous atoms first assaulting the object may be continued , and a supply of fresh ones , promoting and impelling the former , be afforded from the focus , or seminary . hence is it , that a mans hand may be frequently waved to and fro in flame , without burning ; because the atoms of fire , which invade it , are repercussed , and not by a continued aflux of others driven foreward into its pores , the motion of his hand preventing the continuity of their fluor : but , if his hand be held still in the flame , though but a very short time , it must be burned ; because the first invading atoms of fire are impelled on by others , and those again by others , in a continent fluor , so that their motion is continued , and a constant supply maintained . hence comes it also , that no metal can be molten only by a flash , or transient touch of the fire ( for , we are not yet fully satisfied of the verity of that vulgar tradition , of the instantaneous melting of money in a purse , or of a sword blade in its sheath , by lightning : and if we were , yet could we assign that prodigious effect to some more probable cause ; viz. the impetuosity of the motion , and the exceeding coarctation of those atoms of fire , of which that peculiar species of lightning doth consist ) but it must be so long held in , or over the fire , as until the igneous atoms have totally pervaded its contexture , and dissociated all its particles : and therefore , so much the longer stay in the fire doth every metal require to its fusion ; by how much the more compact and tenacious its particles are . as the degrees of fire are various , as to the more and less of vehemency , respective to the more and less density , or congregation of the igneous atoms : so likewise is there a considerably variety among flames , as to the more and less of duration . concerning the causes , therefore of this variety , in the general , we briefly observe ; that flame hath its greater or less duration , respective to the ( . ) various materials , or bodies inflammable . for , such bodies , as have a greater aversion to inflammation , being commixt with others , that are easily inflammable , make their flame less durable ; as bay salt , dissolved in spirit of wine , shortens the duration of its flame , by almost a third part , as the lord bacon affirms upon exact experiment ( nat. hist. cent . . ) and contrariwise , such as approach neerer to an affinity with fire , i. e have much of unctuousness , and plenty of igneous atoms concealed therein , yield the most lasting flames ; as oyle and spirit of wine commixt in due proportions ; and spirit of salt , to a tenth part , commixt with oyle olive , makes it burn twice as long in a lamp , as oyle alone , from whence some chymists have promised to make eternal lamps with an oyle extracted from common salt , and the stone ami●nthus . ( . ) the more or less easie attraction of its pabulum , or nourishment . for , lamps , in which the flame draweth the oyle from a greater distance , always burn much longer , than candles , or tapers , where the circumference of the fewel is but small ; and the broader the surface of the oyle , or wax , wherein the wiek is immersed , so much the longer doth the flame thereof endure ; not only in regard of the greater quantity of nourishment , but of its slower calefaction , and so of its longer resistence to the absumptive faculty of the flame . since it is observed , that the coolness of the nourishment , doth make it more slowly consumable : as in candles floating in water . this was experimented in that service of our quondam english court , called all night ; which was a large cake of wax , with the wiek , set in the middest : so that the flame , being fed with nourishment less heated before hand , as coming far off , must of necessity last much longer , than any wax taper of a small circumference . ( ) various conditions of the same materials . for , old and hard candles , whether of wax , or tallowe , maintain flame much longer than new , or soft . which good houswives knowing , use no candles under a year old , and such as have , for greater induration , been laid a good while in bran , or flower . and , from the same reason is it , that wax , as being more firm and hard , admixt to tallowe and made up into candles , causeth them to be more lasting , then if they were praepared of tallowe alone . ( . ) different conditions , and tempers of the ambient aer . for , the quiet and closeness of the aer , wherein a taper burneth , much conduceth to the prolongation of its flame : and contrariwise , the agitation thereof , by winds , or fanning , conduceth as much to the shortning of it : insomuch as the motion of flame makes it more greedily attract , and more speedily devour its sustenance . thus a candle lasteth much longer in a lanthorne , than at large in a spacious roome . which also might be assigned as one cause of the long duration of those subterranean lamps , such as have been found ( if credit be due to the tradition of bapt. porta , ( lib. . magiae natural . cap. ultim . ) hermolaus barbarus ( in lib. . dio cap. . ) and cedrenus histor. compend . ) all which most confidently avouch it , upon authentique testimonies . ) in the urns of many noble romans , many hundreds of years after their funerals . here should our reader bid us stand , and deliver him our positive judgement , upon this stupendious rarity , which hath been uged by some laureat antiquaries , as a cheif argument of the transcendency of the ancients knowledge as in all arts , so in the admirable secrets of pyrotechny , above that of later ages ; as we durst not be so uncharitable , to quaestion the veracity of either the inventors , or reporters of it : so should we not be so uncivil , as not to releive his curiosity , at least with a short story , that may light him towards farther satisfaction . a certain chymist there was , not many years since , who having decocted litharge of gold , tartar , cinnaber , and calx vive , in spirit of vinegre , until the vinegre was wholly evaporated ; closely covering and luting up the earthen vessel , wherein the decoction was made , buried it deeply in a dry earth , for moneths together ( in order to more speedy maturation , expected from the antiperistasis of cold ) came at length to observe what became of his composition : and opening the vessel , observed a certain bright flame to issue from thence , and that so vehement , as it fired the hair of his eyebrowes and head . now , having furnished our reader with this faithful narrative ; we leave it to his owne determination : whether it be not more probable , that those coruscations , or flashes of light , perceived to issue from vials of earth , found in the demolisht sepulchres of the great olybius , and some eminent romans , at the instant of their breaking up by the spade , or pickaxe ; did proceed rather from some such chymical mixture , as this of our chymist ( who acquired light by the hazard of blindness ) which is of that nature as to be in a moment kindled , and yield a shortlived flame , upon the intromission of aer into the vessel , wherein it is contained ; than from any fewel , that is so slowly absumable by fire , as to maintain a constant flame , for many hundred years together , without extinction , and that in so small a vial , as the fume must needs recoyle and soon suffocate the flame . but we return from our digression , and directly pursue our embost argument . it much importeth the greater and less continuance of flame , whether the aer be warm , or cold , dry or mo●st . for cold aer irritateth flame , by circumobsistence , and causeth it burn more fiercely , and so less durably ; as is manifest from hence , that fire scorcheth in frosty weather : but warme aer , by making flame more calm and gentle , and so more sparing of its nourishment , much helpeth the continuance of it . if moist , because it impedeth the motion of the igneous atoms , and so in some degree quencheth flame , at least , makes it burn more dimly and dully ; it must of necessity advance the duration of flame : and contrariwise , drie aer , meerly as drie , produceth contrary effect , though not in the same proportion ; nay so little , that some naturalists have concluded the driness of aer to be only indifferent , as to the duration of flame . and now we are arrived at our third and last consectary ; that the immediate and genuine effect of heat , is disgregation ▪ or separation : and that it is only by accident that heat doth congregate homogeneous natures . to argue by the most familiar way of instance ; when heat hath dissolved a piece of ice , consisting of water , earth , and perhaps of gravel and many small festucous bodies commixt ; the earth , sand and other terrene parts sink downe and convene together at the bottom , the water returns to its native fluidity , and possesseth the middle region of the continent , and the strawes swim on the surface of the water : not that it is essential to the heat so to dispose them ; but essential to them , being dissociated and so at liberty , each to take it proper place , according to the several degrees of their gravity . thus also , when a mass of various metals is melted by fire , each metal , indeed , takes it proper region in the crucible , or fusory vessel : but yet the congregation of the homogeneous particles of each particular metal , is not immediately caused , but only occasioned , i. e. accidentally brought to pass by the disgregation or praecedent separation of the particles of the whole heterogeneous concretion , by heat . again , the energy of every cause in nature ceaseth , upon the production of its perfect effect ; but the effect of heat ceaseth not , when the homogenieties of the mass of ice , or metal , are congregated , but continues the same after , as before , i. e. to dissolve the compage of the metal , or ice , and dissociate all the particles thereof : for , so long as the heat is continued , so long do the ice and metal remain dissolved and fluid . this considered , what shall we say to aristotle , who makes it the essential attribute of heat , congregare homogenea , to congregate homogeneous bodies . truly , rather then openly convict so great a votary to truth of so palpable an error ; we should gladly become his compurgator , and palliate his mistake with an indulgent comment ; that in his definition of heat , to be a quality genuinely congregative of homogeneous natures , he had his eye , not upon the general effect of heat ( which he could not but observe , to disgregate the particles of all things , aswel homogeneous , as heterogeneous . ) but upon some special effect of it upon some particular concretions , such as are compounded of parts of divers natures , as wood and all combustible bodies concerning which , indeed , his assertion is thus far justifiable , that the whole bodie is so dissolved by fire , as that the dissimilar parts of it are perfectly sequestred each from other , and every one attains it proper place ; the aereal part ascending and associating with the aer , the aqueous evaporating , the igneous discovering themselves in flame , and the earthy remaining behind , in the forme of ashes . but alas ! this favourable conjecture cannot excuse , nor gild over his incogitancy ; for , the congregation of the homogenous particles of a body , dissolved by fire , in the place most convenient to their particular nature , ariseth immediately from their own tendency thither , or ( that we may speak more like our selves , i. e. the disciples of epicurus ) from their respective proportions of gravity , the more heavy extruding and so impelling upward the less heavy : and only accidentally from heat , or as it hath dissolved the caement , and so the continuity of the concretion , wherein they were confusedly and promiscuously blended together . so that truth will not dispense with our connivence at so dangerous a lapse , though in one of her choicest favorites ; chiefly , because it hath already deluded so many of her seekers , under the glorious title of a fundamental axiome : but strictly enjoynes us , to conclude ; that heat , per se , or of its own nature , is alwayes a disgregative quality ; and that it is of of meer accident , that upon the sequestration of heterogeneities , homogeneous natures are associated , rather than , è contra , that it is of meer accident , that while heat congregates homogeneous , it should disgregate heterogeneous natures , as aristotle most inconsiderately affirmed and taught . sect . ii. as in the course , so in the discourse of nature , having done with the principle of life , heat , we must immediately come to the principle of death , cold : whose essence we cannot seasonably explain , before we have proved , that it hath an essence ; since many have hotly , though with but cold arguments , contended , that it hath none at all , but is a meer privation , or nothing . that cold , therefore , is a real ens , and hath a positive nature of its own , may be thus demonstrated . ( . ) such are the proper effects of cold , as cannot , without open absurdity , be ascribed to a simple privation ; since a privation is incapable of action : for , cold compingeth all bodies , that are capable of its efficacy , and congealeth water into ice , which is more than ever any man durst assigne to a privation . and , when a man thrusts his hand into cold water , the cold he then feels , cannot be sayd to be a meer privation of the heat of his hand ; since , his hand remains as hot , if not hotter than before ; the calorifick atoms of his hand being more united , by the circumobsistence of the cold. ( . ) all heat doth concentre and unite it self , upon the antiperistasis of cold ; not from fear of a privation , because heat is destitute of a sense of its owne being , and so of fear to lose that being ; and if not , yet nothing can have no contrariety , nor activity : but , from repulsion , as we have formerly delivered . ( . ) though many bodies are observed to become cold , upon the absence , or expiration of heat : yet is it the intromission of the quality contrary to heat , that makes them so ; for , if external cold be not introduced into their pores , they cannot be so properly sayd , frigescere , to wax cold , as decalescere , to wax less hot. thus a stone , which is not hot , nor cold , unless by accident , being admoved to the fire , is made hot ; and removed from the fire , you cannot ( unless the ambient aer intromit its cold into it ) so justly say , that it growes cold , as that it grows less hot , or returnes to its native state of indifferency . ( . ) when water ( vulgarly , though untruely praesumed to be naturally or essentially cold ) is congealed into ice by the cold of the aer , it would be most shamefully absurd , to affirm , that the cold of the ice ariseth meerly from the absence of heat in the water ; because it is the essential part of the supposition , that the water had no heat before . ( . ) privation knowes no degrees ; for the word imports the totall destitution , or absence of somewhat formerly had , otherwise , in rigid truth , it can be no privation ( and therefore our common distinction of a partial , and total privation , hath lived thus long meerly upon indulgence and tolleration . ) : but cold hath its various degrees , for water is colder to the touch than earth , ice than water , &c. therefore cold is no privative , but a positive quality . the reality of cold being thus clearly evicted , we may , with more advantage undertake the consideration of its formality , and explore the roots of those attributes commonly imputed thereunto . first , therefore , we observe ; that though cold be scholastically defined by that passion caused in the organs of the sense of touching , upon the contact of a cold object ; yet doth not that special notion sufficiently express its nature : because there is a more general effect by which it falls under our cognizance ; and that is the congregation and compaction of the parts of bodies . for , since cold is the antagonist to heat , whose proper vertue it is , to discuss and disgregate ; therefore must the proper and immediate virtue of cold be , to congregate and compinge : and consequently , ought we to form to our selves a notion of the essence of cold , according to that general effect , rather than that special one produced in the sense of touching , which doth adumbrate only a relative part of it . secondly , that by cold , we understand not any immaterial quality , as aristotle and the schools after him ; but a substantial one , i. e. certain particles of matter , or atoms whose determinate magnitude and figure adapt or empower them to congregate and compinge bodies , or to produce all those effects observed to arise immediately from cold. and , as the atoms , which are comparated to the causation of such effects , may rightly be termed , the atoms of cold , or frigorifick atoms : so may those concretions , which harbour such atoms , and are capable of emitting them , be named cold concretions ; either actually , as frost , snowe , the north-wind , &c. or potentially , as nitre , hemlock , night-shade , and all other simples aswel medical , as toxical or poysonous , whose alterative virtue consisteth cheifly in cold. now , as for the determinate figure of frigorifick atoms ; our enquiries can hope for but small light from the almost consumed vaper of antiquity : for , though philoponus ( in physic . ) & magnenus ( de atomis , disput . . cap. . ) confidently deliver , that democritus assigned a cubical figure to the atoms of cold ; and endeavour to justifie that assignation , by sundry mathematical reasons : yet aristotle , a man aswell acquainted with the doctrines of his predecessors , as either of those , expresly affirms , that nor democritus , nor leucippus , nor epicurus determined the atoms of cold to any particular figure at all ; for , his words are these ( de caelo , cap. . ) 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , nihilpend● determinarunt . so , that rather than remain altogether in the dark , we must strike fire out of that learned conjecture of our master ga●sendus ; and taking our indication from the rule of contrariety , infer , that the atoms of heat being spherical , those of cold , in all reason , must be tetrahedical , or pyramidal , consisting of sides , or equilateral triangles . to make the reasonableness of this supposition duly evident , let us consider ( . ) that as heat hath its origine from atoms most exile in magnitude , spherical in figure , and so most swift of motion : so must its contrary , cold , be derived from principles of contrary proprieties , viz. atoms not so exile in magnitude , of a figure most opposite to a sphere , and so of most slow motion . ( . ) that none but tetrahedical atoms can justly challenge to themselves these proprieties , that are requisite to the essensification of cold. for ( . ) if we regard their magnitude , a tetrahedical atom may be greater than a spherical , by its whole angles : because a sphere may be circumscribed within a tetrahedon . ( . ) if the figure it self ; none is more opposed to a sphere , than a tetrahedon : because it is angular , and farthest recedeth from that infinity , or ( rather ) innumerability of small insensible sides , which a profound geometrician may speculate in a sphere . ( . ) if their mobility ; no body can be more unapt for motion , than a tetrahedical one : for , what vulgar mathematicians impute to a cube , viz. that it challengeth the palme from all other figures , for ineptitude to motion , doth indeed more rightfully belong to a tetrahedon ; as will soon appear to any equitable consideration , upon the perpension of the reasons alleagable on both parts . but here we are to signifie , that this ineptitude to motion proper to tetrahedical atoms , is not meant of atoms at liberty , and injoying freedom of motion , in the inane space ; since , in that state all atoms are praesumed to be of equal velocity : but only of atoms wanting that liberty , such as are included in concretions , and by intestine evolutions continually attempt emancipation and exsilition . ( . ) it cannot impugne , at least , not stagger the reasonableness of this conjectural assignation of a tetrahedical figure to the atoms of cold , that plato ( in timaeo ) definitely adscribeth a pyramidal figure to fire , not to the aer , i. e. to the atoms of heat , not to those of cold : because , if any shall thereupon conceive , that a pyramid is most capable of penetrating the skin of a man , and consequently of producing therein the sense of heat , rather than cold ; he may be soon converted by considering a passage in our former section of this chapter , that the atoms of heat may , though spherical , as well in respect of their extreme exility ( which the point of no pyramid can exceed ) as of the velocity of their motion , prick as sharply , and penetrate as deeply , as the angles of the smallest pyramid imaginable . to which may be conjoyned , that the atoms of cold , according to our supposition , are also capable of pungency and penetration ; and consequently that a kind of adustion is also assignable to great cold ; according to that expression of virgil ( georg. ) boceae penetrabile frigus adurit . for , in fervent frosts ( to use the same epithite , as the sweet-tongued ovid , in the same case ) when our hands are , as the english phrase is , benumm'd with cold ; if we hold them to the fire , we instantly feel a sharp and pricking pain in them . which ariseth from hence , that the atoms of heat , while by their agility and constant supplies they are dispelling those of cold , which had entred and possessed the pores of our hands , do variously commove and invert them ; they are hastily driven forth , and in their contention and egress , cut and dilacerate the flesh and skin , as well with their small points , as edges lying betwixt their points , and so produce an acute and pungitive pain . whereupon the sage sennertus ( de atomis ) grounds his advice , that in extreme cold weather , when our hands are so stupified , as that an extinction of their vital heat may be feared ; we either immerse them into cold water , or rub them in snow , that the atoms of cold , which have wedged each other into the pores , may be gently and gradually called forth , before we hold them to the fire : and this , least not only grievous pain be caused , but a gangrene ensue , from the totall dissolution of the contexture of our hands by the violent intrusion of the cold atoms , when they are forcibly impelled and agitated by the igneous ; as the sad experience of many in ruscia , groenland , the alps ▪ and other regions obnoxious to the tyranny of cold , hath taught . concerning this , helm●nt also was in the right , when he said , mechanicè namque videmus , membrum fere congelatum sub nive recalescere , & à syderatione praeservari ; quod alias aer mox totaliter congelare pergeret , vel si repente ad ignem sit delatum , moritur propter extremi alterius festinam actionem ▪ &c. ( in cap. de aere articul . ) ( . ) nor doth it hinder , that philoponus and magnenus affirm , that the atoms of cold ought to be cubical , in respect of the eminent aptitude of that figure , for constipation and compingency , the general effects of cold : because , a pyramid also hath its plane sides , or faces , which empower it to perform as much as a cube , in that respect ; and if common salt be constrictive , only because , being hexahedrical in form , it hath square plane sides , as a cube ; certainly alum must be more constrictive , because being octahedrical in form , it hath triangular plane sides , as a pyramid . besides , it is manifest , that these plane sides must so much the more press upon and wedge in the particles of a body , by how much more of the body , or greater number of its particles they touch : and that by how much more they are entangled by their angles , so much more hardly are they expeded , and so remain cohaerent so much more pertinaciously . hence comes it , that all concretions consisting , for the most part , of such figurated atoms , are adst●ictive effectually : for , interposing their particles amongst those of other bodies , that are fluid ; they make their consistence more compact and somewhat rigid , as in ice , snow , haile , hoar-frost , &c. the consignation of a tetrahedical figure to frigorifick atoms appearing thus eminently verisimilous ; to the full explanation of the nature of cold , it remains only , that we decide that notable controversy , which so much perplexed many of the ancients : viz. whether cold be an elementary quality ; or ( more plainly ) whether or no the principality of cold belongs to any one of the four vulgar elements ; and so whether aer , or water , or earth may not be conceived to be primum frigidum , as rightfully as fire is sayd to be primum calidum ? especially , since it is well known , that the stoicks imputed the principality of cold to the aer ; empedocles to water , to whom aristotle plainly assented , though he sometimes forgot himself , and affirmed that no humor is without heat ( as in . de generat . animal . cap. ● . ) ; and plutarch to earth , as we have learned from himself ( lib. de frigore primigenio . ) to determine this antique dispute , therefore , we first observe ; that it arose cheifly from a petitionary principle . for it appears , that all philosophers , who engaged therein , took it for granted , that the quality of heat was eminently inhaerent in fire , the chief of the principal or elementary substances ; and thereupon inferred , that the contrary quality , cold , ought in like manner to have its principal residence in one of the other : when , introth , they ought first to have proved , that there was such a thing as an element of fire in the universe ; which is more than any logick can hope , since the sphere of fire , which they supposed to possess all that vast space between the convex of the sphere of aer , and the concave of that of the moon , is a meer chimaera , as we have formerly intimated , and helmont hath clearly commonstrated ( in cap. de aere . ) and secondly we affirm , that as the highest degree of heat is not justly attributary to any one body more than other , or by way of singular eminency ( for , the sphere of fire failing , what other can be substituted in the room thereof ? ) but to sundry special bodies , which are capable of exciting or conceiving heat , in the superlative degree : so likewise , though we should concede , that there are principal bodies in nature , namely aer , water , earth , in each whereof the quality of cold is sensibly harboured ; yet is there no one of them , of its own nature more principally cold than other , or which of it self containeth cold in the highest degree ; but some special bodies there are , composed of them , which are capable of exciting and conceiving cold , in an eminent manner . but , in generals is no demonstration ; and therefore we must advance to particulars , and verify our assertion , in each of the three supposed elements apart . for the earth : forasmuch as our sense certifieth that it is even torrified with heat , in some places , and congealed with cold in others , according to the temperature of the ambient aer in divers climats , or as the aer , being calefied by the sun , or frigified by frost , doth variously affect it , in it superficial or exterior parts ; and so it cannot be discerned , that its external parts are endowed with one of these opposite qualities more than the other : and since we cannot but observe , that there are many great and durable subterraneous fires burning in , and many fervid and sulphlureous exlations frequently emitted , and more hot springs of mineral waters perpetually issuing from its interior parts , or bowels ; and so it is of necessity , that vast seminaries of igneous atoms be included in the entrals thereof : we say , considering these things , we cannot deny , but that the earth doth contain as many particles of heat , or calorifick atoms , both without and within , as it doth of seeds of cold , or frigorifick atoms , if not more ; and upon consequence , that it cannot be primum frigidum , as plutarch and all his sectators have dreamt . what then ; shall we conclude antithetically , and conceive that the globe of the earth is therefore essentially rather hot , than cold ? truely , no ; because experience demonstrateth , that the earth doth belch forth cold exhalations , and congealing blasts , as well as hot fumes , and more frequently : witness the north-wind , which is so cold , that it refrigerates the aer even in the middst of summer , when the rivers are exhausted by the fervor of the sun ; to which elihu , one of iobs sorry comforters , seems to have alluded , when he said , that cold cometh out of the north , and the whirlwind out of the south . all , therefore , we dare determine in this difficult argument ( the decision whereof doth chiefly depend upon experiments of vast labour and costs ) is only thus much ; that the earth , which is now hot , now cold , in its extreme or superficial parts , may , as to its internal or profound parts , be as reasonably accounted to contain various seminaries of heat , as of cold : and that the principal seeds of cold , or such , as chiefly consist of frigorifick atoms , do convene into halinitre , and other concretions of natures retaining thereto . and our reason is that halinitre is no sooner dissolved in water , than it congealeth the same into perfect ice , and strongly refrigerates all bodies , that it toucheth ; insomuch that we may not only conclude , that of all concretions in nature , at least that we have discovered , none is so plentifully fraught with the atoms , or seeds of cold , as halinitre ; but also adventure to answer that problem proposed to iob , out of whose womb came the ice , and the hoary frost of heaven , who hath gendred it ? by saying , that all our freezing and extreme cold winds seem to be only copious exhalations of halinitre dissolved in the bowels of the earth ; or consisting of such frigorifick atoms , as compose halinitre ; and this because of the identity of their effects , for the tramontane wind ( the coldest of all winds , as fabricius paduanus , in his exquisite book de ventis , copiously proveth ) which the italians call chirocco , can pretend to no natural effect , in which halinitre may not justly rival it . long might we dwell upon this not more rare than delightful subject : but , besides that it deserves a profest disquisition , apart by it self , our speculations are limited , and may not , without indecency , either digress from their proper theme , or transgress the strict laws of method . may it suffice , therefore , in praesent , that we have made it justifiable to conceive that the earth containeth many such particles , or atoms ( whether such as pertain to the composition of halinitre , or of any other kind whatever ) upon the exsilition of which the body containing them may be said to become cold , or pass from potential to actual cold : and upon the insinuation of which into aer , water , earth , stones , wood , flesh , or any other terrene concretion whatever , cold is introduced into them , and they may be said to be frigefied , or made cold. secondly , as for water ; that the praetext thereof to the praerogative of essential frigidity is also fraudulent , and inconsistent with the magna charta of right reason , may be discovered from these considerations . . when water is frozen , the ice always begins in it superfice , or upper parts , where the aer immediately toucheth it : but , if it were cold of its own nature , as is generally praesumed , upon the auctority of aristotle , the ice ought to begin in parts farthest situate from the aer , that is in the middle , or bottom , rather than at the top ; at least , it would not be more slowly conglaciated in the middle and bottom , than at the top . ( . ) in all frosts , the cold of water is encreased ; which could not be , if it were the principal seat of cold. for , how could the aer which according to the vulgar supposition , that water is the subject of inhaesion to extreme cold , if less cold , infuse into water a greater cold , than what it had before of its owne ? or , how could nitre , dissolved in water , so much augment the cold thereof , as to convert it into ice , even in the heat of summer , or by the fires side ; as is experimented in artificial conglaciations : if nitre were not endowed with greater cold than water ? ( . ) if water be formally ingravidated with the seeds of cold ; why is not the sea , why are not all rivers , nay , all lakes and standing pools ( in which the excuse of continual motion is praevented ) constantly congealed , and bound up in ribbs of ice ? whence comes it , that water doth constantly remain fluid , unless in great frosts only , when the atoms of cold , wafted on the wings of the north-wind , and plentifully strawed on the waters , doe insinuate themselves among its particles , and introduce a rigidity upon them ? certainly , it is not conform to the laws of nature , that any body , much less so eminent and useful a one as water , should for the most part remain alienated from its owne native constitution , and be reduced to it again only at some times , after long intervals , and then only for a day or two . ( . ) were cold essentially competent to water , it could not so easily , as is observed , admit the contrary quality , heat , nor in so high a degree , without the destruction of its primitive form . for , no subject can be changed from the extreme of one quality inhaerent , to the extreme of a contrary , without the total alteration of that contexture of its particles , upon which the inhaerent quality depended ; which done , it remains no longer the same : but water still remains the same , i. e. a humid fluid substance , both at the time of , and after its calefaction by fire , as before . and , therefore , that common saying , that water heated doth reduce it self to its native cold , though it be tollerable in the mouth of the people ; yet he that would speak as a philosopher , ought to change it into this , that water after calefaction , returns to its primitive state of indifferency to either heat , or cold : for , though after its remove from the fire , it gradually loseth the heat acquired from thence , the igneous atoms spontaneously ascending and abandoning it one after another ; yet would it never reduce it self to the least degree of cold , but is reduced to cold by atoms of cold from the circumstant aer immitted into its pores . what then ; shall we hence conclude , that water is essentially hot ? neither ; because then it could not so easily admit , nor so long retain the contrary quality , cold , for hot springs are never congelated . wherein therefore can we acquiesce ? truly , only in this determination , that water is essentially moist , and fluid : but neither hot , nor cold , unless by accident , or acquisition , i. e. it is made hot , upon the introduction of calorifick , and cold , upon the introduction of frigorifick atoms ; contrary to the tenent of empedocles , and aristotle . lastly , as for the aer : insomuch as it is sometimes hot , sometimes cold , according to the temperature of the climate , season of the year , praesence or absence of the sun , and diversity of winds : we can have no warrant from re●son , to conceive it to be the natural mother of cold , more than of heat ▪ but rather that it is indifferently comparated to admit either quality , according to divers impraegnation . whoever , therefore , shall argue , that because in the dogg da●es , when the perpendicular rayes of the sun parch up the languishing inhabitants of the earth in some positions of its sphere , if the north-wind arise , it immediately mitigates the fe●vor of the aer , and brings a cool relief upon its wings ; therefore the aer is naturally cold : ma● as justly infer , that the aer is naturally hot ; because , in the dead 〈◊〉 winter , when the face of the earth becomes hoary and rigid with ●r●st , if the south-wind blowe , it soon mitigates the frigidity of the aer , ●nd dissolves those fetters of ice , wherewith all things were bound up . wherefore , it is best for us to conclude , that the essential quality of the aer ▪ is fluidity ; but as for heat and cold , they are qualities meerly accidental or adventitious thereto ; or , that it is made hot , or cold , upon the commixture of calorifick , or frigorifick atoms . so that where the aer is constantly impraegnate with atoms of heat , as under the torrid zone , there is it co●stantly hot , or warme at least : where it is alternately perfused with ●●lorifick and frigorifick atoms , as under the temper●te zones ; 〈…〉 it alternately hot and cold : and where it is constantly pervaded by ●●igorifick atoms , as under the north pole ; there is it constantly cold. to put a p●●iod , therefore , to this dispute ; seeing the quality of cold is not essen●●●●ly inhaerent in earth , water , or aer , the three principal bodies of nature ; where shall we investigate its genuine matrix , or proper subject of inhaesion ? certainly , in the nature of some special bodies , or a particular species of atoms ( of which sort are those whereof salnitre is for the most part composed ) which being introduced into earth , water , aer , or any other mixt bodie , impraegnate them with cold . but , haply , you may say , that though this be true , yet doth it not totally solve the doubt ; since it is yet demandable , whether any one , and which of those three elements is highly opposite to the fourth , viz. fire ? we answer , that forasmuch as that bodie is to be accounted the most opposite to fire , which most destroyes it : therefore is water the chief antagonist to fire , because it soonest extinguisheth it . nevertheless there is no necessity , that therefore water must be cold in as high a degree , as fire is hot : for , water doth not extinguish fire , as it is cold ( since boyling water doth as soon put out fire , as cold ) but as it is humid , i. e. as it enters the pores of the enflamed body , and hinders the motion and diffusion of the atoms of fire . which may be confirmed from hence ( . ) that oyle , which no man conceives to be cold , it poured on in great quantity , doth also extinguish fire , by suffocation , which is nothing but a hindering the motion of the igneous atoms : ( . ) that in case the atoms of fire issue from the accensed matter , with such pernicity and vehemence , and reciprocal arietations , and in such swarms , as that they repel the water affused , and permit it not to enter the pores of the fewel ( as constantly happens in wild-fire , where the ingredients are unctuous , and consist of very tenacious particles . ) in that case , water is so far from extinguishing the flame , that it makes it more impetuous and raging . however , we shall acknowledg thus much , that if the principality of cold must be adscribed to one of the three vulgar elements ; the aer doubtless , hath the best title thereunto : because , being the most lax and porous bodie of the three it doth most easily admit , and most plentifully harbour the seeds of cold ; and being also subtile and fluid , it doth most easily immit , or carry them along with it self into the pores of other bodies , and so not only infrigidate , but some times congeal , and conglaciate them ; in case they be of such contextures and such particles , as are susceptible of congelation and conglaciation . the fable of the satyr and wayfering man , who blew hot and cold , though in the mouth of every school-boy , is yet scarce understood by their masters ; nay , the greatest philosophers have found the reason of that contrariety of effects from one and the same cause , to be highly problematical . wherefore since we are fallen upon the cause of the frigidity in the aer ; and the frigidity of our breath doth materially depend thereon : opportunity invites us , to solve that problem , which though both aristotle ( sect . prob . . & anaximenes ( apud plutarch . de frigore primigenio ) have strongly attempted ; yet have they left it to the conquest of epicurus principles : viz. why doth the breath of a man warme when eff●ated with the mouth wide open ; and cool , when efflated with the mouth contra●●ed ? to omit the opinions of others , therefore , we conceive the cause hereof to be only this ▪ that albeit the breath doth consist of aer , for the most part fraught with calorifick atoms , emitted from the lungs and vital organs , yet hath it many frigorifick ones also interspersed among its particles : which being of greater bulk , than the calorifick , and so capable of a stronger impuls , are by the force of efflation transmitted to greatter distance from the mouth ; because , the calorifick atoms commixt with the breath , in regard of their exility , are no sooner dischaged from the mouth , than they instantly disperse in round . wence it comes , that if the breath be expired in 〈◊〉 large stream , or with the mouth wide open ; because the circuit of the 〈◊〉 of brea●h is large , and so the hot atoms emitted are not so soon dispersed : therefore doth the stream feel warme to the hand objected there ▪ and so much the more warme , by how much neerer the hand is held to the mouth ; the calorifick atoms being less and less dissipated in each degree of remove . but , in case the breath be ●mitted with contracted lipps ; becaus●●hen the compass of the stream is small , and the force of efflation greater 〈◊〉 therefore are the calorifick atoms soon disgregated , and the frigorific● ▪ only r●main commixt with the aer , which affects the objected hand 〈◊〉 cold , and by how much farther ( in the limits of the power of efflation● 〈◊〉 hand is held from the mouth , by so much colder doth the breath appear 〈…〉 contra . that calorifick atoms are subject to more and more 〈…〉 the stream of a fluid substance , to which they are commixt , is greater and greater in circuit , may be confirmed from hence ; that if we poure ho●●●ter , from on high , in frosty weather , we shall observe a fume to issue 〈◊〉 ●scend from the stream all along ▪ and that so much the more plentifully , by how much greater the stream is . thus we use to cool burnt wine , or 〈◊〉 by frequent refunding it from vessel to vessel , or infunding it into broad and shallow vessels ; that so the atoms of heat may be the sooner disper●●● for , by how much larger the superfice of the liquor is made , by so much more of liberty for exsilition is given to the atoms of heat containe●●herein , and as much of insinuation to the atoms of cold in company 〈◊〉 the circumstant aer . thus also we cool our faces in the heat of 〈◊〉 , with fanning the aer towards us : the hot atoms being thereby 〈◊〉 , and the cold impelled deeper into the pores of the skin : which 〈…〉 the reason , why all winds appear so much the colder , by how much ●●●onger they blowe ; as de●s cartes hath well observed in these words : 〈…〉 vehementior majoris frigiditatis perceptionem , quam aer 〈…〉 corpore nostro excitat ; quod aer quietus tantùm exteriorem nostram 〈…〉 quae interi●ribus nostris carnibus frigidior est , contingat : ventus vero , ●●hementius in corpus nostrum actus , etiam in penetralia ejus adigatur , 〈◊〉 illa siut cute calidiora , id circo etiam majorem frigiditatem ab ejus conta●●● percipiunt . in our prece●ent article , touching the necessary assignatin of a tetrahedical figure 〈…〉 atoms of cold , we remember , we said ▪ that in respect of their 〈…〉 or plane faces , they were most apt to compinge , or bind in the particle 〈◊〉 all concretions ▪ into which they are intromitted ; and from thence we shal●●●ke the hint of inferring three noble consectaries . ( . ) that 〈◊〉 snow , hail , hoarfrost , and all congelations , are made meerly by th●●●●romission of frigorifick atoms among the particles of 〈…〉 , being once insinuated and commixt among them , in sufficie●● 〈…〉 alter their fluid and lax consistence into a rigid and compact , i. e. they congeal them . ( . ) that 〈…〉 , or trembling sometimes observed in the members of 〈…〉 that rigor , or shaking , in the beginning of most putri● 〈…〉 when the fits of intermittent fevers invade , are chiefly cause● 〈◊〉 frigorifick atoms . for , when the spherical atoms of heat , which swarm in and vivifie the bodies of animals , are not moved quaquaversùm in the members with such freedom , velocity , and directness excentrically , as they ought ; because , meeting and contesting with those less agile atoms of cold , which have entred the body , upon its chilling , their proper motion is thereby impeded : they are strongly repelled , and made to recoyle towards the central parts of the bodie , in avoydance of their adversary , the cold ones ; and in that tumultuous retreat , or introcession , they vellicate the fibres of the membranous and nervous parts , and so cause a kind of vibration or contraction , which if only of the skin , makes that symptome , which physicians call a horror ; but if of the muscles in the habit of the bodie , makes that more vehement concussion , which they call a rigor . either of which doth so long endure , as till the atoms of heat , being more strong by concentration and union , have re-encountered and expelled them . that it is of the nature of hot atoms , when invaded by a greater number of cold ones , to recoyle from them , and concentre themselves in the middle of the body , that contains them ; is demonstrable from the experiment of frozen wines : wherein the spirits concentre , and preserve themselves free from congelation in the middle of the frozen phlegm , so that they may be seen to remain fluid and of the colour of an amethyst : as helmont hath well declared , in his history of the nativity of tartar in wines . ( . ) that the death of all animals , is caused immediately by the atoms of cold ; which insinuating themselves in great swarms into the body , and not expelled again from thence by the overpowered atoms of heat ; they wholly impede and suppress those motions of them , wherein vitality consisteth : so that the calorifick ones being no longer able to calefy the principal seat of life , the vital flame is soon extinguished , and the whole body resigned to the tyranny of cold. which is therefore well accounted to be the grand and profest enemy of life . chap. xiii . of fluidity , stability , humidity , siccity . sect . i. here our very method must be somewhat paradoxical , and the genealogy we shall afford of those two vulgarly accounted passive ●●ualities , humidity and siccity , very much different from that universally embraced in the schools . for , should we tread in the steps of aristotle , as most , who have travelled in this subject , have constantly done ; we must have subnected our disquisition into the nature and origine of moisture and dryness , immediately to that of heat and cold , as the other pair of first elemental qualities , and ●diametro opposite to them . but , having observed , that those terms , moist and dr● ▪ are not , according to the severe and praecise dialect of truth , rightly ●●commodable to all those things , which are genuinely imported by 〈◊〉 greek words , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 and 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , according to the definions of aristotle ▪ and consequently that we could not avoid the danger of losing ●●●selves in a perpetual aequivocation of terms , unless we committed ou● thoughts wholly to the conduct of nature herself , progressing from the more to the less general qualities , and at each step explicating their distinct dependencies : we thereupon inferred , that we ought to praem●se the consideration of fluidity and firmness , which are more gener●●● to that of humidity and siccity , as less general qualities , and 〈◊〉 seem to be one degree more removed from catholick principles . that those 〈◊〉 terms so frequent in the mouth of aristotle , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ▪ 〈…〉 in signification , than humidum and siccum , by which his 〈◊〉 interpreters and commentators commonly explicate them ; 〈…〉 even from hence , that under the word 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 is comprehended no● only , in general , whatever is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , fluid and liquid , but also , in special , that matter or body , whereby a thing is moistned , when immersed into , or perfused with the same : and likewise , under the contrary term 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , is comprehended as well , in general , whatever is 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , compact or firm and solid , as in special , that matter or body , which being applyed to a thing , is not capable of humectating or madefying the same , and which is therefore called also 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , aridum . now this duely perpended doth at first sight detest the aequivocation of the latin terms , and direct us to this praecise determination ; that whatever is fluid , is not humid ; nor whatever is dry , compact or firme ; but that a humid body properly is that , whereby another body , being perfused , is moistned [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] or madefied [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] : and , on the contrary , that a dry or arid body is that , which is not capable of humectating , or madefying another body , to which it is applied . again , forasmuch as aristotle positively defines 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , id qu●d facile , terminum admittens , proprio tamen non terminatur , that which being destitute of self-termination , is yet easily terminated by another substance ; t is evident , that this his definition is competent not only to a humid thing , in special , but also to a fluid , in general : such as are not only water , oyle , every liquor , yea and metal or other concretion , actually fused or melted ; but also the aer , flame , smoke , dust , and whatever is of such a nature , as that being admitted into any vessel or other continent of whatever figure ; or however terminated in it superfice , doth easily accomodate it self thereunto , put on the same figure , and confess termination by the same limits or boundaries ; and this , because it cannot terminate it self , as being naturally comparated only to diffusion . on the other side , since he defines 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , quod facile terminatum proptio termino , terminatur aegre alieno ; to be that which is easily terminate● by its owne superfice , and hardly terminated by another ; it is also manifest , that this definition is not peculiar only to a dry or ●rid substance , but in common also to a firme or solid one : such as not only earth , wood , stones , &c. but also ice , metal unmolten , pitch , resine , wax , and the like concreted juices , and ( in a word ) all bodies , which have their parts so consistent and mutually cohaerent , as that they are not naturally comparated to diffusion , but conserve themselves in their own superfice , and require compression , dilatation , section , detrition , or some other violent means , to accommodate them to termination , by the superfice of another body . and , certainly , if what is praecisely signified by the terme 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , were no more than what is meant by the latin substitute thereof , humidum : then might the aer be justly said to be humid , which is so far in its owne nature from being endowed with the faculty of humectating bodies , that its genuine virtue is to exsiccate all things suspended therein ; nay even fire it self might be allowed the same attribute , together with smoke , dust , and the like fluid substances , which exsiccate all bodies perfused with mo●sture . on the advers part , if what is praecisely intended by the terme 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , were fully expressible by the latin , siccum , or aridum ; then , doubtless , might wax , re●ine , and all concreted juices be accounted actually dry ▪ nay ice it self , which is only liquor congealed , could not be excluded the categorie of arid substances . these considerations premised , though we might here enquire , whether aristotle spake like himself , when he confined fluidity ( and that according to his owne definition ) to only elements , water and aer ; when yet the element of fire , which he placed above the aer●●l region , must be transcendently fluid ( else how could it be so easily terminated by the concave of the lunar sphere , on one part , and the convex of the aereal , on the other ? ) and whether his antithesis or counter assertion , viz. that the firme elements are fire and earth , be not a downright absurdity : yet shall we not insist upon the detection of either of those two errors , because they are obvious to every mans notice ; but only conclude , that though every humid body be fluid , and every arid or dry body be firm ; yet will not the conversion hold , since every fluid is not humid , nor every firme , dry ; and upon natural consequence , that humidity is a species of fluidity , and siccity a species of firmity ; and also that it is our duety to speculate the reasons of each accordingly beginning at the generals . fluidity we conceive to be a quality , arising meerly from hence ; that the atoms ▪ or insensible particles , of which a fluid concretion doth consist , are smooth in superfice , and reciprocally contiguous in some points , though disso●●●●● or incontiguous in others ; so that many inane spaces ( smaller and grea●●● according to the several magnitudes of the particles , which intercept them being interspersed among them , they are , upon the motion of the mass o● body , which they compose , most easily moveable , rowling one upon ●●other , and in a continued fluor , or stream diffusing themselves , till th●● are arrested by some firm body , to whose superfice they exactly accommodate themselves . that the ●●sence of fluidity dont consist only in these two conditions , the smoothness of insensible particles , and interruption of small inane spaces among them ▪ where their extrems are incontiguous ; may be even sensibly demonst●●●●d in an heap or measure of corne. which is apt for diffusion , or fluid , only because the grains , of which it doth consist , are superficially smooth and hard , and have myriads of inane spaces intercepted among them ▪ by reason of the incontiguities of their extrems , in various points : so 〈◊〉 ▪ whenever the heap is moved , or effused from one vessel into anothe● ▪ the grains mutually rowling each upon other , diffuse themselves in one continued stream , and immediately upon their reception into the concave of the vessel , the aggregate or mass of them becomes exactly accommo●●te to the figure , or internal superfice of the same . and , forasmuch as the ●ifferent magnitudes of composing particles , do not necessitate a differe●●e of formal qualities ; but only variety of figures , contexture and 〈◊〉 : well may we conceive the same reasons to essence the fluidity of water also ; because betwixt an heap of corne , and an heap or mass of water , the difference is only this , that the grains , which compose the one , are of sensible magnitude , and so have sensible empty spaces interposed amo●● them ; but the granules , or particles , which compose the other , are 〈◊〉 sensible magnitude , or incomparably more exile , and so have the inane 〈◊〉 intercepted among them , incomparably less . for , that water doth consist of small grains , or smooth particles , is conspicuous even from 〈◊〉 ▪ that water is capable of conversion into fume , or vapou● ▪ only 〈◊〉 ●●refaction , and fume again reducible into water , meerly by 〈◊〉 ; and the reason why fume becoms visible , is only this , that the 〈…〉 part of fume is a collection or assembly of many thousand of tho●●●●●gly-invisible particles , which constitute the water , from whence the ●●me ascends , as may be ascertained from hence , that to the composition of one single drop of water , many myriads of myriads of insensible particles must be convened and united . so that water contained in a caldron , set on the fire and seething , doth differ from the fume exhaled from it , only in this respect ; that the one is water condensed , the other rarified : or , that water is made fume , when its particles are violently dissociated , and the aer variously intercepted among them ; and fume is returned to water , when the same particles are reduced to their natural close order , and the intercepted aer again excluded . again , that the fluidity of water depends on the same cause ( proportionately ) as that of an heap of corne , may , according to the lawe of similitude , be justified by the parallel capacity of water to the same effects , viz. diffusion , division , and accommodation to the figure of the recipient , or terminant : for , the result hereof is , that it hath no continuity or mutual cohaerence of its particles , which should hinder their easy dissociation . nor is it a valid argument to the contrary , that water appears to be a continued body , but an heap of corne , a discontinued ; for , that is only according to apparence , caused from hence , that by how much smaller the component particles of a concretion are , by so much smaller must the inane spaces be , which are intercepted among them , where they are incontiguous , and upon consequence , so much the less interrupted , or more continued must the mass or aggregate appear : as may be most familiarly understood , if we compare an heap of corne , with one of the finest callis sand ; that with an heap of the most volatile or impalpable powder , that the chymist or apothecary can make ; and so gradually less and less in the dimensions of granules , till we arrive at the smallest imaginable . so that we cannot wonder , that the substance of water should be apprehended by the dull sense , as wholly continued , though really it be only less interrupted than an heap of sand : when the grains , whereof water is amassed , are incomparably smaller , than those of the finest sand , and intercept among them inane spaces incomparably smaller such as are by many degrees belowe the discernment of the acutest sight , though advantaged by the best microscope . if this argument reach not the height either of the difficulty it self , or your expectation and curiosity concerning it ; be pleased to imp the wings of it with the feathers of another , of the same importance , but more perspicuity . it is well known , especially to chymists and refiners , that every metall is capable of a twofold fluid●ty : one , in the forme of an impalpable or volatile powder ; the other , of a liquor , whose fluor is continued , according to the judgement of sense . for , when a metal is calcined by praecipitation , i. e. by corrosive and mercurial waters , specifically appropriate to its nature ; being thereby reduced into small grains , it becomes fluid , after the manner of sand , and therefore may as conveniently be used in hour-glasses , for chronometry , or the measure of time : but , because each of those visible grains is made up of millions of other more exile and invisible granules or particles , which are the component principles or matter of the metal ; hence it is , that if we put them all together in a crucible , and melt them in a reverberatory fire , whose igneous atoms invade , penetrate and subdivide each granule into the smallest particles ( to which the corrosive virtue of the aqua fortis could not extend ) then will the whole mass put on another kind of fluidity , such as that of water , oyle , and all other liquors ▪ now , the reason of the former fluidity is manifestly the same with that of corne and sand , newly explicated : and that of the latter ▪ the same as of water , i. e. the granules of the calcined powder , being dissolved into others of dimensions incomparably smaller , do intercept among themselves , or betwixt their superficies , where those a●e incontiguous , innumerable multitudes of inane spaces , but those incomparably less than before their ultimate subtiliation ; and consequently ( as hath been said ) make the metal dissolved to be deprehended by the sen●● ▪ as one entire and continued substance . to conclude , therefore ; 〈…〉 discover no reason against us , of bulk sufficient to obstruct the 〈◊〉 o● our conception , that the fluidity of fire , flame , aer , and all ●●quid substances whatever , cannot well be deduced from any other 〈◊〉 , but what we have here assigned to water and metals dissolved : 〈◊〉 when we consider , that is equally consentaneous to conceive , th●●●●ery other fluid or liquid body is composed also of certain specially ●●●●igurate granules ▪ or imperceptible particles ; which being only 〈◊〉 in some points of their superficies ▪ not reciprocally cohaerent 〈…〉 intercept various inane spaces betwixt them ▪ and be therefore easily 〈◊〉 , dissociable , externally termin●ble , and capable of making the body app●●●ntly continuate , as water it sel● . and , as 〈…〉 other general quality , firmness , or stability ; since 〈◊〉 m●st have contrary causes , and that the solidity of atoms is the 〈◊〉 of all solidity and firmness in concretions : well may we understand 〈◊〉 be radicated in this , that the insensible particles , of which a ●irme 〈◊〉 is composed ( whether they be of one or diverse sorts , i. e. 〈◊〉 or dissimilar in magnitude and figure ) do so reciprocally comp●●● and adhaere unto each other , as that being uncapable of rowling 〈◊〉 each others superfice , both in respect of the ineptitude of 〈◊〉 figures thereunto , and the want of competent inane spaces among them ▪ they generally become uncapable 〈◊〉 without extream 〈◊〉 of emotion , dissociation , diffusion , and so of terminatio● 〈◊〉 any other superfice , but what themselves constitute . if it 〈…〉 enquired , whence this reciprocal comp●ession , indissociability . 〈◊〉 immobility of insensible particles in a firme , concretion doth 〈◊〉 proceed ▪ we can derive it from three sufficient causes . ( . the 〈◊〉 small [ hamul● , uncinulive ] hooks or clawes by which atoms of 〈…〉 superficies are adapted to implicate each other , by mutual 〈◊〉 and that so closely , as that all inanity is excluded from betwixt 〈◊〉 ●●mmissures or joynings ; and this is the principal and most frequent 〈◊〉 of stability . ( . ) the introduction and pressure of extran●ou● 〈◊〉 ▪ which invading a concretion , and wedging in both themselves , 〈…〉 intestine ones together , and that cheifly by obverting the● 〈…〉 or superficies thereunto ; cause a general compression and 〈…〉 of all the particles of the mass . and by this way doth 〈…〉 water and all humid substances ; for , since the atoms of 〈…〉 , and those of water octahedrical , as is most 〈…〉 ; those of cold insinuating themselves into the 〈…〉 by obversion of their plane sides to them , they 〈…〉 particle● thereof , and so not permitting them to be 〈…〉 fluidity , and make the whole mass rigid and 〈…〉 hither also may we most congruously referr the coagulation of milk , upon the injection of rennet , vinegre , juice of limons , and the like acid things . for , the hamous and inviscating atoms , whereof the acid is mostly composed , meeting with the ramous and grosser particles of the milk , which constitute the caseous and butyrous parts thereof ; instantly fasten upon them with their hooks , connect them , and so impeding their fluiditie ▪ change their lax and moveable contexture into a close and immoveable or firme : while the more exile and smooth particles of the milk , whereof the serum or whey is composed , escape those entanglings and conserve their native fluidity . this may be confirmed from hence ; that whenever the cheese , or butter made of the coagulation , is held to the fire , they recover their former fluidity : because the tenacious particles of the acid are disentangled and interrupted by the sphaerical and superlatively agile atoms of fire . ( . ) the exclusion of introduced atoms , such as by their exility , roundness and motion , did , during their admistion , interturbe the mutual cohaesion and quiet of domestique ones , which compose a concretion . thus , in the decalescence of melted metals , and glass , when the atoms of fire , which had dissociated the particles thereof and made them fluid , do abandon the metal , and so cease to agitate and dissociate the particles thereof : then do the domestique atoms returne to a closer order , mutually implicate each other , and so make the whole mass compact and firme , as before . thus also when the atoms of water , wine , or any other dissolvent , which had insinuated into the body of salt , alume , nitre , or other concretion retaining to the same tribe ; and dissolving the continuity of its particles , metamorphosed it from a solid into a fluid body , so that the sight apprehends it to be one simple and uniforme substance with the liquor : we say , when these dissociating atoms are evaporated by heat , the particles of the salt instantly fall together again , become readunated , and so make up the mass compact and solid , as before , such as no man , but an eye-witness of the experiment , could persuade himself to have been so lately diffused , concorporated , and lost in the fluid body of water . sect . ii. by the light of the praemises , it appears a most perspicuous truth , that humidity is only a certain species of fluidity . for , whoever would frame to himself a proper and adaequate notion of an hum●r , or humid substance ; must conceive it to be such a fluid or fluxile body , which being induced upon , or applied unto any thing , that is compact , doth adhare to the same ( per minimas particulas ) and madify or humectate so much thereof as it toucheth . such , therefore , is water , such is wine , such ●s oyle , such are all those liquors , which no sooner touch any body not fluid , but either they leave many of their particles adhaerent only to the superfice thereof ( and this , because the most seemingly polite superfice is full of eminences and cavities , as we have frequently asserted ) and so moisten it ; or , penetrating through the whole contexture thereof , totally humectate or wett the same . but , such is not aer , such is not any metal fused , such is not quick-silver , nor any of those fluors , which ●hough they be applied unto , and subingress into the pores of a compact body doe yet leave none of their particles adhaerent to either the superficia● 〈◊〉 internal parts thereof ; but , without diminut●●n of their own quantity 〈◊〉 off clearly , and so leave the touched o● pervaded body , unma●ified , 〈◊〉 ●●humecta●e , as they found it . on the other side , it is likewise manifest , that siccity o● aridity , is only a certain species of firmness , or st●bility : because a dry or 〈◊〉 ●ubstance is conceived to be firm or compact , only insomuch as it is 〈◊〉 of all moisture . of this sort , according to vulgar conception , may 〈◊〉 account all stones , sand , ashes ▪ all metals , and whatever is of so firme a constitution ▪ as contain● nothing of humidity , either in it superfice , 〈…〉 , which can be extracted from it , or , i● extracted , is not capable 〈◊〉 moistning any other body : but , not plants nor animals , nor minerals ▪ 〈◊〉 any other concretion● which ▪ though apparently dry to the sense doth 〈◊〉 cont●in some moisture within it , and such as being educed , is capable of 〈◊〉 another body . we say ▪ ●ccording to vulgar conception ; because , not absolutely : for ▪ though 〈◊〉 be opposed to humidity , not as an habit , to which any act can 〈…〉 attributed , but as a meer privation ( for , to be dry , is nothing else 〈…〉 want moisture yet , because a moistned body may contain more 〈…〉 humidity ▪ therefore may it be said to be more or less dry 〈◊〉 , and a body that is imbued with less moisture , be said to be dry 〈…〉 one imbued with more . thus green wood , or such as hath 〈◊〉 extraneous moisture , is commonly said to grow more and more 〈…〉 degrees , as it is more and more dehumect●ted ; and then at leng●● 〈◊〉 be perfectly dry , when all the aqueous moisture , as well natura● 〈◊〉 ●mbibed , is consumed , though then also it contain a certain 〈◊〉 mo●sture , which philosophers call the humidum primigentum 〈◊〉 ▪ this only comparatively , or in respect to its forme● 〈…〉 was imbue● with a greater proportion of humidity ▪ for the 〈◊〉 of this , we are to observe , that there are two sorts 〈…〉 compact bodies are usually humectated ; the one , 〈…〉 ●he other , oleag nous and fat. the first is easily 〈…〉 by heat , but not inflammable : the other , though it 〈…〉 and is as easily inflammable in regard of the many 〈…〉 is not easily exsoluble , nor attenuable into 〈…〉 cohaerence of its particles . to the first 〈…〉 that m●●sture in concretions ▪ which chymists extracting 〈…〉 vegetables : because , though it mo●stens as wate● 〈…〉 incapable of infl●mmation ▪ yet is it much more volatile 〈…〉 and to e●ther or both sorts , though in a diverse respect belong 〈…〉 they call aqua vitae , or the spirits of a vegetable , such 〈…〉 because though it doth moisten as water , yet is 〈…〉 evaporable by heat , and as inflammable as 〈…〉 learn in the school of sense , that such bodie● 〈…〉 aqueous and lean moisture , are easily 〈…〉 are humectate with the unctuous 〈…〉 hardly ▪ why ? because the atoms , of which the aqueous doth consist , are more laevigated or smooth in their superfice , and so having no hooks , or clawes , whereby to cohaere among themselves , or adhaere to the concretion , are soon disgregated ; but those , which compose the oleaginous , being entangled as well among themselves , as with the particles of the body , to which they are admixt , by their hamous angles , are not to be expeded and disengaged , without great and long agitation ; and after many unsuccessfull attempts of evolution . thus wood is sooner reduced to ashes , than a stone : because that is compacted by much of aqueous humidity ; this by much of unctuous . for the same reason is it likewise , that a clodd of earth , or peice of cloth , which hath imbibed water , is far more easily resiccated , than that earth or cloth , which hath been dippt in oyle , or melted fat . and this gives us somewhat more than a meer hint toward the clear solution of two problems , frequently occurring , but rarely examined . the one is , why pure or simple water cannot wash out spots of oyle , or fat from a cloth , or silk garment : which yet water , wherein ashes have been boyled , or soap dissolved , easily doth ? for , the cause hereof most probably is this ; that though water of it self cannot penetrate the unctuous body of oyle , nor dissociate its tenaciously cohaerent particles , and consequently not incorporate the oyle to it self , so as to carry it off in its fluid arms , when it is expressed or wrung out from the cloth : yet , when it is impraegnated with salt , such as is abundantly contained in ashes , and from them extracted in decoction ; the salt with the sharp angles and points of its insensible particles , penetrating , pervading , cutting and dividing the oyle , in minimas particulas , the water following the particles of salt at the heels , incorporates the oyle into it self , and so being wrung out from the cloth again , brings the same wholly off together with it self . which d●ubtless ▪ was in some part understood by the inventor of soap ; which being compounded 〈◊〉 water , salt and oyle most perfectly commixt , is the most general abstersive for the cleansing of cloathes polluted with oyle , grease , turpentine , sweat and the like unctuous natures : for , the particle● of oyle ambuscadoed in the soap , encountring those oyly or p●nguous particle● , which adhaere to the hairs and filaments of cloth and st●●n it , become easily united to them , and bring them off together with themselves , when they are dissolved and set afloat in the water by the incisive and di●●●ciating particles of the salt ; which also is brought off at the same time by the water , which serveth only as a common vehicle to a●l the rest . the other , why stains of ink are not delible , with water , though decocted to a lixirium , or lee , with ashes , or commixt with soap : but wi●● 〈◊〉 acid juice ▪ such as of limons , oranges , crabbs , vinegre , &c. 〈◊〉 reason hereof seems to be only this ; that the vi●●io● or 〈◊〉 which ●tr●kes the black in the decoction of galls , sumach , or other 〈◊〉 ingredients , being acid , and so consisting of particles congener●●s ●n figure and other proprieties to those which constitute the 〈…〉 : whenever the spot of ink is throughly moystned with an acid 〈◊〉 , the vitrio●●s soon united thereto , and so educed together with ●t up●n expression , the union arising ( propter 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) from the similitude of their two natures . for , there always is the most easy and perfect union , where is a similitude of essences , or formal proprieties ; as is notably experimented in the eduction of cold from a mans hands or other benummed parts by rubbing them with snow ; in the evocation of fire by fire ; in the extraction of some venoms from the central to the outward parts of the body , by the application of other venoms to the skin ( which is the principal cause , why some poysons are the antidotes to others ) ; the alliciency and ●●●●uation of choler by rhubarb , &c. lastly , in 〈◊〉 place , we might pertinently insist upon the causes and manner of co●●osion and dissolution of metals and other compact and firm● bodies ▪ 〈◊〉 aqua fortis , aqua regis , and other chymical waters ; the 〈◊〉 of salt , alume , nitre , vitriol , sugar and other salin concreted 〈◊〉 by water ▪ the exhalability or evaporability of humid and 〈◊〉 substances ▪ and other useful speculations of the like obscure natur● but 〈◊〉 of these deserves a more exact and prolix disquisition , than the 〈…〉 signed to our praesent province will afford ; and what we have already 〈◊〉 sufficiently discharge●h our debt to the title of this chapter . chap. xiv . softness , hardness , flexility , tractility , ductility , &c. sect . i. the two first of this rank , of secun●darie qualities hardness and softness , be●ng so neer of extraction and semblance , that m●ny have confounded them with firmness and fluid●ty ▪ in a general and looser accept●tion ( for● so virgil gives the epithe●e of soft to water , & lucretius to aer , vapor● clouds , &c. because a firme bodie , or such whose parts are reciproc●lly cohaerent , and superfice more 〈…〉 apparently continued , as 〈◊〉 may be soft ; and on the other side , a fluid body , or such whose 〈…〉 not reciprocally cohaerent , nor 〈◊〉 really continued , as 〈…〉 be hard : therefore ought we 〈…〉 examination ●f the nature of hardness and softness , 〈…〉 consequents , flexility , tractility , 〈◊〉 , &c. where that of ●●●mness and 〈◊〉 ends ▪ that so we may ▪ by explicating their cognation , when men●●one● in a general sense , manifest the●r differences ▪ when considered in a special and praecise , and so prevent the otherwise imminent danger of aequivocat●on . to come , therefore , without farther circumambage ▪ to the discuisition of the proper nature of each of these qualities , according to the method of their production ; conforming our conceptions to those of aristotle , who ● . meteor . . ) defines durum to be ▪ quod ex superficie in seipsum non ●edit ; and molle , to be quod ex superficie in seipsum cedit ; and referring both to the cognizance of the sense of touching , we understand a hard body to be such ▪ who●e par●icles are so firmely coadunated among themselves , and superfi●e is so con●inued , ●s that being prest by the finger ▪ it doth not yeeld thereto ▪ nor ha●● 〈◊〉 ●uperfice at all indented or depressed thereby ; such ●s a stone ▪ and on the con●rary , a soft one to be such , as doth yield to the pressure of the finger in the superfice , and that by retrocession or giving back of the superficial particles , immediately prest by the finger , versus profundum , towards it profound or internal ; such as wax , the flesh of animals , clay , &c. for , the chief difference betwixt a fluid , and a soft body , accepted in a philosophical or praecise , not a poetical or random sense , consisteth only in this ; that the fluid , when prest upon , doth yield to the body pressing , not by indentment or incavation of it superfice , i. e. the retrocession of it superficial particles , which are immediately urged by the depriment , toward its middle or profound ones , which are farther from it ; but by rising upwards in round and equally on all sides , as much as it is deprest in the superfice : and a soft doth yield to the body pressing , only by retrocession of it superficial inwards toward it central particles , so that they remain during , and sometimes long after the depression , more or less lower than any other part of the superfice . which being considered , aristotles judgement , that softness is incompetent to water , must be indisputable : because t is evident to sense , that water , being deprest in the superfice doth not recede towards its interior or profound parts , as is the property of all soft things to doe ; but riseth up in round equally on all sides of the body pressing , and so keeps it superfice equally and level as before . as for the fundamental cause of hardness observed in concretions ; it must be the chief essential propriety of atoms solidity : and upon consequence , the original of its contrary , softness must be inanity . for , among concretions , every one is more and more hard , or less and less soft , according as it more and more approacheth to the solidity of an atom , which knowes nothing of softness : and on the other side , every thing is more and more soft , or less and less hard , according as it more and more approacheth the nature of inanity , which knowes nothing of hardness . not that the inane space is therefore capable of the attribute of soft , as if it had a superfice , and such as could recede inwards upon pression : but , that every concretion is alwayes so much the more soft , i. e. the less hard , by how the more it yields in the superfice upon pressure ; and this only in respect of the more of inanity , or the inane space intercepted among the solid particles , whereof it is composed . it need not be accounted repetition , that we here resume what we have formerly entrusted to the memomory of our reader ; viz. that touching the deduction of these two qualities ▪ hardness and softness , the provident atomist hath wonn the garland from all other sects of philosophers : for , supposing the catholike materials of nature to be atoms , i. e. solid or inflexible and exsoluble bodies , he is ●urnished with a most sufficient , nay a necessary reason , not only for the hardness or inflexibility , but also for the softness or flexibility of all concretions ; insomuch as it is of the essence o● his hypothesis , that every compound nature derives its hardness only from the ●olidity of its materials , and softness only from the inane space intercepted amon● its component particles ; in respect whereof each of those particles is moveable , and so the whole aggregate or mass of them becomes flexible , or devoid of rigidity in all its parts , and consequently yeelding in that part , which is pressed . but , no other hypothesis excogitable is fruitful enough to afford a satisfactory , nay not so much as a meerly plausible solution of this eminent and fundamental difficulty ; for , those who assume the universal matter to be voyd of hardness , and so infinitely exsoluble , i. e. not to be atoms , though they may , indeed , assign a sufficient reason , why some concretions are soft ; yet shall they ever want one to answer him , who demands , why other concretions are hard ; because themselves have exempted atoms , from whose solidity all hardness ariseth to concretions . and this most easily detecteth the gross and unpardonable incogitancy of aristotle , when he determined the hardness and softness of concretions to be absolute qualities ; for , since atoms alone are absolutely void of all softness , and the inane space alone absolutely void of all hardness ; and all concretions are made up of atoms : nothing is more manifest , than that hardness and softness , as attributary to concretions , are qualities meerly comparative , or more praecisely , that softness is a degree of hardness ; and consequently , that there are various degrees of hardness , according to which concretions may be said to be more or less hard , and such as are hard , in respect of one , may be yet soft in respect of another , that is more hard , or less soft . as for the praecise manner , how the several degrees of hardness and softness result from atoms and inanity commixt ; we need not much insist thereupon ; since the production of each degree may be easily and fully comprehended , from our praecedent explanation of the causes of fluidity and firmness . for , though softness be observable in bodies endowed with firmness , or influxibility ; yet because the degrees of firmness are also various , and proceed from the more or less arresting or impeding of fluidity , and so that the thing consist of atoms more or less coarctated , moveable among themselves , and dissociable each from other ( from whence alone doth the yeeldingness of it in the superfice arise ) : therefore is it necessary , that in firme things the same is the cause of softness , which in fluid things is the cause of fluidity . nor is the difference betwixt their productions other than this , that to softness , specially and strictly accepted , are required atoms somewhat hooked , and so retentive each of other , as not to be wholly dissociated , or to permit a manifest abruption or breach of continuity , upon pressure : but , to strict fluidity it is not requisite , that the atoms be at all hamous , or reciprocally retentive . insomuch , therefore , as there is some certain compactness ( more or less ) even in all soft concretions ; from thence it may be easily inferred , that the general reason of the mollification of hard bodies , doth consist in this ; that their insensible particles be in some degree dissociated , i. e. so separated each from other , in many points , as that more and larger inane spaces be intercepted among them , than while they were closely coadunated : and on the contrary , that the general reason of the induration of soft bodies , doth consist only in this ; that their insensible particles , before in some degree dissociated , be reduced to a closer order , or higher degree of compactness , and so most of the inane spaces intercepted , be excluded from among them . to this the doubting mersennus fully subscribes ( in lib. . harmonicor . proposit . ultima ) where deducing the causes of hardness , rigidity , and the like qualities from the atoms of democritus and epicurus , he plainly saith ; duritiem fieri ab atomis ramosis , quae suis hamatis implicationibus perexigua spatia relinquunt inania , per quae nequeant ingredi corpuscula caloris , &c. nay , such is the urgencie of this truth , that aristotle himself seems to confess it , in these words : quae humoris absentia concrescunt & duruntur , ea liquefacere humor potest ; nisi adeo sese ( particulae nimirum ) collegerint coierintque , ut minora partibus aquae foramina sint relicta : id quod fictili accidit , &c. ( . meteorum . cap. . ) and we need seek no farther than a ball of wool , for the exemplification of both ; for , that being so relaxed , as that the hairs touch each other more rarely , or in fewer points , and thereupon more of the ambient aer be intercepted among them , instantly becomes soft : and then being so compressed , that the hairs touch each other more frequently , or in more points , and the aer be thereupon again excluded from among them , it as soon becomes hard . but if we wind up our curiosity one note higher , and enquire the special manner of mollifying hard bodies ; we shall find it to rest upon either heat , or moisture . upon heat , when the atoms of fire , subingressing into the pores of a hard concretion doe so commove and exagitate the insensible particles thereof , that they become incontiguous in more points , than before , and so the whole mass being made more lax and rare , upon the interception of many new inane spaces among its particles , puts on a capacity of yeelding to any thing that presseth it , and of receding from it superfice toward its interiors , according to the property of softness . thus iron made red hot , is mollefied , and hard wax liquefied by heat . upon moisture , when the particles of an humor so insinuate themselves among the closely cohaerent particles of a hard body , that dissociating them in some measure , they intermix among them , and so ( themselves being sufficiently yeelding upon pressure ) cause the bodie to become yeelding and recessive from it superfice inwards . thus leather is softned by lying in water , or oyle ; and clay assumes so much the more of softness , by how much the more of water it hath imbibed . on the other side , if we pursue the induration of soft bodies up to its special manner , we shall secure it either in cold , or siccity . in cold , whether we understand it to be a simple expulsion of calorifick atoms , lately contained in the bodie ; as in the growing hard of metals after fusion : or the introduction of frigorifick atoms into the bodie , naturally void of them ; as in the induration of water into ice . in siccity , whether we conceive it to be a meer expulsion of the particles of moisture from a concretion ; as when earth is baked into bricks : or a superinduction of drie particles upon a moist concretion ; as in the composition of pills , which for the most part consist of drie powders and syrupe , or some other viscid moisture . but here we feel a strong remora , or doubt ; how it comes about , that iron made glowing hot , and immediately plunged into cold water , acquires a greater degree of hardness , than it had before ? and to remove it , we answer ; that the particles of the water subingress into the amplified pores of the iron , and are not again excluded from thence , though the particles thereof returne to their former close order , and reciprocally implicate each other , as before in candescence ; but , remaining imprisoned in the small incontiguities , or inane spaces , which otherwise would have been empty , make the body of the iron somewhat more solid or hard than otherwise it would have been . that this is a sufficient cause of that effect , may be warrantably inferred from hence ; that if the sam● seasoned iron be afterwards brought to the fire again , and therein made red hot , so that the contexture of its particles be relaxed , and the particles of water , which possess the inane spaces betwixt them , be evaporated ; there doth it resume its former softness ; and this our smiths call nealing of iron . to steer on , therefore , the same course of disquisition we have begun ; forasmuch as softness is defined by the facility , and hardness by the difficulty of bodies yielding in the superfice : the only considerable remaining to our full explanation of the formal reason of each of these two qualities , is , how the yielding of a soft body in the superfice is effected ; for , that being once explicated , the rule of contraries will easily teach us , wherein the resistence of a hard doth immediately consist . and th●s requires no taedious indagation , for from the praemises it may easily be collected ; that a soft body doth then yeild , when its particles immediately pressed in the superfice , do sink down and subingress into the pores immediately beneath them , and then press down the next subjacent particles into pores immediately beneath them ; and those likewise press down the next inferior rank of particles into void spaces below them ; an those again press down others successively until ( the number of pores or void spaces successively in each subingression decreasing ) there be no more room to receive the last pressed particles , and then the subingression ceaseth . if this seem not sufficient to make the yeildingness of soft bodies clearly intelligible ; we must remit our reader to our praecedent discourse concerning the incapacity of aer to be condensed or compressed , in a wind-gun , beyond a certain proportion , or determinate rate . farther , because a soft body cannot be squeezed , unless it rest upon or against something that is hard , at least , less soft than it selfe ; so that , though the lower superfice thereof , relying upon the support , is so bounded , that it hath no liberty of space , whether to recede versùs profundum ; yet hath it full liberty of space versus latera : therefore comes it to pass , that the subingression of particles into pores , and the compression of others , is made not only versus profundum , in that part of the soft body , which directly confronteth the hard , whereupon it resteth ; but also versus latera , toward the sides , or circumambient . and that after a various manner , according to the various contextures of soft bodies in the superfice . for , if the superfice ( i. e. the outward part ) of a soft body , be of a more compact and tenacious contexture , than the interior mass or substance ; as is the skin of an animal , compared to the subjacent flesh , and a bladder in respect of the oyle therein contained : in that case , the compression of the particles is , indeed , propagated by succession to some distance as well toward the bottom , as the sides , to which the superior particles being pressed directly downward , and there resisted , deflect ; yet not to that distance , as where the superfice is of the same contexture with the interior mass , as in wax and clay , in both which , the compression , and so the yeilding may be propagated quite thorow , or from the superior to the inferior superfice , where it immediately resteth upon the hard body , all the intermediate particles starting toward the sides , as being pressed above and resisted belowe . and hereupon , doubtless , was it that aristotle properly called those soft bodies , whose superfice is either of a weaker , or of the same contexture with their internal substance , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , formatilia ; insomuch as when a seal or other solid body doth press them , they suffer such a diffraction or solution of continuity in their superficial parts , as that the dissociated particles are not able to restore themselves to their former situation and mutual cohaesion , but retain the figure of the body which pressed them : and , on the contrary , such as have the contexture of their superfice more firm and tenacious than that of their internal mass , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , pressilia ; insomuch as upon pressure they suffer not so great a diffraction or solution of continuity in their superficial parts , but that they still have some mutual cohaerence , and so are able to restore themselves to their former situation , upon the remove of the body that pressed them . for the illustration of this , it is observable ( ) that to the yielding of every soft body , when pressed , it is necessary , that it have freedom of space on its sides : because , if the lateral particles , when pressed by the intermedia●● ones , have not room whether to recede , they cannot yield at all ; and so the compression must be very small . this may most sensibly be exemplified in a tube filled with water ; for , if you attempt to compress the water therein contained , with a r●mmer so exactly adapted to the bore of the tube , as that no spaces be left betwixt it and the sides thereof , whereat the water may rise upward , you shall make bu● a very small and almost insensible progress therein . ( ) that no superfice of what contexture soever , can be depressed versus profundum , or be any way dilated , but it must suffer some diffraction or solution of continuity ; more or less . for , insomuch as each particle of the superfice doth possess a peculiar part of space proportionate to its dimensions ; and though upon the dilatation of the superfice , i. e. the remove of its particles to a more lax order , greater spaces are intercepted among them , yet are not the particles multiplied in number , nor magnified in dimensions , and so cannot possess more or greater spaces than before : therefore is it necessary , that the superfice be variously crackt , and the continuity thereof infringed in many places . the necessity hereof doth farther evidence it self in the flexion of a twig , cane , or other [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] flexile body ; for , when a twigg is bended , as the concave superfice becomes contracted and corrugated , the particles thereof being not able to penetrate each other , nor crowd themselves into fewer places : so at the same time , is the convex dilated , and suffers many small breaches or cracks , the particles thereof being uncapable either to multiply themselves , or possess more spaces , than before . the same likewise is easily intelligible in a tractile body , such as ( aristotle names 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) a nerve , or lutestring : for allbeit the interruption of continuity be not so manifest to the sense in a tractile as in a flexile body : yet may we observe , that when a tractile body is extended or drawn out in length , it is extenuated or diminished in thickness . and , what , think you , becomes of those interior particles , which compose its crassitude or thickness ? certainly , they must come sorth into the superfice , that so they may interpose themselves ●mong the dissociated particles thereof , possess the void spaces left betwixt them , and with their small clawes or hooks on each hand cohaering to them , make the superfice apparently continued . would you observe the interruption of continuity among the superficial particles of a tractile body , and the issuing forth and intermistion of interior particles among them ; be pleased to paint over a lutestring with some oyled colour , and afterward vernish it over with oyle of turpentine : then strain it hard upon the lute , and you shall plainly perceive the superfice of it to crack and become full of small clefts or chinks , and new particles ( not tincted with the colour ) to issue forth from the entralls of the string , and interpose themselves among those small breaches . lastly , the same is also discoverable by the sight in a ductile body [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] such as every metal ; for , no metal , when pressed or hammerd , is dilated or expanded on all sides , for any other reason but this , that it is as much attenuated in thickness , and the particles in the superfice are so dissociated , as that the interior particles rise up , possess the deserted spaces , and cohaere to the discontinued exterior particles , as may be more plainly discerned if the superfice of the metal be tincted with some colour . sect . ii. from the praemises , whereupon we therefore insisted somewhat the longer , ●t is manifest , that flexility , tractility , ductility , and other qualities of the same classis , are all the consequents of softness : as the contrary to them all rigidity , is the consequent of hardness ; insomuch as whoever would frame to himself an exact notion of a rigid body , meerly as a rigid , must compose it of the attributes , inflexile , intractile , inductile . nor doth any thing remain to our clear understanding of the nature of flexility , but the solution of that great difficulty , cur flexilia , postquam inflexa fuerint , in pristinum statum resiliant ? why a flexile body , such as a bowe of wood , steel , whalebone , &c. doth , after flexion , spring back again into its natural figure and situation ? the reason of this faculty of restitution , we conceive ( with the immortal gassendus ) to be this ; that the recurse or resilition of a flexile body is a certain reflex motion , which is continued with a direct motion : as we shall have opportunity professedly to demonstrate , in our subsequent enquiry into the nature of motion . in the mean while , it may suffice to stay the stomach of curiosity , that we evidence the cause of it to be the same with that of the rebound of a ball , impelled by a racket , from a wall : for , as the force , which makes the ball rebound from the wall , is the very same which first impelled it against the wall ; so is the force , which reflecteth a bowe , after bending , the very same which bended it . to exemplifie ; when a man layes a staff transversly upon a beam , and strikes the end that is toward him , downward ; the end that is from him , must rise , as much upward : as well because of the resistence of the beam ( which here performs the office of an hypomochlion , or middle fulciment ) as of the continuity and compactness of the staff it self ; and so the same cause , the hand of the man , which impelled the one extreme of the staff downward , is also the cause of the rising of its other extreme upward . again , let the staff have liberty of play between two beams , the one above , the other beneath it ; and upon the depulsion of one end , the other shall rise up , and be impinged against the upper beam , and from thence rebound back again upon the lower , and thence again to the higher , and thence again to the lower , and so alternately be reflected from one to the other , till the force of resistence in the beams hath wholly overcome that of the first percussion or impulse : yet still doth the last rebound , no less than the first , owe it self to the same cause , which impressed the first motion upon the staff , which was the hand of the man , who impelled it . to approach one degree neerer ; set up a staff perpendicularly in some hole in the floore or pavement , so that it may have some liberty of motion to each hand : and then , if you impel or inflect the upper extreme to the right hand , the part of the lower extreme , which respecteth the upper part of the right side of the hole , will press upon the same , and the other side of the lower extream , where it toucheth the lowest part of the left side of the hole , shall be at the same time impinged likewise against the left side ; and that so forcibly , that it shall rebound from thence to the opposite side , and at the same time , the upper part , which you inflected , ●hall rebound from the right to the left : and thus shall the staff be agitated from side to side , by alternate resilitions , till the resistence of the hole h●●h wholly overcome the force thereupon imprest , by your hand . this laid down , we infer , that the cause of returne in the staff , is the same with that of the self-restorative motion in bodies flexile ; for , that you may be able to inflect one end of the staff , it is necessary , that some part of it be held fast in your hand , some hole , chink , or other hold , that so you may distinguish the hypomochlion , or point of rest , from the part inflected . nor is it ought available to the contrary , to object ( ) that the staff is not bent with one single stroke , but a continent pression : because a continent pression is nought else but a continent repetition of strokes ; and that is the last stroke , immediately upon which the last and non-impeded reflexion doth ensue . . that our example of the resilition of a staff is incongruous , there being a considerable rigidity therein , but none in flexile bodies : for , though there be no perfect or absolute rigidity in flexile substances , yet is there a sufficient firmness , which is a degree of rigidity ; and by how much greater that is , by so much the greater force of impulse is required to the inflexion , and consequently so much stronger is the reflection . so that while the bottome of the staff , and its hypomochlion alternately performe their offices , the one reflecting this , the other the contrary way , so many more alternate reflexions , or excurses and recurses are made , by how much greater the rigidity of the staff , and firme fixation in its hold , are ▪ and 〈◊〉 contra . and , since the reflection , which is made from the firmely fix● part , is as it were the fundamental , or general reflexion ; innumerable special or particular reflexions , exactly like the general , are made in singulis partibus ▪ insomuch as the parts of the concave superfice are so compressed , in order , one after another , from the deflected extrem to the fixt , that suffering mutual resistence , they are compelled to start back in the same order , one after another ; and the parts of the convex superfice , from the fixt extreme to the deflected , are so retracted in order one after another , that they return in order to their natural site ; and some parts thus conspiring with others , reduce the whole inflected bodie to its natural situation and figure . finally , because every reflex motion is alwaies ( though , perhaps , not sensibly ) weaker , than the direct ; therefore is it , that in every deflexion , both to the concave superfice , some particles subingress to the interiors of the flexile bodie , which cannot returne forth again to the superfice ; and to the convex , other particles egress to the superfice , which cannot returne in again to the interiors : whereupon it comes to pass , that by how much the longer the inflexion is continued , or how much the more frequently repeated ; by so much the more contracted is the concave superfice made , and so continues , and so much more deduced or dilated is the convex superfice made , and so continues ; and consequently both the inflexion and reduction become as so much the weaker , so as much the smaller . nay , where the deflexion is so great , as that some parts of either superfice are wholly diffracted and dissociated , and so can no longer maintain that mutual cohaerence and continuity , which is necessary to the series of reflexion and retraction : there doth no reduction at all followe , after inflexion , at most only so much , as is made by the parts , which yet remain cohaerent , in which also we must allowe the distinction of concavity and convexity . thus , when a twigg is broken half off in the middle , by overmuch bending ; it makes no more reflexion , than what depends only upon the half which is unbroken . as for tractility likewise , all the obscurity which remains upon its nature , depends upon this difficulty ; cur nervus distentus , & è suo situ distractus toties hinc inde redeat ? why doth a tractile bodie , such as a nerve or lutestring , when distended , and abduced from the line of direction to either side , not only reduce it self from that obliquity to directness ; but recurr beyond it , and then returns toward the place of its first abduction , and thence back again to and beyond the line of direction , and so makes many excurses and recurses ? and this may be soon solved , by answering ; that the cause of this tremulation or vibrations of a tractile thing , distended and percussed , or abduced , seems to be the same with that of the reflexion of a flexile , newly rendred . for ( . ) a chord distended , is nothing but a flexile body ; and so much the more apt for reflection , by how much more it is distended : because tension is a kind of rigidity . ( . ) a chord distended hath the reason not only of one simple flexile bodie , but also of two conjoyned ; insomuch as it hath extrems , in each of which we may distinguish the hypomochlion , or fixt part , from the reflectent ; and in the middle , or that part , which is percussed or abduced by the plectrum or finger , there are as it were other extremes conjoyned , which being naturally reluctant each to other , cause the reciprocal reduction each of other . ( . ) as a twigg , after inflexion , doth 〈◊〉 beyond the middle , or line of directness , and goes and comes frequently , till it hath overcome the fist impressed motion , and recovered its natural site because after the first reflexion is made , a second succeeds , for the same reason , as the first , a third for the same reason as the second , and so a fourth , fifth &c. successively : so also , is it necessary , that many vibrations , or excurses and recur●es be alternately made , by a chord dist●nded and percusled ; becau●e the s●●e cause r●mains to the second , third , fourth , &c. which was to the fi●st . lege me●sennum , harmonicor . lib. . propos. . corollario de atomis . but here comes the problem ( such a one as put even mersennus himselfe to the eruditis physicomathematicis discutiendum relinquo ; harmonicor . lib. . proposit . . ) and that is ; cur diadromus chordae maximus eodem tempore conficit totum spacium , quo minimus , aut reliqui singuli diadromi intermedii illud conficiant ? whence is it , that all the excurses and recurses , or diadroms of a chord , either vertically , or horizontally distended , and abduced from the line of direction ; are isochronical , or aequitemporaneous , though not aequispacial : as also are all the vibrations of a flexile body , fixt at one extream , and deflected at the other . this stupendious phaenomenon may be thus demonstrated . let f. g. ( in the second diagram ) be the chord horizontally distended ; which , being distracted from its direct situation , f. g. to a. makes its several diadroms , a.b. b.c. c.e. and e.d. now we say , that all these diadroms , though greatly disproportionate in point of space , are yet exactly proportionate in point of time , i. e. the first diadrom , a. b. doth measure its whole space , in the same proportion of time , as doth the second diadrom , b. c. or the third , c. e. or the fourth e. d. ▪ for , since the violence or impetus , whereby the chord is abduced from the line f. g. to the point a. is so much the greater , by how much the longer the line of the epidrom is , the chord must pervade it space so much the more speedily , by how much the space is greater , compared to that of the subsequent ones : it necessarily followes , that all the subsequent diadroms must be aequidiurnal , because look how much is detracted from the longitude , magnitude , and impetus of the subsequent diadroms exactly so much accedeth to the brevity of the space , which they are to percurr ; and so the longitude of the posterior epidrom becomes inverted in proportion to the time , and its brevity of space compensateth the decay of that impetus , which was in the prior diadrom . for example ; let the chord , which makes an hundred diadroms , perv●de a foot space , in its first diadrom , and the hundredth part of a foot , at its last , or hundredth diadrom : we affirm , that the first diadrom must be an hundred times swifter than the last ; which is an hundred times slower , as being to the same proportion less violent , and that which immediately praecedeth the quiet of the cord , in the direct line , f. g. more plainly ; the first diadrom , a. b. as it is the greatest , so is it the most violent ; and as it is the most violent , so must the velocity , whereby it pervades the whole space betwixt a.b. be also the greatest : and the second diadrom , b. c. how much it comes short , in violence of tension , and celerity of motion , of the first , so much doth it come short of the magnitude also thereof ; so that though the space of the former , a. b. be much larger than that of the second , b.c. yet doe they both pervade their several spaces in the same proportion of time , because , as the second diadrom , b. c. hath less of violence and of celerity , than the first , a. b. so hath it just so much less of space to pervade , and so the diminution of space compensateth the diminution of violence and celerity . wherefore , the reason of the third diadrom being the same to the second , as that of the second to the first ; and of the fourth to the third , as that of the third to the second : it is manifest and necessary , that all the diadroms be● aequidiurnal , though not aequispatial ; which is what we assumed . but yet the lees of the problem remain behind ; for it is worthy farther enquiry : why a chord of a duple length , v.g. of foot , doth performe its diadroms in a duple proportion of time , to a chord of a single length , v. g. of foot ; when both are distended by equal force , or weight : and yet , if the chord of foot be distended by doubly as great a force or weight as that of only foot , it doth not performe its diadroms with velocity duple thereunto ; but only if the force of its distension be quadruple to the force first supposed ? and to exhaust them , though somewhat rough and crabbed , we answer , as in a pensile bodie , or chord vertically distended by a weight , the time of each single excurse , is equal to that time , in which the same weight would , if permitted , be falling from such an altitude , as is commeasurable by the diametre of the circle , whereof arches are described by the excurses of the pensile body abduced from the perpendicular : so in a tensile body , such as a chord strained upon a lute , all the times , in which a part of the chord accepted exactly in the middle , excurreth from one side , are equal to one time , in which one of its extrems , if cut off , would directly pervade the whole length , and come into the place of the other , toward which the force , being still the same behind , would draw it . for , the same force , certainly , is alwaies able to produce the same effect : and if the lateral spaces of the diadroms doe continually decrease ; the velocity of the motion must also continually decrease . and the cause of that continual decrement , can be no other but the force drawing or distending the chord , which continually refracteth the contrary force , by the plectrum or finger impressed thereupon . now , since all the excurses of a chord , of whatever length , are exaequated to one and the same direct trajection thereof , as we said even now ; in the former case , the trajection cannot but be performed in a duple proportion of time , as a duple proportion of space is assumed to be trajected or pervaded , by the same motive or attractive force : but in the latter not , because three equal things being supposed , viz. time , space , and the weight or attractive force , it is of pure necessity , that the same space remaining , look how much of time is diminished , so much is the motive force encreased , and what is the proportion of space to time , the same is the proportion of the motive force to space . and hence comes it , that the proportion of space to time being as that of to ; the motive force must have to space the proportion of to : and consequently to time , not as to , but as to . lastly , as for ductility , little remains additional to what we have formerly said , concerning the formal reason thereof , but the solution of that notable problem , about the admirably vast extensibility of that king not only of metals , but of the whole earth , gold. and , indeed , since we have it upon the testimony of our experience , that one ounce of pure gold may be , by malleation , extended to such an amplitude , as to cover ten acres of land ; and that one grain thereof may be wier drawne into a thread of such incomparable fineness , as to commensurate foot ; and consequently , that one ounce of gold is capable of deduction into a thread , whose length may fufill the measure of two hundred and thirty thousand , and four hundred feet , of six inches apiece : we say , this being avouched by those mechaniques , who deale in beating of gold into leaves , and drawing it out into wier , it seems well worthy our enquiry , upon what cause this stupendious praerogative of gold doth chiefly depend . in a word , therefore , we conceive this superlative extensibility of gold , to be warrantably referrible to a threefold cause , viz. the unparalleld compactness of it substance , the great tenuity of its component particles , and the multitude of small hooks or clawes , whereby those particles reciprocally implicate each other , and maintain the continuity of the whole mass. for ( ) the exceeding compactness of its contexture doth afford parts sufficient to so great extension , i. e. such an abundance of them , as upon the decrement of the mass in profundity , may rise up into the superfice and enlarge the latitude , or longitude : ( ) the tenuity of its component particles maketh the mass capable of diminution in profundity , and so of augmentation in superfice , even to an incredible proportion : and ( ) the multitude of small hooks , whereby those exile particles reciprocally cohaere , sufficeth to the constant continuity ; for , while the mass is suffering under the hammer , no sooner can the stroke thereof dissociate one particle from its neighbour , but instantly it layes hold of and fastneth upon another , and as firmely cohaereth thereunto , as to its former hold : so that the mutual cohaesion is maintained even above the highest degree of extension or attenuation , which any imaginable art can promise . nay , so sufficient a cause of incredible ductility doth this last seem to be , that mersennus regarded no other : as may be collected from these his words : sunt autem corpora maximè ductilia , quae habent atomos undique hamatas , ut aurum ; cujus atomi non ita possunt evolui , ut sese deserant in inferioribus , aut superioribus partibus , quin laterales succedant , quibus usque ad insignem tenuitatem perveniant ; ( harmon . lib. . propos . . corollario de atomis . ) this apprehended , the chymist needs not longer to perplex himself about the cause of the incorruptibility , and incapacity of volatilization in gold : and if his so promising art can attain to the investment of any metal with these proprieties ; let other men dispute , whether it be gold or no , for our parts , we oblige our selves so to accept it . now , that we may run through all other secondary qualities , in this one course , we farther observe ; that to the praedominion of softness , men ought to refer sectility , such as is seen in wood cut transversly : and fissility , such as in wood cleft along the grain . for , whateve is [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] sectile , must in some sort return to the nature of flexility ; seeing that the parts of it , which are immediately pressed upon by the edge of the axe , knife , or other cutting instrument , must recede inwardly , i. e. from the superfice to the profundity of the mass , and the lateral parts , at the same time , give back on each hand , for otherwise there could be no yeilding , and so no cutting ; and in like manner , whatever is [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] fissille , must have so much of flexility also , as that , when the parts of it , in the place , upon which the force is first discharged , begin to be dissociated , a certain compression must run along successively to all the other parts , which are afterwards to be dissociated . but , though a fission , or cleaving may be made without any deperdition of substance , or excession of parts from the body cleft ; those parts , which were coadunated sec. longitudinem , being only separated sec. longitudinem : yet is that impossible in any section whatever , though made by the acutest edge imaginable ; because , look how much of the body doth commensurate the bredth of the edge of the cutting instrument , so much , at least , is beaten off and destracted from the body , betwixt the sides of the incision . and thus much concerning the consequents of softness . as for those of hardness ; they are tractility and friability . for , whatever is [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] fractile , capable of fraction into pieces , as a flint and most other stones , must have so much of rigidity , ( the chief propriety of hardness ) as may suffice to hinder the yeilding of it superfice , upon pressure or percussion ; and consequently all subingression of superior particles into the small vacuities intercepted among the inferior ones ; and so to cause , that the superfice is first diffracted , and successively all the subjacent particles dissociated , quite thorow to the contrary superfice , the inferior particles being still pulsed by the superior [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] by reason of their continuity . so that the fragments into which the body is shattered , are greater or less , either according to the diverse contexture thereof in divers parts , in respect whereof some parts may be contexed more compactly and firmely , and others again more laxly and weakly : or according to situation , in respect whereof those parts , which are neerer to the circumference , she off more easily than those , which are more remote . in like manner , whatever is properly [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] friabile , brittle , as marble , glass , earthern vessels , &c. must also have so much of rigidity , as to make it uncapable of flexion , traction , diduction , or extension , by any means whatever : so that upon any forcible pression , or percussion , the whole mass or substance of it is shivered into dust , or broken into greater fragments , which are easily subject to be crumbled into dust afterward . now , that a hard or rigid bodie being percussed , or pressed , with force sufficient , in one extreme or superfice , the percussion or pressure may be propagated from part to part successively , till it arrive at and be determined in the other extreme ; may be evinced by sundry most 〈◊〉 experiments , some whereof are recited by the lord st. alban ( in ●●lva sylvarum cent. . ) but this one will serve the turne . when an oyster , or tortois shell is let fall from a sufficient altitude , upon a stone , 〈◊〉 is usually shattered into many peices ; and that for no other reason but this , that the lower side , whether convex or concave , being vehemently impinged against the stone , the particles thereof immediately knockt by the stone , as vehemently give back , and in their quick retrocession impell the particles situate immediately above them ; whereupon those impelled particles with the same violence impell others next in order above them , until the percussion being propagated from part to part successively quite home to the upper superfice , it comes to pass , that each percussed part giving back , the whole shell is shattered into small fragments . all which may seem but a genuine paraphrase upon the text of mersennus . ( harmonicor . lib . propos . . ) duritiei verò proprietas appellatur rigiditas ; quae fit ab atomis ita sibi invicem cohaerentibus , ut deflexionem impediant : quod contingit in corporibus , quae constant atomis cubicis , octuedris & tetruedis , ex quibus resultat perfecta superficiecularum inter se cohaesio ; hinc ●it ut rigida corpora fructilia sint , non autem sectilia , & ictu impacto tota in frusta dissiliant . qui adum praedictae superficiunculae se invicem premunt , quae sunt ex una parte , dimoventur ab iis , quae ex alia ; adeo ut unico impetu externo corpori impresso , contusio sentiatur per totum , & partium eodem , momento fit separatio . there yet remains a quality , which is the ofspring neither of softness alone , nor hardness alone ; but ought to be referred partly to the one , partly to the other : and that is ruptility . for , not only such bodies , as challenge the attribute of softness , are subject to ruption , when they are distressed beyond the tenour of their contexture , either by too much inflexion , as a bow over bent ; or too much distention , as leather or parchment over strained ; or too much malleation , as a plate of lead , iron , or other metal over hammerd : but such also as claim the title of hardness , and that in an eminent proportion , as marble ; for , a pillar of marble , if long and slender , and laid transversly or horizontally , so as to rest only upon its two extrems , is easily broken asunder by its own weight . for , as soft bodies , when rackt or deduced beyond the r●te of mutual cohaerence among their parts , must yeeld to the external force , which distres●eth them , and so suffer total discontinuity : so hard ones , when the internal force , or their owne weight , is too great to be resisted by their compactness , as in the example of a long marble pillar , not supported in the middle ; then must they likewise yeeld to that superior force , and break asunder . and here the archer and musician , put in , for a solution of that problem , which so frequently troubles them ; viz. cur chordae facili●●s circa ex●rema , quam circa medium frangantur , cum vi vel pondere , sive horizontaliter , sive verticaliter trahuntur ? why bowstrings , lutestrings , and other chords , though of uniforme contexture throughout , and equally distended in all parts , do yet usually break asunder , not in the middle , or neer it , but at one end , where they are fastned ? the cause , certainly , must be this ; that the weight or drawing force doth alwayes first act upon the parts of the string , which are neerest to it , and successively upon those , which are farthest off , i. e. in the middle : so that the string suffering the greatest stress neer the extrems , is more subject to break there , than in any other part . wherefore , whenever a bowstring breaks in or neer the middle ; it may safely be concluded , that the string was weakest in that place . to which we may add this also , that experienced archers , to praevent the frequent breaking of their strings , and the danger of breaking the bow thereby ; injoyn their string-makers , to add a link of flax , or twist more at the ends of each string , than in any other parts of it : and that they call the forcing , because experience hath taught them , that the force of the bow is most violently discharged upon those parts of the string , which are neerest to the horns . chap. xv. occult qualities made manifest . sect . i. having thus long entertained it self with the most probable reasons of the several wayes and means , whereby compound bodies exhibite their several attributes and proprieties to the judicature of the sensitive faculties in animals , and principally in man , the rule , perfection and grand exemplar of all the rest ; t is high time for our curiosity to turn a new leaf , and sedulously address it self to the speculation of another order , or classis of qualities , such as are vulgarly distinguished from all those , which have hitherto been the subject of our disquisitions , by the unhappy and discouraging epithite , occult . wherein we use the scarce perfect dialect of the schools ; who too boldly praesuming , that all those qualities of concretions , which belong to the jurisdiction of the senses , are dependent upon known causes , and deprehended by known faculties , have therefore termed them manifest : and as incircumspectly concluding , that all those proprieties of bodies , which fall not under the cognizance of either of the senses , are derived from obscure and undiscoverable causes , and perceived by unknown faculties ; have accordingly determined them to be immanifest or occult. not that we dare be guilty of such unpardonable vanity and arrogance , as not most willingly to confess , that to ourselves all the operations of nature are meer secrets ; that in all her ample catalogue of qualities , we have not met with so much as one , which is not really immanifest and abstruse , when we convert our thoughts either upon its genuine and proxime causes , or upon the reason and manner of its perception by that sense , whose proper object it is : and consequently , that as the sensibility of a thing doth noe way praesuppose its intelligibility , but that many things , which are most obvious and open to the sense , as to their effects , may yet be remote and in the dark to the understanding , as to their causes : so on the contrary , doth not the insensibility of a thing necessitate , nay , nor aggravate the unintelligibility thereof , but that many things , which are above the sphere of the senses , may yet be as much within the reach of our reason , as the most sensible whatever . which being praecogitated , as , when we look back upon our praecedent discourses , touching the originals and perception of sensible qualities , we have just ground to fear , that they have not attained the happy shoar of verity , but remain upon the wide and fluctuating ocean of meer verisimility : so also , when we look forward upon our immediately subsequent disquisitions into the causes of many insensible qualities , are we not destitute of good reason to hope , that though we herein attempt the consignation of consentaneous and probable causes to sundry of those effects , which schollars commonly content themselves only to admire , and without farther exercise of their intellectuals , to leave wrapt up in the chaos of sympathies and antipathies ; yet will not the ingenious misunderstand us , or conceive that we esteem or propose those reasons as oraculous or apodicticall , or create an expectation of the discovery of such originals , whereupon those rarer operations and magnalia of nature do proximely and genuinely depend . however , some may think it expedient for us to profess , that as in our former enquiries , so in this , our designe is only to explain sundry admired effects , by such reasons , as may appear not altogether remote and incongruous , but consentaneous and affine to truth ; that so no mans judgement may be impeached by embracing them for most probable , untill the ( in that respect , too slow ) wheel of time shall have brought up some more worthy explorator , who shall wholly withdrawe that thick curtain of obscurity , which yet hangs betwixt natures laboratory and us , and enrich the commonweal of letters , by the discovery of the real verity and this we must enterprize , by continuing our progress in the allmost obliterated tract , that epicurus and democritus so long since chalk'd forth ; not by treading in the beaten road of aristotle and his se●tators , who ( for ought we have learned ) were they , who first founded that ill contrived sanctuary of ignorance , called occult qualities . for , generally setting up their rest in the commistion of elements , and their supposed immateriall qualities ; and being not able ever to explicate any insensible propriety , from those narrow and barren principles : they thought it a sufficient salvo for their ignorance , simply to affirme all such proprieties to be occult ; and without due reflection upon the invalidity of their fundamentals , they blushed not to charge nature herself with too much closeness and obscurity , in that point , as if she intended that all qualities , that are insensible , should also be inexplicable . the ingenious sanchez , among many sceptical arguments of the uncertainty of sciences , seasonably urgeth this one , as very considerable , against physiologists ; that when any natural problem , such as that of the attraction of iron by a loadstone , of straws by amber , &c. is objected to them ; instead of setting their curiosity on work to to investigate the causes thereof , they lay it in a deep sleep , with that infatuating opium of ignote qualities : and yet expect that men should believe them to know all that is to be known , and to have spoken like oracles cencerning that theorem ; though at the same instant , they do as much as confess , that indeed they know nothing at all of its nature and causes . for , what difference is there , whether we say , that such a thing is occult ; or that we know nothing of it ? nor is it a course either less dishonorable to the professors , or dangerous to the students of philosophy , to refer such effects , upon which men commonly look with the eye only of wonder , to secret sympathies and antipathies : forasmuch as those windy terms are no less a refuge for the idle and ignorant , than that of occult proprieties , it being the very same in importance , whether we have recourse to the one , or to the other . for , no sooner doe we betake ourselves to either , but we openly confess , that , all our learning is at a stand , and our reason wholly vanquisht , and beaten out of the field by the difficulty proposed . we deny not , that most , if not all of those admired effects of nature , which even the gravest heads have too long thought sufficient excuses of their despair of cognition , do arise from some sympathy , or antipathy betwixt the agent and patient : but yet for all that , have we no reason to concede , that nature doth institute or cause that sympathy or antipathy , or the effect resulting from either , by any other lawes , or means , but what she hath ordained and constantly useth , to the production of all other common and familiar effects . we acknowlddge also , that sympathy is a certain consent , and antipathy a certain dissent betwixt two natures , from one , or both of which there usually ariseth some such effect , as may seem to deserve our limited admiration : but is it therefore reasonable for us to infer , that those natures are not subject unto , nor regulated by the general and ordinary rules of action and passion , whereto nature hath fitmely obliged herself in the rest of her operations ? to lance and cleanse this cacoethical ulcer , to the bottom , consider we , that the general laws of nature , whereby she produceth all effects , by the action of one and passion of another thing , as may be collected from sundry of our praecedent discertations , are these : ( . ) that every effect must have its cause ; ( ) that no cause can act but by motion ; ( ) that nothing can act upon a distant subject , or upon such whereunto it is not actually praesent , either by it self , or by some instrument , and that either conjunct , or transmitted ; and consequently , that no body can move another , but by contact mediate , or immediate , i. e. by the mediation of some continued organ , and that a corporeal one too , or by it self alone . which considered , it will be very hard not to allowe it necessary , that when two things are said either to attract and embrace one the other by mutual sympathy , or to repell and avoid one the other , by mutual antipathy ; this is performed by the same wayes and means , whereby we observe one body to attract and hold fast another , or one body to repell and avoid conjunction with another , in all sensible and mechanique operations . this small difference only allowed , that in gross and mechanique operations , the attraction , or repulsion is performed by sensible instruments : but , in those finer performances of nature , called sympathies and antipathies , the attraction or repulsion is made by subtle and insensible . the means used in every common and sensible attraction and complection of one bodie by another , every man observes to be hooks , lines , or some such intermediate instrument continued from the attrahent to the attracted ; and in every repulsion or disjunction of one bodie from another , there is used some pole , lever , or other organ intercedent , or somewhat exploded or discharged from the impellent to the impulsed . why therefore should we not conceive , that in every curious and insensible attraction of one bodie by another , nature makes use of certain slender hooks , lines , chains , or the like intercedent instruments , continued from the attrahent to the attracted , and likewise that in every secret repulsion or sejunction , she useth certain small goads , poles , levers , or the like protruding instruments , continued from the repellent to the repulsed bodie ? because , albeit those her instruments be invisible and imperceptible ; yet are we not therefore to conclude , that there are none such at all . we every day behold spiders letting themselves down from high roofs , and as nimbly winding themselves up again at pleasure , by such slender threads of their own occasionall and extemporary spinning , as t is not every common eye that can discern them . nay , in a mask at court , we have seen a whole chorus of gods descend into the theatre , as from the clouds , only by wires and other lines , so fine and slender , as that all the light of the tapers burning therein was not sufficient to discover them to the sight of the spectators : and vast and ponderous scenes so suddenly and dextrously shifted , by the almost inobservable motions of skrews , elevators , pulleys , and the like archimedean engines and devices , that the common beholders , judging only by the apparence , or ( rather ) non-apparence , have thought those great machines to have been automatous , or to have moved themselves , and at last to vanish into nothing . and shall we not then allowe the incomparably more curious mechaniques of natures , the exemplar of art , to be wrought by instruments of subtility incomparably greater : and that many of those small engines , whereby she usually moves and susteins bodies of considerable bulk and weight , are corporeal , though by incomputable excesses below the perception of our acutest sense ? certainly , for us to affirm , that nothing material is emitted from the loadstone to iron , which by continuity may attract it ; only because our sense doth deprehend nothing intercedent betwixt them : is an argument of equal weight with that of the blind man , who denied the being of light and colours , because he could perceive none . in a word , if there be any validity in what we have so plainly asserted , and frequently inculcated , touching the hebetude or grossness of our senses , on one part , and the great exility of all aporraea's or effuxes streaming from bodies , on the other ; and if tha● oracle , reason , be to be heard , which so long since persuaded hippocrates , and many other , secretaries of nature , that most , if not all bodies are [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] perspirable and conspirable , i. e. that they continually emit insensible effluvia's from themselves to others : we say , if there be any weight in all this , men cannot think it unreasonable in us to conceive , that those admired effects , which they commonly ascribe to hidden sympathies and antipathies , are brought about by the same ways and means , which nature and art use in the causation of the like ordinary and sensible effects ; and that the instruments of natural attraction , complectence , repulsion , sejunction , are corporeal , and hold a neer analogie to those of artificial ; only these are gross and perceptible , those subtile and imperceptible . notwithstanding the perspicuity of these arguments , we shall not supererogate , to heighten the lustre of so desirable a truth , by the vernish of a convenient and praegnant simile , or two . if we attentively observe a chamaeleon catching gnats and other small flyes in the aer , for his food ; we shall see him dart out a long and slender tongue , with a small recurvation at the tip , and birdlimed with a certain tenacious and inviscating moisture , wherewith , in a trice , laying hold of a fly , at some distance from his mouth , he conveys the same into it with such cleanly speed , as exceeds the legerdemane of our cunningst juglers , and may have been the cheif occasion of that popular error , that he lives meerly upon aer . and when we see a peice of amber , jet , hard wax , or other electrique , after sufficient friction , to attract straws , shavings of wood , quils , and other festucous bodies of the same lightness , objected within the orbe of their alliciency ; and that with a cleanly and quick motion : why should we not conceive , that this electricity or attraction may hold a very neer analogy to that attraction of gnats , by the exserted and nimbly retracted tongue of a chamaeleon . for ( ) it is not improbable , that the attraction of all electriques is performed by the mediation of swarms of subtle emanations , or continued rayes of exile particles , comparative to so many chamaeleons tongues ; which through the whole sphere of their virtue , in various points mutually intersecting , or decussating , and more especially toward their extreams , doe not only insinuate themselves into the pores of those small and light festucous bodies occurrent , but lay hold upon several insensible asperities in their superfices , and then returning ( by way of retraction ) back to their original or source , bring them along in their twined arms , and so long hold them fast in their complicate embraces , as the warmth and radial diffusion , excited by affriction , lasteth . ( ) all the disparity , that can be objected , seems to consist onely in the manner of their return , or retraction ; the tongue of the chamaeleon being both darted forth , and retracted by help of certain muscles , wherewith nature , by a peculiar providence , hath accommodated that otherwise helpless animal : but , electriques are destitute of any such organs , either for the exsertion , or reduction of their rayes . and this is not so great , but it may be solved , by supposing , that as if the chamaeleons tongue were drawn forth at length by a mans hand , and not extruded by the instruments of voluntary motion , it would again contract and reduce it self spontaneously , after the same manner as nerves and lutestrings retract and curle up themselves , after violent distension : so may the rayes , which stream from an electrique , being abduced from their fountains , not spontaneously , but by the force of praecedent affriction , be conceived to reduce and retract themselves , after the manner of sinews and lutestrings violently extended . ( ) that such tenacious rayes are abduced from amber and other electriques , is easily convincible ( besides the experiment of their attraction of convenient objects ) from hence ; that all electriques are unc●uous and pinguous concretions , and that in no mean degree : and manifest it is , that a viscid and unctuous bodie is no sooner warmed by rubbing , but there rise out of it certain small lines or threads , which adhaere to a mans finger that toucheth it , and such as may , by gentle abduction of the finger , be prolonged to considerable distance . but , however this may be controverted , and the way of all electrique attractions variously explicated , according to the various conceptions of men ; the itch of phancy being soonest allayed by the liberty of ones singular conjecture , in such curious theorems : yet still is it firme and indubitable , that though the attraction of straws by amber , be in some sort admirable , yet is it not miraculous , as is implied in that opinion , which would have it to be by some immaterial ( i e. supernatural ) virtue ; and that it is effected by some corporeal , though both impalpable and invisible organs continued from the attrahent to the attracted . on the other side , as for the abaction , or repulsion of one thing by another , in respect whereunto vulgar philosophers have thought and taught , that the abacted or repulsed doth ( if an animal ) voluntarily ( if inanimate ) spontaneously flie from and avoid conjunction with the abacting , or repellent , by reason of some hidden enmity or antipathy betwixt their forms : though the reasons and manner of such fugation , so far forth as concerns animals , may be collected from our former discourses of the gratefulness and offensiveness of sensible objects ; yet shall we here f●rther illustrate the same by certain analogies and similitudes . when a nettle is objected to a mans hand , why doth he withdraw it from the same ? not upon the account of any antipathy in his hand to the nettle ; because being bruised , or withered , no childe but will boldly handle it : but , because the nettle is pallizado'd with millions of small stings , or prickles , which like so many darts , wounding the the skin , cause a pain therein , and so the man , for avoidance of harm , catcheth his hand from it , as an injurious object . why likewise doth the nose abominate and avoid stinking odours , whenever they are brought neer it ? is it not because such foelid and offensive odours consist , for the most part , of such sharp and pungent particles , as holding no correspondence to the pores and contexture of the odoratory nerves , are no sooner admitted , but they in a manner scratch , wound and dilacerate the sensory ? and may we not conceive those disproportionate particles of the ungrateful odour to be as so many small lances or darts , which offer the same injury to the mammillary processes of the brain , that the prickles of a nettle offer to the skin ? certainly , as the nettle strikes its darts into the skin , and not into the nayles of a mans hand ; because those are of too close and firm a contexture to admit them : so doth an offensive odour immit its painted and angular particles into the tender smelling nerves , and not into the skin , because its contexture is more compact , than to be capable of puncture or dilaceration thereby . lastly , why doth the eye abhor and turne from ugly and odious objects ? is it not only because the visible species emitted from such bodies , doth consist of particles of such configurations and contexture , as carry no proportion to the particles and contexture of the optique nerves , but striking upon the retina tunica , instantly wound and exasperate the slender and tender filaments thereof , and so cause the eye , for fear of farther injury , to close , or avert it self ? and are not those acute and disproportionate particles , composing the visible species , worthily resemblable to so many small prickles or lancets , which though too subtile to wound the skin , nostrils , or other parts of the body , whose composure is less delicate , do yet instantly mis-affect and pain the optique nerves , whose singular contexture doth appropriate to them the capacity of being sensible of that compunction ? now , putting all these considerations into the scale together , and ponderating them with an equal hand ; we shall find their weight amount to no less than this : that as every sympathy is displayd by certain corporeal , though invisible organs , comparated to attraction and amplectence ; so is every antipathy , by the like invisible organs , comparated to repulsion and sejunction ; which is what we assumed . hence may we , without much difficulty , extract more than a conjectural judgement , what are the first and general causes of all love and hatred . for , look what kind of motions , whether grateful or ungrateful , are by the species impressed upon the nerves peculiarly inservient to that sense , by which the object is apprehended ; the very same are continued quite home to the brain , and therein accordingly move and affect the common sensory : so as that , according to the pleasure or offence of the perception , there is instantly excited an affection either of prosecution of the thing , by whose species that pleasant motion was caused , and that is the hint and ground of loving and desiring it ; or of aversation from it , and that is the ground of hating and declining it . nay , the same may be well admitted also for the cause , why things a like in their natures , love and delight in the society each of other ; and on the contrary , why unlike natures abhor and avoid each other . for , as those which are consimilar in their temperaments , affect each other with congenerous and grateful emanations : so doe those of dissimilar mis-affect each other with discordant and ungrateful . and therefore it is no longer a wonder , that men love , or dislike each other commonly at first interview , though they scarce know why : nor can we longer withold our assent to that unmarkable opinion of plato , that similitude of temperaments and so of inclinations , is not only the cement , but basis also of amity and friendship . sect . ii. from this general disquisition into the reasons of all sympathy , and ant●pat●y , to 〈◊〉 most of those proprieties , which by ph●losophers are 〈◊〉 as stupendious and abscon●ite , are u●u●lly referred ; we must ●●vance to the consideration of part●cular inst●n●es , that by the solution of singula●s , we may afford the gre●ter 〈◊〉 to mens curi●sity , and ●●ve so many oppo●tunities of examining t●e verisimility of our former thesis , that all such effects , the knowledge of w●ose causes is generally 〈◊〉 of , are produced by sub●●a●tial and explicable means . an● in order her●unto , we shall , according to the method of the no less 〈◊〉 than judicious ●racastorius ( de sympath . & antipath . rerum ) distin●u●sh all occult ●ualities into general , and special ; subdividing the generall into ( ) the conspiration of the parts ●f the universe , and ( ) the i●flux of caelestial upon sublunary bodies : and the speciall into such as concern ( ) inanimates , ( ) insensibles , ( ) sensibles . to the first general order , viz. the conspiration and harmony of all parts of the universe , philosophers unanimously adscribe the avoidance of vacuity ; whereupon many are the secrets , that are presumed to ensue , as the ascention of heavy , descent of light bodies , the sejunction of congenerous and sociable natures , the conjunction and union o●●iscordant and unsociable , and the like irregular and praeposterous effects . but , as for all these secrets , we have long since declared them to be no secrets but the most ordinary and manifest operations of nature . ●or , in our ex●mination and solution of all the apparences in the late 〈◊〉 experiment of introducing a vacuum in a tube , by water or quick-silver , invented by torri●●ius ; we have at large proved , that nature ●●th not abhor any but sensible , or coacervate emptiness : nor that neither 〈◊〉 , or upon the necessity of an absolute plenitude of all places ●n the ●niverse ; but by accident only , and that either in respect of the natural confluxibility of the parts of fluid bodies , such as aer and water , which causeth them with great velocity to flow into the parts of space ●e●erted by a body passing thorow them ; or of the repugnancie of admitting tw● bodies into one and the same place , at the same time , their solidity prohibiting the penetration of ones dimensions by the other . wherefore , 〈◊〉 no man henceforth account the conspiration of the parts of the universe , to be an occult quality ; or so much stand amazed at all or any of th●●e phaenomena , which arise from natures aversion from vacuity 〈◊〉 as if they had some extraordinary lawes and constitutions particularly o●dained for their production , and belonged to some higher oeconomy th●n that , according to which she regulates her common active and passive principles . to the second , viz. the influx of caelestial upon sublunary bodies , innumerable are the effects , which the fraud of some , the admiration of many , and the credulity of most have confidently imputed : and therefore it cannot be expected , we should , in this place , so much as enumerate the one half , much less insist upon them all. sufficient it is , to the acquitance of our praesent debt , that we select the most considerable among them , and such as seem capital and comprehensive of all the rest . as for the power and influence of the stars , of which astrologers talk such wonders , and with such pride and ostent●t●on ; truly , we have reason to assure us , that our cognation and subjection to those ra●iant bodies , is not so great as that not only all the actions , fortunes , and accidents of particular men , but even the warres , peace , mutations , subversions of whole empires , nations , states , and provinces should depend upon their smiles or frowns : as if all occurrents on the theatre of our lower orb , were but the orderly and necessary effects of the praescriptions and consignations of the superior orbs ; or as if there were no providence divine , no liberty of mans will. ( ) as for the reciprocation , or afflux and reflux of the sea , so generally fathered upon the influx and motion of the moon , which doth herself suffer the like ebbs and floods of her borrowed light ; t is well known , how seleucus of old , and galilaeus of late , have more fully and roundly deduced it from the motion ascribed to the earth . and though we should allow this great phaenomenon to depend upon the several adspects or phases of the moon , yet is there no necessity to drive us to the subterfuge of any occult and immaterial influence from her waxing and waning light : since the system of des cartes in princip . philoseph . part . . page . ● doth much more satisfactorily make it out , from the elliptical figure of the sphere , wherein the moon moves ; as will soon appear to the examiner . ( ) as for the diurnall expansion , and conversion of the heliotrope toward the sun ; though great notice hath been taken thereof by the ancients , and most of our modern advancers of the vanities of natural magick ( who will have every plant to retain to some one of the planets , by some secret cognation , and peculiar sympathie . ) have laboured to heighten it to the degree of a wonder : yet can we not conceive the effect to be so singular , nor that any such solemne reason need be assigned thereunto . for , every mans observation may certifie him , that all marygolds , tulippa's , pimpernell , wartwoort , mallow flowers , and indeed most other flowers , so long as they are in their vigour and pride , use to open and dilate toward noon and somewhat close and recontract themselves after sun set . and the cause ( surely ) is only the warmth of the suns rayes , which discussing the cold and moisture of the praecedent night ( whereby the leaves were loaden towards the bottom , or in the bowle of the flower , and so made to rise more upright and conjoyn their tops ) and somewhat exsiccating the flower , make the pedestalls of its leaves more flaccid , so that they seem to expand and unfold themselves , and incline more outwards , meerly by reason of their want of strength to sustain themselves in an erect and concentrical posture : for alwayes the hotter the day , the greater is the expansion . likewise , as for the flowers conversion to , or confronting the sun in all its progress above the horizon , wherein our darksom authors of magick natural , principally place the magnale ; the cause thereof is so far from being more obscure than , that it is the very same with that of its expansion . for , as the sun running his race from east to west , doth every moment vary the points of his rayes vertical incidence upon the stalk which supports the flower , and upon the leaves thereof ; so must the whole flower incline its head and wheel about accordingly : those parts of the stalk upon which the rayes are more perpendicular , and so the heat more intense , becoming more dry and flaccid , and so less able to support the burthen of the ●●ower , than those , which suffer only from the obli●n● , reflected and weaker beams . notwithstanding this solution , if any champion of secret magnetism shall yet defend this circulation to be a 〈◊〉 of the heliotrop● , to which no other flower can praetend ; and that this solar plant discovers it amours to the sun , by not only disclosing its rejoycing head and b●som at the praesence , and wrapping them up again in the mantle of its owne disconsolate and languishing leaves , during the absence of its lover , but also by facing him all day long : lest he should insult , upon an apprehension , that our theory is at a loss , we shall tell him , in a word ; that that propriety , which he supposeth , must consist only in such a peculiar contexture and disposition of the particles , which compose its leaves , as makes them more sit to receive , and be moved , and their spiritual and most subtle parts to be in a manner circulated by the rayes of the sun , than the leaves of any other flower whatever . as in the organ of smelling , there is a certain peculiar contexture of its insensible component particles , which renders it alone capable of being moved and affected by odours , that have no influence nor activity at all upon the eye , eare , or other organ of sense . ( ) great things have been spoken also of the garden claver , which bareth its bosom , and hideth the upper part of its stalk , whenever the sun shines hot and bright upon it : but , this doubtless ) hath the same cause , as the former , the hiding of the stalk being nothing but an over-expansion of the leaves , which by reason of the violent ardour of the sun , grow more faint and flaccid , and so less able to support themselves . ( ) a fifth secret , found in the catalogue of caelestial influxes , is the crowing of the house-cock , at certain and periodical times of night and day , and more especially soon after midnight , and about day break : for , most esteem it an occult propriety , and all our crollians and such as promote the dreams of signatures and sydereal analogies , reckon the cock a cheif solar animal , for this reason alone ; as if his phansy received some magnetique touches and impressions from the sun , which made him proclame his a●vent into our hemisphere , and like a faithful watch or clock , measure out the severall stages in its race . great enquiry also hath been made after the cause hereof , in all ages , and various conceptions entertained concerning it . some with lofty and rhetorical discourses endevouring to persuade , that nature intended this 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ( as plu●arch 〈◊〉 it ) or gallicinium , as an alarme to rouse up sluggish man from the dull armes of sleep , and summon him to the early contemplation of her works ; as pliny ( natural . histor. lib. . cap. . ) others ascribing it to a desire of venery in this animal , arising from the turgescence and stimulation of his sperm , at certain periods ; as erasmus , who is therefore worthily and sufficiently derided by scaliger ( exercit. ) others assigning it to an appetite of aliment , invading and exciting after determinate intervalls ; as cardan . and others alleaging we ( nor themselves ) know not what peculiar influence of the sun , causing a suddain mutation , or evocation of the spirits and blood of the cock , which were concentred by sleep ; as caelias rhodiginus ( lib. . antiq. lection . cap. . ) but , all these great clerks seem to have graspt the ear , and catched at shadowes . for ( ) it may be doubted , that all cocks , in one and some meridian , doe not crow at the same times of night or day ; and that no cock doth observe set and punctual times of crowing ; both which are praesumed : and whoever shall think it worth the loss of a nights sleep , as we have done , to observe the crowing of sundry cocks in some country village , where the houses stand scatteringly and far asunder , so that the cocks cannot awake each other ; will , perhaps , more than doubt of either . ( ) it is , as natural , so familiar to the cock , so often as his imagination is moved by a copious and fresh afflux of spirits to his brain , to rowze up himself , clapp his wings , and sound his trumpet as well at noon , after noon , and at other times of day and night , upon several occasions ; as when he hath escaped some late danger , obtained a victory , found some treasury of grain , compressed his mistress , and the like ; as if his joy were not complete , till he had communicated the tidings thereof to his wives and neighbours , by the elevation of his gladsome and triumphat voice . ( ) may we not allowe the cock to have his set times of sleeping and waking , as well as all other living creatures , that live suo jure , and according to the aphorisms of their specifical constitutions , and regiment of their proper archaea's ; and likewise most men , who live healthfully and orderly , keeping to constant hours for labour , meat , rest and sleep ? ( ) what need is there that we should have recourse to such a far-fetcht ( and never brought home ) cause , as that of a secret commerce , and peculiar sympathy betwixt this fowl and the sun in the other hemisphere ; when we have a more probable and manifest one , neerer hand ; viz. the suddain invasion of the cock , by encreased cold soon after midnight ? for , when the sun hath made some sensible advance in the lower world , beyond the nadir point or midnight circle , and hasteneth toward our east ; he moves and drives along before him into our horizon , the ( formerly ) quiet and cold aer of the night : which invading the cock , disturbs him from his rest , during which his heat is retired inward , and awakens him on the suddain : so that rowzing up himself , exciting his courage , and diffusing his spirits again into his members , to oppose that cold , and perhaps also to prevent his falling from the perch ; he stands up , clappeth his wings against his sides , and chants a cheerfull paean to himself and roostfellowes , celebrating his safety and conquest with the loud musick of his throat . ( ) a sixth notable secret , appertaining to the same classis , is that of the encrease of the substance of shell fish , of the brains in coneys , and of the marrow in the bones of most land animalls , as the moon approacheth her full ; and the decrease of them again , as her light decreaseth toward her new. but , laying aside all lunar magnetism , immaterial influxes , and the like toyes put into great words ; we take it , the phaenomenon may be well enough solved , by referring it meerly to the moons great humidity ; at least , if those vast duskish spots , apparent in her orb , be her moist element , carrying some analogy to our seas , as the most and best of our modern astronomers have believed , and upon grounds almost demonstrative , and wholly irrefutable . for , insomuch as the rayes of the sun , in greater abundance falling upon the face of the moon , toward and at her full , than in her wane , are accordingly more abundantly reflected from thence upon our terraqueous globe , bringing along with them no sparing tincture of the moons moisture ; so that the light which is reflected from the oceans in the moon , being more moist than warm , must needs be more prolifical , generative , and praedisposed to the nutrition of animals : and that in the new of the moon no such plentiful abduction of her moisture can be expected , because fewer of the suns rayes are , at that time , reflected from her orb to ours ; why should it be thought so strange , that either aquatile , or terrestrial animals should be nourished more plentifully at the full , than new of the moon ? especially since it is no praecarious , nor novell assertion , that the light coming from the moon , ●s tincted with humidity , as being reflected from the watery as well as solid parts of her orb ; experience having frequently demonstrated , that the calorifick rayes not only of the sun , but even of our terrestrial and culinary fires , being trajected through various liquors , and other catoptricall bodies , or reflected from them , doe imbibe and carry off much of their virtues , and become thereby impraegnate , so as to be praedisposed to the production of sundry noble effects , such specially as relate to the alteration , germination , pullulation , and generation of vegetables and animals , both aquatile , and terrestrial . nevertheless , in case this cause assigned seem somewhat remote and obscure , we shall alleage another , sufficiently verisimilous to ease men of their wonder , at the fullness of the shell fish in the full moon , and their leane●● in the new ; and that is the encrease of the tides of the sea , which ascending higher upon the shoars , at the full moon , and washing down m●re of mudd , slime and saltness from thence , afford greater plenty of a●●ment to all shell fish : which delight in , and thrive best upon such k●nd of food , and are observed therefore to frequent foul and slimy shoa●● , and yet neerer and neerer to land , as the tides rise higher and higher , and again remove farther and farther off , as the tides sink lower and lower . ( ) to this classis also belongs the famous selenites , or moon-geeme , a certain praecious stone , found only in arabia , as dioscorides ( lib. . cap. . ) delivers : whose rare and singular faculty is this , that it repraesents the moon in all her several dresses of light , or apparences , encreasing 〈◊〉 lustre exactly as she encreaseth hers , and proportionately losing it 〈◊〉 relations be true , which have been made thereof by authors of the highest form for credit , namely pliny ( lib. . cap. . ) s. augustin ( de civit. d. lib. . cap. . ) zanardus ( de univers . element quaest . . ) nichol. caussinus ( lib. . symbol ● . ) ●oh . daniel mylius ( basilicae chymic . lib. . cap . ) and many modern mineralogists . now , for the reason of this rarity , in all liklihood , it must be if not the very same , yet cousin german to that of the former . because , it is very probable , that some certain portion of a thin , fluid and subtle matter ( we may conceive it to be hydrargycal , or relating to quicksilver , since all the forenamed authors describe the stone to be white and candent of colour . ) wherein the lustre of the stone doth mostly consist , doth suffer some alteration , according to the more and less of the lunar light incident upon it ; and is respectively circulated through the looser or less compacted parts of the stone , after the same manner as the more subtle and spiritual parts of some flowers are circulated by the rayes of the sun ; the particular configuration and contexture of its insensible particles being such , as dispose to that circulation , upon the influx of the moons light. in the inventory of special sympathies and antipathies , the first division concerns inanimate natures ; and among such the first place belongs to the attraction of i●on by the loadstone the second to the attraction of straws and other small and light bodies by amber and othe electrique● : but such is the singular excellency of the forme , that it not only deserves , but challengeth a singular chapter to its disquisition ; and the rea●on of the other we have plainly , thou 〈…〉 , in the precaedent section , the consideration of the wayes and instruments of all attraction natural , in the general , impelling us upon the anticipation thereof . in the third , we are to examine the secret amity of gold and quicksilver , of brass and silver ; which is so manifest , that whenever gol●●s dissolved in chrysulea or aqua r●gis , and the spirit or dissolution of quicksilver superadded thereto , the subtile e●fluvia streaming from 〈◊〉 particles of the gold , will instantly lay hold of , and at distance attract and firmly embrace the particles of the quicksilver , into which the dissolving liquor hath subtiliated it ; and in like manner , when brass and silver are dissolved in the same aqua fortis , their particles are observed to 〈…〉 to concorporation , though the spirits issuing from them , are not potent enough to perform an attraction , while the metals remain entire and in the mass . these effects we conceive may well be referred to 〈◊〉 correspondency or compossibility betwixt the figures of the insensible particles , of which the emissions from the gold , and brass consist and those of the pores , inequalities , and fastnings in the superfices of the granules of the dissolved quicksilver , and silver : but what those figures are on each part , is above our hopes of determination ; nor can we afford the curious any other light for conjecture in this true abstrusity , but what himself may perceive to arise to him by reflection from the reasons , we shall hereafter give , for the attraction of iron by a loadstone . in the mean while , we praesent him , for diversion of his scrutiny , with a short and opportune corollary . delightful it is , and indeed admirable to behold the granules of gold and silver , though much more ponderous than those of the aqua regis , and aqua fortis , to be notwithstanding held up , and constantly kept in a floating and elevated posture by them . and yet , in all likelihood the salt dissolved in those corrosive waters , must be the sole cause of that strange effect . for , the salts which are plentifully dissolved in those liquors , by a kind of mutual cohaesion of their insensible particles supporting each other from the bottom to the top of the glass , or other containing vessel ; doe sustain and bear up the granules of the metals which they have corroded and embraced . and this seems the more probable from hence ; that if common water , impraegnate with a few dropps of oyle of tartar ( that great instrument of separation ) be superinfused upon those tinctures , the granules of the dissolved metals suddainly disengage themselves from the arms of the corroding salts , and sink to the bottom : the fresh water yet father dissolving those salts , and giving them fuller fluidity ; so that becoming more attenuate , they lose their mutual cohaesion , and so their power of supporting ; and t is well known , that salt water will beare up such bodies , as will hardly swim in fresh . and this we take to be the general reason of all sorrs of praecipitation , practised either by chymists , or common refiners of metals : the oyle of tartar thereto conducing no otherwise , than meerly as it serves to the farther attenuation of the salt armoniack and other corrosive salts formerly dissolved in the strong waters . ( ) to the fourth , we assign the attraction of a less flame by a greater ; according to the erroneous dialect of the people : for , really it is rather the extension of a greater flame to the fewel of a less . for , the heat of a greater flame being proportionately more intense and diffusive , extends it self to the pabulum or nourishment of the less , where the same is situate within the sphere of its power : and thence it comes to pass , that the greater burning more strongly , by reason of that addition or augmentation of its fewel , doth more and more dilate it self that way , till at length it becomes wholly united to the less . which unexamining heads not understanding , have imputed to a certain attractive faculty in the greater flame , depending upon the identity of the two natures , or more praecisely , the same nature in two divisions and many have rackt their brains to erect subtle discourses thereupon , as if they wanted other opportunities to exercise their learning , and entertain their curiosity . ( ) to the fifth belongs the supposed attraction of flame by naphtha of babylon , at distance ; which is also improperly accounted an attraction : for the flame of its own accord flyeth to , and layeth hold of the naphtha ; and the cause of that involation is only this . from the body of the naphtha there is emitted in round a certain fat and unctuous , and so soon inflammable halitus , o● steam , which being extended to the borders of some flame posited at convenient distance , and thereby kindled in the extreme of its sphere , becomes enflamed all along the rayes , and they burning , soon bring home the flame to the body of the naphtha , from which they are emitted , in a continued ●luor . ( ) next to this , philosophers usually place the attraction of water by a spunge ; wherein they are as much mistaken as in either of the two last . for , the ascention of water into the pores of a spunge , so placed as to touch only the superfice of it , comes not from any appetite of attraction , or suction inhaerent in the spunge , as is generally praesumed and affirmed ; but onely from the depression , or downward impulse of the water by the swelling and sensibly dilating spunge ; and the manner of that series of motions is thus . the skirts or lowest parts of the spunge , touching the superfice of the water , immediately imbibe some parts of it into its pores , and becoming thereby dilated and tumid , press down the subjacent water to such a proportion as responds to the quantity of their owne expansion ; so that as they are more and more dilated by the admission of more and more parts of water into their cells or receptaries , it must be , that the water being more and more depressed toward the bottom , must rise higher and higher on the sides of the spunge , and insinuate it self into other and other pores successively , till the whole spunge be filled . manifest it is by experience , that if water or any other liquor , when it is though never so gently pressed in the superfice , find any the smallest chinks in the body pressing it ; it doth instantly rise up in round , and insinuate it self into those pores or chinks , the sides thereof in a manner sustaining it , and so praeventing its relapse or efflux . this we cannot but observe , when we dip the nose of our pen into ink ; the small cleft or slit in the lowest part of the quill , assisting the assent of the ink into the hollow thereof , and carrying up so much of it , as the mutual coherence of its parts will permit : for , if we dipp the point of a pen , which hath no slit , into a standish , we shall observe no such plentiful assent of ink ; there being no support or fastnings for it on each side of the nose , and so no obstacles to its relapse and sudden efflux . and , as for the reason , why water ascends , when it meets with any body , that is dry , filamentous or fibrous , and full of pores or chinks , such as a spunge , cloth , pen , &c. it may be most fully explained by the instance of a syphon , or pump . take a pipe of lead , of the figure of a carpenters squire , whose one arme is longer then the other ( such our wine coopers exhaust their buts of wine withal ) and immerse the shortest into a cistern of water , so as it may come very neer the bottom , and yet the longer arme rest upon the margin of the cistern , in a dependent or declining posture , then with your mouth suck forth the aer contained in the cavity of the pipe : and you shall observe the water quickly to follow on the heels of the aer , and flow in full stream out of the cistern through the pipe , without ceasing till all the water , that covers the shortest arme of the pipe , and so hinders the ingress of the aer into its orifice , be exhausted . of this the cause is only , that as your cheeks are inflated and distended by the aer , which upon exsuction comes rushing into your mouth , doe strongly move and impell the ambient aer ; so doth that , receding , move and impell the neighbouring aer , and that again moves and impels the next , till the impulse be propagated to the surface of the water in the cistern : and the water being thus depressed in the superfice , riseth up into the cavity of the pipe , which the extracted aer had newly deserted and left unpossessed ; nor doth it thenceforth cease to ascend and flow in a continued stream through the pipe , until all be exhausted . because , how much of water flows through the pipe , exactly so much of aer is , by impulsion , circulated into the place thereof ; the last round of aer wanting any other place to receive it , but what it provides for its self in the cistern , by depressing the water yet remaining therein : and thus the circulation once begun , is continued , till all the water hath past through the pipe . upon the same cause , or some other so like it , as t is no ease matter to discriminate them , doth that kind of percolation of liquors , and especially of aqua calcis , depend , which is made by a long piece of woollen cloth , whose one end lies in the liquor , and other hangs over the brim of the vessel that contains it . for , the liquor gently ascends and creeps along the filaments of the cloth , because , being though but very lightly prest in it superfice by the same , it doth proportionately ascend in round , to deliver it self from that pressure ; and by that motion impelling the incumbent aer upwards , it causeth the same to circulate and depress the surface of the liquor , and so makes it rise by insensible degrees higher and higher along the hairs and threads of the cloth , till at length it arrive at the highest part thereof resting upon the margin of the vessel ; and thence it slides down the decline or propendent half of the cloth , and falls down into the recipient , by dropps . and this motion is continued till all the liquor hath passed the percolatory , leaving the faeces adhaerent to the fibres of the same : each drop impelling the ambient aer , and driving it in round , or by a periosis , upon the surface of the water , so long as any remains in the vessel . and this , we conceive , may suffice to any mans comprehension of the reason of the repletion of a spunge , by water ascending ( not attracted ) into its cavities or pores . ( ) another eminent secret of sympathy , belonging to the same division , is that consent betwixt two lutestrings , that are aequisone : ( for unisone is hardly proper ) ; which is thus experimented . take lutes , or v●●s , and their treble , mean , or base strings being tuned to an equality of sounds , lay one of them upon a table , with the strings upward , with a small short straw equilibrated upon the aequison string : and then strike the aequison string of the other instrument , and you shall observe , both by the leaping off of the straw , and the visible trembling of the string , whereon it was imposed , that it shall participate of the motions of the string of the other instrument percussed ; all the other dissonous strings , as wholly unconcerned in the motion imprest , remaining unmoved . the like also will be , if the diapason or eighth to that string be percussed , either in the same lute or vial , or other lying by : but , in none of these , the consent is discernable by any report of sound , but meerly by motion . and yet the cause of this sympathy is not so very obscure , but the dullest pythagorean might soon have discovered it to be only this ; that the percussed string doth suffer a certain number of diadroms , or vibrations , and impress the like determinate motions upon the aer : which lighting upon another string of equal contexture and extension with the former percussed , doth impress the same motions thereupon , and impell and repell it so correspondently , as to make it suffer an equal number of diadroms . nor doth the aer hinder it in its several reciprocations or alternate excurses and recurses ; because the percussed string makes all its alternate excurses and recurses , at and in the same time , as the untoucht string doth , and so impels the aer alternately to the contrary side thereof . but , that agitated aer which falls upon a string of a different degree of extension , and so necessarily of a different tone ; though it impress various insensible strokes thereupon , yet are those impressed strokes such as mutually check and oppose each other , i. e. the excurses hinder the recurses : and therefore the string remains unmoved , at least as to the sense . likewise , the consent of another string , which makes that consonance , which musicians call a diapason or eighth , to that which is percussed by the hand , ariseth only from hence ; that the excurses and recurses of the string percussed by the hand , do not at all clash with , nor perturb and confound the excurses and recurses of the string moved immediately only by the aer , but are coincident and synchronical to them , and observe the same periods ; and so both agree in their certain and frequent intervals : more particularly , in an eight , every single diadrom of the longer and more lax string , is coincident to every second , fourth , sixth , &c. diadrom of the shorter or more tense string . nay farther , if the two strings be consonous though but in the less perfect consonance of a fifth ; yet shall the sympathy hold , and manifest it self ( which is not commonly observed ) by the tremulation of the untouched string , that is tuned to a fifth : because their diadroms are not wholly confused , each single diadrom of the longer or lower string , being coincident to every third , sixth , ninth , &c. diadrom of the shorter or more tense string . but if the two strings be dissonous , the sympathy fails ; because the excurses and recurses agree not in any of their intervals or periods , but perturb and confound each other ; as may be more fully understood from our praecedent discourse of the reason of consonances and dissonances musical . ( ) nor is it the inaequality of tension , disparity of longitude and magnitude , or non-coincidence of the vibrations in their several periods , that alone make two strings discordant ; for , if we admit the common tradition of naturalists , where an instrument is strung with some strings made of sheeps , and others of woolfs guts intermixed , the best hand in the world shall never make it yeeld a perfect consonance , much less play an harmonious tune thereupon . and the cause , doubtless , is no other than this ; that the strings made of a woolfs guts are of a different contexture from those made of a sheeps ; so that however equally both are strained and adjusted , yet still shall the aer be unequally percussed and impelled by them , and consequently the sounds created by one sort , confound and drown the sounds resulting from the other . to leave you in the less uncertainty concerning this , it is commonly observed , that from one and the same string , when it is not of an uniforme contexture throughout , but more close , even , and firme in some parts than in others ( all such our musicians call false strings ) there doe alwayes result various and unequal sounds : the close , even and firm parts yeelding a smart and equal sound , the lax and uneven yeelding a dull , flat and harsh ; which two different sounds at the same time created , confound and drown each other , and consequently where such a string is playd upon in consort , it disturbs the whole concent or harmony . it is further observed also , that the musick of an harp doth infect the musick of a lute , and other softer and milder instruments with a kind of asperity and indistinction of notes : which asperity seems to arise from a certain kind of tremor , peculiar only to the chords of that instrument . the like also hath been reported of other scarce consortive instruments , such as the virginalls and lute , the welsh harp and irish , &c. but you 'll object , perhaps , that the discordance of woolves and sheeps gutlings seemeth to arise rather from some formal enmity , or inhaerent antipathy betwixt the woolf and sheep : because it hath been affirmed by many of the ancients , and questioned by very few of the moderns , that a drum bottomed with a woolfs skin , and headed with a sheeps , will yeeld scarce any sound at all ; nay more , that a wolfs skin will in short time prey upon and consume a sheeps skin , if they be layed neer together . and against this we need no other defense than a downright appeal to experience , whether both those traditions deserve not to be listed among popular errors ; and as well the promoters , as authors of them to be exiled the society of philosophers : these as traitors to truth by the plotting of manifest falsehoods ; those as ideots , for beleiving and admiring such fopperies , as smell of nothing but the fable ; and lye open to the contradiction of an easy and cheap experiment . ( ) nor can we put a greater value upon the devouring of all other birds feathers by those of the eagle commixt with them ; though the author of trinum magicum hath bin pleased to tell us a very formall and confident story thereof : because we have no reason to convince us , that the eagle preys upon other fowls , out of an antipathy or hatred , but rather out of love and convenience of aliment ; and though there were an enmity betwixt the eagle and all his feathered subjects , during life , yet is there no necessity that enmity should survive in the scattered peices of his carcass , especially in the feathers ( that are but one degree on this side excrements ) which is praesumed to consist cheifly in the forme ; since those proprieties which are formal , in animals , must of necessity vanish upon the destruction of the forme , from whence they result . thus glow-worms project no lustre after death ; and the torpedo , which stupefies at distance , while alive , produceth no such effect though topically applied , after death : for there are many actions of sensible creatures , that are mixt , and depend upon their vital form , as well as that of mistion : and though they seem to retain unto the body , doe yet immediately depart upon its disunion . in the second division of special occult qualities , viz. such as are imputed to vegetables , the first that expects our consideration , is the so frequently mentioned and generally conceded sympathy , or mutually beneficial friendship betwixt some certain plants , as betwixt rew , and the figg-tree , the rose and garlick , the wild poppy and wheat ; all which are observed to delight and flourish most in the neighbourhood of each other , and our skilful gardners use to advance the growth and fructification of the one , by planting its favourite neer it . concerning this , therefore , we advertise ; that men are mistaken not only in the cause , but denomination also of this effect : supposing a secret friendship where is none , and imputing that to a certain cognation , or sympathy , which seems to proceed from a manifest dissimilitude and antipathy betwixt divers natures . for , wherever two plants are set together , whereof the one , as being of a far different , if not quite contrary nature , and so requiring a different kind of nourishment , doth substract and assimilate to its self such a juice of the earth , as would otherwise flow to the other , and deprave its nourishment , and consequently give an evil tincture to its fruit and flowers : in this case , both plants are reciprocally the remote cause of the prosperity each of other . and thus rew , growing neer the roots of the figg-tree , and attracting to its self the rank and bitter moisture of the earth , as most agreeable to its owne nature ; leaveth the milder and sweeter for the aliment of the fig tree , and by that means both assisteth the procerity of the tree , and meliorateth the fruit thereof . thus also garlick , set neer to a rose tree , by consuming the foetid juice of the ground , and leaving the more odorate and benigne to pass into the roots of the rose tree ; doth both farther the growth and germination thereof , and encrease the sweetness of it flowers . but , as for the amity betwixt the wild poppy and wheat , we should refer it to another cause , viz. the qualification of the ground by the tincture of the wheat , so as to praepare it for the generation and growth of the wild poppy ; not by substraction of disagreeing moisture , but by enriching the soyle , or impraegnating it with a fertility , determinate to the production of some sorts of weeds , and chiefly of that . for , most certain it is , that there are certain ●orn-flowers , which seldom or never spring up but amongst corn , and will hardly thrive , though carefully and seasonably set in other places : such are the blew-bottle , a kind of yellow single marygold , and the wild-poppy . ( ) this discovered , we need not search far after the reasons of those antipathies , which are reported to be between the vine and cole-woort , the oke and olive , the brake and reed , hemlock and rew , the shrub called our ladies seal ( a certain species of bryony ) and the cole-woort , &c. which are presumed to be so odious each to other , from some secret contrariety of their respective forms , that if any two of them , that are enemies , be set neer together , one or both will die . for , the truth is , all plants , that are great depraedators of the moisture of the earth , defraud others that grow neer them , of their requisite nourishment , and so by degrees impoverishing , at length destroy them . so the colewoort , is an enemy not only to the vine , but any other plant dwelling neer it ; because it is a very succulent and rank plant , and so exhausts the fattest and most prolifical juice of the ground . and if it be true , that the vine will avoid the society of the colewoort , by averting its trunck and branches from it ; this may well be only in respect of its finding less nourishment on that side : for , as the lord st. alban hath well observed , though the root continue still in the same place and position , yet will the trunk alwayes bend to that side , on which it nourisheth most . so likewise the oke and olive , being large trees of many roots , and great spenders of moisture , doe never thrive well together : because , the stronger in attraction of juice , deceives and starves the weaker . thus hemlock is a dangerous neighbour to rew ; because , being the ranker plant of the two , and living upon the like juice , it defrauds it of sufficient sustenance , and makes it pine away for penury . and the like of the rest . ( ) but what shall we think of that semiconjugall alliance betwixt the male and female palme trees , which is so strong and manifest , that the femal , which otherwise would languish , as if she had the green sickness , and continue b●rren ; is observed to prosper , and load her fruitful boughs , with braces of dates ; when she enjoys the society of the male : nay , to extend her arms to meet his embraces , as if his masculine influence were necessary not only to her impregn●tion , and the maturity of her numerous issue ; but even to her own health and welfare ? why , truly , we cannot better expound this dark riddle of nature , than by having recourse to some corpore●l emanations , deradiated from the male , which is the stronger and more spriteful plant , to the female , which is the weaker , and wants an accession of heat and spirits . for , far enou●h fr●m i●probable it is , that such ●●anation may contain much of the males s●minal and fru●t●●●ing vir●●● ; and it hath been avouched by freq●●nt experiments , that the blossoms and flowers of the male being dried and poudered , and inspersed upon the branches of the female , are no less eff●ctual to her comfort and fertility , than the vicinity of the male himself . we are told ▪ indeed , by heredotus , and from his own strict observation that the male palm pro●uceth yearly a dwa●fish sort of dates , which being uncapable of maturi●● and perfection , men use therefore to gather early , and bind them on the loaden branches of the female : that there corrupting , and breeding a kind of small volant in●ect , resembling our g●ats which the natives 〈◊〉 ps●●e , though theophrastus seems to appropriate th●t name only to those fiyes , th●t are a spont●neous pro●uction out of the immature fruit 〈◊〉 the wilde figg tree , suffering putrefaction● that they may advance the growth and maturity of her fruit ▪ not by any secret influence , but the ●an●●est voracity of those insects , which continually preying upon the ripening fruit , both open the top● o● them , an● so make way for the rayes o● the sun to enter more freely and deeply into their substance , and ●uck out 〈◊〉 of the luxuriant crude and watery juice , leav●ng the 〈…〉 ●nctu●us to the more easie digestion and assim●●●t●on of the ●ormerly ●●●rcharged seminal v●rtue of the plant this , we confess , is ●●ce an●●●●usible , but not totally satisfactory ▪ because it extends only to the re●●on of the males remote assistance of the female , in the maturat●●n of her fruit ; leaving us still to enquire , why she herself remains in a 〈◊〉 ●nd pining condition , unless she enjoys the society and invigorating 〈◊〉 of the male ; and why she inclines her amorous boughs toward his , as 〈◊〉 neighbourhood were a kind of divorce , and nothing less tha● absolute union could satisfie her affection . and what we h●ve heres●●● , of the sympathy betwixt the male and female palms , will not lose a ●rain of its verisimility , when our reader shall please to accomodate 〈◊〉 to the explanation of the cause of the like amity betwixt the ●ig ●ree , and caprificus or wild fig tree : of which pliny ( lib. . cap. . ) ●●lates the very same story , as herodotus doth of the palms . ( ) this puts us in mind of the great sympathy betwixt vine and wine , expressed from its grapes , and immured in hoggheads , though at the distance of many miles . for , it seems most convenient , that it is from the like diffusion of subtle emanations , imbued with the seminal tincture of the vine , that wines stored up in deep cellars , in the same country where they grew ( for , in england , whither all wines are transported over sea , no such effect hath been observed : the remove being too large to admit any such transmission of influence from the transmarine vineyards to our cellars ) become sick , turbid , and musty in the cask , at the same time the vines flower and bud forth : and again recover their former clearness and spirit , so soon as that season is past . and , that this conjecture may seem to smell the less of phansy , we desire you to consider , through what large tracts of aer even the odours ( exhalations much less subtile and diffusive , than those we conceive emitted from vines to wines ) of many aromaticks are usually diffused , in serene weather ; especially in respect of such persons , and bruit animals , as are exquisite in their sense of smelling . hath it not been observed , that the flowers of oranges have transmitted their odours perfect and strong , from great gardens to the nostrils of mariners , many leagues off at sea : nay , so far , that some sailers have discovered land by the smell of them , when their longest perspectives could not reach it ? doe not we frequently observe , that ravens will scent a carcass , at m●ny miles distance ; and fly directly to it by the chart of a favourable wind ? nay , are not there good historians that assure us , that eagles in italy , have sometime received an invitation by the nose , to come and feast on the dead bodies of men , in africa ? here , since we are occasionally fallen upon the large diffusion of some odours , especially to sage and unpraepossessed noses ; we shall take the advantage of that hint , to advertise you of a vulgar error , viz. that waters distilled of orange flowers and roses , become wholly inodorous , and phlegmatick , at the time of the blooming and pride of those flowers upon their trees . for , really those distilled waters are not in themselves , during the season of the flowers , from which they were extracted , less fragrant than at other times : but , because in the season of those flowers , they diffuse their odours so plentifully through the aer , and praepossess the nostrils , as that the odours of the waters , being somewhat less quick and strong , are less perceived , than at other times , when the aer is not imbued with the stronger and fresher odours , nor the olfactory nerves praeoccupied . and this may be inferred from hence ; that when the season of those ●lowers is past , and the smelling organ unoccupied ; the waters smell as fragrant as ever . for , as to the assuefaction of the sense of smelling , to particular odours , good or bad , we need not say much of that : since experience doth daily confirme , that the sense is scarce moved and affected by the same odour , though closely praesented , after custom hath once strongly imbued it with the same . sect . iii. in the third and last division of special occult qualities , or such as are vulgarly imputed to sensible creatures ; the pens of schollars have been so pro●use , that should we but recount , and with all possible succinctness , enquire into the verity and causes of but the one half of them ; our discourses would take up more sheets of paper , than are allowed to the longest chancery bill : wherefore , as in the former , so in this , we shall select and examine only a few of them , but such as are most in vogue , and whose reasons , is ●udiciously accommodated , suffice to the solution of the rest. ( ) the antipathy of a sheep to a woolf , is the common argument of wonder ; and nothing is more frequent , than to hear men ascribe it to a provident instinct ▪ or haereditary and invincible hatred , that a lamb ▪ which never saw a wool● before , and so could not retain the impression of 〈◊〉 harme done or attempted by him , should be invaded with horror and trembling , at first interview , and run from him : nay , some 〈…〉 the secret so far , as to affirme the antipathy to be equall on both 〈◊〉 . concerning this , therefore , we observe ; that the enmity is not reciprocal : for , he that can be persuaded , that the woolf hates the sheep ▪ only because he worries and preys upon him , and not rather , that the woolf loves the sheep , because it is a weak and helpless animal and its s●eth is both pleasant and convenient food for him : we shall 〈…〉 persuade him , that himself also hates a sheep , because he 〈…〉 pallate and stomach delighted and relieved with mutton . nor as the 〈◊〉 on the sheeps side invincible ; for , ourselves have see● 〈…〉 , by custom , to so great familiarity with a woolf , that 〈…〉 with him , and bleat , as after the dam , when the 〈…〉 of the room : and the like kindness have we 〈…〉 betwixt a lamb and lyon of the lord generall 〈…〉 sion house , and afterward publikely shewed in lond●n . 〈…〉 fear , which surpriseth the lamb at first sight of a 〈…〉 to arise from any hereditary impression derived from the 〈…〉 both● as well because all inbredd or traduced 〈…〉 , as that none of the progenitors of the lamb , 〈…〉 saw or received any impression of injury from a 〈…〉 in england . besides , in case they had , and though 〈…〉 that some beasts are afraid of men , and other beasts , 〈…〉 memory of some harme received from some man , 〈…〉 the idea of him , that did the harme , 〈…〉 upon the table of the memory , and being freshly 〈…〉 the 〈◊〉 , whenever the sense brings in the 〈…〉 not likely , that the same idea should be propa●●●● 〈…〉 , after so many hundred removes , 〈…〉 individual to the whole species , throughout the 〈◊〉 ▪ the cause , 〈…〉 , why all sheep generally are startled and o●●ended 〈◊〉 sight 〈…〉 , seems to be only this ; that when the woolf converts his eyes 〈…〉 pleasing and inviting object , and that whereupon 〈…〉 his imagination ; he instantly darts forth 〈…〉 of subtle effluvia's , which being part of 〈…〉 his newly formed idea of dilaniating and devouring 〈…〉 ●omposed , serve as forerunners or messengers of destruction to the 〈…〉 b●ing transmitted to his common sensory , through his opti●k nerve● most highly misaffect the same , and so cause the sheep to fear , an●●n●●avour the praeservation of his life , by flight . this receives sufficient confirmation from hence ▪ that not only such aversions , as arise from the contrariety of constitutions in several animals 〈…〉 commonly observed to produce those effects of fear , trembling and flight from the objects , from which offensive impressions are derived , by the mediation of disagreeing spirits or ema●ations : but even the seeing them in a passion of anger , or fury , doth suddainly cause the like . for , violent passions ever alter the spirits , and characterize them with the idea at that time most praevalent in the imagination of the passionate ; so that those spirits issuing from the body of the animal , in the height o● passion , and insinuating themselves into the brain of the other animal contrari●y 〈◊〉 , must of necessity highly disgust and offend it . which is the most likely reason that hath hitherto been given , why bees seldom sting men of a mild and peaceful disposition : but will by no means endure , not be reconciled to others of a froward , cholerick , and waspish nature . the same ▪ so may serve to answer that common quaere , why some 〈…〉 persons , having tuned their spirits to the highest key of 〈…〉 have daunted not only fierce mastiffs , but 〈…〉 other wild and ravenous beasts , meerly by 〈…〉 put them to flight by the artillery of their 〈…〉 eyes . and the key , wherewith we have unlockt the secret 〈…〉 and woolf , will also open those like antipathies supposed to be betwixt the dove and falcon , the chicken and kite , and all other weak animals , and such as use to make them their pr●y . ( ) it is worthy a serious remark , that sundry animalls bear a kind of 〈…〉 to the persons of such men , as are delighted or conversant in the destruction of those of the same species with them : as we daily see , that 〈◊〉 are highly offended and angry at butchers : that dogs bark 〈◊〉 and 〈◊〉 glovers , that deal most in dog skins , and 〈…〉 killing of dogs , in time of the plague , to praev●nt 〈◊〉 diffusion 〈…〉 and encrease of putrefaction , by their 〈◊〉 that vermin 〈◊〉 the trapps and gins of warrenners , where●● 〈…〉 their owne kind hath been taken and destroyed , &c. as 〈…〉 , or strong aversions , t is manifest , that they arise 〈…〉 , or character of providence 〈…〉 natures , or essential forms , but only 〈…〉 upon the sense . for the 〈…〉 any animal of the same species , excite a kind of horror in the like animal that smells them ; and so cause it to abhor and avoid all such persons and places , for fear of the like harm and internecion , as their fellowes have suffered from them . now , that which makes these odours insinuate themselves with such ●ase and familiarity into the sensories of animals of the same species , is the similitude and uniformity of their specifical constitutions , which yet the rough hand of corruption seems not totally to have obliterated in the long since extravenated blood and spirits , but to have left some vestigia or r●mains of the canine nature in the doggs blood , of the porcine in the sw●●●s , &c. and , that which makes them so horridly odious , is the great a●●●●●ion of the blood from its genuine temper and conditius . for , the smell of the carcass , or blood of any animal , having once suffered the dep●avation of corruption ; is always most hateful and dangerous to others of the same species : and it hath been observed , that the most pernicious in●ections and plagues have been such , as took their original from the corruption of humane bodies ; which indeed , is the best reason that hath ●een yet given , why the plague so often attends long and bloody sieges ▪ and is commonly the second to the sword. we conceive , the same to 〈…〉 the ground of that axiom of the lord st. alban ( nat. hist. cent . . ● ●enerally , that which is dead , or corrupted , or excerned , hath antipa●●●●●th the same thing , when it is alive , and when it is sound ; and with those 〈◊〉 which do excern : as a carcass of man is most infectious and odious ●●man , a carrion of an horse to an horse , &c. purulent matter of 〈◊〉 and ulcers , carbuncles , pocks , scabbs , leprousy , to sound flesh . and the excrements of every species to that creature , that excerneth them . but the exc●ements are less pernicious , than the corruptions . ( ) the 〈◊〉 ( and , according to some reports , the opening of the eyes● of the carcass of a murthered man , at the praesence and touch of the homicide . 〈…〉 in truth , the noblest of antipathies : and scarce any writer of the secrets or miracles of nature , hath omitted the consideration thereof . this life in death , revenge of the grave , or loud language of silent corruption , many venerable and christian philosophers have accounte●● holly miraculous or supernatural ; as ordained and effected by the just 〈◊〉 of god , for the detection and punishment of the inhumane 〈◊〉 . and , least we should seem too forward , to expunge , from 〈◊〉 mind of any man , the beleif of that opinion , which to some may 〈…〉 more powerful argument , than the express command of god , to 〈◊〉 them from committing so horrid and execrable a crime as mu●●er : we shall so far concurr with them , as to conceive this effect 〈…〉 divine only in the i●stitution , but meerly natural in the production , or immediate causes . because the apparence seems not to 〈◊〉 the capacity of natural means , and the whole syndrome and 〈◊〉 of it causes may be thus explained . it is an opinion highly c●●●entaneous , that in every vehement passion there is forme●● certain 〈…〉 well of the object , whereupon the imagination is 〈…〉 the good or evil connected unto , and expected from that objec● and that this idea is as it were impressed , by a kind of inexplicable 〈◊〉 upon the spirits , at the same instant the mind 〈◊〉 to will the praesent prosecution , or avoidance or the object 〈…〉 by the mediation of the spirits ( those angels of the mind ) the same idea is transmitted to the blood , and through the arteries diffused into all parts of the body , as well as into the nerves and muscles , which are inservient to such voluntary motions , as are requisite to the execution of the decrees and mandats of the will , concerning the prosecution , or avoidance of the object . this being so , we may conceive , that the phansy of the person assaulted by an assassine , having formed an idea of hatred , opposition , and revenge , and the same being characterized upon the spirirs , and by them diffused through the blood ; though the blood become much less fluid in the veins after death , by reason the vital influence and pulsifick faculty of the heart , which animated and circulated it , is extinct : yet , because at the praesence of the murderer , there issue from the pores of his body such subtile emanations , as are consimilar to those , which were emitted from him , at the time he strove with overcame , and killed the patient ; and those emanations entering the dead body , doe cause a fresh commotion in the blood remaining yet somewhat fluid in its veins , and as it were renew the former colluctation or duell betwixt the yet wholly uncondensed spirits of the slain , and those of the homicide : therefore is it , that the blood , suffering an estuation , flows up and down in the veins , to seek some vent , or salley-port ; and finding none so open as in that part , wherein the wound was made , it issues forth from thence . and , where the murthered person is destroyed by strangulation , suffocation , or the like unbloody death , so that there is no manifest solution of continuity in the skin , or other exterior parts of the body ; in that case , it hath been observed , that the carcass bleeds at the mouth , or nose , or both ; and this only because in all vehement strivings , and especially in colluctation for life , the spirits and blood flow most plentifully into the arteries and veins of the herd , as is visible by the great redness of the eyes and face of every man that fights ; and where the blood fixeth in most plenty , there will be the greatest tumult , aestuation and commotion , when it is fermented , agitated , and again set afloat , by the discordant effluvia's emitted from the body of the neer appro●ching or touching murtherer and consequently , there must the vessels suffer the greatest stress , distension , and disruption , or apertion of their orifices . ( ) and this magnale of the ( as it were ) reanimation of the vindictive blood in the veins of a dead body , by the magick of those hostile and fermenting aporrhaea's , transmitted from the body of him , who violently extinguished its former life ; ushers in another , no less prodigious , nor less celebrated by naturalists : and that is the suddain disanimation of the blood in living bodies , by the meer pr●sence of the basilisk , catablepa , and diginus ; serpents of a nature so transcendently venemous , that , according to pogular tradition , and the several relations of dioscorides , galen , pliny , solinus , aelian , avicen , and most other authors , who have treated of the proprieties of animals and venoms , they are dectructive beyond themselves , i. e. they either kill by intuition , or hiss out the flames of life by their deieterious expirations . if natural historians have herein escaped that itch of fiction , to which they are so generally subject , when they come to handle rarities ; and that nature hath produced any such spe●●es , whose optical emissions , or pectoral expirations are fatal and pernicious whether he sees the woolf first , or the woolf him ; suddain silence being ever the associate , ●or ( rather ) consequent of great and suddain fear . the aphonia , therefore , or defect of voice , which hath sometimes , though very rarely , been observed to invade men , upon the conspection of woolves ; is not the genuine effect of any secret and radicated antipathy , or fascinating virtue in the subtle aporrhaea's emitted from the eyes , lungs , or bodie of the woolf : but only of their own fear and terror , arising from a strong apprehension of danger ; the suddain and impetuous concentration of the spirits , toward the heart , by reason of the violent terror , at that time , causing a defection of spirits , and consequently a kind of relaxation in the muscles of the tongue , and nerves inservient to the vocal instruments : so that the inspired aer cannot be efflated with that force and celerity , as is necessary to the loudness and distinct articulation of the voice . ( ) nor is it the eye alone , that the folly of men hath made obnoxious to antipathies , but the ear also hath it share of wonderful effects ; for , there go solemn stories of inveterate and specifical enmities betwixt the lyon and cock , elephant and swine , and he hath read little , who hath not more than once met with sundry relations , that the crowing of the cock is more terrible than death , to the fiercest lyon , and the grunting of a swine so odious to an elephant , that it puts him into an agony of horror , trembling , and cold sweat . which notwithstanding , may well be called to the barre of experiment , and many worthy authors have more then questioned , among whom , camerarius ( in symbol . ) expresly assures us , that in his time , one of the duke of bavaria's lyons , breaking into a yard adjacent to his den , and there finding a flock of poultry , was so far from being afraid of the cock , or his crowing , that he devoured him and his troop of hens together . and as for the other antipathy ; ourselves have seen an elephant feed and sleep quietly in the same stable , with a sow and her whole litter of piggs . however , lest some should plead the power of custom , in both these cases , and object , that that lyon and elephant had been , by assuefaction , brought to endure the naturally hateful noises of the cocks crowing , and the swines grunting ; to eradicate the belief of the supposed occult antipathies , we say : that such may be the discrepancy or disproportion betwixt the figures and contextures of those subtile particles , that compose those harsh sounds , and the contexture of the organs of hearing in the lyon and elephant , as that they exasperate them , and so highly offend those animals . for , thus we suffer a kind of short horror , and our teeth are set on edge , by those harsh and vehement sounds , made by scraping of trenchers , filing the teeth of saws , squeaking of doors , and the like : only because those sounds grate and exasperate the auditory nerves , which communicate the harsh impression to the nerves of the teeth , and cause a stridor therein . ( ) but if we pass from these imaginary ▪ to real antipathies , and desire not to misimploy our understanding , in the quest of dihot●es for such things , of whose hoti the more sober and judicious part of schollars justly doubt ▪ let us come to the wonderful venome of the tarantula , a certain phalangium or smal spider frequent in italy , but most in and about tarentum in apulia ; which hath this strange propriety , that being communicated to the bodie of man , by biting , it makes him dance most violently , at the same time , every year , till he be perfectly cured thereby , being invincible by any other antidote but musick . an effect so truly admirable , and singular , that the discovery of its abstruse causes , and the manner of their operation , cannot but be most opportune and grateful to the curious ; who , we presume , would gladly knowe , why su●h as are empoysoned by the biting of a tarantula , fall int● violent fits of dancing , and cannot be cured by any other remedies , but the harmonious straines of musick alo●● ▪ solution . how great the power of musick is , as to the excitement , exaltation , and compescence or mitigation of the passions of the mind of man ; and wherein the c●use of that harmonical magick doth consist : would be a digression , and perhaps somewhat superfluous for us here to enquire . and , therefore , cutting off all collateral curiosities , we shall confine our present 〈◊〉 to the limits of our owne profession ; endeavouring only to explain the reasons , why musick hath so strong and generous an energy , as certainly to cure the bodie of a man , intoxicated with the venome of the taruntula , which eludes and despises the opposition of all other alexipharmacal medicaments . forasmuch , therefore , as the ●t●ings of a lute , vial , or other musical instrument , do alwayes mov● and impell the aer , after the same manner as themselves are moved an● impelled , and by this proportionate misture of sounds create an harmony delightful not only to the eare , but to that harmonious essenc● ▪ the soul , which animates the eare ; hence comes it , that by the musical harmony , that is made by the musicians play●●g to the person infected with the tarant●sme , the aer , by reason of the various and yet proportionate motions of the strings , is harmonically moved and agitated , and carying th●se various motions of the harmony impressed upon it self , into the eare , and so affecting the phantastical faculty with those pleasant motions , 〈…〉 like manner affect and move the spirits in the brain : and the spirits having received those impressions , and diffused into the nerves , muscles and 〈◊〉 of the whole body , and there meeting with a certain thin , acrimon●ous and pricking humor , which is the chief fewel and vehicle of the veno●e derived from the tarantula ; they attenuate and agitate the same , by a 〈◊〉 very like that of fermentation , and disperse it with a quick motion 〈…〉 all the parts . and this humor being thus set afloat , and estuated , to●●●her with the venome , or seeds of the poyson , which are contained 〈◊〉 , must needs affect all the musculousand nervous parts , 〈…〉 , with a kind of itch , or gentle and therefore pleasan● 〈◊〉 or ( rather ) titillation : so that the patient feeling this universa● 〈…〉 tickling , can be no longer at ease and quiet but is compelle● 〈◊〉 to dance and move all the members of his body with all agility 〈…〉 possible . this dancing causeth a commotion of all the 〈◊〉 in his body ; that commotion augments the present heat there●● ▪ that heat causeth a relaxation and apertion of the pores of th●●kin ; and thereupon ensues a liberal and universal sweat ; and together with that sweat , the venome is dispersed and expelled . but , where the venome is so deeply settled , and as it were radicated in the solid substance of the parts , as that one or two , or three fits of dancing and sweating are not sufficient to the total eradication and expulsion thereof ; in that deplorable case , the patient becomes freshly intoxicated , and relapseth into his dancing paroxisins , at the same periodical season , every year , without omission , till his many and profuse annual sweats have freed him from all reliques of the poyson . most true it is , that divers tarantiacal persons are affected with divers musical instruments , and divers tunes and ayrs ; but this is to be imputed to the diversity of complexions and temperaments either of the tarantula's , which envenome them , or of the persons themselves . for , such as are melancholy of themselves , or intoxicated by the poyson of the duller and more sluggish sort of tarantula's ; are ever affected and sympathize rather with the musick of drums , trumpets , sackbuts , and other loud and strong sounding instruments , than with that of lutes , vials , and other soft and gentle ones . for , since melancholy is a thick , heavy and viscid humor , and the spirit● alwaies follow the disposition of the humor praedominant ; to the concitation and dissipation thereof , a greater force of motion is required . and this , doubtless , was the reason , why a certain girl of tarentum , being there bitten by a tarantula , and affected with the stupendious symptome of tarantism , could never be excited to dance by any sounds , but those of guns , alarms beaten upon drums , charges and triumphs sounded in trumpets , and other military musick ; the heavy and viscid venome , meeting with a body of a cold and phlegmatick complexion ; and so requiring very strong commotions of the aer and spirits , to its estuation and dissipation . and , on the contrary , cholerick and sanguine complexions , are , by reason of the subtility of their spirits , and greater fluidity of their humors , soonest cured by the h●rmony of lutes , harps , vials , virginals , guitarrs , tiorba's , and other stringed instruments . but , that which deserves our highest admiration , is this ▪ that this venome of the tarantula doth produce the same effect in the body of man , which it doth in that of the tarantula it self , wherein it is generated ▪ as if there were some secret cognation and similitude betwixt the nature of that venemous spider , and that of mankinde . for , as the poyson , being infused into any part of mans body , and set a work by musick , doth , by a continual vellication or titillation of the muscles and membranes thereof , incite the intoxicated person to dance : so likewise , while it remains in its own womb and proper conservatory , the body of the tarantula being once set a work by musick , doth it incite the tarantula to dance , and caper , as is commonly observed by the italians , and at large related by at●an . kircherus ( in opere magnetico ) and some others of un questionable veracity , who would admit no testimony in this particular , but what they received from their own exact observations . among the sundry narrations of experiments in this kind , kircher entertains his reader cheifly with this one , as the most exact and commemorable . a certain italian duchess sayes he ) to the end she might be fully satisfied of the truth of this prodigy of nature , of which ●he had so often heard , and as often doubted , commanded that a tarantula should be brought into the hall , or refectory of a colledge of jesuits , all the fathers being praesent ; and there set upon a small chipp of wood , that floated 〈◊〉 of water . then she gave order , that an excellent harper shoul● stand by , and play over several of his best composed tunes . the tarantula , for a good while , seemed wholly unconcerned in the musick ▪ discovering no motions of tripudiation in himself ; but at length , 〈◊〉 the h●rper had hi● upon some certain notes strains , and ayres ▪ 〈◊〉 held some proportion to the humor and specifical venome of 〈◊〉 spider , ●he now enchanted insect began to detect its sympathy to 〈◊〉 , and natural inclination to dancing , not only by the frequent 〈…〉 , and nimble agitation of his whole body , but even most 〈◊〉 observ●ng time and measures , according to the harmoni●●● numb●●●●●prest in the tune : and as the musician plaid more slowly 〈…〉 the 〈◊〉 beast dance more slowly or nimbly ; not moving a 〈◊〉 after the t●m● was ended . but , this which then app●●r●d 〈…〉 the dutche●s and other spectators , they soon after heard 〈…〉 to the musicians of tarentum , who being hired , with an 〈…〉 paid out of the publique purse , to cure the meane● 〈…〉 when any is bitten by a tarantula ; that they may not 〈…〉 the patient , and put themselves to the pains of playing ●ong 〈…〉 enquire of the patient , in what house , what field , 〈…〉 of what colour and bigness the tarantula was , that 〈◊〉 him 〈◊〉 satisfied of these particulars , they forthwith go to the p●ace 〈◊〉 ▪ and there looking among the several species of tarantul●s 〈…〉 are busie in weaving their cobweb nets , for the ensnaring of 〈◊〉 they search for such a one as the patient hath described , and having 〈◊〉 found the like , they instantly fall to their instruments ; and pla● over 〈◊〉 sets of lessons one after another , till they light upon 〈…〉 holding some proportion to the specifical temperament and vene●●ous humor of that tarantula , inciteth him to dance . 〈…〉 delightful and strange it is to behold the great 〈…〉 among many tarantula's together ; one while this 〈◊〉 another 〈◊〉 that exactly sympathizing with the harmonious mo●io● 〈…〉 and aer . when the musicians have thus informed 〈…〉 particular genius and humor of that species of tarantu●●● by one 〈◊〉 which the patient was envenomed ; they return home , an● 〈…〉 almost at first touch of their instruments , playin● 〈…〉 again those tunes , whose correspondency to the 〈…〉 ambuscado ● in the centrals of his bodie , they 〈…〉 ●●perimented ▪ and they seldom or never fail of the 〈…〉 are certain what notes and tunes are most 〈…〉 genius of the spider , that hath intoxicated the 〈◊〉 . 〈…〉 inconsistent with reason , that the tarantula it self 〈…〉 strange effect from the charms of musick , as 〈…〉 venome hath intoxicated : for seeing that 〈…〉 supplies the office of blood in this insect is exceeding 〈…〉 with subtle and hot spirits , and so becomes a 〈…〉 receive the motions impressed upon it , by the 〈…〉 aer , whereof the sounds are composed : it seems 〈…〉 being a s●●ated and set afloat , by the motions of the aer , which are harmonical ; it should cause the like vibrissations in the nervous parts of the tarantula , as the hand of the musician hath caused in the consonous strings of the instrument ; the strings caused in the aer , and the aer caused in the spirits of the animal : and consequently , that the animal should suffer a kind of itch , or gentle vellication in all its nerves , and muscles , and to ease it self of that troublesom affection , move all its members , not only with great agility , but variety of motions correspnodent to those of the harmony impressed upon its spiritual substance ; especially where the harmony is proportionate to the specifical ( and perhaps , individual ) constitution of the same . that the vital humor of these and most other spiders , is both viscous , and a subject capable of sounds , as we here assume ▪ may be inferred from the relation of peter martyr ( in histor. sua indiae occidental ) that in the west indies there is a certain species of phalangiums , or venenate spiders , whose poyson , being expressed , is so exceedingly viscid and tenacious , that the natives use to draw and spin it out into long threads , and twist those threads into treble strings for their instruments of musick : as also from our own ocular testimony , whenever we press a spider to death . and ( what is of greatest moment to our praesent disquisition ) that the venome of the tarantula , by rea on of the acrimony , or mordacity of its spiritual and hot particles , causeth an uncessent titillation , or itching joyned wi●h great heat , in the nervous and musculous parts of mans body , when it is in aestuation and commotion therein , may be collected from the agreeing relations of all persons , who have known the misery of tara●tisme ▪ every one complaining of an insufferable itch in all parts of his body , during the paroxisme , and finding a remission of the same immediately after profuse sweating . for your farther confirmation herein , be pleased to hear father kircher tell you a memorable and pertinent story . a certain cappucine ( saith he ) of the monastery belonging to that order , in tarentum , being bitten by a tarantula , and by his ( in that point , too severe ) superiors forbidden to have recourse either to baths , or dancing , for the cure of his infection , as means that might seem too light and inconsistent with the gravity and rigid rules of his profession ; was so miserably and beyond all patience tormented with an itching and burning in both the interior and and exterior parts of his body , that rest and quiet were things he had long since been a stranger to ; and hoping to find some ease and allay of his restless pains by bathing in cold water , he , one night , privily conveyed himself out of the covent , and leaped into an arm of the sea , that embraced the town . where , indeed , he met with a perfect cure of a●l his torments and grievances ; being instantly drowned : leaving his brethren to lament their own great loss , as well as the sadness of his face ; and his superiors to repent the cruelty of that superstition , which had denied him the use of those innocent remedies , musick and dancing , which the happy experience of many thousands had praescribed . lastly , as it is not every harmonical ayre that suits with the genius of every tarantula , but every particular species holds a secret correspondence to some particular sorts of instruments , tunes , and 〈◊〉 composed of such and such notes : so likewise is it not the musick of every instrument , nor every modulation of sounds that move and excite every person infected with this kind of poyson ; but every tarantiacal patient requires such and such particular harmonious tunes , strains , and notes as are proportionate to that diathesis , or disposition , which results from the commixture and confermentation of his owne humors , and the venome infused into his body . which is the reason , why some dance to no musick but that of drums , trumpets and other loud and martial instruments ; and others again are easily charmed to levolta's by the mild and gentle consonances of lutes and tiorba's . and if the patient , being of a hot and bilious complexion , be intoxicated by the venome of a tarantula of the like cholerick temperament ; upon the aestuation and confermentation of those two consimilar humors , the patient shall become feverish , insatiately thirsty , restless , and furiously maniacal : but , where a melancholy tarantula hath empoysoned a man of the like dull and sluggish constitution ; in that case , he shall be infested with great and inexpugnable drowsiness , stupidity , spontaneous lassitude , love of solitude , unseasonable and affected silence , and the like symptoms contrary to the former , and shall be relieved only by grave and solemne tunes ; the accidents supervening upon this kind of intoxication , alwayes following and betraying the capacity of the praedominant humor , and responding to that harmony , which hath the most of proportion to the genius of the poyson . and as for the annual relapses of patients , into their tarant●acal fits ; the cause thereof must be only this , that the reliques of the poyson causing a fresh commotion and fermentation of the most susceptible humors of the body , and especially of the serous and bilious part of the blood ( for , most persons thus affected ; have their paroxysms in the hottest season of the year ) and imbuing them with exceeding great acrimony and mordacity : diffuse themselves through the arteries and veins into all parts of the body ; and fixing more especially on the thin membranes , that invest the muscles , so oppress , prick and vellicate them , as that the infected shall know no rest nor case , till he hath danced and sweat ▪ to the dissipation and expulsion of all those sharp and pungent particles , that were diffused into the habit of his body . but , what particular sounds , and notes , and strains , and ayres , are accommodate to the venome of this or that particular tarantula ; we leave to the determination of the long experienced musicians of tarentum only thus much we may say , in the general ; that by how much the more frequent diminutions of notes into halfs and quarters ( which is called division ) and the more frequent permistion of sharps and flats , in a tone charged with frequent semitones , the tune containeth : by so much the more grateful will the same be to all tarantulized persons ; because , from the celerity of the motions it comes , that the dormant venome is more nimbly agitated , and so must sollicite them to dance the more spritely and vehemently . hence is it , that the musicians of italy , such especially who proress the certain and speedy cure of the tarantisme , for the most part , enrich and adorne their strains with various divisions of notes ; and that mostly in the phrygian tone , because it consisteth of frequent semitones . ( ) what we have here said , concerning the magick of harmonious sounds both upon the tarantula it self , and those unhappy men , whom its fascinating venome hath tarantulized ; as it doth wholly take off the incredibility of those relations , which some natural magicians have set down , of the incantation of serpents , by a wand of the cornus , or dog tree : so doth it also give us no obscure light into the dark cause of that effect , which among the ignorant and superstitious hath ever passed for meerly praestigious and diabolical . for , it being certain , that all serpents are most highly offended at the smell , and influx of those invisible emanations proceeding from the cornus , by reason of some great disproportion or incompossibility , betwixt those subtile effluvia●s , and the temperament of the vital and spiritual substance of serpents : insomuch that , in a moment , they become strongly intoxicated thereby : why should it seem impossible , that he , who understands this invincible enmity , and how to manage a wand or rod of the cornus with cunning and dexterity ; having first intoxicated a serpent by the touch thereof , should , during that fit , make him observe and readily conforme to all the various motions of that wand : so as that the unlearned spectators perceiving the serpent to approach the enchanter , as he moves the wand neerer to himself ; to retreat from him , as he puts the wand from him ; to turne round , as the wand is moved round ▪ to dance , as that is waved to and fro ; and lye still , as in a trance , when that is held still over him ; and all this while knowing nothing , that the simple virtue of the wand is the cause of all those mimical motions and gestures of the serpent : they are easily deluded into a belief , that the whole seene is supernatural , and the main energy radicated in those words , or charms , which the impostor , with great ceremony and gravity of aspect mutters forth , the better to disguise his legerdemane , and dissemble n●ture in the colours of a miracle . and , as in this , so in all other magical practices , those bombast words , nonesense spells , exotique characters , and fanatick ceremonies , used by all praestigiators and enchanters , have no virtue or efficacy at all ( that little only excepted , which may consist meerly in the sounds , and tones in which they are pronounced , in respect whereof the eare may be pleased or displeased ) as to the causation of the effect intended ; nor doe they import any thing , more than the circumvention of the spect●●tors judgement , and exaltation of his imagination , upon whom they pr●etend to work the miracle . which considered , it will be an argument not only of christianism , but of sound judgement in any man , to conclude ; that excepting only some few particulars , in which god hath been pleased to permit the devil to exercise his praestigiatory power ( and yet , whoso shall consider the infinite goodness of god , will not easily be induced to beleive , that he hath permitted any such at all . ) all those volumes of stories of fascinations , incantations , transformations , sympathies of men and beasts with magical telesms , gamahues or waxen images , and the like mysterious nothings , are meer fables , execrable romances . so epidemical , we confess , hath the contagion of such impostures been , that among the people , when any person waxeth macilent , and pines away , we hear of nothing but evil neighbours , witchcraft , charms , statues of wax , and the like venefical fopperies ; and instantly some poor decrepite old woman is suspected , and perhaps acc●●●d of malice and diabolical stratagems against the life of that person : who all the while lieth languishing , of some common disease , and the le●●●ed physician no sooner examines the case , but he finds the sick mans consumption to proceed from some inveterate malady of the bodie , as ulcer of the lungs , hectique fever , debility of the stomack , liver , or other common concocting part , or from long and deep grief of mind . in like manner , when the husband man observes his field to become barren , 〈◊〉 chattel ●o cast then yong , or die , his corn to be blasted , his fruits 〈…〉 immaturely , or the like sinister accidents nothing is more usual 〈◊〉 , than to charge those misfortunes upon the magical impraecations of some offended neighbour , whom the multitude supposeth to be a 〈◊〉 man , or conjurer . and yet , were the philosopher consulte●●bou● those disasters , he would soon discover them to be the ordinary 〈◊〉 genuine effects of natural causes , and refer each contingent 〈◊〉 proper original . true it is likewise , that many of those sorcerers ▪ who● 〈◊〉 vulgar call white witches , in respect of the good they 〈…〉 frequently p●●●scribe certain amulets , or per●apts , for the praecentio● 〈…〉 of some di●●ases : and in this case , if the amulet or per●apt ▪ 〈…〉 such natural ingredients , as are endowed with qualitie● repug●●●● to the dis●●se , or its germane causes , we are not to deny 〈…〉 . but , as for those superstitious invocations of angels an● 〈◊〉 salamons characters , tetragrammatons , spells , circles ▪ an● 〈…〉 and ridiculous magical rites and ceremonies , used by the 〈◊〉 at the time of the composition or application of those amulets or 〈◊〉 ▪ they are of no power , or virtue at all , and signifie nothing but 〈◊〉 delusion of the ignorant . again , we grant , that the imagination 〈◊〉 confidence of the sick person , being by such means exalte● ▪ may 〈◊〉 very much to his recovery ; for , it is no secret , that the 〈…〉 men are for the most part , erected , and their drooping spirit● 〈…〉 by the good opinion they have entertained of the 〈…〉 confidence they place in his praescripts : but , yet are 〈…〉 allow any direct and natural efficacy to that 〈…〉 and ceremonious administration of remedies , which are 〈◊〉 observed by such impostors , as praetend to extraordinary skill ▪ an● 〈◊〉 supernatural way , in the cure of diseases , and seem to affect and 〈…〉 the detestable repute of magicians . and what we say of the 〈…〉 amulets , and the like , we desire should 〈…〉 , or love-procuring potions , o● the ligature 〈…〉 wedding night , to cause impotency in new 〈…〉 then brides a thing very frequent in zant and gasco●● 〈…〉 because each of these hath other causes , than those 〈…〉 nugaments praescribed by those cheaters ; and 〈…〉 they can have upon the persons , to whom they 〈…〉 in the praepossession of their phancy , and 〈…〉 to hope , or fear . ( ) 〈…〉 , a certain sort of fascination natural about which 〈…〉 and most nurses , when they observe 〈…〉 fall into cachex●es , languishing condition● 〈…〉 , instantly crie out , that some envious 〈…〉 them . concerning this secret therefore , in 〈…〉 part ) hath no interest at all ; we say ▪ that if there be any thing of truth , as to matter of fact , the fascinating activity of the old malicious crone must consist only in this : that she doth evibrate or dart forth from her brain , certain malignant spirits , or rayes , which entering the tender body of the infant , do infect the purer spirits , and so the blood in its arteries , and assimilating the same to their depraved and maligne nature , corrupt all the aliment of the body , and alienate the parts from their genuine and requisite temperament . not that those malignant emissions can arrive at , and infect an infant that is absent , as is vulgarly conceived ; but that the malicious old woman must be praesent , and look ( with an oblique or wist look ) and breath upon the child , whose health she envies , nay , conjure up her imagination to that height of malice , as to imbue her spirits with the evil miasme or inquinament of those vitious and corrupt humors , wherewith her half-rotten carcass is well stored ; and to assist the contention of her optique nerves and muscles , that so those spirits may be ejaculated with great force . for , that an old woman though as highly malignant in her nature and malice , as can be supposed , should be able to infect and envenome an infant at great distance ; is not to admitted by any , but such as have ignorance enough to excuse their perswasion of the highest impossibility imaginable . but , that she may , in some measure , contribute to the indisposition of an infant , at whom she shoots her maligne eye-beams , neer at hand ; may receive much of credit from the pollution of a lookinglass by the adspect of a menstruous woman ; and from the contagion of blear eyes , coughing , oscitation or gaping , pissing and the like : all which are observed to be somewhat infectious to the standers by . ( ) you may call it fascination also , if you please , when the torpedo doth benumb or stupifie the hand of the fisherman . for , as the maleficiation of infants is the effect only of certain malign or ill conditioned emanations transmitted to them from the brain of some malevolent and half venemous ruines of a woman : so likewise must the stupefaction of the hand of the fisherman , be the effect of certain stupefactive emanations , either immediately , or by the mediation of a staff or other continued body , transmitted thereunto from the offended fish ; which emanations , by a faculty holding some neer analogy to that of opium hyosciamus , and other strong narcoticks or stupefactive medicaments , do in a moment dull and fix the spirits in the part , that they invade , and so make it heavy , senseless , and unfit for voluntary motion . ( ) but , how shall we get free of that difficulty , wherein so many high-going wits have been gravell'd ; the sudden arrest of a ship , under sail , by the small fish echineis , thereupon general called a remora ? we cannot expede our selves from it , by having recourse to any fixing emanations transmitted from the fish to the ship ; because the motion thereof is not voluntary , but from external impulse ; nor hath the ship any spirits , or other active principles of motion , that can be supposed capable of alteration by any influx whatever . nor by alleaging any motion , contrary to that of the tide , winds , and oares , impressed upon the ship by the remora ; because , whatsoever kind of impulse or force can be imagined impressible upon it thereby : yet can it never be sufficient to impede and suppress the so violent motion thereof ; insomuch as the remora , neither adhaering to any rock , shelf , or other place more firme than the water , but only to the ship 〈◊〉 self , must want that fixation & firmitude , that is inevitably necessary , whenever any thing doth stop , or move another thing of greater weight then it self . what then ? shall we impeach of unfaithfulness all those authentick historians , who have recorded the suddain and prodigious arrests of the ships of peria●●er ▪ a●tigonus , and caius caligula , in the middest of their courses , though therein advantaged by the conspiring impulses of sa●ls and oares ? not so neither ; because many other vessels , as well before as since , have been stopped in the like manner : and there is in nature another cause , incomp●●ably more potent , and so more likely to have arrested them , than that 〈◊〉 , small and weak fish echmeis ; and that is the contrary motion of the sea , which our mariners ●who also have been often troubled with 〈◊〉 experiments of its retropellent force ) call the current ; which is alwayes most strong and cumbersome in narrow and aufractuous chanels . wh●●h being scarce known to the sea-men of those times , when navigation and hydrography were yet in their infancy , and few pilots so expert , as to d●●●●minate the several re-encounters , or contrary drifts of waters in 〈◊〉 ●nd the same creek or arme of the sea ; when they found any 〈◊〉 ●●ddenly retarded and impeded in its course , they never conceived that ●●moration to arise from some contrary current of waters in that pla●●●ut from some impediment in the bottome or keel of the vesse●●t sel● . 〈◊〉 ●s ●hey searched there for it , if it hapned twice or thrice , that they 〈…〉 small fish , such as the concha veneris , or any other not 〈…〉 , adhaering to the lower part of the rudder , or keel ; they instantly , 〈◊〉 without any examin●tion at all , whether so weak a cause might not be 〈…〉 to so great an effect , imputed the remoration of the●r 〈…〉 . historians , indeed , tell us , that the admiral galley , which ●●●ried the emperour caligula , in his last voyage to rome , was unexpecte● ▪ ar●ested , in the middest of all his numerous fleet ; and that an 〈…〉 found sticking to the bottom thereof : but they forgot to tell us , 〈◊〉 or no there were any other fishes of the same kind affixed to any 〈◊〉 of the galleys , that kept on their course ; and we have good ●●ason 〈◊〉 ●●njecture , that there were , because very few ships are brought into 〈◊〉 and docks to be carined , but have many small fishes , resembling 〈◊〉 ▪ adhaering to their bottoms , as ourselves have more than once obse●●●● in holland . besides , since , at caligula's putting forth ●●om astura 〈◊〉 island port , and steering his course for antium , his galley ▪ as is 〈◊〉 custome of admirals , kept up in the middle chanell ; 〈…〉 encountred and opposed by some special current , or violent 〈…〉 place , so streitly pent in on both sides by the situation o● certain 〈◊〉 and shelves , as that its greatest force was in one certain p●r● o● the ●●ane●l , and so not extensible to the other galleys of his navy , 〈…〉 ●owed neerer to the shoars , and so rode upon free water ? 〈…〉 are now adayes often arrested by special currents , in the 〈…〉 , whose chanels are rocky , aufractuous , and vorti●ou● 〈…〉 to frequent eddies and strong whirlepools ; and neer 〈…〉 every day behold the contrary drifts of ships by the 〈…〉 in the same arme of the sea ; some vessels being 〈…〉 whether the sea runs out , while others rice toward 〈…〉 sea run● in . ( ) so unlimited is the credulity of man , that some have gone farther yet from the bounds of reason , and imagined a second wonderful faculty in the remora , viz. the praesagition of violent death , or some eminent disaster , to the chief person in the ship , which it arresteth . for , pliny ( lib. . cap. . & lib. . cap. . ) will needs have it a prodigy portending the murder of caligula , which ensued shortly after his arrival at rome from astura : and that by the like arresting of the ship of perianders ambassadors sent to obtain an edict for the castration of all noble youths , nature did declare her high detestation of that course so destructive to the way of generation , that she had instituted for the conservation of her noblest species . but , every man knows , how easie it is to make any sinister accident the omen of a tragical event , after it hath happened : and that plinies remark upon the inhuman embassie , and succeeding infortune of perianders messengers , would better beseem the ranging pen or tongue of an orator , than the strict one of a philosopher . ( ) here , we should open and survey the whole theatre of venoms or poisons , on one hand ; and that of antidotes or counterpoisons , on the other : those operating to the destruction , these to the muniment and conservation of life ; and both by such qualities and wayes , as are generally both by physiologists and physitians , praesumed to be occult , or beyond the investigation of reason , and of which all that is known , is learned in the common school of experience . but , worthily to examine the nature of each particular poison , among those many found in the lists of animals , vegetables , minerals ; and explicate the propriety , by which its proper antidote or alexipharmacon doth encounter , oppose , conquer and expel it : must of necessity enlarge this section into a volume , besides the expence of more time , than what we have consigned to our whole work. and , therefore , we hope our reader will not conceive his expectation wholly frustrated , nor curiosity altogether defrauded ; though we now entertain him only with the general reasons , why poisons are hostile and destructive , why counterpoisons friendly and conserva●ive of life . gwoinus ( de venen . lib. . cap. . ) we well remember , defines venenum , poison , to be [ quod in corpus ingressum , vim infert , naturae illamque vincit ] that which being admitted into the body , offers violence to nature , and conquers it . and , according to this definition , by poisons we understand not only such things , as bear a pernicious enmity in particular to the temperament of the heart , or that substance , wherein the vital faculty may be conceived principally and immediately to consist : but all such as are hostile and destructive to the temperament of the brain , or any o●her noble and principal organ of the body , so as by altering the requisite constitution thereof , they subvert the aeconomy and ruine the frame of nature , wherein the disposition of the parts , to perform the actions of life , is radicated . and that , wherein this deleterious or pernicious faculty doth consist , we conceive to be a certain substance , which being communicated or infused into any part of the body , though in very small quantity , doth , by reason of the exceeding subtility and violent mobility or agility of the insensible particles , of which it is composed , most easily and expeditely transfuse or disperse it self through the whole body , consociate it self to the spirits , and invading the heart , brain , or other principal organ , so alter the requisite disposition or temperament and habit thereof , as to make it thenceforth wholly uncapable of performing the functions or actions of life , to which it was destined and framed ; and by that means introduceth extreme destruction . likewise , by alexipharmacal medicaments , or counterpoisons , we understand , not such things , as have only a propitious and benign friendship particularly for the temperament of the brain , heart , or other noble organ in the body , and are therefore accounted specifically auxiliant and corroborative thereunto , in the expulsion of ought , that is noxious and offensive unto it ; because , in that sense , all cardiacal , cephalical , and specifically corroborative medicaments would be alexiterial , and every peculiar venome would not require its proper antivenome , both which are contradicted by experience : but , such things as are endowed with faculties è diametro and directly contrapugnant to poisons , meerly as poisons ; for , divers things that are absolute poisons of themselves , and would destroy , if taken alone by themselves , do yet become powerful praeservatives and antidotes against other poisons , and afford suddain and certain relief to nature , when taken to oppose them . thus aconite , than which scarce any venome is more speedy and mortal in its operation upon a sound body , doth yet prove a praesent remedy to one bitten by a scorpion , if drank in wine : as pliny hath observed ( lib. . cap. . ) and that , wherein this salutiferous virtue of antidotes doth consist , we conceive likewise to be a certain substance , which being received into the body , though in small quantitie , doth with expedition diffuse it self throughout the same : and encountering the venome formerly admitted , and then operating , refract its energy , praevent its further violence , extinguish its operation , and at length either totally subdue , or totally educe it . for , all alexipharmacal remedies do not bring relief to nature , assaulted and oppressed by poison , by one and the same way or manner of operation ; some working by way of repulsion , others by way of abduction , others by way of opposition and downright conquest , when they are taken inwardly : some by retraction , others by extinction , where they are applied externally . thus triacle , whose basis or master ingredient is the flesh of vipers , doth cure a man empoisoned by the biting of a viper ; only because , in respect of consimilarity or similitude of substance , it uniteth it self to the venome of the viper , which had before taken possession of and diffused it self throughout the body , and afterwards educeth the same together with it self , when it is expelled by sweating , procured by divers cardiacal and hidrotical , or sudorifick medicaments commixt in the same composition : no otherwise than as soap , whose principal ingredient is oil , doth therefore take off oily and greasie spots from clothes ; because , uniting it self unto a cognate or consimilar substance , the oil or fat adhaering to the cloth , and so assisting its dilution and concorporation with the water , in which it self is dissolved ; it carrieth the same away together with it self in the water , when that is expressed or wrung out by the hand of the laundress . more plainly ; as oyle is therefore commixed with ashes , or salt , in the composition of soap , to the end it may not stain the cloth anew , to which it is applyed , but being confused with the oil or fat , wherewith the cloth was formerly stained , abduce or carry off the same together with it self in the water , which is the vehicle to both : so likewise is the flesh of vipers therefore commixt with so many alexiterial simples as concur to the confection of triacle , to the end it may by them be hindred from envenoming the body a new , but yet at the same time be so commixt with the venome already diffused t●rough the body , as that when those alexiterial medicaments are by s●●at or otherwise educed from the body , carrying along with them th● venome of the vipers flesh , to which they are individually consoci●ted , they may also abduce or carry away that venome of the vipers tooth , which was formerly diffused through the body . and this , we m●reover conceive , may be the general reason not only of the evacuat●on of venomes by sweat , where the antidote works by union and a●●uction ; but also of the evacuation of superfluous humours by elective 〈◊〉 , or purging medicaments , that specifically educe this , or that humor : for , it may be as lawfully said , that like may be cured by like , or 〈◊〉 by unlike ; as that oil may be absterged by its like , viz. the oil in so●p , and by something that is unlike , viz. the salt , or water carrying 〈◊〉 o●l individually commixt with it . thus also doth the body of a scorpion , being bruised and layed warm to t●● part , which it hath lately wounded and envenomed , suddainly retract , a●d so hinder the further diffusion of the poison that it had immitted into the body ; only because the nervous and fibrous parts of the scorpions body bruised , by a motion of vermiculation recontracting themselves , as chords too much extended , and so retracting the venome that yet remains adhaerent to them : do at the same time extract that consimilar venome , that was infused into the wound . the same also may be conceived of the cure of the venome of a spider by the body of the spider contused , and applied to the part envenomed : and of the cure of the biting of a mad dog , by the liver of the same dog , in like manner contused and imposed . nor is it by way of union and abduction alone , that some poysons become antidotes against others ; but also by that of direct contrariety , colluctation and conquest : for , there being great diversity of venoms , some must be contrapugnant to others ; and whenever any two , whose natures and proprieties are contrary one to the other , meet together , they must instantly encounter and combate each other , and at last the activity of the weaker submit to that of the stronger , while nature acting the part of a third combatant , observes the advantage , and coming in with all her forces to the assistance of her enemies enemie , completes the victory , and delivers her self from the danger . besides , we have the testimony of experience , that divers men have fortified their bodies against the assault and fury of some poisons , by a gradual assuefaction of them to others , as mithridates , and the attick old woman , &c. hence we remember another considerable secret concerning poisons , much disputed of in the school of physitians ; viz. whence comes it , that not only sundry particular persons , but even whole nations have fedd upon venemous animals and plants , without the least of harm , nay with this benefit , that they have thereby so familiarized poisons to their own nature , as that they needed no other praeservative against the danger of the strongest poison , but that venenate one of their own temperament ? whereto , we answer , in a word , that that tyrant , custome , alone challengeth the honour of this wonder ; such men having , by sensible degrees , or slow advance from lesser to greater doses of poisons , so changed the temperament and habit of their bodies , that the wildest venoms degenerated into wholesome aliments , and poisons were no more poisons to them , than to the animals themselves , which generate and contain them . which duely considered , we have little reason to doubt the verity of galens relation ( de theriaca ad pison . ) of the marsi , and aegyp●ians , whose ordinary diet was serpents : or of the like in pliny ( lib. . cap. . ) concerning the psyllae , tintyritae , and candei , who were all ophiophagi , or serpent-eaters : or of theophrastus his story ( lib. . de histor . animal . cap. . ) of certain shepherds in thrace , who made their grand sallads of white hellebor : or of avicens ( lib. . sen. . tract . . cap. . ) of a certain wench , who living upon no other viands but toads , serpents , and other the strongest poisons , and mostly upon that of napellus , became of a nature so prodigiously virulent , that she outpoisoned the basilisk , kissed several princes to death , and to all those unhappy lovers , whom her rare beauty had invited to her bed , her embraces proved as f●tal , as those of iupiter armed with his thunder , are feigned to have been to femele : or of iul. caes. scaligers ( exercit. . ) concerning the kings son of cambaia , who being educated with divers sorts of poisons from his infancy , had his temperament thereby made so inhumane and trans●endently deleterious , that he destroyed flyes only with his breath , kille● several women with his first nights courtship , and pistolled his enemies with his spittle ; like the serpent ptyas , that quickly resolves a man into his originary dust , only by inspuition , as galen reports ( de theriaca ad pison . cap. . ) the rear of this division of secrets concerning animals , belongs to the armarie or magnetick unguent , and its cousin german , the sympathetick powder , or roman vitriol calcined ; both which are in high esteem with many , especially with the disciples of para●●lsus , cro●lius , goclenius , and helmont , all which have laboured hard to assert their virtue in the cure of wounds , at great distance , either the unguent , or powder being applyed only to the weapon , wherewith the wound was made , or to some piece of wood , linnen , or other thing , to which any of the blood , or purulent matter issuing from the wound , doth ●●haere . concerning those , therefore , we say , in short ; ( ) that notwithstanding the stories of wounds supposed to have been cured by hoplochrism , both with the unguent and vitriol , are innumerable ; yet is not that a suffi●●ent argument to convince a circumspect and wary judgment , that either o● them is impowered with such a rare and admirable virtue , as their admire●● praesume : because many of those stories may be fabulous ; and were the several instances or experiments of their unsuccessfulness summed up ●nd alledged to the contrary , they would , doubtless , by incomparable excesses overweigh those of their successfulness , and soon counter-incline the minds of men to a suspicion at least of error , if not of imposture in their inventors and patrons . ( ) though the examples of their success were many more than those of their failing ; yet still would it be less reasonable for us to flye to such remote , obscure , imaginary faculties , as do not only transcend the capacity of our understanding , but openly contradict that no less manifest than general axiome , nihil agere in rem distantem : than to have recourse to a proxime , manifest , and real agent , such as daily producing the like and greater effects by its own single power , may justly challenge the whole honour of that sanative energy to it self , which the fraud of some , and incircumspection of others have unduly ascribed to the unguent , or sympathetick powder : we mean , the vital ( if you please , you may call it , the animal , or vegetative ) faculty it self ; which rightly performing the office of nutrition , doth by the continual apposition of the balsam of the blood , to the extremes of the small veins , and to the fibres in the wound , repair the lost flesh , consolidate the disu●●ted parts , and at length induce a cicatrice thereupon . for , common experience demonstrateth , that in men of temperate diet and euchymical bodies , very deep and large wounds are many times soon healed of themselves ; i. e. meerly by the goodness of nature it self , which being vigorous , and of our own provision furnished with convenient means , wholesom and assimilable blood , doth every moment freshly apply it to the part that hath suffered solution of continuity , and thereby redintegrate the same : especially when those impurities generated by putrefaction in the wound , which might otherwise be impediments to natures work of assimilation and consolidation , are removed by the detersive and adstrictive faculty of the salt in the urine , wherewith the wound is daily to be washed , according to the praescript of our sympathetical chirons . nor is this more than what dogs commonly do , when by licking their wounds clean , and moistning them with the saltish humidity of their tongues ; they easily and speedily prove their own chirurgeons . ( ) the basis or foundation of hoplochrism is meerly imaginary and ridiculous ; for , the assertors thereof generally dream of a certain anima mundi , or common soul in the world , which being diffused through all parts of the universe , doth constantly transferr the vulnerary virtue of the unguent , & vitriol , from the extravenated blood adhaering to the weapon or cloth , to the wound , at any distance whatever , and imbuing it therewith , strongly assist nature in the consolidation of the disunion . but , insomuch as this anima mundi , according to their own wild supposition , ought to be praesent to all other wounds in the world , no less than to that , from which the blood , whereunto the unguent , or vitriol is applied , was derived : therefore would it cure all other wounds , as well as that particular one ; since it interveneth betwixt that wound and the unguent or vitriol , by no more special reason , than betwixt them and all other wounds ; unless it can be proved , that some other special thing is transmitted to that particular wound from the unguent , and that by local motion through all points of the intermediate spaces successively ; which they will by no arguments be induced to concede . this verdict , i praesume , was little expected from me , who have , not many years past , publickly declared my self to be of a contrary judgment ; written profestly in defence of the cure of wounds , at distance , by the magnetick , or sympathetick magick of the weapon-salve ; and powder of calcined vitriol ; and excogitated such reasons of my own , to support and explicate the so generally conceded and admired efficacy of both , as seemed to afford greater satisfaction to the curious , in that point , than the romantique anima mundi of the fraternity of the rosy-cross , the analogical magnetism of helmont , or , indeed , than any other whatever formerly invented and alledged . and , therefore , to take off my reader from all admiration thereat , it is necessary for me here to profess ; that the frequent experiments i have , since that time , made , of the downright inefficacy and unsuccessfulness as well of the armary unguent , as sympathetick powder , even in small , shallow , and in dangerous wounds ; my discovery of the lightness and invalidity of my own and other mens reasons , adferred to justifie their imputed virtues , and abstruse wayes of operation ; and the greater probability of their opinion , who charge the sanation of wounds , in such cases , upon the sole benignity and consolidative energy of nature it self : these arguments , i say , have now fully convinced me of , and wholly converted me from that my former error . and glad i am of this fair opportunity , to let the world know of my recantation : having ever thought my self strictly obliged , to praefer the interest of truth , infinitely above that of opinion ▪ how plausible and splendid soever , and by whomsoever conceived and asserted ; to believe , that constancy to any unjustifiable conception , after clear conviction , is the most shameful pertinacity , a sin against the very light of nature , and never to be pardoned in a profest votary of candor and ingenuity ; and to endeavour the eradication of any unsound and spurious tenent , with so much more of readiness and sedulity , by how much more the unhappy influence of my pen , or tongue hath , at any time , contributed to the growth and authority thereof . chap. xvi . the phaenomena of the loadstone explicated . sect . i. whose wit had the best edge , and came nearest the slitting of the hair ; his , who said , that the loadstone is the real ianus , because of its two opposite faces , or poles , one whereof confronteth the north , the other the south : or his , who called it the egg and epitome of the terrestrial globe ; because as the egg contains the idaea of the whole and every part of its protoplast or generant , so doth the loadstone comprehend the idaea of the whole and every part of the earth , and inherit all its proprieties , being generated thereby , at least therein : or his , who named it the nest of wonders ; because , as a nest of boxes , it includes many admirable secrets , one within another , insomuch , that no man can well understand the mystical platform of its nature , till he hath opened and speculated them all one after another : or his , who affirmed it to be the antitype of the poets hydra ; because , no sooner hath the sword of reason cut off one head , or capital difficulty , but two new ones spring up in the place of it , nor ought any man to hope the total and absolute conquest thereof , but by cauterizing the veins of every difficulty , i. e. leaving not so much as the seeds of a scruple , but solving all its various phaenomenaes to the full : or his , who thought it sufficient , with aristotle , to call it [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] the stone , that singularity importing its transcendent dignity : we freely leave to the judgment of our reader . and , as for sundry other enquiries , that do not in any direct or oblique interest concern the investigation of the causes of all , or any of those admirable proprieties observed in the loadstone ; such as that of the various appellations given it by several philosophers of old , by several nations , at this day , together with the proper original , etymology and reason of each : whether it was first discovered by the shepherd magnes , on mount ida ; as pliny ( lib. . cap. . ) reports out of the records of nicander : whether its attractive virtue was known not only to hippocrates and other senior philosophers of greece , but also to the primitive hebrews , and aegyptians ; as gilbert conjectureth ( de magnet . lib. . cap. . ) : whether the knowledge of its ve●●icity , or polary virtue cannot be derived higher than the top of the four last centuries , and ought to be ascribed to a french man , together with the honour of the invention of the pixis nautica , or navigators compass , about the year of christ , m. cc. as ●assendus would persuade , out of one guyotus provi●eus , an old french poet , who not long after , writ a panegyrick in verse upon the excellency and sundry uses of the same ; or to iohn goia ( alias gira ) of salerna ▪ who lived not till almost an hundred years after the said guyotus had divulged his poem , as blancanus ( in chronolog . mathemat . sec l. . ) contends : whether the nations inhabiting the sinnae had the use of the mariners compass , before the europeans ; or whether they learned it of the european ships , that first advanced beyond the cape of good-hope , and coasted the mare rubrum , and begun commerce with them : all these things , as being not only not easie to determine , but also scarce pertinent to our praesent scope , we refer to our readers own enquiry , in gilbert , cabeus , kircher , and other authors , who promise him all possible satisfaction therein . to come , therefore , directly to the prosecution of our main design ; we observe , that the virtues of the loadstone are , in general two , one whereby it attracteth iron to it self , the other whereby it directeth both it self and iron ▪ which it hath impregnated by contact or influence , to the poles of the earth : the first is called alliciency , the other its verticity or polarity . concerning the cause of its alliciency , or the reason of the attraction of iron by the loadstone , or ( if you would have us speak in the sense and dialect of dr. gilbert ) the coition of iron and a loadstone ; various opinions have been conceived and asserted as well by modern as ancient philosophers . among those of the ancients , that which best deserves our commemoration and consideration , is the opinion of epicurus : who , lest he might seem scarcely sufficiently conscious of the great difficulty of the subject , excogitated a two-fold theory for its explication and solution ; the f●●mer of which we may easily collect from the commentary of lucretius thereupon ; the latter from the dispute of galen ( lib. . de natur . facult . ) against it . for , lucretius , professing to explain the reason and manner of the attraction of iron by the loadstone , according to the principles and judgment of epicurus , founds his discourse upon these four pillars , or praeconsiderables ; ( ) that all concretions do continually emit subtile effluvia's , or aporrhaea's : ( ) that the contexture of no concretion is so compact , as not to have many small vacuities , or insensible pores , variously intercepted among its solid and component particles : ( ) that the effluvia's streaming from concretions , are not equally congruous or accommodate to all bodies they meet with in the sphere of their diffusion : ( ) that the small pores , or insensible inanities intercepted among the particles of concretions , are not all of one and the same circumscription , or figure ; and so not indifferently accommodable or proportionate to all sorts of effluvia s issuing from other bodies , but only to such , as are symmetrical or correspondent to them in figure and magnitude . and then he proceeds to erect this superstructure thereupon . the attractive virtue of the loadstone , being determinate only to iron and steel ( which is purified iron ) seems to consist in this ; that both from the loadstone and iron there perpetually issue forth continued streams of insensible particles , or bodies , which more or less , according to their number and force of diffusion , commove and impel the ambient aer : and because the streams which flow from the loadstone are both more numerous and more potent , than those which are emitted from the iron ; therefore is the ambient aer alwayes more strongly discussed and impelled about the loadstone , than about the iron ; and so there are many more inane spaces therein created about the loadstone , than about the iron . that forasmuch as , when the iron is placed within the sphere of the aer discussed by the effluxions of the loadstone , there cannot but be much of inanity intercepted ( understand insensible inanity ) betwixt it and the loadstone ; thence it comes , that the aporrhaeaes of the iron tend more freely or uninterruptedly toward that part , which faceth the loadstone , and so are carried quite home unto it : and because they cannot tend thither in such swarms , and with such freedome , but they must impell the particles of the iron that are yet cohaerent together ; therefore must they also move and impel the whole mass of iron , consisting of those reciprocally cohaerent particles , and so carry it quite home to the loadstone . that , when a loadstone attracteth iron , not only through the aer , but also through divers compact and firm bodies , and particularly through marble ; we are to conceive that there are more and more capacious inanities made in that part of such interposed bodies , which respecteth the loadstone , than in that part of them , which confronteth the iron . that the reason , why other things , as straw , wood , gold , &c. being situate within the sphere of the aer discussed by the effluxes of the loadstone , do not in like manner emit their subtile particles in such numerous and potent streams , as carrying along their cohaerent particles with them , should move and impel their whole masses to a conjunction with it : is only this , that the particles emitted from the iron are alone commensurable to the inane spaces in the loadstone . that , because iron tendeth to the loadstone indiscriminately , i. e. either upward or downward , transversly or obliquely , according to the region of its application ; this indifferency could not be , but in respect of the introduced vacuities , into which the particles ( otherwise prolabent only downward ) are carried without distinction of region . and , lastly , that the motion of the iron towards the loadstone , is assisted and promoted by the aer , by reason of its continual motion and agitation ; and first by the exterior aer , which being alwayes most urgent on that part , where it is most copious , cannot but impel the iron toward that part where it is less copious , or more full of inanities , i. e. toward the loadstone : and afterward by the interior aer , which being likewise alwayes commoved and agitated , cannot but cause the stronger motion toward that part , where the space is rendred more inane . and this we conceive to be the summary of lucretius exposition of epicurus opinion touching the reason of the loadstones iron-attractive faculty . and galen ( in loco citato ) impugning the magnetick theory of epicurus , first makes a contracted , but plain recital thereof , in these words : a lapide quidem herculeo ferrum , à succino verò paleus attrahi , &c. quippe effluentes atomos ex lapide illo ita figuris congruere cum illis , quae ex ferro effluunt , ut in amplexus facile veniant ; quamobrem impactas utrinque ( nempe in ipsa tum lapidis , quam ferri corpora concreta ) & resilientes deinde in medium , circumplicari invicem , & ferrum simul pertrahi , &c. wherein , besides his usuall fidelity in the recitation even of such opinions of other men , as he thought good to endeavour to refute , we have good reason to believe , that galen came as near as possible to the true and genuine sense of epicurus : forasmuch as those four praeconsiderables alledged by lucretius for the support of his exposition of the cause and manner of the coition of the loadstone and iron , may be with equal congruity accommodated also to this latter epicurean solution of the same problem , according to this praesent interpretation and abridgement of galen . for , according to the tenour thereof , both the loadstone and iron are praesumed to consist of particles exactly alike in configuration , and to have the like inane spaces , or insensible pores intercepted among those particles : and this upon no slender ground , seeing that the loadstone and iron are perfect twinns , being both generated not onely in the same matrix , but of the same materials , one the same mineral vein of the earth . and , therefore , it is the more probable , that the particles or atoms issuing in continued streams from the loadstone , and invading iron situate within the orb of their activity , should easily and deeply insinuate themselves into the pores of the iron ; and there meeting with streams of other atoms so exactly consimilar to themselves , engage them to reciprocal cohaerence , and being partly repercussed or rebounded from thence toward their source , abduce those atoms along with them , to which they cohaere , and by the impulse of other cohaerent particles , abduce also the whole and entire mass : especially since it is part of the supposition , that the atoms transmitted from the iron to the loadstone , do reciprocally move , engage , and compel the particles thereof , after the same manner ; it being almost necessary that the atoms on both sides , in good part rebounding or resilient , toward their sources , and mutually implicated , should flow together into the medium , and so doing , that the whole bodies or masses of the iron and loadstone should be brought to a conjunction in the medium , because of the cohaesion of both sorts of the flowing atoms , with those , of which the whole masses are contexed . for , notwithstanding it be vulgarly apprehended and affirmed , that the iron doth come to the loadstone , rather then the loadstone to the iron ; that the streams of atoms emanant from the loadstone , are both more numerous and much more potent ; and found by experiment that pieces of iron do not only meet loadstones half way , but come quite home to them , where the loadstones are either much greater and weightier , or so held fast in a mans hand , or otherwise , as that they cannot exercise their reciprocal tendency : yet , as gilbert speaks ( de magnet . lib. . cap. . ) mutuis viribus fit concursus ad unitionem , the coition is not from one single attraction , but from a double , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or conactus . and , as for the reason , why other things do not apply themselves to the loadstone , as well as iron ; it may be said , that the streams of atoms flowing from the loadstone , and encountring those that are emitted from other bodies , do either pass uninterruptedly along by them , or are not , in respect of their dissimilitude in figures , so implicated or complected with them , as in their resilition to flow together and concurr in the medium . and then he attempts the subversion thereof , by the opposition of some arguments , and especially of these three quaeries . ( ) how such minute and insensible bodies , as those of which the magnetick aporrhaeas are supposed to consist , can be able to attract [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] so great a weight as that of a mass of iron ? whereto it may be answered , in behalf of epicurus , that the magnetick effluxes are not supposed to be so potent , as to draw any mass of iron of what weight soever , but only such a one , whose bulk or weight carrieth some proportion to the force of the attrahent , or loadstone . again , he might have considered , that the motions of the grossest and heaviest animals are performed by their spirits , that are bodies as exile and imperceptible as the magnetick effluviaes : that winds , which also consist of insensible particles , do usually overturn trees and vast aedifices , by the impetuosity of their impulses : and that subterraneous vapours are frequently the causes of earthquakes . and , as for the reason , how the magnetick aporrhaea's can deduce , apprehend , and detain a mass of iron ; he might have remembred , that the atoms of the magnet are conceived to have certain small hooks , or clawes , by which they may lay hold upon the ansulae , or fastnings in the iron ; to have a violent motion , which is the cause both of their impaction against , and resilition from the iron , and to have a perpetual supply of the like atoms continually streaming from the same fountain , by which they are assisted in their retraction , whereupon the attraction may ensue , and that so much the more forcible , by how much nearer the iron is praesented , in regard of the more copious efflux , or density of the magnetical rayes . ( ) how comes it , that a piece , or ring of iron , being it self attracted by a loadstone , and on one part adhaerent unto it , should at the same time attract and suspend another ring on the contrary part ; that second ring likewise attract and suspend a third , that third a fourth , that fourth a fifth , &c. to this we may apply that response of epicurus , which galen himself commemorates ; an dicemus , effluentium ex lapide particularum nonnullas quidem , ubi serro occu●saverint , resilire ; & has ipsas esse , per quas ferrum suspendi contingat ? nonnullas verò illud subeuntes , per inanes meatulos transire qu●m o●yssimè , & consequentèr impactas in aliud ferrum proximum , cum illud nequeant subi●gredi , tametsi prius penetraverint , hinc resilientes versus priu● , complexus alios prioribus similes efficere ? for , herein is nothing so incongruous , as galen conceives ; it being not improbable , that some of the magnetical atoms , falling upon a piece of iron should be impinged against the solid p●●ticles thereof , and others of them , at the same time , penetrate the sm●●● manities or pores betwixt those solid particles ; after the same manne● ▪ 〈◊〉 we have formerly asserted the particles of light to be partly r●fl●c●●d from the solid parts , and partly trajected through the pores of 〈◊〉 ●nd other diaphanous bodies : nor that some of those magnetick ray●● ▪ which pass through the pores of the first iron , should invade a second 〈◊〉 posited beyond it , and be impinged likewise against the soli● particl●● 〈◊〉 that , and so reflected toward their original , while some others pervading the in●nities of the second , should attract a third piece of iron , and so ●ons●quently a fourth , a fifth , and sometimes more . and ▪ certainly ▪ 〈◊〉 this case it is of no small advantage to epicurus , that the force of the magnetick attraction is so debilitated by degrees , as that in the seco●●●●on it becomes weaker than in the first , in the third than in the second ▪ in the fourth than the third , &c. until at length it be totally evira●● and decayed : because , upon the second there cannot fall as many ray●● ▪ as did upon the first , nor upon the third , as upon the second ▪ &c. as 〈◊〉 have at large explicated , in our discourse of the causes of the debilitat●●● of light. it may be further added also , in defence of epicurus ▪ that the atoms of the loadstone , penetrating the substance of iron , do so ex●●mulate the atoms thereof , that the iron instantly suffering an altera●●●n of the position of all its component particles , doth in a sort compo●e 〈◊〉 self according to their mode , and put on the nature of the loadstone it self : and therefore it can be no such wonder , that one iron magneti●●●d should operate upon another iron , as the magnet did upon it . but , all this ▪ 〈◊〉 confess , though it conferr somewhat of strength and plainness to the opinion of epicurus , cannot yet be extended so farr , as to equal the length of our curiosity , concerning the reason of the co●tion of the loa●●●one and iron ; and therefore it imports us to superadd thereunto so m●●● of the speculations and observations of our modern magnet●●●an au●●ors , gilbert , cabeus , kircher , grandamicus , &c. ( who have with more profound scrutiny searched into , and happier industry discovered 〈…〉 the mystery ) as may serve to the enlargement at least , i● not the full 〈◊〉 of our satisfaction . and , in order hereunto , to the en● peripicuity 〈◊〉 succ●●ctness may walk hand in hand together through our whole 〈◊〉 discourse ; we are to compose it of sundry observ●bles : 〈◊〉 as may not only conduct our disquisitions through all the 〈◊〉 and serp●●●●ne wayes of magnetism , and acquaint us with the seve●●● laws o●●●gnetick energy ; but also , like the links of a chain , sustain eac● othe● 〈◊〉 a continued series of mutual dependency and connexion . the first observable is ; that as well the loadstone , as its beloved mistress , iron , seems to be endowed with a faculty , that holds some analogy to the sense of animals ; and that principally in respect of attraction . for ( ) as an animal , having its sensory invaded and affected by the species of a grateful object , doth instantly desire , and is accordingly carried , by the instruments of voluntary motion , to the same : so likewise so soon as a lesser or weaker loadstone , or piece of iron , is invaded and percelled with the species of a greater or more potent one ; it is not only invited , but rapt on toward the same , by a kind of nimble appetite , or impetuous tendency . ( ) as sensible objects do not diffuse their species of colour , odour , sound , &c. to an animal at any distance whatever , but have the spheres of their diffusion or transmission limitted : so neither doth the loadstone , nor iron transmit their species or emanations each to other , at any distance whatever , but only through a determinate interval of space , beyond which they remain wholly insensible each of others virtue . ( ) as a sensible object , that is convenient and grateful , doth by its species immitted into the sensory of an animal , convert , dispose , and attract the soul of the animal ; and its soul being thus converted disposed and attracted toward that object , doth by its virtue or power , carry the body , though gross and ponderous , along to the same : exactly so doth the loadstone seem , by its species transfused , to convert , dispose and attract towards it the ( as it were ) soul , or spiritual substance of iron ; which doth instantly by its power or vertue , move and carry the whole mass , or grosser parts of it along to an union with the same . certainly , it would not easily be believed , that a thing so exile and tenuious , as is the sentient soul of an animal ( which is only flos substantiae , the purer and subtler part of its matter ) should be sufficiently potent to move and from place to place transfer so ponderous and unweildy a mass , as that of the body ; unless our sense did demonstrate it unto us , and therefore , why should we not believe , that in iron there is somewhat , which though it be not perfectly a soul , is yet in some respects analogous to a soul ; that doth though most exile and tenuious in substance , move , and transferr the rest of the mass of iron , though ponderous , gross and of it self very unfit for motion ? all the difficulty , therefore , which remains , being only about the manner , how the sentient soul of an animal is affected by and attracted toward a grateful object , let us conceive , that the sensible species , being it self corporeal , and a certain contexture of small particles effluxed from the object , such as do gently and pleasantly commove and affect the organ of sense , being once immitted into the sensory , doth instantly move the part of the soul , ( which is also corporeal , and a certain contexture of small particles ) inhaerent or resident in that organ , and evolving the particles of the soul converted ( perchance ) another way , and turning them about toward that part , from whence themselves are derived , i. e. toward the object , it doth impress a kind of impulse upon them , and so determine and attract the soul , and consequently the whole animal , toward the object . for , admitting this conception , we may complete the parallelism intended , thus ; as the particles of a sensible species , transmitted from a grateful object , and subingressing through the organ into the contexture of the soul , or sentient part thereof , do so sollicite it , as that it becomes converted toward , and is carried unto that particular object , not without a certain impulse of appetite : so do the particles of the magnetical species , subingressing into the soul of the iron , so evolve its insensible particles , and turn them toward the loadstone , as being thus sollicited , it conceives a certain appetite or impetus toward the same , and which is more , forthwith resalutes it , by diffusing the like species toward it . for , as if the iron were before asleep and unactive , it is awakened and excited by this exstimulation of the magnetical species ; and being as it were admonished , what is the propriety of its nature , it sets it self nimbly to work , and owns the cognation . but , by what other way soever it shall be explicated , how an animal is affected by , and rapt toward a sensible object : by the same way may it still be conceived , how iron is affected by , and rapt toward a loadstone . for , albeit as to divers other things , there be no analogy betwixt the nature and conditions of an animal , and those of iron : yet cannot that disparity destroy the analogy betwixt them in point of alliciency or attraction , here supposed . which well considered , scaliger had no reason to charge thales milesius with ridiculous madness , for conceding the loadstone and iron to have souls : as dr. gilbert ( lib. . de magnet . cap. . ) hath observed before us . the second ; that forasmuch as betwixt the loadstone and its paramour , iron , there is observed not only an attraction , or mutual accession , or co●●ion , but also a firm cohaesion of each to other , like two friends closely entwined in each others arms ; and that this cohaesion supposeth reciprocal revinction , which cannot consist without some certain corporeal instruments , that hold some resemblance to lines and hooks : hence 〈◊〉 it warrantable for us to conceive , that the species diffused from the loadstone to the iron , and from the iron to the loadstone , are transmitted by way of radiation , and that every ray is tense and direct in its progress through the intermediate space , like a small thread or wire extended , and this because it consisteth of myriads of small particles , or atoms flowing in a continued stream , so that the praecedent particles are still urged and protruded forward , in a direct line , by the consequent , after the same manner as the rayes of light flowing from a lucid body , the cause of whose direction must be their continued fluor , as we have formerly demonstrated , at large . we may further conceive , that as the rayes of light do pass through a perspicuous body ; so do the magnetical rayes pass thorow the body of iron . that as among all the lucid rayes incident upon a perspicuous body , whose side obverted to the luminary is of a devex figure , only one ray , viz. that which falls upon the middle point or centre , is directly trajected ; and all the rest are inclined or refracted toward that direct one , in their progress through the aer beyond ●he diaphanous body : so is only one of the magnetick rayes , incident upon iron , directly trajected through the same , and all the others are refracted or deflected toward that one direct . only here is the disparity ▪ that from the diaphanous body to the luminary no rayes are interchangeably transmitted : but from the iron to the loadstone there are ▪ and o● these also , in their permeation thorow the loadstone , only one is direc● ▪ and all the rest deflected toward that one . that forasmuch a● these m●gnetick rayes , being hence and thence refracted , and accordingly passing ●●orow the pores of the body of the iron , on one side , and those of the loadstone , on the other ; do variously intersect each other at certain angles , and in respect of those angles , become like so many arms embowed , or chords inflected , and so perstringe the solid particles interjacent among the pores : thence doth it come to pass , that the whole masses or bodies being thus , on this side and that interchangeably perstringed , there ensues the mutual adduction of the one to the other , or of the less or weaker to the greater or stronger ; and consequently the cohaesion of the one to the other , the devinction being , as the adduction , reciprocal . we need not advertise , that the magnetick rayes are so much stronger and tens●r than the luminous ; by how much they are more subtile and agile : being such as that in a moment they pass thorow a very great ma●s of marble , which the rayes of light cannot doe . nor that the magne●ique rayes do not attract marble , though they do attract iron posited beyond it ; nor strawes , or other lighter things interposed : because , except the loadstone and iron , no other bodies whatever do reciprocally emit and effect each other with their rayes ; nor have they that disposition of their pores or passages , which is necessary to the determinate refraction of the magnetique rayes , and to the constriction of their solid particles thereby . the third ; the magnetique species being diffused by deradiation excentrical , and the attraction of the loadstone ( of a spherical figure ) being therefore circumradious , or from all points of the circumference of its ●phere of energy : it will be requisite that we allow it to have ( ) a centre , as that which is on all sides corroborated by all the circumstant parts ; ( ) an axis , as that to which the virtues of all the circumjacent fibres are contributed ; ( ) the diametre of an a●quator , which lying in the middle of all its fibres , may also contain the strongest virtue of them all . for , having conceded this geometrical distinction of parts to a terrella , or spherical magnet ; we shall reap this advantage thereby , that we shall easily comprehend and describe the several reasons of laws and experiments magnetical . to particularize ; insomuch as the magnetique rayes are diffused from the centre of the loadstone to all points of it superfice , and beyond it to the bounds of their orb of activity ; that ray , which passeth through either of its poles , doth attract only by the force of the axis ; and that , which passeth through the aequator , draws only by the force of the diametre of the aequator ; and the other rayes , which like meridians , pass through the other parts , draw by a compound or complicated force , insomuch as they are alwayes intermediate betwixt one ray , which proceeds directly from the axis , and is parallel to the aequator , and another which comes directly from the diametre of the aequator , and is parallel to the axis . and , because the aequator is aequidistant from either pole ; thence is it , that an iron obelus , or needle , being praesented thereunto , shall be drawn parallel to the axis , and in a direct line to the diametre of the aequator : because all the rayes expiring from the axis , as they are the longest and strongest of all others , so are they also on each hand equal , and equally attractive of the extremes of the needle ; so that when it cannot incline to one pole more than to the other , as being aequilibrated by two equal rivals , it must consist in the middle betwixt them both . again , if the needle be praesented to any part of the terrella , beyond the aequator , toward either pole , in this case , because the ray issuing from the diametre of the aequator doth then display its virtue to the height , and that ●ay which is derived from the axis , is not of so much power as another longer one passing through , or near to the aequator : therefore shall the extreme of the needle , toward the nearest pole , feeling that stronger virtue , be somewhat inclined ; as if affecting to be conformed to that ray , which is direct to the diametre of the aequator ; and it shall be alwayes inclined so much the more , by how much longer that ray is , and the other , pro●●uent from the axis , the shorter . lastly , because in approaching very near to the pole , the one ray becomes very long , the other very short ( comparatively ) ; and so the ne●●le must be now almost right to the aequator : thence comes 〈◊〉 , that at the very pole , that extreme of the needle , which regards it , shall cohaere to the pole , and so the needle shall be ●●●posed in the same line with the axis itself . the four●h ; the loadstone being of such singular contexture , and so admirab●● comparated by nature , as that while it remains whole , the one half of its particles have a certain polary respect , or manner of con●●●sion to one part , and the other half to the opposite part ; and ●hen it is cut in two at the aequator , each segment , which formerly had all its particles converted one and the same way , doth in a mom●●● alter their respect , and convert the one half of them to one 〈◊〉 and the other to the contrary part : therefore doth a needl●●●●vigorated ) though all its particles were before indiscriminately and confusedly posited , likewise in a moment obtain a conversion o● one half of its particles to one part , and of the other half to the contrary part ; and this either from its long situation above the eart● ▪ or affriction to a loadstone , or to another needle strongly m●●netified . and this is that prodigious propriety of magnetical 〈◊〉 , which cabeus calls facultatem duarum facierum , a faculty of 〈◊〉 faces ; and kircher [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] biforme● facultatem ▪ though they differ beyond reconciliation in their reasons , or explications of ●t . but , though this janus quality be in common as well to iro● as to the loadstone it self ; to the former , onely by infu●ion , t● the latter by essence : yet are we to allow this difference , that 〈◊〉 poles of the loadstone are never to be changed from one extreme to the other ; but those of a needle are easily capable of trans●●●ntation , so that the cuspis , which now is strongly affected to the north , may in a minute be alienated and inspired 〈…〉 to the south , onely by a praeposterous affriction of 〈…〉 loadstone . and hence comes it , that as the north pole 〈◊〉 one loadstone doth not attract or unite with the north pole of ●nother loadstone ; so doth not the north cuspis of a needle 〈◊〉 it self to the north pole of a loadstone ; provided ●t be 〈◊〉 praesented , not applyed , or affricted upon it . for , 〈…〉 touch or affriction of the loadstone , the cuspis from 〈…〉 a verticity ● diametro opposite to its former : in ●ase it be 〈◊〉 upon a contrary pole , or upon the same pole with 〈…〉 ductus . hence also is it , that if you fill a 〈…〉 or powder of a loadstone , and offer it to either 〈…〉 of a whole loadstone ; it shall remain altogether 〈…〉 ●nfluence , and acquire no verticity at all : because 〈…〉 of the powder , intruded into the quill , have 〈…〉 some respecting this , others that , others a quite contrary region . but , if you exchange the filings of loadstone for the filings of steel , and offer either of the extrems of the quill to either pole of a loadstone ; it shall instantly own the magnetique influx , and be imbued with the polary virtue , or directive faculty thereof : and this , because all the granules of the steel powder , wanting determinate poles of their own , are indifferently disposed to admit and retain the virtue of either pole of the loadstone , in any part . if this be true , you 'l ask us , how it comes about , that the northern pole of one loadstone doth not only not attract , but nimbly repel or avert the northern pole of another loadstone , if they be brought within the orb of their power ? and we answer ; that the aversion is not really from the repulsion of one north pole by the other , but from the attraction of the south pole , which is felt and owned at that distance : but , because the south pole cannot be detorted toward the north , but the north pole of the other loadstone must receed and veer from it ; therefore doth that conversion seem , indeed , to be a kind of fugation , which really is only an attraction . the same is to be understood of the austrine pole of one loadstone , in respect of the austrine pole of another ; and also of either cuspis of a needle excited as well in respect of another needle invigorated , as of a loadstone . the same also of a loadstone dissected according to its axis , when the divisions or segments being never so little dissociated , doe not attract each other respectively to their former situation ; but the austral part of the one segment is wheeled about to the boreal part of the other : and so of the other poles ▪ the contrary whereunto alwayes happens , when a loadstone is dissected according to the aequinoctial . and from this one fountain flow these three magnetique axioms . ( ) contraria contrarijs sunt amica ; similia similibus inimica : i. e. magnetical poles of the same aspect and apellation , are alwayes enemies , and decline both commerce and conjunction each with other ; and poles of a contrary respect and denomination , are alwayes friends , and affect and embrace each other . for , to all magneticks this is singular ; that those par●s , which are friends each to other , ever regard opposite regions , and convert to contrary points ; but those , which are enemies , regard the same region , and convert to the same point : because friendly parts may constitute the same axis ; but adverse cannot . ( ) quae eadem sunt uni tertio , non sunt eadem inter sese ; i. e. two poles of the same respect and name , are both friends to a third pole of the contrary respect and name : but yet they are enemies and irreconcileable among themselves . and hence comes it , that a third pole , being offered to either of two friendly poles , cannot be a common friend , but a necessary enemie to either . for , those poles , which are friends , are of a contrary respect , one septentrional ▪ the other meridional : to which a third cannot approach , unle●s it be a meridional , that ●hall be an enemy to the meridional , or a septentrional , th●● shall be an enemy to a septentrional : because , poles of the same aspect , cannot compose the same axis , but those of a contrary 〈◊〉 . and this starts up another singularity of magnetiques ; that there can be no more than two twin●s : ●nsomuch as more than two cannot compose the same axis , in the same part . ( ) ●irtus ex eadem ●onte petita , inimica & noxia ; ex contrarijs fontibus , amica & jucunda . for , if you imbue the head● of two needles with the virtue of the same pole , their heads shall reciprocally turn away ●ach from other , and mutually destroy each others verticity : but , 〈◊〉 you imbue th●m with the virtue of contra●y poles , they shall unite and mutually conserve each others verticity . likewise , if a long needle be applyed , in the middle , to either pole of a loadstone , and ●hen be cut off in the place of the late contact ; the new extrem●● formerly united in the middle ) shall instantly display contrary virtues ▪ ●nd re●iprocally avoid each other . and here , 〈◊〉 oath of allegiance to truth , whereby we are obliged to serve he●●pon all occasions , will excuse our digression , if we st●p a little asid● 〈◊〉 the so famous sepulchre of that greatest of impostors , maho●e● ▪ and observe how egregiously false that common report is , conc●●ning the suspension of his iron tomb in the aer , by the equal virtues of two loadstones , the one fixt above in the arched root , th● other beneath in the floor of his temple at medina talnab : in 〈◊〉 . if we consult the relations of travellers concerning it , we shall not only not meet with any , who affirms it upon any other g●●unds , but the tongue of popular fame , and tradition of the ●●●●itude : but also with some , that expresly contradict it : for , 〈◊〉 v●ssius tells us , both gabriel sionita , and iohann●s h●sronita , 〈◊〉 le●rned maronites , who journied to medina on purpose to satisfie themse●●es and others in that point , positively deliver , that the tomb o● maho●●● is made of white marble , and stands upon the ground in the east end 〈◊〉 ●hat mosque . les voyages fameux du sieur vincent l● blanc marseillois , p. . l . c. quant a la ●●lle de medine , quelques-uns ont donné ● entendre que le sepulchr● d● mahomet estoit la , ou ● la meque , tout de fer & suspendu 〈…〉 par le moyen de quelques pierres d● aymant : mais ● est une c●ose tres fausse , esta●t bien certain , comme i e l' ay appr●● sur le 〈◊〉 mesme , que ce faux prophete mourut & fut enterre a m●●ine ▪ 〈…〉 voit encore son sepulchre for t frequente de pelerins mahometans 〈◊〉 les quartiers du monde ▪ comme est le sepulchre de ierusalem de 〈◊〉 les chrestiens . ce sepulchre est de marbre blan● ; ave● 〈…〉 ebube●er , ali , omar , & otman califs , successeurs de ma●omet , 〈…〉 au pres de soy les livres de sa vie & de sa secte , 〈…〉 &c. and , if we consult our own reason , considering the setled 〈…〉 alterable laws of magnetical attraction ; we shall soon be 〈◊〉 not onely of the monstrous falsity , but absolute impossibility 〈◊〉 the effect . for , should we grant it to be in the power of 〈◊〉 industry , to place an iron so praecisely in the neutral point of the medium betwixt two loadstones , equally attracting it , the one upward , the other downward ; as that the gravity of the iron , and downward attraction of the inferiour loadstone might not exceed , nor be exceeded by the ●pward attraction of the superiour loadstone , and so the iron should remain , without any visible support , aequilibrated betwixt them , i● the aer : yet could not that position of the iron be of any duration ; because , upon the least mutation of the temper of the iron , or motion of it by the waving of the aer from high winds , and divers other causes , the aequilibration must cease , and the iron immediately determine it self to the victor , or strongest attractor . but , since what is here supposed , is wholly repugnant to the experience of all , who have or shall attempt so to aequilibrate an iron in the aer betwixt two loadstones , as that it shall not feel the attractive virtue of one more strong than that of the other : we need not long study what to think of the suspension of mahomets iron chest. nor is it less impossible , that an iron should be held up , at distance , in the aer , by the virtue of a loadstone placed above it : insomuch as that force , which at first is sufficient to overcome the resistence of the irons gravity , and elevate it from the ground , must , as the iron approacheth nearer , be still more potent to attract it ; and so that cannot oppose the attractive energy of the loadstone , in the middle of it sphere , which was forced to submit and conform unto it , in the extremes . this we may soon experiment , with a needle by a thread chained to a table , and elevated perpendicularly in the aer , by the pole of a loadstone : for , the needle will nimbly spring up to meet the loadstone , so farr as the thread will give it scope ; and if the t●read be cut off , it instantly quits the medium , and unites it self to its attractor , from whose embraces it was before violently detained . hereupon as we may assure our selves , that dinocrates , that famous architect , who , as pliny relates ( lib. . cap. . ) began to arch the temple of arsinoe in alexandria , with loadstones , that so her iron statue might remain pendulous in the aer , to excite wonder and veneration in the spectators ; but was interrupted in the middle of his work both by his own death , and that of ptolomy , arsinoes brother , who expired not long before him ; died most opportunely in respect of his reputation , because he must have failed of the chief design , though he had lived to finish his structure : so also can it be no longer doubted , that ruffinus his story , of the iron chariot in the temple of serapis , and beda's of the iron horse of beller●phon , sustained by loadstones so cunningly posited , as that their virtues concurr and become adjusted in one determinate point ; are meer fables , and fit to be told by none but doating old women in the chimney corner . the fifth ; as one loadstone is stronger in its attractive virtue than another , though of the same , nay , perhaps , much greater bulk and weight ▪ so is some iron more disposed than other , both to admit and conform to the attraction of a loadstone , and , after invigoration , to attract and impraegnate other iron . as for the vigour and perfection of a loadstone ; it consisteth both in its native purity , and artificial politeness . ( ) in its native purity ; for , if no dross or heterogeneous substance be admixt to the magnetick vein in the earth , from which a magnet is extracted ; then is that loadstone superlatively potent and energetical in attraction : and among loadstones of this sincere and homogeneous constitution , there are found no degrees of comparison , but what the difference of their several bulks doth necessarily create . but , in case any heterogeneous matter be commixt with the magnetick seeds or particles of a loadstone , at its concretion ; as it for the most part falls out : then must the attractive energy of that stone be weaker , according to the proportion of that spurious matter admixed thereunto . this may be confirmed from hence ; that some very small loadstones are more potent than very great ones ; of which sort shall we account that of which mersennus ( de magnete ) affirms , that weighing but gr. in all , it would nimbly attract and elevate a mass of iron times higher than it self : and from hence , that some stones that were dull and languid before , after the secretion of their drossy and impure parts , become very active and potent . thus , when any heterogeneous substance hath been , like a cortex or shell circumobduced about a loadstone , in its concretion ; if the same be pared or filed away , and the remaining kernel be polished ; its virtue shall be augmented to a very great proportion . ( ) in its artificial tersness or politeness ; for , by how much smoother a loadstone is , in it superfice , with so many the more rayes of virtue , both attrahent and amplectent or connectent , doth it touch iron oblated unto it ; and è contra . likewise , as for the more or less praedisposi●ion of iron , both to receive the attractive influence of a loadstone , and , after excitement to attract other iron ; this also consisteth either in its more or less of native purity , or of acquired politeness : because , how much the nearer it comes to the pure nature of steel , by so many the more parts hath it both unitive unto the loadstone , and susceptive of its rayes ; and by how much more smooth and equal it superfice is made , by so many more are the parts , by which it doth touch and adhaere unto the loadstone ; and consequently imbibe so much the more of its virtue , and è contra . and this introduceth the sixth observable ; that a loadstone , being armed or capp't with steel , is thereby so much corroborated , that it will take up a farr greater weight of iron or steel , than while it remained naked or unarmed . for , mersennus had a loadstone , which , ( as himself avoucheth ) being naked , could elevate no more than half an ounce of iron ; but when he had armed it with pure and polisht steel , it would easily suspend times a greater weight , i. e. ten pounds of iron : a proportion not credible , but upon the certificate of experiment . now , the cause of this admirable corroboration of the loadstones attractive virtue , by a plate of polisht steel , can be no other than this ; that the loadstone being of such a rough contexture , as that in respect of the particles of some heterogeneous matter concorporated unto it , it is uncapable of that exquisite smoothness in the surface , which may be obtained by steel ; therefore can it not touch iron so exquisitely , or in so many points , as steel may : and consequently not invade it with so many direct and united rayes . but , steel being of a more simple substance , and close contexture ; may in all its substance be imbued with the magnetique virtue : and being polisht , touch an iron , to which it is admoved , with more parts , and invade it with more dense and united rayes . for , those indirect rayes , which otherwise the loadstone would diffuse scatteringly through the medium , in respect of the various inequalities of it superfice , and multitude of small pores intercepted among its particles ; the steel doth recollect , unite and transmit to the iron admoved , and thereby more strongly embrace and detain it . we say , to iron admoved ; for , though the retentive virtue of a loadstone armed with steel , be by many degrees stronger ; yet is its attractive virtue by some degrees weaker than that of an unarmed loadstone : i. e. it doth not diffuse its attractive virtue half so farr , and a sheet of the finest venice paper interposed betwixt an armed stone and iron , doth impede its attraction ; a manifest argument , that the fortification is determined only to contact . this we confess mersennus flatly denies , and upon his own observation : but till our reader shall meet with such a stone , as mersennus used , we advise him not to desert the common experience of the impediment of the attraction of iron by an armed loadstone , by paper interposed , since grandamicus , whose chief business was the exact observation of all magnetique apparences , expresly saith ; vix fit adhaesio ferri ad lapidem armatum , si vel charta , vel aliud tenuissimum corpus interponatur . it hath , moreover , observed , that if a magnet be perforated along its axis , and a rod of polisht steel , exactly accommodated to the perforation , be thrust thorow it ; its orb of attraction shall be much enlarged , and its energy fortified to an incredible rate . consule iacob . grandamicum , in nova demonstrat . immobilitatis terrae , ex magneticis , cap. . sect. . pag. . having layed down these sixe observables , which are of such capital concernment , as that there is no effect or phaenomenon of attraction magnetical , that may not conveniently be referred to one , or more of them ; and consigned a probable reason to each : the onely memorable difficulty that remains , concerning the attractive virtue of magnetiques , is , why a small or weak loadstone doth snatch away an iron from a great or more potent one ? but , as the incomparable kircher hath subtely observed , a small or weak loadstone doth remove a needle from a great and potent one , while it self remains within the sphere of the great or strong ones activity : because the virtue of the small or weak stone , is corroborated by the accession of that of the great or strong . which is demonstrable from hence , that if the needle be so long , that its extremes reach beyond the orb of the great loadstones activity ; then cannot a less or less potent one remove it away and elevate it : and in case one of the extremes be somewhat too near to either pole of the great loadstone , then is the less stone much less able to substract the needle than in the former case ; because so , the virtue of the great loadstone is augmented by the addition of that of the less . and hence , by way of corollary , we observe ; that the abduction of a piece of iron from the earth by a loadstone , is so farr from being a good argument against the earths being magnetique , or one vast loadstone ; that it rather makes for it : because the loadstone being applied to the iron , and operating within the sphere of the earths virtue , is so corroborated thereby , that it abduceth the iron from it , by the same reason , that a less loadstone snatcheth a needle from a great one . and thus much concerning the attractive faculty of the loadstone ; both according to the most considerable doctrine of the ancients , and the more exact theory of the moderns . sect . ii. to enquire the reason , therefore , of the other general propriepriety of magnetiques , their direction , or conversion of their poles ●o north and south ; is all the remainder of our praesent design : which that we may accomplish with as much plainness and brevity , as the quality of the argument will admit of ; we shall observe the same advantageous method of disquisition as we have done in the former , touching the causes and wayes of magnetique attraction , reducing all the observations of the moderns , of the direction , declinat●on , and inclination of the loadstone , and other magnetical bodies , to certain heads , and disposing them according to their order of subalternate dependency . the first observable is ; that the loadstone and iron are twinns in their generation , and of so great affinity in their natures , that dr. gilbert might justly say , that a loadstone is iron crude , and iron a loadstone excocted : for they are for the most part found lodged together in the same subterraneons bed ; as the experience of all such as are conversant about iron mines in germany , italy , france , england , and most other countries , doth every day demonstrate . and that i● the most probable cause , that can be given , why loadstones gene●●lly are so much the more vigorous and perfect , by how much deep●● in the veins of iron mines they are digged . there is , indeed , a re●●rt diffused not only among the people , but also some of the highest fo●● of learned writers , and chiefly derived from the authority of strabo ; that in the western ocean are certain vast magnetick ●ooks , 〈◊〉 drawing ships that sail near them ( by reason of the iron 〈◊〉 , wherewith their ribbs and plancks are fastned , and held together ) with irresistible violence and impetuosity , split them in pieces , or extracting the iron pinns , carry them like arrowes flying to a butt , through the aer : but , the light of navigation hath long since discovered this story to be as highly romantique , as the enchanted castles of our knights errant , or the most absurd of sir iohn mandevils fables ; and herein we may say of strabo , as lucian of the indian history of ctesias the cnidian , physician to artaxerxes king of persia , scripsit de ijs , quae nec ipse vidit unquam , neque ex ullius sermone audivit . the second ; that the loadstone seems not only to have all the conditions of the terrestrial globe , but also to imitate the positional respects thereof , conforming it self exactly unto it . for , as the terraqueous globe hath two poles , by which it owns a respect to the poles of the heavens , the one bor●al , the other austral : so likewise hath the loadstone two contrary poles , alwayes discoverable in the opposite parts or extremes thereof , especially if it be turned into a sphere . and , as the globe of the earth hath an aequator , parallels and meridians ; so hath the loadstone : as may be demonstrated to the eye , by applying a small steel needle thereunto ; for , at either of its poles , the needle shall be erected perpendicularly , and lye in the same line with its axis ; but at any of the intermediate spaces , or parallels , it shall be neither plainly erected , nor plainly lye along , but observe an oblique situation , and more or less oblique , according to the variety of the parallels ; and at the middle interstice , or aequator , it shall dispose it self in conformity to the ductus of the meridian , and fix in a position parallel to the axis of the loadstone . that a loadstone doth accommodate it self exactly to the earth , as a needle doth accommodate it self to the loadstone ; is evinced from this easie experiment . if you suspend a loadstone ( whose poles you have formerly discovered , and noted with the characters , n. s. ) in calme aer , or set it floating at liberty in a vessel of quicksilver , or a small skiff of cork swimming upon water , that so it may freely perform the office of its nature ; you shall observe it continually to move it self from side to side , and suffer alternate vibrations or accesses and recesses , till it hath so disposed it self according to the meridian , as that one of its poles , viz. that marked with n. shall point to the north , and the other , upon which s. is inscribed , to the south . nor that only , but , forasmuch as england is situate near the north of the earth , and so hath the north pole somewhat demersed or depressed below the horizon , nearer than the south pole of the earth : therefore doth not the loadstone keep up both its poles in a level or perfectly horizontal position , but depresseth that pole which affects the n , somewhat below the plane of the horizon , as much as it can , directing the same to the n. pole of the earth . farther , being it is commonly observed , that this depression ( some call it the declination , others the inclination ) of the n. pole of the loadstone , or point of an excited needle , is so much the greater , by how much nearer the stone or needle is brought to the boreal part of the earth ; so much less , by how much nearer to the aequator : therefore may we conclude , that a loadstone , being removed , in the same position of freedome , from the aequator by degrees to each of the earths poles , would more and more depress or decline its boreal pole , by how much it should come nearer and nearer to the boreal pole of the earth ; and on the otherside of the aequator , more and more decline its austral pole to the austral pole of the earth , by how much nearer it did approach the same ; nor could it lye with both poles above the horizon at once , in any part of the earth , but upon the aequator , and at either of the poles of the earth , the axis of the stone would make one with the axis of the earth . the third ; that iron acquireth a verticity not only from the touch or affriction of a loadstone , but also from its meer situation in , upon , or above the earth , in conformity to the poles thereof . for , all iron barrs , that have long remained in windows , grates , &c. in a position polary , or north and south ; if you suspend them in aequilibrio by lines in the aer , so as they may move themselves freely , according to the inclination of their virtue received from the earth , will make several diadroms hither and thither , and rest not untill they have converted to the north that extreme , which in their former diuturne position regarded the north , and that to the south , which formerly respected the south : and having recovered this their cognation , they shall fixe in a meridional posture as exactly as the loadstone it self , or a magnetified needle . to experiment this , the most easie way is to offer , at convenient distance , a magnetick dial , or marriners compass , to the extrems of an iron barr , that hath long layn n and s : for , then may you soon observe the needle or versory freely equilibrated therein to be drawn in that point , which respecteth the north , by that extreme of the barr , which is australized , and , on the contrary , the south point of the needle to be drawn by that extreme of the barr , which is borealized . this vertical impraegnation of iron meerly by the earth , is also evidenced from hence ; that iron barrs made red hot , and then set to cool in a meridional position , do acquire the like polary cognation , and being either at liberty of conversion suspended by small chords in the aer , or set ●loating in small boats of cork , or applyed to the needle of a pixis nautica , immediately discover the same . this being most manifest , why may not our marriners , in defect of a loadstone , make a needle or fly for their chard , of simple iron alone ; since , if it hath layn in a meridional situation above the earth , or been extinguished according to the same lawes of position , it will bear and demonstrate as strong an affection to the poles of the earth , as a needle invigorated by a loadstone , nor shall the depression or declination of the one , in each degree of remove from the aequator toward either pole , be less or greater than that of the other . the fourth ; that insomuch as both the loadstone and iron h●ve so neer a cognation to the earth , and conformity of situation to the parts of it : nothing , certainly , can seeme more consentaneous , than that they both hold one and the same nature in common with the e●rth , at le●st with the internall parts , or kernell thereo● ; but yet with th●s difference , that iron , being a part of the earth very much altered from its orginall constitution by the activity of its seminall principle , cannot therefore so easily manifest its extraction , or prove it self to be the genuine production and part thereof , without praecedent repurgation , and excitation , or fre●h an●mation from the effluviums of the earth ; but a loadstone , hav●ng not un●ergon the like mutations from concoction , and so re●aining nearer allied to the earth , doth retain a more lively t●●cture of its polary faculty , and by the evidence of spontaneous d●●●ct●on demonstrate its verticity to be purely native , and it 〈◊〉 by consequence , to be onely a divided part , or legitimate 〈◊〉 of the earth . further , from hence , that the loadstone an● the terrestriall globe have both one and the same power , th●ugh in different proportions , of impraegnating iron with a 〈◊〉 ●●●●ction , impressing one and the same faculty thereupon ; it is iust●y in●errible , that the loadstone , not onely in respect of ●ther conditions wherein it resembleth the earth , but also , and in chief of this noble efficacy of invigorating and renovating the 〈◊〉 qu●lity of iron , may well be accounted ( as the fat●e● of magnetique philosophy , dr. gilbert hath named it ) 〈◊〉 ter●●lla , the globe of earth in epitome ; and that the e●●th it self may be reputed ingens magnes , a great loadsto●e th●ugh , in truth , the earth may challenge the title or a g●eat 〈◊〉 by another right , though somewhat less evi●ent ; and th●t i● its attraction of all ●errene bodies in direct lines to it self ●as we ●ave formerly made most verisimilous , in our chapt. of gr●vity and levity ) by the same way and instrum●nts , as the l●●●stone att●●cteth iron . and though it cannot 〈◊〉 ●enied , that 〈◊〉 co●tex of the terrestriall globe , which may ●e ●●ny 〈◊〉 t●●ck , is variously interspersed with waters , 〈…〉 , stones , metalls , metalline juices , and div●rs other dissimilar and unmagneticall bodies : yet notwithstandin● may we justly conceive , that the nucleus kernell or interior part 〈◊〉 the e●●th is a substance wholly magneticall , and that many ve●ns or branches thereof , being derived unto the exterior ●●rts , are those very subterraneous veins from which by effossion lo●●stones are extracted . especially since nature doth invite us to this conception by certain clear evidences not onely in iron , which may be digged out of most places in the earth , but also in ●●st argillous and arenaceous concretions ; all which are found to be endowed with a certain , though obscure● polary inclination , as appears in bricks and tiles , that have a long time enjoyed a meridion●ll situation , regarding the n. with one extreme , and the s. with the other , or been made red hot and afterward cooled north and south , o● perpendicularly erected , as hath been said of iron barrs . the fifth ; it being then most certain , that iron obtaines a magneticall verticity , or faculty of self-direction to the poles of the earth , meerly either from its long situation , or refrigeration after ignition , in a position respective thereunto : we may be almost as certain , that this affection ariseth to the iron from no other but a locall immutation , or change of position of its insensible particles , solely and immediately caused by the magneticall aporrhaea's of the earth invading and pervading it . when we observe the fire by sensible degrees embowing or incurvating a peice of wood , held neer it , how can we better satisfy our selves concerning the cause and manner of that sensible alteration of the figure of the wood , then by conceiving , that its insensible particles are all of them so commoved by the atoms of fire immitted into it substance , as that some of them are consoc●ated which were formerly at distance , and others dissociated , which were formerly contingent , all being inverted and so changing their pristine situation , and obtaining a new position , or locall direction , much different from their former ? and , when we observe a rod of iron , freshly infected with the polary virtue of the earth , to put on a certain spontaneous inclination in its extremes , and convert it self exactly according to the meridian , and with a kind of humble homage salute that pole of its late inspirer , from whence it received the strongest influence : how can we more reasonably explain the reason of that effect , than by conceaving , that upon the immi●sion of the earths magneticall rayes into the substance of the iron , the insensible particles thereof are so commoved , distructed , inverted , and turned about , as that they all are disposed into a new posture , and acquire a new locall respect or direction ; according to which they become as it were reinnimated with a tendency , not the same way , but another much different , and ( when the cognation of their extremes are varied by an inverted ignition and refrigeration ) quite contrary to that , whither they tended before this mutation of their position and respect ▪ this conjecture may seem somewhat the more happy from hence ; that a barr of iron , when made red hot , doth acquire this polary direction in a very few minutes of time : but being kept cold ▪ it requires many years situation north and south , to its impraegnation with the like virtue ; a sufficient manifest , that the particles of the iron being , by the subingression of the atoms of fire among them , reduced to a greater laxity of contexture , are more easily commoved and inverted by , and more expeditely conforme themselves unto the disposition of the magnetique influence of the earth . when a red hot barr of iron is cooled , not in a meridian position to the poles of the earth , but transversly or equinoctionally ; why doth it not contract to it self the like verticall disposition ? doubtless , the best reason that can be given for it , is this ; that the insensible particles of it are not converted , nor their situation varied so much in the one position of the whole mass , as in the other : the magneticall rayes of the earth invading the substance of the iron in indirect and so less potent lines . likewise , if the same barr of iron , after it hath imbibed a verticity , be again heated and coold in a contrary position ; what reason can be assigned to the change of the southern verticity into a northern , and its northern into a southern , by the contrary obversion of its ends : unless this , that the particles of the iron doe thereby suffer a fresh conversion , and quite contrary disposition ; no otherwise than those of a piece of wood , when it is incurvated by the fire according as this or that side is obverted thereunto ? the sixth ; forasmuch as iron doth derive the same verticity or direction from its affriction against a loadstone ; as it doth from the magneticall influence of the earth , when posited respectively to its po●es : it appears necessary , that it doth suffer the same locall immutation of its insensible particles , from the efficacy of the magneticall rayes of the loadstone , as from those of the earth ; especially since we cannot comprehend , how a body should acquire a strong propension or tendency to a new place , without some generall immutation , and that a locall one too , of all its component particles . the strength of this our conception consisteth chiefly in this ; that after a rod or needle of iron hath contracted a sprightly verticity from a loadstone , by being rubbed thereupon from the middle toward the ends , it doth instantly lose it again , if it be rubbed upon the same , or any other loadstone , the opposite way , or from either end toward the middle . for , how can it be imagined , that a right-hand stroak of a knife upon a loadstone should destroy that polary faculty , which it had obtained from a left-hand stroak upon the same ; unless from hence , that the insensible particles of the blade of the knife , were turned one way by the former affriction , and reduced again t● their former naturall situation by the latter ? it seems to be the same , in proportion , as when the ears of corn in a field are blown toward the south by the north wind , and suddainly blown from the south toward the north by the south wind . nor doth iron , after its excitement retain any of the magneticall atoms immitted into it either from the earth , or a magnet ; but , suffers only an immutation of its insensible particles , which sufficeth to its polary respect a long time after : for , a needle is no whit heavier after its invigoration by a loadstone , than before , as mersennus and gassendus together experimented , in such a zygostata or ballance , wherewith jewellers are to weigh pearles and diamonds ; which is so exact , that the ninety-sixth part above four thousand of a grain , will turn it either way . the seventh ; that the virtue immitted into iron , either from the earth it self , or a loadstone , is no simple , or immateriall quality , as both gilbert and grandamicus earnestly contend ; but a certain corporeal efflux , or fluor , consisting of insensible bodies , or particles , which introduce upon the particles of iron the same disposition , and local respect , as themselves have . for ( ) that an immutation is caused in the particles of iron , as well by the influence , or magnetical rayes of the loadstone ( which doth also invigorate iron , at some distance , though not so powerfully , as by immediate contact , or affriction ) as of those transmitted from the earth ; we have already declared to be not only verisimilous , but absolutely necessary : & that nothing should yet be derived unto the iron from them ; as the instrument of that immutation ; is openly repugnant to the fundamental laws of all physical activity , since nothing can act upon a distant subject but by some instrument , either continued or transmitted . ( ) what is immitted into the iron from the earth and loadstone , cannot be any naked ●uality , or accident without substance ; because , what wants substance , must also want all activity . ( ) the materiality of the magnetique virtue is inferrible likewise from hence , that it decayes in progress of time ( as all odours do ) and is irreparably destroyed by fire , in a few minutes , and is capable of rarity and density ●whence it is more potent near at hand , than at the extremes of it sphere ) all which are the proper and incommunicable attributes of corporiety . ( ) insomuch as it changeth the particles of iron , that have figure and situation ; therefore must it self consist of particles also , and such as are in figure and situ●tion consimilar to those of iron : no less being assumable from the effect even now mentioned , viz. the ablation of that verticity , by a right hand draught of a needle upon a loadstone , which it lately acquired from it , by a left hand one . nor , indeed , doth the loadstone seem to act upon iron , otherwise than as a comb doth upon wool or hair ; for as a comb being drawn through wool , one way , doth convert and dispose the hairs thereof accordingly , and drawn praeposterously or the contrary way , doth invert & praeposter the former ductus of the hairs : so do the magnetical rayes invading and pervading the substance of iron , one way , dispose all the insensible particles thereof according to their own ductus , toward the same way ; and immitted into it the quite contrary way , they reduce the particles to their native situation and local respect ; and so the formerly imprinted verticity comes to be wholly obliterated . objected , we confess it may be ; that the incorporiety , or immateriality of the loadstones virtue seems inferrible from hence , that it most expeditely penetrateth and passeth through many bodies of eminent solidity , and especial marble : ( ) that it is ( soul-like ) total in the total loadstone , and total in every part thereof : seeing that into how many sensible pieces soever a loadstone is broken or cut , yet still doth the virtue remain entire in every one of those pieces , and there instantly spring up in each single fragment , two contrary poles , an axis , aequator , meridians and parallels . but , as to the subtility of particles and pores in concretions , our book is even surcharged with discourses upon that subject , in the generall : ●o that notwithstanding the first objection , we may adhaere to our former conception , that the particles flowing from the earth and loadstone , are of such superlative tenuity , as without impediment to penetrate and permeate the most compact and solid concretions , and specially marble , whose small pores may be more accommodate to the figures of the magnetick atoms , and so more fit for their transmission , than those of divers other bodies much inferior to it in compactness and solidity . and being we have the oath of our sense , that the atoms of fire doe instantly find out many inlets or pores in the body of marble , by which they insinuate themselves into its centrall parts , and so not only calefie the whole mass or substance thereof , but reduce it suddainly into a brittle calx : why should we not concede , that the magnetick atoms may likewise find out convenient inlets or pores in the same , and by them nimbly pervade the whole mass ; and that with so much more of ease and expe●ition , by how much more subtile and active they are , than those of ●ire ? true it is , that we can discerne no such particles flowing from magneticks , no such pores in marble , but how great the dulness or grosness of our senses is , comparatively to the ineffable subtility of many of natures instruments , by which she bringeth admirable effects to pass , we need not here rehearse . ( ) as for the other argument desumed from the f●ustulation of a loadstone , we answer ; th●t the single virtues of the single fragments , are nothing else but so many parts of the totall virtue : nor being taken singularly , are they equally potent with the whole ; only they are like the totall , because in the whole loadstone they follow the ductus or tract of its fibres , that run parallel each to other , and conjoyn their forces with th●t fibre , which being in the middle , stands for the axis to all the rest . but , in each fragment , they follow the same ductus or grain of the f●bres , and one fibre must still be in the middle : which becomes an axis , and that to which all the circumstant ones confer and unite their forces . the eighth ; that the magnetick virtue , both existent in the loadstone , and transfused into iron , seems by a lively analogy , to resemble the vegetative faculty or soul of a plant ; not only in respect of the corroboration of the force of its median fibre , or axis , by the con●erence of the forces of all the circumstant ones thereupon , as the centrall parts of a plant are corroborated by the circumambient : but also , and principally , in respect of the situation , ductus , or grain of its fibres ; which run meridio●ally , as those in plants perpendicularly , or upward from the roots to the tops of the spriggs . for , as in the incision or engr●ffing of the shoot of one tree , into the trunck or stock of another , the gardiner must observe to insert the lower extreme of the shoot , into a cleft in the upper extreme of the stock , as that from whence the nutritive sap and vegetative influence are to be derived unto it ; because , if the shoot were inverted , and its upper extreme inserted into the stock , it would necessarily wither and die , as being in that praeposterous position made uncapable of the influx of the alimentary juice and vitall faculty , both which come from the root upward to the branches , and cannot descend again from them to the root : exactly so , when we would dispose a loadstone in conformity of situation to the earth , from which it hath been cut off , or to another loadstone , a quondam part of it self ; 't is not every way of apposition , that will be convenient , but only that , when it is disposed in a direct line , respondent to the same ductus or situation of its fibres , according to which it was continued to the earth , be●ore its separation . nor is this meer conjecture , but a truth as firme as the earth it self , and as plain as sense can make it ; it being const●ntly observed , that what situation a loadstone had in its matrix , or minerall bed , the very same it shall strongly affect , and strictly observe ev●r after , at least , while it is a loadstone , i. e. untill time or fire have destroyed its verticity . and , as for the use thereof ; it is so ●ruitfull , as to yield us the most probable reason in generall , for sundry the most obscure among all magneticall apparences . ( ) forasmuch as the loadstone ever affects its native situation , and that its northern part did , while it remained in its matrix , adhaere to the southern parts of the same magnetique vein , that lay more north , and its southern part did adhaere to the northern part of the magnetick vein , that lay more south : therefore is it , that the north pole of a loadstone doth never affect an union with the north pole of the earth , nor its south pole direct to the south pole of the earth ; but quite contrary , its north pole converts to the south , and its south to the north. so that whenever you observe a loadstone , freely swimming in a boate of cork , to convert or decline one of its poles to the north of the earth ; you may assure your self , that that is the south pole of the loadstone : and è contra . ( ) from the same and no other cause is it also , that when a magnet is dissected or broken into two pieces , and so two new poles created in each piece ; the boreall pole of the one half shall never admit coition with the boreall pole of the other , nor the australl extreme of the one fragment affect conjunction w●th the australl extreme of the the other : but contrariwise , the australl end shall septentrionate , and the septentriona●● australize . the same also happens , whenever ●ny two lo●●stones 〈◊〉 applied each to other ; the cause being generall , viz. the native 〈◊〉 or grain of the magnetique fibres : which is inverted , whene●●● the boreall part of a loadstone is applied to the boreall pa●t of the earth , or of another loadstone ; or the meridionall part of a loa●st●ne be converted to the meridionall part of the earth of another loadstone ; as the ductus of the fibres in a shoot of a pl●nt is inverte● , when the upper extreme thereof is inserted into the upper part of a s●o●k . this considered , when we observe the animated needle 〈…〉 mariners compass , freely converting it self round , upon the pin , ●hereon it is aequilibrated ; that end , which directeth to the nor●● pole of the earth , must be the south point of the needle , and viceversally , that must be the north cuspis of the needle , which con●rontet● the south of the earth . and , when praesent a loadstone to a magnetified versory , that part of the loadstone must be the north pole , to which the south cuspis of the needle comes ; and that , to which the north point of the needle approaches , must be the south of the loadstone . the same also may be concluded , of the extremes of irons , when a loadstone is applied unto them ; for , that part of an iron barr , which laied meridionally , hath respected the north , must have been spirited by the southern influence of the earth ; and è contra : and among our fire irons , the upper end must have imbibed the northern influence of the earth , and the lower the southern ; contrary to the assertion of some of our magneticall philosophers . the ninth ; the analogy of the earth to the loadstone , and other magnetically inspired bodies , being so great , and the cause thereof so little obscure ; it may seem a justifiable inference , that the terriestriall globe doth inwardly consist of certain continued fibres , running along from north to south , or from south to north , in one uninterrupted ductus : and consequently , that since the middle fibre is as it were the axis , whose opposite extremes make the two poles , in case the whole earth could be divided into two or more great parts , there would instantly result in every part or division , a special axis , two speciall poles , a speciall aequator , and all other conditions as formerly in the whole globe ; so that the septentrionall part of one piece would conjoin it self to the austrine part of another , and the septentrionall parts reciprocally avert themselves each from other , as the parts of a loadstone . and this we may understand to be that mighty and so long enquired cause , why all the parts of the terrestriall globe do so fi●mly cohae●e , and conserve the primitive figure ; the cohaesion , attractive virtue , constant direction , and spontaneous verticity of all its genuine parts , all whose southern fibres doe magnetically , or individually conforme and conjoyn themselves to the northern , and their northern to the southern , being the necessary causes of that firmness , and constancy of figure . impossible , we confess , it is , to obtain any ocular experiment of this constitution of the earths internall fibres ; the very cortex of the earth extending some miles in profundity : but yet we desume a reasonable conjecture thereof , as well from the great similitude of effects wrought by the earth and other magneticks , as the experience of miners , who frequently observe , and constantly affirme , that the veins of subterraneous rocks , from whose chinks they dig iron oare , doe allwayes tend from south to north ; and that the veins of eminent rocks , which make the giant mountains upon the face of the earth , have generally the same direction . and though there are some rowes or tracts of mountains , that run from east to west , or are of oblique situation ; yet are there alwayes some considerable intercisures among them , from south to north : so that that can be no sufficient argument , that the interior fibres of the earth , which are truely and entirely magneticall , and subjacent under those mountainous rocks , doe not lye in a meridionall position , or conforme to the axis of the earth . the tenth ; that since the observations of miners ascertain us , that the ranges or tracts of rocks , in the cortex or accessible part of the terrestriall globe , do for the most observe a praecisely meridionall situation , and tend from south to north , and sometimes ( i. e. in some places ) de●lect toward the east and west , with less and greater obliquity ; and that our reason may from thence , and the similitude of the e●rth and loadstone , naturally extract a conjecture , that the fibres of the earths kernell or inaccessible parts , though for the most they tend praecisely from the south to the north ; may yet in many places more and l●ss deflect toward the east and west : we need no longer perplex ou● minds with enquiring , why all magnetiques , and especially the versory or needle of the sea-mans compass , being horizontally aequilibrated , do● in some places point directly to the north and south , and in others deflect toward the east and west , with more and less of obliquity ; which navigators call ( for distinction of it from the depression , or inclination , formerly explicated ) the variation of the l●adstone , or needle . from the mariners tables ( though they are 〈◊〉 of discord , as to the degrees of the needles deflection or variation from the true meridian , in severall parts of the earth ) we learn , that the needle doth exactly conforme it self to the axis of its great ●●●pirer ▪ the earth , without any sensible deflection at all , in the iland corvus , one of the azores , in the iland of the trinity , in the pro●●●tory of the needles , neer the cape of good-hope , in the 〈◊〉 hercul●um , syllaeum , the thracian bosphorus , the 〈…〉 vienna , and divers other places . but in others , 〈…〉 england , it 〈◊〉 somewhat toward the e●st , yet 〈…〉 , so th●t in some countries its variation exceeds not . . or ● ▪ degrees at most , and in others it amounts to n● less than , ●r ● ▪ again there are other meridians , in which the declination of the ●●mpass is toward the west ; as frequently upon the orien●all 〈◊〉 of 〈◊〉 northern america ; on the occident●ll coast of nova z●●b●a , an goa ; the eastern side of africa ; in our mediterrane , at naples , 〈◊〉 sundry other places . nay , oftentimes in the same meridian , and in 〈◊〉 degrees of latitude , it hath been observed , that the needle 〈◊〉 not vary at all , and vary both eastward and westward ▪ for , though in the iland corvus the declination be insensible , where the l●titude is of about degrees ; yet on this side of it , in the latitude of degrees ●he declination amounts to degrees eastward : and beyond it , in the latitude of degrees the declination toward the west , ariseth to degrees ; and farther off , in the latitude of the westward declin●●●on equalls degrees . so also , in the iland e●ba , at one promonto●● ▪ the needle deviates toward the east on●y degrees ; at another prom●●●ory , ; and at a third , as high as . which being duely perpended , ●oth soon detect the unadvisedness and incircumspection of those , 〈◊〉 have referred the declination of the m●gnet to the deviation of the asterisme , ursa minor , or pole of the ecliptick from the poles of the world ; and attempted to explain it by imagining some certain magnetick rocks , which being situate on the east side of the 〈◊〉 pole of the earth , constitute a speciall magnetick pole , 〈…〉 the versory needle is generally deflected . much more 〈…〉 was the invention of dr. gilbert ; who supposing that the 〈◊〉 virtue of the earth was more powerfully impressed upon 〈…〉 from the extant or eminent parts thereof , and especially 〈…〉 continents : makes out the cause of the magnets indirection , or variation , thus . if the needle be placed in the middle betwixt two vast continents , as in the azores , which have europe to the east , and america to the west ; it suffers no sensible distraction to either part : but , if it be brought nearer to the continent of europe and asia , it must be invited and deflected toward the east ; and nearer to the continent of america , it shall deviate as much toward the west . for the same cause also , upon the western coast of africa the declination is toward the east ; and on the orientall , toward the west : and betwixt them both , as at the cape of good-hope none at all . and yet this subtle theory of dr. gilbert is more the● suspected of imperfection . for , since that , on the western coast of america , and of goa , the declination of the needle is westward ; and not onely on the orientall side of the meridionall america , and chiefly about the streights of megellan , but also on the orientall side of the septentrionall america , as at virginia , the declination teaseth not to be , in the same manner , toward the east ; absolutely contrary to his hypothesis : therefore hath the incomparable father , kircher , to his own immortall honour , and our greater satisfaction , advised us , to leave the attraction of adjacent continents , and have recourse onely to the divers positions of the interior magneticall fibres of the earth , over which the magnet , or needle stands ; considering that they have their situation sometimes exquisitely meridionall , sometimes more and less oblique , and tend in some places in longer , in others in shorter tracts . for , it is no difficult conception , the virtue of the earth is impressed upon the needle from the magneticall fibres and veins , that are nearest , i. e. directly subjacent thereunto ; and disposed thereby into a situation respective to the ductus of those perpendicularly subjacent fibres : so that whatever be the direction of the needle ; i. e. either without all declination , or with some , more or less , in one part toward the east , in another toward the contrary pole of the heavens ; still may we suppose it to be exactly respondent to the ductus , or direction of the fibres of the earth , that perpendicularly lye underneath it . nor is this meerly petitionary , or excogitated onely for the solution of this grand magneticall problem , as the former of gilbert seems to have been ; but founded upon a parallel experiment : for , if you place severall barrs of iron excited , upon the ground , so that one may lye exactly according to the meridian , and all the rest in severall degrees of obliquity , untill you come almost to make an aequinoctionall line with one ; and then gently and at requisite distance , move an invigorated needle , equilibrated upon a pin , over them ; you shall observe the direction of it to be varied to more and less obliquity from the meridian barr , respectively to the situation of each of the other barrs , over which it is directly held . now , if you suppose the magnetique fibres of the earth to have the same virtue upon the needle , as , if not much more than the subjacent iron barrs have : you have attained the bottome of the mystery , and that one of the greatest in nature . the eleventh and last ; that as the conversion of the inspired needle is no● exactly meridionall in all places of the earth , but siding more or less ●oward the east , in some topicall meridians , and toward the west , in others : so also is not the declination thereof , though in one and the same place , constant to the same degree , at all times , but admits considerable variation , and that in a few years . for , mr. burrow● , in the year , making an exact observation of the quantity of the needles declination toward the east , at limus , near london , found it to amount to no less than . degrees minutes : and afterward , in the year . mr. gunter , at the same place , observed it to be diminished to onely . degrees , and minutes : and gellebrand , in anno dom. . in the same place , found it to come yet lower , and not to exceed degrees minutes : so that , in the meridian o● london , as our noble countryman , sir. ke●elm digby hath w●ll remarked , the declination of the needle eastward hath been mo●● diminished in the latter years than in the former . the like de●●●ase of the variation of the needle hath been taken notice of also in france , at paris by mercennus , and at aix , by gassendus . and therefore we may praesume , if the needles continue , in the same manner , and at the same rate , to lessen their declination , that within a very few years , with us here in england , and other adjacent countries , they will have no declination at all toward the east , and perhaps wheele about toward the west , and every year more and 〈◊〉 approach the contrary point of the aequator . now , as for th● cause of this truely stupendious effect of magneticks ; grandamicus , indeed , thinks it best solved , by charging it onely upon the e●●ors of observation , not upon any mutation of the axis of the e●rth , which would of necessity vary all caelestiall observations , no ●●ss than magneticall ones : enforcing this his opinion from hen●● ▪ that the best of astronomers are frequently not onely subject to ▪ but guilty of great errors , in their operations to find out the true generall meridian line , of the altitude of the sun , of the poin● of the heavens that is verticall to this or that place , where they use their instruments , the certain knowledge of all these particulars being absolutely requisite to make a true compute of the degrees of the needles variation . but , the observators nominated being all eminent mathematicians , well understanding the seve●●ll causes , that might betray them into in●ertitude , and aswell how to praevent or avoyd them all ; and each one setting about the work , with all possible care and circumspection : and it being very improbable , that they all should fall into one and the same delusion : th● ingenious , we hope , will excuse us , if we incriminate ●randami●●● himself , with much of temerity , and somewhat of injustice , 〈…〉 detractring judgement of his ; and assent to their more 〈◊〉 and reasonable one , who referr this sensible declination of dec●●●●tion in the magnet , to some certain indigenary cause , or dispo●●●●on proper to those places and countries , where such observation ●ere made . but , what indigenary and particular disposition th●● 〈◊〉 , which should thus vary the magneticall variation , in the 〈◊〉 of a few years ; is a problem indeed , and such as seems reserved ●or the exposion of elias . kircher and gassendus , we acknowledge , have attempted most laudably , in supposing the magneticall fibres , that lye more distant from the axis of the earth , or neerer to the superfice thereof , not to be so firmely cohaerent each to other , but that they may be emoved , evolved , and separated , by some subterraneous cause or other , and so exchange their more oblique , for a less oblique , and at length for an absolutely direct or truely meridionall situation ; as the fibres of the muscles of animalls are observed sometimes to suffer a certain revulsion , or change of situation , under the skin , for severall causes : and that this locomotion and decrement of obliquity of the superficiall magnetick fibres of the earth , may be the sole cause of the like decrement of obliquity , or declination of the needle , in one and the same place , in divers years . but , forasmuch as this supposition is irreconcileable to our ninth observable praecedent , touching the cause of the firme cohaesion of the parts of the earth , and the constancy of its sphaericall figure , from thence resulting ; and that neither kircher nor gassendus tells us , what subterraneous cause that should be , which might emove and translate the magneticall fibres of the cortex of the earth , from a more to a less indirect situation ( which in justice they both ought to have done : ) we shall onely applaud the ingenuity of their conjecture , and return to our former judgement , that the true cause of the decrement of the magneticall variation is yet in the bottome of democritus pit ; and he , who shall be so happy to extract it from thence , shall have our vote , to have his statue set on the right hand of that of gilbert , in the vatican . there ye● remains a difficulty , which being left unresolved , is of importance enough to make the intelligent and wary reader somewhat costive in his assent even to the chiefest and most fundamentall of our praecedent observables , concerning the reason of magneticall verticity . and that is , that some loadstones have more than two poles ▪ such as that tripolar one of furnerius , of which both kircher and gassendus make singular mention . concerning this , therefore , we say ; that in every loadstone there are two , and but two true and legitimate poles : and that all others apparent in them , either at the aequator , or betwixt it and either of the genuine poles , are spurious or illegitimate ; arising either from some node or knot growing laterally on to a magnet ( such as is commonly observed to interrupt the direct progress of the fibres , or grain of trees , and of stones ) or from an irregular and horned figure of the stone it self , in respect of either of which the magnetick virtue cannot be commodiously united at the two genuine and directly opposite poles , but is distracted obliquely to that prominent node , or horn-like protuberancy . for , if either the node or horns of a loadstone , which cause it to have more than two poles , be artificially cut off , and the remainder of the stone be polished ; a needle , or the filings of steel , thereunto applied , shall never be perpendicular erected at any part thereof , but onely at the artick and antarctick points ; nor shall the stone dispose it self otherwise than conformably to the meridian ▪ both which are the most c●rtain discoverers of the true poles of a loadstone . those illegitimate poles , therefore which sometimes ( though very rarely ) are found in a loa●stone , are as it were the oblique and pr●eternaturall parts of it , obtaining the reason of poles only by accident . which yet hinders not , but that m●ny times , from the imperfection of the stone , it may come to pass , that the two legitim●te poles of the same loadstone , though ●xactly polished , and reduced to a perfect sphere , may not exist in th● ext●emes of its diametre ▪ for , unleses the magnet be uniforme in subst●nce and virtue , the poles thereof cannot be directly opposite each to other . and thus , in a naturall method , and with as much succinctness , as the copious subject woul● be●re ( according to our engagement● have we enquired into the cau●● of the two generall faculties of the loadstone , the 〈◊〉 and 〈◊〉 with the most considerable phaenomena's arising from either , or both of them . wherein , if we have been so happy , as to afford but the l●●st of satisfaction to others ; we shall account it no small 〈◊〉 to ourselves , and think our studies thereby more th●n sufficien●●● compensated . if not , we shall yet consolate ourselves with this 〈◊〉 we are not the first , who have fallen short of the readers expectati●●●●n the discussion of this singularly abstruse argument : which is a thing so highly admirable , that aphrodisaeus ( initio pro●lem . ) affirmed ●he nature thereof to be understood only by him , that created it ; and ●alen de therica ad pison . ) termed the attractive virtue thereof wh●● divine . to which we shall add also this ; that the hypothesis , of th●●ontinued ductus of the magnetick fibres of the earth , especially 〈◊〉 the kernell , or interior substance thereof , from the south to the north pole ●upon which we have erected the solutions of sundry great magne●●call apparences ) is subject to much less of improbability , than that o● ●ilbert and grandamicus , that the magnetique virtue is a simple , or imma●●●iall quality ; than that of de's cartes , that the magnetique aporrhaea's consist of streated or screw'd atoms , passing through the earth , by contr●●● and diversly figurated insensible pores , issuing forth at either po●e , and ●●eeling about interchangeably to the opposite pole ; than that of sr. 〈◊〉 digby , that the magnetique streams glide along from either pole an● hemisphere of the earth , by attraction to the aequator ▪ or , in truth ●●an any other hitherto excogitated and divulged . but ▪ before we pu● an end to this chapter ; 't is requisite to advertise you o● a confider●●●● ▪ omitted in the beginning of it ; which is , th●● though we 〈◊〉 the virtue magnetick to be ( in generall ) two-fold ▪ attractive 〈◊〉 directive ; yet is that distinction to be admitted , no● in an absolute 〈◊〉 respective intention , or only ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) in order to our mor●●●stinct comprehension of the immediate ; and particu●ar reasons of 〈◊〉 respective magneticall effects , which ot●erwise must have wanted 〈◊〉 advantage of order in their consideration . for , we are fully 〈◊〉 of the truth of that assertion of grandamicus ( nova demonstra●●●●mobilit . terrae ▪ cap . sect. . ) that the attraction and dire●●ion or 〈◊〉 and polarity of magneticks , are caused by one and the sam● 〈◊〉 which being conferred upon them , by the infinite wisdome and 〈◊〉 of the creator , in order to the conservation of the earth , and all its genuine parts , in that position in the universe , and that disposition among themselves , in which they are best supported , and most conveniently performe actions conforme and proper to their nature ; may be yet termed attractive , insomuch as it unites magneticall bodies , violently separated ; and directive , insomuch as it disposeth them in a due and commodious situation . and so , notwithstanding the actions and motions of magnetiques seem exceeding various , and in some cases , plainly contrary ; yet are they to be deduced from one simple principle , one and the same generall virtue , and they all may be conveniently explic●ted by the same common reason . the fourth book . chap. . of generation and coruption . sect . i. that nature , or the common harmony of the world , is continued by changes , or the vicissitudes of individualls , i. e. the production of some , & destruction of other things , determined to this or that particular species ; and that there must be one catholique matter , of which all things are elemented , and into which they may be again , by dissolution , reduced : are positions , to which all men most readily prostrate their assent . but , what that first and common matter is ; how concretio●s are educible out of it ; and how reducible at length into it , after the privation of their specificall formes : are quaestions , whose beginnings are more easily known , than their ends . however , forasmuch as we have endeavoured , in our immediately foregoing book , to determine the first of them , together with the possible emergency of all qualities ( whereof either our sense , or reason can afford us any measure of cognizance ) and the reasons of the perception of them by animals , from atoms , so and so configurated , and so and so disposed in commistion : it now neerly concerns us , to attempt the most hopefull decision of the other two that so we may not seem to have thus long discoursed of the principles , and affections of compound bodies , while we remained wholly ignorant of the most probable wayes both of their origination from those principles , and of their reversio● into them again , when they have lost the right of their former denominations , and suffered to the utmost of their divisibility . by the terme , generation , we ought praecisely to understand that act of nature , whereby she produceth a thing de novo , or gives being to a thing , in some certain genus of bodies concrete : and consequently , by its contrary , corruption , that whereby she dissolves a thing ▪ so that thenceforth it ceaseth to be what it was . for , when fire , a stone , a plant , an animal , or whatever is referrible to any one determinate kind of bodies compound , is first produced , or made , and begins to be so , or so denominated ; it is truely said to be generated : and contrariwise , when a thing perisheth , and loseth the right of its former denomination ; it is as truely said to be corrupted . and this is that which aristotle ( . de generat . ) frequently call's generatio 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , generation simple and perfect ; so to praevent that confusion of generation with alteration , into which many of his praedecessors had oft●● fallen , to their own and their disciples no little disquiet . for , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , alteration can be accounted a generation only improperly , of secundum quid ; forasmuch as by alteration a body is not produced de novo , but onely acquires some new quality , or some accidentary denomination : and philosophers accordingly define it to be progressionem corporis ex una qualitate in aliam , a progression of a body from one quality to another , as when water is changed from cold to hot by fire . again , every mutation requires a subject to be altered ; and that subject must be something compound , complete , and already constituted in some determinate genus of beings : but , of generation strictly accepted the onely subject is the first and universall matter , which being in it self destitute of all form aristole doth therefore subtly call simpliciter non-ens , simply , or determinately nothing ; forasmuch as he frequently inculteth , that generation is made [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ▪ ] ex n●n ente simpliciter . because had he ommitted that adverb simpliciter , his reader might justly have understood non ens absolute nothing absolutely ; and so have accused him of openly contradicting his own fundamentall axiome , ex nihilo nihil fieri , that nothing can be made or ●enerated of nothing . this being praemised , to praevent the danger of aequivocation ; we observe first , with aristotle ( . de caelo . ) that among the ancient philosophers , some held , that nothing is generated , nothing corrupted ; as parmenides and melissus : others again , that . all things are generated and corrupted ; as hesiod and heraclitus . secondly , that of those , who admitted generation , and consequently corruption , some conceived , that generation is made by the access of a form to matter ; and that that form is a certain new substance , absolutely distinct from that of the matter , and together with it constituting the compositum , or whole resulting from the commistion of matter and form : of which sect aristotle himself deserves to be in the chair , because in order to his assertion of this opinion , he supposeth a threefold substance , the matter , form , and composiitum arising from their commistion . but , others though they concede , that generation , indeed , consisteth in the accession of a form to matter ; yet will they not allow that form ac●eding , to be substantiall , but onely a certain accident or modification of the matter it self : so that according to their theory , in generation there superveneth upon matter some certain quality , of such a condition , as that by reason thereof a thing obtain s a certain being in nature , and acquireth some determinate denomination , respective to that genus of bodies , to which its nature doth referre it . and in the catalogue of philosophers of this persuasion , aristotle nominateth as principalls , empedocles , anaxagoras , democritus , and leucippus ; all which he sharply taxeth of confounding generation with alteration , and of inferring , that aswell generation as corruption ariseth , not from the transmutation of principles , but onely from their [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] concretion and secretion : which is not only inconsistent , but contrapugnant to his own great hypothesis , that the four elements , or catholique principles of generation , are so transmutable , both secundum substantiam ( at least , according to the comments of all his modern expositors ) & secundum qualitate● , as to their substance and qualities , as that from their commistion , alteration , and corruption , a certain new and distinct substance doth arise , which is the form of the thing so produced . for , having supposed for a groundwork , that the four elements are not the first principles ; it could not stand with his advantage , not to have assumed also , that the elements may be so transmuted , as that the more generall and common matter doth still remaine : and that the same , upon the perdition of the elementary forms , may put on a new forme , that is substantiall ; and that very thing , by which the resulting or generated body is specified , and entituled to such a denomination . but , as for empedocles , and the rest enumerated ( to whom we may add also epicurus ) 't is well known that notwithstanding they all admitted the four vulgar elements , as readily as aristotle himself , yet would they by no means hear of their transmutability either as to substance , or qualities : unanimously decreeing , that in their commistion each of them is divided into particles most minute , which yet retain the very same substance and qualities , that they had before , as that every particle of fire doth still retain the substance and quality of fire , namely heat ; and that every particle of water doth likewise constantly conserve the substance , and quality of water , viz. moisture ; and so of the other two : so that it is most evident , they would have , that in generation there is onely a [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] concretion of the insensible particles of the the elements , but no transmutation of any one of them , either with the perdition of their own , or the adeption of a new substantiall forme ; both which are praesumed by aristotle . but this great difficulty , about the generation of things from the commistion of the general principles , soon loseth it self in a greater , which concerns the manner and condition of their commistion , and whose consideration will best instruct us aswell what is the main difference among philosophers , touching this most weighty theorem , as what opinion can best deserve our approbation and assent . concerning this , therefore , we find two necessary remarks ( ) that there are two different kinds of commistion , whereof the one is , by aristotle ( de generat . . cap. . ) termed 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , composition , and by others , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , apposition : the other is called , in the dialect of the stoicks , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 confusion , and in that of galen , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , coalition , or temperation . the former is when those things , whether elements , or others , that are mixed together , do not interchangeably penetrate each others parts , so as to be conjoyned per minima ; but either themselves in the whole , or their parts , onely touch each other superficially : as in the commistion of the grains of wheat , barly , rye and other corn. the latter , when the things commixed , are so seemingly united , and concorporated , as that they may be conceived mutually and totally to pervade and penetrate each other , per minimas partes , so as that there is no one insensible particle of the whole mixture , which hath not a share of every ingredient ; as when wine and water ( that we may use the example , aswell as conception of aristotle ) are infused together into the same vessel . now the stoicks and aristotle are equally earnest to have this latter way , or manner of commistion , viz. 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , confusion , to be that , according to which the elements of principles of bodies are commix't in generation : but empedocles , anaxagoras , democritus , epicurus , with all their sectators , allow none but the former , or 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , apposition ; with very solid arguments ( among which the easy separability of wine from water , either by a sponge , or cup of ivie , is not the least ) asserting , that the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 of elements , as also of all other things , is really a meer 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , composition of their small particles , though apparently , or according to the judgement of sense , it may pass for a 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or confusion . ( ) that , when either the elements themselves , or any other bodies more concrete , as water and wine , are mixed together ; they may reciprocally divide , dissect , and resolve each other into either very small and insensible [ moleculae ] masses , which yet are each of them composed of multitudes of atoms concreted ; or most exile particles , i. e. atoms themselves : and where the resolution is only into insensible masses , there may the commistion be accounted perfect ; but , where the parts of each ingredient are so far resolved , as to be reduced quite down to the first matter , atoms , there is the commistion most perfect . now , upon this distinction depends the whole controversy betwixt aristotle and the stoicks , on one part , and the atomists , on the other , about the manner of the commistion of the common principles in generation : those vehemently contending for their totall concorporation , or unition per minimas partes , so that every the most minute particle in the whole mistum , must be of the very same nature with the whole ; these strongly asserting , that no mistion of elements , or temperation of principles , goes further than a meer apposition , or superficiall contingency of their several particles , so that the particles of each ingredient must still retain the very same nature they had before commistion , howbeit they may seem to be totally concorported , or confused , in regard they are reduced to such exility , as that each single one escapes the discernment of the sense . these two ●o highly repugnant opinions being thus rightly stated , it follows , that we uprightly perpend the verisimility of each ; that so we may confer our assent upon the more ponderous . if we look no further than the commmon notion , or what every man understands by the terme , mistion ; it is most evident , that the things commixed ought to remain in the mistum ; for if they do not remain , but perish , both according to substance and qualities , as aristotle and the stoicks hold , then is it no mistion but a destruction : and since the propriety of this notion cannot be solved by any other reason , but that of the atomists , that the particles of things are in commistion onely apposed each to other , without amission of their proper natures ; what consequence can be more naturall and clear than this , that that their opinion is most worthy our assent and assertion ? ( ) though chrysippus attempts to conserve the integrity of this common notion , by a sub●lety , saying ; that the most minute particles of things mixe● , do so remain entire both as to substance and qualities , as that they reciprocally penetrate each other , and become mutually coextended ; and that thence it comes to pass , that in the whole mistum there is none the smallest particle , which is not mixed , or which doth not partake aswell of the substance , as qualities of every ingredient 〈◊〉 ▪ ●et doth he not onely fall short of his designe , but also further en●ang●e himself , and subvert other more manifest notions . for , f●●m that his position it necessary follows . ( ) that two bodies are at once in one and the same place , both mutually penetrating each others dimensions , or without reciprocall expulsion ( ) that a pint of water , and a pint of wine commixed , must not fill a quart , but that both are no greater than one , i. e. be both contained in a pint together : forasmuch as it supposeth , that the particles of one have no other ubi , but what is posse'st by the particles of the other . ( ) that a very small body may be coextensive , or coaequate to a very great one ; as that a spoonfull of water may be coaequate to a but of wine : since it supposeth , that , both being commix't , there is no part of space in the vessel including them , which doth not contain somewhat of the water as well as of the wine . now , all these things being manifestly repugnant , and yet naturally consequent upon chrysippus position : it is no less repugnant , that the particles of things commixt should remain , by mutuall penetration , and coe●●ension . ( ) nor , indeed , hath aristotle himself been more happy than chrysippus , in his invention of a way , to remove or palliate the gross repugnancy of his opinion , to the proper importance of the term , commistion ; as may easily be evinced by a short adduction of it to the test of reason . that he might defend his doctrine of the remanence of things commixed , notwithstanding their reciprocall transubstantiation ; and at the same time avoid ●hose sundry manifest 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , or incongruities , to which that doctrine 〈◊〉 subject : he excogitated two sophisticall subter●uges . the one , that when two divers things are commixed , in very unequall proportions , so as the one is very much praevalent o're the other ( as when one single ●rop of wine is instilled into ten thousand gallons of water ) in th●● case there is no mistion , in strick acceptation ; but an absolute ex●olution and transmutation of the species of the weaker into that of the stronger , ( of the species of the wine , into that of the water . ) the other , that when the things commixed are so exactly equall in qu●●●ity or virtues , as that one is not the least praevalent over the other ; o● when the one praevails upon the other but little : in both these cases ▪ though each put on the nature of the other , by reciprocall t●ansmuta●●on , or that which is a little inferior be altered from its own nature into that of the superior ; yet is not that transmutation of both , a generation of either , or the transmutation of the one , a generation of the other ▪ but onely of some third thing , which is middle betwixt , and common●o ●o both . but ▪ there is neit●er of these , which may not be called a snare , more justly than a subter●●●● . for , as to the first ; were he living , and in the schools , we sh●●ld onely demand of him , if after the instillation of one single drop of wine into gallons of water , a second drop should be supe●●nfused , and after that a third , a fourth , and so more and more successively ▪ till the mass of water were augmented to ten , a hundred , a thousa●●fold : of what nature would the whole mixture of wine and water be ? he , doubtless , would answer us , that the whole would still b● water , though to one measure of water measures of wine were superaffused drop after drop ; since , according to his own theory ▪ it allwayes must remain meer and simple water ( other●●●● the first ●●op of wine could not be transpecificated , or be converted into the ●●ture of the water ) into which even the very last drop of wine wa●●●●used : or else he must teach us when , i. e. from what particular drop of wine instilled , the whole aggregate or mass of both l●quo●● beg●●●o put off the nature of water , and on that of wine . and , who is so 〈◊〉 ●ither by nature , or praejudice , as not to apprehend , that the re●son is 〈◊〉 same for one , as for the other ; for ten thousand ●●ousand gallons , 〈◊〉 ●or one single drop of wine ? now this being absurd , as f●r beyo●d palliation , as pardon ; is it not much better for us to say , 〈…〉 drop of wine be infused into so large a quantity of water , it is 〈◊〉 into very exile particles , each whereof doth still retain the nature of wine , but so commixed and adhaering to the incommensurably more dense and numerous particles of the water , as that they seem to vanish , though really they still subsist the very same , as before commistion ? that two drops being infused into the ●ame water , the particles therof becoming doubly more numerous , would be contingent and cohaerent to more particles of the water ? that , if ●en , a hundred , a thousand , ten thousand , a hundred thousand , &c. drops of wine be successively superaffused into the same water ; the particles of the wine would at length amount not only to an equall , but a greater number than those of the water : and consequently so praevail over them , as ●o change their virtue , and subdue them into the apparence of wine ? and as to the other ; we might very lawfully except against it , as altogether unintelligible ( for , who can understand , how the inferior mistile can be transmuted into the nature of the superior , and yet not be the very same thing with it ? ) but , least we appear all severity , we shall wave that cavill , and insist onely upon the most important part of the assertion . aristotle saith , that f●om the commistion of two divers things , a certain third thing is generated , or produced , which is of a nature median betwixt , and common to both those things commixed . now , whether is it his meaning , that the resulting middle and common thing doth participate of the extremes of each mistile : or , that it ariseth from the destruction of both mistiles ? for the text will endure no third interpretation . if the latter ; then do not either of the things mixed remain , and so there can be no mistion : expresly contrary to his own assumption , and the tenour of that common notion , for the praeservation whereof he excogitated and designed this subterfuge . if the former , as seems most genuinely inferrible from the adjectives , medium and commune ; then our enquiry is , how , and in what respect , that middle and common thing comes to be participant of the extremes of each mistile ? in the wine ( that we may retain his own instance ) there was matter , there was forme , there were qualities ; and likewise in the water : shall we therefore conceive , that the middle and common thing produced , is participant of all , i. e. matter , forme , and qualities of both the mistiles ; or onely of those of one of them ? ( ) for the matter ; he cannot deny , that the mistum containes the whole matter of both : because neither the matter of the one , nor of the other can be destroyed . and since the matter of each hath parts , the smallest of which is extense or quantitative , and so must possess a proport●onate part of space in the continent ; therefore we demand , whether are the parts of the matter of the wine existent in the very same places , with the parts of the matter of water ; or in distinct places by th●mselves ? if he should say , as the supposition implies , that the parts of both do exist in one and the same place ; he would ruine himself upon that impossibility of the coexistence of two bodies in one place : and if that they are in distinct places ; then must it follow , that they onely touch each other superficially , and so are not mixed by mutual penetr●tion and coextension ( as he affirmed ) but by meer apposition , or composition . ( ) as to the forms ; aristotle cannot but admit , that the forms of both wine and water do survive their commistion , and exist in the mistum ▪ or middle and common thing resulting from them ; because , otherwise , there would be a plain corruption , not a simple alteration of the things mixed , and consequently mistion ought to be defined rather mis●ilium corruptorum , than alteratorum unio : besides , if the formes perish , ●he emergent form must be absolutely new , and so not participant of ●he form of each mistile . but , if he reply , that both forms are unit●d and coexistent in the whole matter of the mistum ; then must eve●y the smallest particle of the matter of each have both the form prop●● to it self , and the form of the other also , and so the whose matter must have two whole distinct forms at once : which is an absurdity 〈◊〉 below the concession of aristotles subtility , and whether or no hi● sectators will defend it , we leave to themselves . to elude this dilem●● . he , indeed , hath determined , that the form of the mistum is one on●● ▪ and that neither of the praeexistent forms , in act , but both in 〈◊〉 . but , alas ! this is a poor shift for so great a philosopher ; for 〈◊〉 ●he praeexistent forms of both mistiles be not actually in the mistum , then are not the mistiles onely altered , but wholly corrupted : 〈◊〉 can i● enter into the thoughts of any sober man , how the resulting 〈◊〉 should contain the praeexistent ones , in power . for , if the result●●● form is capable of being changed again into the praeexistent one● ▪ from which it did result ; as when wine and water commixed , ●re again separated : that argues of necessity , that the forme o● the mistum is not a new forme ( as he assumes ) but one composed of the two praeexistent ▪ ones commixed . ( ) and l●stly , 〈◊〉 for the qualities ; neither ought aristotle to deny the remanence of 〈◊〉 : for , since in them consisteth the chief capac●ty o● power of ●●●overing the last forms ; if they perish , how can they be in●e●vien●● 〈◊〉 ●he recovery of the forms ? necessary it is , therefore ▪ that the 〈◊〉 of things commix't be onely interchangably refracted , not ab●●●shed . and thus have we demonstrated , that aristotle , aswell as the ●t●icks , engulfed himself in an ocean of bottomless diffic●ties , an●●r●econcilable incongruities ; while he sought to propugne that unre●●onable opinion , of the mutuall confusion , and transmutation of 〈◊〉 things commixed in generation . for a collatera● remark ▪ be 〈◊〉 to reflect upon this great example , when you would e●force , how 〈…〉 burthen lye's upon those shoulders , which take upon th●m to support an 〈◊〉 : and how weak the armes of the most giant 〈◊〉 are found 〈◊〉 they strive to bear up against the stream of truth . having detec●●● 〈◊〉 sundry difficulties , that wait upon the doctrine of aristotle ▪ ●ouching the origination , or emergency of a form , in a thing 〈◊〉 from divers things commix't ; let us proceed to another 〈…〉 same cha●ter and enquire whether there be no● also 〈…〉 difficulty inseparable from his doctrine of the es●ence 〈…〉 ; that so at length we may the better 〈◊〉 ▪ w●ether the forme of a thing generated from elements , or other more compound bodies commix't , be a substance ( as aristotle contends ) or onely some certain quality , or accident ( as democritus and ●picurus assert . ) but , first , we are to advertize , that from this discourse of ours , against the substantiality of forms generated , we exempt the rationall soul of man ; for , that being an essence sepa●●ble from the body , and subsisting entire and complete after separation ( as we intend , if god shall be pleased to grant us health , and the world vacation from publique cares , to demonstrate at large , in a singular treatise ) may therefore be most justly termed a substance , o● form substanti●ll : as intending onely to examine the reasonableness o● th●● opinion , by the schools imputed to their master aris●o●le ; that the forms of things are substantiall , and wholly distinct 〈◊〉 matter . the quaestion ( and indeed a very great one ) is , wherein that substan●e , or form , which aristotle affirm's to arise , de novo , in generation , lay hid before generation ? his sectators un●n●mously t●ll us , that it was contained in the matter , not in act , but onely in power , or capacity : and we demand again , if it were not actu●lly contained in the matter , how could it be actually 〈◊〉 ●●om thence ? they reply , that it is educed out of the m●tter on●ly by the power of the agent . but , this is a shamefull desertion o● the quaestion , which is not about the power of the agent ; but , how the ●orm of a thing , which themselves assume to be a subst●n●e , i. e. a reall and self-subsisting entity , and so clearly distinct from the matter of the mistum , can yet be educed out of that very matter ? when they say , that the form is conce●led in the power of the m●tter ; if they would but permit us to understand the form to be a certain portion of the matter , and as it were the flower , o● pu●●r part thereof , which should afterw●rd , in gener●tion , be attenu●ted , refined , sequestred from the grosser m●ss ; and then be again conjoyned to the same , and as it were animate it : then , indeed , might the eduction of a form , as a reall ●nd substantiall being , be easily conceived , and assented to . but , ●his they expresly prohibite , lest they should incur a double contradiction : the one , in ●onceding the matter to be corruptible ; the other , in allowing the form to be indistinct from matter . forasmuch , therefore , as they protest against that interpretation of the text ; and yet are peremptory , that the very substance of the form educed , wa● before eduction potentially comprehended in the very substance of the matter : they give us the trouble of still pressing them to explain how , or after what manner , the substance of the f●rm was potenti●lly contained in that of the matter ? and here they fly to their accustom'd refuge , an obscure distinction , saying ; that the power of the matter , in respect to the form , is 〈…〉 eductive , forasmuch as the form may be , by ●●rtue o● 〈◊〉 ag●nt , educed out of it ; ( ) receptive , forasmuch as it rece●v●s that same form educed . and so they conclude , that the m●tter doth c●ntain the form in both these powers , or double capacity . but , this will not blunt the edge of curiosity . for , as to the ●●rst , viz. the 〈◊〉 power ; 't is manifest , that to contain a thing by an 〈◊〉 power , imports no more , nor less than this , to have actually in it self that , which is capable of eduction from it . thus a purse , wherein ten pieces of money are actually contained , may well be said to contain them by an eductive power ; because he that hath the purse , may at his pleasure educe them from thence : but , if the purse did not actually contain them , he that wanted money , might starve before he could prove , that they were contained therein by an eductive power . and therefore we may set up our rest in this conclusion ; that as a piece of gold cannot be educed out of an empty purse : so doth not 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , o● exforme matter ( so themselves determin e it to be ) contain a form , by an eductive power . as to the other member of the distinction , the receptive power ; t is also mani●●st , that to contain a thing by a receptive power , is no other than to be in a condition of receiving it : but , this capabili●● , or power receptive comes much short of being sufficient , that any thing should be actually educed from that , which hath onely such a power of entertaining it ; since otherwise the prodigall need not fear the exhaustion of all the money in his purse , becaus● it is capable of more , when that 's gone . which being most grossy absur'd ; it cannot be less absurd to conceive , that the form of a thing may be educed from the matter thereof , because it is contained therein by a receptive power . indeed , if they would allow the form to be , not a substance , but a certain quality , species , or modifi●ation of a substance or matter ; then might we understand how it might be contained in the power of the matter ; because the sense would be no more than this , that the matter is capable of being so changed and disposed , as to be put into such a mode , or form● by the same reason , as the species , or image of mercury may be s●id to be contained in the power of a piece of wood , or be e●uced out of it ; insomuch as the wood is capable of being formed ●●to the statue of mercury , by the hands of the statuary . but , while t●ey make the species or image of mercury , to be a new subst●●ce , absolutely distinct from the wood , which is the substance , 〈◊〉 matter of that image ; and in generall discriminate the figu●e ▪ or forme of a thing , from the substance of the thing it self 〈◊〉 we are to be excused , if we do not at all understand them , in ●ore than this , that they endeavour to assert what themselves do no● ▪ nor cannot understand . but , as for 〈◊〉 other philosophers , formerly nominated ; if you please to 〈◊〉 your attention to the summary of their theory concerning the 〈◊〉 argument , we doubt not but in the conclusion you will 〈◊〉 with us in this judgement , that they speak ●at leas● bo●● much more intelligibly and satisfactorily . they deny not ▪ tha● generation is indeed , determined to a substance● ▪ 〈…〉 the thing produced or generated , is a substance . nor that 〈◊〉 ●●neration there alwayes ariseth a forme , by which the 〈◊〉 generated is specified ; because generation supposeth 〈◊〉 , and specification imports a forme . nor , again , that 〈◊〉 ●orm is really a substance , i. e. a certain most tenuious , most spiritual , and so most active part of the body , such as we h●ve o●ten hinted the soul of a plant or brute animal to be . but the points which they declare against , as manifestly unreasonable , are these two : ( ) that such a forme is a new substance , or formerly not existent ; because it is unavoidably necessary , that that most tenuious , m●st spiritual , and most active portion of the matter should be somewhere praeexistent , be●●re it was copulated to the grosser and less active part of the mass , and affected it with such a particular mode , as specifies the mistum : ( ) that that which is properly called the forme of a thing , is ought else but a certain ●uality , or determinate manner of the substances exist●ng , or special modification of the matter thereof . for , it being unanimously decreed by them all , that every thing is generated from an aggeries of matter , or material principles , coalescing in a certain order and position : they therefore determine , that the thing generated , or concreted , is nothing but the very m●t●r●al principles themselves , as convened and coalesced in this or that determinate order and position , and so exhibited to the cognizance of our senses , under this or that determinate forme , species , or quality . and lest we should delude our selves , by a gross apprehension , that the tenu●ous and more agile part of the b●dy is on●y confused●y blended together with the gross and less agile part ; empedocles and anaxagoras tell us praecisely , that the forme of the whole , or ●uality by which the body is made such as it is , doth yet result from as well the order and situation of the tenuious parts among themselves , and of the gross●r among themselves , as of the tenuious and grosser con●unctively , or one among another . and this they illustrate by the similitude of an hou●e . for , as an house is nothing but timber , stones , morter , an● other materials , ●ccording to such or such a reason and order disp●sed an● contexed together , and exhibiting this or that forme ; and ●s there is nothing in it , which before the structure thereof was not found in the wood , quarry , river , and other places , ●nd which a●ter its demolition ( whereby its forme perisheth ) doth not still exist in some place or other : so is a horse ●for example● nothing else but those material principles , or exile bodies , of which after a certain manner connected among themselves it is composed , both with this determinate conformation of members , and this interior f●cu●ty of veget●tion , and in a word , with this particular forme , ●u●lity , species , or con●●tion , which denominates it a horse ▪ when yet the principles of which ●oth its grosser members are coa●unated , and its tenuious and spiritual subst●nce , the soul , is contexed , w●re fo●merly ex●stent in his progenitors , in gr●●s , in water , aer , and other concretions ; and the form also , so ●oon as the co●positum is dissolved , vanisheth , as well the tenuious as grosser particles returning again to aer , water , earth , or other bodies , as they were before their concretion , or determination to that particul●r species ofthings , by gener●tion . but , demo●ritus , epicurus , and leucippus are somewhat more full and perspicuous in their solut●on of this problem , declaring ● ● that , when a thing is generated , multitudes of atoms are congregated , commixe● , c●●posed , disposed , & complicated a●ter su●h a dete●minate manner , as that ●●om thence doth necessarily result a body of such a particu●ar species , ●pparen●e , and consequently of such a respect●ve denom●nation . ( ) that in su●● a body there is no substance , which w●s not praeexistent ▪ it being im●ossib●e that new atoms whi●h only constitute c●rpore●l 〈…〉 shoul●●e created : but only that 〈◊〉 certain d●spositi●● 〈◊〉 of the atoms , eternally praeexistent , is made , 〈…〉 s●cha form 〈◊〉 , which is nothing really distinct from , but is the very atoms themselves , as they are thus , and no otherwise ordered and composed . ( ) that the forme of a thing , considered abstractly or by it self , is therefore onely a meer quality , accident , or event , of wh●ch the atoms , which compose that body or substance , are naturally capable , when thus consociated and mutually related : whether we understand it to be the forme of the whole compositum , or of that most subtile and active part of the substance commonly called the soul , or specifical forme ▪ v. g. of an horse ) the same being ( not a new , or freshly created substance , as aristotle , and the schools upon his authority conceive , but ) only a certain contexture of the most subtile and moveable atoms in the composition . ( ) that out of the infinite stock of the universal and first matter , uncessantly moving in the infinite space , when such consimular atoms meet together , as are reciprocally proportionate or respondent , and mutually implicate each other by their small hooks and fastnings ; then are generated certain very small bodies , or masses , such as being much below the discernment of th● sense , may be accounted semina rerum , the seeds ofthings : differing from the homaeome●ical principles of anaxageras in this , that though very hardly , yet at last they may be dissolved , and reduced to the single atoms , of which at first they were composed ▪ whereas the homoeomera of anaxag●ras are irresolu●le , ●nd first principles . ( ) that these moleculae , fi●st masses , or smallest concretions of atoms , are the proxime and immediate principles of ●ire , water , aer , and of other things more simple , such as the chym●sts conceive their three catholique principles , sal , sulphur ▪ ●nd mercury to be : from which afterward congregated and comm●●t into greater mas●es , ari●e variou● kin●s of bodies , respectively to the various m●nners of the●r commistion , disposition , and concretion ▪ as animals , v●getables , minerals . ● ● that from the dissolution of bo●ies composed of divers sorts of ●uch first m●sses of atoms , ●uch as animals , plants , minerals , and each of their several species ; divers bodies of more simple c●mpositions may be generated , according as the small masses or complications of atoms , separated , by dissolution , from them , shall be more or less consimilar , and convene again in this or that order and position , or particular species ; as when from wood dissolved by fire , are generated fire , smoke , flame , soot , and ashes . and this is th● summary of the atomists doctrine concerning the essence of forms : which that we may conveniently illustrate , let us a while insist upon that most opportune instance of the generation of those divers things , fire , flame , s●●oke soot , ashes , and salt , 〈◊〉 the dissolution of wood. let us conceive ( ) that wood is a compound body , made up of various moleculae , or small masses of atoms : ( ● that those small masses of atoms are such , as that being congregated , commixt , and according to such a determinate manner disposed , they must in the whole composition , retain the species or fo●me of wood ; but being di●located , s●parated , and after another manner again connexed and disposed , they must exhibite other less compound forms , or species of bodies : ( ) that in the concretion there are exis●ent multitudes of spherical , most exile , and most agile atoms , such as , when they are expeded from the ●etters of the g●osser mass , and flye away together in great numbers , and consociated , are comparated to make and exhibite the species of fire : ( ) that of these igneous particles is generated flame . whos 's clarity & splendor ariseth from the abjection of other dissimilar and impure parts , formerly commixt with the igneous particles . whose tendency vpwards , and succeeding disapparence arise both from the force and pernicity of the igneous particles in their exsilition , and the pres●ure or urgency of the ambient aer . whose gradual attenuation , and conicall figure arise from hence , that the igneous particles , in respect of their roundness , exility , and superlative mobility , evolving and expeding themselves from the concretion the soonest of all others contained therein , and in swarms diffusing themselves through the environing aer , on all sides , do create a light , which is by degrees so exhausted , in regard of the speedy avolition of the igneous atoms composing it , that it dwindles or consumes away to a cone or sharp point , which is also much more rare then the basis , where the igneous particles are most dense and agminous . whose dilatation from its base to some degrees , and tremulation or vndulation arise from the copious , but indirect emption of the igneous particles , disengaging themselves from the grosser parts of the mixture . whose obnubilation by some smoke commixt with it , is caused by the many fuliginous particles , that the igneous ones carry off with them , as they flye away . whose faculty of pungency , penetration , and dissolution of most bodies objected , consisteth in the transcendent subtility of the igneous particles , and in the pernicity of their motion , as we have largely declared in our praecedent discourse of the nature of heat . ( ) that the fume , or smoke issuing from wood in combustion , together with flame , is much more simple than the wood it self , but yet compounded of divers particles , some whereof are watery , others earthy , others salt , others fuliginous , as appears by the adhaerence of the soot to the chimny , by the praecipation of the earthy faeces of soot to the bottom of a vessel of water , and the extraction of salt from thence by a dissolution of soot in warm water , and the denigration of things thereby . ( ) and lastly , that what we have conc●ived of flame and smoke , may be equally reasonable , if applied also to the remaining ashes of wood burned , they being likewise composed of various particles or small masses both of salt and earth ; and the particles of earth being again composed of mud and sand , or such as that of which glass is made . and when we have perpended the verisimility of these conceptions , we shall be fully convinced ; that wood is a thing composed of divers sorts of small bodies , or minute masses of atoms ; and that the form thereof doth consist in the congeries , concretion , complexion , and determinate disposition of them all ; as also that the fire , or flame issuing from ●t in combustion , is a thing likewise consisting of various sorts of particles contained in the wood , and which being separated , and again consoc●ated ( according to the consimilarity or likeness of their natures ) and concreted among themselves , obtain another disposition , and forme , and so exhibite the species of a new body . sect . ii. from generation ( ●s in the method of nature , so in our disquisitions concerning her ) we pass to corruption ; which is no more but the dissolution of the forme , i. e. the determinate modification of the matter of a thing , so that it is thereby totally devested of the right of its former denomenation . for , since it is most certain , that in generation , there doth arise no such new substantial forme , as aristotle dreamt of , and most men have ever since disquieted their heads withal : it can be no less certain , that neither in corruption can any such form , as ever was substantial , perish or be annihilated . which verily that we may most commodiously enforce , resuming our late instance of the generation of fire , flame smok , &c. from the combustion of wood , we shall to our praecedent remarks there thereupon , superad this observation ; that when wood perisheth by fire , and so is resolved into divers other bodies , it is not resolved into any other , but those very same things , which were really praeexistent and contained therein ; and consequently , that nothing thereof perisheth , but only that determinate connexion and situation of its parts , or that special manner of their existence , ( you may call it forme , quality , species , accident , or event ) in respect whereof it was wood , and was so denominated . a strange assertion you 'l say , that there is really existent in wood , fire , that there is flame , that there is salt , that there are all those divers things into which it is resoluble by corruption . and yet the truth much transcends the strangeness of it ▪ the difficulty , at which you are startled , consisting only in name , not in the thing it self . for , if by fire you understand burning coales or flame actually ardent and lucent ; and if by salt you conceive a body sapid , really and sensibly corrading the tongue : then , indeed , we shall confess that there is no such fire , nor flame , no such salt existing actually in wood : but , if you b● the names of fire , and salt , understand ( as the tenour of our dissectation , both directeth and obligeth you to understand ) the seeds , or small masses , or first concretions of fire and salt , such which ar● so exile , as that each of them singly accepted is very much beneath the perception and discernment of the most acute of senses ; but ye● when multitu●es of them are sequestred from the whole mass , and are again congregated and freshly complicated together , the seeds o● fire by themselves , those of salt by themselves ; then do these actually burn and shine , and those actually make a sapour , sharply affecting and corrading the tongue : we see no reason , why you should wonder at our tenent , that both fire and salt , viz. that very fire which burns and shines in the wood , that very salt which may be extracted from the ashes thereof , were praeexistent in the wood . certainly , you cannot but admit as highly consentaneous to reason ; that in a vapour to what rate soever attenuated , there are contained the seeds of water , or the first concretions of aqueous atoms ; which though singly existent they are wholly imperceptible , yet nevertheless are they really particles of water : for as much as they want only the convention and coalition of many of them together , to the discovery of their nature in sensible masses ; for of many of them condensed are made very small drops of water , of those drops assembled together arise greater drops , of those rain is generated from that rain arise whole streams ▪ and many of those streams meeting together swell into great and impe●uous torrents . and if this be so easily , why should that be so hardly admittible ? but to desert this example , and address to another so competent and illustrious , that it takes off all obscurity as well as difficulty from our conception ; it is well known , that silver is capable of such exact perm●stion with gold , as that though there be but one single ounce of silver admixt by confusion to ounces of gold : yet in the whole mass there shall be no sensible part , wherein somewhat of that small proportion of silver is not contained . now , you cannot expect that each single molecula , or seed of silver should appear to the sense , so as to distinguish it self , by its proper colour from the small masses of gold : because each molecula of silver is surrounded with , and immersed among particles or small masses of gold. nor can you believe , that the silver is wholly unsilvered , or changed into gold ; as aristotle affirmed , that a drop of wine , infused into a great quantity of water , is changed into water : because the skilful metallist will soon contradict you in that , by an ocular demonstration . for , by aqua fortis poured upon the whole mass , he will so separate the silver from that so excessive proportion of gold , as that there shall not be left inhaerent therein so much as one the smallest particle thereof ; and in the superfice you may plainly discern multitudes of very small holes , ( like punctures in wax , made by the point of the smallest needle ) in which the moleculae or small masses of the silver were resident , before its sequestration from gold. why therefore , according to the same reason , should it not be equally probable , that the seeds , or particles of fire are so scatteringly diffused through the substance of wood , as that being surrounded and overwhelmed with myriads of particles of other sorrts , they cannot therefore put on the apparence proper to their nature , and discover themselves to be what really they are , until being by the force of the external fire invading and dissolving the compage of the wood , set at liberty , and disengaged from their former oppression , they issue forth in swarms , and by their coemergency and consimilarity in bulk figure and motion being again congregated , they display themselves to the sense in the illustrious forme of fire and flame , and proportionately diminish the quantity of the wood ; which thereupon is first reduced to coals , and a●terward , the separation and avolation of more and more particles successively being continued , to ashes , which containing no more igneous particles , can maintain the combustion no longer . the like may be said also of the salt , diffusedly concealed in wood. for , insomuch as each single particle of salt ambuscadoed therein , is blended among , and as it were immured by myriads of other particles : it is impossible they should exhibite themselves in their genuine forme , while they remain in that state of separation or singular existence ; which they must do , till the compage of the whole mass or concretion be dissolved . and would you be , beyond all pretext of doubt , convinced , that they yet retain their proper nature , amidst such multitudes of other particles ; be pleased only to make this easie experiment . take two pieces of the same wood of equal weight , and steep one in water , for two or three days , and keep the other from all moysture ; then by fire reduce each of them apart to ashes , and by water a●●used thereunto , and boyled to a lee , extract the salt from the ashes of each : this done , you shall find the ashes of the drie piece to have yeelded a quantity of salt proportionate to its bulk , but those of the wet one very little , or none at all . and the reason is only this , that the water in which the one piece was macerated , hath exhausted most part , if not all of the salt , that was contained therein . now this example we alledge to praevent your falling upon that vulgar conceit , that the salt of ashes is produced only by the exustion of the wood : since , according to that supposition , the macerated piece of wood would yeeld as much of salt , as the drie . this considered , it remains a firm and illustrious truth , that all the particles of the fire , salt , smoke , &c. educible from wood , were really praeexistent therein , though so variously commixt one among another , as that notwithstanding each of them constantly retained its proper nature entire , y●t could they not discover themselves in their own colours , proprieties , and species , till many of each sort were dis-engaged from the concretion at once , and assembled together again . now such are the advantages of this theory above that of aristotle , that besides the full suf●ragation of it to the common notions of generation and corruption , of substance , forme , &c. it assists us in the exposition of three general axiomes , which though drawn into rules by aristotle himself , are partly inconsistent with , partly unintelligible from his doctrine . the first is , si aliquid corrumpitur ultimum abire in primam materiam , that when any thing is corrupted , it is at last reduced to the first matter : which doth expresly contradict his grand thesis , that the forme of a thing is a substance , which begins to be in generation , and ceaseth to be , or is annihilated in corrupt●●n ; for , had he spoken conformably thereto , he must have said , that when the compositum is dissolved by corruption , it is partly reduced to matt●r , partly to nothing . but , if the form be not substantial , and that what is corrupted , is composed of no other substantial parts , but those wh●ch are material ; as we have assumed : then , indeed , doth the axiome hold good , and we may with good reason say , that when any thing is corrupted , it is reduced to matter , or the material parts , of which it was composed , as wood dissolved by fire , is reduced to fire , smoke , soot , ashes , &c. of which it did consist . and forasmuch as by that adverb , ultimum , finally , he gives us the occasion of enquiring , an in corruptione detur resolutio adusque materiam primam ? whether or no in corruption there be a resolution even to the first matter ? we cannot but observe , that the manner of that ultimate resolution may be much more easily comprehended , according to our assumption , than according to his own . because our first matter is atoms , and the second matter certain small masses of atom● , or the first concretions , which we therefore , observing the phrase of ●picurus and lucretius , call semina rerum , the see●s of things , such 〈◊〉 those whereof fire , silver , gold , and the like concretions are composed ▪ and so , if the resolution proceed to extremity , i. e. to atoms , or in●●soluble particles ( as in some cases it doth ) then may it well be said , that the resolution is made to the first matter ; but if it go no farther then those ●●all masses of atoms ( as most commonly it doth not ) then can we just●● say no more , than that the resolution is made only to the second matter . the second is , corruptionem unius esse generationem al●erius , that the corruption of one thing is the generation of another , which cannot consist with truth , if understood in any other sense but that of our supposition· for , since , corruption is nothing else but a separation and exsolution of the pa●ts , of which a thing was composed : we may conceive , how those parts so separated and exsolved , may be variously convened and commixt again afterward , as to constitute new concretions , & put on other new forms . not that they were not formerly existent , as to all their substantial parts : but only that they were not formerly existent in a state of separation from others , nor coadunated again in the same compage , and after the same manner . the third , id quod semel corruptum est , non posse idem numero naturae viribus r●stitu● , that what is once corrupted , cannot by natures power be again restored numerically the same : which is to be understood in this sense . as a watch , or other artificial machine , composed of many several parts , may be taken in pieces , an● easily r●●omposed again into the very same numerical engine , both as to matter and forme ; the artificer recollecting the divided parts thereof , and so disposing them , as that each possesseth the s●●e pl●ce and position , as before its dissolution : so likewise might the same n●tural comp●situm , v. g. a piece of wood , be , after the separation and e●so●ution of all its component parts , again recomposed numerically the very same , both as to m●tter and forme , in case all those dissolved parts cou●● be recollected , reunited , and each of them restored to its former pl●ce and position . but , though all the various parts thereof remain , yet are they so scattered abroad into so many and so various places , and commixt ( perchance ) with so many several things , that there is no natural power th●t can recollect and restore them to the same places and positions , which they held before their disunion and dissolution . and , therefore , if any man shall say , that such or such a thing , dissolved by corruption , is capable of being restored again the same in specie ; we ought t● understand him no otherwi●e than thus : that some of the parts of that thing may so return , as that being conjoyned to others , not numerically the same , but like unto those , to which they were formerly conjoyned , they may make up a body ex●ctly like the former , in specie or of the same denomination ; as when the c●rcase of an horse is corrupted , some parts thereof are converted into ea●th , some of that earth is converted into grass , some of that grass e●t●n by another horse , is again converted into seed , whereof a third hor●e is generated . and thus are we to conceive the endless circulation of forms . as for the principal causes of corruption , ( omitting the consideration of such as are external , or invading from without , in respect they are innumerab●e ; and of that internal one also , the intestine war of elements in every concretion , of which aristo●le hath such large discourses , and the schools much larger ) the theory of epicuru● instructs us , that they are only two. the fi●st and g●and one is the intermistion of vacuity among the solid particles of bodies ▪ in respect whereof all concretions are so much more easily exsoluable , or subject to corruption , by how much more of vacuity they have intercepted among the solid particles , that compose them : according to that d●stich of lucretius . et quam quaeque magis cohi●et res intus inane , tum magis his rebus penit●s tentata labascit . the other is the ingenite gravity ▪ or natural and inamissible propensity of atoms to motion which always inciteth them to intestine commotions and continual attempts of exsilition . so that where their connexions and complications are but lax , and easily exsoluble , as in all animals , all plants , and some metals , there do they sooner and more easily expede themselves , and so in short time totally dissolve the concretions , which they composed . but , where they are bound to a more lasting peace , by more close compaction , and reciprocal complications , as in gold and ad●m●nts ; there their inhaerent propensity to motion is so supprest , as that they cannot diseng●ge themselves each fro● other , without great difficulty , and after many hundred yeers continual attempts of evolution , convolution and exsilition . which is the true reason both why gold is the le●st corruptible of all things yet known ▪ and why it is not wholly incorruptible , but obnoxious to spontaneous dissolution , though a●ter perhaps a million of yeers , when after innumerable myriads of convolutions , the atoms which compose it , have successively attained their liberty , an● flye off one after another , t●●l the whole of that so closely compacted substance be ●i●solved . from the causes , our thoughts are now at length arrived at the manners , or ways of generation an● corruption ▪ and fin● them to be of two sorts , general and special . concerning the general we ob●e●ve , ●●at accord●ng to the do●trine of epicu●us , ( who●e great praehe●inen●e in point of verisimility and concordance throughout , hath ma●e us prae●er it to that of aristotle , which we have am●ly convicted of manifest incomprehensibility , and self-contradiction ) things are generated either immediately of atoms themse●ves convened together and concreted , and resolved again immediately into atoms ; or immediately of praeexistent concretions , and resolved imm●●iately into them ag●in . of the way how the former is effected , we have said enough , in the second chapter of our d●scourse against atheism . a● to the latter , be pleased to unde●stand , in a wor● , that all generation is caused by either ( ) a simple transposition of pa●ts of the same numerical matter , or ( ) an abject●on of some pa●ts of the old ▪ or pr●●xistent matter , or ( ) an accession of new parts . for , howbeit all these three general w●ys of generation are mostly so concurrent an● commixt , as that one is hardly found w●thout the association of the other two : yet when we consider ●ach of them in special , and would determine which of them is praedomin●nt over the others , in the generation of this , or that particular species of ●hings : it will be necess●●y , that we allow this discrimin●tion . first , the●●●ore , those things ●re s●●d to be generate● [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] by a meer t●ansposition of parts , which are observed to be spontaneous in their pro●uction ; as frogs engendred only of mu● or sl●●e , worms from putrid chees , &c. because from the very ●elf-s●me praeeist●nt matter , only by a various transposition of its parts , & succeeding re●uct●on of them to such , or such a determ●n●te order & situation , ●o●ething is generated , of a nature absolutely new or qu●te different from what th●t m●tt●r formerly had . an●●●ther also are we to refer tho●e transmuta●●●●● of ●lements , of which ar●stotle and the sc●ools have such frequent ●nd high discourses : because , when aer is conceived to be changed into water , or water transformed into aer ; all the mysterie of those reciprocal metamorphoses amounts to no more , than a meer putting of the parts of the same common and indifferent matter into different modes , and the interception of more or less of inanity among them , as we have frequently demonstrated . secondly , such things are conceived to be generated [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] by addition or accession , which are not spontaneous in their original , but of seminal production , and specificated by the univocal virtue of their seeds : because in propagation , rightly accepted , a very small quantity of seed , pervading a greater mass of matter , doth ferment , coagulate , and successively appose more and more parts thereof to itself , and conform the same into the species of that thing , from which it was derived , and impraegnated with the idea of the whole and every part thereof . and this difference includes not only all augmentation , which is a kind of aggeneration , and consisteth only in the apposition of new matter or substance , and that in a greater proportion than what is decayed or exhauste● : but also every composition whatever , such as is the insition or inoculation of plants . thirdly , such things are said to be generated [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] by detraction which arise from the dissolution of others , and subsist only by excretion or separation ; as fire , smoke , &c. are derived from the dissolution of wood , and other combustible substances , to which they were formerly commixt ; and wax from the separation of hony , together with which it was blended in the combs . and , as for the contrary , corruption , ●tis easie to deduce it from the contrary ways of disposing matter . and here again the incircumspection of aristotle manifestly discovers it self ; who multiplies the general ways of generation , to a superfluous number : expresly teaching , that every simple generation ariseth from ( ) either transfiguration , as when a statue is made of molten metal ; or ( ) addition , as wh●n vegetables or animals are augmented ; or ( ) ablation , as when a statue is hewn out of marble , all such parts being cut off and abjected , as were superfluous to the perfection of the figure designed ; or ( ) composition , as in the structure of a house of various materials composed , according to the rules of architecture ; or ( ) alteration , when a thing is changed as to matter , as when ashes are produced out of wood combust . when notwithstanding , had not his accustomed diligence been laid asleep , or judgement perverted , he must soon have perceived , that his transfiguration , addition , and ablation are really the very same with the transposition , adjection , and detraction of our epicurus ; and that composition is necessarily referrible to addition , and alteration to transposition . concerning the special modes , or ways of generation , we need advertise you of only two considerables . ( ) that each of the three general ways , newly mentioned , is so fruitful in possible variety , as that the special subordinate ones , whereof it is comprehensive , are ( if not infinite , yet ) absolutely innumerable , ineffable , incomprehensible . for , if the letters of our alphabet , which are but in number , may be so variously composed , as to make such a vast diversity of words , which cannot be enumerated by fewer then c●phers , viz. . ( tantum elementa qu●unt , permutato ordine solo ) what arithmetician can compute the several special ways of composition , whereof that incomprehensible variety of figures which ( as we have frequently assumed ) atoms may bear , is easily capable ? ( ) that , as the image of mercury cannot be carved out of every stone , or every piece of wood ; nor words fit for reading , or pronunciation arise from every commistion of letters : so , in natural concretions is it impossible , that all things should be made of all sorts of atoms , or that all atoms should be equally accommodate to the constitution of every species of concretions . for , though atoms of the same figure and magnitude may , by their various transposition , adjection , ablation ▪ compose things of various forms or natures : yet are they not all indifferently disposed to the composition of all things , nor can they be connected after one and the same manner , in divers things . because , to the composition of every thing in specie , is required such a special disposition in the atoms , which compose it , as that they must appose to themselves such other atoms , as are congruous and suitable to them , and as it were refuse the society and combination of others that are not . and hence is it , that in the dissolution of every concretion , the consimular or like atoms always consociate together , and expede themselves from the dissimilar and incongruous . chap. ii. of motion . sect . i. certainly , the great galilaeo did most judiciously and like himself , to lay the foundation of his incomparable enquiry into the most recondite mysteries of nature , in the consideratin of the nature of motion , and severe examination ( that we may not say , subversion ) of aristotles doctrine concerning it . bec●use , motion being the heart , or rather the vital faculty of nature , without which the universe were yet but a meer chaos ; must also be the noblest part of physiology : and consequently , the speculation thereof must be the most advantageous introduction to the anatomy of all other parts in the vast and symmetrical body of this all , or adspectable world. again , if motion and quiet be the principal modes of bodies existing , as des cartes ( in princip . philosoph . part . . sect . . ) seems strongly to assert ▪ if generation , corruption , augmentation , d●minution , alteration , be only certain species , or more properly the effects of motion , as our imme●●●tely praecedent ch●pter cleerly imports ; and that we can have no other cognizance of the conditions or qualities of sensible objects , but what results from our perception of the impulses made upon the organs of our senses , by their species thither transmitted : assuredly , the physiologist is highly concerned to make the contemplation of motion , its causes , kinds , and universal laws , the first link in the chain of all his natural theorems . and , truly , this we our selves had not endeavoured , had not our firm resolution to avoid that ungrateful prolixity , which must arise from the frequent repetitions of the same notions , in the solution of various natural apparences ▪ and our design of insensibly praeparing the minde of our 〈…〉 the gra●ual insinu●ti●n of all both c●uses and effects o● 〈…〉 , as they stood in relation to this or th●t particul●r sensible 〈◊〉 , ●nd principally to visibles , and the grav●tation of bodies : not only inc●●ed , but by a necessity of method almost constrained us , to make that the he● , or fringe , which otherwise ought to have been the first thread in this rawe and loosely contexed web of our philosophy . nor , indeed , can we yet praevent all repetitions ; for , our praesent th●orem being physicomathematical , and such as must borrow some light , by way of reflection , from ●●ndry observables , occasionally diffused upon several of our discourses praecedent : we need not despair of a dispensation for our recognition o● a few remarkable passages , directly relating thereunto , and especially of these three epicu●ean postulates , or principles . the first , that 〈◊〉 adam or radical and primary cause of all motion competent to concretions , i● the inhaerent gravity of their materials , a●oms ▪ whether the 〈◊〉 be moved spontaneously , or violently , i. e. by it self ▪ or another . the reason of its spontaneous or self-motion may be thus conceived . whil● atom●●re , by their own inamissible propensity to motion , variously agitated and ●umultuous in any concretion ; if those which are more movea●●● and agile then the rest , so conspire together in the course of their tendency , as to discharge their united forces upon one and the same quarter o● 〈◊〉 body containing them , and so attempt to disengage themselves towar●●●●t region : then do they propel the whole body toward the same region , transferring the rest of their le●s active associates along with them . it being h●●hly consentaneous , that motion may be expressed first in the singular atom● themselves , then in the smallest masses , or ●nsensible combinations of atoms ; and successively in greater and greater , till the sensible parts of 〈◊〉 , and at length the whole bodies ●hemselves participate the motion , an● undergo manifest agitation : as lucretius ( in lib. ●● ) hath with lively arguments asserted . and this , certainly , hath far a stronger claim to our assent , than that fundamental position of a●istotle ; that the first princ●ple of motion in any thing , is the very form● of the thing moved . for , unless he shall give us leave , by the word 〈◊〉 , to understand a certain tenuious contexture ●f most subtile and most active atoms , which being diffused through the body o● mass consisting of other less subtile , and in respect of their greater compaction together , or 〈◊〉 close reciprocal revinction , less active atoms ; doth , by t●e impression 〈◊〉 its force or virtue motive , upon the whole , or any sensible part thereof become the principle of motion to the whole body : we say , unless he 〈◊〉 be pleased to allow us this interpretation , we shall t●ke the liberty to 〈◊〉 ●hat it is absolutely incomprehensible . for , that the forme of a thing , accepted according to his notion of a forme , should be the proto-cause or 〈◊〉 of its motion ; is unconceivable ; since , according to the tenour 〈◊〉 aristotles doctrine , the forme must be educed out of the matter , or power of the matter , that constituteth or amasseth that thing : and consequently ▪ 〈◊〉 the forme must owe as well its very entity or be●ng , as 〈…〉 onely to the matter it self ; which yet he describe● to be something 〈◊〉 , nothing ) meerly passive , and devoi● of 〈…〉 . how , therefore , can it appear other than a 〈…〉 contradiction to any man , whose intellect is not eclipsed , by reaso● 〈…〉 of it s proper organ ; that that matter , which in 〈…〉 of moving , should nevertheless be able 〈…〉 , and potent activity , upon the form , supposed to be absolutely distinct from matter ? doubtless , the forme doth not derive that motive virtue from the qualities inhaerent in the matter : forasmuch as those qualities , as even the aristoteleans themselves furiously contend , are but the meer results of the power of the matter . nor from the efficient ; because ●hey account the efficient to be a cause meerly external , and to transfuse nothing of it self into the thing generated ; but only to display its efficiency , or ( to speak in their own dialect ) to execute its causality upon the matter . again , it being necessary , that all that virtue of moving , which is in the efficient , should depend solely and wholly upon its forme ; and that forme also ought , by equal reason , to be educed out of the matter : they lose themselves in a round of petitions , and still reduce themselves to the same difficulty , how it is possible , that the matter should give that faculty of mot●on to the forme , which it self never had . the second ; that in general there is no other but local motion ▪ wherein that we may plainly and briefly instruct you , how far epicurus differs from aristotle , plato , and some other philosophers ; give us leave to commemorate unto you . ( ) that aristotle putting a difference betwixt [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] motion and mutation , is not sufficiently constant in his doctrine : sometimes making mutation to be the genus , and motion onely a certain species thereof ; and sometimes , by inversion of the tables , making motion the genus , and mutation a species thereof . for , ( in . physic . cap. . ) stating mutation betwixt two terms , â quo , & ad quem , the from whence and to what ; he assigns unto distinct modes , or manners ; the first , ● subjecto in subjectum ; the second , ex non subjecto in non subjectum ; the third , ex non subjecto in subjectum ; the fourth ex subjecto in non subjectum : and thereupon infers , as of pure necessity , that since nothing can be changed according to the second mode , therefore must mutation according to the third , be generation ; according to the fourth , be corruption ; and according to the first , be motion , which is always either from quantity to quantity , or from quality to quality , or from place to place . whereas , in another place ( viz. ● . physic. . ) he positively teacheth , that motion is a certain act , to which that p●sseth , which is in power ; and so makes the species thereof to be not only those motions , whose terms on either side are positive , or ( in his own phrase ) contrary , as are those which concern ●uantity , quality , place : but those also , whos 's each term is privative , as are those which concern substance . and hereupon he seems to have grounded that memorable division of motion ( lib. de praedicam . cap. de motu . ) into six species , viz. generation , corruption , accretion , diminution , alteration , and lation or loco-motion : whereof the first two are according to substance ; the second two , according to quantity ; the fifth , according to quality ; and the last , according to place . ( ) that plato seems constantly to accept mutation for the genus , and motion for one species thereof : subdividing motion into two species , lation and alteration . forasmuch as in one place ●viz . in polit. ) he terms the conversions of the coelestial bodies , mutations : and in another ● in phaed. ) he takes alteration for mutation ; saying most eloquently in the person of socrate● ( in the●● . ) illu●●e ●overi appellas , du● quidpi●● locum ● loco mutat , aut in ●ode●●onvertitur ? tho. ●quid●m . socrat. illa ergo una sit species motus . a● ▪ cum in eodem quidem p●rs●at ; sed senescit tamen , aut ex albo fit nigrum , ex molli durum , aut alteratione quapiam alterum ●vadit ▪ an non ●ideri 〈◊〉 motu● spe●●em ne●esse est ? tho mihi quidem videtur . socra● . 〈…〉 id igitur ; duas , inquam , esse motus species , alterationem , & 〈◊〉 , circulationemve ? &c. ( ) that most other ●hilosophers , insisting in the steps of plato constitute only two kinds o● motion ; only in this they differ from him , that what he calls [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] , 〈◊〉 , or circumlation ▪ they c●ll [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] transition , or motion transitive : and what ●e names [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] alteration , they denominate [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] mutation or [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] motion mutative ▪ as empiricus ( . advers . physic . ) 〈…〉 observed . ( ) that epicuru● ( 〈◊〉 the same empiri●us , in the same place , attesteth ) is chief of those physio●●●ists , who accounted the motion of transition as the g●nus ▪ and 〈◊〉 or alteration as only the species thereof . and this upon 〈…〉 . forasmuch as alteration is nothing else but the consequen● o● 〈◊〉 , whereby atoms , or the insensible particles of concretions 〈…〉 , decede , concur , complicate , and change their former positions , 〈…〉 ●ender the sensible parts o● whole of them other than they 〈…〉 . which being considered , we are only to advertise farther ▪ that 〈◊〉 argument of our praesent enquiry , is not motition as it is proper to 〈◊〉 , as they either concur to the first constitution of a body , or are 〈◊〉 at the dissolution thereof ; in which respect it may comprehend 〈◊〉 and corruption : nor as they concur to the augmentation of a 〈…〉 constituted , or flye off from it , and by their decedence 〈◊〉 , in which respect it may comprehend accretion and diminution : 〈…〉 they are variously transported , and so conduce to affect the same bod● 〈◊〉 divers qualities ; in which respect it may include alteration . 〈◊〉 concerning motion under all these terms and relations , we have 〈◊〉 discoursed already , in places to which those considerations did 〈◊〉 refer themselves . but , our subject is motion a● proper to a body 〈◊〉 which sensibly changes the place of its whole , or some sensible part . 〈…〉 motion plainly distinguisheth it self from 〈◊〉 that in motio● 〈◊〉 whole body , v. g. of a man , or some sensible part thereof , as his 〈…〉 ●oot is translated from one place to another : but in mutation only 〈◊〉 insensible particles of a body , or any part thereof , change their positions 〈◊〉 places , though the whole , or sensible parts thereof remain qu●et . th● third ▪ 〈◊〉 motion or loco motion ( for , the common notion , 〈…〉 , so soon as he hears the word motion 〈…〉 more intelligibly and properly defined by epicurus , 〈…〉 the migration of a body from place 〈…〉 be actus entis potestate , quatenus est tale . for 〈…〉 one ; so nothing can be more 〈…〉 〈…〉 enough to furnish you with patience , 〈…〉 of aristotle , in that his aenigmatical definition ; we advise you to reflect upon the whole syntax of those conceptions , from whence he seems to have deduced it . know , therefore , that he conceived , that there are some things , which always possess , and in●missibly retain the perfection due to their nature , [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] perfec●i-habit●one , or ( as his expositors commonly render it ) act● solum , in act only : and others ●gain , which are not indeed , without some perfection , but such as they are c●pable of losing , and may at the same time acquire another ; so that they may be said to be [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] both in act and power together . for , he admits nothing to be meerly in power ; because he would not allow , either that matter can exist withou● forme ; or that any thing in nature can be altogether without some perfection . now , those things , which are only in act , must , according to his opinion , be no other but the coelestial bodies ▪ insomuch as they alone seem constantly and in●missibly to posses● their forme , nor can their substan●e or m●tter ●e ●onceived , to h●ve a capa●●ty of ●eceiving any other forme wh●tever . but , those which are both in act and power at once , are all sub●un●ry bodi●s , insomuch ●s their substance , or matter so stands possest of so●e one forme in act , ●s th●t it still remains in a capacity of being d●vested of that ●orme , and in●●sted with a new one ; and the whole compositum ●o hath it● certain quantity , certain quality , certain place , and whatever other ●if there be any other ) perfection requisite to its particular nature , as that it may notwithstanding be totally deprived thereof , and obtain another . know also , that he useth the word , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , sometimes for the perfection already acquired ; sometimes for the very manner of its acquisition , in which ●ense it is a certain action , and so comes to be called [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] an energy ; this being praesupposed ; he infers , that motion is [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] an act , according to the posterior mode : understanding it to be as it were the way , or manner , whereby the perfection is acquired , or the acquisition it self : which is also a certain perfection , but competent to an entity , or moveable , not as it hath a perfection , which it loseth ; but as it hath a power to that , which it receiveth . and hence is it , that he resolved to define motion to be the act of an entity in power , a● it is such . which notwithstanding all the light this our most favourable descant , or any other can cast upon it , is yet mu●h inferior in perspicuity to tha● most natural and familiar one of epicurus ; that motion is the migration or remove of a body from one place to another . nevertheless , to verifie that unhappy proverb , that n● truth can be made so plain , as not to be impugned ; empericus● ● . advers . physic . ) hath charged it with sundry imper●ections . as ( ) that it doth not comprehend the motion of a globe , or wheel circumvolved upon its axis ▪ forasmuch as a wheel , when circumgyrated upon its axe , is sensibly moved , but not removed from one place to another . but to this we may readily answer ; th●t though the whole wheel be no● removed out of its who●e place , yet are the parts of it sensibly transferred from place to place ▪ the superior descending to inferior , while the inferior ascend to su●erio● places , the right hand parts succeeding into the places of the left , as ●●st as the le●t ●●cceed into those of the r●ght , and all parts successively ●hi●t●ng their particular places . and upon this distinction of place into tota● and part●●● ▪ was 〈◊〉 that some philosophers have defined motion to be migrationem de loco in locum , vel totius corporis , vel partis ipsius ; or as chrysippus and apollodorus ( apud s●obaeum , in eccl. phys . ) mutationem secundum locum , aut ex toto , aut ex parte . nay , even plato himself seems to have had an eye upon the same difference , when he said , that local motion was conjunctly lation , or circumlation . ( ) that likewise the point of that arme of a compass , which is fixed in the centre , while the other is moved round , in the description of a circle ; is moved , but not removed out of its place : as is also the hinge of a door , while the door is opened or shut . but , this objection must soon yeeld to the same response , as the former : since t is manifest , that the parts of the point of the compass , and hinge change their partial places . ( ) that there is a certain sort ( he adds , admirable ) of motion , to which the importance of epicurus definition doth not extend ; which is thus made . let a man , in a ship under sail , walk , with a staff in his hand , from the for●●astle to the poup of the ship ; and with just so much speed , as the ship is carried forward : so that in the same space of time , as the ship is moved a yard forward , the man and the staff in his hand may be moved a yard backward . this done ( saith he ) doubtless there must be a mo●ion both of the man and his staff ; and yet neither of them shall be moved into new place , either as to their whole , or their parts : because both must remain in the same parts of the aer , and water , or in the same perpendicular line extended from the mans head to the bottom of the sea ; or , what is the same thing , they shall still possess the same immoveable space . but , this so admirable difficulty lies open to a double solution : for it may be answered . ( ) that in this case , the thighs , leggs , and feet of the man walking upon the deck of the ship , must be alternately moved into new places ; because , as often as each of his feet is referred from the anterior to the posterior part thereof , it must be moved twice as swiftly , as the ship is moved from the posterior toward the anterior : since it is absolutely necessary , that the double velocity of one foot should compensate that space of time , in which the other foo● resteth , while the ship is constantly carried forward in one uniform tenour of motion . and , therefore , his ●eet may be conceived to be alt●rnately moved from place to place ; after the same manner , as a man , sitting on a wooden , or standing horse , doth move his leggs alternately forward and backward : the trunck and upper part of his body rema●ning unmoved , or still keeping the same centre of gravity . ( ) that the trunck of his body also must be moved from place to place ; and also his ●ead , and the staff in his hand : because , at every step , all of them must be somewhat elevated , and again depressed , or let down . for , in progression , the feet of a man cannot be alternately moved forward , but at every time the one foot is set plainly upon the ground , the trunck and so the head and arms , must sink a little downward ; in regard of the distension of the muscles o●●hat thigh and leg : and again when the other leg is advanced , and the leg upon which the whole body resteth the while , is elevated upon the toes , to cas●●he body forward ; the trunck , head and shoulders are lifted a little upward●●n respect of the bodies inclining to a new centre of gravity . for , it is most true , what galilaeo hath most subtly demonstrated , that a man goes , because he falls : since he could not advance forward , while he kept his body a●quilibrated upon the same centre of gravity ; but falling ●orward at each s●●p , he sustains himself with the fixing another foot upon ● new centre of gravity . ( ) that if we suppose an individual , or smallest thing to be turned round in the same place ; there will be motion , but no change of place , either as to the whole , or any part thereof . and we demand , whether by that individual he means minimum mathematicum , or physicum ? if mathematical , the supposition is not to be admitted : because , what is meerly imaginary is not capable of motion . but , if physical ; then admitting the supposition , we answer ; that the reason of the motion of an individual moved round in the same place , is the same with that of the motion of a globe or wheel upon its axis . for , such a body is not said to be individual , or smallest , because it hath no magnitude or parts designable by the minde ; but because there is no force in nature , that can divide and resolve it into those par●s : and therefore , since it is not a meer point , but contains parts superior , inferior , &c. the whole cannot be moved , but some parts must succeed into the places deserted by others ; and consequently there must be loco-motion . though this also be of the number of such events , as can hardly be effected by the power of nature ; forasmuch as such a physical individual being either permitted to its own liberty , would move sponta●●ously in a direct line , not a circular ; or impulsed by another , could not be so exactly circumvolved in a circle , as not to deflect somewhat , more or less , to one side or other . and thus have we resolved all the difficulties , by emperi●us , objected to the definition of motion , given by epicu●u● . but yet we have not ascertained our reader , that there is such a thing as m●ti●n in the world and therefore , that we may not seem to be meerly ●●titionary , in begging that at the hand of another mans charitable belief , which the stock of our own reason is rich enough to afford us : we shall bri●fly touch upon that ●uaestion , an sit motus , whether there be any motion in nature : especially , forasmuch as it is very well known , that among the ancients there was a notable controversie concerning it . for , some , as heraclitus ▪ cratylus , homer , ●mpedocles and protagoras ( as plato [ in theat . ] notes at large ) affirmed , that all things in the universe are in perpetual motion : and others , of which number parmenides , melissus and zeno were the principal , ( as aristotle ( . physic . ) particularly records ) argued , on the contrary , that all things are in perpetual quiet , or that there is no motion at all . now as to the former ; our quarrel against them is not so great , as that of ar●stotle was : forasmuch as it carries the face of very great probability that they intended no more than this ; that all sublunary bodies are in perpetual mutation of their insensible particles , not loco-motion of their sensible parts , or whole ; or , more plainly , that all concretions uncessantly suffer those irrequiet agitations , or intestine commotions of their insensible particles , from which those sensible changes , alteration , augmentation , diminution , generation , and corruption , are by slow and insensible degrees ●ntroduced upon them . and thus even aristotle himself interprets their opinion ; saying ( in . phys . . ) they held , that all things are moved [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] verum id latere experientiam sensuum , that that motion falls not under the observation of the senses . which is no more , than what epicurus , or any man else , imbued with his excellent principles , might have asserted . and as for the latter s●ct ; neither doth our choler boyl up against them , to that height , as did sextus empericus his , when ( in . advers . p●ysic . ) h● could not be content ●o nickname them [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] the standers ; but so far obeys the impuls● o● his passion , as to fly out into opprobrious language , and brand them with the ignominious character of [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] unnaturael philosophers . and our reasons , why we look not upon them w●th so oblique and 〈◊〉 an eye , as the vulgar use to do ; are these . ( ) experience doth 〈◊〉 clearly demonstrate , that there is motion ; as that no man can deny 〈◊〉 he must , at the same instant , manifestly re●ute himsel● with the motion of his tongue . and such is the constant verity of epicurus his logical canon , concerning the certitude of our senses , as to the information of our 〈◊〉 ; as that every philosopher , nay every man ought to allow ●hem to be ju●g●s in cases of sensible objects : and consequently to conclude , with arist●●l● ; ad mentis imbecillitatem debet referri si quis arbitretur omnia quiescer● , & dimisso sensu , rationem requirat . and , certainly , whoso seriousl● impugnes , what the evidence of sense confirms ; is so easie an adversary , as to deserve our smiles , rather than our anger . ( ) divers have app●●hended , that those philosophers , who seemed to impugn the being of motion , did not oppose it in a serious , but purely paradoxical humor , and an ambition of shewing themselves so transcendently acute , as to be able to ●●dubitate truths even of the most manifest certitude . nor are they , indeed , to be understood in that gross sense , which is so generally passant ●mong vulgar authors ; forasmuch as it is much mo●e probable , that p●rmenides and melissus , when they laid down for a maxime esse omnia unum ens immobile , so intended nature , or the all of things , as that they held it , or at least some certain divine virtue constantly dif●used through , and an●mating the vast mass of the universe , to be god , or the supreme being ; whose propriety it is to be immoveable , as being ubiquitary and all in all. and , that zeno himself , the prince of antimo●●●ts , had some such 〈◊〉 ; may be naturally collected , as well from the contents of that book , commonly adscribed to aristotle , concerning xenophanes , zeno and gorgias : as from those very arguments he alleadge● against motion ▪ t●●●mportance of them all declaring , that his supposition was , there could 〈◊〉 no motion , if as well motion it self , as place and 〈◊〉 did consist of in●ectiles , or indivisibles . likewise , as for diodorus , 〈◊〉 fervently addicted 〈◊〉 the eristick , or contentious sect ; manifest it is , that 〈◊〉 grand scope in his whole discourse against motion , was only to evince , that a good w●t cou●● not want arguments wherewith to invade and s●●gger the 〈◊〉 of 〈◊〉 ●hing , than which nothing can be more certain . lastly , as for t●e pyr●honeans , or scepticks ; the design of all their stra●a●●● against motion , 〈◊〉 to have been only this innocent one : to insi●●●●● that no knowle●●e is exempted from doubts ; and tha● the mind of doth detect the sophisme ; for , since the word esse , to be , is , according to common signification , con●●nient as well to things permanent , as successive or fluent ; and according to a peculiarly accommodate signification , competent only to things permanent : it is understood in the former sense , when the quaestion is , 〈◊〉 where it is , or where it is not ? and in the latter , when the subsumption is , but neither where it is , nor where it is not : according to which reason , ●ou doubt , whether a thing be , while it is moving . which considered , when it is enquired , whether a moveable be moved in the place , where it is , or in that , wherein it is not : we are to distinguish thus ; it is moved in the place , wherein it is transiently , and moved in the place wherein 〈…〉 not permanently . and , to your quaestion , whether a thing be no● in a place , when it passeth through a place ? we answer likewise , that it is in a place transiently , not permanently . nor ought this language to ●o●nd strange , since nothing ought to be conceived to be in any other ma●●er , than what the nature thereof doth praescribe : and such is the n●ture of motion , that is should be conceived to be [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] a passing through , not [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] a permansion , or staying in a place . lastly , 〈…〉 the arguments of the scepticks ; they are all grounded upon the 〈◊〉 difficulties as those of zeno and d●odorus : and therefore must subm●t 〈◊〉 the same resolutions . sect . ii. being thus praepared 〈◊〉 considerations of the most genuine notion ▪ most adaequate definition , and primary cause of motion in all concretions ▪ and an 〈…〉 assurance , that there is such a thing as mot●on in the world ▪ the 〈◊〉 degree to which our enquiry is to advance , ●s the 〈◊〉 gener●l and 〈◊〉 kinds thereof ▪ among which , the first we meet with , 〈…〉 common distinction of motion into natural and violent . a natural motion , 〈◊〉 aristotle● ● . physic . . ) is that , whose principle is internal ; and a 〈◊〉 , that , whose principle is external : so that , accordingly ▪ that bo●● 〈◊〉 be said to be moved naturally , which is moved 〈…〉 , which is moved by another . but , for as much as aristotle 〈…〉 much amuse us , while he ever and anon 〈…〉 be moved by another , and yet not be moved 〈…〉 may be said to be natural or violent , in 〈…〉 that some more easie and familiar notion is 〈…〉 of those contrary terms , natural and 〈…〉 more convenient for us , to understand a 〈…〉 which is made either of natures own accord , or with●●● 〈…〉 violent to be that , which is made either prae●●● 〈…〉 repugnancy . thus , the progressive motion of 〈…〉 made of natures own accord ; and yet if 〈…〉 a steep hill , leap , or run , the motion is to be accounted violent , because though it proceed from an internal principle , the soul of the animal , yet is it not performed without some repugnancy , either internal or external . on the contrary ; when a bullet is shot through the aer , the motion thereof is violent , because against the nature of the bullet , and not performed without some repugnancy , either internal or external : and yet if the same bullet be rowled upon a smooth plane , the motion thereof is natural ; because though it be caused by an external principle , yet is it performed without any repugnancy either internal or external . but , that we may take the matter in a higher key , reflecting upon that so often inculcated epicurean principle , that all the motive virtue of concretions is originally derived from the mobility inhaerent in , and inseparable from atoms , which compose them ; let us observe , that forasmuch as that essential mobility of atoms doth neither cease , but is only impeded , when concretions themselves begin to obtain a sensible quiet ; nor is produced anew , but only acquires more liberty , when concretions begin to be moved : we may thence justly infer , that just so much motive force is now , and ever will be in the world , while it is a world , as was in the first moment of its creation . which really is the same with that rule of des cartes princip . philosoph . part . . art . ● ) deum esse primariam omnis motus caussam ; & candem semper motus quantitatem in universo perseverare . and hence may we extract these notable conclusions . ( ) that , because look how much one atom , being impacted ag●inst another , doth impel it , just so much is it reciprocally impelled by it ; and so the force of motion ●oth neither increase , nor decrease , but in respect of the compensation made , remains always the very same , while it 〈◊〉 executed through a free space , or without resistence : therefore , when con●retions , likewise mutually occurring , do reciprocally impel each other ; they are to be conceived , to act upon , or suffer from each other , so , as that , if they encounter with equal forces , they retain equal motions on each side , and if they encounter with unequal forces , such a compensation of the tardity of one , is made by the supervelocity of the other , as that accepting both their motions together , or conjunctly the motion still continues the same . which also is the same with that third law of nature , registred by des cartes ( princip . philosoph . part . . art . ● . ) quod unum corpus , alteri fortiori occurrendo , nihil amittat de suo motu : occurrendo , vero minus forti , tantum amittere : quantum in illud transfert . ( ) that forasmuch as atoms constantly retain their motive virtue even in the most compact and hard concretions ; therefore can there be no absolute qui●t in nature : the atoms uncessant striving for liberty , causing perpetual commotions in all things , though those commotions be intestine and insensible as we have often said . which considered , heraclitus seems to have been more reasonable , in his denial of all quiet , but to the dead ( apud plutarch ▪ . placit . . ) than most have hitherto allowed : he understanding by the dead , not only animals deprived of life , and consequently of motion ; but also all other things dissolved , since then , and only then , the intestine commotions of their component particles , or atoms ▪ cease . ( ) that motion is not only much more natural than quiet , in the g●●eral ▪ but also always natural , in respect of its original , forasmuch as it proceeds from atoms ▪ which are moved by their own nature , or essentia gravi●● ▪ and ●ometimes violent , but ever so only at second hand , or from the nature of concretions , as they moved with a certain repugnancy . and this rule hath also is moved per accidens , because it is an accident to him ; and likewise his soul is moved by accident , because it is only a part of him . again , when he teacheth , that whatever is moved , is moved by another ; that ought to be understood of that thing , which is moved per se : for , from hence it is , that when in the series of particular movents , he would have us to come at length to one first movent , which is immoveable , or which is not moved by any other ; we are to understand that primum movens to be immoveable per se , since it may be moved per accidens . thus , when a stone is moved by a staff , the staff by the hand of a man , the mans hand by his soul ; the soul , indeed , is the first movent and immoveable : but , understand it to be so , per se , because it is at the same moment moved per accidens , i. e. when the hand , arme , and whole body , which contains it , is moved . moreo●er , he declares , that whatever is moved per se , is moved juxta naturam , according to nature ; such as he affirms that only to be , which is endowed with a soul : yet will he not admit , that what is moved by another , should always be moved praeter naturam , praeternaturally ; but sometimes unnaturally ( as a stone , when it is thrown upward ) and sometimes naturally ( as a stone , when it falls down again . ) now , if you hereupon demand of him , what that is , which makes a stone fall down again ; he shall answer , that what moves it downward , per se , is the generant it self , or that which first produced the stone : and that which moves it downward , per accidens , is that which removes the impediment or obstacle to its descent , as the hand of a man , or other thing supporting the stone . and , if you again enquire of him , what is the difference betwixt the upward and downward motion of a stone , how one should be violent , and the other natural , since , according to his own assertion , both are caused by another : his return will be , that the difference lies in this , that the stone is not carried upward , of its own nature , but downward ; as having the principle of its descent , inhaerent in it self , but not that of its ascent . if you urge him yet farther ; since the stone hath in it self the principle of its motion , why therefore is it not moved only by it self , but wants another , or external motor ? his answer will be : that there is a twofold principle of motion , the one active , the other passive ; and in the stone is only the principle passive , but in the external motor is the active . when yet it may be farther pressed ; that since according to his own doctrine , the passive principle is the matter , and the active the forme : as to the matter , that cannot be the principle of its motion downward , no more than of its motion upward ; and as for the forme , if that be neither the active principle , nor the passive ( as he will by no means admit ) certainly there can be none . which for him to allow , were plainly to destroy his own great definition of nature , wherein he acknowledgeth it to be the principle of motion . but , alas ! these are but light and venial mistakes , in comparison of those gross incongruities that follow . when aristotle comes to handle the species , or sorts of natural motion , you may remember , that he first distinguisheth natural motion in direct and circular ; and then subdistinguisheth the direct into ( ) that which is from the circumference toward the centre , or from the extrems toward the middle of the world , which he calls downward ; and ( ) that which is from the centre toward the circumference , which he calls upward : assigning the former , or downward motion , only to heavy things , to the earth simply , to water and mixt things , secundum quid ; and the upward be . what then , must that external principle be , as aristotle contends , the very generant of the thing moved ? certainly , that 's highly absurd ; since the generant is absent , and perhaps , long since ceased to be in rerum natura : and nothing either absent , or nonexistent , can be the efficient of a natural action , such as motion is . if you will have , that to be moved by the generant , signifies no more than to receive a virtue or power of moving it self , from the generant ▪ then while you endeavour to save aristotle from the former absurdity , you praecipitate him into a gross contradiction of his own doctrine : for , since the generant it self ought to be moved by its generant , and that again to be moved by its generant , and so upward along the whole series of generants , till you arrive at length at some first generant , from whence that virtue was first derived ; you bring aristotle to allow a first generant , which impugns his fundamental supposition of the eternity of the world. nay , if you admit god to be the author of the first generant , it will then follow , that god must be the cause of this particular motion , and not the first generant , no more than the last . finally , is that the cause , which only removes the impediment to a heavy bodies descent ? neither is that reasonable ; for , as aristotle himself confesseth , such a cause is only a c●use by accident . seeing , therefore , that the downward motion of a heavy body doth not proceed from any intern●l principle , nor from either its generant , or that accidental one , which removes the impediment to its descent , in the supposed capacity of an external : let us proceed to enquire , whether there be not some other external cause , whereupon we may reasonably charge that effect . which that we may do with the more both of order and plainness ; it is requisite , that we first remember , how philosophers constitute dive●s sorts of violent , or externally-caused motion . empericus ( ● . advers . physicos . ) makes distinct species thereof , viz. pulsion , traction , elation , depression . and aristotle sometimes superads a fifth , namely collision ; sometimes disallowing empericus his division , affirms that the species of motion , made by an external principle , are traction , pulsion , vection , and volutation : upon good reason reducing elation and depression to either traction or pulsion ; forasmuch as a body may be elevated , or depressed by either ●raction or pulsion . but , yet he hath left us rather a confusion , than logical discrimination of the species of violent motion ; for , collision and pulsion are one and the same thing ; and vection may be performed either by pulsion or traction , insomuch as the thing movent doth not forsake the thing pulsed , or drawn , but constantly adhaereth unto it : and as for volutation ; it is both pulsion and traction at once , as may be easily conceived by any man , who seriously considers the manner thereof . nay , traction it self may be justly reduced to pulsion ; forasmuch as the movent , which is said to draw a thing , doth , indeed , nothing but impel it , by frequently reiterated small strokes , either directly toward it self , or to a lateral region : and yet notwithstanding , for pla●nness sake , and the cleerer demonstration of our praesent thesis , we judge it convenient , to conserve the common notion , and to determine , that all motion impressed upon one body by another , is performed , in the general either when the movent propels the moveable from it self , or attracts it toward it self . for , albeit the movent sometimes propels the thing moved from another body , or attracts it to another ▪ yet can it not possibly do that ▪ but it must , at the same time , either avert it , in some measure , from , or adduce it toward it self . nevertheless , it is not to be denied , but pulsion is always the chie● species ▪ ●nd for that consideration alone is it , that pro●ection ( which is only impul●●on , or , as aristotle emphatically calls it , a more violent motion ) is generall● a●cepted as synonymous to violent motion ; and that philosophers seldo● or never exemplifie violent motion , but in projectills , whether they be projected upward , or downward , ●●anve●sly , obliquely ▪ or any way whateve● ▪ these things considered● 〈◊〉 follows of pure necessity , that the downward motion of heavy bo●●es , being caused ( not by any inte●nal , but ) b● an ●xternal force impressed upon them ▪ must be effected either by impulsion , or by traction . b● impulsion it cannot ; because , in the case of a stone throwneupward , ther● 〈◊〉 nothing external , that can be imagined to impel 〈◊〉 down again ▪ 〈…〉 attained the highest point of its mountee , unless 〈◊〉 should be the 〈◊〉 and i● its descent did proceed from the impul●● ▪ 〈…〉 from below upon the upper part of the stone● 〈…〉 projection of the stone upward , during its ascent , the motion thereo●●ould , in every degree of its remove from the pro●●cient ▪ be accelerated 〈…〉 same proportion , as it s downward motion is accelerated ▪ in ever●●●gree of its descent ; but experience testifies , ●hat ●ts upward motion 〈…〉 and more retarded , in every degree of its remo●● from the projici●●● and therefore it cannot be , that the downward motion thereof should be ●●used , nay not so much as advanced by the aer . which thing ●as●endus 〈◊〉 epist. de proport . qua gravia decidentia a●celerantu● 〈…〉 ●●monstrated ; and we our selves , out of him , 〈◊〉 the article of our 〈◊〉 concerning gravity and levity , in the . book . praecedent . wha● ▪ 〈◊〉 , can remain , but that it must be by attraction ? 〈◊〉 ▪ because no other attractive force , which might begin and continu● 〈◊〉 downward motion of a stone , can be imagined ▪ unless it be that mag●●●●que virtue of the earth , whereby it draws all terrene bodies to an 〈…〉 it self , in order to their , and its own better conservation ▪ 〈…〉 conclude , that the cause of the downwar● motion o● all 〈…〉 , is the magnetique attraction of the earth . nor need we adferr other ●●guments , in this place , to confirm this position● in respect we have 〈◊〉 made it the chief subject of the sect. of our chap. of gravity 〈…〉 ; whether we , therefore , remit our unsatisfied reader . from the cause of 〈◊〉 downward motion of heavy bodies , let us advance to the acceleration 〈◊〉 them , in every degree of space , through which 〈…〉 reason , why we should at all enquire 〈…〉 upward mo●ion of light bodies , in every degree 〈…〉 as we know of no man , but aristotle , that 〈…〉 motion of fire , and aer is slower in the beginning ▪ and gradually 〈◊〉 and swifter in the progress . and so short was 〈…〉 proving that his s●●gular conception , by experiment , as he ought ; 〈…〉 assumed ●t upon 〈◊〉 credit of only one poor argument , which is 〈◊〉 . 〈…〉 and other things of the like light and aspiring 〈…〉 caelo . cap. . ) were extruded and impelled 〈…〉 descending and crouding toward the 〈…〉 force , as some have contended ; and we●e 〈…〉 spontaneous tendency of their own inhaerent 〈…〉 moved more swiftly in the beginning , and mo●e slowly 〈…〉 their motion ▪ but fire , and aer are more 〈…〉 beginning 〈…〉 more and more swift in the progress of their assent ; therefore are they not moved upward by the extrusion and impulsion , but spontaneously , or by their own levity . and to confirm his minor proposition , that fire and aer are accelerated in every degree of their assent ; without the suffrage of any experiment , he subjoyns only , that as a greater quantity of earth is moved downward more swiftly , than a less ; so is a greater quantity of fire moved upward more swiftly than a less : which could not be , if either of them were impelled , or moved by an external force . but , this is , as the former , meerly petitionary ; for , why should not a greater quantity of earth , or fire be moved more swiftly than a less , both being moved ( as we suppose ) by external force , in ●●se the external force be proportionate to the quantity of each ? doubtless , the force of the ambient aer , extruding and impelling flame upward , is alway● so much the greater , or more sensible , by how much more copious the ●●re is ; as may be evinced even from the greater impetus and waving motion of the flame of a great fire : though it cannot yet be discerned , whether that undulous or waving motion in a great flame be ( as he praesume●● more swift and rapid , than that more calm and equal one observed in the flame of a candle . tha● ( you l say ) is enough to detect the incircumspection of aristotle , in assuming , upon so weak grounds , that the motion of light things ascending , is accelerated in the progress , and that in the same proportion , as that of heavy things descending is accelerated : but not enough to refute the position it self ; and therefore we think it expedient , to superad a demonstrative reason or two , toward the plenary refutation thereof . seeing it is evident from experience , that a bladder blown up is so much the more hardly depressed in deep water , by how much neerer it com●s to the bottom ▪ and a natural consequent thereupon , that the bladder , in respect of the aer included therein , beginning its upward motion at the bottom of the water , is moved toward the region of aer so much the more slow●y , by how much the higher it riseth toward the surface of the water , or lower part of the region of aer incumbent thereupon ; and that the cause thereof is th●s , that so much the fewer parts of water are incumbent upon the bladder and aer contained therein , and consequently so much the less must that force of extrusion be , whereby the parts of water bearing downward impel them upward : we may well infer hereupon , that if we imagine that any flame should ascend through the region of aer ; till it arrived at the region of fire , feigned to be immediately above the region of aer ; that flame would always be moved so much the slower , by how much the higher it should ascend , or by how much the neerer it should arive at the region of fire . because fire and aer are conceived to be of the same aspiring nature : and because the same reason holds good , in proportion , for the decrease of velocity in the ascension of flame through the aer , as for that of the decrease of velocity in the ascension of aer , included in a bladder , through water . and , as for aristotles other relat●ve assertion , that a greater quantity of earth is moved more swiftly downward , than a less ; manifest 〈…〉 without ▪ nay 〈…〉 e●perience doth 〈…〉 inhaerent in bodies account●● heavy , and that every body must therefore ●all down so much the mor● swiftly and violently , by how much the more of gravity 〈◊〉 possesseth . h●ving thus totally subverted aristotle● erroneous tenent ▪ that the 〈◊〉 of l●ght bodies ascending , is accele●a●●d in every degree of their a●●●ntion : it follows , that we apply our selves to the consideration of the 〈◊〉 of t●e motion of heavy bodies 〈◊〉 in every degree 〈…〉 descention . whe●ein the first obs●●v●abl● o●●urring , i● the 〈…〉 , or that it is so , which is easily proved from hence , that in all ages 〈…〉 been observed , that the motion of 〈◊〉 things descendent ▪ 〈…〉 the beginning , and grows swifter and swi●●●● 〈◊〉 toward th● end ▪ 〈…〉 that in fine 〈◊〉 becomes highly rapid ▪ 〈…〉 that the 〈…〉 or impression made upon the earth ▪ 〈…〉 down from 〈◊〉 high , is always so much the greater or strong●● by h●w much the 〈◊〉 ●he place is from which it ●ell . the second , 〈◊〉 the 〈◊〉 or cause of that velocity encreasing in 〈…〉 which though enquired into by many of the ancients , seem● 〈…〉 been 〈◊〉 by none of them . for ( ) albeit aristotle 〈◊〉 was so wary ▪ as 〈…〉 explicate his thoughts concerning it ; y●t ●o●h hi● great 〈◊〉 simpli●●●● tell us ● in comment . . ) that it was h●s opinion ▪ that a 〈…〉 other thing ●alling from on high , is corrobo●●ted [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] a totalitate propria , and hath its species ma●● mor● and mo●● 〈◊〉 ▪ as it comes neerer and neerer to its proper 〈◊〉 ▪ and so 〈…〉 degree of gravity acceding to it in every ●egree of its 〈◊〉 to the earth , it is accordingly carried more and more sw●ftly . but , 〈◊〉 that simplicius hath not expounded , how the 〈◊〉 ston● can 〈…〉 ▪ how it can be corroborated , or acquire more and more 〈…〉 its species ; or how that additament of fresh ●ravity should 〈…〉 judge you , whether he hath done aristotle 〈…〉 author of that opinion , which instead of 〈◊〉 ●he 〈…〉 much more obscure than afore . besides , we have the 〈…〉 , that a descending body is not carried the more ●w●ftly ▪ by re●so● 〈◊〉 ●ny access or additament of gravity : a stone 〈…〉 ounce 〈…〉 as speedily down , as one of an hundred poun● ▪ ( ) others 〈…〉 as the same simplicius commemorates ) who 〈…〉 the cause 〈…〉 the decrease of the quantity of the aer 〈◊〉 the s●o●● ▪ 〈◊〉 that by how much the higher a stone is , by so 〈…〉 and so much the greater resistence to the motion 〈…〉 much the greater quantity of the aer resisting 〈…〉 consequently the resistence of the aer growing 〈…〉 of the stones descent , the velocity of its 〈…〉 proportion thereunto . and this after 〈…〉 , sinking in deep water ▪ more slowly 〈…〉 neer the bottom . but , though we adm●t , 〈…〉 stone descending ▪ yet we 〈…〉 to m●ke ●ny sensible difference of 〈…〉 and , would you have an argument to 〈…〉 one fathom ; 〈…〉 fall the same 〈…〉 fathoms , observe again with what velocity it passeth the last , or tenth f●thom . this done , consider , sin●e in the latter case , the velocity shall be incompa●ably greater , than in the former ; whether it be not necessary , that th●t great au●mentation of velocity in the stone , while it pervadeth the t●nth fathom of space , must not arise from some other , and more potent c●use , th●n the resistence of the inferio● 〈◊〉 ? for , in both case● , the stone carries the same proportion of weight ▪ and in the lowest f●thom there is the same quantity of aer , and consequently the same measure o● resistence . and , if you weigh the stone , fi●st in some very high place , ●n● afterward in a low , or very neer the earth ; surely , you cannot expect to find●●t heavier in the low place in respect of the lesser quantity of a●r ●ub●ja●ent , than in the high , in respect of the greater quantity of aer there 〈◊〉 it . lastly , as for their argument desumed from the slower sink●ing of weights in deep , than in sh●llow 〈…〉 thereof 〈…〉 same with th●t of the more diffi●ult depression of a 〈…〉 aer , neer the bottom , th●n neer the top of the 〈…〉 explained . ( ) a third ●onceipt there 〈◊〉 ( imputed to hipparchu● , by the 〈◊〉 simplicius ) which comparing the downward motion of a stone , 〈◊〉 by its own proper gr●vity , with the upward motion of the 〈…〉 , caused by an external ●orce impressed upon it by the 〈…〉 infers , that as long as the force imprest praevails over the stones gravity , 〈◊〉 long is the stone carried upward , and that more swiftly in the beginning , because the ●orce is then strongest , but afterward less and less swiftly , because the same f●rce imprest is gradually debilitated , until the stones proper gravity at length getting the upper hand of the force imprest , the stone begins it motion downward ; which is slower in the beginning , because the gravity doth not y●t much praevail , but afterwards grows more and more sw●ft , because the gravity more and more praevails . but this leaves us more than half way short of the difficulty ; for , though it be reasonable to assume , that a certain compensation of velocity is made in both 〈…〉 . that the decrease of velocity toward the end of the upward motion , is made up again by the encrease of velocity toward the end of the downward , and that in proportion to the degrees of space : yet forasmuch as the motion of a stone falling down is constantly accelerated , not only after it hath been projected upward , but also when it is only dropt down from some high place , to which perhaps it was never elevated , but remained there from the beginning of the world , as it often happens in deep mines , the earth ●●derneath the stones neer the surface of it being 〈…〉 cannot the stones gravity , gradually praevailing over the imprest force , be , as hipparchus concludes , the cause of it● 〈…〉 of its descent . these reasons thus deluding our curiosity , let us have 〈…〉 formerly asserted position , that all terrene 〈…〉 are attracted by the magnetique virtue of the earth . 〈…〉 that the magnetique virtue of the earth is 〈…〉 afar off : and thereupon infer , that the 〈…〉 therefore more rapid neer the earth , than far from 〈…〉 took virtue seems to be greater , and so the 〈…〉 truth neerer the stone 〈…〉 and plausible to our first thought : but insatisfactory to our second . for , if it were so , then ought the celerity of the stones motion , in one fathom neer the earth , to be the same whether the stone be let fall from the altitude of only one fathom , or from that of , , an fathoms , when we exactly measure the spa●● of time , in which it pervades the one fathom neer the earth , in the former case , and compare it with that space of time , in which it pervades the same lowest fathom , in the latter . it may be farther observed , that , whether a stone be let fall from a small , or a great altitude , the motion thereof for the first fathom of its descent , is always of equal velocity , i. e. it is not more nor less swift for the first fathom of its descent from the altitude of an ●● fathoms , than from the altitude of only two fathoms : when yet it ought to be more swift for the first fathom of the two , than for the first of the hundred , if the attraction of the earth be more vehement neer at hand , than far off ; in a sensible proportion . we say , in a sensible proportion ; because , forasmuch as the magnetique rays emitted from it , are diffused in ●ound from all parts of the superfice thereof , and so must be so much the more dense , and consequently more potent , by how much less they are removed from it : therefore must the attraction be somewhat more potent at little than at very great distance ; but yet there is no tower or praecipice so high , as to accommodate us with convenience to experiment , whether the power of the earths magnetique rayes is greater , to a sensible proportion , in a very low place , than in a very high . and yet notwithstanding , nothing seems more reasonable than to conceive , that since the magnetique attraction of the earth is the true cause of a stones downward motion , therefore it should be also the true cause of the continual increment of its velocity , during that motion . but how it should be so ; there 's the knot . which that we may undo , let us first resume our former supposition ( in the . sect. of our chap. of gravity and levity . ) that a stone were situate in any of the imaginary spaces ; considering that in that case it could not of it self be moved at all : because , holding no communion with the world ( which you may suppose also to be annihilated ) there could be , in respect thereof , no inferior place or region , whereto it might be imagined to tend or fall ; nor could it have any repugnancy to motion , because there would be no superior region , to which it might be conceived to aspire or mount . then let us suppose it to be moved by simple impulsion , or attraction , toward any other part of the empty , or imaginary spaces ; and without all doubt , it would be moved thitherward , with a motion altogether equal or uniform in all its parts : because there could be no reason , why it should be more slow in some parts of its motion and more swift in others , there being no centre , to which it might approach , or from which it might be removed . suppose farther , that , as the stone is in th●t motion , another impulse , equal in force to the former , whereby it was first moved , were impressed upon it ; then , assuredly , would the stone be moved forward more swiftly than before , not by reason of any affection to tend to any centre , but because the force of the 〈◊〉 impulse persevering ▪ the force of the second impulse is superadded unto it , and the accession of that force must so corroborate the former , as to augment the velocity of the stones motion . and hence comes it , that to move forward a bo●● already in motion , doth not only prolong , but accelerate the motion the●●of . imagine moreover , that a third impulse were ●●●●ntinent●y superadded to the second ▪ and then would the motion be yet more swift than before ; the encrease of velocity of necessity still responding to the multiplicity of impulses made upon the body moved . this may be familiar to our conceptions , from the example of a globe set upon a plane ; which may be emoved from its place with a very gentle impulse , and if many of those impulses be repeated thickly upon it , as it moves , the motion thereof will be so accelerated , as at length to become superlatively rapid . which also seems to be the reason , why a clay bullet is discharged by the breath of a man , from a trunck , with so great force , as to kill a pidgeon at , or yards distance : the impetus or force impelling the bullet , growing still greater and greater , because in the whole length of the trunck there is no one point , in which some of the particles of the mans breath successively flowing , do not impress fresh strokes , or impulses upon the hinder part of the bullet . the same also may be given , as the most probable cause , why long guns carry or shot , or bullet farther than short ; though yet there be a certain determinate proportion to be observed betwixt the diametre of the bore , and the length of the barrel or tube , as well in truncks , as guns : experience assuring , that a gun of five foot , musket bore , will do as good execution upon fowl , with shot , and kill as far , as one of ten foot , and the same bore ; and consequently that those gunners are mistaken , who desire to use fowling pieces of above , or foot long ; these considerations premised , we may conceive , that when a stone first begins to move downward , it then hath newly received the first impulse of the magnetique rays emitted from the earth : and that if after the impression of that first impulse , the attraction of the earth should instantly cease , and no nevv force be superadded thereunto from any cause vvhatever ; in all probability , the stone vvould be carried on tovvard the earth vvith a very slovv , but constantly equal and uniform pace . but , because the attraction of the earth ceaseth not , but is renevved in the second moment by an impulse of equal force to that first , vvhich began the stones motion , and is again renevved in the third moment , in the , , , &c. as it vvas in the second , therefore is it necessary , that because the former impulses , impressed are not destroyed by the subsequent , but so united as still to corroborate the first , and all combining together to make one great force ; vve say , therefore is it necessary , that the motion of the stone , from the repeated impulses , and so continually multiplied impetus or force , should be more swift in the second moment , than in the first ; in the third , than in the second ; in the fourth , than the third , and so in the rest successively ; and consequently , that the celerity should be augmented in one and the same tenour , or rate , from the beginning to the end of the motion . the third thing considerable in this downward motion of bodies , is the proportion , or rate , in which their celerity is encreased . concerning this , we know of no enquiry at all made by any one of the ancients ; only hipparchus , as hath been said , thought that in the general , the increment of velocity in things falling down , was made in the same reciprocal proportion , as the velocity of the same things projected upward . but , about yeers past , one michael varro , an eminent mathematician ( in tract . de motu . ) depending meerly upon reason ; would have the problem to be thus solved . what is the ration , or proportion of space to space , the same is the ration of celerity to celerity ; so that if a stone falling down from the heigth of four fathoms , shall in the end of the first fathom acquire one degree of velocity , 〈…〉 ●nd of the second two , in the end of the third three , in the end of 〈◊〉 fourth four : it will be moved twice as swiftly in the end of the second ●athom , as in the end of the first , thrice as swiftly in the end of the 〈◊〉 , and four times as swiftly in the end of the fourth● as of the first . 〈◊〉 this proportion is deficient , first in this ; that though the increment of ●●lerity , or of its equal degrees , may be compared with the equal mo●●nts or parts of space : yet can it not be compared also with the equal ●●ments o● parts of time , without which the myst●ry can never be 〈◊〉 . and therefore aristotle did excellently well , in defining 〈◊〉 ▪ and slow , by time ▪ determining that to be swift , which 〈…〉 deal of space in a little time ; and on the contrary ▪ that to be 〈…〉 pervading a little of space in a great deal of time . again , 〈…〉 suppose the theorem to be explicable by equal moments of times 〈…〉 such as are the respites or intervals betwixt the pulses of our 〈…〉 and that a stone falling down doth pervade the first fathom of 〈…〉 the first moment : then , if it pervade the second fathom twice as 〈◊〉 as the first ( as varro conceives ) it must necessarily follow , that 〈◊〉 second fathom must be pervaded in the half of a moment ; if the 〈◊〉 ●hom he percurred thrice as swiftly as the first , it must be pervaded in 〈◊〉 third part of a moment ; and if the fourth fathom be percurred four times 〈◊〉 swiftly as the first , it must be pervaded in the fourth part of a 〈◊〉 and , because , if you conjoyn the half , third , and fourth part of a mome●●●ou shall have a whole moment with one twelfth part of a moment ; it 〈◊〉 necessary , that in the second moment , three fathoms ( very neer ) must 〈◊〉 percurred : which indeed is very far from truth . for ▪ because , if we 〈◊〉 after the same method , so that the fifth fathom be percurred in the 〈◊〉 part of a moment ; the sixth in the sixth part of a moment , 〈◊〉 so successively ; out of these fragments of time we shall not be 〈◊〉 to make up another whole moment , until it be after the stone hath 〈◊〉 the eleventh fathom , or thereabout ; and so in the third moment 〈◊〉 fathoms shall be pervaded , nor shall we again be able to make up 〈…〉 who le moment , until after the stone hath pervaded the fathom 〈…〉 so in the fourth moment , it shall pervade fathoms , nor shall 〈◊〉 able to make up another complete moment , unt●● after the stone 〈…〉 , neer upon , the fathom , and so in the fifth moment , fath●●s shall be percurred , &c. so that proceeding 〈…〉 , neer upon ; you shall consequently , in a very short time , 〈…〉 it up to immensity : as is manifest from the short progress 〈…〉 numbers , . , , , , , &c. which is impugned by easie 〈…〉 , and not defensible by any reason whatever . this the brave 〈◊〉 well considering , and long labouring his subtle and active 〈…〉 explore a fully satisfactory solution of this dark 〈…〉 most happily to set up his rest in this . first , he defines motion 〈◊〉 accelerated to be that , which receding from quiet , doth acqu●●● 〈…〉 of celerity , not in equal spaces , but equal 〈…〉 upon grounds partly experimental , partly 〈…〉 that the moments , or equal degrees of cele●●ty 〈…〉 or equal degrees of time , or ( more plain●● 〈…〉 the same proportions as the times ; so that 〈…〉 of time pass during the motion , so many degrees 〈…〉 by the thing moved . that the equal 〈…〉 continently in single moments of time , do encrease in each single moment , according to the progression not of unities , but of numbers unequal from an unity : so that if in the first moment of time , the stone fall down one fathom , in the second moment , it must fall down three fathom , in the third five , in the fourth seven , in the fifth nine , in the sixth eleven , and so forward . and , because those numbers , which they ●●ll quadrate ( viz. one is the quadrate of an unity , fower the quadrate of a binary , nine the quadrate of a ternary , sixteen of a quaternary , and ) are made up by the continual addition of unequal number● ( for , three added to one , make four ; five added to four , make nine ; seven , to nine ▪ make sixteen ▪ nine to sixteen , make twenty five ; eleven to twenty five , make thirty six , &c. ) thereupon he infers ▪ that the aggregates of the spaces percurred from the beginning to the end of the motion , are as the quadrates of the times : i. e. assuming any one particular moment of time , so many spaces are found pervaded in the end of that moment , as are indicated in the quadrate number of the same moment . for example , when in the end of the first moment , one fathom of space is pervaded ; in the end of the second moment , four fathom shall be pervaded ▪ ( viz. three being added to one ) in the end of the third moment , nine fathom ( five being added to four ) in the end of the fourth moment , sixteen fathom ( seven being added to nine ) and so forward : so that , accordingly , the spaces pervaded from the beginning to the end of the motion , are among themselves in a duplicate ration of moments ( as geometricians speak ) or equ●l divisions of time ; or , all one as the quadrates of moments are one to another . galilaeus , we said , herein relyed partly upon experience , partly upon reason . first , therefore , for his experience ; he affirms , that letting fall a bullet , from the altitude of florentine cubits ( i. e. according to exact comparation , feet , par●s measure , and thirty fathom of ours ) he observed it to pervade the whole space , and arrive at the ground , in the space of five seconds , or ten sem●seconds ▪ and according to such a ration , as that in the first semisecond , it fell down one cubi● , in the second semisecond , four cubits ; in the third semisecond , nine cubits , in the fourth sixteen ; in the fifth twenty five ; in the sixth ; in the seventh , forty nine ; in the eighth , sixty four ; in the ninth , eighty and one ; in the tenth the whole hundred . and though the good mersennus afterward found a bullet to pervade the same altitude in a much shorter time ; nay , that in the space of five seconds , a bullet fell down through the space not onely of one hundred and eighty foot , but even of three hundred ▪ i. e. of fifty fathom : yet doth he fully consent , that the acceleration of its motion ariseth exactly according to galilaeos progression by the quadrates of unequal numbers . so as that if in the first semisecond , it descend one semi-fathom ▪ in the second semisecond , it shall descend four semifathoms , in the third sem●second , nine semifathoms , &c. and gassendu● likewise , though he wanted the opportunity of experimenting the thing● from a tower of the like altitude ; found notwithstanding , from different heights , that the proportion was always the same ; as himself at large declares 〈…〉 qua gravia decident . accelerantu●● 〈…〉 you doubt to find it so your self , if in a glass tube , neer upon two 〈◊〉 ●●ng , divided into an hundred degrees , or equal parts , 〈…〉 either cut in , or inscribed upon papers ( after the manner of those usually starcht on to weather-glasses , to denote the several degrees ) and not perpendicularly erected , but somewhat inclining , you let fall a bullet , and exactly observe the manner of its descent , and rate of acceleration . for , heavy bodies are , indeed , moved more slowly in tubes inclined , than in such as are perpendicularly erected ; but yet still with the same proportion of acceleration . secondly , for his reason , it consists in this ; that , if the increment of velocity be supposed to be uniforme ( and there is no reason , which can persuade to the contrary ) certainly , no other proportion can be found out , but that newly exposed : since , with what celerity , or tardity soever you shall suppose the first fathom to be pervaded it is necessary that in the same proportion of time following , three fathoms should be pervaded ; and in the same proportion of time following , five fathoms should be pervaded ; &c. according to the progression of quadrate numbers . this , that great man ioh. baptista ballianus ( whom ricciolus often mentions ( in almagesto novo ) but never without some honourable attribute ) hath demonstrated divers ways in lib. . de gravium motu . ) : but the most plain demonstration of the verity thereof , yet excogitated , we conceive to be this , invented by gassendus . thirdly , we may account the line de for the first degree of velocity acquired in the end of the first time ; insomuch , as the first time ae is not individual , but may be divided into so many instants , or shorter times , as there are points , or particles in the line ae ( or ad ) so neither is the degree of velocity individual , or wholly acquired in one instant ; but from the beginning encreaseth through the whole first time , and may be repraesented by so many lines , as may be drawn parallel to the line de , betwixt the points of the lines ad and ae : so that , as those lines do continually encrease from the point a to the line de ; so likewise doth the velocity continually encrease from the beginning of the motion , and being represented what it is in the intercepted instants of the first time , by the intercepted lines , it may be represented what it is in the last instant of the same first time , by the line de drawn betwixt the two last points of the triangle ade . and because the velocity , thenceforward continuing its encrease , may be again signified , by greater and greater lines continently drawn betwixt all the succeeding points of the remaining lines , db and ec ; hence comes it , that the line fg , doth represent the degree of velocity acquired , in the end of the second moment : the line hi . the velocity acquired in the end of the third moment ; and the line kl . the velocity acquired in the end of the fourth moment . and evident it is from hence , how the velocities respond in proportions to the times ; since , by reason of the triangles of a common angle , and parallel bases , it is well known , that as de are to ea , so fg to ga : hi to ia , and kl to la. thus , keeping your eye upon the figure , and your mind upon the analogy ; you shall fully comprehend , that in the first moment of time , the falling stone doth acquire one degree of velocity , and pervades one degree of space ; that in the second moment of time , it acquires another degree of velocity , which being conjoynd to the former , makes two , and in the mean while three spaces are pervaded ; that in the third moment , it acquires another degree of velocity , which conjoyned to the two former makes three , and in the mean while seven parts of space are pervaded ; and so forward . you shall fully comprehend also , that the celerities obtain the same ration , as the moments of time : and that the spaces pervaded from the beginning to the end of the motion , have the same ration , as the quadrates of the moments of time ; which we assumed to demonstrate , out of gassendus . but still it concerns you to remember , that we here discourse of that motion , which is equally , or uniformly accelerated ; or whose velocity doth continually and uniformly encrease , nor is there any moment of the consequent time , in which the motion is not more swift , than it was in every antecedent moment , and in which it is not accelerated according to the same reason . for , the want of this advertisement in chief , seems to have been the unhappy occasion of that great trouble the learned jesuit petrus cazraeus put gassendus to , in his two epistles , de proportione , qua gravia decidentia accelerantur . and this kindly conducts us to the physical reason of this proportion , in which the velocity of bodies descending is observed to encrease . for wholly excluding the supposition of the aers assistance of the downward motion of a stone , by recurring above , and so impelling it downward ; and admitting the magnetick attraction of the earth to be the sole cause of its descent ; unto both which the considerations formerly alleadged seem to oblige us : it is familiar for us to conceive , that the increment of its celerity , according to the proportion assigned , ariseth from hence . while in the first moment , the earth attracts the stone , one degree of celerity is acquired , and one degree of space is pervaded . in the second moment , the attraction of the earth continuing , another degree of celerity is acquired , and three equal spaces are pervaded : one by reason of the degree of celerity in the mean while acquired , and two by reason of the degree of celerity formerly acquired , and still persevering , as that which is doubly ●equivalent to the new degree in the mean while acquired ; because it is complete and entire from the very beginning of the d moment , but the other is only acquiring , or in fieri , and so not complete till the end of the second moment . then , according to the same ration , in the third moment another degree of celerity is acquired , and five spaces ( equal ) are pervaded ; one by reason of the new degree of celerity in the mean while acquired , and fower by reason of the two former persevering , i. e. two in each moment praecedent , or one of a duplicate aequivalency to the new one not yet complete . then , in the fourth moment another degree of celerity is acquired , and seven spaces are pervaded ; one by reason of the fresh degree in the interim acquired , and six by reason of the three former per●●vering , i. e. two in each praecedent moment . and so of the rest through the whole motion , computing the degrees of encreasing celerity , by the ration of quadrate numbers . now , many are the physical theorems , and of considerable importance , which might be genuinely deduced from this excellent and fruitful physicomathematical speculation ; and as many the admired apparences in nature , that offer themselves to be solved by reasons more than hinted in the same : but , such is the strictness of our method , and weariness of our pen , that we can , in the praesent , make no farther advantage of it , than only to infer from thence the most probable reason of that so famous phaenomenon , the equal velocity of two stones , or bullets , the one of pound , the other of only one ounce weight , descending from the same altitude ; experience constantly attesting , that being dropt down together , or turned off , in the same instant , from the top of a tower ; the lesser shall arrive at the ground , as soon as the greater . for , this admirable effect seems to have no other cause but this ; that the lesser body , as it containeth fewer parts , so doth it require the impulses or strokes of fewer magnetical rays , by which the attraction is made : and such is the proportion of the two forces , as that each moveable being considered with what resistence you please , still is the force in the movent equally sufficient to overcome that resistence , and a few magnetique rays suffice to the attraction of a few parts , as well as many to the attraction of many parts . so that the space being equal , which both are to pervade ; it follows , that it must be pervaded by both , in equal or the same time . provided always , that the two bodies assumed , be of the same matter ; for , in case they be of divers matters , as the one of wood , the other of iron or lead , that may cause some small difference in their velocity . we say , some small difference ; because , if we take two globes of different materials and weights , but of the same or equal diameters , as ( v. g. ) one of lead , the other of wax : we shall be very far from finding , that the heavier will be carried down more swiftly than the lighter , in a proportion to the excess of its gravity . for , if one be ten times heavier than the other ; yet shall not the heavier therefore , both being turned off , in the same instant , arrive at the ground ten times sooner than the lighter : but , at the same time as the heavier , arrives at the ground , from the altitude of fathoms ; the lighter shall come within a foot of the earth ; so far short doth the lighter come of being nine fathoms behind the heavier . and the cause , why the lighter globe of wax , is carried so swiftly , is the same with that , why a bullet of lead of only an ounce weight , is carried down as swiftly as another bullet of pound . and , what though the globe of wax be as great in circumference , as the other of lead , and somewhat greater ; yet seeing still it hath fewer parts to be attracted , it therefore requires fewer magnetical rays to its attraction with equal velocity to the heavier . but , the cause why it is carried somwhat , though very little , slower than the heavier ; is to be derived chiefly from the aer resisting it underneath , the aer being more copious in proportion to the virtue attrahent , in respect of the greatness of its ambite , or circumference : and thence is it , that cork , pith of elder , straws , feathers , and the like less compact , and so more light bodies , fall down much more slowly . from this experiment , and the reason of it , we have an opportunity of observing and easily understanding the distinction of gravity into simple and adjectitious : the former being that , which is competent to a body though unmoved , and whose quantity may be exactly determined by the balance suspending the body in the aer ; the latter being proper only to a body moved , and vanisheth as soon as the body attaineth quiet , and whose measure is to be explored both from the quantity of the simple gravity which the body bears during its quiet , and the altitude from which it falls . thus , assuming two bullets , the one of an ounce , the other of pound , simple gravity , according to the scales ; the adjectitious gravity of the lesser bullet , acquired by the increment of its velocity during its descent , must be less proportionably to its simple gravity , than the adjectitious gravity of the greater bullet , acquired by the increment of its velocity during its descent , in the same time , and from the same altitude : because , the space and time of the descent of both being equal , the proportion of the acquired gravity of each must be respondent to the proportion of the simple gravity of each . so that if in the end of the fall of the lesser bullet of an ounce weight , the adjectitious gravity of it shall amount to ounces : the adjectitious gravity of the greater of pound weight , shall , in the end of its fall , amount to a thousand pound ; nor can the acquired gravity of the lesser ever equal that of the greater , unless it fall from a far greater altitude . here , perhaps , you 'l demand our opinion , concerning that admirable because superlative velocity , which galilaeo and other mathematicians conceive that a bullet would acquire in case it should fall to the ●arth from those vast ( we might have said immense ) heights of the moon , sun , and region of the fixed starrs . of this , therefore , we say in short ; ( ) that , in this case , mathematicians are wont to suppose , that there are the same causes of gravity and velocity in those sublime places , as are observed here with us below , or neer the surface of the earth : and if they be not , certainly our description and computation must be altogether vain and fruitless . for , if the cause of gravity , and consequently of the velocity be the attraction made by the magnetique rays transmitted from the earth ; forasmuch as those magnetique rays must become more rare , and fewer of them arrive at a body , by how much farther it is removed from the earth : though , perchance , a bullet might be attracted down from the region of the moon ( and if so , the motion of the bullet would be very slow , for a good while , in respect of the very few magnetique rays , that could arrive to that great height ) yet from that far greater height of th● region of the fixt stars , a bullet could not be attracted at all , it being impossible that any magnetique ray should be transmitted so far as half way thither . ( ) but , supposing that the magnetique virtue of the earth did extend thither ; and that a bullet , from whence soever falling , should begin its motion with that speed , and proceed according to the same degrees of acceleration , which we observe in a stone , or bullet falling from a very high tower : then must it of necessity acquire that incredible velocity , which our mathematicians describe . to particular ; conceding the distances or intervals betwixt the earth and each of those caelestial orbs , which our modern and best astronomers generally assign ; a bullet would fall from the body , or rather the limbus of the moon , to the earth , in two hours and an half ; from the limbus of the sun , in eleven hours and a quarter : from the region of the fixt stars , in hours and a quarter . and so , if we imagine the earth to be perforated to the centre , since a bullet would fall from the superfice thereof down to the centre , in minutes , or the third part of an hour : the same bullet coming from the moon , would pervade the same space from the superfice of the earth to the centre of it , in one minute and twenty seconds , or the third part of a minute : coming from the sun , it would pervade the same semidiametral space of the earth , in seventeen seconds : and coming from the region of the fixt stars , it would percur the same semidiametral space of the earth , in five seconds . so incredibly great would be the velocity of a bullet falling from such vast altitudes . and this we think sufficient ▪ concerning the downward motion of bodies , accounted heavy . sect . iii. the remnant of our praesent province consists only in the consideration of the upward motion of heavy bodies projected : concerning which the principal enquiries among philosophers are ( ) vvhat and whence is that force , or virtue motive , whereby bodies projected are carried on , after they are separated from the projicient ? ( ) what are the laws of their motion . direct , and reflex ? concerning the first , therefore , we observe , that aristotle ( in . physic . cap. ult . ) and most of his sectators confidently affirm , that a stone thrown out of a sling , an arrow shot from a bow , a bullet discharged from a gun , &c. is moved only by the aer , from the time of its separation from the sling , bow , or gun : and the manner of that mo●ive activity of the aer upon the thing projected , they thus explicate . the aer ( say they ) which is first moved by the projicient , together with the moveable , doth , at the same time , both propel the moveable , and impel the aer immediately beyond it , which being likewise moved , doth in the same manner propel the moveable , and impel the aer immediately beyond it ; and that aer being thus moved , doth again impel both the moveable and the aer next beyond it : and so consequently the next aer impels both the moveable and the next aer beyond it , until the propulsion and promotion being gradually debilitated , and at length wholly overcome , partly by the gravity of the thing moved , partly by the resistence of the occurring aer , the motion wholly ceaseth , and the thing projected attaineth quiet . and that others contend , that the body projected is carryed forward by a force ( as they call it ) imprest ; which they account to be a quality so communicated unto the body projected , from the projicient , as that not being indelible , it must gradually decay in the progress thereof , and at length wholly perish , whereupon the motion also must by degrees remit its violence , and at length absolutely vanish , and the thing projected again recover its native quiet . but , lest we trifle away our praecious moments , in confutin● each of these weak opinions , against which the reason of every man is ready to object many great absurdities , especially such as the praecedent theory will soon advertise him of : let us praesently recur to the more solid speculations of our master gassendus in his epistles ( de motu impresso a motore translato ) and praesenting you the summary thereof , without further delay satisfie your curiosity , and our own debt of assisting it . first we are to determine , that nothing , remaining it self unmoved , can move another . for , since our discourse concerns not the first cause of all motion , god , whose power is infinite , who is in all places , who can , only by the force of his will , create , move , and destroy all things ; manifest it is , that nothing finite , especially corporeal ( and such only hath an interest in our praesent consideration ) can move another thing , unless it self be also moved at the same time : as plato well observed in his saying , neque est dissicile modo , sed etiam plane impossibile , ut quidpiam motum imprimere , sine quapiam sui commotione , valeat : ( in timaeo . ) and the reason is this ; whatever doth move , doth act ; and e converso , whatever doth act , doth move ; action and passion ( as aristotle , . physic . ) being the same with motion . again , the movent and moveable ought to be together , or to touch each other , because , whether the movent impel , attract , carry , or ●owle the moveable : necessary it is , that still it should impress some certain force upon it : and force it can impress none thereupon , unless by touching it . and though it doth touch it , yet if it discharge no force of motion upon it , i. e. remain unmoved it self : there shall be only a meer contact reciprocal , but no motion , and as the one , so shall the other remain unmoved . therefore , that the one may move the other : it ought to have that vigour or motion first in it self , which it doth impress upon the other : since if it have none , it can give none . even sense demonstrates , that by how much more vehement motion the movent it self is in , at the instant it toucheth the moveable , by so much the farther doth it always propel the same : and thence our reason may necessarily infer , that the movent must it self be in some small motion , in the same instant it gives a small motion to another . moreover , though aristotle ( in . physic cap . ) subtly distinguisheth three things in motion , viz. the 〈◊〉 ut quod , as ( v. g. ) a man , the movens ut quo , as a staff : and the mobile , as a stone : and thereupon magisterially teacheth , that the stone is moved , and doth not move ; that the staff is moved , and doth move : that the man doth move , and is not moved : yet is it not ●●ident , how far short he comes , of thereby demonstrating the immobility of the first movent , to which he praetended . for whereas he urgeth , that otherwise we must proceed to infinity ; that binds not at all : because the movens ut quod , the man is moved by himself : and sense declares , that the man must move his arm , or hand together with the staff , which if you suppose not to be the movens ut quo , ( the stone b●●ng not moved thereby ) but the mobile it self : is not the movent it self ●●so moved ? suppose also , that the mans arme , or hand is the move●● 〈◊〉 quo , nay if you please , that his whole body , or the muscles , or nerve , or spirits , are the movens ut quo , and deriving the motion from his very soul , suppose that to be the movens ut quod : yet truely can you not ●●●ceive , that the soul , it self remaining immote , doth move the arm , o●●and . nor is the soul it self then moved onely by accident ( as whe●● marriner is carried by the motion of his ship ) but also per se , as w●●● the mariner moves himself , that he may move the oar , that it may move the ship , in which himself is carried . for , as a ship , in a calm sea , ●ould not be moved it self , nor the mariner be moved with it , by accid●●● ▪ in case the mariner himself wanted motion , whereby to impel his ship● so neither would the body be moved , nor the soul be moved therew●●● by accident , unless the soul be first agitated within , with a motion wh●●●by the body is moved . conclude , therefore that nothing can be 〈◊〉 , but the projicient must not only touch it , either immediately , ●●mediately by some instrument ; but also propel it with the same 〈◊〉 , wh●●●with it self is , in the same instant , moved . it is moreover ●●●●ssary , that the movent be moved , not only in a point , or so far as that point of space , in which it first toucheth the moveable : but also that a while cohaering unto the moveable , it be moved along with it : so as we may well conceive them to be made , by that cohaesion , as it were one and the same body , or one entire moveable , pro tempore ; and consequently , that the motion of both the movent and moveable is one intire motion . for , what motion is in the moveable , so long as it remains conjoyned to the movent , is in a manner a certain tyrocinium , in which the moveable is as it were taught to progress foreward in that way , which the movent hath begun , upward , downward , transverse , oblique , circular , and that either slowly , or swiftly , and according as the movent shall guide and direct it , before its manumission or dismission . thus , when a man throws a stone with his hand , you may plainly perceive , how the motion thereof begins together with that of his hand : and after it is discharged from his hand , you cannot say , that a new motion is impressed upon the stone , but only that the same motion begun in the hand is continued . and , therefore , it seems also very unnecessary to require the impression of any new and distinct force upon the stone projected , by the projicient , which should be the cause of its motion after its dismission : seeing nothing else is impressed , but the very motion to be continued through a certain space ; so that we are not to enquire , what motive virtue that is , which makes the persevering motion , but what hath made the motion , that is to persever . in the moveable , certainly , there is none but a passive force to motion ; nor can the active force be required in any thing but the movent : and should we , with the vulgar , say , that there is an imprest force remaining , for some time , in the thing moved , or projected ; we could thereby understand no other than the impetus , or motion it self . here might we opportunely insist upon this , that motion is impressed upon a thing moved , only in respect , that the thing moved hath less force of resistence , than the movent hath of impulsion : so that the movent , forcing it self into the place of the moveable , compels it to recede , or give way , and go into another place . but it is more material for us to observe ; that when a thing projected is impelled , it is first touched by the projicient only in those parts , which are in its superfice or outside and that those outward parts , being pressed by the impulse , do drive inward or press upon the parts next to them ; and those again impel the parts next to them , and those again the next to them ; till the impulse be by succession propagated quite through the body of the thing projected , to the superficial parts in the opposite side , and then begins the motion of the whole , the parts reciprocally cohaering : as hath been formerly explained , in the example of a long pole , or beam of wood . which being percussed , but with a very gentle or softly stroke , that one end hath all its parts so commoved successively , as that the stroke may be plainly perceived by a man , that lays his ear close to the other end : which could not be if the impulse were not propagated from parts to parts successively , through the whole substance of the beam . to which it is requisite , that we superad this observable also ; that by reason of the force made by contact , and that short cohaesion of the moveable to the movent , there is created a certain tension , or stress of all the parts of it , towards the opposite region : and of that by that means , all the parts of the thing projected , are disposed or conformed as it were into certain fibers , or direct files ; of all which the most strong and powerful is that , which being trajected through the centre of gravity in the thing projected , becomes as it were the axis to all the circumstant ones . our eys ascertain , that unless the centre of gravity be in the middle of the thing projected , or directly obverted to the mark , at which the thing is thrown ; the thing instantly turns it self about , and that part , wherein the centre of gravity is , always goes foremost , and as it were carries the rest of the parts , as that which is the most direct and most tense of all the fibres . and this cannot be effected , but with some ( more or less ) deflection from the mark , at which the force , according to the centre and axis of gravity , was directed ; forasmuch as the centre of gravity , wherein many fibres concur , makes some resistence , and detorting the fibres , inflecteth them another way , and so a new axis is made pro tempore , according to which the direction of all the parts in their motion afterward is determined . hence is it , that , if you would hit a mark , either with a sling , or stone-bow , you must choose a stone , or bullet of an uniform matter and composition : or , at least , turn the heavier part of the body to be thrown , forward ; because otherwise , it will deflect more or less , to one side or other according to the position and inclination of its centre of gravity . moreover , whether soever the thing projected doth tend , all the fibers constantly follow the direction of the axis , or are made parallels thereunto ; so that as often as the centre is changed , so often doth the axis , so often do all the fibres change their position , and follow the centre . which we insert chiefly in respect of the motion of convolution , or turning of a thing projected immediately after its dismission ; and of the curvity of that line , which is thereby described , whether ascending , or descending . but these are onely transient touches , or hints ; that we might easily intimate , why a motion once imprest , is continued rather this way , than that : and why feathers , sponges , and the like light and porous bodies , are incapable of having quick and vehement motions imprest upon them ; because they consist of interrupted fibres , and such as are not dirigible with the centre of gravity . here we ask leave , once more to have recourse to that useful supposition of a stone situate in the immensity of the imaginary spaces . we lately said , as you may remember , that if a stone placed in the empty extramundane spaces , should be impelled any way , the motion thereof would be continued the same way , and that uniformly or equally , and with tardity or celerity proportionate to the smartness or gentleness of the impulse , and perpetually in the same line ; because in those empty spaces it could meet with no cause , which by diversion might either accelerate , or retard its motion . nor ought it to be objected , that nothing violent can be perpetual ; because , in this case , there could be no repugnancy or resistence , but a pure indifferency in the stone to all regions , there being no centre , in relation whereunto it may be conceived to be heavy or light. and , therefore , the condition of the stone would be the very same , as to uniformity and perpetuity of motion , with that of the caelestial orbs ; which being obnoxious to no retardation , or acceleration , but free from all repugnancy internal , and resistence external , constantly and inde●inently maintain that circular motion , which was , in the first moment of their creation , imprest uopon them , by the will of the creator ; and that toward one part , rather than any other . let us now farther consider ; seeing that if upon some large horizontal plane you should place a smooth globe , and then gently impel it ; you would observe it to be moved therupon equally and indefinently , till it came to the end thereof : why may you not lawfully conjecture , that if the terrestrial globe were of a superfice exquisitely polite , or smooth as the finest venice glass ; and another small globe as polite were placed in any part of its superfice , and but gently impelled any way , it would be moved with constant uniformity quite round the earth , according to the line of its first direction ; and having rowled once round the earth , it would , without intermission again begin , or rather continue another circuit , and so maintain a perpetual circulation upon the surface of the earth ? especially , since there is no difficulty 〈◊〉 discourage that conjecture ; forasmuch as look how many parts of the small globe , during the motion thereof , tend toward the centre of the earth , just so many are , at the same time , elevated from it : so that a full compensation being made in all points of the motion , the same cannot but perpetually continue , and in the same equal tenour , there being no declivity , whereby it should be accelerated , no acclivity , wherby it should be retarded , no cavity , whereby after many accurses and recurses , or reciprocations , it should be brought at length to acquiesce . moreover , in order to our grand scope , let us suppose , that the space , through which a stone should be projected , were absolute inane , or such as the imaginary spaces ; and then we must acknowledge , that it would be carried in a direct and invariate line , through the same space , and with an uniforme and perpetual motion , until it should meet with some other space , full of magnetique rayes , aer , or some other resisting substance . but , here with us , in the atmosphere , because no space is inane ( sensibly ) but replete as well with aer , as with millions of magnetique rayes transmitted from the earth ; and so a stone projected must encounter them in every point of space through which it moves : therefore is it , that it cannot be moved either in a direct line , or equally , or long . for , since multitudes of magnetique rayes must necessarily invade and attach it , as soon as it is discharged from the projicient ; though at first setting forth it break through them , and so is scarce at all deflected : yet because more and more magnetique rayes freshly lay hold of it in every part of space , renew the attraction , and so more and more infringe and weaken the force of its motion ; hence comes it , that in the progress it doth by little and little deflect from the line of direction , moves slower and slower , and at length sinking down to the earth , thereon attains its quiet . hereupon , when men shall demand , what is that cause , which weakens and at last quite destroys the virtue impressed upon a thing projected ; rightly understanding , by the virtue imprest , the motion begun by the projicient , and continued by the projectum : the answer is manifest ; viz. that it is the attraction of the earth , which first opposeth , after gradually refracteth , and in fine wholly overcometh the motion imprest , and so determineth the projectum to quiet . hence also may we learn , that all motion once impressed , is of it self indelible , and cannot be diminished , or determined , but by some external cause , that is of power to repress it . this considered , you may please to observe , that through the atmosphere , or spaces circumvironing the terrestrial globe , being so possessed by the aer and swarms of magnetique rayes , no body can be projected in an absolute direct : or perfectly streight line , unless perpendicularly upward or downward . for , if the projection be made either obliquely , or parallel to the horizon ; the projectum suddainly begins to deflect from the mark at which it was aimed , and so describes not a streight , but crooked line . not that the deflection or curvity is sensible , at a small distance , especially if the motion be vehement , such as that of an arrow shot from a bowe , or bullet discharged from a gun : but , that in every point of space , and time , the thing projected is attracted somewhat downward ; and there is the same reason for its deflection in the first , as there is for its deflection in the second , third , fourth , or any following point of space , and instant of time , though the greater opposition of the force imprest makes that deflection less at the first . nor ought it to incline us to the contrary , that archers and gunners frequently hit the mark , at which they levelled , to some certain distance : because , that distance is commonly such , as that the deflection therein is not sensible , though it be sometimes an hairs-breadth , two , three , or four , sometimes an inch below the mark . further you may observe , that when a stone is projected , or a bullet shot upward , yet not p●●pendicularly , but obliquely ; the motion thereof is to be considered , not as simply perpendicular , or simply horizontal , but as mixed , or composed of an horizontal and perpendicular together : of a perpendicular , forasmuch as the altitude thereof may be measured by a perpendicular line ; of an horizontal , forasmuch as it is made according to the horizon , and the latitude thereof may be taken by the plane of the horizon . but , because by how much the more it hath of the perpendicular , so much the less it hath of the horizontal ; so that the altitude of it may amount to fifty feet , and the latitude not exceed one foot : therefore is it manifest , that the crooked line described by this compass motion , cannot be circular ; and galilaeo ( dialog . . ) hath demonstrated that the line is parabolical , or such as geometricians describe in the ambite of a cone , when they so intersect it obliquely from one side at the base , that the motion of the intersection is made parallel to the other side left whole , for the area of each resegment is the geometricians parabola : and the crooked ambite of the area , is a parabolical line , and frequently taken for the parabola it self . we remember also , how galilaeo , upon consequence , and among other remarkables doth observe ; that of all projections , made by the same force , the longest , and in that respect the most efficacious , is that , which is made to an half-right angle , or by aiming at the forty fifth degree of altitude ; in respect of the more prolix parabola which is described by the pr●jectum , aimed at that altitude : since at all other altitudes the parabola must be shorter ; the superior altitudes being less , and the inferior more open than is requisite . now this composition of a perpendicular and horizontal motion may be most conveniently demonstrated unto you , thus . being in a ship , under sayl , if you hold a ball in your hand ; the motion of the ball will be onely horizontal , viz. that , whereby the ship doth carry you , your hand , and the ball in it . if the ship stand still , and you throw the ball directly upward ; the motion of the ball will be onely perpendicular : but if the ship be moved , at the same instant you throw the ball upward ; then will the motion thereof be compound , partly perpendicular , partly horizontal . for , the ball shall be carried obliquely , and describe a parabolical line , in which it ascends and again falls down again ; and in the mean time , it shall be promoved horizontally . the perpendicular alone , your self may discern with your own eye : because , the horizontal is common both to the ball and your eye , and when as well the ball , as your eye is promoved , therefore doth it always appear imminent over your eye , and in the same perpendicular : but , for the horizontal , he onely can deprehend it , who stands still on the shoare , or another ship not carryed on at the same rate , as that wherein you are . herein there occur two things , not unworthy our admiration . the one is , that though there be two divers forces or motions impressed upon the ball , at the same time : the one from the vibration of your arm , the other from the horizontal translation of the ship : yet doth neither destroy the other , but each attains its proper scope as fully , as if they were impressed apart . for , the ball ascends as high , when the ship is moved forward , as when it stands still : and whether it describe a direct , or a semiparabolical : and again , it is as much promoved horizontally , when you divert it upward by projection , as when you hold it still in your hand and so it be carried onely by the motion of the ship : and consequently whether the motion thereof describe a direct line , or a whole parabola . onely this you are to note : that a greater force is required to the projection of a ball from the foot to the top of the mast , when the ship moves forward , than when it lies at anchor : because that semiparabolical line , which the ball must describe in the former case , is shorter than that perpendicular one , which it must describe in the latter : and however the vibration or swing of your arme may seem to you to be equal in both cases , yet is that vibration or force , whereby the ball is carried upward to the top of the mast , when the ship is in motion , really greater than that , whereby the same ball is carried to the same height , when the ship lies quiet : because , in the former case , there is superadded to the force of your arme , the force which is impressed both upon you and your arme ( without your apprehension ) by the motion of the ship . this you shall plainly perceive , if you onely drop down a ball from the top of the mast , without any swing or motion of your arme at all . for , seeing that the ball doth always fall at the foot of the mast , in the same distance from it , as it was in the instant of its dimission from the top ; whether the ship be moved , or quiet : necessary it is , that some force be imprest upon the ball by the motion of the ship , or the the same motion , whereby both the mast it self , and your hand are affected , at the instant of its dimission ; since it must describe a semiparabolical line , longer than that direct one , which it would describe , if it fell down the ship being quiet . and hence comes it , that if you project a ball from the poop to the fore castle of a ship , under sayl , and back again from the fore-castl● to the poop ; you shall impress a greater force upon it , in throwing it from the poop to the fore-castle , than back again from the fore-castle to the poop : because , in the former case , the force or seconding impulse of the ship must be superadded to the force of your arme in projection , and so make it the stronger ; and , in the latter case , the contrary force of the ship doth as much detract from the force of your arme , and so make it the weaker . and though the ball be carried over equal spaces of the deck of the ship , in both cases : yet shall it not be carried through equal spaces in the aer . hence may it be demonstrated , that the space of time which the ball is ascending from the foot to the top of the mast , is equal to that in which it is descending again from the top to the foot . for , were it not so , when the ball is projected in a line perpendicular and parallel to the mast , the ball would not ascend and descend always at the same distance from the mast , but would either desert it , or be deserted by it , the ship being in motion . whence it follows also , that in what proportion the velocity of the ball ascending doth decrease ; in the same proportion doth the velocity of the ball again descending encrease● so that the motion of the ball must be of equal velocity , when it is removed from the plane of the ship , one fathom ascending , or descending , and likewise at the altitude of one foot , ascending or descending . again , forasmuch as the force of your arme , projecting the ball , is still equal ; but the force superadded thereunto by the motion of the ship , may be more or less vehement , according as the s●●p is carried with greater or less speed : thence it follows , that the ●arabolical lines described by the ball , are respectively greater or less , and the motions of it through the aer more or less swift . 〈◊〉 , yet all are performed in equal time ; because the times of them all are equal to the same time , which is due to the simple assent and descent , and with the same proportion of parts . the other , which deserves our admiration , is this ; that notwithstanding , of the twofold motion composing the oblique one , that which is perpendicular , is unequal , the velocity thereof being as well diminished in the assent , as augmented in the descent , so that ; in equal moments of time , less spaces are pervaded in the assent , and greater in the descent : yet is that motion , which is horizontal , plainly equal in all its parts , or of equal velocity throughout ; so that equal spaces of the horizon are pervaded in equal times . the truth of this is constant from hence ; that if ( the ship being equally moved on , and the ball being projected in a line parallel to the mast ) the foot of the mast shall pervade twenty paces , or an hundred foot of horizontal space : the ball shall be horizontally ( i. e. toward that region , to which the ship tends ) promoved , not more swiftly or slowly in one pace or foot , than in another , but equally in all : for , otherwise , it could not be always imminent over the same part of the ship neer the mast : nor therefore consist in the same line , or distance from the mast : which yet it constantly observes . but this easily deceives , that at the end of the balls ascent , or beginning of its descent , the motion is slowest : but then are we to observe , that the devexity , or conformity of it to the horizon is the greater , as when it comes lower , where the motion is more rapid , the devexity is less , and its conformity to the perpendicular greater : so that the whole inaequability doth consist in the assent and descent , or perpendicular motion of the ball : while in the mean time there is a perfect aequability in its horizontal advance , or promotion . from hence we collect : that since a thing projected is moved unequally , insomuch as it tends upward or downward : and not as it progresseth parallel to the horizon , or ambite of the earth : therefore is it , that the upward and downward motions are both to be accounted violent : but the horizontal , or circular , natural : equality , or uniformity being the inseparable character of natural , and inequality of violent motion . thus far have we treated of that returning or reflex motion of bodies , whereby , being violently projected upward , they revert or fall down again , by reason of the magnetique attraction of the earth : and it now remains onely , that we consider the reasons of that other species of motion reflex or rebounding , whereby bodies , being also violently moved or projected any way , are impeded in their course and diverted from the line of their direction , by other bodies encountring them . concerning this theorem , therefore , be pleased to know , that among all reflexions , by way of rebound or resilition , that is the chiefest , when a body projected , and impinged against another body , is returned from thence directly , or in the same line toward the place , from whence it was projected : which always happens , when the projection is made to right angles , or in regular line , such as that in which a heavy body descends upon an horizontal plane . and all other reflections are in dignity inferior thereunto , as such whereby the thing projected doth not rebound in a direct line toward the same point from whence it was projected , but to some other region by other lines : according as it is projected in lines more or less oblique . because , with what inclination a body falls upon a plane , with the very same inclination doth it rebound from the plane ( especially a globe , and such as is of an uniform matter , and consequently hath the centre of magnitude and that of gravity coincident in the same point ) so that by how much the more oblique the projection is , and how much the less is the angle made of its line with the line of the plane , ( called the angle of incidence ) so much the more oblique is the reflexion made , and so much the less the angle made of its line , with the line of the plane continued ( called the angle of reflexion ) and that so long , as till the line of projection shall become parallel to the plane , and so , no body occurring to or encountring the projectum , no reflexion at all be made . know moreover , that betwixt no reflexion at all , and the least reflexion that is possible , there may be assigned as it were a certain medium ; and that is the emersion or rising up again of a weight appensed to a thread or lutestring , when performing a vibration or swing from one side to the other , it ascends from the perpendicular line , to which by descending it had reduced it self . for , in that case , no ●●●lecting body doth occur , a simple arch is described ; and y●●●here is as a certain procidence or falling down to the lowest point of the arch , so also a certain resilition or rising up again from ●he lowest point of the arch , toward the contrary side . again ▪ having conceived a direct line touching the lowest point of the arch , so as that the weight suspended by a string , may , in its vibration , glance upon it with its lowest extreme , and onely in a point touch the horizontal line ; you shall have on each side an angle mad● from the arch and the line touching it , which is therefore called the angle of contingence : and because geometricians demonstrate● that the angle of contingence , which truly differs from a right line , is less than any rectilinear angle , however acute ; therefore may each of those angles be said to be median betwixt the right line , and the angle either of incidence● or of reflexion , how small soever it be ; and consequently , the emersion of the weight in vibration may as justly be said to be median betwixt the smallest reflexion and none at all . however , this emersion seems to 〈◊〉 the rule of all reflection whatever ; for , as in the vibration of a weight appensed to a string , and describing a simple arch , the a●gle of its emersion is always equal to the angle of its prociden●● : so in projection describing an angular line , the angle of reflection is always ( quantum ex se est ) equal to the angle of incidence ▪ we say , quantum ex se est ; for otherwise , whether it be sensible , or not , because so long as the projectum is transferred , it is a●ways somewhat depressed toward the earth , for the reason formerly alleadged ; thence comes it , that the reflexion can neither be so strong or smart as the incidence , nor make as great an angle , 〈◊〉 arise to as great an altitude . which we insinuate , that we might not insist upon this advertisement ; that the aequality of the angle of the reflexion to that of the incidence , may be so much th● less , by how much the less the projected body comes to a spherical figure , or doth consist of matter the less uniform . for , to attain to that aequality of the angels of incidence and reflexion , necessary it is , that the body projected be exactly spherical , and of uni●orm matter , and so having the centre of gravity , and the centre of magnitude coincident in one and the same point ; as we have formerly intimated : it being as well against reason , as experience , that bodies wanting those conditions should arise to that aequali●● which that we may the better understan● , let us consider , that 〈◊〉 in a globe , or ball falling down , we regard onely that gravity ▪ which it acquires in its descent , from the magnetique attraction of the earth : so in a globe , or ball projected , we are to regard onely that impetus or force , which being imprest upon it by the projicient , supplies the place of gravity , and in respect whereof the centre of its gravity may be conceived to be one with that of its magnitude . let a ball , therefore , be projected directly or to right angles , upon a plane ; and , because , in that case , that fibre must be the axis of its gravity , whose extreme going foremost is impinged against the plane : thence is it manifest , that the repression must be made , in a direct line , along that axis ; the parallel fibres in equal number on each part invironing that axis , and so not swaying or diverting the ball more to one part than to another , by reason of any the least disproportion of quantity on either side . then , l●t the same ball be projected obliquely against the same plane ; and because , in this case , not that middle fibre , which constituteth the axis of gravity , but some one or other of the fibres circumstant about it , must with one of its extreams strike against the plane : therefore is it necessary , that that same fibre be repressed by that impulse , and by that repression compelled to give backward toward its contrary extream , and thereby in some measure to oppose the motion begun , which it wholly overcome , and so the ball would rebound from the plane , the same way it came , if the fibres on that side the axis of gravity , which is neerest to the plane , were equal in number to that are on the farther , or contrary side of it : but , because those fibres , that are on the farther side , or on the part of the centre and axis , are far more in number , and so the●e is a greater quantity of matter , and consequently a greater force imprest , than on the side neerer to the plane ; therefore doth the begun motion persever , as praevailing upon the repression and renitency of the fibre impinged against the plane , and since it cannot be continued in a direct line , because of the impediment ariseing from the parts cohaerent , it is continued by that way it can , i. e. by the open and free obliquity of the plane . but , this , of necessity , must be done with some certain evolution of the ball , and with the contact of the fibres posited in order both toward the axis and beyond it ; and while this is in doing , every fibre strives to give back , but , because the farther part doth yet praevail over the neerer , therefore doth the neerer part still follow the sway , and conform to the inclination and conduct of the farther , and all the toucht fibres change their situation , nor are they any longer capable of returning by the same way they came , because they no longer respect that part from whence they came . we say , with the contact of the plane by the fibres posited toward the axis and beyond it ; because , since in that evolution or turn of the ball , the extream of the axis toucheth the plane , yet nevertheless no resilition , or rebound is therefore caused , in that instant ; and if there were a resilition , at that time , it would be to a perpendicular , as well the axis , as all the circumstant fibres being erected perpendicularly upon the face of the plane : but the resilition there must be beyond it , because the force of the farther part of the fibres doth yet praevail over that of the neerer . for , the force of the farther part doth yet continue direct and intire ; but , that of the neerer is reflected , and by the repression somewhat debilitated : and therefore , the resilition cannot be made , until so much of repression and debilitation be made in the further part , as was made at first in the neerer . and that must of necessity be done , so soon as ever the plane is touched by some one fibre , which is distant from the axis as much beyond , as that fibre , which first touched the plane , is distant from the axis on this side : for , then do the two forces become equal , and so one part of the fibres having no reason any longer to praevail over the other , by counter inclination , the ball instantly ceaseth to touch the plane , and flies off from it , toward that region , to which the axis and all the circumstant fibres are then , i. e. after the evolution , directed . now , because the ball is , after this manner , reflected from the plane , with the same inclination , or obliquity , with which it was impinged against it ; it is an evident consequence , that the angle of its reflexion must be commensurable by the angle of its incidence : and that each of them must be so much the more obtuse , by how much less the line of projection doth recede from a perpendicular ; and contrariwise , so much the more acute , by how much more the line of projection doth recede from a perpendicular , or how much neerer it approacheth to a parallel with the plane . from these considerations we may infer two observables . the one , that the oblique projection of a globe against a plane , is composed of a double parallel , the one with the perpendicular , the other with the plane : for , the globe at one and the same time , tends both to the plane , and to that part toward which the plane runs out forward . the other , that nature loseth nothing of her right , by the reflexion of bodies ; forasmuch as she may nevertheless be allowed still to affect and pursue the shortest , or neerest way : for , because the angle of reflexion above the plane , is equal to that angle , which would have been below the plane , in case the plane had not hinderd the progress of the line of projection beyond it , by reason of the angles equal at the vertex , as geometricians speak ; therefore , is the reflex way equal to the direct , and consequently to the shortest , in which the ball projected could have tended from this to that place . here , to bring up the rear of this section , we might advance , a discourse , concerning the aptitude and ineptitude of bodies to reflexion ; but , the dulness of our pen with long writing , as well as the confidence we have of our readers collective abilities , inclining us to all possible brevity , we judge it sufficient onely to advertise , that what we have formerly said , concerning the aptitude and ineptitude of bodies to projection , hath anticipated that disquisition . for , certain it is , in the general , that such bodies , which are more compact , cohaerent , and hard , as they may be , with more vehemence , and to greater distance , projected : so may they , with more vehemence , and to greater distance rebound , or be reflected ; provided , they be impinged against other bodies of requisite compactness , cohaerence , and hardness . and , the reason , why a tennis-ball doth make a far greater rebound , than a globe of brass , of the same magnitude , and thrown with equal force ; is onely this , that there is not a proportion betwixt the force imprest by the projicient , and the gravity of each of them ; or betwixt the gravity of each , and the resistence of the plane . which holds true also concerning other bodies , of different contextures . conclusion : ingenious reader , i have kept you long at sea , i confess , and ( such was the unskilfulness of my pen , though steered , for the most part , according to the lines drawn on those excellent charts of epicurus and gassendus ) often shipwrackt your patience . but , be pleased to consider , that our way was very long and taedious ; insomuch as we had no less than the whole of that vast and deep ocean of sublunary corporeal natures , to sayl over : that our passage was full of difficulties , as well in respect of those sundry rocks of incertitude , which the great obscurity of most of those arguments , whose discovery we attempted , inevitably cast us upon ; as of those frequent mists and foggs , which the exceeding variety of mens opinions , concerning them , surrounded and almost benighted our judgement withal : and chiefly , that if by the voyage your understanding is brought home not only safe , but inriched , though in the least measure , with that inestimable wealth , the knowledge of truth , or what is so like to truth , as to satisfie your curiosity as fully ; as i have reason to congratulate my self , for the happiness of my care and industry , in being your pilot , so must you to esteem the adventure of your time and attention compensated with good advantage . and , now you are on land agen , give me leave , at parting , to tell you ; that all the fare i shall ever demand of you , is only a candid sentiment of my good-will and cordial devotion to the commonwealth of philosophy . which , indeed , doth so strongly animate me on to enterprizes of publique utility , though but to those in the second form of scholars ; that i can be well contented , not only to neglect opportunities of temporal advantages to my self , while i am imployed in the study , how to contribute to the intellectual promotions of others ; but also to stand in the number of those active and free spirits , who have , through want of abilities only , miscarried in their well intended endeavours for the benefit of learning ; rather than in the list of those idle , or envious ones , who having more of wit , than of humanity , and wanting nothing but the inclination to do good , have buried their talents , and lest the republique of arts and sciences , to suffer in the want of such means of advancement , as their capacities might easily have afforded unto it . 't is the custom of the multitude , you know , always to estimate the counsel of designs only by their success ; and never allowing for impediments or sinister accidents , to account the goodness of an undertaking to consist wholly in the felicity of its event : but , such is the justice of wisdom , that it consigns a reward to a good intention ; and decrees a lawrel to be planted on his grave , who fals in the generous attempt of any noble discovery , as well as one to be placed on his head , who shall be so much beholding to the favour and assistance of his fortune , as to accomplish it . this i put you in mind of , not out of arrogance , as if i challenged any thing 〈◊〉 due to me , besides a lively resentment of my constant and sincere zeale to the encrease of knowledge ; but , to possess you more fully with the equity of my expectation , which aims at no other reward , but what detraction it self dares not dispute my right unto , and much less tha● what , i presume , your own charity would , if i had referred my self thereunto , have readily assigned me . but , lest i seem to prevent you in your inclination , or to extort that from you by force of argument , which as well your own innate candor , as judicious aequanimity , had sufficiently praepa●ed you to offer me of your own accord ; i resigne you to your peace , and the undisturbed enjoyment of those pleasures , which usually result from the memory of difficulties once overcome : having first assured you , that your benigne acceptance of my services , and pardon of my misfortunes ( so i may call all such errors , whose praecaution was above the power of my humble judgement ) in this voyage ; may prove a chief encouragement to me , to adventure on a second , without which this first must be imperfect ; and that is for a description of the nature of that paradise of the world , that bright shadow of the all-illuminating and yet invisible light , that noble essence , which we know to be within us , but do not understand because it is within us , and cannot understand without it , the humane soul ; and that , so soon as quiet and physick shall have repaired those decays in the weather-beaten vessel of my body , which long sitting , frequent watchings , and constant solicitude of mind have therein made . in the meantime , i conjure you , by your own humanity , to remember and testifie , that in this my conversation with you , you have found me so far from being magisterial in any of the opinions i praesented ; that considering my own humor of indifferency , and constant dubiosity ( frequently professed , but more expresly , in the first chapter of this work , and . art. of the . chap. . book . ) it hath somewhat of wonder in it , that i ever proposed them to others : nor ▪ indeed , can any thing solve that wonder , but my hope●● thereby secretly to undermine that lofty confidence of yonger heads , in the certitude of positions and axioms physiological ; and by my declared scepticism even in such notions , as my self have laboured to assert , by the firmest grounds , and strongest inducements of belief , to reduce them to the safer level of quo magis quaerimus , magis dubitamus . finis . notes, typically marginal, from the original text notes for div a -e art. . the principal sects of the ancient grecian philosophers , only enumerated . art. . the same revived among the moderns , with en●rease . art . who are reduced either to the pedantique or female sect. art. . or , to the assertors of philoso●hical liberty ▪ art. . or , to the renov●tors . art. . or to the electors . art. . the principal causes of the diversity of philosophical sects ; and the chiefest among them , the obscurity of nature art. . the imperfection of our vnderstanding . art. . the irregularity of our curi●s●t● . a paradox . art. . the ambition of alexander in affecting the conquest , less vain then that of many ancient philosophers in affecting the knowledge of a multitude of worlds . art. . a reduction of those philos●phers to four distinct sect● ; respective to their distinct persuasion ▪ and the h●ads o● each sect nominated . art. . the two main pillars on which the ●pinion of a plurality of worlds was anciently erected . art. . the question stated to be concerning the real existence , not the possibility of an infinity of worlds art. . because the supposed infinity of the extramundan spaces , is no imposs●bility . art . because an i●finity of bodies is also possible : as to the omn●potence of god. art. . the error of concluding the esse , from the posse of an inf●nity of wo●lds art. . the first main pillar of a plurality of worlds subverted . art. . the seco●d pillar found sophisticate , and demolished . art. . a plurality of worlds manif●stly r●pugnant to authority divine , art. . an● human. art. . the result of all ; the demonstrati●n of the authors thesis , that this world is thy vniverse . art. . extramundane curiosity , a high degree of madness . art. . body and inanity , the two general parts of the universe . art. . three the most memorable definitions of corporiety extant among physiologists , recounted and examined . art. . four descriptions of the nature of inanity , by epicurus , cleomedes , empiricus , aristotle . art. . their importance extra●ted : and what is the f●rmal or proper notion of a vacuum . art. . the existence of bodies in the world , manifest by sense : whose evidence is perfect demonstration . art. . the distinction of a vacuum into ( ) natural , and ( ) praeternatural : and the one called disseminate , the other coacer●vate . art. . the nature of a disseminate vacuity , explained by the analogy of a heap of corn. art . the first argument of a disseminate vacuity , desumed from the evidence of motion , in general : and aristotles error concerning the essence of place , concisely detected , and corrected . art. . motion demonstrated by sense : and zeno's aenigmatical argument , for an universal quiet , dissolved . art. . the consequution of the argument ( if no vacuum , no motion ) illustrated . art. . an ob●ecti●n , that the lococessi●n of some bodies , d●p●nds on their rarity or por●sity ; no● on a disseminate vacuity : praevented . art. . no beginning of mo●ion , without inani●y inter●persed . art. . a second argument of a vacuity disseminate , collected from t●e reason of r●refaction and condensation . art. . the eminent phaenomen●n of an aero●●l●pe● , or wind-gun , so●ved by a vacuity dis●eminate among the incontiguous ( quoad totas superfi●ies ) parts of aer . art. . experiment of an ae●lipile , or hermetical b●llow● , attesting a vacuity 〈…〉 . art. . experiment of a sulphu●a●e tapor ▪ included in a glass vial , partly filled with water ▪ of the same importa●ce . art . no c●mbu●t●●le in aer : and so the opinion of the ari●●ot●leans , that the extincti●n of flame impris●ned , is to be charged on the defect of aer , for its sustenta●ti●n ; grosly erroneous . art. . a fourth singular and memorable experiment of the authors , of yce at the nose of a large reverberatory furnace , charged with ignis rotae ; evidencing a vacuity inter spersed in the aer . art. . an inference from that experiment ; that aer , as to its general destination , is the common recepta●y of exhalations . art. . a second ●llation , that the aer doth receive exhalations at a certain rate , or definite ▪ proportion ; which cannot be transcended without prodigious violence . art. . the existence of inane incontiguities in the aer , confirmed by two considerable a●guments . art. . that water also contains vacuola , empty spaces ; demonstrated . art. . from the experiment of the dissolution of alum , halinitre , sal ammoniac , and sugar , in water formerly sated with the tincture of common salt art. . the verity of the lord 〈…〉 , that a repeated 〈◊〉 not rhu●barb 〈…〉 a virtue 〈…〉 a simp●e 〈…〉 , in equal quantity : and why . art. . why two drachms of antimony impragna●e a pint of wine , with so strong a vomitory faculty , as two ounces . art. . why one and the same menstruum●ay ●ay be enriched wi●h v●rious tinctures . art. . two other arguments of a vacuity diss●minate inferrible from ( ) the difference of bodies in the degrees of gravity : ( ) the calefaction of bodies by the penetration of igneous atoms into them . art. . the experiments vulgarly adduced to prove no vacuity in nature , so far from denying , that they confess a disseminate one . art. . the g●and difficulty of the c●u●e of the aers restitution of it self to i●s natural ●ontexture , after ra●efaction and condensation , ●atisfied in brief . art. . what is conceived by a coacervate vacuity : and who was the inventor of the famous experiment of quicksilver in a glass tube , upon which many modern physiologists have erected their perswasion of the poss●bility of introducing it . experientiam apponam , cusus inven●ionem etsi 〈◊〉 qui alii ambitiosi●s 〈…〉 tamen mihi con●●at , 〈◊〉 à torricellio , 〈…〉 art. . a 〈◊〉 description of the exp●riment , and 〈◊〉 rate 〈◊〉 . art. . the authors reason , for his selection of only six of the most considerable phaenomenae to explore the causes of them . art. . the first cardinal difficulty . art. . the desert space in the tube argued to be an absolute vacuum coacervate , from the impossibility of its repletion with aer . art. . the vacuity in the desert space , not praevented by the insinuation of aether . art. . a parad●● , ●hat nature doth not abhor all vacuity , per se ▪ but only ●x accidenti , or in respect to fluxility . art. . a second argument against the repletion of the desert space by aether art. . the vacuity of the desert space , not praevented by an halitus , or spiritual efflux from the mercury : for three convincing reasons . art. . the auth●rs apostacy from the opinion of an absolute coacervate vacuity in the desert space : in regard of art. . the possibili● of the subingression of light . art. . of the atoms or insensible bodies of heat and cold : which are much more exile and penetrative then common aer . art. . of the magnetical efflux of the earth : to which opinion the author resigns his assent . art. . no absolute plenitude , nor absolute vacui●y , in the desert space : but only a disseminate vacuity . art . the second difficulty stated . art. . two things necessary to the creation of an excessive , or praeternatural vacuity . art. . the occasion of galilaeos invention of a brass cylindre charged with a wooden embol , or sucker : and of torricellius invention of the praesent experiment . art. . the marrow of the difficulty , viz. how the aer can be impelled upward , by the restagnant quicksilver , when there externally wants a fit space for it to circulate into . art. . the solution of the same , by the laxity of the contexture of the aer art. . the same illustrated , by the adaequate simile of corne infused into a bus●el . art. . a subordinate scruple , why most bodies are moved through the aer , with so little resistence , as is imperceptible by sense ? art . the same expeded . art. . a second dependent scruple concerning the cause of the sensible resistence of the aer , in this case of the experiment : together with the satisfaction thereof , by the gravity of aer art. . the state of the third difficulty . art. . the solution thereof in a word . art. . three praecedent positions briefly recognised , in order to the worthy profounding of the mystery , of t●e aers resisting compression beyond a certain rate , or determinate proportion . art. . the aequiponderancy of the external aer , pendent upon the surface of the restagnant mercury , in the vessel , to the cylindre of mercury residuous in the tube , at the altitude of digits : the cause of the mercuries constant subsistence at that point . art . a convenient 〈◊〉 , illustrating and enforcing the same . art. . the remainder of the difficulty , viz. why the aequilibrium of these two opposite weights , the mercury and the aer , is constant to the praecise altitude of d●g●t● : rem●ved . art. . huma●e perspicacity terminated in the exterior parts of nature , or simple apparitions : which eluding our cognition , frequently fall under no other comprehension , but that of rational conjecture . art. . the constant subsistence of the mercury at d●gits , adscriptive rather to the resistence of the aer , then to any occult quality in the mercury . art . the anal●gy betwixt the absolute and respective aequality of weigh●s , of quicksilver and water , in the different altitudes of d●gits and feet . art. . the definite weights of the mercury at d●gits , and water at feet , in a tube of the third part of a digit in diametre ; ●●und to be near upon two pou●d , paris wei●ht . * consul●ndus mersennus , in tract . de mensuris & ponderibus , cap . & 〈◊〉 physicomathemat . p. . art. . quaere , why the aequilibrium is constant to the same point of altitude in a tube of a large concave , as well as in one of a small ; when the force of the depriment must be greater in the one , then the other . art. . the solution thereof by the appropriation of the same cause , which makes the descent of two b●dies , of different weights , aequivelox . art. . the fourth capital difficulty proposed . art. . the full solution thereof , by demonstration . art. . the same confirmed , by the theory of the cause of the mercuries frequent reciprocations , before it acquiesce at the point of aequipondium . art. . the fifth principal difficulty . art. . solved , by the motion of restauration na●ural to each insensible particle of aer . art. . the incumbent aer , in this case , equally distressed , by two contrary forces . art. . the motion of restaurati●n in the aer , extended to the satisfaction of another consimilar doubt , concerning the subintrusion of vvater into the tube ; if superaffused upon the restagnant mercury . art. . a third most important doubt , concerning the nonapparence of any tensity , or rigidity in the region of aer incumbent upon the restagnant liquors . art. . the solati●n thereof , by the necessary reliction of a space in the 〈◊〉 regi●n of lax aer , equal to that , which the hand commoved possesseth in the region of the comprest . art. . a confi●ma●ion of the same reason , by the adaequate example of the flame of a tapour . art. . by the experiment of vrination . * quam ob caussam , corpus h●m●nus ad 〈…〉 nullum incumbentis aquae p●ndus sentiat , lector 〈…〉 hyd●aul●● . 〈…〉 p. ● . art. . by the beams of the sun , entring a room , through some slender crany , in the appearance of a white shining vvand , and constantly maintaining that figure , notwithstanding the agitation of the aer , by wind , &c. art. . by the constancy of the rainbow , to its figure , notwithstanding the change of position and place of the cloud & contiguous aer . art. . helmonts dellrium , that the rainbow is a supernatural meteor ; observed . art. . the sixth and last considerable difficulty . art. . the clear solution thereof , by the great disproportion of weight betwixt quicksilver and vvater . art. . a corollary ; the altitude of the atmosphere conjectured . art. . a second corollary ; the desperate● difficulty of conciliating physiology to the mathematicks : instanced in the much discrepant opinions of galilaeo and mersennus , concerning the proportio● of gravity that aer and vvater hold each to other . art. . the conclusion of this digression : and the reasons , why the author adscribes a cylindrical figure to the portion of aer impendent on the restagnant liquors , in the experiment . art. . the identy essential of a vacuum and place , the cause of the praesent enquiry into the nature of place . art. . among all the quaeries , about the hoti of place ; the most important is , whether epicurus , or aristotles definition of it , be most adaequate . art. . the hypothethesis of aristotles definition . art. . a convenient supposition inferring the necessity of dimensions incorporeal . art. . the legality of that supposition . art. . the dimensions of longitude , latitude , and profundity , imaginable in a vacuum ▪ art. . the g●and 〈◊〉 , objecti●n , that nothing is in a vacuum ; ergo 〈◊〉 dimensions art. . des cartes , and mr. vvhite seduced by the plausibility of the same . art. . the peripa●●ticks reduction of time and place to the general categories of su●stances and accidents , the cause of this epidemick mistake . art. . place , neither accident nor substance . art. . the praecedent giant - objection , that nothing is in a vacuum ; s●abb●d , at a blow . art. . dimensions corporeal and incorporeal , or spatial . art. . the former supposition reassumed and enlarged . art. . the scope and advantage thereof ; viz. the comprehension of three eminent abstrusities concerning the nature of place . art. . the inc●rpor●ety of dimensions s●atial , discriminated from that of the divine essence , and other su●stances incorporeal . art. . this persuasion ▪ of the improduction and independency of place ; praeserved from the suspition of impiety . art. . place , not the immediate superfice of the body invironing the locatum ; contrary to aristotle . art. . salvo's for all the difficult scruples , touching the nature of place ; genuinely ex●●acted from epicurus his 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . art. . aristotles ultimate refuge . art. . the invalidity thereof : and the coexistibility , or compatibility of dimensions corporeal and spatial . art. . the hoti of time more easily conceivable by the simple notion of the vulgar , then by the complex definitions of philos●phers . art. . the generall praesumption that time is corporeal , or an accident dependent on corporeal subjects ; the chief cause of that difficulty art. . the variety of opinions , concerning it : another cause of the difficulty : and epicurus description of its essence , recited and explained . art. . time de●ined to be 〈…〉 by z●no , 〈◊〉 , &c. and thereupon affirmed , by philo , to be only 〈◊〉 to the vvo●ld . art. . aristotles so much magnified definition of time , to be the measure of motion coelestial , &c. perpended and found too light . art. . time , nor substance , nor accident : but an ens more general , and the twin-brother of space . art. . a paralellism betwixt spa●● and time. art. . time , senior unto , and independent upon motion : and only accidentally indicated by motion , as the mensuratum by the mensura . art. . a demonstration of the independence of time upon motion , from the miraculous detention of the sun , above the horison , in the days of ioshua . art. . an objection , that , during the arrest of the sun , there was no time , because no hours ; satisfied . art. . the immutability of time also asserted , against aristotle . art. . the grand quaestion , concerning the disparity of time and eternity ; stated . art. . two praeparatory considerations , touchant the aequivocal use of the word aeternity ; requisite to the clear solution thereof . art. . two decisive positions , thereup●n in●erred , and established . art. . the platoni●ks definition of eternity , to be one everlasting new ; not intelligible , and therefore collusive . art. . their assertors subterfuge , that eternity is coexistent to time ; also unintelligible . art. . our ecclesiastick doctors , taking sanctuary in the exod. for the authorizing of their doctrine , that the praesent tense is only competent to god , and so that eternity is one permanent instant , without fusion or succession : not ●●cure from the rigour of our demonstra●ion . art. . the objective praesence of all things at once , to the divine in e●●ect , no wayes impugned by our contradiction 〈◊〉 the doctors theory . art. . no● the immutability of the divine nature ; against aristotle . art. . coronis . notes for div a -e art. . the right of the authors transition from the incorporeal to the corporeal part of nature : and a series of his subsequent speculations ▪ art. . bodies generally distinguished into principles and productions , with their scholastick denominations and proprieties . art. . the right of atoms to the attributes of the first matter . art. . their sundry appellations allusive to their three eminent proprieties . art. . two vulgarly pass●nt derivations of the word , atom , exploded . art. . who their inven●or : and who their nomenclator . art. . their existence demo●strated . art. . th●● nature , in her dissolution of 〈◊〉 , doth des●end to 〈◊〉 partic●es . art. . that ●he 〈…〉 to 〈◊〉 . art. . 〈…〉 the term of ex●olu●ility . art. . a second argument of their existence , drawn from that of their antitheton , inanity . art. . a third , hinted from the impossibility of the production of hard bodies , from any other principle . art. . a fourth , from the constancy of nature in the specification and determinate periods of her generations . art. . the cognation of this theorem , to the argument of the immediately praecedent chapter . art. . mag●i●ude divi●●●le by a continued progress through parts either 〈…〉 . art. . the use of that distinction in the praesent . art. . the veri●y of the thesis , demonstrated . art. . two detestable absurdities , inseparable from the position of infinite parts in a continuum . art. . aristotles sub●erfuge of infinitude potential ▪ art. . found openly collusive . art. . a second subterfuge of the stoick ; art. . manifestly dissentaneo●s to reaso● . art. . the absurdities , by empiricus , charged upon the supposition of only finite parts in a continuum . art. . the sundry inc●ngruities & inconsistenc●s , by the modern anti-democritans , imputed to the suppos●tion of insectility . art. . the full derogation of the 〈◊〉 all together , by o●e single resp●nse ; that the minimum of atomists is not mathematical , but ph●sical , contrary to their praesumption . art. . a seeming d●lemma of the adversary , expeditely evaded . art. . a digression , stating and determining that notable quaestion , whether geomet●ical dem●nstrations may be conveniniently trans●f●●red to physical or sensible quantity ? art. . the introduction , hinting the two general assumptions of the chapter . superbissimo furore ambitiosus nominis aristoteles , in philos●phorum principes est deba●cha●us , uno ●ue incendio congestas trigintae sex seculis tot sapientiae divitias absumpsit ; & si quae voluit superesse funeri , ea omnium ●udib●i● , dicteriisque lacessenda tradidit p●steris , dum in optimorum bona invectus , ab●cissis perditisque sapientiae statu●rum capitibus , suum imp suit singulis : ut magn●nas , in democrit . script . elench . ex plinio in p●ae●at . ad d. vespanianum imp. art. . demo●itus & epicurus vindicated from the absurd admission of inanity to be one principle of generables . art. . atoms not inconsistent with , because the principles of the four vulgar elements . * accipitur pro igne●seu aethere , quem dictum anaxagoras censuit , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , ab ●rendo . art. . the dissent of the ancients , about the number of elements . art. . no one of the four elements sufficient to the production of either any of the other three , or of any compound nature . art. . the four elements , not the prot●principle of concretions . art. . a●oms discriminated from the h●m●●omerical principles of anaxagoras . art. . the principal difficulties urged against the hypothesis of atoms , singularly solved ▪ art. . a recapitulation of the praemises , i●troductory to the verification of the praesent thesis . art. . the no●able opinions concerning the c●mposition of a 〈◊〉 art. . a physical 〈◊〉 cannot cons●●● of points m●thema●●●●l ▪ art. . n●t of parts and points mathematical , united . art. . no● of a simple e●tity before divisi●n 〈…〉 of indivisibles art. . a second apodictical reason , de●umed f●om the nature of union , evincing that atoms are the first and catholick principle of concretions . art. . an ob●ection praevented . art. . the reason of the authors superc●ssion of all other arguments of the like importance . art. . the two links connecting this to the praecedent chapter . art. . the general proprieties of atoms : and the inseparability of each , demonstrated . art. . the resistence of atoms , no distinct propriety ; but pertinent to their solidity or gravity . art. . the specifical proprieties of atoms . art. . by the magnitu●e , is meant the parvity of atoms . art. . a consideration of the grossene●s of our senses , and the extreme 〈◊〉 of natu●e , in her operations , pr●paratory to our conjectural apprehension of the exigu●ty of her materials , 〈◊〉 . art. . the incomprehensible subtility of nature , argued from the art●fice of an exquisite wat●h , contrived in a very narrow room . art. . the vast multitude of sensible particles , & the vaster of elemental atoms , contained in one grain of frankinsense ; exactly calculated . art. . the dioptrical speculation of a handworm , discovering the great variety of organical parts therein , and the innumerability of their component particles . art. . a short digressive descant upon the text of pliny , touching the multiplicity of parts in a flea ; hinting the possible perspicacity of reason . art. . the exility of atoms , conjectural from the great diffusion of one grain of vermillion dissolved in water . art. . the same , inf●rrible from the smal quantity of oil depraedated by the flame of a lamp , in a quarter of an hour . art. . the microscope of great use , in the discernment of the minute particles of bodies : and so advantageous to our conjecture , of the exility of atoms . art. . an epitome of all that directly concerns the figures of atoms in general canons . art. . the first canon , explained and certified . art. . the di●e●sity of figures in atoms . evi●ted fr●m the sensible dissimilitude of individuals , as well animate , a● 〈◊〉 . art. . a singular experiment , antoptically ▪ demonstrating the various configurations of the minute particles of concretions . art. . a variety of figures in atoms , necessary to the variety of all se●sibles . art. . the second canon , explained and certified . art. . the third can●n , explained , & re●uted . art. . two introductory observables . art. . the motion of atoms , according to the general distinction of the ancients , two-fold ; viz. natural , and accidental : & each of these redivided into two different species . art. . the summary of epi●urus figment , of the perpendicular mo●ion of atoms , without a common centre . art. . his declinat●●y natural motion of atoms , excused ; not justified . art. . the genuine sense of ●pi●arus , in his distinction o● the reflex mot●on of atoms , into ec plaga , & 〈◊〉 concu●●●●ne . art. . the several conceptions of epicurus , about the perpetual motions of atoms . art. . th● perpetual in●u●e●ude of atoms , even in compact concretions , ad●●●●rated in 〈◊〉 lea● . art. . the same more sensibly exemplified , in the spirit extracted from mercury , tin , and sublimate . art. . the mutab●lity of all concretions , a good argument of the perpetual intestine commotion of atoms , in the most adamantine compositions . art. . what we are to explode , and what retain , in the opinion of epicurus , touching the motion of atoms . notes for div a -e art. . an introductory advertisement ; of the obscurity of many things to reason , which are manifest to sense : and of the possibility , not necessity of the elementation of concret●●ns , and their sensible q●alities , fr●m the principles prae●ua●ed . art. . the authors definition of a quality , in general : and 〈◊〉 exposition of dem●critu● mysterious text , conc●r●ing the creation of qualities . art. . the necessary deduction of qualities from naked or vnqualified principles . art. . the two primary events of atoms , viz. order and 〈◊〉 , associated to their three essential proprieties , viz. magnitude , 〈◊〉 , and 〈◊〉 ; sufficient to the origination of all ●●alities . art. . the necessity of assuming the magnitude and motion of atoms , together with their order and situation , as to their production of qualities , evicted by a double instance . art. . the figure , order and 〈…〉 concretions , alone sufficient to the caussation of an indefini●e variety of qualities from the 〈…〉 . art. . the 〈◊〉 exemplified in t●e 〈…〉 , on the waves ●f the sea art. . 〈…〉 example . art. . the accension of heat , from concretions actually c●●d , upon a m●er transposition of their 〈◊〉 : particles , exe●plifies in ●●ndry chy●●cal experiments . art. . the generation of all kinds of sensible qualities in one and the same concretion , from the variegated positions of its particles : evidenced in the example of a putrid apple . art. . the assenting suffrage of epicurus . art. . the visible images of objects , substantial : and either corporeal emanations from the superficial parts of concretions ; or light it self , disposed into contextures , consimilar to the figure of the object . art. . the position of their being 〈◊〉 , derived from 〈◊〉 ; and p●●ferred to the 〈…〉 species visible . art. . epicurus text concerning the same . art. . the faithful exposition thereof . art. . the contents thereof reduced to heads art. . the e●isten●e of images vis●ble , certified by autoptical demonstration . art. . epicurus opinion , of the subst●ntial●●● 〈◊〉 images visi●le ▪ 〈…〉 art. . the 〈…〉 : and art. . 〈…〉 art. . the grand 〈◊〉 of alexander , that a continual efflux of substance must minorate the 〈◊〉 of the most solid 〈◊〉 . art. . 〈…〉 . art. . the 〈◊〉 o● images 〈◊〉 reduced to some 〈…〉 art. . 〈…〉 . art. . by exemp●●fying in the numerous round films of wax , successively derep●ed from a wax 〈◊〉 by the flame thereof , in the space of an hour : and art. . in the innumerable films of oyl , likewise successively delibrated , by the flame of an ellychnium , or match , perpendicularly floating in a vessel of equal capacity with solomons bra●en sea , in ●he space of hours . art. . by the analogy betwixt an ●dorable & visible species . art. . the manner and reason of the production of visible images ; according to the hypothesis of epicurus . art. . the celerity of the moti●n of visible images , reasoned ; and compared to that of the light of the sun. art. . the translation of a moveable from place to place , in an indivisible p●int of time , impossible : and why ? art. . the facility of the abdu●tion , or a●olation of images visible , from solid concretions ; solved by the spontaneous e●silition of their superficial atoms : and the sollicitation of light , incident upon them . art. . that objects do not emit t●●ir visible images , but when illustrated : a conceit though paradoxic●l , yet not improbable . art. . visible images systatical , described ; and distinguisht from apostatical ones art. . their existence assured , by the testimony of diodorus siculus : and art. . damascius , together with the autopsy of kircher . art. . kirchers description of that famous apparition at rhegium , called morgana rheginorum : & art. . most ingenious investigation of the causes thereof . art. . his admirable artifice , for the exhibition of the like a●real representation , in imitation of nature . art. . the reason of vision , according to the opinion of the stoicks . art. . of aristotle . art. . o the phythagoreans . art. . of empedocles . art. . of plato . art. . o epicurus . art. . of mons. des cartes . art. . the i●genuity of 〈◊〉 conceit , acknowledged : but the solidity ●●dubitated art. . the opinion of epicurus , more satisfactory , then any other : because more rational , and less obnoxious to inexplicable difficulties . art. . the two most considerable difficulties opposed to epicurus position , of the incursion of substantial images into the eye . art. . that the superfice of nobody is perfectly smooth : evicted by solid reas●n , and aut●psie . art. . that the visible image doth consist of so many rayes as there are points designable in the whole superfice of the object : and that each ray hath its line of tendency direct , respective to the face of that particle in the superfice , from which it is emitted . art. . that the density and vnion of the rayes , composing the visible image , is greater or less ; according to their less , or greater elongation from the object . art. . that the visible image is neither total in the total medium ; nor total in every part thereof : but so manifold as are the parts of the medium from which the obj●ct is discernable . contrary to the aristoteleans . art. . paradox ▪ that no man can see the same particle of an object , with both eyes at once ; nay , not with the same eye , if the level of its visive axe be changed art. . consectary . that the medium is not possessed with one simple image ; but by an aggregate of innumerable images , deradiate from the same object : all which notwithstanding constitute but one entire image . art. . consectary . that myriads of different images , emanant from different objects , may be coexistent in the aer ; without reciprocal penetration of dimensions , or confusi●n of particles : contrary to the pe●ipateticks . art. . that the place of the visible images ultimate reception , and complete perception ; is the concave of the retina tunica . art. . that the faculty forms a judgm●nt of the conditions of the object , according to the representation thereof by the image , at its impression on the principal part of vision , the amphiblestr●ides . art. . consectary . that the image is the cause of objects apparence of this or that determinate magnitude . art. . consectary . that no image can rep●enish the c●ncave of the retina tunica , unless it be deradiated from an object of an almost hemispherical ambite . art. . why , when the eye is open there is a●wayes pourtrayed in the bottom thereof , some one t●tal image ; whose vario●● parts , are the special●mages ●mages of the several things included in the visual hemisphere . art. . paradox . that the prospect of a shilling or object of a small diametre is as great , as the prospect of the firmament . art. . why an object appears both greater in dimensions and more distinct in parts , near at hand , than far off . art. . why an o●ject , speculated through a conve● le●s ▪ appears both greater and more distinct ; but through a concave , ●e●s and more confused : than when speculated only with the eye . art. . digression . what figur'd perspicils are convenient for old : and what for purblind persons . art. . that to the di●udication of one of two ob●ects , apparently equal , to be really the greater ; is not required a greater image : but only an opinion of its greater distance . art. . des cartes opinion , concerning the reason of the sights apprehending the distance of an object : art. . unsatisfactory ; and that for two considerations . art. . and that more solid one of gassendus ( viz. that the cause of our apprehending the distance ●f an object , consisteth in the c●mparation ●f the 〈◊〉 things 〈◊〉 ●●wixt the o●ject and the 〈◊〉 , by the rati●nal facu●●● ) embraced and corrobo●●ted art. . paradox . that the same object , speculated by the same man , at the same distance , and in the same degree of light ; doth alwayes appear greater to one eye , than the other art. . a ●econd paradox . that all men see ( distinctly ) but with ●ne eye at once : contrary to that eminent optical axiom ▪ that the v●sive axes of both eyes concurr and unite in th● o●j●ct . art. . the three degrees of vision , viz. most perfect , perfect , and imperfect : and the verity of the paradox restrained only to the two former degrees . art. . a research into the reason of the different effects of convex and concave glasses , as well dioptrical , as catoptrical . art. . a corollarie . hinting the causes , why an elliptical concave reflects the incident rayes , in a more acute angle , than a parabolical : and a parabolical than a spherical . art. . a consectary . why a plane perspicil exhibits an obj●ct in genuine dimen●io●s ; but a convex , in amplified , and a concave , in minorated . art. . a recapitulation of the principal arguments precedent : and summary of the subsequent . the ●●x muscles ▪ viz. the d●●ect , as the . depr●ment , 〈◊〉 , abducent . and oblique , as the circumactors , or lovers muscles art. . why the situation of an object is perceived by the sight . art. . the same illustrate by an experiment . art. . why the moti●n and quiet of ob●ects ●re d●scerned by the sight . art. . why 〈◊〉 images imita●e the motions of t●e●r arti●pes o● o●iginals . art. . w●y the right●ide ●ide of a c●toptrical image respects the l●ft of its exemplar . and why two catoptrick glasses , confrontingly posited , cause a r●stitution of the parts of the image to the natural form. art. . the argument duely acknowledged to ●e superlatively difficult , i● not absolutely a●atalept●cal . art. . the sentence of arist●tle , concerning the nature of colours : and the comment●●y of scal●ge● thereup●n . art. . the opinion of plato . art. . of the pythagorean and stoi●k . art. . of the spagyrical philosophers . art. . the reason of the 〈…〉 , and election of democritus and epicurus judg●●ent , touching the genera●i●n of col●u●s . art. . the text of epicurus , fully and faithfully expounded . art. . a paradox that there are no colours in the dark . art. . a familiar experiment , attesting the verity thereof . art. . the constancy of all artificial tinctures , dependent on the constancy of disposition in the superficial particles of the bodies that wear them . art. . that s● generally magnif●ed distinction of colors into inh●rent , and meerly apparent ; redargued of manife●t c●ntrad●ction . art. . the emphat●●al , or evan●d colo●rs , created by 〈◊〉 ; n● less r●al & 〈◊〉 , than the ●ost 〈◊〉 ti●ctures . art. . corollary . the reasons of emphatical colours , appinged on bodies objected , by a prism . art. . the true difference of emphatical and durable colour● ▪ 〈◊〉 . art. . no colour formally in●●erent in objects ▪ but onl● 〈◊〉 ▪ or 〈◊〉 c●●●rary to the constant 〈…〉 . art. . 〈…〉 ●arther ▪ ●indi●ated from difficulty , by the 〈…〉 pra●cede●● 〈…〉 o● the a●●mists . art. . the nativity of white ; or the reason of its percep●ion by the sight art. . black , a meet privation of light. art. . the genealog● of all intermediate color ▪ art. . the causes of the sympathy & antipathy of some colours . art. . the intermistion of small shadows , among the lines of light ; absolutely necessary to the generation of any intermediate colour . art. . two eminent problems concerning the generation and transposition of the vermillion and cae●ule , appinged on bodies by prismes . art. . the solution of the former : with a rational conjecture of the cause of the blew , apparent in the concave of the heavens . art. . the solution of the later . art. . the reasons , why the author proceeds not to investigate the causes of compound colours in particular . art. . he confesseth the erection of this whole discourse , on simple conjecture : and enumerates the difficulties to be subdued by him , who hopes to attain an apodictical knowledge of the essence & causes of colours . art. . des cartes attempt to dissolve the chief of those difficulties ; unsucsessful : because grounded on an unstable hypothesis . art. . the clasp , or ligament of this , to the praecedent chapter . art. . the authors notion of the rays of light. art. . a parallelism betwixt a stream of wat●r exsilient from the cock of a cistern , and a ray of light emanant from its lucid fountain . praeconsiderables . art. . light distinguisht into primary , secondary , &c. art. . all light debilitated by reflection : and why . art. . an example , sensibly demonstrating the same . art. . that light is in perpetual motion ; according to arist. art. . light , why corroborated , in some cases , and debilitated , in others , by refraction . corollary . why the figure of the sun , both rising & setting , ap●ears rather elliptical , than sphaerical . art. . paradox . that the proportion of solary rayes reflected by the superiour aer , or aether , toward the earth , is so sma●l , as not to be sensible . art. . that every lucid body , as lucid , doth emit its rayes sph●erically : but , as visible ; pyramidally . art. . that light is invisible in the pure medium . art. . the necessity of the authors confirmation of the f●●st praeconsiderable art. . the corporiety of light , demonstrated by its j●st attributes : viz. locomotion . resilition . refraction . coition . disgr●gation igniety . art. . aristotles definition of ligh● , a meer ambage , and incomprehensible . art. . the 〈◊〉 of light imp●rts not the coexistence of two b●dies in one place : contrary to the peripatetick . art. . nor the motion of a b●dy to be instantane●us . art. . the invisibilit● of ●ight in the limpid medium , no argument of its immateriality : as the peripatetick praesumes . art. . t●e corporiety of light fully consistent with the duration of the sun : contrary to the peripatetick . art. . the in●●nsibility of heat in many lucent b●die● no valid argument against the praesent thesis , that light is flame attenuated . art. . an elogy of the sense of hearing : and the relation of this and the praecedent chapter . art. . the great affinity betwixt vi●ible●nd ●nd audible species : in their representation of the superficial conditions of objects . art. . in the causes and manner of their destruction . art. . in their actin●bolism , or diffusion , both sphaerical and pyramidal . art. . in their certifying the sense of the magnitude , figure , and other● qualities of their originals . art. . in the obscuration ▪ of less by greater . art. . in their off●nce of the organs , when excessive . art. . in th●ir production of heat by multiplication . art. . in their variability , according to the various disposition of the medium . art. . in their chief attributes , of l●comotion , exsiliti●● , ●mpaction , resilition , d●●gregation , cong●egation ▪ art. . the product of the praemises , concerning the points of consent , & dissent of audible and visible species : viz. that sounds are corporeal . art. . an obstruction o● praejudice , from the generally supposed repugnant auth●rities of some of the ancients ; expeded . art. . an argument of the corporiety of sounds . art. . a second argumen● . c●rollar● . art. . the 〈…〉 , where 〈…〉 d●s●ant f●●m ●he sonant a●d rep●●cu●i●●● . corollary . . art. . why concaves yeild the strongest and longest sounds . corollary . art. . the reason of con●urrent echoes , where the audient is near the reflectent , and remote from the sonant . corollary . art. . why echoes mon●ph●n rehear●e so much the fewer syllables , by how much nearer the audient is to the reflecten● . corollary . art. . the rea●on of p●lyph●n echoes . art. . a third argument of the materiality of s●unds : art. . the necessity of a certain configuration in a sound ; inferred from the distinction of one sound from another , by the sense . art. . the same confirmed by the a●ctority of pythagoras , plato , and aristotle . art. . and by the capacity of the most subtle parts of the aer . art. . the reason 〈…〉 . art. . the most subtle particles of the aer onely , the material of sounds . parad●x . art. . one and the sa●e nu●e●ica● v●yc● , not heard by two men , no●●oth ears of one man. art. . a problem not yet solved by any philosopher : viz. how such infi●ite variety of words is formed onely by the various motions of the tongue and lips. art. . a second ( also yet unconquered ) difficulty , viz. the determinate pernicity of the aers motion , when exploded from the lungs , in speech . art. . all sounds created by m●tion , and that either when that intermediate aer is confracted by two solids , mutually resistent ; or when the aer is percust by one solid ; or when a solid is percust by the aer . art. . rapidity of motion necessary to the creation of a sound , not in the first case . art. . but , in the s●●●nd and last . art. . 〈…〉 are of 〈…〉 the d●lation . art. . the rea●on thereof . art. . to measure the velocity of great sounds . art. . sounds , ●oe subject to r●●ardat●●n ▪ ●●om adve●se ▪ no● acceleration , fr●m secun● winds . art. . that all sounds , where the aer is percussed by one solid , are created immed●ately by the frequenc● ▪ not the velocity of motion ; demonstrated . art. . an● likewise , where the ●er is the 〈◊〉 art. . 〈…〉 acute sounds a●i●e from the more , and ●ra●e f●om ●he less 〈…〉 of the aer , demon●●ra●ed . art. . 〈…〉 . art. . the same analytically praesented in scheme . art. . a just and unanswerable exception against the former harmonical hypothesis art. . problem . in what instant , an harmonical sound , resulting from a chord percussed , is begun . art. . that a sound may be crea●ed in a vacuum ; contrary to athanas. kircher in art. magn. cons●ni & d●ssoni lib. . cap. . digression● . art. . why all sounds appear more acute , at large , than at small distance . art. . why cold water falling , makes a fuller noise , than warm . art. . why the voice of a calf is more base than that of an ox , &c. art. . why a dissonance in a base is more deprehensible by the ear , than in a treble voice . art. . that the cognition of the nature of odours is very difficult ; in respect of the imperfection of the sense of smelling , in man : and art. . the contrary opinions of phylosophers , concerning it . art. . some determining an odour to be a substance art. . others , a meer accident or quality . art. . the basis of the latter opinion , infirme and ruinous . art. . that all odorous bodies emit corporeal exhalations . art. . that odours cause sundry affections in our bodies , and such as are config●●able only to substances . ( de compos . medic . secund . loca , cap. . ) art. . that the reason of an odours affecting the sensory , consists only in a certain symbolisme betwixt the figures and contexture of its particles , and the figures and con●epture of the particles of the odoratory nerves . art. . that the diversity of odours depends on the diversity of impressions made on the sensory , respondent to the vari●us figures and contexture of their particles . art. . why some persons abhor those smells , which are grateful to most others . art. . why , among beasts , some species are offended at those scents in which others h●●●ly delight art. . the ge●erati●n and d●ffusion of odours , due only to heat . art. . the differences of odours . art. . the medium of odours . art. . from the superlative acuteness of the sense of tasting , aristotle concludes the cognition of the nature of sapours to be more easily acqui●able , than the nature of any other sensible object : but refutes himself by the many errors of his his own theory , concerning the same . art. . an abridgment of his doctrine , concerning the essence and causes of a sapour , in general . art. . and the differences of sapours , with the particular causes of each . art. an examination and brief redargution of the same doctrine art. . the postp●sit●on thereof to the more verisimilous determination of the sons of h●rmes , who adscribe all sapours to salt. art. . b●t fa● m●re to that most profound and satisfact●ry tenent of democritus and plato ; which deduceth the nativity of sapours from the various figures and contextures of the minute particles of conc●etions . art. . the advantages of this sentence , above all others touching the same subject . art. . the objections of arist. concisely , though solidly solved . art. . that the salivous humidity of the tongue serveth to the dissolution and imbibition of the salt , in all gustables . art. . this chapters right of succession to the former . art. . the dive●● accep●ation of the term , — touching . art. . a pertinent ( though short ) panegyrick on the sense of touching . art. . some tactile qualities , in common to the perception of other senses also . art. . a scheme o● all qualities , or commonly , or properly appertaining to the sense of touching ; as they stand in their several relations to , or dependencies on the univ●●s●l mat●er , atoms : and so , of all the sub●equent ca●ital a●guments to be treated of , in this book . art. . the right of rarity and d●nsity , to the priority of cons●deration . art. . the opinion of those philosophers , who place the reason of rarity , in the actual division of a body into small parts ; and the brief refutation th●reof . art. ▪ a second opinion , deriving ra●ity and density from the several proportions , which quantity hath to its substance ; convicted of i●compre●ensib●lity , and so of insatisfaction . art. . a third , desuming the more and less of rarity in bodies , from the more and less of vacuity intercepted among their particles : and the advantages thereof a●ove all ot●ers , concerning the same . art. . the definitions o● a rare , and of a dense body ; according to the assumpti●n of a vacuity disseminate . art. . the con●rui●y of those d●finitions , demonstrated . art. . 〈…〉 of diff●●ulties , wherein the thoughts of physi●logists have so long wandered ; ●educ●d to a p●int , the genuine state of the 〈◊〉 . art. . that rarity and density can have no other causes immediate , but the more and less of inanity interspersed among the particles of concretions ; demonstrated art. . aristotles exceptions , against disseminate inanity ; neither important nor competent . art. . the hypothesis of a certain 〈◊〉 substance , to rep●enish the pores of bodies , in ra●ifaction ▪ demonstrated insufficient , to s●l●e the difficulty , or demol●●h the epicu●●a● ▪ 〈…〉 vacu●●e : art. . the 〈…〉 understand●ng t●e reason● a●d manner of ●a●i action and c●ndensation , from the 〈…〉 art. . paradox . that the matter of a body , when rarified , doth possess no more of true place , than when condensed , and the conciliation thereof to the praeposed definitions of a ra●e and of a dense body . art. . problem . whether aer be capable of condensation to so high a rate as it is of rarifaction : and the apodictical solution thereof . art. . the opportunity of the present speculation , concerning the causes of perspicuity and opacity . art. . the true notions of a perspicuum and opa●um . art. . that every concretion is so much the more diapha●ous , by how much the more & more ample inane spaces are intercepted among its particles ; caeteris pa●ibus . art. . why glass , though much more dense , is yet much more diaphanous , than paper . art. . why the diaphanity of glass is gradually diminished , according to the various degrees of its cra●●●tude . art. . an apodictical confutation of that popular error , that glass is totally , or in every particle , diaphanous . art. . the contexture of this chapter , with the praecedent art. . that the magnitude of concretions , ariseth from the magnitude of their material principles . art. . the praesent intention of the term , magnitude ▪ art. . that the quantity of a thing , is meerly the matter of it . art. . the quantity of a thing , neither augmented by its rarefaction ; no● diminished by it● condensation ▪ contrary to the aristo●eleans , who distinguish the quantity of a body , fr●m it● substance . art. . the reason of quanti●y , explicable also meerly from the notion of place . art. . the existence of a body , without real ex●ension ; & of ex●●●sion without a b●dy 〈…〉 to nature ▪ yet 〈◊〉 to god. art. aristotles definition of a continuum , in what respect true , and wha● false . art. ● . figure ( physically consid●red ) nothing but the superficies , or terminant extre●● of a body . art. . the continuity of this to the first section . art. . 〈…〉 art. . a considerable exception of the chymists ● viz. that some bodies are dissolved in li●uor● of 〈◊〉 particles ▪ which 〈…〉 art. . why oyle dissociates the parts of some bodies , which remain inviolate in spirit of wine : and why lightning is more penetrative , than fire ▪ art. . smoothness and asperity in concretions , the con●equents of figure in h●●r material principles . art. . the motive virtue of all concretions , derived from the essential mobility o● atoms . art. . 〈…〉 part● art. . what the active faculty of a thing , is . art. . that in nature every faculty is active ▪ none passive ▪ art. . a peripatetick contradiction , assuming the matter of all bodies to be devoid of all activity ; and yet desuming some faculties â tota substantia . art. . that the faculties of animals ( the ratiocination of man only excepted ) are identical with their spirits . art. . the r●●sons of the coexistence of various faculties in one and the same concretion . art. . habit defined . art. . that the reason of all habits in animals , consisteth principally in the conformity and fl●xibility of the organs , which the r●spective faculty makes use of , for the performance of its proper actions . art. . habits , acquirable by bruits : and common not only to vegetables , but also to some minerals . art. . gravity , as to ●●s essence , o● formal reason , very obscure . art. . the opinion of epicurus , good as to the cause of comparative : insufficient as to the cause of absolute gravity . art. . aristotles opinion of gravity , recited . art. . copernicus theory of gravity , insatisfactory ; and wherein . art. . the determination of kepler , gassendus , &c. that gravity is caused meerly by the attraction of the earth : espoused by the author . art. . the ext●rnal principle of the perpendicular descent of a stone , projected up in the aer ; must be either depell●nt , or at●rahent . art. . that the resistence of the superior aer is the only cause which gradually refracteth , and in fine wholly overcometh the imprest force , whereby a stone projected , is elevated upward art. . tha● the aer , distracted by a stone violently ascending , hath as well a depulsive , as a resistent faculty ; arising immediately from its elaterical , or restorative motion . art. . that neverthele●● when 〈…〉 on high in the 〈…〉 no caus● can 〈◊〉 downw●●● motio● , 〈…〉 . art. . a●gument , that 〈◊〉 terraqueous gl●be is endowed with a certain attractive faculty , in order to the detention and retraction of all its parts . art. . what are the parts of the terrestrial globe . art. . a second argument that the earth is magnetical . art. . a parallelisme betwixt the attraction of iron by a l●ad●tone , a●d the attraction of terrene bodies by the earth . art. . that as the sphere o● the loadstones allective virtue is limited : so is that of the earths magnetism . art. . an obiection of the disproportion between the great bulk of a large 〈◊〉 and the ex●●●●y of the supposed magnetique rays of the earth : solved by three w●ighty reasons . art. . the reason of the aequivelocity of bodies , of different weights , in their perpendicular descent : with sundry unquestionable authorities to c●nfirm the hoti thereof . art. . that the centre of the univer●e is not the l●w●st part ●●●reof : nor the centre of the earth ▪ the centre of the world. art. . a fourth a●gument , that gravity is only attraction . art. . why a greater gravity , or stronger attractive force is ●mprest ●pon a piece of iron by a loadstone , than by the earth . art. a ●ifth argument , almost ap●●ictica●● ; that gravity 〈◊〉 the effect 〈◊〉 the earth ●●●●raction . art. . ●word nothing 〈…〉 art. . the connection of this to the immediately precedent chapter . art. . why the author deduceth the first qualities , not from the vulgar elements ; but from the. proprieties of atoms . art. . the nature of heat is to be conceived from its general effect ; viz. the penetration , discussion , and dissolution of bodies concrete . art. . heat defined as no immaterial , but a 〈…〉 art. . that the atoms of heat are capable of expedition or deliverance from concretions . two wayes ; viz. by ev●cation and motion . art. . an vn●ra●us matter , the chief seminary of the atoms of heat : and why . a●● . ● . among ●nctuou● concre●●ons . wh● some ar● more ●asily inflammabl● than others ▪ art. . problem . why the ●otto● of a cald●●n , wherein water is boyling , may be touched by the hand of a man ▪ ●ithout burning 〈…〉 . art. . problem . why lime becomes ardent upon the affusion of water . ●ol . art. . problem . why the heat of lime burning is more vehement , than the heat of any flame whatever . sol. art. . problem ▪ why boyling oyle scalds more vehemently , then boyling water ▪ sol. art. . problem ▪ why metals , melted or made red hot , burn more violent than the fire , that melteth or heateth them . sol. art. . consectary . that , as the degrees of heat , so those of fire are innumerably v●rious . art. . that to the calefaction , combustion , or inflammation of a body by fire ▪ is required a certain space of time ; and that the space is greater or less , according to the paucity , or abundance of the igneous atoms invading the body obiected ; and more or less of aptitude in the contexture thereof to admit them . art. . flame more or less durable , for various respects . art. . consectary . that the immediate and genuine effect of heat , is the disgregation of all bodies , as well homogeneous , as heterogenous : and that the congregation of homogeneous natures , is only an accidental●ff●ct ●ff●ct of h●a● ; contrary to aristotle . art. . the link connecting this section to the former . art. . that cold is no privation of heat ; but a real and positive quality : demonstrated . art . that the adaequate notion of cold , ought to be de●umed from its general effect , viz. the congregation and compaction of bodies . art. . cold , no ●mmaterial ; but a substantial quality . art. . gassendus conjectural assignation of a tetrahedical figure to the atoms of cold ; asserted by sundry weighty considerations . art. . cold , not essential to earth , water , nor aer . art. . 〈…〉 . art. . water , the chief antagonist to fire ; not in respect of its accidental frigidity , but essential humidity ▪ and that the aer hath a juster title to the principality of cold , than either water , or earth . art. . ●roblem ▪ why the breath of a man doth warme , when expi●ed with the m●uth wide open ; & cool , when efflated with the mouth contracted . art. . 〈…〉 the premises . art. . why fluidity and 〈◊〉 are here considered before humidity and 〈◊〉 . art. . 〈…〉 art. . 〈…〉 a firme . art. . fluidity defined art. . wherein the f●rmal rea●on thereof doth consis● . art. . the ●ame ●arther illustrated , by the two●●●ld fluid●ty of metals ; and t●e peculiar reason of each . art. . firmness defined : art. . and d●rived fro● either of ● causes ▪ art. . humidity defined . art. . 〈◊〉 defined . art. . 〈…〉 . art. . problem . why pure water cannot wash out oyle from a clo●● ; which yet wa●er , wherein ashes have been deco●ted , or soap dissolved , easily doth ▪ solut. art. . problem why stains of ink are not to be taken out of cloths , but with ●ome acta liquor ▪ solut. art. . the 〈◊〉 of the chap●er . art. . 〈◊〉 ●nd soft , 〈◊〉 . art. . the difference betwixt a s●ft and fluid . art. . solidity of atoms , the fundament of hardness and inanity , intercepted am●ng them , the fu●dament of softness , in all concretions . art. . hardne●s and so●●nes● , no 〈◊〉 , but m●●rly ●omparative qualities ; as adscriptive to concretions : contrary to aristotle . art. . s●ftness in firme things , deduced from the same cause , as fluidity in fluid one● . art. . the general reason of the mollification of hard ▪ and ind●ration of sof● bodies . art. . the special manners of the mollification of hard : and induration of soft bodies . art. . pr●●lem . why iron is hardned , by being immersed red-hot into cold water ; and its solution . art. . the formal reasons of softness and hardness . art. . the ground of aristotles distinction betwixt formatilia and pre●●ilia . art. . two axioms , concerning & illustrating the nature of softness . art. . flexilit● , ●●actility , ●uctility , &c. de●ived from s●●iness : and rigidity from ●a●dn●●s . art. . problem . what is the c●use of the motion of restoration in flexiles ? and the solut. art. . two obstructions expeded . art. . why flexile bodies grow weak , by over-much , and over frequent bending . art. . the reason of the frequent vibrations , or diadr●ms of lutestrings , & other tractile bodies ; declared to be the same with that of the restorative mot●●n of flexiles : and demonstrated . art. . problem . why the vibrations , or diadr●ms of a chord dist●●ded and percussed , are ae●uitemporane ●us , ●hough not ae●●ispatial : and the solut. art. . problem . why doth a chord of a duple length , perform its diadroms in a proportion of time duple , to a chord of a single length ; both being distended by equal force ; & yet , if the chord of the duple length be distended by a duple fore or weight , it doth not perform its diadroms , in a proportion of time duple to that of the other ; but only if the force or weight distending it , be quadruple to the first supposed : and its solut. art. . the reasons of the vast ductility , or extensibility of gold. art. . sectility and fissility , the consequents of softness . art. . tractility and friability , the consequents of hardness . art. . ruptility , the consequent partly of s●ftness , partly of hardness . art. . problem . why chords d●●●●enced , are more apt to break neer the end● , than in the middle ●nd its solut. art. . that the insensibility of qualities doth not import their vnintelligibility ; contrary to the presumption of the aristotelean . art. . upon what grounds ; and by wh●m , the sanctuary of occult qualities was erected . art. . occult qualities and profest ignorance , all one . art. . the refuge of sympathies and antipathies , equally obstructive to the advance of natural science , with that of igno●e proprieties . art. . thatall attraction , referred to secret sympathy ; and all repulsion , adscribed to secret antipathy , betwixt the agent and patient , is effected by corporeal instruments , and such as resemble those , whereby one body attracteth , or repelleth another , in sensible and mechanique operations . art. . the means of attractions sympathetical , explicated by a convenient simile . art. . the means of abaction and repulsions antipathetical , explicated likewise by sundry similitudes . art. . the first and general ca●ses of all love and hatred , betwixt animals . art. . why things alike in their natures , love and delight in the society each of other : and why vnlike natures abhor and avoid each other . art. . th● 〈◊〉 of qualit●● ( repu●ed ) ●ccult . art. . natures 〈…〉 in 〈◊〉 to the 〈◊〉 or c●●●piration of all parts of the universe ; no occult qual●ty . art. . the 〈…〉 of mans will. art. . the afflux and reflux of the s●a , inderivative from any immaterial influx of the moon . art. . 〈…〉 of 〈…〉 and ●●nversion of ●he 〈◊〉 and other flowers . art. . why garden claver hide●h it s●alk , in the heat of the day . art. . why the 〈…〉 usually 〈◊〉 soon after midnight ; and at break o● day . art. . why shell-fish growe fat , in the full of the moon , and lean again at the new. art. . why the selenites resembles the moon in all not several a●spects . art. . why the 〈…〉 art. . 〈…〉 art. . a corollary . why the granules of gold and silver , though much more pondrous then those of the aqua regis and aqua fortis , wherein they are dissolved , are yet held up , and kept floating by them . art. . the cause of the attraction of a less flame by a greater . art. . the cause of the inv●●ation of flame to naphtha , at distance . art. . of the ascention of water into the pores of a spunge . art. . the same ill●strated by the example of a syphon . art. . the reason of the percolation of liquors , by a cloth whose one end lieth in the liquor , and other hangs over the brim of the vessel , that contains it . art. . the reas●● of the 〈…〉 , that ar● 〈◊〉 . art. . the reason of the discent betwixt lute-strings of sheeps guts , and those of woolfs . art. . the tradition of the consuming of all feathers of foul , by those of the eagle ; exploded . art. . why some certain plants befriend , and advance the growth and fruitfulness of others , that are their neighbours . art. . why s●me plants thrive 〈…〉 of some others . art. . the ●●ason of the great frie●dship betwix● the male and fema●e palm-trees . art. . why all ●●ines grow ●ick and turbid , during the sea●on wherein th● vines fl●wer and bud. art. . that the ●●stilled waters of orange flowers , and roses , doe not take any thing of their fragrancy , during ●he 〈◊〉 of the 〈◊〉 and 〈◊〉 of those 〈◊〉 ; as 〈◊〉 vulgarly believed . art. . why this 〈…〉 only some 〈…〉 art. . 〈…〉 art. 〈…〉 . art. . 〈…〉 art. . the cause of the ●●est 〈…〉 carca●● of a mu●the●ed man 〈◊〉 the praesence and 〈◊〉 of the h●mi●ia● art. . how the basilisk doth empoyson and destroy , at distance art. . 〈…〉 . art. . 〈…〉 art. . w●y ●●●ers tarantia●al persons are affected and cured with divers t●n●s , and the musick of divers instruments . art. . th●t ●●e venome of the tarantula doth produce the same effect in the body of a man ; is it doth in that of the tarantula it self : and why . art. . that the ven●m of the tarantula is 〈◊〉 in a 〈◊〉 h●mor and such as 〈◊〉 capable of s●●nds . art . that it causeth an ●ncessent itching and 〈◊〉 ●itillation 〈◊〉 the nervous and musculous par●s of mans body , when infused into it , and ●ermenting ●n ●t . art. . the cause of the annual recidivation of the tarantism , till it be perfectly cured . art. . a conjecture , what kind of tun●● ▪ strain● and notes seem most accommodate to the cure of tarantiacal person● i● the general . art. . the reason of the incantation of serpents , by a rod of the cornus . art. . di●ression . that the 〈…〉 art. . 〈…〉 . art. . that ships are 〈…〉 . art. . that the echineis , or remora is not ominous . art. . why this place admits not of more than a general●●quest ●●quest into the faculties of po●●ons and counterpoisons . art. . poisons defined . art. . wherein the deleterious f●culty of poison doth consist . art. . counterpoisons defined . art. . wherein their salutifer●us virtue doth consist . art. . how triacle cureth the venome of vipers art. . how the body of a scorpion , bruised and laid warm upon the par● , which it hath lately wounded and envenomed ; doth cure the same . art. . that some poisons are antidotes against others by way of direct contrariety art. . why sundry particular men , and some whole nations have ●ed upon poisonous animals and plants , without harm . art. . the a ma●● vrg●●●● , and 〈◊〉 p●wder , im●ugned art. . the au●●ors retraction of his quondam de●ence of the magnetick c●re of w unds , 〈◊〉 in his p●o●egomena to he●m●nts book of that subject and title . art. . the nature and obscurity of the subject , hinted by certain metaphorical cognomina , agreeable thereunto , though in divers relations . art. . why the author insisteth not upon the ( ) several appellations , ( ) inve●●o of the loadstone , ( ) ●nvention of the pixis nautica . art. . the virtues of the loadstone , in general , two the attractive , and directive . art. 〈…〉 art. . his 〈…〉 art. . galens three grand objections against the same , briefly answered . art. . 〈…〉 art. . a par●ll●l●●●●●●wixt ●●●wixt the m●gnetique fac●l●y of the l●adstone & 〈◊〉 ; and tha● of 〈◊〉 i● animals ▪ art. . 〈…〉 art. . that every l●adstone , in respect of the circumradiation of its magnetical 〈…〉 ac●rewing . art. . the reason o● that admirable 〈◊〉 or 〈…〉 of magne●ick● ▪ and why the ●ole● of a loadstone are incapable ▪ but those of a nee●le easily capable of tran●plantation from one extreme to the contra●● . art. . an objection ▪ of the 〈◊〉 or repulsion of the north ●ole of one loa●dst●ne , or needle , by the n●rth pole of another : praeven●e● . art. . three prin●●pal magneti●●e axioms , de●uced from the same fountain art. . 〈…〉 . art. . that the magnetique vigour , or perfection both of loadstones and iron , doth consist in either their native purity and uniformity of substance , or their artificial politeness . art. that the a●ming of a magnet with polished steel , doth highly corroborate ; but a● much diminish the sphere of its attractive virtue . art. . why a smaller or weaker loadstone , doth snatch away a needle from a greater , or more potent one ; while the small or weak one is held within the sphere of the great or stronger ones activity : and not otherwis● art. . corollary . of the abduction of iron from the ear●h by a loadstone . art. . the method , and c●ntents of the section . art. . affinity of the loadstone and iron . art. . the loadst●ne conf●rms it s●lf , in all respects , to the terrest●ial globe ; as a ne●●le conforms it self to the loa●stone art. . iron obtains a verticity , not only from t●e loadstone , by affriction , or aspiration ; but also from the earth it self : and that according to the laws of p●siti●n . art. . one and the same nature , in common to the earth , loadstone and iron . art. . the earth , impraegnating iron with a polary affection , doth cause therein a locall immutation of its insensible particles . art. . the loadstone doth the same . art. . the magnetique virtue , a corporeal efflux . art. . contrar● ●bj●ctions , & their solutions . art. . a pa●alleli●me of the magnetique virtue , and the vegetative facul●● o● plants . art. . 〈…〉 of the 〈◊〉 re●●pect & name ▪ are enemies : and th●se of a contrary respect & name , friends . art. . 〈…〉 is di●●ected into two pieces , why the ●oreal part of the one half , decline ●●njunction with the boreall part of the other ; and the 〈◊〉 of one with th● aust●●ll of the other art. . the fibres of the earth extend from pole to pole ; and that may be the cause of the firme cohaesion of all its parts , conspiring to conserve its sphericall figure . art. . reason of magneticall variati●n , in divers climates and places art. . the de●rement of magneticall variation , in one and the same place , in divers years . art. . the cause thereof not yet known . art. . no m●gnet hath more ●han two legit●mate poles : and the rea●ons of illegitimate ones . art. . the conclusion ▪ apologeticall , and 〈◊〉 advert●●●●ment , that ●he attracti●● and directi●● act●●ons o● 〈…〉 notes for div a -e art. . the introduction . art. . the proper notions of generation & corruption . art. . various opinions of the ancient philosophers , touching the reason of generation : and the principall authors of pacti . art. . the two great opinions of the same philosophers concerning the manner of the commistion of the common principles , in generation ; faithfully & briefly stated . art. . that of aristotle and the stoicks , refu●ed : and chrysippus sub●erfuge , convicted of absurdities art. . ar●st●tles twof●ld ●●vation of the 〈…〉 . art. 〈…〉 art. . that the 〈◊〉 of a thing , 〈…〉 certain 〈…〉 art. . 〈…〉 . art. an illu●●r●●●on there●f , by a praegnant and o●por●un●● ins●●nce . viz. ●he generation ●f ●he , 〈…〉 . art. . that in corruption , no substance perisheth ; but only that determinate modification of substance , or matter , which specified the thing . art. . en●●rce●ent o● th●●ame th●sis , by an illustrius example . art. . an exper●ment demonstrating that the sal● of ashes was praeexistent in wood ; and no● produ●ed , but only educed by fire . art. . the 〈◊〉 sense of three g●neral ax●●ms , deduced from the precedent doct●ine of the atomists . art. . the general i●testine cau●es of corrupt●●n , chiefly tw● : ( ) the interception of ●●anity among the 〈◊〉 partic●es of b●dies . ( ) ●●e ●ential gravity and in●eparable mobility of atoms art. . the generall manners , o● ways of generation and corruption . art. . inadver●●●cy of aristotle in making five general 〈◊〉 of generati●● art. . the special manners of generation , innumerable ; and why . art. . all s●●ts o● atoms , not indi●fe●ently co●peten● to the constitution of all sorts of thing . art. . why th● nature of ●otion which d●s●rved to have been the subject of the first speculati●● ▪ was res●rved to b● the argum●nt of t●e last , in this ph●siology . art. an epicurean principle ▪ of ●un●amental concern to mo●ion . art. . 〈…〉 . art. 〈…〉 art. . emperi●●● his ●●●ections against that d●finition of epic●rus : and 〈…〉 of each art. . that t●ere is motion ; contrary ●o th● sop●●sms of parmenides , mel●ssus , zeno , d●●do●us . and the sce●ticks . art. . 〈…〉 art. the 〈◊〉 deduced from the 〈◊〉 epicurean p●●●cip●e of mo●●on , 〈◊〉 ▪ and 〈◊〉 consid●ra●le conclusions extracted from the●ce . art. . 〈◊〉 or aequanility , ●he 〈◊〉 ●haracter of a natural motion● and 〈◊〉 want of uni●ormity , of a 〈◊〉 . art. . ●he d●wnw●rd motion 〈◊〉 inanimates , derived from ●n external principle , contrary to aristotle art. art. . that the proportion , or ration of celerity to celerity , encreasing in the descent of heavy things ; is not the same as the proportion , or ration of space to space , which they pervade contrary to michael var● the mathematician ▪ art. 〈…〉 art. . the physical reason of that proportion . art. . the reason of the e●ual veloc●ty of b●dies of very d●ffe●●n● weig●ts , falling from the same altitude ; inferred from the same the●●y . art. . gravity distinguish't into simple , and adjectitious . art. . the r●●e of that superlative velocity , with which a bullet would be carried , in case it should fall from the moon , sun , or region of the ●ixed stars , to the earth : and 〈◊〉 each of those vast heights , to the 〈◊〉 of the 〈◊〉 . art. . what , and whence is that force , or virtue motive , whereby bodies projected are carried on after their dismission from the projicient . art. . the manner of the impression of that force ▪ art. . that all motion , in a free or empty space , must be vniform , and perpetual : and that the chief cause of the inequality and brevity of the motion of things projected through the atmosphere , is the magnetique attraction of the earth . art. . that , in the atmosphere , no body can be projected in a direct line ; unless perpendicularly upward , o● downward : and why . art. . that the motion of a stone pro●ected upwards obliquely , is composed of an h●●iz●●tal and perpendi●ular together . art. . demonstration of that composition . art. . that of the two different forces , impressed upon a ball , thrown upward from the hand of a man standing in a ship , that is under sayl ; the one doth not destroy the other ▪ but each attain● its proper scope . art. . t●at the space of time , in w●i●h the ●all is a●cending f●om the f 〈…〉 the top of the m●st ; is equal to that , in which it is again descending from the top to the ●oot . art. . 〈…〉 . art. . the reason and manner of the reflexion or rebounding motion of bodies , diverted from the line of their direction by others encountring them . art. . that the ●mersi●n of a weight appen●●d to a 〈…〉 the perpendicular , 〈◊〉 which it had ●●duced it self , in vibration ; 〈◊〉 a r●flexion 〈◊〉 betwixt 〈◊〉 reflexion at all , and the least reflexion assignable ; and the r●le of all other reflexion whatever . art. . ●he ●ea●●n of the ae●ualit● of the angles of in●iden●e and r●●l●xi●n . art. . two inferences from the praea●ses ▪ viz. ( ) that the oblique projection of a globe against a plane , is composed of a double parallel : and ( ) that nature suffers no diminution of her right to the shortest way , by reflexion . art. . wherein the aptitude or ine●●itude of bodies to refle●ion doth consist . the excellency of theology compar'd with natural philosophy (as both are objects of men's study) / discours'd of in a letter to a friend by t.h.r.b.e. ... ; to which are annex'd some occasional thouhts about the excellency and grounds of the mechanical hypothesis / by the same author. boyle, robert, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, mi ; oxford (uk) : - (eebo-tcp phase ). a wing b estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) the excellency of theology compar'd with natural philosophy (as both are objects of men's study) / discours'd of in a letter to a friend by t.h.r.b.e. ... ; to which are annex'd some occasional thouhts about the excellency and grounds of the mechanical hypothesis / by the same author. boyle, robert, - . [ ], , [ ], p. printed by t.n. for henry herringman ..., london : . "about the excellency and ground of the mechanical hypothesis" has special t.p. and separate paging. "t.h.r.b.e." is the honourable robert boyle, esq. errata: p.[ ] at beginning; p. [ ] before about the excellency and ground of the mechanical hypothesis. reproduction of original in the union theological seminiary library, new york. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng faith and reason. matter -- constitution. physics -- early works to . - tcp assigned for keying and markup - spi global keyed and coded from proquest page images - robyn anspach sampled and proofread - robyn anspach text and markup reviewed and edited - pfs batch review (qc) and xml conversion the excellency of theology , compar'd with natural philosophy , ( as both are objects of men's study . ) discours'd of in a letter to a friend . by t. h. r. b. e. fellow of the royal society . to which are annex'd some occasional thoughts about the excellency and grounds of the mechanical hypothesis . by the same author . felicitatem philosophi quaerunt ; theologi inveniunt ; soli religiosi possi●ent . london , printed by t. n. for henry herringman , at the anchor in the lower walk of the new exchange . . the publisher's advertisement to the reader . when i shall have told the reader , that the following discourse was written in the year , while the authour , to avoid the great plague that then rag'd in london , was reduc'd with many others to go into the countrey , and frequently to pass from place to place , unaccompanied with most of his books ; it will not , i presume , be thought strange , that in the mention of some things taken from other writers , as his memory suggested them , he did not annex in the margent the precise places that are referr'd to . and , upon the same score , it ought not to seem strange , that he has not mention'd some late discoveries and books that might have been pertinently taken notice of , and would well have accommodated some parts of his discourse ; since things that may thus seem to have been omitted , are of too recent a date to have been known to him when he writ . but if it be demanded , why then a discourse finished so long ago , did not come abroad much sooner ? i must acquaint the reader , that 't was chiefly his real concern for the welfare of the study he seems to depreciate , that kept these papers so long by him . for he resisted for several years the desires of persons that have much power with him , and suppress'd the following discourse , whilst he fear'd it might be misapply'd by some enemies to experimental philosophy , that then made a noise against it , without suffering these papers to come abroad , till the addresses and encomiums of many eminent forreign virtuosi , and their desire to be admitted into the royal society , had sufficiently manifested , how little its reputation was prejudic'd , or like to be endanger'd , by the attempts of some envious or misinform'd persons . and to this reason must be added the authors backwardness to venture abroad a discourse of an unusual nature , on which account , among others , he declin'd to have his name prefix'd to it ; though , now the book is printed , he finds cause to fear , that 't will not be long conceal'd ; since he meets with some marginal references to other tracts of his , which ( these papers having long lain by him ) he forgot to have been set down for private use , and which should not have been expos'd to publick view . errata . in the author's preface , p. . l. , . for somewhat , r. much . in the introduction , p. . l. . point thus , else ; our . in the book , p. . l. . for corpuscularium , r. corpuscularian . p , . l. . for he , r. we . p. . l. . r. theology for philosophy . p. . l. . r. yet many of . ibid. l. . r. else do but. p. . l. ult . for of . r. or . p. . l. . for indeed , r. 't will perhaps he said that . p. . l. . point thus ; predecessors , did unanimously teach . the author's preface . i am not so little acquainted with the temper of this age , and of the persons that are likeliest to be perusers of the following tract , as not to foresee it to be probable enough , that some will ask , for what reason a discourse of this nature was written at all ; and that others will be displeas'd that it has been written by me. those that would know , by what inducements my pen was engag'd on this subject , may be in great part inform'd by the epistle it self , in divers places whereof , as especially about the beginning , and at the close , the motives that invited me to put pen to paper are sufficiently express'd . and though several of those things are peculiarly apply'd , and ( if i may so speak ) appropriated to the person the letter is address'd to ; yet that undervaluation , i would disswade him from , of the study of things sacred , is not his fault alone , but is grown so rise among many ( otherwise ingenious ) persons , especially studiers of physicks , that i wish the ensuing discourse were much less seasonable than i fear it is . but i doubt , that some readers , who would not think a discourse of this nature needless or useless , may yet not be pleased at its being written by one , whom they imagine the acceptance his endeavours have met with , ought to oblige to spend his whole time in cultivating that natural philosophy , which in this letter he would perswade to quit the precedency , they think it may well challenge , before all other sorts of learning . i am not unsensible of the favourable reception that the philosophical papers i have hitherto ventured abroad , have had the happiness to receive from the curious : but i hope , they will not be displeas'd , if i represent , that i am no lecturer or professor of physicks , nor have ever engag'd my self by any promise made to the publick , to confine my self , never to write of any other subject ; nor is it reasonable , that what i did or may write , to gratifie other mens curiosity , should deprive me of mine own liberty , and confine me to one subject ; especially since there are divers persons , for whom i have a great esteem and kindness , who think they have as much right to solicit me for composures of the nature of this , that they will now have to go abroad , as the virtuosi have to exact of me physiological pieces . and though i be not ignorant , that ( in particular ) the following discourse , which seems to depreciate the study of nature , may at first sight appear somewhat improper for a person , that has purposely written to show the excellence and usefulness of it ; yet i confess , that , upon a more attentive consideration of the matter , i cannot reject , no , nor resist , their reasons , who are of a quite differing judgment . and . my condition , and my being a secular person ( as they speak ) are look'd upon as circumstances that may advantage an author that is to write upon such a subject as i have handled . i need not tell you , that as to religious books in general , it has been observ'd , that those penn'd by lay-men , and especially gentlemen , have ( caeteris paribus ) been better entertain'd , and more effectual than those of ecclesiasticks : and indeed 't is no great wonder , that exhortations to piety , and disswasions from vice , and from the lusts and vanities of the world , should be the more prevalent for being press'd by those , who have , and yet decline , the opportunities to enjoy plentifully themselves the pleasures they disswade others from . and ( to come yet closer to our present purpose ) though i will not venture to say with an excellent divine , that what ever comes out of the pulpit , does with many pass but for the foolishness of preaching ; yet it cannot well be deni'd , but that if all other circumstances be equal , he is the fittest to commend divinity , whose profession it is not ; and that it will somewhat add to the reputation of almost any study , and consequently to that of things divine , that 't is prais'd and preferr'd by those , whose condition and course of life exempting them from being of any particular calling in the common-wealth of learning , frees them from the usual temptations to partiality to this or that sort of study , which others may be engag'd to magnifie , because 't is their trade or their interest , or because 't is expected from them ; whereas these gentlemen are oblig'd to commend it , onely because they really love and value it . but there is another thing that seems to make it yet more fit , that a treatise on such a subject should be penn'd by the authour of this : for profess'd divines are suppos'd to be busied about studies , that even by their being of an higher , are confess'd to be of another , nature , than those that treat of things corporeal . and since it may be observ'd , that there is scarce any sort of learned men , that is more apt to undervalue those that are vers'd onely in other parts of knowledge , than many of our modern naturalists , ( who are conscious of the excellency of the science they cultivate , ) 't is much to be fear'd , that what would be said of the preeminences of divinity above physiology by preachers ( in whom the study of the latter is thought either but a preparatory thing , or an excursion ) would be look'd upon as the decision of an incompetent , as well as interressed , judge ; and their undervaluations of the advantages of the study of the creatures , would be ( as their depreciating the enjoyment of the creatures too often is , ) thought , to proceed but from their not having had sufficient opportunities to relish the pleasures of them . but these prejudices will not lie against a person , who has made the indagation of nature somewhat more than a parergon , and having by a not-lazie nor short enquiry manifested , how much he loves and can relish the delight it affords , has had the good fortune to make some discoveries in it , and the honour to have them publickly , and but too complementally , taken notice of by the virtuosi . and it may be not impertinent to add , that those who make natural philosophy their mistris , will probably be the less offended to find her in this tract represented , if not as an handmaid to divinity , yet as a lady of a lower rank ; because the inferiority of the study of nature is maintain'd by a person , who , even whilst he asserts it , continues ( if not a passionate ) an assiduous courter of nature : so that , as far as his example can reach , it may show , that as on the one side a man need not be acquainted with , or unfit to relish , the lessons taught us in the book of the creatures , to think them less excellent than those , that may be learned in the book of the scriptures ; so on the other side , the preference of this last book is very consistent with an high esteem and an assiduous study of the first . and if any should here object , that there are some passages , ( which i hope are but very few ) that seem a little too unfavourable to the study of natural things ; i might alledge for my excuse the great difficulty that there must be in comparing two sorts of studies , both of which a man much esteems , so to behave ones self , as to split a hair between them , and never offend either of them : but i will rather represent , that in such kind of discourses as the ensuing , it may justly be hop'd , that equitable readers will consider , not onely what is said , but on what occasion , and with what design 't is delivered . now 't is plain by the series of the following discourse , that the physeophilus , whom it most relates to , was by me look'd upon as a person , both very partial to the study of nature , and somewhat prejudic'd against that of the scripture ; so that i was not always to treat with him , as with an indifferent man , but , according to the advice , given in such cases by the wise , i was ( to use aristotle's expression ) to bend the crooked stick the contrary way , in order to the bringing it to be straight , and to depreciate the study of nature somewhat beneath its true value , to reduce a great over valuer to a just estimate of it . and to gain the more upon him , i allow'd my self now and then to make use of the contempt he had of the peripatetick and vulgar philosophy , and in some passages to speak of them more slightingly , than my usual temper permits , and than i would be forward to do on another occasion ; that , by such a complaisance for his opininions , i might have rises to argue with him from them . but to return to the motives that were alledg'd to induce me to the publication of these papers , though i have not nam'd them all , yet all of them together would scarce have prov'd effectual , if they had not been made more prevalent by the just indignation i conceived , to see even inquisitive men depreciate that kind of knowledge , which does the most elevate , as well as the most bless , mankind , and look upon the noblest and wisest employments of the understanding , as signs of weakness in it . 't is not that i expect , that whatever can be said , and much less what i have had occasion to say here , will make proselytes of those that are resolved against the being made so , and had rather deny themselves the excellentest kinds of knowledge , than allow that there can be any more excellent , than what they think themselves masters of : but i despair not , that what is here represented , may serve to fortifie in a high esteem of divine truths those that have already a just veneration for them , and preserve others from being seduc'd by injurious , though sometimes witty , insinuations , to undervalue that kind of knowledge , that is as well the most excellent in it self , as the most conducive to man's happiness . and for this reason i am the less displeas'd to see , that the following letter is swell'd to a bulk far greater than its being but a letter promises , and then i first intended . for i confess , that when the occasion hapned that made me put pen to paper , as i chanc'd to be in a very unsetled condition ( which i fear has had too much influence on what i have written , ) so i did not design the insisting near so long upon my subject as i have done ; but new things springing up ( if i may so speak ) under my pen , i was content to allow them room in my paper , because writing as well for my own satisfaction , as for that of my friend , i thought it would not be useless to lay before my own eyes , as well as his , those considerations that seem'd proper to justifie to my self as well as to him , the preference i gave divine truths ( before physiological ones ) and to confirm my self in the esteem i had for them . and though i freely confess , that the following discourse doth not consist of nothing but ratiocinations , and consequently is not altogether of an uniform contexture ; yet that will , i hope , be thought no more than was fit in a discourse , design'd not onely to convince , but to perswade : which if it prove so happy as to do , as i hope the peruser will have no cause to regret the trouble of reading it , so i shall not repent that of writing it . the introduction . sir , i hop'd you had known me better , than to doubt in good earnest , how i relish'd the discourse your learned friend entertain'd us with yester-night . and i am the more troubled at your question , because your way of inquiring , how much your friends discourse obtain'd of my approbation , gives me cause to fear , that you vouchsafe it more of yours then i could wish it . but before i can safely offer you my sense of the discourses , about which you desire to know it , i must put you in mind , that they were not all upon one subject , nor of the same nature : and i am enough his servant to acknowledge , without the least reluctancy , that he is wont to shew a great deal of wit , when he speaks like a naturalist , onely of things purely physical ; and when he is in the right , seldom wrongs a good cause by his way of managing it . but as for those passages , wherein he gave himself the liberty of disparaging the learned dr. n. onely because that doctor cultivates theological as well as physical studies and does both oftentimes read books of devotion ▪ and sometimes write them ; i am not so much a courtier , as to pretend that i liked them . 't is true , he did not deny the doctor to be a learned and a witty man , as indeed the wise providence of god has so ordered it , that to stop the bold mouthes of some , who would be easily tempted to imagine , and more easily to give out , that none are philosophers , but such as , like themselves , desire to be nothing else . our nation is happy in several men , who are as eminent for humane , as studious of divine learning ; and as great a veneration as they pay to moses and st. paul , are as well vers'd in the doctrine of aristotle , and of euclid ; nay , of epicurus and des cartes too , as those that care not to study any thing else . but though for this reason mr. n. had not the confidence to despise the doctor , and some of his resemblers , whom he took occasion to mention ; yet he too plainly disclos'd himself to be one of those , who though they will not deny , but that some , who own a value for theology , are men of parts ; yet they talk , as if such persons were so , in spight of their being religiously given ; that being , in their opinion , such a blemish , that a man must have very great abilities otherwise , to make amends for the disadvantage of valuing sacred studies , and surmount the disparagement it procures him . wherefore since this disdainful humour begins to spread much more than i could wish it did among differing sorts of men , among whom i should be glad not to find any naturalists ; and since the question you ask'd me , and the esteem you have for your friend , makes me fear you may look on it with very favourable eyes : i shall not decline the opportunity you put into my hands of giving you , together with a profession of my dislike of this practice , some of my reasons for that dislike ; and the rather , because i may do it without too much exceeding the limits of an epistle , or those which the haste , wherewith i must write this , does prescribe to me . for your friend does not oppose , but onely undervalue theology ; and professing to believe the scriptures ( which i so far credit , as to think he believes himself when he says so ) we agree upon the principles : so that i am not to dispute with him as against an atheist , that denies the authour of nature , but onely against a naturalist , that over-values the study of it . and the truths of theology are things , which i need not bring arguments for , but am allowed to draw arguments from them . but though , as i just now intimated , i design brevity ; yet for fear the fruitfulness and importance of my subject should suggest things enough to me to make some little method , requisite to keep them from appearing confused ; i shall divide the following epistle into two distinct parts . in the former of which i shall offer you the chief positive considerations , by which i would represent to you the study of divinity , as preferable to that of physicks : and in the second part i shall consider the allegations , that i foresee your friend may interpose : in favour of natural philosophy . from which distribution you will easily gather , that the motives on the one hand , and the objections on the other will challenge to themselves distinct sections in the respective parts whereto they belong . so that of the order of the particulars you will meet with , i shall not need to trouble you with any further account . the excellency of theology : or , the preeminence of the study of divinity , above that of natural philosophy . the first part . to address my self then , without any farther circumstance or preamble , to the things themselves , that i mainly intend in this discourse , i consider in the general , that as there are scarce any motives accounted fitter to engage a rational man in a study , than that the subject is noble , that 't is his duty to apply himself to it , and that his proficiency in it will bring him great advantages ; so there is not any of these three inducements , that does not concur in a very plentiful measure to recommend to us the study of theological truths . the first section . and first , the excellency and sublimity of the object we are invited to contemplate , is such , that none that does truly acknowledge a deity can deny , but that there is no speculation , whose object is comparable in point of nobleness , to the nature and attributes of god. the souls of inquisitive men are commonly so curious , to learn the nature and condition of spirits , as that the over-greedy desire to discover so much as that there are other spiritual substances besides the souls of men , has prevail'd with too many to try forbidden ways of attaining satisfaction ; and many have chosen rather to venture the putting themselves within the power of daemons , than remain ignorant whether or no there are any such beings : as i have learned by the private acknowledgments made me of such unhappy ( though not unsuccessful ) attempts , by divers learned men ( both of other professions , and that of physick , ) who themselves made them in differing places , and were persons neither timerous nor superstitious : ( but this onely upon the by. ) and certainly that man must have as wrong as mean a notion of the deity , and must but very little consider the nature and attributes of that infinitely perfect being , and as little the nature and infirmities of man , who can imagine the divine perfections to be subjects , whose investigation a man may ( inculpably ) despise , or be so much as fully sufficient for . not onely the scripture tells us , that his greatness is incomprehensible , and his wisdom is inscrutable ; that he humbles himself to look into ( or upon ) the heavens and the earth ; and , that not onely this or that man , but all the nations of the world are , in comparison of him , but like the small drop of a bucket , or the smaller dust of a ballance : but even the heathen philosopher , who wrote that eloquent book de mundo , ascrib'd to aristotle in his riper years , speaks of the power , and wisdom , and amiableness of god , in terms little less lofty , though necessarily inferiour to so infinitely sublime a subject ; which they that think they can , especially without revelation , sufficiently understand , do very little understand themselves . but perhaps your friend will object , that to the knowledge of god there needs no other then natural theology ; and i readily confess , being warranted by an apostle , that the 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , was not unknown to the heathen philosophers ; and that so much knowledge of god is attainable by the light of nature , duly employ'd , as to encourage men to exercise themselves more than most of them do in that noblest of studies , and render their being no proficients in it , injurious to themselves as well as to their maker . but notwithstanding this , as god knows himself infinitely better then purblind man knows him , so the informations he is pleased to vouchsafe us , touching his own nature and attributes , are exceedingly preferable to any account , that we can give our selves of him , without him. and methinks , the differing prospects we may have of heaven , may not ill adumbrate to us the differing discoveries that may be made of the attributes of its maker . for as , though a man may with his naked eye see heaven to be a very glorious object , enobled with radiant stars of several sorts ; yet when his eye is assisted with a good telescope , he can not onely discover a number of stars ( fix'd and wandring ) which his naked eye would never have shown him ; but those planets which he could see before , will appear to him much bigger , and more distinct : so , although bare reason well improv'd will suffice to make a man behold many glorious attributes in the deity ; yet the same reason , when assisted by revelation , may enable a man to discover far more excellencies in god , and perceive them , he contemplated before , far greater and more distinctly . and to shew how much a dim eye , illuminated by the scriptures , is able to discover of the divine perfections , and how unobvious they are to the most piercing philosophical eyes , that enjoy but the dim light of nature ; we need but consider , how much more suitable conceptions and expressions concerning god are to be met with in the writings of those fishermen and others , that penn'd the new testament , and those illiterate christians that received it , than amongst the most civiliz'd nations of the world ( such as anciently the greeks and romans , and now the chineses and east-indians ) and among the eminentest of the wise-men and philosophers themselves , ( as aristotle , homer , hesiod , epicurus , and others . ) besides that the book of scripture discloses to us much more of the attributes of god , than the book of nature ; there is another object of our study , for which we must be entirely beholding to theology : for though we may know something of the nature of god by the light of reason , yet we must owe the knowledge of his will , or positive laws , to his own revelation . and we may ghess , how curious great princes and wise men have been to inform themselves of the constitutions established by wise and eminent legislators ; partly by the frequent travels of the ancient sages and philosophers into forreign countries , to observe their laws and government , as well as bring home their learning ; and partly by those royal and sumptuous expences , at which that great and learned monarch ptolomeus philadelphus stuck not to procure an authentick copy of the law of moses , whom he considered but as an eminent legislator . but certainly that , and other laws recorded in the bible , cannot but appear more noble and worthy objects of curiosity to us christians , who know them to proceed from an omniscient deity , who being the authour of mankind , as well as of the rest of the universe , cannot but have a far perfecter knowledge of the nature of man , than any other of the law-givers , or all of them put together can be conceived to have had . but there is a farther discovery of divine matters , wherewith we are also gratified by theology : for besides what the scripture teaches us of the nature and the will of god , it contains divers historical accounts ( if i may so call them ) of his thoughts and actions . the great alexander thought himself nobly employ'd , when he read of the grecian actions in homer's verses ; and , to know the sentiments of great and wise persons , upon particular occasions , is a curiosity so laudable , and so worthy of ▪ an inquisitive soul , that the southern queen has been more prais'd than admir'd , for coming from the remoter parts of the earth , to hear the wisdom of solomon . now the scripture does in many places give our curiosity a nobler employment , and thereby a higher satisfaction , than the king of macedon , or the queen of sheba could enjoy ; for in many places it does , with great clearness and ingenuity , give us accounts of what god himself hath declar'd of his own thoughts , of divers particular persons and things , and relates , what he that knows and commands all things , was pleas'd to say & do upon particular occasions . of this sort of passages are the things recorded to have been said by god to noah , about the sinful worlds ruine , and that just man's preservation ; and to moses in the case of the daughters of zelophehad . and of this sort are the conferences , mentioned to have pass'd betwixt god and abimelech , concerning abraham's wife ; betwixt god and abraham touching the destruction of sodom ; betwixt god and solomon , about that kings happy choice ; betwixt god and jonah , about the fate of the greatest city of the world : and above all these , those two strange and matchless passages , the one in the first book of kings , touching the seducing spirit that undertook to seduce ahab's prophets ; and the other , that yet more wonderful relation of what pas'd betwixt god and satan , wherein the deity vouchsafes not onely to praise , but ( if i may so speak with reverence ) to glory in a mortal . and the being admitted to the knowledge of these transactions of another world ( if i may so call them ) wherein god has been pleased to disclose himself so very much , is an advantage afforded us by the scripture , of so noble a nature , and so unattainable by the utmost improvement we our selves can make of our own reason , that , did the scripture contain nothing else that were very considerable , yet that book would highly deserve our curiosity and gratitude . and on this occasion , i must by no means leave unobserv'd another advantage that we have from some discourses made us in the bible ; since it too highly concerns us , not to be a very great one ; and it is , that the scripture declares to us the judgment , that god is pleas'd to make of some particular men , upon the estimate of their life and deportment . for though reason alone , and the grounds of religion in general , may satisfie us in some measure , that god is good and merciful , and therefore 't is likely he may pardon the sins and frailties of men , and accept of their imperfect services ; yet , besides that we do not know , whether he will pardon , unless we have his promise of it ; besides this ( i say ) though by vertue of general revelation , such as is pretended to in divers religions , we may be assured , that god will accept , forgive , and reward those that sincerely obey him , and perform the conditions of the covenant , whether it be express , or implicite , that he vouchsafes to make with them ; yet since 't is he that is the judge of the performance of the conditions , and of the sincerity of the person ; and since he is omniscient , and a 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , and so may know more ill of us , than even we know of our selves ; a concerned conscience may rationally doubt , whether in gods estimate any particular man was so sincere as to be accepted . but when he himself is pleas'd to give elogiums ( if i may with due respect so style them ) to david , job , noah , daniel , &c. whilst they were alive , and to others after they were dead , ( and consequently having finished their course , were pass'd into an irreversible state ) we may learn with comfort , both that the performance of such an obedience as god will accept , is a thing really practicable by men ; and that even great sins and misdemeanors are not ( if seasonably repented of ) certain evidences , that a man shall never be happy in the future life . and it seems to be for such an use of consolation to frail men ( but not at all to encourage licentious ones ) that the lapses of holy persons are so frequently recorded in the scriptures . and bating those divine writings , i know no books in the world , nor all of them put together , that can give a considering christian , who has due apprehensions of the inexpressible happiness or misery of an immortal state in heaven or in hell , so great and well grounded a consolation , as may be deriv'd from three or four lines in st. john's apocalypse , where he says , that he saw in heaven a great multitude , not to be numbred , of all nations , and tribes , and people , and tongues , standing before the throne , and before the lamb , clothed in white robes , with palms ( the ensigns of victory ) in their hands ; and the praises of god and of the lamb in their mouthes . for from thence we may learn , that heaven is not reserv'd onely for prophets , and apostles , and martyrs , and such extraordinary persons , whose sanctity the church admires , but that through gods goodness , multitudes of his more imperfect servants have access thither . though the infinite perfections and prerogatives of the deity be such , that theology it self can no more than philosophy afford us another object for our studies , any thing near so sublime and excellent , as what it discloses to us of god ; yet divinity favours us with some other discoveries , namely , about angels , the universe , and our own souls , which though they must needs be inferiour to the knowledge of god himself , are , for the nobleness of their objects , or for their importance , highly preferable to any that natural philosophy has been able to afford its votaries . but before i proceed to name any more particulars , disclos'd to us by revelation , 't will be requisite , for the prevention or removal of a prejudice , to mind you , that we should not make our estimates of the worth of the things we owe to revelation , by the impressions they are wont now to make upon us christians , who learned divers of them in our catechisms , and perhaps have several times met with most of the rest in sermons , or theological books . for 't is not to be admir'd , that we should not be strongly affected at the mention of those truths , which ( how valuable soever in themselves ) were for the most part taught us when we were either children , or too youthful to discern and prize their excellency and importance . so that though afterwards they were presented to our riper understanding , yet their being by that time become familiar , and our not remembring that we ignor'd them , kept them from making any vigorous impressions on us. whereas if the same things had been ( with circumstances evincing their truth ) discover'd to some heathen philosopher , or other vertuous and inquisitive man , who valu'd important truths , and had nothing but his own reason to attain them with , he would questionless have receiv'd them with wonder and joy . which to induce us to suppose we have sundry instances , both in the records of the primitive times , and in the recent relations of the conversion of men to christianity among the people of china , japan , and other literate nations . for though bare reason cannot discover these truths , yet when revelation has once sufficiently propos'd them to her , she can readily embrace , and highly value divers of them ; which being here intimated once for all , i now advance to name some of the revelations themselves . and first , as for angels , i will not now question , whether bare reason can arrive at so much as to assure us , that there are such beings in rerum naturâ . for though reason may assure , that their existence is not impossible , and perhaps too not improbable ; yet i doubt , whether 't were to meer ratiocination , or clear experience , or any thing else but revelation , convey'd to them by imperfect tradition , that those heathen philosophers , who believ'd that there were separate spirits other than humane , ow'd that perswasion . and particularly as to good angels , i doubt , whether those antient sages had any cogent reasons , or any convincing historical proofs , or , in short , any one unquestionable evidence of any kind , to satisfie a wary person so much as of the being ( much less to give a farther account ) of those excellent spirits . whereas theology is enabled by the scripture to inform us , that not onely there are such spirits , but a vast multitude of them ; that they were made by god and christ , and are immortal , and propagate not their species ; and that these spirits have their chief residence in heaven , and enjoy the vision of god , whom they constantly praise , and punctually obey , without having sinn'd against him ; that also these good angels are very intelligent beings , and of so great power , that one of them was able in a night to destroy a vast army ; that they have degrees among themselves , are enemies to the devils , and fight against them ; that they can assume bodies shap'd like ours , and yet disappear in a trice ; that they are sometimes employ'd about humane affairs , and that not onely for the welfare of empires and kingdomes , but to protect and rescue single good men . and though they are wont to appear in a dazling splendor , and an astonishing majesty , yet they are all of them ministring spirits , employ'd for the good of the designed heirs of salvation . and they do not onely refuse mens adoration , and admonish them to pay it unto god ; but , as they are in a sense made by jesus christ , who was true man as well as god ; so they do not onely worship him , and call him simply , as his own followers were were wont to do , the lord , but stile themselves fellow servants to his disciples . and as for the other angels , though the gentiles , as well philosophers as others , were commonly so far mistaken about them , as to adore them for true gods , and yet many of them to doubt whether they were immortal ; the scripture informs us , that they are not self-originated , but created beings ; that however a great part of mankind worships them , they are wicked and impure spirits , enemies to mankind , and seducers of our first parents to their ruine ; that though they beget and promote confusion among men , yet they have some order among themselves , as having one chief , or leader ; that they are evil spirits , not by nature , but apostacy ; that their power is very limited , insomuch that a legion of them cannot invade so contemptible a thing as a herd of swine , without particular leave from god ; that not onely good angels , but good men , may , by resisting them , put them to flight , and the sincere christians that worsted them here , will be among those that shall judge them hereafter ; that their being immortal , will make their misery so too ; that they do themselves believe and tremble at those truths , they would perswade men to reject ; and that they are so far from being able to confer that happiness , which their worshippers expect from them , that themselves are wretched creatures , reserv'd in chains of darkness to the judgment of the great day ; at which they shall be doom'd to suffer everlasting torments , in the company of those wicked men that they shall have prevail'd on . we may farther consider , that as to things corporeal themselves , which the naturalist challenges as his peculiar theme , we may name particulars , and those of the most comprehensive nature , and greatest importance , whose knowledge the naturalist must owe to theology . of which truths i shall content my self to give a few instances in the world it self , or the universal aggregate of things corporeal ; that being look'd upon as the noblest and chiefest object , that the physicks afford us to contemplate . and first , those that admit the truths reveal'd by theology , do generally allow , that god is not onely the author , but creator of the world. i am not ignorant of what anaxagoras taught , of what he call'd 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 — ( and tully mentions ) in the production of the world ; and that what many other grecians afterwards taught of the worlds aeternity , is peculiarly due to aristotle , who does little less then brag , that all the philosophers that preceded him were of another mind . nor will i here examine ( which i else-where do ) whether , and how far by arguments meerly physical , the creation of the world may be evinc'd . but whether or no meer natural reason can reach so sublime a truth ; yet it seems not that it did actually , where it was not excited by revelation-discovery . for though many of the antient philosophers believ'd the world to have had a beginning , yet they all took it for granted , that matter had none ; nor does any of them , that i know of , seem to have so much as imagin'd , that any substance could be produced out of nothing . those that ascribe much more to god than aristotle , make him to have given form onely , not matter , to the world , and to have but contriv'd the pre-existent matter into this orderly systeme we call the universe . next , whereas very many of the philosophers that succeeded aristotle , suppose the world to have been aeternal ; and those that believ'd it to have been produc'd , had not the confidence to pretend to the knowing how old it was ; unless it were some extravagant ambitious people , such as those fabulous chaldaeans , whose fond account reach'd up to or years : theology teaches us , that the world is very far from being so old by or thousand years as they , and by very many ages , as divers others have presum'd ; and does , from the scripture , give us such an account of the age of the world , that it has set us certain limits , within which so long a duration may be bounded , without mistaking in our reckoning . whereas philosophy leaves us to the vastness of indeterminate duration , without any certain limits at all . the time likewise , and the order , and divers other circumstances of the manner , wherein the fabrick of the world was compleated , we owe to revelation ; bare reason being evidently unable to inform us of particulars that preceded the origine of the first man ; and though i do not think religion so much concern'd , as many do , in their opinion and practise , that would deduce particular theorems of natural philosophy from this or that expression of a book , that seems rather design'd to instruct us about spiritual than corporeal things . i see no just reason to embrace their opinion , that would so turn the two first chapters of genesis into an allegory , as to overthrow the literal and historical sense of them . and though i take the scripture to be mainly design'd to teach us nobler and better truths , than those of philosophy ; yet i am not forward to condemn those , who think the beginning of genesis contains divers particulars , in reference to the origine of things , which though not unwarily , or alone to be urg'd in physicks , may yet afford very considerable hints to an attentive and inquisitive peruser . and as for the duration of the world , which was by the old philosophers held to be interminable , and of which the stoicks opinion , that the world shall be destroyed by fire ( which they held from the jews ) was physically precarious ; theology teaches us expresly from divine revelation , that the present course of nature shall not last always , but that one day this world ( or at least this vortex of ours ) shall either be abolished by annihilation , or ( which seems far more probable ) be innovated , and , as it were , transfigur'd , and that by the intervention of that fire , which shall dissolve and destroy the present frame of nature : so that either way , the present state of things ( as well naturall as political ) shall have an end . and as theology affords us these informations about the creatures in general ; so touching the chiefest and noblest of the visible ones , men , revelation discovers very plainly divers very important things , where reason must needs be in the dark . and first , touching the body of man ; the epicureans attributed its original , as that of all things else , to the casual concourse of atoms ; and the stoicks absurdly and injuriously enough ( but much more pardonably than their follower herein , mr. hobbs ) would have men to spring up like mushrooms out of the ground ; and whereas other philosophers maintain conceits about it , too wild to be here recited ; the book of genesis assures us , that the body of man was first form'd by god in a peculiar manner , of a terrestrial matter ; and 't is there described , as having been perfected before the soul was united to it . and as theology thus teaches us , how the body of man had its first beginning ; so it likewise assures us , what shall become of the body after death , though bare natural reason will scarce be pretended to reach to so abstruse and difficult an article as that of a resurrection ; which , when propos'd by st. paul , produc'd among the athenian philosophers nothing else but wonder or laughter . not to mention , that theology teaches us divers other things about the origine and condition of mens bodies ; as , that all mankind is the off-spring of one man and one woman ; that the first woman was not made of the same matter , nor after the same manner as the first man , but was afterwards taken from his side ; that both adam and eve were not , as many epicureans and other philosophers fanci'd that the first men were , first infants ; whence they did , as we do , grow by degrees to be mature and compleat humane persons , but were made so all at once ; and , that hereafter , as all mens bodies shall rise again , so they shall all ( or at least all those of the just ) be kept from ever dying a second time . and as for the humane soul , though i willingly grant , that much may be deduc'd from the light of reason onely , touching its existence , properties , and duration ; yet divine revelation teaches it us with more clearness , and with greater authority ; as , sure , he that made our souls , and upholds them , can best know what they are , and how long he will have them last . and as the scripture expresly teaches us , that the rational soul is distinct from the body , as not being to be destroy'd by those very enemies that kill the body ; so about the origine of this immortal soul ( about which philosophers can give us but wide and precarious conjectures ) theology assures us , that the soul of man had not such an origination , as those of other animals , but was gods own immediate workmanship , and was united to the body already form'd : and yet not so united , but that upon their divorce , she will survive , and pass into a state , in which death shall have no power over her . i expect you will here object , that for the knowledge of the perpetual duration of separate souls , we need not be beholding to the scripture , since the immortality of the soul may be sufficiently prov'd by the sole light of nature , and particularly has been demonstrated by your great des cartes . but you must give me leave to tell you , that , besides that a matter of that weight and concernment cannot be too well prov'd , and consequently ought to procure a welcome for all good mediums of probation ; besides this , i say , i doubt many cartesians do , as well as others , mistake , both the difficulty under consideration , and the scope of des cartes's discourse . for i grant , that by natural philosophy alone , the immortality of the soul may be prov'd against its usual enemies , atheists and epicureans . for the ground , upon which these men think it mortal , being , that 't is not a true substance , but onely a modification of body , which consequently must perish , when the frame or structure of the body , whereto it belongs , is dissolv'd : their ground being this , i say , if we can prove by some intellectual operations of the rational soul , which matter , however modifi'd , cannot reach , that it is a substance distinct from the humane body , there is no reason , why the dissolution of the latter should infer the destruction of the former , which is a simple substance , and as real a substance as matter it self , which yet the adversaries affirm to be indestructible . but though by the mental operations of the rational soul , and perhaps by other mediums it may , against the epicureans , and other meer naturalists , who will not allow god to have any thing to do in the case , be prov'd to be immortal in the sense newly propos'd ; yet the same proofs will not evince , that absolutely it shall never cease to be ▪ if we dispute with philosophers , who admit , as the cartesians and many others do , that god is the sole creator and preserver of all things . for how are we sure but that god may have so ordain'd , that , though the soul of man , by the continuance of his ordinary and upholding concourse , may survive the body , yet , as 't is generally believ'd , not to be created till it be just to be infus'd into the body ; so it shall be annihilated when it parts with the body , god withdrawing at death that supporting influence , which alone kept it from relapsing to its first nothing . whence it may appear , that notwithstanding the physical proofs of the spirituality and separableness of the humane soul , we are yet much beholding to divine revelation for assuring us , that its duration shall be endless . and now to make good what i was intimating above , concerning the cartesians , and the scope of des cartes's demonstration , i shall appeal to no other than his own expressions to evince , that he consider'd this matter for the main as we have done , and pretended to demonstrate , that the soul is a distinct substance from the body ; but not that absolutely speaking it is immortal . cur ( answers that excellent author ) de immortalitate animae nihil scripserim , jam dixi in synopsi mearum meditationum . quod ejus ab omni corpore distinctionem satis probaverim , supra ostendi . quod vero additis , ex distinctione animae á corpore non sequi ejus immortalitatem , quia nihilominus dici potest , illam à deo talis naturae factam esse , ut ejus duratio simul cum duratione vitae corporeae finiatur , fateor á me refelli non posse . neque enim tantum mihi assumo ut quicquam de iis quae à libera dei voluntate dependent , humanae rationis vi determinare aggrediar . docet naturalis cognitio , &c. sed si de absoluta dei potestate quaeratur , an forte decreverit , ut humanae animae iisdem temporibus esse desinant , quibus corpora quae illis adjunxit ; solius dei est , respondere . and if he would not assume to demonstrate by natural reason , so much as the existence of the soul after death , unless upon a supposition ; we may well presume , that he would less take upon him to determine , what shall be the condition of that soul after it leaves the body . and that you may not doubt of this , i will give you for it his own confession , as he freely writ it in a private letter to that admirable lady , the princess elizabeth , first daughter to frederick king of bohemia , who seems to have desir'd his opinion on that important question , about which he sends her this answer , pour ce qui , &c. i. e. as to the state of the soul after this life , my knowledge of it is far inferiour to that of monsieur ( he means sir kenelm ) digby . for , setting aside that which religion teaches us of it , i confess , that by mee● natural reason we may indeed make many conjectures to our own advantage , and have fair hopes , but not any assurance : and accordingly in the next clause he gives the imprudence , of quitting what is certain for an uncertainty , as the cause why , according to natural reason , we are never to seek death . nor do i wonder he should be of that mind . for all that meer reason can demonstrate , may be reduced to these two things ; one , that the rational soul , being an incorporeal substance , there is no necessity that it should perish with the body ; so that , if god have not otherwise appointed , the soul may survive the body , and last for ever : the other , that the nature of the soul , according to des cartes , consisting in its being a substance that thinks , we may conclude , that , though it be by death separate from the body , it will nevertheless retain the power of thinking . but now , whether either of these two things , or both , be sufficient to endear the state of separation after death , to a considering man , i think may be justly question'd . for , immortality or perseverance in duration , simply consider'd , is rather a thing presuppos'd to , or a requisite of , felicity , than a part of it ; and being in it self an adiaphorous thing , assumes the nature of the state or condition to which 't is joyn'd , and does not make that state happy or miserable , but makes the possessors of it more happy or more miserable than otherwise they would be . and though some school-men , upon aery metaphysical notions , would have men think it is more eligible to be wretched , than not to be at all ; yet we may oppose to their speculative subtilties the sentiments of mankind , and the far more considerable testimony of the saviour of mankind ▪ who speaking of the disciple that betray'd him , says , that it had been good for that man if he had never been born . and eternity is generally conceived to aggravate no less the miseries of hell , than it heightens the joys of heaven . and here we may consider , first , that meer reason cannot so much as assure us absolutely , that the soul shall survive the body : for the truth of which we have not onely cartesius's confession , lately recited , but a probable argument , drawn from the nature of the thing , since , as the body and soul were brought together , not by any meer physical agents , and since their association and union whilst they continued together , was made upon conditions that depended solely upon gods free and arbitrary institution ; so , for ought reason can secure us of , one of the conditions of that association may be , that the body and soul should not survive each other . secondly , supposing that the soul be permitted to outlive the body , meer reason cannot inform us what will become of her in her separate state , whether she will be vitally united to any other kind of body or vehicle ; and if to some , of what kind that will be , and upon what terms the union will be made . for possibly she may be united to an unorganiz'd , or very imperfectly organiz'd , body , wherein she cannot exercise the same functions she did in her humane body . as we see , that even in this life the souls of natural fools are united to bodies , wherein they cannot discourse , or at least cannot philosophize . and 't is plain , that some souls are introduc'd into bodies , which , by reason of paralytical and other diseases , they are unable to move , though that does not always hinder them from being obnoxious to feel pain . so that , for ought we naturally know , a humane soul , separated from the body , may be united to such a portion of matter , that she may neither have the power to move it , nor the advantage of receiving any agreeable informations by its interventions , having upon the account of that union no other sense than that of pain . but let us now consider what will follow , if i should grant that the soul will not be made miserable , by being thus wretchedly matched . suppose we then , that she be left free to enjoy what belongs to her own nature : that being onely the power of always thinking , it may well be doubted , whether th'exercise of that power wil suffice to make her happy . you will perchance easily believe , that i love as well as another to entertain my self with my own thoughts , and to enjoy them undisturbed by visits , and other avocations ; i would , onely accompanied by a servant and a book , go to dine at an inn upon a road , to enjoy my thoughts the more freely for that day . but yet , i think , the most contemplative men would , at least in time , grow weary of thinking , if they received no supply of objects from without , by reading , seeing , or conversing ; and if they also wanted the opportunity of executing their thoughts , by moving the members of their bodies , or of imparting them , either by discoursing , or writing of books , or by making of experiments . on this occasion i remember , that i knew a gentleman , who was , in spain , for a state-crime , which yet he thought an heroick action , kept close prisoner for a year in a place , where though he had allowed him a diet not unfit for a person of note , as he was ; yet he was not permitted the benefit of any light , either of the day or candles , and was not accosted by any humane creature , save at certain times by the jaylor , that brought him meat and drink , but was strictly forbidden to converse with him . now though this gentleman by his discourse appear'd to be a man of a lively humour , yet being ask'd by me , how he could do to pass the time in that sad solitude , he confessed to me , that , though he had the liberty of walking too and fro in his prison , and though by often recalling into his mind all the adventures and other passages of his former life , and by several ways combining and diversifying his thoughts , he endeavoured to give his mind as much variety of employment as he was able ; yet that would not serve his turn , but he was often reduc'd , by drinking large draughts of wine , and then casting himself upon his bed , to endeavour to drown that melancholly , which the want of new objects cast him into . and i can easily admit , he found a great deal of difference between the sense he had of thinking when he was at liberty , and that which he had when he was confin'd to that employment , whose delightfulness , like fire , cannot last long , when it is , as his was , denied both fuel and vent . and , in a word , though i most readily grant , that thinking interwoven with conversation and action , may be a very pleasant way of passing ones time , yet man being by nature a sociable creature , i fear , that alone would be a dry and wearisome imployment to spend eternity in . before i proceed to the next section , i must not omit to take notice , that though the brevity i propos'd to my self , keeps me from discoursing of any theological subjects , save what i have touch'd upon about the divine attributes , and the things i have mention'd about the universe in general , and the humane soul ; yet there are divers other things , knowable by the help of revelation , and not without it , that are of so noble and sublime a nature , that the greatest wits may find their best abilities both fully exercis'd , and highly gratifi'd by making enquiries into them . i shall not name for proof of this the adorable mystery of the trinity , wherein 't is acknowledg'd , that the most soaring speculators are wont to be pos'd , or to loose themselves : but i shall rather mention the redemption of mankind , and the decrees of god concerning men. for though these seem to be less out of the ken of our natural faculties ; yet 't is into some things that belong to the former of them , that the scripture tells us , the angels desire to pry ; and 't was the consideration of the latter of them , that made one that had been caught up into the mansion of the angels , amazedly cry out , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , &c. not are these the onely things that the scripture it self terms mysteries , though , for brevities sake , instead of specifying any of them , i shall content my self to represent to you in general ; that , since gods wisdom is boundless , it may , sure , have more ways than one to display it self . and though the material world be full of the productions of his wisdom ; yet that hinders not but that the scripture may be enobled with many excellent impresses , and , as it were , signatures of the same attribute . for , as i was beginning to say , it cannot but be highly injurious to the deity , in whom all other true perfections , as well as omniscience , are both united and transcendent , to think , that he can contrive no ways to disclose his perfections , besides the ordering of matter and motion , and cannot otherwise deserve to be the object of mens studies , and their admiration , than in the capacity of a creator . and i think , i might safely add , that besides these grand and mysterious points i came from mentioning , there are many other noble and important things , wherein unassisted reason leaves us in the dark ; which though not so clearly reveal'd in the scripture , are yet in an inviting measure discover'd there , and consequently deserve the indagation of a curious and philosophical soul. shall we not think it worth enquiring , whether the satisfaction of christ was necessary to appease the justice of god , and purchase redemption for mankind ? or whether god , as absolute and supreme governour of the world , might have freely remitted the penalties of sin ? shall we not think it worth the inquiring , upon what account , and upon what terms , the justification of men ●●wards god is transacted , especially considering how much it imports us to know , and how perplexedly a doctrine , not in it self abstruse , is wont to be delivered ? shall not we inquire , whether or no the souls of men , before they were united to their bodies , pre-existed in a happier state , as many of the ancient and modern jews and platonists , and ( besides origen ) some learned men of our times do believe ▪ and shall not we be curious to know , whether , when the soul leaves the body , it do immediately pass to heaven or hell ( as 't is commonly believed , ) or for want of organs be laid , as it were , asleep in an insensible and unactive state , till it recover the body at the resurrection ? ( as many socinians and others maintain : ) or whether it be conveyed into secret recesses , where , though it be in a good or bad condition , according to what it did in the body , 't is yet repriev'd from the flames of hell , and restrain'd from the beatifick vision till the day of judgment ? ( which seems to have been the opinion of many , if not most of the primitive fathers and christians . ) shall not we be curious to know , whether at that great decretory day , this vast fabrick of the world , which all confess must have its frame quite shatter'd , shall be suffer'd to relapse into its first nothing , ( as several divines assert ; ) or shall be , after its dissolution , renew'd to a better state , and , as it were , transfigur'd ? and shall not we inquire , whether or no in that future state of things , which shall never have an end , we shall know one another ? ( as adam , when he awak'd out of his profound sleep , knew eve whom he never saw before ; ) and whether those personal friendships and affections , we had for one another here , and the pathetick consideration of the relations ( as of father and son , husband and wife , chaste mistris and virtuous lover , prince and subject , ) on which many of them were grounded , shall continue ? or whether all those things , as antiquated and slight , shall be obliterated , and , as it were , swallowed up ? ( as the former relation of a cousin a great way off , is scarce at all consider'd , when the persons come so to change their state , as to be united by the strict bonds of marriage . ) but 't were tedious to propose all the other points , whereof the divine takes cognizance , that highly merit an inquisitive mans curiosity ; and about which , all the writings of the old greek and other heathen philosophers put together , will give us far less information , than the single volume of canonical scripture . i foresee indeed , that it may nevertheless be objected , that in some of these inquiries , revelation incumbers reason , by delivering things , which reason is obliged to make its hypothesis consistent with . but , besides that this cannot be so much as pretended of all ; if you consider how much unassisted reason leaves us in the dark about these matters , wherein she has not been able to frame so much as probable determinations , especially in comparison of those probabilities that reason can deduce from what it finds one way or other delivered in the scripture : if you consider this , i say , you will , i presume , allow me to say , that the revealed truths , which reason is obliged to comply with , if they be burdens to it , are but such burdens as feathers are to a hawk , which instead of hindring his flight by their weight , enable him to soar toward heaven , and take a larger prospect of things , than , if he had not feathers , he could possibly do . and on this occasion , sir , the greater reverence i owe to the scripture it self , than to its expositors , prevails upon me to tell you freely , that you will not do right , either to theology , or ( the greatest repository of its truths ) the bible ; if you imagine that there are no considerable additions to be made to the theological discoveries we have already , nor no clearer expositions of many texts of scripture , or better reflections on that matchless book , than are to be met with in the generality of commentators , or of preachers , without excepting the antient fathers themselves . for , there being in my opinion two things requisite , to qualifie a commentator to do right to his theme , a competency of critical knowledge , and a concern for the honour and interest of christianity in general , assisted by a good judgment to discern and select those things that may most conduce to it ; i doubt , there are not many expositors , as they are call'd , of the scripture , that are not deficient in the former or the latter of these particulars , and i wish there be not too many that are defective in both . that the knowledge of at least greek and hebrew is requisite to him , that takes upon him to expound writings penn'd originally in those languages , if the nature of the thing did not manifest it , you might easily be perswaded to believe , by considering with what gross mistakes the ignorance of languages has oftentimes blemish'd not onely the interpretations of the school-men and others , but even those of the venerable fathers of the church . for though generally they were worthy men , and highly to be regarded , as the grand witnesses of the doctrines and government of the antient churches ; most of them very pious , many of them very eloquent , and some of them ( especially the two criticks , origen and jerom ) very learned ; yet so few of the greek fathers were skill'd in hebrew , and so few of the latin fathers either in hebrew or greek , that many of their homilies , and even comments , leave hard texts as obscure as they found them ; and , sometimes misled by bad translations , they give them senses exceeding wide of the true : so that many times in their writings they appear to be far better divines then commentators , and in an excellent discourse upon a text , you shall find but a very poor exposition of it . many of their eloquent and devout sermons being much better encomiasts of the divine mysteries they treat of , than unvailers . and though some modern translations deserve the praise of being very useful , and less unaccurate than those which the latine fathers us'd ; yet when i read the scriptures ( especially some books of the old testament ) in their originals , i confess i cannot but sometimes wonder , what came into the mind of some , even of our modern translators , that they should so much mistake , and sometimes injure certain texts as they do ; and i am prone to think , that there is scarce a chapter in the bible ( especially that part of it which is written in hebrew ) that may not be better translated , and consequently more to the credit of the book it self . this credit it misses of , not onely by mens want of sufficient skill in critical learning , but ( to come to the second member of our late division ) for want of their having judgment enough to observe , and concern enough to propose those things in the scripture , and in theology , that tend to the reputation of either . for i fear there are too many , both commentators and other divines , that ( though otherwise perhaps pious men ) having espous'd a church or party , and an aversion from all dissenters , are solicitous when they peruse the scripture , to take notice chiefly , if not onely ( i mean in points speculative ) of those things , that may either suggest arguments against their adversaries , or answers to their objections . but i meet with much fewer than i could wish , who make it their business to search the scriptures for those things ( such as unheeded prophecies , over-look'd mysteries , and strange harmonies ) which being clearly and judiciously proposed , may make that book appear worthy of the high extraction it challenges ( and consequently of the veneration of considering men ) and who are sollicitous to discern and make out , in the way of governing and of saving men , reveal'd by god , so excellent an oeconomy , and such deep contrivances , and wise dispensations , as may bring credit to religion , not so much as 't is roman , or protestant , or socinian , but as 't is christian . but ( as i intimated before ) these good affections for the repute of religion in general , are to be assisted by a deep judgment . for men that want either that , or a good stock of critical learning , may easily over-see the best observations ( which usually are not obvious ) or propose as mysteries , things that are either not grounded , or not weighty enough ; and so ( notwithstanding their good meaning ) may bring a disparagement upon what they desire to recommend . and i am willing to grant , that 't is rather for want of good skill and good judgment , than good will , that there are so few that have been careful to do right to the reputation of the scripture , as well as to its sense . and indeed when i consider , how much more to the advantage of those sacred writings , and of christian theology in general , divers texts have been explain'd and discours'd of by the excellent grotius , by episcopius , masius , mr. mede , and sir francis bacon , and some other late great wits ( to name now no living ones ) in their several kinds ; than the same places have been handled by vulgar expositors , and other divines : and when i remember too , that none of these newly named worthies was at once a great philosopher , and a great critick ; ( the three first being not so well vers'd in philosophical learning , and the last being unacquainted with the eastern tongues : ) i cannot but hope , that when it shall please god to stir up persons of a philosophical genius , well furnish'd with critical learning , and the principles of true philosophy , and shall give them a hearty concern for the advancement of his truths ; these men , by exercising upon theological matters , that inquisitiveness and sagacity that has made in our age such a happy progress in philosophical ones , will make explications and discoveries , that will justifie more than i have said in praise of the study of our religion and the divine books that contain the articles of it . for these want not excellencies , but onely skilful unvailers . and if i do not tell you , that you should no more measure the wisdom of god couch'd in the bible , by the glosses or systems of common expositors and preachers , than estimate the wisdome he has express'd in the contrivance of the world by magirus's or eustachius's physicks ; yet i shall not scruple to say , that you should as little think , that there are no more mysteries in the books of scripture , besides those that the school-divines and vulgar commentators have taken notice of , and unfolded ; as that there are no other mysteries in the book of nature , than those which the same school-men ( who have taken upon them to interpret aristotle and nature too ) have observ'd and explain'd . all the fine things , that poets , orators , and even lovers have hyperbolically said in praise of the beauty of eyes , will nothing near so much recommend them to a philosophers esteem , as the sight of one eye skilfully dissected , or the unadorn'd account given of its structure , and the admirable uses of its several parts , in scheiner's oculus , and des-cartes's excellent dioptricks . and though i do not think my self bound to acquiesce in , and admire every thing that is propos'd as mysterious and rare by many interpreters and preachers ; yet i think , i may safely compare several things in the books we call the scripture , to several others in that of nature , in ( at least ) one regard . for , though i do not believe all the wonders , that pliny , aelian , porta , and other writers of that stamp , relate of the generation of animals ; yet by perusing such faithful and accurate accounts , as sometimes galen , de usu partium , sometimes vesalius , sometimes our harvey ( de ovo ) and our later anatomists , and sometimes other true naturalists , give of the generation of animals , and of the admirable structure of their bodies , especially those of men , and such other parts of zoology , as pliny , and the other writers i nam'd with him , could make nothing considerable of ; by perusing these ( i say ) i receive more pleasure and satisfaction , and am induc'd more to admire the works of nature , than by all their romantic and superficial narratives . and thus ( to apply this to our present subject ) a close and critical account of the more vail'd and pregnant parts of scripture , and theological matters , with such reflections on them , as their nature and collation would suggest to a philosophical , as well as critical , speculator , would far better please a rational considerer , and give him a higher , as well as a better grounded , veneration for the things explain'd , than a great many of those sleighter or ill-founded remarks , wherewith the expositions and discourses of superficial writers , though never so florid or witty , gain the applause of the less discerning sort of men . and here , on this occasion , i shall venture to add , that i despair not , but that a further use may be made of the scripture , than either our divines or philosophers seem to have thought on . some few theologues indeed have got the name of supralapsarians , for venturing to look back beyond the fall of adam for god's decrees of election and reprobation . but , besides that their boldness has been dislik'd by the generality of divines , as well as other christians , the object of their speculation is much too narrow to be any thing near and adequate to such an hypothesis as i mean. for me-thinks , that the encyclopedia's and pansophia's , that even men of an elevated genius have aimed at , are not diffus'd enough to comprehend all that the reason of a man , improv'd by philosophy , and elevated by the revelations already extant in the scripture , may , by the help of free ratiocination , and the hints contain'd in those pregnant . writings ( with those assistances of god's spirit , which he is still ready to vouchsafe to them that duly seek them , ) attain unto in this life . the gospel comprises indeed , and unfolds the whole mystery of man's redemption , as far forth as 't is necessary to be known for our salvation : and the corpusculariùm or mechanical philosophy , strives to deduce all the phoenomena of nature from adiaphorous matter , and local motion . but neither the fundamental doctrine of christianity , nor that of the powers and effects of matter and motion , seems to be more than an epicycle ( if i may so call it ) of the great and universal system of god's contrivances , and makes but a part of the more general theory of things , knowable by the light of nature , improv'd by the information of the scriptures : so that both these doctrines , though very general , in respect of the subordinate parts of theology and philosophy , seem to be but members of the universal hypothesis , whose objects , i conceive , to be the nature , counsels , and works of god , as far as they are discoverable by us ( for i say not to us ) in this life . for those , to whom god has vouchsafed the priviledge of mature reason , seem not to enlarge their thoughts enough , if they think , that the omniscient and almighty god has bounded the operations of his power , and wisdom , and goodness , to the exercise that may be given them for some ages , by the production and government of matter and motion , and of the inhabitants of the terrestrial globe , which we know to be but a physical point in comparison of that portion of universal matter , which we have already discover'd . for i account , that there are four grand communities of creatures , whereof things meerly corporeal make but one ; the other three , differing from these , are distinct also from one another . of the first sort are the race of mankind , where intellectual beings are vitally associated with gross and organical bodies . the second are daemons , or evil angels ; and the third , good angels ; ( whether in each of those two kinds of spirits , the rational beings be perfectly free from all union with matter , though never so fine and subtile ; or whether they be united to vehicles , not gross , but spirituous , and ordinarily invisible to us. ) nor may we think , because angels and devils are two names quickly utter'd , and those spirits are seldome or never seen by us , there are therefore but few of them , and the speculation of them is not considerable . for , as their excellency is great , ( as we shall by and by shew ) so for their number , they are represented in scripture as an heavenly host , standing on the right and left hand of the throne of god. and of the good angels , our saviour speaks of having more than twelve legions of them at his command . nay , the prophet daniel saith , that to the antient of days , no less than millions ministred unto him , and hundreds of millions stood before him . and of the evil angels the gospel informs us , that enough to call them a legion ( which you know is usually reckon'd , at a moderate rate ▪ to consist of betwixt six and seven thousand ) possess'd one single man. for my part , when i consider , that matter , how vastly extended , and how curiously shap'd soever , is but a brute thing , that is onely capable of local motion and its effects and consequents on other bodies , or the brain of man , without being capable of any true , or at least any intellectual , perception , or true love or hatred ; and when i consider the rational soul as an immaterial and immortal being , that bears the image of its divine maker , being indow'd with a capacious intellect , and a will that no creature can force : i am by these considerations dispos'd to think the soul of man a nobler and more valuable being , than the whole corporeal world ; which though i readily acknowledge it to be admirably contriv'd , and worthy of the almighty and omniscient author , yet it consists but of an aggregate of portions of brute matter , variously shap'd and connected by local motion ( as dow , and roles , and loves , and cakes , and vermicelli , wafers , and pie-crust , are all of them diversified meal ; ) but without any knowledge either of their own nature , or of that of their author , or of that of their fellow-creatures . and as the rational soul is somewhat more noble and wonderful , than any thing meerly corporeal , how vast soever it can be , and is of a more excellent nature , than the curiousest piece of mechanism in the world , the humane body ; so to enquire what shall become of it , and what fates it is like to undergo hereafter , does better deserve a man's curiosity , than to know what shall befall the corporeal universe , and might justly have been to nebuchadnezzar a more desirable part of knowledge , than that he was so troubled for want of , when it was adumbrated to him in the mysterious dream , that contain'd the characters and fates of the four great monarchies of the world. and as man is intrusted with a will of his own , whereas all material things move onely as they are mov'd , and have no self-determining power , on whose account they can resist the will of god ; and as also of angels , at least some orders of them , are of a higher quality ( if i may so speak ) than humane souls ; so 't is very probable , that in the government of angels , whether good or bad , that are intellectual voluntary agents , there is requir'd and employ'd far greater displays of gods wisdom , power , and goodness , than in the guidance of adiaphorous matter ; and the method of god's conduct in the government of these , is a far nobler object for men's contemplation , than the laws , according to which the parts of matter hit against , and justle , one another , and the effects or results of such motions . and accordingly we find in scripture , that , whereas about the production of the material world , and the setting of the frame of nature , god employ'd onely a few commanding words , which speedily had their full effects ; to govern the race of mankind , even in order to their own happiness , he employ'd not onely laws and commands , but revelations , miracles , promises , threats , exhortations , mercies , judgments , and divers other methods and means ; and yet oftentimes , when he might well say , as he did once by his prophet , what could i have done more to my vineyard that i have not done it ? he had just cause to expostulate as he did in the same place , wherefore , when i looked that it should bring forth grapes , brought it forth wild grapes ? and to complain of men , as by that very prophet he did even of israel , i have spread out my hands all the day to a rebellious people . but not to wander too far in this digression ; what we have said of men , may render it probable , that the grand attributes of god are more signally exercis'd , and made more conspicuous in the making and governing of each of the three intellectual communities , than in the framing and upholding the community of meer bodily things . and since all immaterial substances are for that reason naturally immortal , and the universal matter is believ'd so too , possibly those revolutions , that will happen after the day of judgment , wherein though probably not the matter , yet that state and constitution of it , on whose account it is this world , will be destroyed , and make way for quite new frames and sets of things corporeal , and the beings that compose each of these intellectual communities , will , in those numberless ages they shall last , travel through i know not how many successive changes and adventures ; perhaps , i say , these things will no less display , and bring glory , to the divine attributes , than the contrivance of the world , and the oeconomy of man's salvation , though these be ( and that worthily ) the objects of the naturalists and the divines contemplation . and there are some passages in the prophetical part of the scripture , and especially in the book of the apocalypse , which , as they seem to intimate , that as god will perform great and noble things , which mechanical philosophy never reach'd to , and which the generality of divines seem not to have thought of ; so divers of those great things may be , in some measure , discover'd by an attentive searcher into the scriptures , and that so much to the advantage of the devout indagator , that st. john , near the beginning of his revelations , pronounces them happy , that read the matters contain'd in this prophecy , and * observe the things written therein . which implies , that by heedful comparing together the indications couched in those prophetick writings , with events and occurrences in the affairs of the world , and the church , we may discover much of the admirable oeconomy of providence in the governing of both : and i am prone to think , the early discoveries of such great and important things , to be in gods account no mean vouchsafements , not onely because of the title of happy is here given to him that attains them , but because the two persons , to whom the great discoveries of this kind were made , i mean , the prophet daniel and st. john , the first is by the angel said to be , on that account , a person highly favour'd ; and the other is in the gospel represented as our saviour's beloved disciple . and you will the more easily think the foreknowledge of the divine dispensations gatherable from scripture to be highly valuable , if you consider , that , according to st. paul , those very angels that are call'd principalities and powers in heavenly places , learnt by the church some abstruse points of the manifold wisdom of god. but i must no longer indulge speculations , that would carry my curiosity beyond the bounds of time it self , and therefore beyond those that ought to be plac'd to this occasional excursion . and yet , as on the one side , i shall not allow my self the presumption of framing conjectures about those remote dispensations , which will not , most of them , have a beginning before this world shall have an end ; so on the other side i would not discourage you , or any pious inquirer , from endeavouring to advance in the knowledge of those attributes of god , that may successfully be studied , without prying into the secrets of the future . and here , sir , let me freely confess to you , that i am apt to think , that , if men were not wanting to gods glory , and their own satisfaction , there would be far more discoveries made , than are yet attain'd to , of the divine attributes . when we consider the most simple or uncompounded essence of god , we may easily be perswaded , that what belongs to any of his attributes ( some of which thinking men generally admire ) must be an object of enquiry exceeding noble , and worthy of our knowledge . and yet the abstruseness of this knowledge is not in all particulars so invincible , but that i strongly hope , a philosophical eye , illustrated by the revelations extant in the scripture , may pierce a great deal farther than has yet been done , into those mysterious subjects , which are too often ( perhaps out of a mistaken reverence ) so poorly handled by divines and schoolmen , that not onely what they have taught , is not worthy of god ( for that 's a necessary , and therefore excusable , deficiency ) but too frequently it is not worthy of men , i mean , of rational creatures , that take upon them to treat of such high points , and instruct others about them . and i question not but your friend will the less scruple at this , if he call to mind those new and handsome notions about some of the attributes of god , that his master cartesius , though but moderately vers'd in the scriptures , has presented us with . nor do i doubt but that a much greater progress might be made in the discovery of subjects , where , though we can never know all , we may still know farther , if speculative genius's would propose to themselves particular doubts and enquiries about particular attributes , and frame and examine hypotheses , establish theorems , draw corollaries ; and ( in short ) apply to this study the same sagacity , affiduity , and attention of mind , which they often imploy about inquiries of a very much inferiour nature ; insomuch as des-cartes ( how profound a geometrician soever he were ) confesses in one of his epistles , that he employ'd no less then six weeks to find the solution of a problem or question of pappus . and pythagoras was so addicted to , and concern'd for geometrical speculations , that when he had found that famous proposition , which makes the th . in euclid's i. book , he is recorded to have offer'd a hecatomb , to express his joy and gratitude for the discovery : which yet was but of one property of one sort of right-lin'd triangles . and certainly if christian philosophers did rightly estimate , how noble and fertile subjects the divine attributes are , they would find in them wherewithall to exercise their best parts , as well as to recompence the imployment of them . but because what i would disswade , does not perhaps proceed onely from laziness , but from a mistake ; as if there were little to be known of so incomprehensible an object as god , save that in general all his attributes are like himself , infinite , and consequently not to be fully known by humane understandings , because they are finite ; i shall add , that though it be true , that by reason of god's infinity , we cannot comprehend him , that is , have a full and adequate knowledge of him ; yet we may not onely know very many things concerning him , but , which is more , may make an endless progress in that knowledge . as , no doubt , pythagoras ( newly mention'd ) knew very well what a triangle was , and was acquainted with divers of its properties and affections before he discover'd that famous one. and though since him , euclid , archimedes , and other geometricians have demonstrated , i know not how many other affections of the same figure , yet they have not to this day exhausted the subject : and possibly , i , ( who pretend not to be a mathematician ) may now and then in managing certain aequations i had occasion for , have lighted upon some theorems about triangles , that occurr'd not to any of them . the divine attributes are such fruitful themes , and so worthy of our admiration , that the whole fabrick of the universe , and all the phenomena exhibited in it , are but imperfect expressions of gods wisdom , and some few of his other attributes . and i do not much marvel , that the angels themselves are represented in scripture as imploy'd in adoring god , and admiring his perfections . for even they being but finite , can frame but inadequate conceptions of him ; and consequently must endeavour by many of them to make amends for the incompleatness of every one of them ; which yet they can never but imperfectly do . and yet gods infinity can but very improperly be made a discouragement of our enquiries into his nature and attributes . for ( not now to examine whether infinity , though express'd by a negative word , be not a positive thing in god ) we may , notwithstanding his infinity , discover as much of him as our nature is capable of knowing : and what harm is it to him that is drinking in a river , that he cannot drink up all the water , if he have liberty fully to quench his thirst , and take in as much liquor as his stomack can contain . infinity therefore should not hinder us from a generous ambition to learn as much as we can of an object , whose being infinite does but make our knowledge of it the more noble and desirable , which indeed it is in such a degree , that we need not wonder that the angels are represented as never weary of their employment of contemplating and praising god. for , as i lately intimated , that they can have but inadequate idea's of those boundless perfections , and by no number of those idea's can arrive to make amends for the incompleatness of them ; so it need not seem strange that in fresh discoveries of new parts ( if i may so call them ) of the same object , it being such a one , they should find nobler and happier entertainments than any where else variety could afford them . the second section . having thus taken notice of some particulars of those many which may be employ'd to shew , how noble the objects are , that theology proposes to be contemplated ; i now proceed to some considerations that may make us sensible how great an obligation there lies on us , to addict our selves to the study of them . yet of the particulars whereon this obligation may be grounded , i shall now name but two , they being indeed comprehensive ones , obedience , and gratitude . and first let me represent , that it needs not , i suppose , be solicitously proved , that 't is the will and command of god , that men should learn those truths that he has been pleased to teach , whether concerning his nature or attributes , or the way wherein he will be served and worshipped by man. for if we had not injunctions of scripture to that purpose , yet your friend is too rational a man to believe , that god would so solemnly cause his truths to be published to mankind , both by preaching and writing , without intention to oblige , those ( at least ) that have the capacity and opportunity to enquire into some of them ; and if it appear to be his will , that a person so qualified , should search after the most important truths that he hath reveal'd , it cannot but be their duty to do so . for though the nature of the thing it self did not lay any obligation on us , yet the authority of him that commands it , would : since being the supreme and absolute lord of all his creatures , he has as well a full right to make what laws he thinks fit , and enjoyn what service he thinks fit , as a power to punish those that either violate the one , or deny the other ; and accordingly 't is very observable , that before adam fell , and had forfeited his happy state by his own transgression , he not onely had a law impos'd upon him , but such a law , as , being about a matter it self indifferent ( for so it was to eat or not to eat of the tree of life as well as of any other , ) derived its whole power of obliging from the meer will and pleasure of the law-giver . whence we may learn , that man is subject to the laws of god , not as he is obnoxious to him , but as he is a rational creature , and that the thing that is not a duty in its own nature , may become an indispensible one barely by its being commanded . and indeed , if our first parent in the state of innocency and happiness , wherein he tasted of gods bounty , without , as yet , standing in need of his mercy , was most strictly obliged out of meer obedience to conform to a law , the matter of which was indifferent in it self ; sure we , in our laps'd condition , must be under a high obligation to obey the declared will of god , whereby we are enjoyned to study his truths , and perform that which has so much of intrinsick goodness in it , that it would be a duty , though it were not commanded ; and has such recompences proposed to it , that it is not more a duty , then it will be an advantage . but it is not onely obedience and interest that should engage us to the study of divine things , but gratitude , and that exacted by so many important motives , that he who said , ingratum si dixeris , omnia dixeris , could not think ingratitude so much worse than ordinary vices , as a contempt of the duty i am pressing , would be worse than an ordinary ingratitude . it were not difficult on this occasion to manifest , that we are extremely great debtors unto god , both as he is the authour and the preserver of our very beings ; and as he ( immediately or mediately ) fills up the measure of those continual benefits with all the prerogatives and other favours we do receive from him as men ; and the higher blessings , which ( if we are not wanting to our selves ) we may receive from him as christians . but to shew , in how many particulars , and to how high a degree , god is our benefactor , were to lanch out into too immense a subject ; which 't were the less proper for me to do , because i have in other papers discours'd of those matters already . i will therefore single out a motive of gratitude , which will be peculiarly pertinent to our present purpose . for whereas your friend does so highly value himself upon the study of natural philosophy , and despises not onely divines , but states-men , and even the learned'st men in other parts of philosophy and knowledge , because they are not vers'd in physicks ; he ows to god that very skill , among many other vouchsafements . for it is god who made man unlike the horse and the mule , who have no understanding , and endow'd him with that noble power of reason , by the exercise of which he attains to whatever knowledge he has of natural things above the beasts that perish . for , that may justly be applied to our other acquisitions , which moses , by gods appointment , told the israelites concerning the acquists of riches ; where he bids the people beware , that when their herds , and their flocks , and other treasures were multipli'd , their heart be not lifted up , and prompt them to say , my power , and the might of my hand hath gotten me this wealth . but , ( subjoyns that excellent person , as well as matchless law-giver ) thou shalt remember the lord thy god , for it is he that giveth thee power to get wealth . but to make men rational creatures , is not all god has done towards the making them philosophers . for , to the knowledge of particular things , objects are as well requisite as faculties ; and if we admit the probable opinion of divines , who teach us , that the angels were created before the material world , as being meant by those sons of god , and morning stars , that with glad songs and acclamations celebrated the foundations of the earth ; we must allow , that there were many creatures endowed with at least as much reason as your friend , who yet were unacquainted with the mysteries of nature , since she her self had not yet receiv'd a being . wherefore god having as well made the world , as given man the faculties whereby he is enabled to contemplate it ; naturalists are as much obliged to god for their knowledge , as we are for our intelligence to those that write us secrets in cyphers , and teach us the skill of decyphering things so written ; or to those who write what would fill a page in the compass of a single peny , and present us to boot a microscope to enable us to read it . and as the naturalist hath peculiar inducements to gratitude for the endowment of knowledge ; so ingenuity lays this peculiar obligation on him to express his gratitude in the way i have been recommending , that 't is one of the acceptablest ways it can be express'd in ; especially since by this way , philosophers may not onely exercise their own gratitude towards god , but procure him that of others . how pleasing mens hearty praises are to god , may appear among other things , by what is said and done by that royal poet , whom god was pleased to declare a man after his own heart ; for he introduces god pronouncing , whoso offereth praise , glorifieth me ; where the word our interpreters render offereth , in the hebrew signifies to sacrifice ; with which agrees , that else-where those that pay god their praises , are said to sacrifice to him the calves of their lips . and that excellent person , to whom god vouchsafed so particular a testimony , was so assiduous in this exercise , that the book which we , following the greek , call psalms , is , in the original , from the things it most abounds with , called sepher tehillim , i. e. the book of praises . and to let you see , that many of his praises were such , as the naturalist may best give , he exclaims in one place , how manifold are thy works , o lord ? how wisely hast thou made them , ( as junius and tremellius render it , and the hebrew will bear ) and else-where , the heavens declare the glory of god , and the firmament sheweth his handy-work , &c. again , in another place , i will praise thee , because i am fearfully and wonderfully made . marvellous are thy works , and that my soul knoweth right well . and not content with many of the like expressions , he does several times in a devout transport , and poetical strain , invite the heavens , and the stars , and the earth , and the seas , and all the other inanimate creatures , to joyn with him in the celebration of their common maker . which though it seem to be meerly a poetical scheme , yet in some sort it might become a naturalist , who by making out the power , wisdom , and goodness of the creator , and by reflecting thence on those particulars wherein those attributes shine , may , by such a devout consideration of the creatures , make them , in a sense , joyn with him in glorifying their author . in any other case , i dare say , your friend is not so ill natur'd , but that he would think it an unkind piece of ingratitude , if some great and excellent prince , having freely and transcendently obliged him , he should not concern himself to know what manner of man his benefactor is ; and should not be solicitous to inform himself of those particulars , relating to the person and affairs of that obliging monarch , which were not onely in themselves worthy of any mans curiosity , but about which the prince had solemnly declar'd he was very desirous to have men inquisitive . and sure 't is very disingenious , to undervalue or neglect the knowledge of god himself for a knowledge which we cannot attain without him , and by which he design'd to bring us to that study we neglect for it : which is not onely not to use him as a benefactor , but as if he meant to punish him ( if i may so speak ) for having oblieged us , since we so abuse some of his favours , as to make them inducements to our unthankful disregard of his intentions in the rest . and this ingratitude is the more culpable , because the laws of ingenuity , and of justice it self , charge us to glorifie the maker of all things visible , not onely upon our own account , but upon that of all his other works . for by gods endowing of none but man here below with a reasonable soul , not onely he is the sole visible being that can return thanks and praises in the world , and thereby is oblieged to do so , both for himself , and for the rest of the creation ; but 't is for mans advantage , that god has left no other visible beings in the world , by which he can be studied and celebrated . for , reason is such a ray of divinity , that , if god had vouchsafed it to other parts of the universe besides man , the absolute empire of man over the rest of the world must have been shar'd , or abridg'd . so that he , to whom it was equally easie to make creatures superior to man ( as the scripture tells us of legions , and myriads of angels ) as to make them inferiour to him , dealt so obligingly with mankind , as rather to trust ( if i may so speak ) our ingenuity , whether he shall reap any celebrations from the creatures we converse with , than lessen our empire over them , or our prerogatives above them . but i fear , that , notwithstanding all the excellency of reveal'd truths , and consequently of that onely authentic repository of them , the scripture , you , as well as i , have met with some ( for i hope there are not many ) virtuosi , that think to excuse the neglect of the study of it , by alledging , that to them who are lay-men , not ecclesiasticks , there is requir'd to salvation the explicit knowledge but of very few points , which are so plainly summ'd up in the apostles creed , and are so often and conspicuously set down in the scripture , that one needs not much search or study it to find them there . in answer to this allegation , i readily grant , that through the great goodness of god , who is willing to have all men saved , and come to the knowledge of the truth , that is necessary to be so , there are much fewer articles absolutely necessary to be by all men distinctly believed , than may be met with in divers long confessions of faith , some of which have , i fear , less promoted knowledge than impair'd charity . but then it may be also consider'd , . that 't is not so easie for a rational man , that will trouble himself to enquire no farther than the apostles creed , to satisfie himself upon good grounds , that all the fundamental articles of christianity are contain'd in it . . that the creed proposes onely the credenda , not the agenda of religion ; whereas the scriptures were designed , not onely to teach us what truths we are to believe , but by what rules we are to live ; the obedience to the laws of christianity being as necessary to salvation , as the belief of its mysteries . . that besides the things which are absolutely necessary , there are several that are highly useful , to make us more clearly understand , and more rationally and firmly believe , and more steadily practise , the points that are necessary . . and since , whether or no those words of our saviour to the jews , 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 , be to be rendred in the imperative or the indicative mode ; st. paul would have the word of christ to dwell richly in us , ( by which , whether he mean the holy scriptures then extant , or the doctrine of christ , is not here material ; ) thereby teaching us , that searching into the matters of religion may become necessary as a duty , though it were not otherwise necessary as a means of attaining salvation . and indeed 't is far more pardonable to want or miss the knowledge of truths , than to despise or neglect it . and the goodness of god to illiterate or mistaken persons , is to be suppos'd meant in pity to our frailties , not to encourage our laziness ; nor is it necessary , that he that pardons those seekers of his truths that miss them , should excuse those despisers that will not seek them . but whether or no by this design'd neglect of theology the persons , i deal with , do sufficiently consult their own safety , i doubt they will not much recommend their ingenuity . for to have received from god a greater measure of intellectual abilities than the generality of christians , and yet willingly to come short of very many of them , in the knowledge of the mysteries and other truths of christianity , which he often invites us , if not expresly commands , to search after , is a course that will not relish of over-much gratitude . is it a piece of that , and of ingenuity , to receive ones understanding and ones hopes of eternal felicity from the goodness of god , without being sollicitous of what may be known of his nature and purposes by so excellent a way as his own revelation of them ? to dispute anxiously about the properties of an atome , and be careless about the inquiry into the attributes of the great god , who formed all things ; to investigate the spontaneous generation of such vile creatures as insects , than the mysterious generation of the adorable son of god ; and , in a word , to be more concern'd to know every thing that makes a corporeal part of the world , than the divine and incorporeal authour of the whole ? and then , is it not , think you , a great piece of respect , that these men pay to those truths , which god thought fit to send sometimes prophets and apostles , sometimes angels , and sometimes his onely son himself to reveal , that such truths are so little valued by them , that rather than take the pains to study them , they will implicitly , and at adventures believe , what that society of christians , they chance to be born and bred in , have ( truly or falsly ) delivered concerning them ? and does it argue a due regard to points of religion , that those , who would not believe a proposition in staticks , perhaps about a meer point , the centre of gravity , or in geometry , about the properties of some nameless curve line , or some such other things , ( which to ignore , is usually not a blemish , and about which , to be mistaken , is more usually without danger , ) should yet take up the articles of faith , concerning matters of great and everlasting consequence , upon the authority of men , fallible as themselves , when satisfaction may be had without them from the infallible word of god ? in this very unlike those bereans , whom the evangelist honours with the title of noble , that when the doctrines of the gospel were proposed to them , they searched the scriptures daily , whether those things were so . again , if a man should refuse to learn to read any more , than just as much as may serve his turn , by intituling him to the benefit of the clergy , to save him from hanging , would these men think so small a measure of literature , as he had acquir'd on such an account , could prove that man to be a lover of learning ; and yet a neglecter of the study of all not absolutely necessary-divine truths , during ones life , because the belief of the articles of the creed may make a shift to keep him from being doom'd to hell for ignorance after his death , will not by ( what in a learned man must be ) so pitiful a degree of knowledge be much better intitled to that ingenuous love of god and his truths , that becomes a rational creature and a christian . the antient prophets , though honour'd by god with direct illuminations , were yet very solicitous to find out and learn the very circumstances of the evangelical dispensations , which yet they did not know . and some of the gospel mysteries are of so noble and excellent a nature , that the angels themselves desire to look into them . and though all the evangelical truths are not precisely necessary to be known , it may be both a duty not to despise the study of them , and a happiness to employ our selves about it . it was the earnest prayer of a great king , and no less a prophet , that his eyes might be opened to behold ( not the obvious and necessary truths , but ) the wondrous things of gods law. he is pronounced happy in the beginning of the apocalypse , that reads and observes the things contain'd in that dark and obscure part of scripture . and 't is not onely those truths that make articles of the creed , but divers other doctrines of the gospel , that christ himself judged worthy to be concluded with this epiphonema , he that hath ears to hear , let him hear ; on which the excellent grotius makes this just paraphrase , intellectus nobis à deo potissimum datus est , ut eum intendamus documentis ad pietatem pertinentibus the third section . i come now to our third and last inducement to the study of divine things , which consists in , and comprises the advantages of that study , which do as much surpass those of all other contemplations , as divine things transcend all other objects . and indeed , the utility of this study is so pregnant a motive , and contains in it so many invitations , that your friend must have as little sense of interest as of gratitude , if he can neglect such powerful and such ingaging invitations . for , in the first place , theological studies ought to be highly endeared to us by the delightfulness of considering such noble and worthy objects as are therein propos'd . the famous answer given by an excellent philosopher , who being ask'd what he was born for , repli'd , to contemplate the sun , may justly recommend their choice , who spend their time in contemplating the maker of the sun , to whom that glorious planet it self is but a shadow . and perhaps that philosopher failed more in the instance than in the notion : for his answer implies , that man's end and happiness consists in the exercise of his noblest faculties on the noblest objects . and surely the seat of formal happiness being the soul , and that happiness consequently consisting in the operations of her faculties ; as the supreme faculty of the mind is the understanding , so the highest pleasures may be expected from the due exercise of it upon the sublimest and worthiest objects . and therefore i wonder not , that though some of the school-men would assign the will a larger share in mans felicity , than they will allow the intellect ; yet the generality of them are quite of another mind , and ascribe the preheminence in point of felicity to the superiour faculty of the soul. but , whether or no this opinion be true in all cases , it may at least be admitted in ours : for , the chief objects of a christian philosophers contemplation , being as well the infinite goodness , as the other boundless perfections of god , they are naturally fitted to excite in his mind an ardent love of that adorable being , and those other joyous affections and virtuous dispositions , that have made some men think happiness chiefly seated in the will. but having intimated thus much by the way , i pass on to add , that the contentment afforded by the assiduous discovery of god and divine mysteries , has so much of affinity with the pleasures , that shall make up mens blessedness in heaven it self , that they seem rather to differ in degree than in kind . for , the happy state even of angels is by our saviour represented by this imployment , that they continually see the face of his father who is in heaven . and the same infallible teacher , intending elsewhere to express the celestial joys that are reserv'd for those , who for their sake deny'd themselves sensual pleasures , imploys the vision of god as an emphatical periphrase of felicity , blessed , said he , are the pure in heart , for they shall see god. and as aristotle teaches , that the soul doth after a sort become that which it speculates , st. paul and st. john assure us , that god is a transforming object , and that in heaven we shall be like him , for ( or , because ) we shall see him as he is . and though i readily admit , that this beatisick vision of god , wherein the understanding is the proper instrument , includes divers other things which will concur to the compleat felicity of the future life ; yet i think , we may be allowed to argue , that that ravishing contemplation of divine objects , will make no small part of that happy estate , which in these texts take its denomination from it . i have above intimated , that the scripture attributes to the angels themselves transports of wonder and joy upon the contemplation of god , and the exercises they consider of his wisdom , justice , or some other of his attributes . but least in referring you to the angels , you should say , that i do in this discourse lay aside the person of a naturalist , in favour of divines ; i will refer you to des cartes himself , whom i am sure your friend will allow to have been a rigid philosopher , if ever there were any . thus then speaks he in that treatise , where he thinks he imploys a more than mathematical rigor ; and where he was obliged to utter those ( i had almost said passionate ) words , i am going to cite from him , onely by the impressions made on him by the transcendent excellency of the ob●●… he contemplated ; sed priusquam ( says he ) hoc diligentius examinem , simulque in alias veritates quae inde colligi possunt , inquiram , placet hic aliquandiu in ipsius dei contemplatione immorari , ejus attributa apud me expendere , & immensi hujus luminis pulchritudinem , quantum caligantis ingenii mei acies ferre poterit , intueri , admirari , adorare . ut enim in hac sola divinae majestatis contemplatione summam alterius vitae felicitatem ex consistere fide credimus ; ita etiam jam ex eadem , licet multo minus perfecta , maximam , cujus in hac vita capaces simus , voluptatem , percipi posse experimur . but as high a satisfaction as the study of divine things affords by the nobleness of its object , the contentment is not much inferiour that accrues from the same study upon the score of the sense of a mans having in it performed his duty . to make actions of this nature satisfactory to us , there is no need , that the things we are employ'd about , should in themselves be excellent or delightful ; the inward gratulations of conscience for having done our duties is able to ●●…d the bitterest pills , and , like the wood that grew by the waters of marah , to correct and sweeten that liquor , which before was the most distastful . those antient pagan heroes , whose vertues may make us blush , being guided but by natural reason , and innate principles of moral virtues , could find the most difficult and most troublesome duties , upon the bare account of their being duties , not onely tolerable but pleasant . and though to deny some lusts be , in our saviours esteem , no less uneasie , then for a man to pluck out his right eye , or cut off his right hand ; yet even ladies have with satisfaction chosen , not onely to deny themselves the greatest pleasures of the senses , but to sacrifice the seat of them , the body it self , to preserve the satisfaction of being chaste . nor are they onely the dictates of obedience that we comply with in this study , but those of gratitude ; and that is a vertue that has so powerful an ascendant upon ingenuous minds , that those , whose principles and aims were not elevated by religion , have , in acknowledgment to their parents and their countrey , courted the greatest hardships , and hazards , and sufferings , as if they were as great delights and advantages . and a gratefull person spends no part of his life to his greater satisfaction , than that which he ventures or imploys for those to whom he is oblieged for it ; and oftentimes finds a greater contentment even in the difficultest acknowledgments of a favour , than he did in receiving of it . another advantage , and that no mean one , that may accrue from the contemplation of theological truths , is , the improvement of the contemplator himself in point of piety and virtue . for , as the gospel is styl'd , the mystery of godliness ; and st. paul elsewhere calls what it teaches , the truth which is according to godliness , that is , a doctrine fram'd and fitted to promote the interest of piety and virtue in the world : so this character and encomium belongs ( though perhaps not equally ) to the more retir'd truths discover'd by speculation , as well as to those more obvious ones , that are familiarly taught in catechisms and confessions of faith. i would by no means lessen the excellency and prerogatives of fundamentals ; but , since the grand and noblest engagements to piety and virtue , are a high veneration for god and his christ , and an ardent love of them ; i cannot but think , that those particular inquiries , that tend to make greater discoveries of the attributes of god , of the nature , and offices , and life of our saviour , and of the wisdom and goodness they have display'd in the contrivance and effecting of man's redemption ; do likewise tend to increase our admiration , and inflame our love , for the possessors of such divine excellencies , and the authors of such invaluable benefits . and as the brazen serpent , that was but a type of one of the gospel mysteries , brought recovery to those that look'd up to it ; so the mysteries themselves , being duly consider'd , have had a very sanative influence on many that contemplated them. nor is it likely , that he that discerns more of the depth of gods wisdom and goodness , should not , caeteris paribus , be more disposed than others to admire him , to love him , to trust him , and so to resign up himself to be governed by him : which frame of mind both is it self a great part of the worship of god , and doth directly tend to the production and increase of those vertues , without the practise of which , the scripture plainly tells us , that we can neither obey god , nor express our love to him . and from this bettering of the mind by the study of theology , will flow ( to add that upon the by ) another benefit , namely , that by giving us a higher value for god and his truths , it will endear heaven to us , and so not onely assist us to come thither , but heighten our felicity there . i know it may be said , that the melioration of the mind is but a moral advantage . but give me leave to answer , that , besides that 't is such a moral advantage as supposes an intellectual improvement whose fruit it is , a moral benefit may be great enough , even in the judgment of a meer philosopher , and an epicurean , to deserve as much study as natural philosophy it self . and that you may not think that i speak this onely , because i write in this epistle as a friend to divines , i will tell you , that epicurus himself , who has now adays so numerous a sect of naturalists to follow him , studied physicks , and writ so many treatises about them for this end , that by knowing the natural causes of thunder , lightning , and other dreadful phaenomena , the mind might be freed from the disquieting apprehensions men commonly had , that such strange and formidable things proceeded from some incensed deity , and so might trouble the mind , as well as the air. this account i have been giving of epicurus his design , is but what seems plainly enough intimated by his own words , preserved us by laertius , near the end of his physiological epistle to herodotus , where recommending to him the consideration of what he had delivered about physical principles in general , and meteors in particular , he subjoyns , si enim ab istis non discesserimus , tum id unde oritur perturbatio , quodque metum ingerit , recta cum ratione edisseremus , nosque ab ipsis eximemus . and to this in the close of his meteorological epistle to pythocles , his best interpreter , gassendus , makes him speak consonantly , in these words , maxime veró dede teipsum speculationi principiorum , ex quibus constant omnia , & infinitatis naturae , aliorumque his cohaerentium insuper veró & criteriorum , affectuumque animi , & scopum illius in quem ista edisserentes collineavimus , attende , tranquillitatem intelligo statumque mentis imperturbatum . but this is not all the testimony i can give you from epicurus himself to the same purpose , for among his ratae sententiae , preserved us by laertius , ( himself reputed an epicurean ) i find one that goes further ; si nihil ( says he ) conturbaret nos quod suspicamur , veremu que ex rebus sublimibus , neque item quod ex ipsa morte , ne quando nimirum ad nos pertine at aliquid , ac nosse praeterea possemus , qui germani fines dolorum atque cupiditatum sint ( 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) nihil physiologiâ indigeremus . thus far the testimony of epicurus , of whose mind though i am not at all , as to what he would intimate , that physiology is either proper to free the mind from the belief of a provident deity , and the souls immortality , or fit for no other considerable purposes ; yet this use we may well make of these declarations , that , in epicurus's opinion , a moral advantage that relates to the government of the affections , may deserve the pains of making inquiries into nature . and since it hence appears , that a meer philosopher , who admitted no providence , may think it worth his pains , to search into the abstrusest parts of physicks , and the difficultest phaenomena of nature , onely to ease himself of one troublesome affection , fear ; it need not be thought unphilosophical , to prosecute a study , that will not onely restrain one undue passion , but advance all vertues , and free us from all servile fears of the deity ; and tend to give us a strong and well-grounded hope in him ; and make us look upon gods greatest power , not with terrour , but with joy. there is yet another advantage belonging to the study of divine truths , which is too great to be here pretermitted . for whereas there is scarce any thing more incident to us whilst we inhabit our ( batté chómer ) cottages of clay , and dwell in this vale of tears , than afflictions ; it ought not a little to endear to us the newly mention'd study , that it may be easily made to afford us very powerful consolations in that otherwise uneasie state . i know it may be said , that the speculations about which the naturalist is busied , are as well pleasing diversions , as noble imployments of the mind . and i deny not that they are often so , when the mind is not hinder'd from applying it self attentively to them ; so that afflictions slight and short may well be weather'd out by these philosophical avocations ; but the greater and sharper sort of afflictions , and the approaches of death , require more powerful remedies , than these diversions can afford us . for in such cases , the mind is wont to be too much discompos'd , to apply the attention requisite to the finding a pleasure in physical speculations ; and in sicknesses , the soul is oftentimes as indispos'd to relish the pleasures of meerly humane studies , as the languishing body is to relish those meats , which at other times were delightful : and there are but few that can take any great pleasure to study the world , when they apprehend themselves to be upon the point of being driven out of it , and in danger of losing all their share in the objects of their contemplation . it will not much qualifie our sense of the burning heat of a feaver , or the painful gripes of the cholick , to know , that the three angles of a triangle are equal to two right ones ; or that heat is not a real quality ( as the schools would have it , ) but a modification of the motion of the insensible parts of matter ; and pain not a distinct , inherent quality in the things that produce it , but an affection of the sentiment . the naturalists speculations afford him no consolations that are extraordinary in , or peculiar to , the state of affliction ; and the avocations they present him with , do rather amuse the mind from an attention to lesser evils , than bring it any advantages to remove or compensate them ▪ and so work rather in the nature of opiates , than of true cordials . but now , if such a person as dr. n. falls into adversity , the case is much otherwise ; for we must consider , that when the study of divine things is such as it ought to be , though , that in it self , or in the nature of the imployment , be an act or exercise of reason ; yet being apply'd to , out of obedience , and gratitude , and love to god , it is upon the account of its motives , and its aim , an act of religion ; and as it proceeds from obedience , and thankfulness , and love to god , so it is most acceptable to him ; and upon the account of his own appointment , as well as goodness , is a most proper and effectual means of obtaining his favour ; and then i presume , it will easily be granted , that he who is so happy as to enjoy that , can scarce be made miserable by affliction . for not now to enter upon the common-place of the benefits of afflictions to them that love god , and to them that are lov'd by him , it may suffice , that he who ( as the scripture speaks ) knows our frame , and has promised those that are his , that they shall not be over-burden'd , is dispos'd and wont to give his afflicted servants , both extraordinary comforts in afflictions , and comforts appropriated to that state . for though natural philosophy be like its brightest object , the stars , which , however the astronomer can with pleasure contemplate them , are unable , being meer natural agents , to afford him a kinder influence than usual , in case he be cast upon his bed of languishing , or into prison ; yet the almighty and compassionate maker of the stars , being not onely a voluntary , but the most free , agent , can suit and proportion his reliefs to our necessities , and alleviate our heaviest afflictions by such supporting consolations , that not onely they can never surmount our patience , but are oftentimes unable so much as to hinder our joy ; and when death , that king of terrours , presents it self , whereas the meer naturalist sadly expects to be depriv'd of the pleasure of his knowledge by losing those senses and that world , which are the instruments and the objects of it ; and perhaps ( discovering beyond the grave nothing but either a state of eternal destruction , or of eternal misery , ) fears either to be confin'd for ever to the sepulchre , or expos'd to torments that will make even such a condition desirable ; the pious student of divine truths , is not onely freed from the wracking apprehensions of having his soul reduc'd to a state of annihilation , or cast into hell , but enjoys a comfortable expectation of finding far greater satisfaction than ever in the study he now rejoyces to have pursu'd ; since the change , that is so justly formidable to others , will but bring him much nearer to the divine o●jects of his devout curiosity , and strangely elevate and inlarge his faculties to apprehend them . and this leads me to the mention of the last advantage belonging to the study i would perswade you to ; and indeed , the highest advantage that can recommend any study , or invite men to any undertaking ; for this is no less than the everlasting fruition of the divine objects of our studies hereafter , and the comfortable expectation of it here . for the employing of ones time and parts , to admire the nature and providence of god , and contemplate the divine mysteries of religion , as it is one of the chief of those homages and services , whereby we venerate and obey god ; so it is one of those , to which he hath been pleased to apportion no less a recompence , than ( that which can have no greater ) the enjoyment of himself . the saints and angels in heaven have divers of them been employ'd to convey the truths of theology , and are sollicitous to look into those sacred mysteries ; and god hath been pleased to appoint , that those men who study the same lessons that they do here , shall study them in their company hereafter . and doubtless , though heaven abound with unexpressible joys , yet it will be none of the least that shall make up the happiness even of that place , that the knowledge of divine things , that was here so zealously pursu'd , shall there be compleatly attain'd . for those things that do here most excite our desires , and quicken the curiosity and industry of our searches , will not onely there continue , but be improv'd to a far greater measure of attractiveness and influence . for all those interests , and passions , and lusts , that here below either hinder us from clearly discerning , or keep us from sufficiently valuing , or divert us from attentively enough considering , the beauty and harmony of divine truths , will there be either abolish'd , or transfigur'd : and as the object will be unveil'd ; so our eye will be enlighten'd , that is , as god will there disclose those worthy objects of the angels curiosity , so he will inlarge our faculties , to enable us to gaze without being dazl'd upon those sublime and radiant truths , whose harmony as well as splendor we shall be then qualifi'd to discover , and consequently with transports to admire . and this enlargement and elevation of our faculties , will , proportionably to its own measure , increase our satisfaction at the discoveries it will enable us to make . for theology is like a heaven , which wants not more stars than appear in it , but we want eyes , quick-sighted and piercing enough to reach them . and as the milky way , and other whiter parts of the firmament , have been full of immortal lights from the beginning , and our new telescopes have not plac'd , but found them , there ; so , when our saviour , after his glorious resurrection , instructed his apostles to teach the gospel , 't is not said that he alter'd any thing in the scriptures of moses and the prophets , but onely open'd and enlarg'd their intellects , that they might understand the scriptures : and the royal prophet makes it his prayer , that god would be pleased to open his eyes , that he might see wonderful things out of the law ; being ( as was above intimated ) so well satisfi'd , that the word of god wanted not admirable things , that he is onely sollicitous for the improvement of his own eyes , that they might be qualifi'd to discern them . i had almost forgotten one particular , about the advantages of theological studies , that is too considerable to be left unmention'd : for as great as i have represented the benefits accruing from the knowledge of divine truths ; yet to endear them to us , it may be safely added , that , to procure us these benefits , the actual attainment of that knowledge is not always absolutely necessary , but a hearty endeavour after it may suffice to entitle us to them . the patient chymist , that consumes himself and his estate in seeking after the philosophers stone , if he miss of his idoliz'd elixir , had as good , nay better , have never sought it , and remains as poor in effect , as he was rich in expectation . the husbandman that employs his seed and time , to obtain from the ground a plentiful harvest , if , after all , an unkind season happen , must see his toil made fruitless ; — longique perit labor irritus anni . too many patients , that have punctually done and suffer'd for recovery all that physicians could prescribe , meet at last with death in stead of health . you know what entertainment has been given by skilful geometricians to the laborious endeavours , even of such famous writers as scaliger , longomontanus , and other tetragonists ; and that their successor mr. hobbs , after all the ways he has taken , and those he has propos'd , to square the circle , and double the cube , by missing of his end , has , after his various attempts , come off , not onely with disappointment , but with disgrace . and ( to give an instance even in things celestial ) how much pains has been taken to find out longitudes , and make astrological precictions with some certainty , which for want of coming up to what they aimed at , have been useless , if not prejudicial to the attempters . but god ( to speak with st. paul on another occasion ) that made the world , and all things therein , and is lord of heaven and earth , seeks not our services , as though he needed any thing , seeing he giveth life , and breath , and all things : his self-sufficiency and bounty are such , that he seeks in our obedience the occasions of rewarding it , and prescribes us services , because the practise of them is not onely sutable to our rational nature , but such as will prevail with his justice , to let his goodness make our persons happy . agreeably to this doctrine we find in the scripture , that abraham is said to have been justified by faith , when he offered his son isaac upon the altar , ( though he did not actually sacrifice him ) because he endeavour'd to do so ; although , god graciously accepting the will for the deed , accepted also of the bloud of a ram instead of isaac's . and thus we know , that 't was not david , but solomon that built the temple of hierusalem , and yet god says to the former of those kings ( as we are told by the latter ) for asmuch as it was in thine heart to build an house for my name thou didst well in that it was in thine heart ; notwithstanding thou shalt not build the house , &c. and if we look to the other circumstances of this story , as they are delivered in the second book of samuel , we shall find , that upon david's declaration of a design to build god an house , god himself vouchsafes to honour him , as he once did moses , with the peculiar title of his servant ; and commands the prophet to say to him , also the lord tells thee , that he will make thee an house : to which is added one of the graciousest messages that god ever sent to any particular man. by which we may learn , that god approves and accepts even those endeavours ( of his servants ) if they be real and sincere , that never come to be actually accomplished : good designs and endeavours are our part , but the events of those , as of all other things , are in the all-disposing hand of god , who , if we be not wanting to what lies in us , will not suffer us to be losers by the defeating dispositions of his providence ▪ but crown our endeavours either with success , or with some other recompence , that will keep us from being losers by missing of that . and indeed , if we consider the great elogies that the scripture , as well frequently as justly , gives god's goodness ( which it represents as over , or as above , all his works ) and that his purer eyes punish , as well as see , the murder and adultery of the heart , when those intentional sins are hinder'd from advancing into actual ones ; we can scarce doubt but he , whose justice punishes sinful aims , will allow his infinite goodness to recompense pious attempts : and therefore our saviour pronounces them blessed , that hunger and thirst after righteousness , assuring them that they shall be satisfi'd , and thereby sufficiently intimating to us , that an earnest desire after a spiritual grace ( and such is the knowledge of divine things ) may entitle a man to the complete possession of it , if not in this life , yet in the next , where we shall not any more walk by faith , but by sight , and obtain as well a knowledge as other endowments , befitting that glorious state , wherein the purchaser of it for us , assures us , that we shall be [ 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ] equal , or like to the angels . the considerations , sir , i have hitherto laid before you , to recommend the study of divine truths , have , i hope , perswaded you , that 't is on many accounts both noble and eligible in it self ; and therefore i shall here conclude the first part of this discourse . and in regard that the undervaluation physiophilus expresses for that excellent imployment , seems to flow ( chiefly at least ) from his fondness and partiality for natural philosophy ; it will next concern us to compare the study of theology with that of physicks , and show , that the advantages which your friend alledges in favour of the latter , are partly much lessen'd by disadvantageous circumstances , and partly much out-weigh'd by the transcendent excellencies of theological contemplations : the study whereof will thereby appear to be not onely eligible in it self , but preferrible to its rival . and i must give you warning to expect to find the second part , which the making this comparison challenges to it self , a good deal more prolix than the first ; not onely because it often requires more trouble , and more words to detect and disprove an errour , than to make out a truth ; but also because that divers things tending to the credit of divinity , and which consequently might have been brought into the first part of this discourse , were thought more fit to be interwoven with other things , in the answers made to the objections examin'd in the second . the excellency of theology : or , the preeminence of the study of divinity , above that of natural philosophy . the second part . i shall , without preamble , begin this discourse , by considering the delightfulness of physicks , as the main thing that inveigles your friend , and divers other virtuosi , from relishing , as they ought , and otherwise would , the pleasantness of theological discoveries . and to deal ingenuously with you , i shall not scruple to acknowledge , that though the address i have made to nature has lasted several years , and has been toilsome enough , and not unexpensive ; yet i have been pleas'd enough with the favours , such as they are , that she has from time to time accorded me , not to complain of having been unpleasantly imploy'd . but though i readily allow the attainments of naturalists to be able to give philosophical souls sincerer pleasures , than those that the more undiscerning part of mankind is so fond of ; yet i must not therefore allow them to surpass , or even equal , the contentment , that may accrue to a soul qualified by religion , to relish the best things most from some kind of theological contemplations . this , i presume , will sufficiently appear , if i shew you , that the study of physiology is not unattended with considerable inconveniencies , and that the pleasantness of it may be , by a person studious of divinity , enjoy'd with endearing circumstances . but before i name any of the particular reasons that i am to represent , i fear it may be requisite to interpose a few words , to obviate a mistake , which , if not prevented , may have an ill aspect , not onely upon the first section , but upon a great part of the following discourse . for i know that it may be said , that whereas i alledge divers things , to lessen the lately mentioned delightfulness of the study of physic , and to depreciate some other advantages , by which the following sections would recommend it , some of the same things may be objected against the delightfulness of the study of divinity . but this objection will not , i presume , much move you , if you consider the argument and scope of the two parts of this letter . for in the former i have shewn by positive proofs , that the study of theology is attended with divers advantages , which belong to it , either onely as some of them do , or principally as others . and now in the second part i come to consider , whether what is alledged in behalf of the study of philosophy , deserve to counter-ballance those prerogatives or advantages ; and therefore it neither need be , nor is my design , to compare , for instance , the delightfulness of the two studies , philosophy and physicks , but by shewing the inconveniences that allay the latter , to weaken the argument that is drawn from that delightfulness , to conclude it preferrable to the study of theology . so that my work , in this and the following sections , is , not so much to institute comparisons , as to obviate or answer allegations . for since i have in the past discourse grounded the excellency of the study of divinity , chiefly upon those great advantages that are peculiar to it ; my reasonings would not be frustrated , though it should appear , that in point of delightfulness , certainty , &c. that study should , in many cases , be liable to the same objections with the study of nature , since 't is not mainly for these qualities , but , as i was saying , for other and peculiar excellencies that i recommended divinity , and therefore , supposing the delightfulness , &c. of that and of physicks , to be allayed by the same , or equal inconveniences or imperfections ; that supposition would not hinder the scales to be swayed in favour of divinity , upon the score of those advantages that are unquestion'd , and peculiarly belong to it . i know not whether i need add , that , notwithstanding this , you are not to expect , that i should give philosophy the wounds of an enemy . for my design being not to discourage you , nor any ingenious man , from courting her at all , nor from courting her much , but from courting her too much , and despising divinity for her , i employ against her not a sword to wound her , but a ballance , to shew , that her excellencies , though solid and weighty , are less so , than the preponderating ones of theology . and this temper and purpose of mine renders my task difficult enough to have , perhaps , some right to your pardon ▪ as well as some need of it , if i do not every where steer so exactly , as equally to avoid injuring the cause i am to plead for , and disparaging a study , which i would so little depreciate , that i allow it a great part of my inclinations , and not a little share of my time. and having said this , to keep the design of this discourse from being misunderstood , i hope we may now proceed to the particulars , whose scope we have been declaring . returning then to what i was about to say before this long , but needful , advertisement interrupted me , i shall resume my discourse of the delightfulness of the study of physicks , about which i was going in the first place to tell you , that i know you and your friend will freely grant me , that the knowledge of the empty and barren physiology , that is taught in the schools , as it exacts not much pains to be acquir'd , so it affords but little satisfaction when attain'd . and as i know you will give me leave to say this ; so , being warranted by no slight experience of my own , i shall take leave to say also , that the study of that experimental philosophy , which is that whereof your friend is so much enamour'd , is , if it be duly prosecuted , a very troublesome and laborious imployment . for , ( to mention at present but this ) that great variety of objects the naturalist is not onely by his curiosity , but by their secret dependances upon one another , engag'd to consider , and several ways to handle , will put him upon needing , and consequently upon applying himself to such a variety of mechanick people , ( as distillers , drugsters , smiths , turners , &c. ) that a great part of his time , and perhaps all his patience , shall be spent in waiting upon trades-men , and repairing the losses he sustains by their disappointments , which is a drudgery greater than any , who has not try'd it , will imagine , and which yet being as inevitable as unwelcome , does very much counter-ballance and allay the delightfulness of the study we are treating of . in which so great a part of a mans care and time must be laid out in providing the apparatus'es necessary for the trying of experiments . but this is not all . for when you have brought an experiment to an issue , though the event may often prove such as you will be pleas'd with ; yet it will seldome prove such as you can acquiesce in . for it fares not with an inquisitive mind in studying the book of nature , as in reading of aesop's fables , or some other collection of apologues of differing sorts , and independant one upon another ; where when you have read over as many at one time as you think fit , you may leave off when you please , and go away with the pleasure of understanding those you have perus'd , without being sollicited by any troublesome itch of curiosity to look after the rest , as those which are needful to the better understanding of those you have already gone over , or that will be explicated by them , and scarce without them . but in the book of nature , as in a well contriv'd romance , the parts have such a connection and relation to one another , and the things we would discover are so darkly or incompleatly knowable by those that precede them , that the mind is never satisfied till it comes to the end of the book ; till when all that is discover'd in the progress , is unable to keep the mind from being molested with impatience to find that yet conceal'd , which will not be known till one does at least make a further progress . and yet the full discovery of natures mysteries , is so unlikely to fall to any mans share in this life , that the case of the pursuers of them is at best like theirs , that light upon some excellent romance , of which they shall never see the latter parts . for indeed ( to speak now without a simile ) there is such a relation betwixt natural bodies , and they may in so many ways ( and divers of them unobserv'd ) work upon , or suffer from , one another , that he who makes a new experiment , or discovers a new phaenomenon , must not presently think , that he has discover'd a new truth , or detected an old error . for , ( at least if he be a considering man ) he will oftentimes find reason to doubt , whether the experiment or observation have been so skilfully and warily made in all circumstances , as to afford him such an account of the matter of fact , as a severe naturalist would desire . and then , supposing the historical part no way defective , there are far more cases than are taken notice of , wherein so many differing agents may produce the exhibited phaenomenon , or have a great influence upon the experiment or observation , that he must be less jealous than becomes a philosopher , to whom experiments doe not oftentimes as well suggest new doubts , as present new phaenomena . and even those trials , that end in real discoveries , do , by reason of the connection of physical truths , and the relations that natural bodies have to one another , give such hopes and such desires of improving the acquists we have already made , to the explicating of other difficulties , or the making of further discoveries , that an inquisitive naturalist finds his work to increase daily upon his hands , and the event of his past toils , whether it be good or bad , does but engage him into new ones , either to free himself from his scruples , or improve his successes . so that , though the pleasure of making physical discoveries , is , in it self consider'd , very great ; yet this does not a little impair it , that the same attempts which afford that delight , do so frequently beget both anxious doubts , and a disquieting curiosity . so that , if knowledge be , as some philosophers have styl'd it , the aliment of the rational soul , i fear i may too truly say , that the naturalist is usually fain to live upon sallads and sauces , which though they yield some nourishment , excite more appetite than they satisfie , and give us indeed the pleasure of eating with a good stomach , but then reduce us to an unwelcome necessity of always rising hungry from the table . of divers things , that lessen the delightfulness of physiological studies , i do so amply discourse in other papers , that i might well remit you thither ; but indeed it is not necessary that i should insist on this argument any further . 't is true , that such a reference might be very proper , if the mysteries of theology and physick were like those of theology and necromancy , or some other part of unlawful magick , whereof the former could not be well relish'd without an abhorrence of the latter . but as the two great books , of nature and of scripture , have the same authour ; so the study of the latter does not at all hinder an inquisitive man's delight in the study of the former . the doctor i am pleading for , may as much relish a physical discovery , as physiophilus ; nay , by being addicted to theology and religion , he is so far from being uncapable of the contentments accruing from the study of nature , that beside those things that recommend it to others , there are several things that peculiarly endear it to him. for i. he has the contentment to look upon the wonders of nature , not onely as the productions of an admirably wise author of things , but of such an one as he intirely honours and loves , and to whom he is related . he that reads an excellent book , or sees some rare engine , will be otherwise affected with the sight or the perusal , if he knows it to have been made by a friend , or a parent , than if he considers it but as made by a stranger , whom he has no particular reason to be concern'd for . and if rehoboam did not as well degenerate from the sentiments of mankind , as from his family , he could not but look upon that magnificent temple of solomon with another eye , than did the throngs of strangers that came onely to gaze at it , as an admirable piece of architecture , whilst he consider'd that 't was his father that built it . and if ( as we see ) the same heroick actions , which we read in history , of some great monarch , that strangers barely and unconcernedly admire , the natives of his countrey do not onely venerate , but affectionately interest themselves therein , because they are his countrey-men , and their ancestors were his subjects : how much may we suppose the same actions would affect them , if they had the honour to be that prince's children ? we may well therefore presume , that 't is not without a singular satisfaction , that the contemplator , we are speaking of , does in all the wonders of nature discover , how wise , and potent , and bountiful that author of nature is , in whom he has a great interest , and that so great an one , as both to be admitted into the number of his friends , and adopted into the number of his sons , and is thereby in some measure concern'd in all the admirations and praises , that are paid either by himself or others , to those adorable attributes that god has displayed in that great master-piece of power and wisdom , the world. and when he makes greater discoveries in these expresses and adumbrations of the divine perfections , the delightfulness of his contemplation is proportionably increas'd upon such an account , as that , which indears to the passionate lover of some charming beauty an excellent , above an ordinary , picture of her ; because that the same things that make him , as it does other gazers , look upon it as a finer piece , make him look upon it as the more like his mistress , and thereby entertain him with the sublimer idea's of the belov'd original ; to whose transcendent excellencies he supposes that the noblest representations must be the most resembling . and there is a farther reason , why our contemplator should find a great deal of contentment in these discoveries . for we have in our nature so much of imperfection , and withall so much of inclination to self-love , that we do too confidently proportion our idea's of what god can do for us , to what we have already the knowledge or the possession of . and though , when we make it our business , we are able with much ado somewhat to enlarge our apprehensions , and raise our expectations beyond their wonted pitch ; yet still they will be but scantly promoted and heightned , if those things themselves be but mean and ordinary , which we think we have done enough if we make them surpass . a countrey villager , born and bred in a homely cottage , cannot have any suitable apprehensions of the pleasures and magnificence of a great monarchs court. and if he should be bid to scrue up his imagination to frame idea's of them , they would be borrow'd from the best tiled house he had seen in the market-towns where he had sold his turnips or corn , and the wedding-feast of some neighbouring farmers daughter . and though a child in the mother's womb had the perfect use of reason , yet could it not in that dark cell have any idea's of the sun or moon , or beauties or banquets , or algebra or chymistry , and many other things , which his elder brothers , that breath fresh air , and freely behold the light , and are in a more mature estate , are capable of knowing and enjoying . now among thinking men , whose thoughts run much upon that future state which they must shortly enter into , but shall never pass out of ; there will frequently and naturally arise a distrust , which though seldome own'd , proves oftentimes disquieting enough ! for such men are apt to question , how the future condition which the gospel promises , can afford them so much happiness as it pretends to ; since they shall in heaven but contemplate the works of god , and praise him , and converse with him , all which they think may , though not immediately , be done by men here below , without being happy : but he that by telescopes and microscopes , dexterous dissections , and well imploy'd furnaces , &c. discovers , the wondrous power and skill of him that contriv'd so vast and immense a mass of matter , into so curious a piece of workmanship as this world , will pleasingly be convinc'd of the boundless power and goodness of the great architect . and when he sees how admirably every animal is furnish'd with parts requisite to his respective nature ; and that there is particular care taken , that the same animal , as for example , man , should have differing provisions made for him according to his differing states within the womb , and out of it , ( a humane egg , and an embrio , being much otherwise nourished and fitted for action , than is a ( compleat ) man ; ) he , i say , who considers this , and observes the stupendious providence , and excellent contrivances , that the curious priers into nature ( and none but they ) can discover , will be as well enabled as invited to reason thus within himself : that sure god , who has with such admirable artifice fram'd silk-worms , butterflies , and other meaner insects , and with such wonderful providence taken care , that the nobler animals should as little want any of all the things requisite to the compleating of their respective natures ; and who , when he pleases , can furnish some things with qualifications , quite differing from those which the knowledge of his other works could have made us imagine , ( as is evident in the load-stone and in quick-silver among minerals , and the sensitive plant among vegetables , the camelion among animals , &c. ) this god , i say , must needs be fully able to furnish those he delights to honour ▪ with objects suitable to their improv'd . faculties , and with all that is requisite to the happiness he intends them in their glorifi'd state ; and is able to bring this to pass by such amazing contrivances , as perhaps will be quite differing from any , that the things we have yet seen suggest to us any idea's of . and sure he , that has in so immense , so curious , and so magnificent a fabrick , made such provision for men , who are either desperately wicked , or but very imperfectly good , and in a state where they are not to enjoy happiness , but by obedience and sufferings to fit themselves for it , may safely be trusted with finding them in heaven imployments and delights becoming the felicity he designs them there ; as we see that here below , he provides as well for the soaring eagle , as for the creeping caterpillar , ( and is able to keep the ocean as fully supply'd with rivers , as lakes or ponds are with springs and brooks . ) and as a state of celestial happiness is so great a blessing , that those things that afford us either greater assurances , or greater foretastes of it , are of the number of the greatest contentments and advantages , that short of it we can enjoy ; so 't is hard for any divine to receive so much of this kind of satisfaction , as he who by skilfully looking into the wonders of nature , has his apprehensions of god's power and manifold wisdom ( as an apostle calls it ) elevated and enlarg'd . as when the queen of sheba had particularly survey'd the astonishing prudence that solomon display'd in the ordering of his magnificent court ; she transportedly concluded those servants of his to be happy enough to deserve a monarchs envy , that were allowed the honour and priviledge of a constant and immediate attendance on him . the second section . i doubt not but you have too good an opinion of your friend , not to think that you may alledge in his favour , that the chief thing which makes him prefer physiology to all other kind of knowledge , is , that it enables those who are proficients in it to do a great deal of good , both by improving of trades , and by promoting of physick it self . and i am too mindful of what i writ to pyrophilus , to deny , either that it can assist a man to advance physick and trades , or that , by so doing , he may highly advantage mankind . and this , i , ( who would not lessen your friends esteem for physicks , but onely his partiality ) willingly acknowledge to be so allowable an endearment of experimental philosophy , that i do not know any thing , that to men of a humane , as well as ingenious disposition , ought more to recommend the study of nature ; except the opportunity it affords men to be just and grateful to the author both of nature and of man. i do not then deny , that the true naturalist may very much benefit mankind ; but i affirm , that , if men be not wanting to themselves , the divine may benefit them much more . it were not perchance either unseasonable , or impertinent to tell you on this occasion , that he who effectually teaches men to subdue their lusts and passions , does as much as the physician contribute to the preservation of their bodies , by exempting them from those vices , whose no less usual than destructive effects are wars , and duels , and rapines , and desolations , and the pox , and surfets , and all the train of other diseases that attend gluttony and drunkenness , idleness and lust ; which are not enemies to mans life and health barely upon a physical account , but upon a moral one , as they provoke god to punish them with temporal as well as spiritual judgments ; such as plagues , wars , famines , and other publick calamities , that sweep away a great part of mankind ; besides those personal afflictions of bodily sickness , and disquiets of conscience , that do both shorten mens lives , and imbitter them . whereas piety having ( as the scripture assures us ) promises both of this life , and of that which is to come , those teachers that make men virtuous and religious , by making them temperate , and chaste , and inoffensive , and calm , and contented , do not onely procure them great and excellent dispositions to those blessings , both of the right hand and of the left , which god's goodness makes him forward to bestow on those , who by grace and virtue are made fit to receive them ; but do help them to those qualifications , that by preserving the mind in a calm and cheerful temper , as well as by affording the body all that temperance can confer , do both lengthen their lives , and sweeten them . these things , i say , 't were not impertinent to insist on , but i will rather chuse to represent to you , that the benefits which men may receive from the divine , surpass those which they receive from the naturalist , both in the nobleness of the advantages , and in the duration of them . be it granted then , that the naturalist may much improve both physick and trades ; yet since these themselves were devised for the service of the body , ( the one to preserve or restore his health , and the other to furnish it with accommodations or delights ; ) the boasted use of natural philosophy , by its advancing trades and physick , will still be to serve the body ; which is but the lodging and instrument of the soul , and which , i presume , your friend , and which i am sure your self , will be far from thinking the noblest part of man. i know it may be said , nor do i deny it , that divers mechanical arts are highly beneficial , not onely to the inventors , but to those places , and perhaps those states , where such improvements are found out and cherish'd . but though i most willingly grant , that this consideration ought to recommend experimental philosophy , as well to states as to private persons ; yet , besides that many of these improvements do rather transfer than increase mankind's goods , and prejudice one sort of men as much as they advantage another , ( as in the case of the eastern spices , of whose trade the portugals and dutch by their later navigations , did , by appropriating it to themselves , deprive the venetians ) or else does but increase that , which , though very beneficial to the producers , is not really so to mankind in general : of which we have an example in the invention of extracting gold and silver out of the oar , with mercury . for though it have vastly enrich'd the spaniards in the west indies , yet 't is not of any solid advantage to the world ; no more than the discovery of the peruvian and other american mines ; by which , ( especially reckoning the multitudes of unhappy men that are made miserable , and destroyed in working them , ) mankind is not put into a better condition than it was before . and if the philosopher's stone it self , ( supposing there be such a thing ) were not an incomparable medicine , but were onely capable of transmuting other metalls into gold , i should perhaps doubt , whether the discoverer of it would much advantage mankind ; there being already gold and silver enough to maintain trade and commerce among men ; and for all other purposes , i know not , why a plenty of iron , and brass , and quick-silver , which are far more useful metalls , should not be more desirable . but not to urge this ; we may consider , that these advancements of inriching trades do still bring advantages but to the outward man , and those many arts and inventions that aim at the heightning the pleasures of the senses , belong but to the body ; and even in point of gratifying that , are not so requisite and important , as many suppose : education , custome , &c. having a greater interest than most imagine in the rellish men have even of sensitive pleasures . and as for physick , not to mind you , that it has been lowdly ( how justly , i here examine not , ) complain'd of , that the new philosophy has made it far greater promises than have yet been perform'd ; i shall onely take notice , that since all that physick is wont to pretend to , is , to preserve health , or restore it , there are multitudes in the world that have no need of the assistance the naturalist would give the physician ; and a healthy man , as such , is already in a better condition , than the philosopher can hope to place him in , and is no more advantag'd by the naturalist's contribution to physick , than a sound man that sleeps in a whole skin , is by all the fine tools of a chirurgeons case of instruments , and the various compositions of his chest . and as the benefits that may be derived from theology , much surpass those that accrue from physicks , in the nobleness of the subject they relate to ; so have they a great advantage in point of duration . for all the service that medicines , and engines , and improvements can do a man , as they relate but to this life , so they determine with it . physick indeed and chymistry do , the one more faintly , and the other more boldly , pretend sometimes not onely to the cure of diseases , but the prolongation of life : but since none will suspect , but that the masters of those parts of knowledge would employ their utmost skill to protract their own lives , those that remember , that solomon and helmont liv'd no longer , than millions that were strangers to philosophy ; and that even paracelsus himself , for all his boasted arcana , is by helmont and other chymists confessed to have died some years short of ; we may very justly fear , that nature will not be so kind to her greatest votaries , as to give them much more time than other men , for the payment of the last debt all men owe her . and if a few years respite could by a scrupulous and troublesome use of diet and remedies be obtain'd ; yet that , in comparison of the eternity that is to follow , is not at all considerable . but , whereas within no great number of years , ( a little sooner , or a little later ) all the remedies , and reliefs , and pleasures , and accommodations , that philosophical improvements can afford a man , will not keep him from the grave , ( which within very few days will make the body of the greatest virtuoso as hideous and as loathsome a carcase as that of any ordinary man ; ) the benefits that may accrue to us by divinity , as they relate chiefly , though not onely , to the other world ; so they will follow us out of this , and prove then incomparably greater than ever , when they alone shall be capable of being enjoy'd . so that philosophy , in the capacity we here consider it , does but as it were provide us some little conveniences for our passage ( like some accommodations for a cabbin , which out-lasts not the voyage , ) but religion provides us a vast and durable estate , or , as the scripture styles it , an unshaken kingdom , when we are arriv'd at our journeys end . and therefore the benefits accruing from religion , may well be concluded preferible to their competitors , since they not onely reach to the mind of man , but reach beyond the end of time it self ; whereas all the variety of inventions that philosophy so much boasts of , as whilst they were in season they were devis'd for the service of the body , so they make us busie , and pride our selves about things , that within a short time will not ( so much as upon its score ) at all concern us . the third section . i expect you should here urge on your friends behalf , that the study of physicks has one prerogative , ( above that of divinity , ) which , as it is otherwise a great excellency , so does much add to the delightfulness of it . i mean , the certainty , and clearness , and the thence resulting satisfactoriness of our knowledge of physical , in comparison of any we can have of theological matters , whose being dark and uncertain , the nature of the things themselves , and the numerous controversies of differing sects about them , sufficiently manifest . but upon this subject , divers things are to be consider'd . for first , as to the fundamental and necessary articles of religion , i do not admit the allegation , but take those articles to be both evident , and capable of a moral demonstration . and if there be any articles of religion , for which a rational and cogent proof cannot be brought , i shall for that very reason conclude , that such articles are not absolutely necessary to be believ'd ; since it seems no way reasonable to imagine , that god having been pleased to send not onely his prophets and his apostles , but his onely son into the world , to promulgate to mankind the christian religion , and both to cause it to be consign'd to writing , that it may be known , and to alter the course of nature by numerous miracles , that it might be believ'd ; it seems not reasonable , i say , to imagine , that he should not propose those truths , which he in so wonderful and so solemn a manner recommended , with at least so much clearness , as that studious and well-dispos'd readers may certainly understand such as are necessary for them to believe . . though i will not here engage my self in a disquisition of the several kinds , or , if you please , degrees , of demonstration , ( which yet is a subject that i judge far more considerable than cultivated , ) yet i must tell you , that as a moral certainty ( such as we may attain about the fundamentals of religion ) is enough in many cases for a wise man , and even a philopher to acquiesce in ; so that physical certainty , which is pretended for the truths demonstrated by naturalists , is , even where 't is rightfully claim'd , but an inferiour kind or degree of certainty , as moral certainty also is . for even physical demonstrations can beget but a physical certainty , ( that is , a certainty upon supposition that the principles of physick be true , ) not a metaphysical certainty , ( wherein 't is absolutely impossible , that the thing believ'd should be other than true . ) for instance , all the physical demonstrations of the antients about the causes of particular phaenomena of bodies , suppose , that ex nihilo nihil fit ; and this may readily be admitted in a physical sense , because according to the course of nature , no body can be produc'd out of nothing , but speaking universally it may be false , as christians generally , and even the cartesian naturalists , asserting the creation of the world , must believe , that , de facto , it is . and so whereas epicurus does , i remember , prove , that a body once dead cannot be made alive again , by reason of the dissipation and dispersion of the atoms , 't was , when alive , compos'd of ; though all men will allow this assertion to be physically demonstrable , yet the contrary may be true , if god's omnipotence intervenes , as all the philosophers that acknowledge the authority of the new testament , where lazarus and others are recorded to have been raised from the dead , must believe , that it actually did appear , and even all unprejudic'd reasoners must allow it to be possible , there being no contradiction impli'd in the nature of the thing . but now to affirm , that such things as are indeed contradictories cannot be both true , or , that factum infectum reddi non potest , are metaphysical truths , which cannot possibly be other than true , and consequently beget a metaphysical and absolute certainty . and your master cartesius was so sensible of a dependance of physical demonstrations upon metaphysical truths , that he would not allow any certainty not onely to them , but even to geometrical demonstrations , till he had evinc'd , that there is a god , and that he cannot deceive men that make use of their faculties aright . to which i may add , that even in many things that are look'd upon as physical demonstrations , there is really but a moral certainty . for when , for instance , des-cartes and other modern philosophers , take upon them to demonstrate , that there are divers comets that are not meteors , because they have a parallax lesser than that of the moon , and are of such a bigness , and some of them move in such a line , &c. 't is plain , that divers of these learned men had never the opportunity to observe a comet in their lives , but take these circumstances upon the credit of those astronomers that had such opportunities . and though the inferences , as such , may have a demonstrable certainty ; yet the premisses they are drawn from having but an historical one , the presumed physico-mathematical demonstration can produce in a wary mind but a moral certainty , and not the greatest neither of that kind that is possible to be attain'd ; as he will not scruple to acknowledge , that knows by experience , how much more difficult it is , than most men imagine , to make observations about such nice subjects , with the exactness that is requisite for the building of an undoubted theory upon them . and there are i know not how many things in physicks , that men presume they believe upon physical and cogent arguments , wherein they really have but a moral assurance ; which is a truth heeded by so few , that i have been invited to take the more particular notice of them in other papers , written purposely to show the doubtfulness and incompleatness of natural philosophy ; of which discourse , since you may command a sight , i shall not scruple to refer you thither for the reasons of my affirming here , that the most even of the modern virtuosi are wont to fancy more of clearness and certainty in their physical theories , than a critical examiner will find . onely that you may not look upon this as a put off , rather than a reference , i will here touch upon a couple of subjects , which men are wont to believe to be , and which indeed ought to be , the most throughly understood ; i mean the nature of body in general , and the nature of sensation . and for the first of these , since we can turn our selves no way , but we are every where environ'd , and incessantly touch'd by corporeal substances , one would think that so familiar an object , that does so assiduously , and so many ways affect our senses , and for the knowledge of which we need not inquire into the distinct nature of particular bodies , nor the properties of any one of them , should be very perfectly known unto us . and yet the notion of body in general , or what it is that makes a thing to be a corporeal substance , and discriminates it from all other things , has been very hotly disputed of , even among the modern philosophers , & adhuc sub judice lis est . and though your favourite des-cartes , in making the nature of a body to consist in extension every way , has a notion of it , which 't is more easie to find fault with , than to substitute a better ; yet i fear , 't will appear to be attended , not onely with this inconvenience , that god cannot , within the compass of this world , wherein if any body vanish into nothing , the place or space left behind it must have the three dimensions , and so be a true body , annihilate the least particle of matter , at least without , at the same instant and place , creating as much , ( which agrees very ill with that necessary and continual dependance , which he asserts matter it self to have on god for its very being ; ) but with such other inconveniences , that some friends of yours , otherwise very inclinable to the cartesian philosophy , know not how to acquiesce in it : and yet i need not tell you , how fundamental a notion the deviser of it asserts it to be . neither do i see , how this notion of a corporeal substance will any more , than any of the formerly received definitions of it , extricate us out of the difficulties of that no less perplexed , than famous controversie , de compositione continui . and though some ingenious men , who perhaps perceive better than others , how intricate it is , have of late endeavoured to shew , that men need not be sollicitous to determine this controversie , it not being rightly propos'd by the schoolmen that have started it ; and though i perhaps think , that natural philosophy may be daily advanc'd without the decision of it , because there is a multitude of considerable things to be discover'd and perform'd in nature , without so much as dreaming of this controversie ; yet still , as i would propose the question , the difficulties , till removed , will spread a thick night over the notion of body in general . for , either a corporeal and extended substance is ( either really or mentally ) divisible into parts endow'd with extension , and each of these parts is divisible also into other corporeal parts , lesser and lesser , in infinitum ; or else this subdivision must stop somewhere , ( for there is no mean between the two members of the distinction ; ) and in either case the opinion pitch'd upon will be liable to those inconveniences , not to say absurdities , that are rationally urg'd against it by the maintainers of the opposite ; the objections on both sides being so strong , that some of the more candid , even of the modern metaphysicians , after having tir'd themselves and their readers with arguing pro and con , have confess'd the objections on both sides to be insoluble . but though we do not clearly understand the nature of body in general ; yet sure we cannot but be perfectly acquainted with what passes within our selves in reference to the particular bodies we daily see , and hear , and smell , and taste , and touch. but alas , though we know but little , save by the informations of our senses ; yet we know very little of the manner by which our senses informs us . and to avoid prolixity , i will at present suppose with you , that the ingenious des cartes and his followers have given the fairest account of sensation , that is yet extant . now according to him , a man's body being but a well organiz'd statue , that which is truly called sensation is not perform'd by the organ , but by the mind , which perceives the motion produc'd in the organ ; ( for which reason he will not allow brutes to have sense properly so call'd ; ) so that if you ask a cartesian , how it comes to pass that the soul of man , which he justly asserts to be an immaterial substance , comes to be wrought upon , and that in such various manners , by those external bodies that are the objects of our senses , he will tell you , that by their impressions on the sensories , they variously move the fibres or threds of the nerves , wherewith those parts are endow'd , and by which the motion is propagated to that little kernel in the brain , call'd by many writers the conarion , where these differing motions being perceiv'd by the there residing soul , become sensations , because of the intimate union , and , as it were , permistion ( as cartesius himself expresses it ) of the soul with the body . but now , sir , give me leave to take notice , that this union of an incorporeal with a corporeal substance , ( and that without a medium ) is a thing so unexampled in nature , and so difficult to comprehend , that i somewhat question , whether the profound secrets of theology , not to say the adorable mystery it self of the incarnation , be more abstruse than this . for how can i conceive , that a substance purely immaterial , should be united without a physical medium , ( for in this case there can be none , ) with the body , which cannot possibly lay hold on it , and which it can pervade and flie away from at pleasure , as des-cartes must confess the soul actually does in death . and 't is almost as difficult to conceive , how any part of the body , without excepting the animal spirits , or the conarion , ( for these are as truly corporeal as other parts of the humane statue , ) can make impressions upon a substance perfectly incorporeal , and which is not immediately affected by the motions of any other parts , besides the genus nervosum . nor is it a small difficulty to a meer naturalist ( who , as such , does not in physical matters take notice of revelations about angels , ) to conceive how a finite spirit can either move , or , which is much the same thing , regulate and determine the motion of a body . but that which i would on this occasion invite you to consider , is , that supposing the soul does in the brain perceive the differing motions communicated to the outward senses ; yet this , however it may give some account of sensation in general , will not at all show us a satisfactory reason of particular and distinct sensations . for if i demand , why , for instance , when i look upon a bell that is ringing , such a motion or impression in the conarion produces in the mind that peculiar sort of perception , seeing , and not hearing ; and another motion , though coming from the same bell at the same time , produces that quite differing sort of perception that we call sound , but not vision ; what can be answered , but that it was the good pleasure of the author of humane nature to have it so ? and if the question be ask'd about the differing objects of any one particular sense ; as , why the great plenty of unperturbed light that is reflected from snow , milk , &c , does produce a sensation of whiteness , rather than redness or yellowness ? or why the smell of castor , or assa foetida , produces in most persons that which they call a stink , rather than a perfume ? ( especially since we know some hysterical women , that think it not onely a wholesome , but a pleasing smell . ) and if also you further ask , why melody and sweet things do generally delight us ? and discords and bitter things do generally displease us ? nay , why a little more than enough of some objects that produce pleasure , will produce pain ? ( as may be exemplifi'd in a cold hand , as it happens to be held out at a just , or at too near a distance from the fire : ) if , i say , these , and a thousand other questions of the like kind , be ask'd , the answer will be but the general one , that is already given , that such is the nature of man. for to say , that moderate motions are agreeable to the nature of the sensory they are excited in , but violent and disorderly ones , ( as j●ring sounds , and scorching heat ) do put it into too violent a motion for its texture ; will by no means satisfie . for , besides that this answer gives no account of the variety of sensations of the same kind , as of differing colours , tastes , &c. but reaches onely to pleasure and pain ; even as to these , it will reach but a very little way ; unless the givers of it can show , how an immaterial substance should be more harm'd by the brisker motion of a body , than by the more languid . and as you and your friend think , you may justly smile at the aristotelians , for imagining that they have given a tolerable account of the qualities of bodies , when they have told us , that they spring from certain substantial forms , though when they are ask'd particular questions about these incomprehensible forms , they do in effect but tell us in general , that they have such and such faculties , or effects , because nature , or the author of nature , endow'd them therewith ; so i hope you will give me leave to think , that it may keep us from boasting of the clearness and certainty of our knowledge about the operations of sensible objects , whilst , as the aristotelians cannot particularly show , how their qualities are produc'd , so we cannot particularly explicate , how they are perceiv'd ; the principal thing that we can say , being , in substance , this , that our sensations depend upon such an union or permistion of the soul and body , as we can give no example of in all nature , nor no more distinct account of , than that it pleased god so to couple them together . but i beg your pardon for having detain'd you so long upon one subject , though perhaps it will not prove time mis-spent , if it have made you take notice , that in spight of the clearness and certainty , for which your friend so much prefers physicks before theology , we are yet to seek , ( i say yet , because i know not what time may hereafter discover ) both for the definition of a corporeal substance , and a satisfactory account of the manner of sensation : though without the true notion of a body we cannot understand that object of physicks in general , and without knowing the nature of sensation , we cannot know that , from whence we derive almost all that we know of any body in particular . if after all this your friend shall say , that des-cartes's account of body , and other things in physicks , being the best that men can give , if they be not satisfactory , it must be imputed to humane nature not to the cartesian doctrine , i shall not stay to dispute how far the allegation is true ; especially since , though it be admitted , it will not prejudice my discourse . for , whatsoever the cause of the imperfection of our knowledge about physical matters be , that there is an imperfection in that knowledge is manifest ; and that ought to be enough to keep us from being puffed up by such an imperfect knowledge , and from undervaluing upon its account the study of those mysteries of divinity , which , by reason of the nobleness and remoteness of the objects , may much better than the nature of corporeal things , ( which we see , and feel , and continually converse with , ) have their obscurity attributed to the weakness of our humane understandings . and if it be a necessary imperfection of humane nature , that , whilst we remain in this mortal condition , the soul being confin'd to the dark prison of the body , is capable ( as even aristotle somewhere confesses ) but of a dim knowledge ; so much the greater value we ought to have for christian religion , since by its means ( and by no other without it ) we may attain a condition , wherein , as our nature will otherwise be highly blessed and advanced ; so our faculties will be elevated and enlarged , and probably made thereby capable of attaining degrees and kinds of knowledge , to which we are here but strangers . in favour of which i will not urge the received opinion of divines , that before the fall ( which yet is a less noble condition than is reserved for us in heaven , ) adam's knowledge was such , that he was able at first sight of them to give each of the beasts a name expressive of its nature ; because that in spight of some skill ( which my curiosity for divinity , not philosophy , gave me ) in the holy tongue , i could never find , that the hebrew names of animals , mention'd in the beginning of genesis , argued a ( much ) clearer insight into their natures , than did the names of the same or some other animals in greek , or other languages ; wherefore , ( as i said ) i will not urge adam's knowledge in paradise for that of the saints in heaven , though the notice he took of eve at his first seeing of her , ( if it were not convey'd to him by secret revelation ) may be far more probably urg'd , than his naming of the beasts : but i will rather mind you , that the proto-martyr's sight was strengthened so , as to see the heavens open'd , and jesus standing at the right hand of god ; and when the prophet had pray'd , that his servant's eyes might be open'd , he immediately saw the mountain , where they were , all cover'd with chariots and horsemen , which , though mention'd to be of fire , were altogether invisible to him before . to which , as a higher argument , i shall onely add a couple of passages of scripture , which seem to allow us even vast expectations as to the knowledge our glorifi'd nature may be advanc'd to . the one is that which st. paul says to the corinthians , for now we see through a glass darkly , but then face to face : now i know in part , but then shall i know even as also i am known . and the other , where christ's favourite-disciple tells believers , beloved , now we are the sons of god , and it doth not yet appear what we shall be ; but we know , that when he shall appear , we shall be like him : for we shall see him as he is . what has hitherto been discours'd , contains the first consideration , that i told you might be propos'd about the certainty ascrib'd to the knowledge we are said to have of natural things ; but this is not all i have to represent to you on this subject . for i consider further , that 't is not onely by the certainty we have of them , that the knowledge of things is endear'd to us , but also by the worthiness of the object , the number of those that are unacquainted with it , the remoteness of it from common apprehensions , the difficulty of acquiring it without peculiar advantages , the usefulness of it when attain'd , and other particulars , which 't is not here necessary to enumerate . i presume , you doubt not but your friend does very much prefer the knowledge he has of the mysteries of nature ( at many of which we have as yet but ingenious conjectures ) to the knowledge of one that understands the elements of arithmetick , though he be demonstratively sure of the truth of most of his rules and operations . and questionless copernicus received a much higher satisfaction in his notion about the stability of the sun , and the motion of the earth , though it were not so clear but that tycho , ricciolus , and other eminent astronomers have rejected it , than in the knowledge of divers of the theorems about the sphere , that have been demonstrated by euclid , theodosius , and other geometricians . our discovering that some comets are not , as the schools would have them , sublunary meteors , but celestial bodies , and the conjectural theory , which is all that hitherto we have been able to attain of them , do much better please both your friend , and you , and me , than the more certain knowledge we have of the time of the rising and setting of the fixed stars . and the estimates we can make , by the help of parallaxes , of the heights of those comets , and of some of the planets , though they are uncertain enough , ( as may appear by the vastly different distances that are assigned to those bodies by eminent astronomers ; ) yet these uncertain measures of such elevated and celestial lights do far more please us , than that we can by the help of a geometrical quadrant , or some such instrument , take with far greater certainty the height of a tower or a steeple . and so a mathematician , when he probably conjectures at the compass of the ter●estrial globe , and divides , though but unaccurately , its surface , first , into proportions of sea and land , and then into regions of such extents and bounds , and , in a word , skilfully plays the cosmographer ; thinks himself much more nobly and pleasantly imploy'd , than when , being reduc'd to play the surveyor , he does with far more certainty measure how many acres a field contains , and set out with what hedges and ditches it is bounded . now , that the knowledge of god , and of those mysteries of theology , that are ignor'd by far the greatest part of mankind , has more sublime and excellent objects , and is unattain'd to by much the greatest part even of learned men , and nevertheless is of unvaluable importance , and of no less advantage towards the purifying and improving of us here , and the making us perfect and happy hereafter , the past discourse has very much miscarried if it have not evinc'd . wherefore , as to be admitted into the p●ivy-council of some great monarch , and thereby be enabled to give a probable ghess at those thoughts and designs of his , that govern kingdoms , and make the fates of nations , is judged preferrable to that clearer knowledge that a notary can have of the dying thoughts and intentions of an ordinary person whose will he makes : and as the knowledge of a skilful physician , whose art is yet conjectural , is preferrable to that of a cutler that makes his dissecting knives , though this man can more certainly perform what he designs in his own profession , than the physician can in his : and ( in fine ) as the skill of a jeweller , that is conversant about diamonds , rubies , saphires , and some other sorts of small stones , which being for the most part brought us out of the indies , we must take many things about them upon report , is , because of the nobleness of the object , preferr'd to that of a mason that deals in whole quarries of common stones , and may be sure upon his own experience of divers things concerning them , which as to jewels we are allowed to know but upon tradition : so a more dimm and imperfect knowledge of god , and the mysteries of religion , may be more desirable , and upon that account more delightful , than a clearer knowledge of those inferior truths that physicks are wont to teach . i must now mention one particular more , which may well be added to those that peculiarly indear physicks to the divine that is studious of them . for , as he contemplates the works of nature not barely for themselves , but to be the better qualified and excited to admire and praise the author of nature ; so his contemplations are delightful to him , not barely as they afford a pleasing exercise to his reason , but as they procure him a more welcome approbation from his conscience , these distinct satisfactions being not at all inconsistent . and questionless , though esau did at length miss of his aim , yet , while he was hunting venison for the good old patriark that desired it of him , besides the pleasure he was us'd to take in pursuing the deer he chas'd , he took a great one in considering , that now he hunted to please his father , and in order to obtain of him an inestimable blessing . so , when david imployd his skilful hand and voice in praising god with vocal and instrumental musick , he receiv'd in one act a double satisfaction , by exercising his skill and his devotion ; and was no less pleas'd with those melodious sounds , as they were hymns , than as they were songs . and this example prompts me to add , that as the devout student of nature we were speaking of , does intentionally refer the knowledge he seeks of the creatures to the glory of the creator ; so in his discoveries , that which most contents him , is , that the wonders he observes in nature , heighten that admiration he would fain raise to a less disproportion to the wisdom of god ; and furnish him with a nobler holocaust for those sacrifices of praise he is justly ambitious to offer up to the deity . and as there is no doubt to be made , but that , when david invented ( as the scripture intimates that he did ) new instruments of musick , there was nothing in that invention that pleas'd him so much , as that they could assist him to praise god the more melodiously ; go the pious student of nature finds nothing more welcome in the discoveries he makes of her wonders , than the rises and helps they may afford him , the more worthily to celebrate and glorifie the divine attributes adumbrated in the creatures . and as a huntsman or a fowler , if he meets with some strange bird or beast , or other natural rarity , thinks himself much the more fortunate if it happen to be near the court , where he may have the king to present it to , than if he were to keep it but for himself or some of his companions ; so our devout naturalist has his discoveries of natures wonders indear'd to him , by having the deity to present them to , in the veneration they excite in the finder , and which they inable him to ingage others to joyn in . the fourth section . but i confess ( sir ) i much fear , that that which makes your friend have such detracting thoughts of theology , is a certain secret pride , grounded upon a conceit , that the attainments of natural philosophers are of so noble a kind , and argue so transcendant an excellency of parts in the attainer , that he may justly undervalue all other learning , without excepting theology it self . you will not , i suppose , expect , that a person , who has written so much in the praise of physiques , and laboured so much for a little skill in it , should now here endeavour to depretiate that so useful part of philosophy . but i do not conceive , that it will be at all injurious to it , to prefer the knowledge of supernatural , to that of meer natural things , and to think , that the truths , which god indiscriminately exposes to the whole race of mankind , and to the bad as well as to the good , are inferiour to those mysterious ones , whose disclosure he reckons among his peculiar favours , and whose contemplation employs the curiosity , and , in some points , exacts the wonder of the very angels . that i may therefore repress a little the overweening opinion your friend has of his physical attainments , give me leave to represent a few particulars conducive to that purpose . and first , as for the nobleness of the truths taught by theology and physicks , those of the former sort have manifestly the advantage , being not onely conversant about far nobler objects , but discovering things that humane reason of it self can by no means reach unto ; as has been sufficiently declared in the foregoing part of this letter . next , we may consider , that , whatever may be said to excuse pride ( if there were any ) in moscus the phoenician , who is affirmed to have first invented the atomical hypothesis , and in democritus and leucippus , ( for epicurus scarce deserves to be named with them , ) that highly advanc'd that philosophy ; and in monsieur des-cartes , who either improv'd , or at least much innovated the corpuscula●ian hypothesis : whatever ( i say ) may be alledged on the behalf of these mens pride ; i see no great reason , why it should be allowed in such as your friend ; who , though ingenious men , are neither inventors , nor eminent promoters of the philosophy they would be admir'd for , but content themselves to learn what others have taught , or at least to make some little further application of the principles that others have established , and the discoveries they have made . and whereas your friend is not a little proud of being able to confute several errours of aristotle and the antients , it were not amiss if he consider'd , that many of the chief truths that overthrow those errours , were the productions of time and chance , and not of his daring ratiocinations : for , there needs no great wit to disprove those that maintain the uninhabitableness of the torrid zone , or deny the antipodes , since navigators have found many parts of the former well peopl'd , and sailing round the earth , have found men living in countreys diametrically opposite to ours . nor will it warrant a man's pride , that he believes not the moon to be the onely planet that shines with a borrowed light , or the galaxy to be a meteor ; since that now the telescope shows us , that venus has her full and wain like the moon , and that the milky way is made up of a vast multitude of little stars , inconspicuous to the naked eye . and indeed of those other discoveries that overthrow the astronomy of the antients , and much of their philosophy about the celestial bodies , few or none have any cause to boast , but the excellent galileus , who pretends to have been the inventor of the telescope : for that instrument once discover'd ; to be able to reject the septenary number of the planets by the detection of the four satellites of jupiter , or talk of the mountains and valleys in the moon , requires not much more excellency in your friend , than it would to descry in a ship , where the naked eye could discern but the body of the vessel , ( to descry , i say ) by the help of a prospective glass , the masts , and sails , and deck , and perceive a boat tow'd at her stern : though indeed galileo himself had no great cause to boast of the invention , though we are much oblig'd to him for the improvement of the telescope , since no less a master of dioptricks than des-cartes , does acknowledge with other writers , that perspective-glasses were not first found out by mathematicians or philosophers , but casually by one metius , a dutch spectacle-maker . on which occasion i shall mind you , that to hide pride from man , divers others of the chief discoveries that have been made in physicks , have been the productions , not of philosophy , but chance , by which gunpowder , glass , and , for ought we know , the verticity of the load-stone , ( to which we owe both the indies ) came to be found in these later ages ; as ( more recently ) the milky vessels of the mesentery , the new receptacle of the chyle , and that other sort of vessels which most men call the lymphae-ducts , were lighted on but by chance , according to the ingenious confession of the discoverers themselves . we may farther consider , that those very things which are justly are alledg'd in the praise of the corpuscularian philosophy it self , ought to lessen the pride of those that but make use of it . for that hypothesis , supposing the whole universe ( the soul of man excepted ) to be but a great automaton , or self-moving engine , wherein all things are perform'd by the bare motion ( or rest ) the size , the shape , and the scituation or texture of the parts of the universal matter it consists of ; all the phaenomena result from those few principles , single or combin'd , ( as the several tunes or chimes that are rung on five bells , ) and these fertile principles being already establish'd by the inventors and promoters of the particularian hypothesis ; all that such persons as your friend , are wont farther to do , is but to investigate or guess , by what kind of motions the three or four other principles are varied . so that the world being but , as it were , a great piece of clock-work , the naturalist as such , is but a mechanitian ; however the parts of the engine , he considers , be some of them much larger , and others much minuter , than those of clocks or watches . and for an ordinary naturalist to despise those that study the mysteries of religion , as much inferiour to physical truths , is no less unreasonable , than it were for a watch-maker , because he understands his own trade , to despise privy-counsellers , who are acquainted with the secrets of monarchs , and mysteries of state ; or than it were for a ship-carpenter , because he understands more of the fabrick of the vessel , to despise the admiral , that is acquainted with the secret designs of the prince , and imploy'd about his most important affairs . that great restorer of physicks , the illustrious verulam , who has trac'd out a most useful way to make discoveries in the intellectual globe , as he calls it , confesses , that his work was ( to speak in his own terms ) partus temporis potius quám ingenii . and though i am not of his opinion , where he says in another place , that his way of philosophizing does exaequare ingenia ; yet i am apt to think , that the fertile principles of the mechanical philosophy being once setled , the methods of inquiring and experimenting being found out , and the physico-mechanical instruments of working on natures and arts productions being happily invented , the making of several lesser improvements , especially by rectifying of some almost obvious or supine errours ▪ of the schools , by the assistance of such facilitating helps , may fall to the lot of persons not endow'd with any extraordinary sagacity , or acuteness of parts . and though the investigation and clear establishment of the true principles of philosophy , and the devising the instruments of knowledge , be things that may be allowed to be the proper work of sublimer wits ; yet , if a man be furnish'd with such assistances , 't is not every discourse that he makes , or thing which he does by the help of them , that is difficult enough to raise him to that illustrious rank . and indeed , divers of the vulgar errours , as well as of scholars as other men , being mainly grounded upon the meer , and often mistaken , authority of aristotle , and perhaps some frivolous reasons of his scholastic interpreters of such precarious and ungrounded things , that to ruine them , does oftentimes require more of boldness than skill ; it may perhaps be said of your friend , in relation to his philosophical successes against such vulgar errours , as i am speaking of , what a roman said of alexander's triumph over the effeminate asiaticks , quod nihil aliud quám bene ausus sit vana contemnere . and in some cases it happens , that , when once a grand truth , or a happy way of experimenting has been found , divers phaenomena of nature , that had been left unexplain'd , or were left mis-explain'd by the schools , did , in my opinion , require a far less straining exercise of the mind to unriddle and explain them , than must have been requisite to dispel the darkness that attended divers theological truths that are now clear'd up , and perhaps than i have my self now and then imploy'd in some of those attempts , to illustrate theological matters , that you may have met in some papers that i have presum'd to write on such subjects . and indeed the improvements , that such virtuosi as your friend are wont to make of the fertile theorems and hints , that have been presented them by the founders or prime benefactors of true natural philosophy , are so poor and slender , and do so much oftner proceed from industry and chance , than they argue a transcendent sagacity , or a sublimity of reason , that , though such persons may have cause enough to be delighted with what they have done , yet they have none to be proud of it ; and their performances may deserve our thanks , and perhaps some of our praise , but reach not so high as to merit our admiration ; which is to be reserv'd for those , that have been either framers , or grand promoters , of true and comprehensive hypotheses , or ( else ) the authors of other noble and useful discoveries , many ways applicable . it will not perhaps be improper to add on this occasion , that , as our knowledge is not very deep , not reaching with any certainty to the bottom of things , nor penetrating to their intimate or innermost natures ; so its extent is not very large , not being able to give us , with any clearness and particularity , an account of the celestial and deeply subterraneal parts of the world , of which all the others make but a very small ( not to say contemptible ) portion . for , as to the very globe that we inhabit , not to mention , how many plants , animals , and minerals , we are as yet wholly ignorant of , and how many others we are but slenderly acquainted with ; i consider , that the objects about which our experiments and inquiries are conversant , do all belong to the superficial parts of the terrestrial globe , of which the earth , known to us , seems to be but as it were the crust or scurf . but what the internal part of this globe is made up of , is no less disputable than of what substance the remotest stars we can descry , consist : for even among the modern philosophers some think , the internal portion of the earth to be pure and elementary earth , which ( say they ) must be found there , or no where . others imagine it to be fiery , and the receptacle either of natural or hellish flames . others will have the body of the terrestrial globe to be a great and solid magnet . and the cartesians on the other side , ( though they all admit store of subterraneal loadstones ) teach , that the same globe was once a fix'd star , and that , though it have since degenerated into a planet , yet the internal part of it is still of the same nature that it was before ; the change it has received proceeding onely from having had its outward parts quite cover'd over with thick spots ( like those to be often observ'd about the sun , ) by whose condensation the firm earth we inhabit was form'd . and the mischief is , that each of these jarring opinions is almost as difficult to be demonstratively prov'd false as true. for , whereas to the centre of the earth there is , according to the modestest account of our late cosmographers , above three thousand and five hundred miles ; my inquiries among navigators and miners have not yet satisfi'd me , that mens curiosity has actually reached above one mile or two at most downwards , ( and that not in above three or four places , ) either into the earth or into the sea. so that as yet our experience has scarce grated any thing deep upon the husk , ( if i may so speak ) without at all reaching the kernel of the terraqueous globe . and alas ! what is this globe of ours , of which it self we know so little , in comparison of those vast and luminous globes that we call the fix'd stars , of which we know much less ? for , though former astronomers have been pleased to give us , with a seeming accurateness , their distances and bignesses , as if they had had certain ways of measuring them ; yet later and better mathematicians will ( i know ) allow me to doubt of what those have deliver'd . for since 't is confess'd , that we can observe no parallax in the fix'd stars ( nor perhaps in the highest planets , ) men must be yet to seek for a method to measure the distance of those bodies . and not onely the copernicans make it to be i know not how many hundred thousands of miles greater than the ptolomeans , and very much greater than even tycho ; but ricciolus himself , though a great anti-copernican , makes the distance of the fix'd stars vastly greater , than not onely tycho , but ( if i mis-remember not ) than some of the copernicans themselves . nor do i wonder at these so great discrepances , ( though some amount perhaps to some millions of miles , ) when i consider , that astronomers do not measure the distance of the fix'd stars by their instruments , but accommodate it to their particular hypotheses . and by this uncertainty of the remoteness of the fix'd stars you will easily gather , that we are not very sure of their bulk , no not so much as in reference to one another ; since it remains doubtful , whether the differing sizes , they appear to us to be of , proceed from a real inequality of bulk , or onely from an inequality of distance , or partly from one of those causes , and partly from the other . but 't is not my design to take notice of those things , which the famous disputes among the modern astronomers manifest to be dubious . for i consider , that there are divers things relating to the stars , which are so remote from our knowledge , that the causes of them are not so much as disputed of , or inquired into , such as may be among others , why the number of the stars is neither greater nor lesser than it is ? why so many of those celestial lights are so plac'd , as not to be visible to our naked eyes , nor even when they are help'd by ordinary telescopes ? ( which extraordinary good ones have assured me of . ) why among the familiarly visible stars , there are so many in some parts of the sky , and so few in others ? why their sizes are so differing , and yet not more differing ? why they are not more orderly plac'd , so as to make up constellations of regular or handsome figures ( of which the triangle is , perhaps , the single example ) but seem to be scatter'd in the skie as it were by chance , and have as confus'd configurations , as the drops that fall upon ones hat in a shower of rain ? to which divers other questions might be added , as about the stars , so about the interstellar part of heaven , which several of the modern epicureans would have to be empty , save where the beams of light ( and perhaps some other celestial effluvia ) pass through it ; and the cartesians on the contrary think to be full of an aethereal matter , which some , that are otherwise favourers of their philosophy , confess they are reduc'd to take up but as an hypothesis . so that our knowledge is much short of what many think , not onely if it be consider'd intensively , but extensively , ( as a schoolman would express it . ) for there being so great a disproportion between the heavens and the earth , that some moderns think the earth to be little better than a point in comparison even of the orb of the sun ; and the cartesians , with other copernicans , think the great orb it self , ( which is equal to what the ptolomeans call'd the sun's orb ) to be but a point in respect of the firmament ; and all our astronomers agree , that at least the earth is but a physical point in comparison of the starry heaven : of how little extent must our knowledge be , which leaves us ignorant of so many things , touching the vast bodies that are above us , and penetrates so little a way even into the earth that is beneath us , that it seems confin'd to but a small share of the superficial part of a physical point ! of which consideration the natural result will be , that , though what we call our knowledge , may be allowed to pass for a high gratification to our minds , it ought not to puff them up ; and what we know of the system , and the nature of things corporeal ▪ is not so perfect and satisfactory , as to justifie our despising the discoveries of spiritual things . one of the former parts of this letter may furnish me with one thing more , to evince the excellencies and prerogatives of the knowledge of the mysteries of religion ; and that one thing is such , that i hope i shall need to add nothing more , because it is not possible to add any thing higher ; and that is , that the preeminence above other knowledge , adjudg'd to that of divine truths by a judge above all exception , and above all comparison , namely , by god himself . this having been but lately shown , i shall not now repeat it , but rather apply what hath been there evinc'd , by representing , that if he , who determines in favour of divine truths , were such an one , as was less acquainted , than our over-weening naturalists with the secrets of their idoliz'd physicks ; or if he were , though an intelligent , yet ( like an angel ) a bare contemplator of what we call the works of nature , without having any interest in their productions , your friends not acquiescing in his estimate of things might have , though not a fair excuse , yet a stronger temptation . but when he , by whose direction we prefer the higher truths revealed in the scripture , before those which reason alone teaches us concerning those comparatively mean subjects , things corporeal , is the same god that not onely understands the whole universe , and all its parts , far more perfectly , than a watch-maker can understand one of his own watches , ( in which he can give an account onely of the contrivance , and not of the cause of the spring , nor the nature of the gold , steel , and other bodies his watch consists of , ) but did make both this great automaton , the world , and man in it : we have no colour to imagine , that he should either be ignorant of , or injuriously disparage , his own workmanship , or impose upon his favourite-creature , man , in directing him what sort of knowledge he ought most to covet and prize . so that since 't is he who fram'd the world , and all those things in it we most admire , that would have us prefer the knowledge he has vouchsafed us in his word , before that which he has allow'd us of his works , sure 't is very unreasonable and unkind to make the excellencies of the workmanship a disparagement to the author , and the effects of his wisdom a motive against acquiescing in the decisions of his judgment ; as if , because he is to be admir'd for his visible productions , he were not to be believ'd , when he tells us , that there are discoveries that contain truths more valuable than those which relate but to the objects , that he has expos'd to all men's eyes . the fifth section . i doubt , i should be guilty of a most important omission , if i should here forget to consider one thing , which i fear has a main stroak in the partiality your friend expresseth in his preference of physicks to theology ; and that is , that he supposes he shall by the former acquire a fame , both more certain and more durable , than can be hop'd for from the latter . and i acknowledge , not onely with readiness , but with somewhat of gratulation of the felicity of this age , that there is scarce any sort of knowledge more in request , than that which natural philosophy pretends to teach ; and that among the awaken'd and inquisitive part of mankind , as much reputation and esteem may be gain'd by an insight into the secrets of nature , as by being intrusted with those of princes , or dignifi'd with the splendid'st marks of their favour . but though i readily confess thus much , and though perhaps i may be thought to have had , i know not by what fate , as great a share of that perfum'd smoak , applause , as ( at least ) some of those , which among the writers that are now alive , your friend seems most to envy for it ; yet i shall not scruple to tell you , partly from observation of what has happen'd to others , and partly too upon some little experience of my own , that neither is it so easie as your friend seems to believe it , to get by the study of nature a sure and lasting reputation , neither ought the expectation of it , in reason , make men undervalue the study of divinity . nor would it here avail to object ( by way of prevention ) that the difficulties and impediments of acquiring and securing reputation , lie as well in the way of divines as philosophers , since this objection has been already consider'd at the beginning of this second part of our present tract . besides , that the progress of our discourse will shew , that the naturalist , aspiring to fame , is liable to some inconveniences , which are either not at all , or not near equally incident to the divine . wherefore without staying to take any further notice of this preventive allegation , i shall proceed to make good the first part of the assertion that preceded it ; which that i may the more fully do , give me leave ( after having premised , that a man must either be a writer , or forbear to print what he knows ; ) to propose to you the following considerations . and first , if your physeophilus should think to secure a great reputation , by forbearing to couch any of his thoughts or experiments in writing , he may thereby find himself not a little mistaken . for if once he have gain'd a repute ( upon what account soever ) of knowing some things that may be useful to others , or of which studious men are wont to be very desirous , he will not avoid the visits and questions of the curious . or , if he should affect a solitude , and be content to hide himself , that he may hide the things he knows ; yet he will not escape the sollicitations that will be made him by letters . and if these ways of tempting him to disclose himself , prevail not at all with him to do so , he will provoke the persons that have employ'd them ; who finding themselves disoblieg'd by being defeated of their desires , if not also their expectations , will for the most part endeavour to revenge themselves on him , by giving him the character of an uncourteous and ill-natur'd person ; and will endeavour , perhaps successfully enough , to decry his parts , by suggesting , that his affected concealments proceed but from a conscientiousness , that the things he is presum'd to possess , are but such , as , if they should begin to be known , would cease to be valu'd . you will say ( perchance , ) that so much reservedness is a fault : nor shall i dispute it with you , whether it be or not ; but , if he be open and communicative in discourse to those strangers that come to pump him , such is the disingenious temper of too too many , that he will be in great danger of having his notions or experiments arrogated by those to whom he imparts them , or at least by others , to whom those may ( though perchance designlessly ) happen to discourse of them . and then , if either physeophylus , or any of his friends that know him to be author of what is thus usurp'd , should mention him as such , the usurpers and their friends would presently become his enemies ; and , to secure their own reputation , will be sollicitous to lessen and blemish his . and if you should now tell me , that your friend might here take a middle way , as that which in most cases is thought to be the best , by discoursing at such a rate of his discoveries , as may somewhat gratifie those that have a curiosity to learn them , and yet not speak so clearly as divest himself of his propriety in them ; i should reply , that neither is this expedient a sure one , nor free from inconveniences . for most men are so self-opinionated , that they will easily believe themselves masters of things , if they do but half understand them . and however , though the persons to whom the discourse was immediately made , should not have too great an opinion of themselves , no more than too great a sagacity ; yet they may easily , by repeating what they heard and observ'd , give some more piercing wit a hint sufficient to enable him to make out the whole notion , or the discovery , which he will then without scruple , and without almost any possibility of being disprov'd , assume for his own . but if it happen , ( as it often will in extemporaneous discourse ) that a philosopher be not rightly understood ; either because he has not the leisure , no more than a design , to explain himself fully , or because the persons he converses with bring not a competent capacity and attention , he then runs a greater danger than before . for the vanity most men take in being known to have convers'd with eminent philosophers , makes them very forward to repeat what they heard such a famous wit say ; and oftentimes being secure of not being contradicted , ignorantly to misrecite it , or wittingly to wrest it in favour of the opinion they would countenance by it . so that , whereas by the formerly mention'd franckness of discourse he is onely in danger to have the truths he discover'd arrogated by others , this reservedness exposes him to have opinions and errours that he never dream'd of , father'd on him. and when a man's opinions or discoveries come once to be publickly discours'd of , without being propos'd by himself , or some friend well instructed by him , he knows not , what errours or extravagancies may be imputed to him ( and that without a moral possibility left to most men to discern them , ( by the mistake of the weak , or the disingenuity of the partial , or the artifices of the malitious . and even the greatness of a mans reputation does sometimes give such countenance to vain reports and surmises , as by degrees to shake , if not ruine , it . as we see , that fryer bacon , and trithemius , and paracelsus , who for their times were knowing as well as famous men , had such feats ascrib'd to them , as by appearing fabulous to most of the judicious , have tempted many to think , that all the great things that were said of them were so too . these are some of the inconveniences that a naturalist may be liable to , if he forbear the communicating of his thoughts and discoveries himself : but if physeophilus should , to shun these , aspire to fame by the usual way of writing books , he may indeed avoid these , but perhaps not without running into other inconveniences and hazards , very little inferiour to them . first then , we may consider , that whether a man writes in a systematical way , as they have done who have publish'd entire bodies of natural philosophy , or methodical treatises of some considerable part of it , or whether he write in a more loose and unconfin'd way , of any particular subject that belongs to physicks ; whichsoever , i say , of these two ways of writing books he shall make choice of , he will find it liable to inconvenience enough . for if he write systematically , first , he will be obliged ( that he may leave nothing necessary undeliver'd ) to say divers things that have been said ( perhaps many times ) by others already , which cannot but be unpleasant , not onely to the reader , but ( if he be ingenious ) to the writer . next , there are so many things in nature , whereof we know little or nothing , and so many more of which we do not know enough , that our systematical writer , though we should grant him to be very learned , must needs , either leave divers things that belong to his theme untreated of , or discourse of them slightly , and oftentimes ( in likelihood ) erroneously . so that in this kind of books there is always much said that the reader did know , and commonly not a little that the writer does not know . and to this i must add in the third place , that natural philosophy , being so vast and pregnant a subject , that ( especially in so inquisitive an age as this ) almost every day discovers some new thing or other about it , 't is scarce possible for a method , that is adapted but to what is already known , to continue long the most proper ; as the same clothes will not long fit a child , whose age will make him quickly out-grow them . and therefore succeeding writers will have a fair pretence to compile new systems , that may be more adequate to philosophy improv'd since the publication of the former . and though there were little of new to be added , and it were more easie to alter than to mend the method of our supposed authour ; yet novelty it self is a thing so pleasing and inviting to the generality of men , that it often recommends things that have nothing else to recommend them ; and we may apply to a great many other things , what i remember a famous courtier of my acquaintance used to say of mistresses , that another was preferable to a better , ( the better being but the same . ) but now if , declining the systematical way , one shall choose the other of writing loose tracts and discourses , he may indeed avoid some of the lately mention'd inconveniences , but will scarce avoid the being plunder'd by systematical writers : for these will be apt to cull out those things that they like best , and insert them in their methodical books , ( perhaps much curtal'd , or otherwise injur'd in the repeating , ) and will place them , not as their own authour did , where they may best confirm or adorn his discourse , and be illustrated or upheld by it ; but where it may best serve the turn of the compiler : and these methodical books promise so much more compendious a way than others to the attainment of the sciences they treat of , that though really for the most part they prove greater helps to the memory , than the understanding ; yet most readers , being , for want of judgment or of patience , of another mind , they are willing to take it for granted , that in former writers , if there have been any thing considerable , it has been all carefully extracted , as well as orderly digested by the later compilers : and though i take this to be a very erroneous and prejudicial conceit , yet it obtains so much , that as gol●smiths that onely give shape and lustre to gold are far more esteem'd , and in a better condition , than miners , who find the ore in the bowels of the earth , and with great pains and industry dig it up , and refine it into metall ; so those that with great study and toil successfully penetrate into the hidden recesses of nature , and discover latent truths , are usually less regarded or taken notice of by the generality of men , than those who by plausible methods and a neat style reduce the truths , that others have found out , into systems of a taking order and a convenient bulk . i consider in the second place , that as the method of the books one writes , so the bulk of them may prove prejudicial to the naturalist that aspires to fame : for if he write large books , 't is odds but that he will write in them many things unaccurate , if not impertinent , or that he will be oblig'd to repeat many things that others have said before ; and if he write but small tracts , as is the custome of the judiciousest authors , who have no mind to publish but what is new and considerable , as their excellency will make them to be the sooner dispers'd , so the smallness of the bulk will endanger them to be quickly lost ; as experience shows us of divers excellent little tracts , which , though publish'd not many years ago , are already out of print , ( as they speak ) and not to be met with , save by chance , in stationers shops . so that these writings ( which deserve a better fate ) come , after a while , either to be lost , ( which is the case of divers , ) or to have their memory preserv'd onely in the larger volume of some compiler , whose industry is onely preferable to his judgment ; it being observable , that ( by i know not what unlucky fate ) very few ( for i do not say , none ) that addict themselves to make collections out of others , have the judgment to cull out the choisest things in them ; and the small tracts , we are speaking of , being preserv'd but in such a quoter or abridger , will run a very great danger of being convey'd to posterity but under such a representation as it pleases the compiler . and this ( that i may proceed to my third consideration ) may make the naturalists fame very uncertain , not onely because of the want of judgment , that ( as i newly said ) is too often observable in compilers , whereby they frequently leave far better things than they take , but for the want of skill to understand the author they cite and epitomize , or candor to do him right . for sometimes mens physical opinions , and several passages of their writings , are so misrepresented by mistake or design , especially if those that recite their opinions be not of them , that men are made to teach or deliver things quite differing from their sense , and perhaps quite contrary to it ; of which , i my self have had some unwelcome experience , a learned writer pretending , i know not how often , that i asserted an opinion , about which i did expressly 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . and another noted writer having ( not out of design , but unacquaintedness with mechanicks , and the subject i writ of , ) given me commendations for having , by a new experiment , prov'd a thing , the quite contrary whereof i intended thereby to evince , and am not alone mistaken , if i did not do it . other naturalists i have met with , whose writings compilers have traduc'd out of hatred to their persons , or their religion ; as if truth could in nothing be a friend to one that is the traducers's enemy ; or as if a man that falls into an errour in religion , could not light upon a good notion in philosophy , in spite of all the truths we owe to aristotle , epicurus , and the other heathen philosophers . nay , some there are , that will set themselves to decry a man's writings , not because they are directly his enemies , but because he is esteem'd by theirs ; as you may remember an instance in a servant of yours , who had divers things written against him upon this very account . nor is it onely by the citations of profess'd adversaries or opponents , that a worthy writer's reputation may be prejudic'd , since 't is not unfrequently so by those , that mention him with an encomium , and seem dispos'd to honour him . for i have observ'd it to be the trick of certain writers , to name an author with much complement , onely for some one or few of the least considerable things they borrow of him ; by which artifice they endeavour to conceal their being plagiaries of more and better ; which yet is more excusable than the practise of some , who proceed to that pitch of disingenuity , that they will rail at an author , to whom indeed they owe too much , that they may not be thought to be beholden to him . but ( . ) i must add , that besides these dangers that a naturalists reputation with posterity may run through the ignorance or perversness of men , it is liable to divers other hazards , from the very nature both of men , of opinions , and of things . for , as men's genius's and inclinations are naturally various in reference to studies , one man passionately affecting one sort of them , and another being fond of quite differing ones ; so those inclinations are oftentimes variously and generally determin'd by external and accidental causes . as when some great monarch happens to be a great patron , or a despiser , and perhaps adversary , of this or that kind of learning : and when some one man has gain'd much applause for this or that kind of study ; imitation , or emulation oftentimes makes many others addict themselves to it . thus though rome under the consuls was inconsiderable for learning , yet the reputation of cicero , and favour of augustus , brought learning into request there ; where the small countenance it met with among most of the succeeding emperours , kept it far inferiour to what it had been among the greeks about alexander's age. and the age of the same augustus was enobled with store of poets , not onely by the countenance which he and maecenas afforded them , but probably also by the examples they gave to , and the emulation they excited in , one another . and after the decay of the roman empire , in the fourth century , natural philosophy and the mathematicks being very little valued , and less understood , by reason that mens studies were , by the genius of those ages apply'd to other subjects , every hundred years scarce produc'd one improver , ( not to say one eminent cultivator ) either of mathematicks or of physicks : by which you may see , how little certainty there is , that , because a man is skill'd in natural philosophy , and that science is now in request , his reputation shall be as great as now , when perhaps the science it self will be grown out of repute . but besides the contingencies that may happen to a naturalist's fame upon this account , that the science he cultivates , is , as well as others , subject to wanes and eclipses in the general esteem of men ; there is another uncertainty arising from the vicissitudes that are to be met with in the estimates men make of differing hypotheses , sects , and ways of philosophizing about the same science , and particularly about natural philosophy . for during those learned times , when physicks first and most flourish'd among the grecians , democritus , leucippus , epicurus , anaxagoras , plato , and almost all the naturalists that preceded aristotle , were corpuscularians , endeavouring , though not all by the same way , to give an account of the phaenomena of nature , and even of qualities themselves , by the bigness , shape , motion , &c. of corpuscles , or the minutest active parts of matter : whereas aristotle , having attempted to deduce the phaenomena from the four first qualities , the four elements , and some few other barren hypotheses , ascribing what could not be explicated by them , ( and consequently far the greatest part of natures phaenomena ) to substantial forms and occult qualities ; ( principles that are readily nam'd , but scarce so much as pretended to be understood , ) and having upon these slight and narrow principles reduc'd physicks into a kind of system , which the judicious modesty of the corpuscularians had made them backward to do ; the reputation that his great pupil alexander , as well as his learning gave him ; the easiness of the way he propos'd to the attainment of natural philosophy ; the good luck his writings had to survive those of democritus , and almost all the rest of the corpuscularians , when charles the great began to establish learning in europe : these , i say , and some other lucky accidents that concurr'd , did for about seven or eight hundred years together , make the corpuscularian philosophy not onely be justled , but even exploded out of the schools by the peripatetick ; which in our times is , by very many , upon the revival of the corpuscularian philosophy , rejected , and , by more than a few , derided as precarious , unintelligible , and useless . and to give an instance in a particular thing , ( which , though formerly named , deserves to be again mention'd to our present purpose , ) aristotle himself somewhere confesses , ( not to say brags ) that the greek philosophers , his predecessors did , unanimously teach , that the world was ( i say not created , but ) made , and yet he , almost by his single authority , and the subtile arguments ( as some have been pleased to think them , ) that he employ'd , ( though divers of them were borrow'd of ocellus lucanus , ) was able for many ages to introduce into the schools of philosophers that irreligious and ill-grounded opinion of the eternity of the world , which afterwards the christian doctrine made men begin to question , and which now both that and right reason have perswaded most men to reject . and this invites me to consider farther , that the present success of the opinions that your physeophilus befriends , ought not to make him so sure as he thinks he is , that the same opinions will be always in the same , or greater vogue , and have the same advantages , in point of general esteem that they now have , over their corrivals . for , opinions seem to have their fatal seasons and vicissitudes , as well as other things ; as may appear , not onely by the examples of it newly given , but also by the hypothesis of the earths motion , which having been in great request before pythagoras , ( who yet is commonly thought the inventor of it , ) had its reputation much increas'd by the suffrage of the famous sect of the pythagoreans , ( whom aristotle himself takes notice of as the patrons of that opinion ; ) and yet afterwards for near years it was laugh'd at , as not onely false , but ridiculous . after all which time , this so long antiquated opinion being reviv'd by copernicus , has in a little time made so great a progress among the modern astronomers and philosophers , that if it go on to prevail at the same rate , the motion of the earth will be acknowledg'd by all its mathematical inhabitants . but though it be often the fate of an oppress'd truth , to have at length a resurrection , yet 't is not always its peculiar priviledge ; for , obsolete errours are sometimes reviv'd , as well as discredited truths : so that the general disrepute of an opinion in one age will not give us an absolute security , that 't will not be in as general request in another , in which it may perhaps not onely revive , but reign . nor is it onely in the credit of mens opinions about philosophical matters , that we may observe an inconstancy and vicissitude , but in the very way and method of philosophizing ; for democritus , plato , pythagoras , and others , who were of the more sincere and ingenious cultivators of physicks among the greeks , exercis'd themselves chiefly either in making particular experiments and observations , as democritus did in his manifold dissections of animals ; or else apply'd the mathematicks to the explicating of a particular phaenomenon of nature , as may appear ( not to mention what hero teaches in his pneumaticks , ) by the accounts , democritus , plato , and others , give of fire and other elements , from the figure and motion of the corpuscles they consist of . and although this way of philosophizing were so much in request before aristotle , that ( albeit he unluckily brought in another , yet ) there are manifest and considerable footsteps of it to be met with in some of his writings , ( and particularly in his books of animals , and his mechanical questions ; ) yet the scholastick followers of aristotle did , for many ages , neglect the way of philosophizing of the antients , and ( to the great prejudice of learning ) introduc'd every where in stead of it a quite contrary way of writing . for , not onely they laid aside the mathematicks , ( of which they were for the most part very ignorant , ) but instead of giving us intelligible and explicite ( if not accurate ) accounts of particular subjects , grounded upon a distinct and heedful consideration of them , they contented themselves with hotly disputing , in general , certain unnecessary , or at least unimportant questions about the objects of physicks , about materia prima , substantial forms , privation , place , generation , corruption , and other such general things , with which when they had quite tyr'd themselves and their readers , they usually remain'd utter strangers to the particular productions of that nature , about which they had so much wrangled , and were not able to give a man so much true and useful information about particular bodies , as even the meanest mechanicks , such as mine-diggers , butchers , smiths , and even dary-maids , could do . which made their philosophy appear so imperfect and useless , not onely to the generality of men , but to the more elevated and philosophical wits , that our great verulam attempted with much skill and industry , ( and not without some indignation ) to restore the more modest and useful way practis'd by the antients , of inquiring into particular bodies , without hastening to make systems , into the request it formerly had ; wherein the admirable industry of two of our london physicians , gilbert and harvey , has not a little assisted him . and i need not tell you , that since him , des-cartes , gassendus , and others , having taken in the application of geometrical theorems , for the explication of physical problems ; he , and they , and other restorers of natural philosophy , have brought the experimental and mathematical way of inquiring into nature into at least as high and growing an esteem , as ever it possess'd when it was most in vogue among the naturalists that preceded aristotle . to the considerations i have hitherto deduc'd , which ( perhaps ) might alone suffice for my purpose , i shall yet subjoyn one that i take to be of greater weight than any of them , for the manifesting how difficult it is to be sure , that the physical opinions , which at present procure a champion or promoter of them veneration , shall be still in request . for besides that inconstant fate of applauded opinions , which may be imputed to the inconstancy of men , there is a greater danger that threatens the aspirers reputation from the very nature of things : for the most general principles of all , viz. the figure , bigness , motion , and other mechanical affections of the small parts of matter , being ( as your friend believes ) sufficiently and clearly establish'd already ; he must expect to raise his reputation from subordinate hypotheses and theories ; and in these i shall not scruple to say , that 't is extremely difficult , even for those that are more exercis'd than he , in framing them and in making of experiments to have so reaching and attentive a prospect of all things fit to be known , as not to be liable to have their doctrine made doubtful , or disprov'd by something that he did not discover , or that after-times may . this , i doubt not , but you would easily be prevail'd with to allow , if i had leisure and conveniency to transmit to you my sceptical naturalist . and without having recourse to that tract , it may possibly suffice , that we consider , that one of the conditions of a good * hypothesis is , that it fairly comport not onely with all other truths , but with all other phaenomena of nature , as well as those 't is fram'd to explicate . for this being granted , ( which cannot be deny'd , ) he that establishes a theory , which he expects shall be acquiesc'd in by all succeeding times , and make him famous in them , must not onely have a care , that none of the phaenomena of nature , that are already taken notice of , do contradict his hypothesis at the present , but that no phaenomena that may be hereafter discover'd , shall do it for the future . and i very much question , whether physiophilus do know , or , upon no greater a number and variety of experiments than most men build upon , can know , how incompleat the history of nature we yet have , is , and how difficult it is to build an accurate hypothesis upon an incompleat history of the phaenomena 't is to be fitted to ; especially considering that ( as i was saying ) many things may be discover'd in after-times by industry or chance , which are not now so much as dream'd of , and which may yet overthrow doctrines speciously enough accommodated to the observations that have been hitherto made . those antient philosophers , that thought the torrid zone to be uninhabitable , did not establish their opinion upon wild reasonings ; and as it continu'd uncontrol'd for many ages , so perhaps it would have always done , if the discoveries made by modern navigations had not manifested it to be erroneous . the solidity of the celestial orbs was , for divers centuries above years , the general opinion of astronomers and philosophers , and yet in the last age and in ours , the free trajection , that has been observ'd in the motion of some comets from one of the supposed orbs to another , and the intricate motions in the planet mars , ( observ'd by kepler and others , to be sometimes nearer , as well as sometimes remoter from the earth than is the sun ; ) these , i say , and other phenomena undiscover'd by the antients , have made even tycho , as well as most of the recent astronomers , exchange the too long receiv'd opinion of solid orbs for the more warrantable belief of a fluid aether . and though the celestial part of the world , by reason of its remoteness from us , be the most unlikely of any other to afford us the means of overthrowing old theories by new discoveries ; yet even in that we may take notice of divers instances to our present purpose , though i shall here name but this one , viz. that , after the ptolemaick number and order of the planets had past uncontradicted for very many ages ; and even the tychonians and copernicans , ( however they did by their differing hypotheses dissent from the ptolemaick system ( as to the order , ) did ( yet ) acquiesce in it as to the number of the planets ; by the happy discoveries , made by galilaeo of the satellites of jupiter , and by the excellent hugenius , of the new planet about saturn , ( which i think i had the luck to be the first that observ'd and shew'd disbelievers of it in england , ) the astronomers of all perswasions are brought to add to the old septenary number of the planets , and take in five others that their predecessors did not dream of . that the chyle prepar'd in the stomach pass'd through the mesaraick veins to the liver , and so to the heart , was for many ages the unanimous opinion , not onely of physicians , but anatomists , whose numerous diffections did not tempt them to question it ; and yet , since the casual , though lucky , discoveries made of the milky vessels in the thorax by the dextrous pecquet , those that have had with you and i the curiosity to make the requisite experiments , are generally convinc'd , that ( at least ) a good part of the chyle goes from the stomach to the heart , without passing through the mesaraick veins , or coming at all to the liver . 't were easie to multiply instances of this kind , but i rather choose to add , that 't is not onely about the qualities , and other attributes of things , but about their causes also , that new and oftentimes accidental discoveries may destroy the credit of long and generally approv'd opinions . that quick-lime exceedingly heats the water that is pour'd on to quench it , on the account of antiperistasis , has been very long and universally receiv'd by the school-philosophers , where 't is the grand and usual argument , urg'd to establish antiperistasis ; and yet i presume you have taken notice , that this proof is made wholly ineffectual in the judgment of many of the virtuosi , by some contrary experiments of mine , and particularly that of exciting in quick-lime full as great an effervescence by the affusion of hot water in stead of cold ▪ so it has been generally believ'd , that in the congelation of water , that liquor is condens'd into a narrower room ; whereas our late experiments * have satisfied most of the curious , that ice is water expanded , or ( if you please ) that ice takes up more room than the water did , whilst it remain'd unfrozen . and whereas the notion of natures abhorrence of a vacuum , has not onely ever since aristotle's time made a great noise in the schools , but seems to be confirmable by a multitude of phaenomena ; the experiments of torricellius , and some of * ours , evidencing , that the air has a great weight and a strong spring , have , i think , perswaded almost all , that have impartially consider'd them , that , whether there be or be not such a thing as they call fuga vacui , yet suction , and the ascension of water in pumps , and those other phaenomena that are generally ascrib'd to it , may be very well explicated without it , and are indeed caus'd by the weight of the atmosphere , and the elastical power of the air. and this puts me in mind to take notice , that even practical inventions , where one would think the matter of fact to be evident , may by undream'd of discoveries be brought to lose the general reputation they had for compleatness in their kind . for to endear the invention of sucking pumps and of syphons , it has been generally presum'd , that by means of either of these , water and any other liquor may , ob fugam vacui , be rais'd to what height one pleases ; and accordingly ways have been propos'd by famous authors , to convey water from one side of an high mountain to the other : whereas first the unexpected disappointments that were met with by some pump-makers , and afterwards experiments purposely made , sufficiently evince , that neither a pump nor a syphon will raise water to above foot or thereabouts , nor quicksilver to so many inches . and as to the invention of weather-glasses , which has been so much and justly applauded and us'd , as it has been generally receiv'd for the truest standard of the heat and cold of the weather ; so it seems to be liable to no suspition of deceiving us : for not onely 't is evident , that in winter , when the air is very cold , the water rises much higher than in summer and other seasons , when 't is not so ; but if you but apply your warm hand to the bubble at the top , the water will be visibly depress'd by the rarifi'd air , which upon the removal of the hand returning to its former coldness , the water will forthwith as manifestly ascend again . and yet by finding , that , as the atmosphaere has a considerable weight , so this weight is not always the same , but varies much , and that , as far as i can yet discover , uncertainly enough ; i have had the luck to satisfie many of the curious , that these open thermometers are not to be safely rely'd on , since in them the liquor is made to rise and fall , not onely , as men have hitherto suppos'd , by the cold and heat of the ambient air , but ( as i have shewn by divers new experiments ) according to the varying gravity of the atmosphaere ; which variation has not onely a sensible , but a very considerable influence upon the weather-glass . to these instances i shall annex onely one more , from which we may learn , that notwithstanding a very heedful survey of all that at present a man can take notice of , or well suspect that he ought to take into his consideration , the case may be such , that having devis'd an instrument , he may use it many years with good success ; and yet , unless he were able to live very many more , he shall not be sure to out-live the danger of finding the same instrument ( though to sense as well condition'd as ever ) fallacious : as he that first appli'd a magnetick needle to the finding of the meridian line , might very probably conclude , that his needle pointing directly n. and s. or declining from it just two or three , or some other determinate number of degrees , he had discover'd a certain and ready way , without the help of sun or stars , or astronomical instruments , to describe a meridian line , and if he liv'd but an ordinary number of years after his observation , he might probably have found his instrument not deceitful ; which yet it may now be , the magnetick needle not onely declining in many places from the true points of n. and s. but ( as later discoveries inform us ) varying in tract of time its declination in the self same place . the considerations hitherto propos'd might easily enough be encreas'd by more of the same tendency , especially if i thought fit to borrow from a discourse ( of mine ) purposely written about the partiality and uncertainty of fame ; but in stead of adding to their number , i should think my self oblieged to excuse my having already mention'd so many , and insisted so much upon them , if i did not vehemently suspect , that in your physiophilus , ( as well as in many other modern naturalists , ) scarce any thing does more contribute to an undervaluation of the study of divinity , than that being eagerly ambitious of a certain , as well as a posthume fame , he is confident that physiologie will help to it ; and therefore the design of his discourse made me think it expedient to spend some time to manifest , that 't is far less easie than he thinks , to be as sure that he shall have the praises of future ages , as that ( though he have them ) he shall not hear them . the past considerations have , i presume , convinc'd you , that 't is no such easie matter for a naturalist to acquire a great reputation and be sure it will prove a lasting one . wherefore , that i may also confirm the second part of what formerly i propos'd , i now proceed to show , that , though the case were otherwse , yet he would have no reason to slight the study of divinity . . for , in the first place , nothing hinders , but that a man who values and inquires into the mysteries of religion , may attain to an eminent degree in the knowledge of those of nature . for frequently men of great parts may successfully apply themselves to more than one study ; and few of them have their thoughts and hours so much ingross'd by that one subject or imployment , but that , if they have great inclinations as well as fitness for the study of nature , they will find time , not onely to cultivate it , but to excel in it . you need not be told , that copernicus , to whom our late philosophers owe so much , was a churchman ; that his champion lansbergius was a minister , and that gassendus himself was a doctor of divinity . among the jesuites you know , that clavius and divers others have as prosperously addicted themselves to mathematicks as divinity . and as to physicks , not onely scheiner , aquilonius , kircher , schottus , zucchius , and others , have very laudably cultivated the optical and some other parts of philosophy ; but ricciolus himself , the learned compiler of that voluminous and judicious work of the almagestum novum , wherein he has inserted divers accurate observations of his own , is not onely a divine , but a professor of divinity . and without going out of our own countrey , i could , if i durst for fear of offending the modesty of those i should name , or injuring the merit of those i should omit ; i could ( i say ) if it were not for this , among our english ecclesiasticks name you divers , who though they apply themselves so much to the study of the scripture , as to be not onely solid divines , but excellent preachers , have yet been so happily conversant with nature , that , if they had liv'd in the learned times of the greeks , they would have rivall'd , if not eclips'd , some of them , pythagoras and euclid ; others of them , anaxagoras and epicurus ; and some of them , even archimedes and democritus themselves . and certainly , provided there be curiosity and industry enough imploy'd in the study of nature , it is not necessary , that the knowledge of nature should be the ultimate end of that study ; a fondness of the object being requir'd onely in order to the engaging the mind to such a serious application , as a higher aim may sufficiently invite us to ; and will rather promote than discourage . david became no less skilful in musick , than those that were addicted to it onely to please themselves in it ; though we may reasonably suppose , that so pious an authour of psalms and instruments aspired to an excellency in that delightful science , that he might apply and prefer it to the service of the temple , and promote the celebration of god's praises with it . and as experience has manifested , that the heathen philosophers , that courted moral vertue for her self , did not raise it to that pitch , to which 't was advanc'd by the heroick practises of those true christians , that in the highest exercise of vertue had a religious aim at the pleasing and injoying of god ; so i see not , why natural knowledge must be more prosperously cultivated by those selfish naturalists , that aim but at the pleasing of themselves in the attainment of that knowledge , than those religious naturalists , who are invited to attention and industry , not onely by the pleasantness of the knowledge it self , but by a higher and more ingaging consideration ; namely , that by the discoveries they make in the book of nature , both themselves and others may be excited and qualifi'd the better to admire and praise the authour , whose goodness does so well match the wisdom they celebrate , that he declares in his word , that those that honour him , he will honour . and as a man that is not in love with a fair lady , but has onely a respect for her , may have as true and perfect , though not as discomposing an idea of her face , as the most passionate inamorato ; so i see not , why a religious and inquisitive contemplator of nature may not be able to give a good account of her , without preferring her so far to all other objects of his study , as to make her his mistress , and perhaps too his idol . ii. and now i proceed to consider in the second place , that matters of divinity may , as well as those of philosophy , afford a reputation to him that discovers , or illustrates them . for though the fundamental articles of christian religion be , as i have formerly declar'd , little less evident than important ; yet there are many other points in divinity , and passages in the scripture , which ( for reasons that i have elsewhere mention'd ) are exceeding hard to be clear'd , and do not onely pose ordinary readers , and the common sort of scholars , but will sufficiently exercise the abilities of a great wit , and give him opportunity enough to manifest that he is one. for divers of the points i speak of are much benighted upon the score of the sublimity of the things they treat of ; such as are the nature , attributes , and decrees of god , which cannot be easie to the dimm understandings of us that are but men : and many other particulars that are not abstruse in their own nature , are yet made obscure to us by our ignorance , ( or at least imperfect knowledge , ) of the disus'd languages wherein they are deliver'd , and the great remoteness of the ages when , and the countreys where , the things recorded were done or said . so that oftentimes a man may need and show as great learning and judgment to dispel the darkness , wherein time has involv'd things , as that which nature has cast on them : and in effect we see , that st. augustine , st. hierom , origen , and others of the fathers , have acquir'd no less a reputation , than empedocles , anaxagoras , or zeno ; and grotius , salmasius , mr. mede , dr. hamond , and some other critical expounders of difficult texts of scripture , have thereby got as much credit , as fracastorius by his book de sympathia & antipathia ; levinus lemnius by his de occultis rerum miraculis ; or cardanus ( and his adversary scaliger ) by what they writ de subtilitate ; or even fernelius himself by his book de abditis rerum causis . and it will contribute to the credit which theological discoveries and illustrations may procure a man , that the importance of the subjects , and the earnestness wherewith men are wont to busie themselves about them , some upon the score of piety , and others upon that of interest , some to learn truths , and others to defend what they have long or publickly taught for truth , does make greater numbers of men take notice of such matters , and concern themselves far more about them , than about almost any other things , and especially far more , than about matters purely philosophical , which but few are wont to think themselves fit to judge of , and concern'd to trouble themselves about . and accordingly we see , that the writings of socinus , calvin , bellarmine , padre paulo , arminius , &c. are more famous , and more studied , than those of telesius , campanella , severinus danus , magnenus , and divers other innovators in natural philosophy . and erastus , though a very learned physician , is much less famous for all his elaborate disputations against paracelsus , than for the little tract against particular forms of church-government . and i presume you have taken notice , as well as i , that there are scarce any five new controversies in all physicks , that are known to , and hotly contended for by so many , as are the five articles of the remonstrants . iii. my second consideration being thus dispatch'd , it remains , that i tell you in the third place , that supposing , but not granting , that to prosecute the study of divinity , one must of necessity neglect the acquist of reputation ; yet this inconvenience it self ought not to deter us from the duty it would disswade . for in all deliberations , wherein any thing is propos'd to be quitted or declin'd , to obey or please god ; me thinks , we may fitly apply that of the prophet to the jewish king , who being perswaded ( to express his concern for god's glory ) to decline the assistance of an idolatrous army of israelites , and objecting , that by complying with the advice given him , he should lose a sum of money , amounting to no less than the hire of a potent army ; receiv'd from the prophet this brisk , but rational , answer , the lord is able to give thee far more than this . the apostle paul , who had been traduc'd , revil'd , buffetted , scourg'd , imprison'd , shipwrack'd , and ston'd for his zeal to propagate the truths , whose study i plead for ; after he had once had a glimpse of that great recompense of reward that is reserved for us in heaven , scruples not to pronounce , that he finds upon casting up the account ( for he uses the arithmetical term 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ) that the sufferings of this present time are not worthy to be compared with the glory that is to be reveal'd in us . and if all that the persecuted christians of his time could suffer were not suitable ( for so i remember the same greek word to signifie elsewhere ) or proportionable to that glory ; it will sure far out-weigh what we can now forego or decline for it . the loss of an advantage , and much more the bare missing of it , being usually but a negative affliction , in comparison of the actual sufferance of evil. christ did not onely tell his disciples , that he who should give the least of his followers so much as a cup of cold water upon the score of their relation to him , should not be unrewarded ; but when the same persons asked him , what should be done to them , who had left all to follow him ; he presently allots them thrones , as much outvaluing that all they had lost , as an ordinary recompense may exceed a cup of cold water . and indeed god's goodness is so great , and his treasures so unexhausted , that as he is forward to recompence even the least services that can be done him , so he is able to give the greatest a proportionable reward . solomon had an opportunity , such as never any mortal had , ( that we know of , ) either before or since , of satisfying his desires , whether of fame , or any other thing that he could wish ; ask what i shall give thee , was the proffer made him by him , that could give all things worth receiving ; and yet the wisdom even of solomon's choice , approv'd by god himself , consisted in declining the most ambition'd things of this life , for those things that might the better qualifie him to serve and please god. and to give you an example in a greater than solomon , we may consider , that he who being in the form of god , thought it not robbery to be equal with god ; and who by leaving heaven , did , to dwell on earth , quit more than any inhabitant of the earth can to gain heaven , and deny'd more to become capable of being tempted , than he did when he was tempted with an offer of all the kingdoms of the world , and the glory of them : this saviour , i say , is said in scripture to have , for the joy that was set before him , endured the cross , and despised the shame ; as if heaven had been a sufficient recompence for even his renouncing honours , and embracing torments . he that declines the acquist of the applause of men for the contemplation of the truths of god , does but forbear to gather that whilst 't is immature , which by waiting god's time he will more seasonably gather when 't is full ripe , and wholesome , and sweet . that immarcescible crown ( as st. peter calls it ) which the gospel promises to them , who by patient continuance in well doing seek for glory and honour , will make a rich amends for the declining of a fading wreath here upon earth , where reputation is oftentimes as undeservedly acquir'd , as lost : whereas in heaven , the very having celestial honours argues a title to them . and since 't is our saviour's reasoning , that his disciples ought to rejoyce when their reputation is pursued by calumny , as well as their lives by persecution , because their reward is great in heaven , we may justly infer , that the grounded expectation of so illustrious a condition may bring us more content , even when 't is not attended with a present applause , than this applause can give those who want that comfortable expectation . so that , upon the whole matter , we have no reason to despond , or to complain of the study of theology , for but making us decline an empty and transitory fame for a solid and eternal glory . the conclusion . by this time , sir , i have said as much as i think fit ( and therefore , i hope , more than upon your single account was necessary ) to manifest , that physeophilus had no just cause to undervalue the study of divinity , nor our friend the doctor , for addicting himself to it . i hope you have not forgotten what i expressly enough declar'd at the beginning of this letter , that both your friend and you admitting the holy scriptures , i knew my self thereby to be warranted to draw proofs from their authority . and if i need not remind you of this , perhaps i need not tell you by way of apology , that i am not so unacquainted with the laws of discoursing , but that , if i had been to argue with atheists or scepticks , i should have forborn to make use of divers of the arguments i have imploy'd , as fetch'd from unconceded topicks , and substituted others for such as yet i think it very allowable for me to urge , when i deal with a person , that , as your friend does onely undervalue the study of the scriptures , not reject their authority . and if the prolixity i have been guilty of already did forbid me to increase it by apologies not absolutely necessary , i should perchance rather think my self obliged to excuse the plainness of the style of this discourse ; which both upon the subject's score , and yours , may seem to challenge a richer dress . but the matter is very serious , and you are a philosopher , and when the things we treat of are highly important , i think truths clearly made out to be the most perswasive pieces of oratory . and a discourse of this nature is more likely to prove effectual on intelligent perusers , by having the reasons it presents perspicuously propos'd , and unprejudic'dly entertain'd , than by their being pathetically urg'd , or curiously adorn'd . and i have the rather forborn expressions that might seem more proper to move than to convince ; because i foresee , i may very shortly have occasion to employ some of the former sort in another letter to a friend of yours and mine , who will , i doubt , make you a sharer in the trouble of reading it . but writing this for you and physeophilus , i was far more sollicitous to give the arguments i imploy a good temper , than a bright gloss . for even when we would excite devotion , if it be in rational men , the most effectual pieces of oratory are those , which like burning-glasses inflame by nothing but numerous and united beams of light. if this letter prove so happy as to give you any satisfaction , it will thereby bring me a great one . for prizing you as i do , i cannot but wish to see you esteem those things now , which i am confident we shall always have cause to esteem ; and then most , when the light of glory shall have made us better judges of the true worth of things . and it would extremely trouble me to see you a disesteemer of those divine things , which as long as a man undervalues , the possession of heaven it self would not make him happy . and therefore , if the blessing of him whose glory is aim'd at in it , make the success of this paper answerable to the wishes , the importance of the subject , will make the service done you by it suitable to the desires of , sir , your most faithful , most affectionate , and most humble servant . finis . errata . in the introduction , p. l. . point thus ; else ; our . p. . l. . r. corpuscularian . p. . l. . r. theology for philosophy . p. . l. . r. yet many of . ibid. l. . r. else do but. p. . l. . point thus , predecessors , did unanimously teach . about the excellency and grounds of the mechanical hypothesis , some considerations , occasionally propos'd to a friend . by t. h. r. b. e. fellow of the royal society . london , printed by t. n. for henry herringman , at the anchor in the lower walk of the new exchange . . the publisher's advertisement . the following paper having been but occasionally and hastily pen'd , long after what the author had written ( by way of dialogue ) about the requisites of a good hypothesis , it was intended , that if it came forth at all , it should do so as an appendix to that discourse ; because though one part of it does little more than name some of the heads treated of in the dialogue , yet , according to the exigency of the occasion , the other part contains several things , either pretermitted , or but more lightly touched on in the discourse . but , although the author's design were to reserve these thoughts , as a kind of paralipomena to his dialogue ; yet , since he is not willing to let that , at least quickly , come abroad , and these are fallen into my hands ; i will make bold , with his good leave , to annex them to the fore-going treatise , not onely to compleat the bulk of the book , but because o● some affinity between them , since both aim at manifesting the excellency of the studies they would recommend . and perhaps 't will not be unwelcome to some of the curious to find , that our noble author in the same book , wherein he prefers the study of divine things to that of natural ones , does himself prefer the mechanical principles before all other hypotheses about natural things ; they being in their own nature so accommodate to make considering men understand , rather than dispute of , the effects of nature . of the excellency and grounds of the corpuscular or mechanical philosophy . the importance of the question , you propose , would oblige me to refer you to the dialogue about a good hypothesis , and some other papers of that kind , where you may find my thoughts about the advantages of the mechanical hypothesis somewhat amply set down , and discours'd of . but , since your desires confine me to deliver in few words , not what i believe resolvedly , but what i think may be probably said for the preference or the preeminence of the corpuscular philosophy above aristotles , or that of the chymists , you must be content to receive from me , without any preamble , or exact method , or ample discourses , or any other thing that may cost many words , a succinct mention of some of the chief advantages of the hypothesis we incline to . and i the rather comply , on this occasion , with your curiosity , because i have often observ'd you to be allarm'd and disquieted , when you hear of any book that pretends to uphold , or repair the decaying philosophy of the schools , or some bold chymist , that arrogates to those of his sect the title of philosophers , and pretends to build wholly upon experience , to which he would have all other naturalists thought strangers . that therefore you may not be so tempted to despond , by the confidence or reputation of those writers , that do some of them applaud , and others censure , what , i fear , they do not understand , ( as when the peripateticks cry up , substantial forms , and the chymists , mechanical explications ) of nature's phaenomena , i will propose some considerations , that , i hope , will not onely keep you kind to the philosophy you have embrac'd , but perhaps , ( by some considerations which you have not yet met with , ) make you think it probable , that the new attempts you hear of from time to time , will not overthrow the corpuscularian philosophy , but either be foiled by it , or found reconcilable to it . but when i speak of the corpuscular or mechanical philosophy , i am far from meaning with the epicureans , that atoms , meeting together by chance in an infinite vacuum , are able of themselves to produce the world , and all its phaenomena ; nor with some modern philosophers , that , supposing god to have put into the whole mass of matter such an invariable quantity of motion , he needed do no more to make the world , the material parts being able by their own unguided motions , to cast themselves into such a system ( as we call by that name ) ; but i plead onely for such a philosophy , as reaches but to things purely corporeal , and distinguishing between the first original of things , and the subsequent course of nature , teaches , concerning the former , not onely that god gave motion to matter , but that in the beginning he so guided the various motions of the parts of it , as to contrive them into the world he design'd they should compose , ( furnish'd with the seminal principles and structures or models of living creatures , ) and establish'd those rules of motion , and that order amongst things corporeal , which we are wont to call the laws of nature . and having told this as to the former , it may be allowed as to the latter to teach , that the universe being once fram'd by god , and the laws of motion being setled and all upheld by his incessant concourse and general providence ; the phaenomena of the world thus constituted , are physically produc'd by the mechanical affections of the parts of matter , and what they operate upon one another according to me●hanical laws . and now having shewn what kind of corpuscular philosophy 't is that i speak of i p●oceed to the particulars that i thought the most proper to recommend it . i. the first thing that i shall mention to this purpose , is the intelligibleness or clearness of mechanical principles and explications . i need not tell you , that among the peripateticks , the disputes are many and intricate about matter , privation , substantial forms , and their eduction , &c. and the chymists are sufficiently puzled , ( as i have elsewhere shewn , ) to give such definitions and accounts of their hypostatical principles , as are reconcileable to one another , and even to some obvious phaenomena . and much more dark and intricate are their doctrines about the archeus , astral beings , gas , blass , and other odd notions , which perhaps have in part occasion'd the darkness and ambiguity of their expressions , that could not be very clear , when their conceptions were far from being so . and if the principles of the aristotelians and spagyrists are thus obscure , 't is not to be expected , the explications that are made by the help onely of such principles should be clear . and indeed many of them are either so general and slight , or otherwise so unsatisfactory , that granting their principles , 't is very hard to understand or admit their applications of them to particular phaenomena . and even in some of the more ingenious and subtle of the peripatetick discourses upon their superficial and narrow theories , me thinks , the authors have better plaid the part of painters than philosophers , and have onely had the skill , like drawers of landskips , to make men fancy , they see castles and towns , and other structures that appear solid and magnificent , and to reach to a large extent , when the whole piece is superficial , and made up of colours and art , and compris'd within a frame perhaps scarce a yard long . but to come now to the corpuscular philosophy , men do so easily understand one anothers meaning , when they talk of local motion , rest , bigness , shape , order , situation , and contexture of material substances ; and these principles do afford such clear accounts of those things , that are rightly deduc'd from them onely , that even those peripateticks or chymists , that maintain other principles , acquiesce in the explications made by these , when they can be had , and seek not any further , though perhaps the effect be so admirable , as would make it pass for that of a hidden form , or occult quality . those very aristotelians , that believe the celestial bodies to be mov'd by intelligences , have no recourse to any peculiar agency of theirs to account for eclipses . and we laugh at those east-indians , that , to this day , go out in multitudes , with some instruments that may relieve the distressed luminary , whose loss of light they fancy to proceed from some fainting fit , out of which it must be rouz'd . for no intelligent man , whether chymist or peripatetic , flies to his peculiar principles , after he is informed , that the moon is eclipsed by the interposition of the earth betwixt her and it , and the sun by that of the moon betwixt him and the earth . and when we see the image of a man cast into the air by a concave spherical looking-glass , though most men are amaz'd at it , and some suspect it to be no less than an effect of witchcraft , yet he that is skill'd enough in catoptricks , will , without consulting aristotle , or paracelsus , or flying to hypostatical principles and substantial forms , be satisfied , that the phaenomenon is produc'd by the beams of light reflected , and thereby made convergent according to optical , and consequently mathematical laws . but i must not now repeat what i elsewhere say , to shew , that the corpuscular principles have been declin'd by philosophers of different sects , not because they think not our explications clear , if not much more so , than their own ; but because they imagine , that the applications of them can be made but to few things , and consequently are insufficient . ii. in the next place i observe , that there cannot be fewer principles than the two grand ones of mechanical philosophy , matter and motion . for , matter alone , unless it be moved , is altogether unactive ; and whilst all the parts of a body continue in one state without any motion at all , that body will not exercise any action , nor suffer any alteration it self , though it may perhaps modifie the action of other bodies that move against it . iii. nor can we conceive any principles more primary , than matter and motion . for , either both of them were immediately created by god , or , ( to add that for their sakes that would have matter to be unproduc'd , ) if matter be eternal , motion must either be produc'd by some immaterial supernatural agent , or it must immediately flow by way of emanation from the nature of the matter it appertains to . iv. neither can there be any physical principles more simple than matter and motion ; neither of them being resoluble into any things , whereof it may be truly , or so much as tolerably , said to be compounded . v. the next thing i shall name to recommend the corpuscular principle , is their great comprehensiveness . i consider then , that the genuine and necessary effect of the sufficiently strong motion of one part of matter against another , is , either to drive it on in its intire bulk , or else to break or divide it into particles of determinate motion , figure , size , posture , rest , order , or texture . the two first of these , for instance , are each of them capable of numerous varieties . for the figure of a portion of matter may either be one of the five regular figures treated of by geometricians , or some determinate species of solid figures , as that of a cone , cylinder , &c. or irregular , though not perhaps anonymous , as the grains of sand , hoops , feathers , branches , forks , files , &c. and as the figure , so the motion of one of these particles may be exceedingly diversified , not onely by the determination to this or that part of the world , but by several other things , as particularly by the almost infinitely varying degrees of celerity , by the manner of its progression with , or without , rotation , and other modifying circumstances ; and more yet by the line wherein it moves , as ( besides streight ) circular , elliptical , parabolical , hyperbolical , spiral , and i know not how many others . for , as later geometricians have shewn , that those crooked lines may be compounded of several motions , ( that is , trac'd by a body whose motion is mixt of , and results from , two or more simpler motions , ) so how many more curves may , or rather may not be made by new compositions and decompositions of motion , is no easie task to determine . now , since a single particle of matter , by vertue of two onely of the mechanical affections , that belong to it , be diversifiable so many ways ; how vast a number of variations may we suppose capable of being produc'd by the compositions and decompositions of myriads of single invisible corpuscles , that may be contained and contex'd in one small body , and each of them be imbued with more than two or three of the fertile catholick principles above mention'd ? especially since the aggregate of those corpuscles may be farther diversifi'd by the texture resulting from their convention into a body , which , as so made up , has its own bigness , and shape , and pores , ( perhaps very many , and various ) and has also many capacities of acting and suffering upon the score of the place it holds among other bodies in a world constituted as ours is : so that , when i consider the almost innumerable diversifications , that compositions and decompositions may make of a small number , not perhaps exceeding twenty of distinct things , i am apt to look upon those , who think the mechanical principles may serve indeed to give an account of the phaenomena of this or that particular part of natural philosophy , as staticks , hydrostaticks , the theory of the planetary motions , &c. but can never be applied to all the phaenomena of things corporeal ; i am apt , i say , to look upon those , otherwise learned , men , as i would do upon him , that should affirm , that by putting together the letters of the alphabet , one may indeed make up all the words to be found in one book , as in euclid , or virgil ; or in one language , as latine , or english ; but that they can by no means suffice to supply words to all the books of a great library , much less to all the languages in the world . and whereas there is another sort of philosophers , that , observing the great efficacy of the bigness , and shape , and situation , and motion , and connexion in engines , are willing to allow , that those mechanical principles may have a great stroke in the operations of bodies of a sensible bulk , and manifest mechanism , and therefore may be usefully imploy'd in accounting for the effects and phaenomena of such bodies , who yet will not admit , that these principles can be apply'd to the hidden transactions that pass among the minute particles of bodies ; and therefore think it necessary to refer these to what they call nature , substantial forms , real qualities ▪ and the like un-mechanical principles and agents . but this is not necessary ; for , both the mechanical affections of matter are to be found , and the laws of motion take place , not onely in the great masses , and the middle-siz'd lumps , but in the smallest fragments of matter ; and a lesser portion of it , being as well a body as a greater , must , as necessarily as it , have its determinate bulk and figure : and he that looks upon sand in a good microscope , will easily perceive , that each minute grain of it has as well it s own size and shape , as a rock or mountain . and when we let fall a great stone and a pibble from the top of a high building , we find not but that the latter as well as the former moves conformably to the laws of acceleration in heavy bodies descending . and the rules of motion are observ'd , not onely in canon bullets , but in small shot ; and the one strikes down a bird according to the same laws , that the other batters down a wall. and though nature ( or rather its divine author ) be wont to work with much finer materials , and employ more curious contrivances than art , ( whence the structure even of the rarest watch is incomparably inferiour to that of a humane body ; ) yet an artist himself , according to the quantity of the matter he imploys , the exigency of the design he undertakes , and the bigness and shape of the instruments he makes use of , is able to make pieces of work of the same nature or kind of extremely differing bulk , where yet the like , though not equal , art and contrivance , and oftentimes motion too , may be observ'd : as a smith , who with a hammer , and other large instruments , can , out of masses of iron , forge great bars or wedges , and make those strong and heavy chains that were imploy'd to load malefactors , and even to secure streets and gates , may , with lesser instruments , make smaller nails and filings , almost as minute as dust ; and may yet , with finer tools , make links of a strange slenderness and lightness , insomuch that good authors tell us of a chain of divers links that was fastned to a flea , and could be mov'd by it ; and , if i mis-remember not , i saw something like this , besides other instances that i beheld with pleasure of the littleness that art can give to such pieces of work , as are usually made of a considerable bigness . and therefore to say , that , though in natural bodies , whose bulk is manifest and their structure visible , the mechanical principles may be usefully admitted , that are not to be extended to such portions of matter , whose parts and texture are invisible ; may perhaps look to some , as if a man should allow , that the laws of mechanism may take place in a town-clock ; but cannot in a pocket-watch ; or ( to give you an instance , mixt of natural and artificial , ) as if , because the terraqueous globe is a vast magnetical body of seven or eight thousand miles in diameter , one should affirm , that magnetical laws are not to be expected to be of force in a spherical piece of loadstone that is not perhaps an inch long : and yet experience shews us , that notwithstanding the inestimable disproportion betwixt these two globes , the terrella , as well as the earth , hath its poles , aequator , and meridians , and in divers other magnetical properties , emulates the terrestrial globe . they that , to solve the phaenomena of nature , have recourse to agents which , though they involve no self-repugnancy in their very notions , as many of the judicious think substantial forms and real qualities to do ; yet are such that we conceive not , how they operate to bring effects to pass : these , i say , when they tell us of such indeterminate agents , as the soul of the world , the universal spirit , the plastic power , and the like ; though they may in certain cases tell us some things , yet they tell us nothing that will satisfie the curiosity of an inquisitive person , who seeks not so much to know , what is the general agent , that produces a phenomenon , as , by what means , and after what manner , the phenomenon is produc'd . the famous senner●us , and some other learned physicians , tell us of diseases which proceed from incantation ; but sure 't is but a very slight account , that a sober physician , that comes to visit a patient reported to be bewitch'd , receives of the strange symptoms he meets with , and would have an account of , if he be coldly answer'd , that 't is a witch or the devil that produces them ; and he will never sit down with so short an account , if he can by any means reduce those extravagant symptoms to any more known and stated diseases , as epilepsies , convulsions , hysterical fits , &c. and , if he can not , he will confess his knowledge of this distemper to come far short of what might be expected and attain'd in other diseases , wherein he thinks himself bound to search into the nature of the morbific matter , and will not be satisfi'd till he can , probably at least , deduce from that , and the structure of an humane body , and other concurring physical causes , the phaenomena of the malady . and it would be but little satisfaction to one , that desires to understand the causes of what occurrs to observation in a watch , and how it comes to point at , and strike , the hours , to be told , that 't was such a watch-maker that so contriv'd it : or to him that would know the true cause of an eccho , to be answer'd , that 't is a man , a vault , or a wood that makes it . and now at length i come to consider that which i observe the most to alienate other sects from the mechanical philosophy ; namely , that they think it pretends to have principles so universal and so mathematical , that no other physical hypothesis can comport with it , or be tolerated by it . but this i look upon as an easie indeed , but an important , mistake ; because by this very thing , that the mechanical principles are so universal , and therefore applicable to so many things , they are rather fitted to include , than necessitated to exclude , any other hypothesis that is founded in nature , as far as it is so . and such hypotheses , if prudently consider'd by a skilful and moderate person , who is rather dispos'd to unite sects than multiply them , will be found , as far as they have truth in them , to be either legitimately , ( though perhaps not immediately , ) deducible from the mechanical principles , or fairly reconcilable to them . for , such hypotheses will probably attempt to account for the phaenomena of nature , either by the help of a determinate number of material ingredients , such as the tria prima of the chymists , by participation whereof other bodies obtain their qualities ; or else by introducing some general agents , as the platonic soul of the world , or the universal spirit , asserted by some spagyrists ; or by both these ways together . now to dispatch first those , that i named in the second place ; i consider , that the chief thing , that inquisitive naturalists should look after in the explicating of difficult phaenomena , is not so much what the agent is or does , as , what changes are made in the patient , to bring it to exhibit the phaenomena that are propos'd ; and by what means , and after what manner , those changes are effected . so that the mechanical philosopher being satisfied , that one part of matter can act upon another but by vertue of local motion , or the effects and consequences of local motion , he considers , that as , if the propos'd agent be not intelligible and physical , it can never physically explain the phaenomena ; so , if it be intelligible and physical , 't will be reducible to matter , and some or other of those onely catholick affections of matter , already often mentioned . and , the indefinite divisibility of matter , the wonderful efficacy of motion , and the almost infinite variety of coalitions and structures , that may be made of minute and insensible corpuscles , being duly weighed , i see not why a philosopher should think it impossible , to make out by their help the mechanical possibility of any corporeal agent , how subtil , or diffus'd , or active soever it be , that can be solidly proved to be really existent in nature , by what name soever it be call'd or disguis'd . and though the cartesians be mechanical philosophers , yet , according to them , their materia subtilis , which the very name declares to be a corporeal substance , is , for ought i know , little ( if it be at all ) less diffus'd through the universe , or less active in it than the universal spirit of some spagyrists , not to say , the anima mundi of the platonists . but this upon the by ; after which i proceed , and shall venture to add , that whatever be the physical agent , whether it be inanimate or living , purely corporeal , or united to an intellectual substance , the above mention'd changes , that are wrought in the body that is made to exhibit the phaenomena , may be effected by the same or the like means , or after the same or the like manner ; as , for instance , if corn be reduc'd to meal , the materials and shape of the milstones , and their peculiar motion and adaptation , will be much of the same kind , and ( though they should not , yet ) to be sure the grains of corn will suffer a various contrition and comminution in their passage to the form of meal ; whether the corn be ground by a water-mill , or a wind-mill , or a horse-mill , or a hand-mill ; that is , by a mill whose stones are turned by inanimate , by brute , or by rational , agents . and , if an angel himself should work a real change in the nature of a body , 't is scarce conceivable to us men , how he could do it without the assistance of local motion ; since , if nothing were displac'd or otherwise mov'd than before , ( the like hapning also to all external bodies to which it related , ) 't is hardly conceivable , how it should be in it self other , than just what it was before . but to come now to the other sort of hypotheses formerly mention'd ; if the chymists , or others that would deduce a compleat natural philosophy from salt , sulphur , and mercury , or any other set number of ingredients of things , would well consider what they undertake , they might easily discover , that the material parts of bodies , as such , can reach but to a small part of the phaenomena of nature , whilst these ingredients are consider'd but as quiescent things , and therefore they would find themselves necessitated to suppose them to be active ; and that things purely corporeal cannot be but by means of local motion , and the effects that may result from that , accompanying variously shap'd , siz'd , and aggregated parts of matter : so that the chymists and other materialists , ( if i may so call them , ) must ( as indeed they are wont to do ) leave the greatest part of the phaenomena of the universe unexplicated by the help of the ingredients , ( be they fewer or more than three , ) of bodies , without taking in the mechanical and more comprehensive affections of matter , especially local motion . i willingly grant , that salt , sulphur , and mercury , or some substances analogous to them , are to be obtain'd by the action of the fire , from a very great many dissipable bodies here below ; nor would i deny , that , in explicating divers of the phaenomena of such bodies , it may be of use to a skilful naturalist to know and consider , that this or that ingredient , as sulphur , for instance , does abound in the body propos'd , whence it may be probably argu'd , that the qualities , that usually accompany that principle when predominant , may be also , upon its score , found in the body that so plentifully partakes of it . but not to mention , what i have elsewhere shown , that there are many phaenomena , to whose explication this knowledge will contribute very little or nothing at all ; i shall onely he●e observe , that , though chymical explications be sometimes the most obvious and ready , yet they are not the most fundamental and satisfactory : for , the chymical ingredient it self , whether sulphur or any other , must owe its nature and other qualities to the union of insensible particles in a convenient size , shape , motion or rest , and contexture ; all which are but mechanical affections of convening corpuscles . and this may be illustrated by what happens in artificial fire-works . for , though in most of those many differing sorts that are made either for the use of war , or for recreation , gunpowder be a main ingredient , and divers of the phaenomena may be deriv'd from the greater or lesser measure , wherein the compositions partake of it ; yet , besides that there may be fire-works made without gun-powder , ( as appears by those made of old by the greeks and romans , ) gun-powder it self owes its aptness to be fir'd and exploded to the mechanical contexture of more simple portions of matter , nitre , charcoal , and sulphur ; and sulphur it self , though it be by many chymists mistaken for an hypostatical principle , owes its inflammability to the convention of yet more simple and primary corpuscles ; since chymists confess , that it has an inflammable ingredient , and experience shews , that it very much abounds with an acid and uninflammable salt , and is not quite devoide of terrestreity . i know , it may be here alledg'd , that the productions of chymical analyses are simple bodies , and upon that account irresoluble . but , that divers substances , which chymists are pleased to call the salts , or sulphurs , or mercuries of the bodies that afforded them , are not simple and homogeneous , has elsewhere been sufficiently proved ; nor is their not being easily dissipable or resoluble a clear proof of their not being made up of more primitive portions of matter . for , compounded and even decompounded bodies , may be as difficultly resoluble , as most of those that chymists obtain by what they call their analysis by the fire ; witness common green glass , which is far more durable and irresoluble than many of those that pass for hypostatical substances . and we see , that some amels will be several times even vitrified in the fire , without losing their nature , or oftentimes so much as their colour ; and yet amel is manifestly not onely a compounded , but a decompounded body , consisting of salt and powder of pebbles or sand , and calcin'd tinn , and , if the amel be not white , usually of some tinging metall or mineral . but how indestructible soever the chymical principles be suppos'd , divers of the operations ascrib'd to them will never be well made out , without the help of local motion , ( and that diversified too ; ) without which , we can little better give an account of the phaenomena of many bodies , by knowing what ingredients compose them , than we can explain the operations of a watch , by knowing of how many and of what metalls the balance , the wheels , the chain , and other parts , are made ; or than we can derive the operations of a wind-mill from the bare knowledge , that 't is made up of wood , and stone ; and canvas , and iron . and here let me add , that 't would not at all overthrow the corpuscularian hypothesis , though either by more exquisite purifications , or by some other operations than the usual analysis of the fire , it should be made appear , that the material principles or elements of mixt bodies should not be the tria prima of the vulgar chymists , but either substances of another nature , or else fewer , or more in number ; as would be , if that were true , which some spagyrists affirm , ( but i could never find , ) that from all sorts of mixt bodies , five , and but five , differing similar substances can be separated : or , as if it were true , that the helmontians had such a resolving menstruum as the alkahest of their master , by which he affirms , that he could reduce stones into salt of the same weight with the mineral , and bring both that salt and all other kind of mixt and tangible bodies into insipid water . for , what ever be the numnumber or qualities of the chymical principles , if they be really existent in nature , it may very possibly be shewn , that they may be made up of insensible corpuscles of determinate bulks and shapes ; and by the various coalitions and contextures of such corpuscles , not onely three or five , but many more material ingredients , may be compos'd or made to result : but , though the alkahestical reductions newly mention'd should be admitted , yet the mechanical principles might well be accommodated , even to them . for , the solidity , taste , &c. of salt , may be fairly accounted for , by the stifness , sharpness , and other mechanical affections of the minute particles , whereof salts consist ; and if , by a farther action of the alkahest , the salt or any other solid body , be reduc'd into insipid water , this also may be explicated by the same principles , supposing a further comminution of the parts , and such an attrition , as wears off the edges and points that inabled them to strike briskly the organ of taste : for , as to fluidity and firmness , those mainly depend upon two of our grand principles , motion and rest . and i have else-where shewn , by several proofs , that the agitation or rest , and the looser contact , or closer cohaesion , of the particles , is able to make the same portion of matter , at one time a firm , and at another time , a fluid body . so that , though the further sagacity and industry of chymists ( which i would by no means discourage ) should be able to obtain from mixt bodies homogeneous substances differing in number , or nature , or both , from their vulgar salt , sulphur , and mercury ; yet the corpuscular philosophy is so general and fertile , as to be fairly reconcilable to such a discovery ; and also so useful , that these new material principles will , as well as the old tria prima , stand in need of the more catholick principles of the corpuscularians , especially local motion . and indeed , what ever elements or ingredients men have ( that i know of ) pitched upon , yet if they take not in the mechanical affections of matter , their principles have been so deficient , that i have usually observ'd , that the materialists , without at all excepting the chymists , do not onely , as i was saying , leave many things unexplain●d , to which their narrow principles will not extend ; but , even in the particulars they presume to give an account of , they either content themselves to assign such common and indefinite causes , as are too general to signifie much towards an inquisitive mans satisfaction ; or if they venture to give particular causes , they assign precarious or false ones , and liable to be easily disproved by circumstances , or instances , whereto their doctrine will not agree , as i have often elsewhere had occasion to shew . and yet the chymists need not be frighted from acknowledging the prerogative of the mechanical philosophy , since that may be reconcileable with the truth of their own principles , as far as these agree with the phaenomena they are apply'd to . for these more confind hypotheses may be subordinated to those more general and fertile principles , and there can be no ingredient assign'd , that has a real existence in nature , that may not be deriv'd either immediately , or by a row of decompositions , from the universal matter , modifi'd by its mechanical affections ▪ for , if with the same bricks , diversly put together and rang'd , several walls , houses , furnaces , and other structures , as vaults , bridges , pyramids , &c. may be built , meerely by a various contrivement of parts of the same kind ; how much more may great variety of ingredients be produc'd by , or , according to the institution of nature , result from , the various coalitions and contextures of corpuscles , that need not be suppos'd , like bricks , all of the same , or near the same , size and shape , but may have amongst them , both of the one and the other , as great a variety as need be wish'd for , and indeed a greater than can easily be so much as imagin'd . and the primary and minute concretions that belong to these ingredients , may , without opposition from the mechanical philosophy , be suppos'd to have their particles so minute and strongly coherent , that nature of her self does scarce ever tear them asunder ; as we see , that mercury and gold may be successively made to put on a multitude of disguises , and yet so retain their nature , as to be reducible to their pristine forms . and you know , i lately told you , that common glass and good amels , though both of them but factitious bodies , and not onely mix'd , but decompounded concretions , have yet their component parts so strictly united by the skill of illiterate tradesmen , as to maintain their union in the vitrifying violence of the fire . nor do we find , that common glass will be wrought upon by aqua fortis , or aqua regis , though the former of them will dissolve mercury , and the later gold. from the fore-going discourse it may ( probably at least ) result , that if , besides rational souls , there are any immaterial substances ( such as the heavenly intelligences , and the substantial forms of the aristotelians ) that regularly are to be numbred among natural agents , their way of working being unknown to us , they can but help to constitute and effect things , but will very little help us to conceive how things are effected ; so that , by what ever principles natural things be constituted , 't is by the mechanical principles that their phaenomena must be clearly explicated . as for instance , though we should grant the aristotelians , that the planets are made of a quintessential matter , and moved by angels , or immaterial intelligences ; yet , to explain the stations , progressions , and retrogradations , and other phaenomena of the planets , we must have recourse either to eccentricks , epicycles , &c. or to motions made in elliptical or other peculiar lines ; and , in a word , to theories , wherein the motion , and figure , scituation , and other mathematical or mechanical affections of bodies are mainly employ'd . but if the principles propos'd be corporeal things , they will be then fairly reducible , or reconcilable , to the mechanical principles ; these being so general and pregnant , that , among things corporeal , there is nothing real , ( and i meddle not with chymerical beings , such as some of paracelsus's , ) that may not be deriv'd from , or be brought to , a subordination to such comprehensive principles . and when the chymists shall shew , that mix'd bodies owe their qualities to the predominancy of this or that of their three grand ingredients , the corpuscularians will shew , that the very qualities of this or that ingredient flow from its peculiar texture , and the mechanical affections of the corpuscles 't is made up of . and to affirm , that , because the furnaces of chymists afford a great number of uncommon productions and phaenomena , there are bodies or operations amongst things purely corporeal , that cannot be deriv'd from , or reconcil'd to , the comprehensive and pregnant principles of the mechanical philosophy , is , as if , because there are a great number and variety of anthems , hymns , pavins , threnodies , courants , gavots , branles , sarabands , jigs , and other ( grave and sprightly ) tunes to be met with in the books and practises of musitians , one should maintain , that there are in them a great many tunes , or at least notes , that have no dependence on the scale of music ; or , as if , because , besides rhombusses , rhomboids , trapeziums , squares , pentagons , chiliagons , myriagons , and innumerable other polygons , regular and irregular , one should presume to affirm , that there are among them some rectilinear figures , that are not reducible to triangles , or have affections that will overthrow what euclid has taught of triangles and polygons . to what has been said , i shall add but one thing more ; that , as , according to what i formerly intimated , mechanical principles and explications are for their clearness preferr'd , even by materialists themselves , to others in the cases where they can be had ; so , the sagacity and industry of modern naturalists and mathematicians , having happily apply'd them to seueral of those difficult phaenomena , ( in hydrostaticks , the practical part of opticks , gunnery , &c. ) that before were , or might be referr'd to 〈◊〉 qualities , 't is probable , that , when this philosophy is deeplier searched into , and farther improv'd , it will be found applicable to the solution of more and more of the phaenomena of nature . and on this occasion let me observe , that 't is not always necessary , though it be always desirable , that he that propounds an hypothesis in astronomy , chymistry , anatomy , or other part of physicks , be able , à priori , to prove his hypothesis to be true , or demonstratively to shew , that the other hypotheses propos'd about the same subject must be false . for as , if i mistake not , plato said , that the world was god's epistle written to mankind , & might have added , consonantly to another saying of his , 't was written in mathematical letters : so , in the physical explications of the parts and system of the world , me thinks , there is somewhat like what happens , when men conjecturally frame several keys to enable us to understand a letter written in cyphers . for , though one man by his sagacity have found out the right key , it will be very difficult for him , either to prove otherwise than by trial , that this or that word is not such as 't is ghess'd to be by others according to their keys ; or to evince , à priori , that theirs are to be rejected , and his to be preferr'd ; yet , if due trial being made , the key he proposes , shall be found so agreeable to the characters of the letter , as to enable one to understand them , and make a coherent sense of them , its suitableness to what it should decipher , is , without either confutations , or extraneous positive proofs , sufficient to make it be accepted as the right key of that cypher . and so , in physical hypotheses , there are some , that , without noise , or falling foul upon others , peaceably obtain discerning mens approbation onely by their fitness to solve the phaenomena , for which they were devis'd , without crossing any known observation or law of nature . and therefore , if the mechanical philosophy go on to explicate things corporeal at the rate it has of late years proceeded at , 't is scarce to be doubted , but that in time unprejudic'd persons will think it sufficiently recommended by its consistency with it self , and its applicableness to so many phenomena of nature . a recapitulation . perceiving , upon a review , of the foregoing paper , that the difficulty and importance of the subject , has seduc'd me to spend many more words about it that i at first design'd ▪ t will not now be amiss to give you this short summary of what came into my mind to recommend to you the mechanical phelosophy , and obviate your fears of seeing it supplanted ; having first premis'd once for all , that presupposing the creation and general providence of god , i pretend to treat but of things corporeal , and do abstract in this paper from immaterial beings , ( which otherwise i very willingly admit , ) and all agents and operations miraculous or supernatural . i. of the principles of things corporeal , none can be more few , without being insufficient , or more primary than matter and motion . ii. the natural and genuine effect of variously determin'd motion in portions of matter , is , to divide it into parts of differing sizes , and shapes , and to put them into different motions , and the consequences , that flow from these , in a world fram'd as ours is , are , as to the separate fragments , posture , order , and situation , and , as to the conventions of many of them , peculiar compositions and contextures . iii. the parts of matter endow'd with these catholick affections are by various associations reduc'd to natural bodies of several kinds , according to the plenty of the matter , and the various compositions and decompositions of the principles ; which all suppose the common matter they diversifie : and these several kinds of bodies , by vertue of their motion , rest , and other mechanical affections , which fit them to act on , and suffer from , one another , become indow'd with several kinds of qualities , ( whereof some are call'd manifest , and some occult , ) and those that act upon the peculiarly fram'd organs of sense , whose perceptions by the animadversive faculty of the soul are sensations . iv. these principles , matter , motion , ( to which rest is related ) bigness , shape , posture , order , texture , being so simple , clear , and comprehensive , are applicable to all the real phaenomena of nature , which seem not explicable by any other not consistent with ours . for , if recourse be had to an immaterial principle or agent , it may be such an one , as is not intelligible ; and however it will not enable us to explain the phaenomena , because its way of working upon things material would probably be more difficult to be physically made out , than a mechanical account of the phaenomena . and , notwithstanding the immateriality of a created agent , we cannot conceive , how it should produce changes in a body , without the help of mechanical principles , especially local motion ; and accordingly we find not , that the reasonable soul in man is able to produce what changes it pleases in the body , but is confin'd to such , as it may produce by determining or guiding the motions of the spirits , and other parts of the body , subservient to voluntary motion . v. and if the agents or active principles resorted to , be not immaterial , but of a corporeal nature , they must either in effect be the same with the corporeal principles above-nam'd ; or , because of the great universality & simplicity of ours , the new ones propos'd must be less general than they , and consequently capable of being subordinated or reduc'd to ours , which by various compositions may afford matter to several hypotheses , and by several coalitions afford minute concretions exceedingly numerous and durable , and consequently fit to become the elementary ingredients of more compounded bodies , being in most trials similar , and as it were the radical parts , which may , after several manners , be diversified ; as in latin , the themes are by prepositions , terminations , &c. and in hebrew , the roots by the haeemantic letters ▪ so that the fear , that so much of a new physical hypothesis , as is true , will overthrow or make useless the mechanical principles , is , as if one should fear , that there will be a language propos'd , that is discordant from , or not reducible to , the letters of the alphabet . finis . notes, typically marginal, from the original text notes for div a -e ps . . ps . . . ps . . . isa . . . rom. j. . genes . vj. numb . xxvij . . genes . xx . genes . xviij . kings iij. jonah iv . kings ▪ xxij . from ver . . to ver . . job j. , , &c. job ij . . see heb. v. . psal . ciij. , . acts j. . joh. iij. . revel . vij . . matth. xxvj . . dan. vij . . joh. j. . heb. j. . luke xx . , . col. j. . matth. xxiv . . mark xiij . . matth. xviij . . isa . vj. , matth. vj. . sam. xiv . . mark xiij . . king. xix . . thess . iv . . jude ix . dan. x. , . col. j. . revel . xij . . acts xij . , , , . dan. x. . acts xij . . kings vj. . luke xxiv . . judg. xiij . . heb. j. . revel . xix . . revel . xxij . . matth. xxviij . . revel . xix . . joh. j. coloss . j. . matth. viij . . luke iv . . joh. viij , . pet. v. . cor. xj . . revel . xij . . revel . xij . . matth. xxv . . joh. iij. . jude . mark v. , , . jam. iv . . pet. v. . cor. vj. . matth. xxv . . jam. ij . . pet. ij . . jude , . matth. xxv . . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . jam. iij. . pet. iij. ● , , . gen. ij . . acts xxiv . . acts xvij . , . gen. ij . acts xvij . . gen. ij . , . acts xxv . . luke xx . , . matth. x. . gen. ij . zek. xij . . luke xx . , . matt. xxv . . d●s cartes responsione ad objectiones secundas , pag. m. . mark xiv . . pet. j. . rom. xj . . gen. ij . , , . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . joh. v. . acts xx . . matth. xxvj . . dan. vij . . mark v. . luke viij . . dan. ij . , , &c. isa . v. . isa . lxv . . * * rev. j. . to render the original word ( observe , or ) watch , rather than keep , seems more congruous to the sense of the text , and is a criticism suggested to me by an eminent mathematician as well as divine , who took notice , that the word 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 is us'd by the greeks as a term of art , to express the astronomical observation of eclipses , planetary conjunctions , oppositions , and other celestial phaenomena . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . ephis . iij. ▪ isa . vj. , . luke ij . , . revel . v. , . gen. ij . , . seraph . love. psal . xxxij . . deut. viij . , , , , , , job xxxviij . , , . psa . l. . hos . xiv . . psal . civ . . psal . xix . . psal . cxxxix . . tim. ij . . joh. xiij . . heb. v. . joh. v. . search , or , you search the scriptures . coloss . iij. . prov. xxvj . . acts xvij . . pe● . j. , . pet. j. ● . psal . cxix . . revel . j. matth. xj . . mark iv . ● , . luke viij . . matth. v. . joh. iij. . 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 medit. tertia sub finem . exod. xv . . matth. v. , . tim. iij. . tit. j. . numb . xxj . . diogenis laertii libr. . iob iv . . psal . ciij. . cor. . . job xviij . . dan. ix . , . luke j. , . acts x. , , . pet. j. . luke xxiv . . psal . cxix . . acts xvij . , . jam. ij . . chron. vj. , . sam. vij . ver . . ver . . hab. j. . matth. v. . cor. v. . luke xx . . notes for div a -e ephes . iij. . see examples of this in my notes about sensation and sensible qualities . acts vij . . kings vj. . cor. xiij . . joh. iij. . gen. xxxvij . amos vj. . * * see the requisites of a good hypothesis . see this subject handled at large in an appendix to the author's ex●men of antiperistasis . * * in the history of cold. * * now publish'd in the book of new physico-mechanical experiments . see a tract on this subject , premis'd by the authour to his book of cold. amos vj. . sam. ij . . . chron. xxv . . rom. viij . . luke xxiij . . ● kings iij. . phil. ij . . heb. xij . . rom. ij . . matth. v. , . notes for div a -e 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 . enchyridion physicæ restitutæ, or, the summary of physicks recovered wherein the true harmony of nature is explained, and many errours of the ancient philosophers, by canons and certain demonstrations, are clearly evidenced and evinced. espagne, jean d', - . this text is an enriched version of the tcp digital transcription a of text r in the english short title catalog (wing e a). textual changes and metadata enrichments aim at making the text more computationally tractable, easier to read, and suitable for network-based collaborative curation by amateur and professional end users from many walks of life. the text has been tokenized and linguistically annotated with morphadorner. the annotation includes standard spellings that support the display of a text in a standardized format that preserves archaic forms ('loveth', 'seekest'). textual changes aim at restoring the text the author or stationer meant to publish. this text has not been fully proofread approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. earlyprint project evanston,il, notre dame, in, st. louis, mo a wing e a estc r ocm this keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the early english books online text creation partnership. this phase i text is available for reuse, according to the terms of creative commons . universal . the text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission. early english books online. (eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) enchyridion physicæ restitutæ, or, the summary of physicks recovered wherein the true harmony of nature is explained, and many errours of the ancient philosophers, by canons and certain demonstrations, are clearly evidenced and evinced. espagne, jean d', - . [ ], p. printed by w. bentley, and are to be sold by w. sheares ... and robert tutchein ..., london : . attributed by wing and nuc pre- imprints to d'espagne. reproduction of original in the harvard university library. eng soul -- early works to . physics -- early works to . nature -- early works to . a r (wing e a). civilwar no enchyridion physicæ restitutæ; or, the summary of physicks recovered. wherein the true harmonie of nature is explained, and many errours of espagnet, jean d' b the rate of defects per , words puts this text in the b category of texts with fewer than defects per , words. - tcp assigned for keying and markup - aptara keyed and coded from proquest page images - robyn anspach sampled and proofread - robyn anspach text and markup reviewed and edited - pfs batch review (qc) and xml conversion enchyridion physicae restitutae ; or , the summary of physicks recovered . wherein the true harmony of nature is explained , and many errours of the ancient philosophers , by canons and certain demonstrations , are clearly evidenced and evinced . london , printed by w. bentley , and are to be sold by w. sheares at the bible , and robert tutchein at the phenix , in the new-rents in s. pauls church-yard . . the authours epistle . to the honourers of natural light . after i had lately with-drawn my self from publick employments , & reprieved my soul from the dangerous attendants of a courtier's life , and had now ancor'd my thoughts in a blest retirement , i alwayes had resounding the eccho of that poetical passage in mine ears : here is the freedom the soul gains , enfranchiz'd from her golden chains . now began i to feel those thoughts of natural philosophie , alwayes fostered by me , though till now , as it were ill attended , to give a fresh and sprightly spring in my soul . i could not but upon their return , give them a wonted and merited well-come , that i might by the gain of this inward and natural light , repair my voluntarie ressignment of that outward and deceitfull splendour : besides , by this course , i had hopes to wipe off a publick guilt , for now did i apprehend the charge of a desertour of publick employments , and of the laws of my countrie likely to fall upon me , therefore lest this might issue a deep censure , i fled to that sanctuarie , the studie of the occult , and almost unsearchable laws and customes of nature in the universe , the common countrey of all , hoping a securitie in this studie , and a protection from this policie . for certainly civil constitutions will not decree any remarkable amercement upon him , who laying down the burden of those troubles , doth retire himself to the general service of the world . now was my soul rowling within it self thought concerning the sovereigntie , lawes , order , government , harmonie , effects , causes , yea , the unconceiveable riches of nature ; now indeed was i lost in admiration of these , which astonishment , though it be an evidence of ignorance , yet it is also an incentive to knowledge , for it causeth the soul to soar above , by which it is enkindled with a burning desire to know what it is , as yet ignorant of , though affected to . my soul being thus enflamed , brought several philosophical constitutions to a severe text , and upon the touch , assented not to their veritie , because nature did seem to dart some weak and waining light , as it were breaking forth upon the confine and border of a scarcely discerned truth , till at length , the light began so to rise , as to break through the encompassing fogs , and to break into my soul , whereby it was not onely made more resplendent , but also more confident , not onely to view the ground , but also to dig for the treasure . the first errours of the ancients , and which are the worst and radicall errours that came into my thoughts , were those concerning the principles of nature , concerning the first matter and that universal form , from which all things flow , concerning the number of the elements , their qualities , their opposition , scituation , reciprocation ; when i had seriously turned these within my thoughts , i layed hold of an opinion different from the current ; neither was the authoritie of ancient philosophers , nor their ingenious , but unsatisfactorie reasonings , able to divert my mind from that perpetual devotion , in which it stood to the light of nature . so now what i first admired , i now affected , yea , that love , which hath no weapons but fierie rayes , strook my soul into a flame , to enter into the most secret and sacred rooms of nature . but i was long in a suspensive dispute with my self , whether it were my dutie to communicate to you , the students of philosophie , those secrets i have found , suspicious lest it might prove a disgust to you , a danger to my self ; for i found experience the best counsellour to give me warning to be wise by the folly of others , and to learn to stand by their falls ; for i alwayes was musing how many had wrackt their credit by scribling , how our modern wits are close in their commendations , but lavish enough in their detraction of other mens labours , how attempting their souls are in fancying and fostering follies , how obstinate in the retaining a conceived truth ; yea , i considered it was not onely a project of difficultie , but also of danger , to pull up a received and an acknowledged opinion , and to implant a new and divers . but in this conflict , ( ye most ingenious assertours of natural light ) the victorie fell upon the love of you , and of truth , so that i was determined , that since those had been the motives to the disquisition of these truths , they should also be the incentives to their publication . yet let me have this boon granted , that if you will be competent or just judges , let not the swoln names of plato , aristotle , and of any other prime philosophers , be summoned as convicting witnesses ; or empannell'd as a condemning jury , but lay aside their nominal , though seemingly real authority , and bind not your souls to a continued credulity of their positions ; but preserve your souls free to your selves . in the reading of the learned monuments of former ages , let not the popular fancy of their general applause , bewitch you into a blind belief of all their notions . far be it from me to stain their credit , or detract from their learning , who alwayes had exhibited by me almost a divine adoration , there is no earthly glory competible to theirs : they were the men that first took infant philosophie into their arms , and nourished it up to so incredible a strength and stature , that those lofty souls seemed to have cut off from succeeding ages , the hope of an addition to their labours , and to an advancement of learning . yet as for the deep search of the winding creeks of nature , and for the exquisite knowledge of her concealed mysteries , the growing age of philosophie , even in its own judgement , did not comprehend them , these were brought forth by the fertile brains of future times , they brought to light obscurities , they polish'd rough-hewn principles , they propt up perplexities . so did knowledge get its accomplishment by age , and truth its perfection by time , which demonstrates the vigour of our present years , and that the number of things we know , is far less than of those of which we are ignorant . philosophy is not like a garment , as that age should wear it or worse it , and they that pretend a gray head to their errours , by this seek not so much to patronize it , as to discredit it . forbear i beseech you , by an unadvised censure , to condemn me without plea , if i shall seem to unsettle the boundaries of philosophy , be not angry , and accuse me as sacrilegious , but consider whether i do not aym at their settlement rather than otherwise ? whether i do not rather confirm than weaken her priviledges ? whether i do not rather honour than impayr her royalty ? upon which grounds i hope she will , as by way of requital , not deny me her assistance , as a buckler against the delusions of sophisters , and a breast-plate against the environed darts of either envy or ignorance . these beasts will bark , the first pining at anothers good , the second raging in its own clouds , both break into the cultivated gardens of knowledge , and the delightfull paradise of philosophy , and either snip or blast the endeavours of a more fortunate genius . these to no purpose strive to stop my course by their frights , i am seated above their highest reach ; as long as i can see the deity of truth , under her patronage i walk , i work secure . onely be you pleased to accept these sprinklings of my retirement , with the same soul it is presented , if any thing seem in it to disrellish , deal so gently as that you may seem rather not to comply , than wholly to refuse . i shall in the interim reach my end , if my pains shall cause you to fall upon greater attempts with better success . enchyridion physicae restitutae . or , a summary of the physicks recovered . the first rule . god is an eternal being , an infinite oneness , the radical principle of all things , whose essence is an incomprehensible light ; his power , omnipotency ; whose beck is an absolute act . he that dives deeper , is swallowed up in a trance and silence , and is lost in the abyss of unfathomed glory . . most of the ancients conceived the world from eternity to have been figured in its archetype , and original , which is god , who is all light : before the creation of the universe he was a book rowld up in himself , giving light onely to himself ; but , as it were , travailing with the birth of the world , he unfolded himself , and that work which lay hid in the womb of his own mind , was manifested by extending it to view , and so brought forth the idaeal-world , as it were in the transcript of that divine original , into an actual and material world . this is hinted by trisgmegist , when he says , that god changed his form , and that all things were in a sudden revealed and brought to light . for the world is nothing else but the disclosed image of an occult deity . this beginning of the world the ancients seem to have denoted by the birth of their pallas , out of the brain of their jupiter , by the mid-wiffery of vulcan , that is , by the help of divine fire or light . . the eternal parent of all things , not less wise in governing , than powerfull in creating , did so orderly dispose the whole organical frame of the world , that the highest are so intermixt with the lowest , and the lowest interchangeably and inconfusedly with the highest , and have an analogical likeness , so that the extreams of the whole work by a secret bond , have a fast coherence between themselves through insensible mediums , and all ●●●●gs do freely combine in an obedience to their supream ruler , and to the benefit of the inferiour nature , onely being subject to a dissolution at the will of him who gave them their constitution . wherefore it is well said of hermes , that whatsoever is below , hath an assimulation to somewhat above . he that transfers the sovereign order of the universe to any nature diverse from the nature of god , denies a god . for it cannot be just to conceive any other uncreated deity of nature , as the cause of the production or conservation of the seve●al individuals of this large frame of the world , besides that spirit of the ●ivine worker , which lay upon those first waters , and brought forth the seeds of all things , confusedly rowld ●n the first chaos , from their power into act , and wheeling them by 〈◊〉 perpetual alteration , doth mannage them geometrically by composition and resolution . . he that knows not the soul o● the world to be that spirit , the creatour and governour of the world , by its cont●●●ed infusion , o● its breathing upon the works of nature , and by its enlarged diffusio● through all things , giving to al● things a set , but secret motion according to their kind : he is wholly an ignaro of the laws of the universe for he that created , cannot but assume the power of ruling what is created , and it must be acknowledged , that all things have their creation , generation and conservation by the same spirit . . notwithstanding this , he thi● shall grant nature the honour of being the second universal cause attending on the first , and as it wer● an instrument moved by it , and 〈◊〉 giving , according to a material order , an immediate motion to ever● thing in the world , will not spe●● what disagrees with the opinion 〈◊〉 philosophers or divines , who 〈◊〉 that natura naturans : i. nature giving nature : this , natura naturata , nature made nature . . he that is verst in the secrets of nature , will acknowledge this second nature the attendant of the first , to be the spirit of the universe , or the quickening virtue of that light created in the beginning , and contracted into the body of the sun , and endowed with an hidden faecundity . zoroaster and heraclit called this the spirit of fire , the invisible fire , the soul of the world . . the order of nature is nothing else than a large rowl of the eternal laws , which being enacted by the highest sovereign , and recorded and written in various leaves to innumerable people of a various nature , by the auspicious power of which laws , the frame of the universe doth accomplish its motions , life and death always atttending on the margins of the last volume , and the other spaces being taken up by alternal motions . . the world is as it were a smithswork made orbicular , the links of the chain enclasping it , each the other , are the parts of the world , nature as it were deputed to sit in the middle , always present , and ever working , continually repairs the changes and motions of all things . . the whole world , as it hath its constitution from a three-fold nature , so hath it its distinction into a three-fold region , viz. the super-celestial , the celestial , the sub-celestial . the super-celestial is that which is otherwise termed the intelligible , it is altogether spiritual and immortal , having the nearest approch to the divine majesty . the celestial is seated in the middle , which having allotted to her the portion of the most perfect bodies , and being replenished with spirits , doth pour out by the conveyance of spiritual channels , numberless efficacies and vital breathings , not enduring a corruption , onely having attained its period subject to change . lastly , the sub-celestial , or elementary region , hath its assignment in the lowest portion of the world . this being wholly of a corporeal nature , doth enjoy spiritual gifts and benefits , ( the chief of which is in life ) by loan onely , and upon request , being as it were to repay heaven for it . in the bosom of this region there is no generation without corruption , no birth without death . . it is enacted and setled by the laws of the creation , that the lowest things should immediately be subservient to the middle , the middle to those above , these to the subpream rulers beck . this is the symmetry , the order of the whole universe . . it is the excepted priviledge alone of the creatour , as he created all things according as he pleased out of nothing , so to reduce what he hath created into nothing : for whatsoever being or substance hath an impress from him , cannot deny subjection to him , but is prohibited by natures law , to return to a non-entity . therefore trismegist did truly assert , that nothing in the world doth die , but pass into a change , for mixt bodies have their composition from the elements , which by natures rotation are again resolved into the elements . hence is this sequel , that by natures cost all 's cloth'd with what 's its own , nothing is lost . . the philosphers did believe a first matter to be of an elder birth to the elements , but this as it was ▪ but scarce apprehended by them , so was it as briefly , and as it were in the clouds , and obscurely handled by them , they made it void of qualities and accidents , yet the first subject of them without quantity , yet by which all things have their dimensions , endowed with simplicity , yet capable of contraries , without the reach of sensible knowledge , yet the basis of sensible , drawn out through all places , yet unperceiveable covetous of all forms , tenacious of none , the root of all bodies , yet not sensible but conceiveable , onely by an act of the intellect : lastly , nothing in act , all things in aptitude . so have they laid a fancy for the foundation of nature . . aristotle more wary , though he believed the eternity of the world , yet hinted a certain first and universal matter . in the discussion of this he used sobriety and ambiguity , alwayes avoiding its creeks and perplexities , so that he opined it better to conceive * one inseparable matter of all things , which yet hath a respective difference , from which , the first bodies with the rest , which are under sense , have their subsistence ; that this is the first principle of them , and not to be separated from them , † but always joyned with a repugnancie , always subject to contraries , from which the elements are produced . . the philosopher had been righter , if he had asserted that first matter free from the conflict of contraries , and disengaged from that pretended repugnancy , since there is no contrariety inherent in the very elements , but what is the result of the intention of their qualities , as we are informed by the daily experience of fire and water , in which , whatsoever opposition there is , ariseth from the heightening of their qualities . but in the proper and true elements , which couple in the generation of mixt bodies , those qualities which are in a remiss degree in them , are not repugnant each to other : for their temperature doth not admit a contrariety . . thales , heraclitus , and hesiodus accounted water the first matter of all things , to whose opinion the writer of the holy genesis seems to consent : this they call an abyss and water , by which i guess they understood not our ordinary water , but a kind of sume , or moist and dark vapour , roaving here and there , and driven in an uncertain motion without any certain order . . i am not at present able to lay down any positive determination concerning that first principle of things , since it being created in the dark , could never by mans invention be brought to light , therefore whatsoever the troup of philosophers and divines do opine , whether these things are so or no , the authour of nature alone knows , therefore pardon is to be allowed to him that in dark doctrines hits what is most likely . . some of the rabbines agreeing , conceived an ancient , but obscure and inexpressible principle , the matter of all improperly called hyl● , which is more properly termed not so much a body , as a large shadow , not a thing , but a dusky image of a thing , or the smoaky appearance of an entity , a most dark night , a covert of clouds , actually all nothing , potentially all things which cannot be found but in fancie , and understood in a dream . our imagination cannot exhibit to us this doubtfull principle , this depth of darkness , no more than our talk can through the ears imprint the knowledge of the sun into a man that was born blind . . the same men had an opinion that god brought forth and created the nearest approching matter of the elements and the world , to wit , that dark , formless , and indigested abyss out of that farthest principle : the scripture calls this mass sometimes earth void and emptie , sometimes waters , although actually it were neither , yet potentially and by way of assignment , it was both : we may give a propable guess that it was not unlike to a dark smoak or vapour ▪ in which was closed a stupifying spirit of cold and darkness . . the division of the higher waters from the lower , expressed in genesis , seems to be done by the severing the subtile from the thick , and as it were a thin spirit from that smoaky body ; there was needfull therefore of that lightsom spirit proceeding from the word of god . for light , which is a fiery spirit , by separating things of a diverse nature , did drive down the thicker darkness from the nearest and highest region , and uniting the matter of one and the same kind , being of a thin and a more spiritual substance , inflamed it as an unquencheable oyl , to burn before the throne of the divine majesty . this is the empyraean heaven , seated between the intellectual and material heaven , as the horizon and finitor of each , receiving spiritual endowments from that above , and deriving them down to the inferiour adjoyning middle heaven . . reason required that this dark abyss , or next matter of the world , should be watry and moist , that it be the better subject to be attenuated , and that by this flux of the matter by attenuation , the whole frame of the heavens and of the rest of the fabrick , might issue forth , and might be laid out in a continuous body . for it is the property of moisture to flow , and the continuity of every body is the effect of the moisture of it . for moisture is the glue and joyncture of elements and bodies . but fire acting upon moisture by heat , doth rarifie , for heat is the instrument of fire , by which it doth act two opposite works by one and the same labour , separating the moist nature from the earthy , & by rarifying that , condenseth this : so that by the separation of the things of a diverse , proceeds a congregation of things of the same nature . by this first principle of chymistry , the uncreated spirit , the artifex of the world , did distinguish the confused natures of things . . the architectonique spirit of the world began the work of creation from two universal principles ; the one formal , the other material , for otherwise what is the meaning of the words of the prophet , gen. . god created the heaven and the earth ? &c. unless that in the beginning of the information of the matter , he distinguished it into two chief principles , a formal and a material heaven and earth ; by the word earth , is to be understood that dark , and as yet unshaped mass of the waters and abyss , as is apparent by the subsequent words , ( the earth was void and without form , and darkness was upon the face of the depth , &c. ) which the creatour did shut in and comprise within the highest , to wit , the empyrean heaven , which is natures first formal , though farthest principle . . for the spirit of god , which is the brightness of the deity , being poured out upon the waters , that is , upon the moist and large surface of the depths , in the very moment of creation , light presently broke up , which in the twinkling of the eye , surprized the highest and more subtile part of the matter , and encompassed it as it were with a fringe , and border of light , as that lightening is which is darted from the east to the west , or like a flame which fires the smoak . so was the birth of the first day , but the lower portion of darkness devoid of light , continued night , and so the darkness had its division into day and night . . concerning that first heaven , that formal principle , it is not declared to have been void , empty , and wrapt in darkness , which is a sufficient evidence , that that heaven which was first spread out , was forthwith severed by the light from the subjacent dark mass , by reason of the nearness of the glory and majesty of god , and the presence of that lightsom spirit flowing from it . . there was therefore in the beginning two principles of all things created , one full of light , and bordering upon the spiritual nature , the other wholly corporeal and dark ; the first , that it might be the principle of motion , light , and heat ; the second , of a drowsie , dark , and cold being : the first active and masculine , the other the passive and feminine principle . on the part of the former comes a motion in the elementary world to generation , from whence proceeds life ; from the other part comes the motion to corruption , the principle of death . so that is the double fringe or border of the lower world . . but because love is extensive , and acts without from it self , the divine nature impatient of its solitude , and taken with its own beauty in the light already created , as in a mirrour , and earnestly desirous to enlarge it , and to multiply his image , commanded that light to be extended and propagated . then the light , the fiery spirit issuing from the divine understanding , and rowling it self in a circulation , began to work upon the nearest darkness , and having prevailed upon it , and sunk it down towards the centre , and there sprung forth the second day , and there was seen the second mansion of light , or the second heaven , comprizing all the airy region , in whose higher region are so many torches kindled and scattered : in the lower are seated the seven wandering stars according to their order , that they might , as so many presidents and rulers , give orders by their light , motion and influence to the subjacent nature . . and least any thing should be defective in this great work , already drawn out in the mind of god , the same spirit by his glittering and fiery sword beat off the banded darkness , and that shade that lay under him , and thrust it down into the centre of the abyss , so the lowest part of the heavens was enlightened , which we rightly term air , or the lowest heavens : then was the third day . but the darkness which at first did overcast the whole face of the abyss , being thrust down by the supervening light into the lowest region , was so thickened by reason of the straitness of the room , and the binding force of the cold , that it passed into a huge mass of a watry nature , the kernel and centre of the whole workmanship , as it were a dale and heap of darkness , being poiz'd in the middest of the waters , and bound up of the dregs and thick matter of the abyss , into a firm and dark body of earth . after this , upon the driving of the spirit , the waters fled from the surface of the earth , casting themselves about the borders of it , and there appeared drie land , that it might produce almost an infinite number of several sorts of plants , and receive as guests so many kinds of creatures , especially man the lord of all , and provide to them food , and to man a plentifull sufficiency of all conveniencies . the earth therefore and the water made one globe , by reason of whose thickness , the shadow , the image of the dark abyss , doth continually beset the whole region of the air bordering upon it , and opposite to the sun , for it shuns and flies the assayling light , and so in the assault is upon a continual retreat . . that light , which upon the conquest and destruction of the darkness , had seized upon and spread it self upon the parts of the abyss , it seemed best to the great creatour to contract into that most resplendent and illustrious for quantity and quality , for bigness and beauty , that globe of the sun , that as the light was more narrowly pent , so it might be more efficaciously powerfull , and might dart its beams with more vigour , as also that the created light , the nearest approching nature to the divine glory , proceeding from an uncreated unity , might through its unity be poured out upon the creatures . . from this glorious lamp of the world do all the other bodies borrow light ; for that dark shade which we sensibly perceive in the globe of the moon , by reason of the neighbouring earth , and the extension of her shadow , we may credibly guess the like to be in the other globous bodies , though not perceivable by reason of their distance . indeed the prime and most principal nature of sensibles , the fountain of light , ought to be one , from which these things below might receive the breath of life . whence is that true saying of the philosopher , the sun and man beget man . . it was not an improbable assertion of some of the philosophers , that the soul of the world was in the sun , and the sun in the centre of the whole . for the consideration of equity and nature seem to require , that the body of the sun should have an equal distance from the fountain and rise of created light , to wit , the empyrean heaven , and from the dark centre the earth , which are the extreams of the whole fabrick , whereby this lamp of the world , as a middle nature and joyner of both extreams , might have its scite in the middle , that it may the more commodiously receive the rich treasuries of all powers from the chief spring , and upon a like distance convey them to things below . . before the contraction of this light into the body of the sun , the earth spent an idle time in its solitude , looking for a male , that being impregnated by his copulation , it might bring forth all sorts of creatures , for as yet it had been delivered onely of abortives and embryoes , to wit , of vegetables onely . for the weak and faint heat of that scattered light , could not get the conquest of that moist and cold matter , nor put forth its virtue in any higher actings . . from the light therefore the elements , as well as the first matter , had their information , and so attained a joynt nature of light , and by kindred a fast friendship betwixt themselves , not according to the vulgar opinion , an hatred and quarrel ; they embrace each the other with a common bond of friendship , that they may joyn themselves to the making up of several mixed bodies , according to their several kinds . but the light of the sun being of a far greater power than this former , is the form of all forms , or the universal form which doth convey all natural forms in the work of generation , into the disposed matter and seeds of things . for every particular nature hath within it a spark of light , whose beams do in a secret māner attend with an active & motive power . . it was necessary that the entire portion of the first matter , allotted to this lower region , as well as the elements who did flow from it , should be seasoned from the beginning with a light tincture of that first light , whereby they might be the better fitted to receive that greater and more powerfull light in the information of mixt bodies . so fire with fire , water with water , light with light being homogeneous bodies , have a perfect union . . from the sight & efficacy of the sun , we may inferre that he is in the stead of an heart to the universe , for from him is life derived to all parts , for light is the chariot of life , yea , the fountain and next cause , and the souls of creatures are the beams of that heavenly light , which do breath life into them , exempting onely the soul of man , which is a ray of the super-celestial and uncreated light . . god hath imprinted in the sun a threefold image of his divinity , the first in his unity , for nature cannot away with a multiplicity of suns , no more than the deity can with a plurality of gods , that so one may be the spring of all . secondly , in its trinity , or his threefold office . for the sun , as gods vicegerent , doth dispense all the benefits of nature by light , motion , and heat : from hence is life , which is the supream and most accomplisht act of nature in this world , beyond which cannot go , unless backward . but from light and motion issues heat , as the third in the trinity proceeds from the first and the second person . lastly god , who is the eternal light , infinite , incomprehensible , could express and demonstrate himself to the world onely by light . let none therefore wonder , why the eternal sun did beautifie that most excellent draught of himself , which was his own making , that heavenly sun with so great endowments , for in him hath he pitcht his pavilion . . the sun is a transparent mirrour of the divine glory , which being seated above the sense & strength of material creatures , did frame this glass , by whose resplendency the beams of his eternal light might be communicated by reflection to all his works , and so should by this reflection be rendered discernable . for it is beyond the capacity of any mortal to have any immediate view of that divine light . this is the royal eye of the divinity which doth conferre by his presence , life , and liberty to his suppliants . . the last work of this great worker , and as it were the corolary and shutting of all , man enters 〈◊〉 summary of the worlds fabrick , 〈◊〉 small draught of the divine nature . the creatour deferred his making to a part of the sixth light , ●nd the last of all his working , that the rich furniture of nature , and ●ll endowments of things both above ●nd below , might bring their confluence to the humane nature as to another pandora . thus the things of the world being ordered , man wanted onely to be annexed as the perfection of all ; whereby nature , being now strengthened by a various light , might bring into his perfect temperature more refined elements , and that there might be the best clay for the forming of so exquisite a vessel . yea , the lower globe and the inhabitants of it did require such a governour , lest otherwise they might refuse his rule . upon the sixth day from the creation , the third day of the suns rising , did man rise out of the earth : by the time of his production , and the number of the days is shadowed forth a great mysterie . for as upon the fourth day of the creation the whole light of the heaven was gathered into the single bodie of the sun , and on the third day from the making of the sun , which was the sixth day from the beginning of the creation , the clay of the earth received the breath of life , and was formed into a living man the image of god : so on the fourth millenary day from the beginning of the world the uncreated sun , viz. the divine nature , infinite and never before comprehended within any bounds , was willing to be comprized , and in a manner shut into the cage of an humane bodie . upon the third day or millenarie ( for a thousand years with god are but as one day ) after the first rising of that sun , and about the end of the sixth day , to wit , of the millenarie from the creation , shall fall out the glorious resurrection of the humane nature in the second coming of that supream judge , which was also praesignified to us by his blessed resurrection on the third day . so did the prophet in his genesis roul up the secret age and destinie of the world . although the almightie , according to his pleasure , created the world , yet could have brought it out of darkness into light ( if his will had so been ) in a moment , and by a beck : for he said , and it was so . yet the order of creation of principles , and successively of the natures according to their times , was set in the mind of god , which order , rather than the work it self of creation , that sacred philosopher seems to describe in his genesis . there seems to have been in the beginning a threefold way of the information of the first matter . for in what portion of the matter there was an irrational lightsom form , and without proportion above the rest , as in the empyrean heaven , where the light first seized upon the matter , then the form having as it were an infinite virtue , did swallow up its matter , and translated it into a nature almost spiritual and free from any accident . but where the virtues of the form and matter did meet in an equal poyz and a just equallitie , according to which , the aetherial heaven , and the celestial bodies are informed , there the action of the light , whose force in acting is of greatest power , did proceed so far , that it did rescue its matter from all original blemishes , as also from the loathsom infection of corruption after a wonderfull sort , by illumination and attenuation , and this is to be accounted as a truly perfect information . the third way of informing the matter is , in which a weaker form remains , as it often happens , though after divers ways in this our elementarie region , in which the appetite of the matter , which is an evidence of weakness and imperfection , luxuriating , and lavishly springing in its basis and root , cannot be sufficiently satisfied , by the reason of its remotion and distance from its former principle , neither can this weakness be cured . hence the matter not being fully informed according to its desire , languisheth under the desire of a new form , which having attained , it doth bring to it , as to its husband , the dowrie , a large wardrobe of corruption and faults . this sullen , perverse wrangling and inconstant matter , doth always burn for new beds , greedily wooing all forms which it longs for if absent , hates , if present . by which it is evident , that the leaven of alteration and corruption , and at length the fatal venom of death do happen , not from the repugnancie of qualities , but from an infected matrix , and from the menstruous poyson of a dark matter , and this causeth it so to fall out both in elements and in the mixt bodies of this lower region : because the form weakned and insufficient by its defilement and imperfection , and being not of a just poiz and assize , could not purge it out in its first and radical union . this is confirmed by holy writ , in which we may observe our first parent was not created according to his matter immortal , but that he might be guarded from the tincture and corruption of the matter , and therefore god set in paradise a tree abounding with the fruit of life which he might make use of as his assertour & guardian from the frailty of his matter , and the bondage of death , from the presence and use of this he was sequestrated after his fatal fall , and final sentence . two there were therefore first principles of nature , before which were none , after which all , to wit the first matter , and its universal form , by the copulation of which issued the elements as second principles , which are nothing else but the first matter diversly informed ; out of the mixture of this is made the second matter , which is the nearest subject of accidents , and doth receive the various turns of generation and corruption . these are the degrees , this the order of the principles of nature . . those who annex to the matter and form , a third principle , viz. privation , do blast nature with a calumnie , far from whose purpose it is to admit a principle that shall go counter to her intention , but her end in generation being to obtain a form , to which privation is adverse , certainly this cannot be part of natures aim : they had spoken more to the purpose , if they had made love a principle of nature , for the matter being widowed in its form , covets eagerly the embracing of a new . but privation is the meer absence of a form , upon which ground the honourable title of being a principle of nature , is no way due to it , but rather to love , which is a mediatour betwixt that which desires , and that which is desired , betwixt what is beautifull , and what is deformed , betwixt matter and form . . corruption is far nearer than privation to the principle of generation , since that is a motion disposing the matter to generation by successive degrees of alteration ; but privation acts nothing , is of no work in generation , but corruption doth both promove and prepare the matter , that it may be put in a capacity of receiving the form , and as it were a mediatrix , doth act pander-like , that the matter may the more easily get a satisfaction for its lust , and by his help may the sooner obtain the copulation of a form : corruption therefore is the instrumental and necessary cause of generation . but privation is nothing else but a meer vacancy of an active and formal principle : and darkness was upon the face of the depths , to wit , of the uninformed and dark matter . . the harmony of the universe consists in the diverse and gradual information of the matter . for from the poized mixture of the first matter and its form , flows both the difference of the elements , and of the region of the world , which is briefly , but truly set out by hermes , when he said , that whatsoever is below , hath an assimulation with somewhat above . for things above and below , were made of the same matter and form , differencing onely in respect of their mixture , scite and perfection , in which the distinction of the parts of the world , and the latitude of all natures , are handled . . we must believe that the first matter , after it had received information from the light , and was distinguished by it into several things , did go wholly out of it self , and was transmitted into the elements , and that which was compounded by them , and was wholly exhausted in the consummation of the work of the universe , so that those things which were closed in her , being brought forth , and exposed to view , she began wholly to lie hid in them , and we must acknowledge it is not to be found in a separation from them . . nature hath left us a shadow of that ancient confused mass , or first matter in drie water , not wetting , which rising out of those impostumes of the earth or lakes , doth spring forth big with a manifold seed , being also volatile by reason of its lightness through its heat , from which being coupled with its male , he that can take out and separate , and joyn again ingeniously the intrinsecal elements , he may well boast that he hath gained the most precious secret of art and nature ; yea , a compendium or brief of the heavenly essence . . he that searcheth for the simple elements of bodies , separated from all mixture , takes a labour in vain , for they are unknown to the most piercing judgements of men , for our common elements are not the simple element , yea , they are inseparably mixed one with another . the earth , water , and air , may be more truly called the parts that perfect and compleat the universe , rather than elements , yet they may be rightly termed the matrix's of them . . the bodies of earth , water , and air , which are sensibly distinguished by their sphears , are different from the elements which nature maketh use of in the work of generation , and which make up mixt bodies , for these in their mixture in respect of their thinness , are not discernable , but are barr'd from the senses , until they conjoyn in a condensed matter and body . there never hath a creature been , whose principles were to be seen : but those things which fill up the inferiour globe of the universe , as too thick , impure , and indigested , are debarred from the right of perfect generation , for they are rather the shadows and figures of elements , than true elements . . those elements which forming nature makes use of in her mixtions , and in making bodies , although they are not to be found out before mixtion , yet in the finished work , and in the compleatly mixed body , because their parts have a correspondence proportionable with the parts of the world , and have a kind of analogie with them , we may call them by the same names , the more solid parts , earth ; the moister , water ; the more spiritual , air ; the inborn heat , nature's fire ; the hidden and essential virtues ; a man may safely term heavenly and astral natures , or the quint-essence , and so every mixed body may by this analogie triumph in the title of micro-cosme . . he that did appoint the first elements for the generation of bodies , alone knows how out of them to make all particulars , and to resolve them , being made , into them again . . let not them therefore refuse the light , who working about the elements of nature , either in the production of some body from them , or the resolution of some into them , create their own trouble , since these elements are onely subject to the dominion of nature , and delivered to her onely from their beginning , altogether unknown to all our art , and not compassible by our endeavours . . the element of nature may be termed the most simple portion of the first matter , distinguished by its peculiar difference and qualities , constituting a part of the essence in the material composition of mixt bodies . . by the elements of nature , are denoted the material principles , of which some have a greater purity and perfection than others , according to the greater power and virtue of that form that gives the compleatment . they are for the most part distinguished according to their rarity or density , so that those that are more thin , and approch nearer to a spiritual substance , are therefore the more pure and light , and so are the more fit for motion and action . . upon this ground it was that reverend antiquity did seign , that the whole empire of the world was divided between the three brothers , the sons of saturn as coheirs , because it acknowledged onely three elementary natures , or rather three parts of the universe . for by jupiter , the omnipotent , who shared heaven as his portion , armed with his treble-darted thunder-bolt , superiour to the rest of the brothers , what did those professours of mysteries understand , but that the heavens , being the region of heavenly bodies , do assume a priviledge of sovereignty over these inferiour beings . but they placed juno , wife to jupiter , to praeside over the lowest region of the heaven , or our air , because this region troubled with vapours , being moist and cold is as it were in a manner defiled and impure , and nearest approaching to a female temperament , as also because it is subjected to the orders of the higher regions , receive their effects , and communicates them to us , twisting it self with more condensed natures , and stooping them to the bent of heaven . but because male and female differ onely in sex , not in kind , therefore would they not have the air , or the lower heaven to be distinct in its essence and kind , as another element from the higher heaven , but onely diversified in place and by accidents . to neptune the god of the sea , they attributed a dominion over the waters . by pluto , the lord of the lower parts , abounding in wealth , they denoted the globe of the earth replenished with riches , with the desire of which the minds of men being inflamed , are bitterly tormented . so that those wise men admitted of three parts of the universe , or if you please , of three elements , because under the nature of heaven they comprized the name of fire , and therefore did they draw jupiter armed with his thunder . . we are schollars to experience in this , that all the bodies of mixt beings , have their analysis and resolution into drie and moist , and that all the excrements of creatures , are terminated by the same differences ; from whence it is clearly evident , that their bodies are made up onely of two sensible elements , in which notwithstanding the other are virtually and effectually . but air , or the element of the lower heaven , is not the object of our sense , because in respect of us it is a kind of spiritual being . the fire of nature , because it is the formal principle , cannot be wrought to any separation or comprehension by any destruction by way of resolution , nor by any art or artifice of man . for the nature of forms is not subjected to the censure of the senses , because of its spiritual being . . the earth is the thickest body of the universe , therefore is it accounted the heaviest and the centre of it , we must assert its nature contrary to the received opinion , to be accidentally drie , because it doth retain most of the close and dark nature of the first matter , but a shade and darkness are the coverts of cold , from whence they flie the light , and are diametrically opposite to it , but the earth , in respect of its extream density , is the mother of shade and darkness , hardly passable by light and heat , therefore roughly knit by an heightened cold . and for this reason black choller is to be esteemed the coldest humour of all , because it is under the power of the earth , the earth under saturns , who is accounted the authour of a cold and melancholick temperature . further , those things that are ingendered in the bowels of the earth , of the substance of the earth , as marble and stones are of a cold nature , although we must otherwise conceive of mettals , because they are rather of an airy nature , and have in them sparkles of the fire of nature , and a spirit of sulphur congealing their moist and cold matter . yet mercurie surpassing the rest in moisture and cold , is beholding to the earth for his coldness , and to the water for his moisture . it is otherwise with those things that are produced in the sea , as in amber and coral , and many other things that have their beings from the sea and fresh waters , which as it is apparent , are of a hot temper , so that we have this instruction both from reason and experience , that the greatest coldness is to be attributed to the earth , not to the water . . but driness doth agree to the earth accidentally onely , and in a remiss degree ; for it was created in the middest of the waters , and the order of beings required , that in respect of its gravity , being sunk in the waters , it should never separate from them ; but the creatour using his prerogative , having removed the waters , gave to it an open surface , that so there might be room made both for the creation of mixed beings , and for their habitation . the earth therefore was enfranchiz'd from its natural yoke of bondage and subjection to the waters , not by any order of nature , but by a priviledge of favour , that so having its face wipt , it might lift up a dry visage to the view of the heavens , and might partake of the welcome light of the world . . every cold and drie is averse from the faculty of generation , unless it be helped out by some eternal helps ; therefore it was the will of the supream authour of nature , to heat the cold womb of the earth with an heavenly fire , and adjoyned to the drie globe of the earth the moist nature of water , that so by the mixture of two generative causes , moist , and hot , the sterility of the earth might be helped , and that by the mediation of the concourse and mixture of all the elements , the earth might be made a natural vessel for fruitfull generation . therefore all elements , and all qualities are in the earth . . the body of the earth was rightly created by the great god of a spongeous nature , that so there might be a receptacle for air , showers , and heavenly influences , and also that the moist vapours being expelled by the force of inward heat , from the centre to the superficies , through the porous passages of the earth , might by a mean putrefaction corrupt the seeds of things , and so prepare for generation ; these being thus disposed , receive that enlivening and heavenly heat . for nature hath sunk in the depths a magnetick love , by the actings of which they draw down , and suck out the efficacy and virtue of things above , which do increase the strength of the information , and hasten the sweetness of vital air . . the heat that comes from the inwards of the earth , is moist and impure , and doth corrupt by reason of the tainted mixture of earth and water ; but the most pure and heavenly doth generate by excitation , dilatation , and furthering the inbred heat to life , even that inbred heat which is hidden in the seeds of things , and as natures secret closed in their centre . but because both these heats are of the same kind , they have a joynt and amicable operation in the act of generation , and are inseparably united , until they are brought forth to life and large vegetation . . water is of a middle nature , betwixt what is thick and what is of a thin nature , betwixt the earth and the air ; natures menstruum , a volatile body , flying and not enduring fire , drawn forth by a moderate heat into a vapour , assuming multiplyed shapes , more unstable than proteus . . the moist element is mercurie , which sometimes assuming the nature of a bodie , sometimes of a spirit , doth attract to himself by his revolutions , the virtues of superiour and inferiour beings , and as it were receiving their instructions , doth trade in commerce as their agent or factor , amongst the remotest natures of the universe , neither will he leave his trafficquing till all the elements of the corruptible nature receive their fixation and purgation by fire , and there issue upon it an universal sabbath . . water , being the nearest in nature to the first matter , doth easily receive her impress . the chaos , the ancient parent of all things , was a kind of subtile and dark vapour , a kind of a moist dark substance , like a thin smoak , from whose most subtile part the heavens are drawn forth into order , which a three-fold difference divides into a three-fold province ; to wit , the supream , which is the noblest , the middle which assumes the second place of dignity and honour , the lowest is inferiour to the other two both in scite and honour . the thicker substance of the matter went to the making of that watry heap , which is a middle nature . the thickest part , which is as it were the dregs of the whole mass sate down to the bottom , and was setled for the globe of the earth . the extremities of this artifice , to wit , the heaven and the earth , did recede more from the first state of their matter , and from their ancient shape ; the heaven in regard of its great rarity and levity , the earth in respect of its great density and gravity . but the water , which was a mean betwixt them , continued a nature more like the first formless abyss from whence it proceeds , so that with ease it turns it self by rarefaction into smoak or vapour , which is the image of the ancient hyle , or first matter . . moisture is more proper to water than coldness , because water is of a greater rarity , and more lightsom than earth , but those things which communicate most of light are farthest off from cold ; the mor●rarity there is in any thing , the nearer vicinity there is to light . wate● retained the symbole of moisture from the first matter the abyss , as the earth coldness . for the architect spirit of the world divided the more thick parts into those two nearly-allied natures . . coldness wooes driness , and invests it self with it where it is vigorously predominant by the constriction of moist beings , and by the desiccation of them , as is evident in snow , ice , and hayl . for it is the work of nature to bind and drie the water , than which nothing is more humid by the proper instrument of cold ; yea , the principal and common subject of heat and cold , is humidity , by both which it is so strongly assailed , till it be conquered : from whence it falls out , that in autumn so many drie leaves fall at the first cold , that the stalks of feeble plants upon the strength of winter , in the height of drought , are void of moisture , and drie away : the cold penetrating doth so scorch , and makes so furious an assult upon the vital humours : hence proceeds flaggy and withered age , at length death comes and cuts down all with his well-set sickle , and sweeps you into his general granary . how then can any one conceive cold to be friendly to moisture , and to be its inherent property ? since nature suffers not the elements to act against each other , lest they should destroy and oppose each the others powers , but an intense cold quickly would bring under a remiss and weak moisture , and would swallow it up all by a violent constriction : so that by this means one of the elements being lost , there would necessarily follow an imperfection in the work of the rest , and a deficiency in the generation of all things . it is therefore not suitable to the law of nature , to invest water with the property of being cold in the highest degree . . out of these solider natures of earth and water , doth nature extract her elements , by which she compacts vessels and corporeal organs : for out of the commixture of both is made a clay , which is the next matter of things in generation : for it is in stead of the chaos , in which virtually and confusedly are all elements . out of this clay was the first father of mankind created , and after all generation issued from it . in the generation of creatures , is a clay made of the seed and the menstruum , from whence proceeds the living creature . in the production of vegetables , the seeds do first fall into a subtile clay by putrefaction , and then are wrought up to a vegetable body . in the generation of mettals , there comes forth a clay from the perfect mixture of sulphur and mercury , and their resolution in a fat water , by which means the mettallick bodies are indurated by a long decoction . in the philosophical resolving of mettals , and in the creation of that philosophical secret , first is brought forth a clay out of the seed of both parents purged and mixed . . water is the base and root of all moistures , yea , it is moisture it self : from which all moist things receive their denomination , therefore water may be rightly defined the fountain of the moist element , or the spring of moisture , whose property it is to wet by its liquour . but those things are termed humid , which do in themselves according to a less or greater degree , contain a moisture , or a watry liquor . moisture is receivable of all qualities , so bloud and yellow choler are humours , endued with their own heat , although they have their foundation in the element of water . aqua-fortis and the like are empowered with a burning and a fiery nature . the burning water , and many other essences which are extracted from oyls and water , do abound in heat , although the root of them , which is water , be cold , because nature doth first imprint in a moist elemēt various resemblances and signatures of its powers , and doth in it en-root and infuse its principal and choice qualities . moisture is the first subject of nature , upon which her prime care is bestowed , her first charge layed out , by whose liquour it doth dilute and mingle various colours , and indelible tinctures : to it first do the spiritual qualities communicate themselves , in it first do they take up their being and actings . . the lower waters being divided into two , do occupy a double seat , for one part of them brimming the earth , doth lean on it as it were as its proper base , and with the earth makes but one globe : the other part flying upward , doth range up and down the region of the neighbour air , and there making to it self many masqued fancies of bodies , and various figures of several phantasms doth reave hither and thither , over-hanging the lower region . . always there is a great part of the waters that keep above , and being driven to and fro by the caroach of the wind , doth post over divers parts of the air , which was in this manner ordered from the day of the creation , by the enacting of the wisdom of god , that so the uncumbered and plain face of the earth , might be unmasked and fited for the generation of things . for the channels of the sea and rivers were not sufficient to receive the whole waters , but if all should break the confining bars of the heavens , and come tumbling down , it would not onely cover the plain face of the earth , but it may be , overtop the highest mountains . such an enloosening of the cataracts of heaven , we may guess , did occasion the old cataclysm or deluge . . water is not onely sublimated into a vapour by heat alone , neither is it onely bound up in a cloud by cold , but to both the virtues of the sun and the stars do contribute their aids , not onely by multiplying the vigours of the elements , but also by a kind of magnetick virtue , attracting and retaining a moisture much or less , according to their different position , and the diverse figure of heaven : from whence we observe the various ordering of years and times ; for indeed that mass of waters is not kept in , so poized onely by the solidation of cold or the air , but by the powerfull order and regiment of superiour bodies . . lest there might seem to divine justice a want of judgements for the execution of his wrath , he made that ocean which is poized over our heads , to be volatile or flying , and withal brought into his armoury those fiery darts , his thunder-bolts , that so the presumptuous sinners that cannot be won by love , might be wrought about by fear . . they are much out of the way , who do attribute to air moisture in the highest degree , upon this ground , because it is easily kept in within the bounds of another , but hardly within its own ; for this is the property of light and liquid bodies , not of moist , and so doth better agree with fire and heaven , which natures are more rarified , than with water and air : for bodies that are rarified , because they of their own will flow every where , cannot be comprized within their own bounds , and therefore stand in need of another . onely firm and solid bodies are kept in within their own compass and superficies , which cannot be done by those things that are of a subtile nature , because by reason of their thinness they melt and are fluid , and so less consistent . from whence this flows that the air is a body of greater rarity , but not of greater humidity . . the air from it self hath no quality intense and in the highest degree , but sometimes hath them upon loan else-where . the nature of air is a middle nature betwixt things below and above , and so doth with ease assume the qualities of those that border upon it , from whence it happens that its inferiour region , according to the diversity of times , hath a variety of temper , which inconstancy is occasioned by the changes of the neighbouring and thicker bodies of water and earth , whose state is easily altered by heat and cold . . the whole air is the heaven , the floor of the world , natures sieve , through which the virtues and influences of other bodies are transmitted : a middle nature it is that knits all the scattered natures of the universe together : a most thin smoak kindled by the fire of heaven , into a light , as it were an immortal flame : the subject of light , and shade of day and night , impatient of vacuity : the principal transparent : the easiest receiver of almost all qualities and effects , yet the constant retainer of none : a borderer upon the spiritual nature , therefore in the tracts concerning the mysteries of philosophers , it is called by the name of a spirit . . the lower region of the air is like unto the neck or higher part of an alembick , for through it the vapours climbing up , and being brought to the top , receive their condensation from cold , and being resolved into water , fall down by reason of their own weight . so nature through continued distillations by sublimation of the water , by cohobation , or by often drawing off the liquour being often poured on , the body doth rectifie and abound it . in these operations of nature , the earth is the vessel receiving . therefore the region of the air that is nearer to us , being bounded by the region of clouds , as by a vaulted chamber , is of a greater thickness and impurity than those regions above . . the middle region of the air is not that , in which is the gathering of the clouds , from whence are lightenings and thunders , which is onely the higher part of the lower region , and the border of it : but that which is above the clouds is to be stiled the middle region , whither the watry being , by reason of its gravity , cannot reach , yet whither sulphureous exhalations , disburthened of the load of their vapours , do climb up , and there by a motion , either of their own , or anothers , being kindled , burn . such are the flaming meteors of divers sorts , which are viewed in the middle region , whence we may guess , that it abounds with a hot and moist , though not a watry , yet a fat being , which is the food of fire . in this region is much peace and a good temperature , because it is not hurryed with the tempests of any wind , and onely the lighter excrements of the inferiour nature are sucked up hither . . the higher region near the moon is all airy , not fiery , as it hath been taken up , though falsely , in the schools . there is the peaceable habitation of the purest air , and as it borders upon the heavenly region , so it approcheth it in nature , for it is not defiled with the least ●mut of the lower abyss . there is a temperature in the highest , a purity but little inferiour to that of the neighbouring heaven . in this place to fancy a sphear of fire , is the shame of a philosopher , which breaking the laws of nature , would have long ere this ruined the fabrick of the universe . . the fire , as a fourth element of nature , was placed in the highest region of the air , as in its proper sphear , by the chief philosophers , being led by an argument , from order and by conjecture , rather than truth . for let no man fancy any other fire of nature than the celestial light , therefore the blessed philosopher in his genesis , makes no mention of fire , because he had before told of the creation of the light upon the first day , which is the genuine fire of nature , and truly he would else not have omitted fire , if it had been a principle of nature , having specified earth , water , and the fowls of the heavens . . let not any therefore fancy , unless sleeping , a region of fire burning next the moon , for the whole air would not be able to bear so great an abundance of intense fire , but it had long ago fed upon , and ruined the whole fabrick of the world , for whatsoever it falls upon it feeds upon and devours , being the designed ruin of the world and nature . . such a devourer of nature is not lodged as an element of nature , neither above the air , nor below the earth . onely he doth tyrannize in the kingdom of nature , either in the height of the air , or the depths of the earth , or else being kindled , upon the superficies of the earth . therefore lullius , a man of a raised wit , did justly account it amongst the gyants and tyrants of the world . it may also be termed to be an enemy to nature , because whatsoever is destructive to nature , is an adversary of nature . . our common fire is partly natural , partly artificial . it may be man borrowed it for the accommodation of life , and for his necessity , from the celestial , by an unition of the beams of it , and a multiplication of its vigour , or else by attrition or the collision of two bodies , the spirit of god suggesting the project to man . . the sovereign creatour of all things , did place the fiery spirit of a kindly heat in the globe of the sun to inspire light , and an enlivening heat to the rest of the bodies in the universe , wherefore many have thought him to be the heart of the whole fabrick , for from him springs the principle of all generation and life . he that searcheth for any other element of fire in the world , doth shut his own eyes against the sun . . the source therefore of the fire of nature , is seated in the sun , whose heat is always of an equality , and temperate in it self , though it be felt by us either greater or less , according to his appropinquation or distance , or according to his direct or oblique beams , or according to the scituation or nature of places . the sun hath been elevated by most philosophers , as the soul of the world , breathing in motion , and a faculty of generation to nature . . the sun is not the eye of the world , as some ancients termed it , but is the eye of the creatour of the world , by which he doth sensibly view his sensible creatures , by which he conveys to them the sweetly-affecting beams of his love , by which he renders himself viewable to them : for scarcely could a sensible nature have comprehended an insensible creatour , therefore he formed for himself , and us so noble a body roab'd in his own glory , whose rays , that nearest approach divinity , are spirit and life . . from that universal principle of life , all the in-bred heat of elements or mixed beings is derived , which hath gotten to be called by the name of fire , for wheresoever a free heat , a natural motion or life lodges , there nature hath hidden fire , as the principle of them , and the first mover of the elements , by which the sensible elements , or the portions of the world are elementated , and receive their animations , yet doth it cleave close to the womb of the earth , being bound up by the earths density and coldness , exciting an antiperistasis . . that fire of nature which is seated in mixt bodies , hath chosen the radical moisture , as its proper seat , the principal residence of which is in the heart ( although it be diffused through all the parts of the body ) as in the prime organ of life , and the centre of this little world , whence that prince of nature , as commanding from its castle , doth move concordantly all the faculties , and the rest of the organs , and doth in-breathe life to the humours of the mixed being , to the spirits , and finally to the whole elementary mass . and being the sun , and vicegerent of the sun doth act all in this little , that the sun doth in that large world . . as the sun , being in the middest of the rest of the planets , doth enlighten them with his light , replenish them with his influential virtues , beget an harmony of life by his enlivening spirit , so doth the solar spirit in the middle of the elementary nature , giveth it an influential light , and gathers the elements together in the work of generation and doth unite and enliven them . . the first agent in the world is the fire of nature , which being seated in the globe of the sun , doth diffuse that vivifical heat by means of his rays , through all the dominions of nature , working in the seeds a power of activity , and setling in them the principle of motion and action , at the removal of which all motion ceaseth , and also the faculty of life and action . . the heat of nature , and the light of nature , are really one and the same , for they have a continual and uniform effluence from the same fountain , i. the sun , but are distinguished by their office , for the heat is to penetrate into the most inward parts of nature , but light is to manifest , and open the outward parts : the office of heat is to move the occult natures of things , that of light , to set before the eyes sensible accidents : both of these is wrought by the rays of the sun . the sun therefore is the first organ of nature , by whose approach or distance , all the operations of nature are variously governed , intended , or remitted , by means of light and heat . . the second universal agent is that same light ; not so immediately issuing from the fountain , but reflected from solid bodies , inlightened by it as the heavenly , yea , the earth it self : for the light of the sun beating upon those bodies , gives a motion to their dispositions and faculties , and alters them , and diffuseth their several and different virtues by the reflection of his rays , through the whole frame of heaven and of our air : for by those rays , as by so many conveyances , are the various effects of several bodies dispersed every where for the benefit and harmony of nature , which are called by us influences . these are the true and first elements of nature , which because they are spiritual , do communicate themselves to us under some airy , or also some watry nature , to whose good act , as to the roots of the elements , we are beholding for the gift of every birth , and of all life . . love , styled by plato the eldest of the gods , was breath'd into nature , begotten by the divine spirit , and hath the place of a genius in her dispositions . in the first division of the world , betwixt the first brothers , she gave the judgement for the partitions of their families , and after had alwayes the praefecture in generation . . the god of nature did fix the first bond of love in the things of nature , between the first matter and the universal form , the heaven and the earth , light and darkness , plenty and poverty , beauty and deformity . the second degree of love from the first couple , which is as it were the loving embraces of the parents , issued into the elements , which having a fraternal tye to bind them , have divided betwixt them the whole right of nature . the third and last degree , is compleated in mixed bodies , which excites them by the in-born and in-bred sparkles of love , to a propagation and multiplication of their like . the divine love hath appointed this treble love-knot , as a kind of magical tye , that it might deliver it self by traduction into all and every part of his workmanship . love is the base of the universe , the cube of nature , and the fastening bond of things above and below . . let those avaunt therefore , who do attribute the concordant motions of nature to discord ; for nature is peaceable and pleasant in all her workings , yea , she is delightfully tickled in her actings . the very elements of things in their coition are wholly lost in love , that they may knit themselves together by their mutual embraces , and of many be made one . . let the academies stand up , and tell us how the first matter can be the first subject of contraries , and how love can lye amongst the brawlings and jarres of enmity ! or that eager appetite , which the prince of philosophers acknowledgeth residing in the heart of this matter , whereby it doth as earnestly lust for its form , as a man for a woman ? will not those enemies , constituting the seeds of beings and the mixt bodies , by their eternal food , at length force love and concord to yield to their ruine . . they that placed a lust between the matter and the form , and yet an hatred and repugnancy in the matter it self , and in the elements , in making these contraries , have made themselves so : for according to the dictates of their school , the soul in all things generated ( onely man excepted ) is brought forth out of the power and privy virtue of the matter : but how can this be without love ? if the matter radically doth lye under the dissentions of contraries , must not the form , which springs from her very root , feel the same portion ? nay , would it not be stifled by them in its first birth and cradle ? what man therefore that stood right in his wits , would acknowledge the rule of these bandetties , to be chief in the nuptials of love and nature , in the very juncture of the mixture of the elements , and of the information of the matter ? yea , who would expect an uniform , and not a monstrous issue from the heterogeneous seed of opposite parents ? . let therefore the philosopher surcease to place the cause of the alteration of elements , of the corruption and failing of mixt beings in the repugnancy of the elements , but rather lay the fault upon the penurious weakness of the first matter . for in the first chaos . 'twixt moist and drie there was no battel fought , nor any enmitie 'twixt cold and hot . it is indeed the vulgar conceit that there was , whereas onely two , no way contrary , of those four qualities , to wit , cold and moisture , agreed to the female , & the matter , and were in it : the other two , which are heat and drought , which are masculine and formal qualities , came forth out of the part of the informing light . and the earth was not called drie land before the drawing off the waters , and the coming on of the light being , which was first moist and covered with waters . . therefore certainly reason it self doth evidence , that those four qualities , which by the vulgar are accounted repugnant , are not extant in the first matter , unless after information . and lest she might endure some contrariety in its solitude , she had other diseases , to wit , darkness , confusion , deformity , coldness , & an indigested moisture , with an impotency , which are all evidences of a diseas'd and languishing body : therefore being infected from its creation with that corruption , it derived it down to its posterity , lodged in this lowest and weakest region of the elements . therefore it is not set down in genesis of that abyss of darkness , that it was very good , but reserv'd that gracefull elogie for the light , and for the rest that were created . . but who is there that hath the least dram of knowledge , will conceive that this contentious repugnancy did flow from the form into the matter , after the union of the four qualities in the matter being informed ? since it is essential to and the intent of the form , to adde a perfection to the matter , and compleatly to perfect it into an harmony and consent , and a temperament according to its ability . . the first contraries through opposing qualities , were light and darkness ; light hath two qualities heat and drougth ; darkness as many , cold and moisture , wholly opposite each to other , because of their intention . but after those two aged principles of nature came together , and the dark material and female principle was informed by the lightsom , formal and masculine principle , and impregnated by the light , the whole matter of the universe ; and all the regions thereof received this priviledge of light , though distinct in the degrees and differences : for that fiery tincture of the spirit of light left nothing unpierced , and the four qualities also at first being in their highest degree , were brought down to a remission in the informed matter , and so closing sweetly , contracted a fast friendship , and consented to a temperature : and so being made friendly , they were entered into the homogeneous family of the elements , that so there might nothing of repugnancy or enmity lurk in the generation of mixt bodies , whereby the pleasing motion of nature might be disturbed . . neither in nature are those four qualities contrary one to another , but onely divers and unlike one to another , neither do they ruin , but unite into a firm league one with another : so heat and cold in a remiss degree , do amicably agree and commix in one and the same subject , that a middle and temperate quality , to wit , a lukewarness might be produced . but if in the intense degree they couple not without a fight and combat , this proceeds from the excess and tyranny of the intension , which cannot endure two qualities equally heightened and adverse , to be partners and sharers of one and the same sovereignty , but there will fall out a tumult . but indeed nature casteth out intense qualities , as bastards and strangers . . let not therefore any fancy that nature admits fire intense into the family of her elements , for such a fire would be fit for destruction , not generation , would not be according to , but against nature , which avoids violent things , and delights in a temperature , in which is no fighting , no contrariety . for the rule of nature cannot away with the rage of a scorching heat , or a wasting cold , or the distemper of moist and drie , but doth pleasingly lye down in a composed temperature . let not any therefore search for the intense qualities in the elements of things ; he will find them in them either less or more remitted . . he is deceived therefore who says that hot and cold , moist and drie , are simple contraries . for the earth , which by aristotle is laid down as drie in the highest , should always quarrel with the air , which is said by him to be moist in the highest : also water that is cold in the highest , according to his opinion , should be opposite to fire , that is hot in the highest : and this repugnancy would inclose by force every one of the common elements , or every region of the world within the verge of its sphear , and by reason of this antipathie , would destroy all hospitality betwixt them . but we are convinced of the contrary , both by reason and experience . for ditches and all hollow places under the earth , yea , the very bowels and pores of the earth are replenished with air , and the intrinsical moisture of the earth , by which , as with their mothers milk , all vegetables are nourished , is nothing else but an hot and moist air , cleaving close to the earth , and handing it as a nursive and nourishing faculty : the pores of the earth are the dugs , and the airy moisture the milk , by which , she , the mother and nurse of things , doth nourish her off-springs , and give them growth . . they , who settle four elements in as many humours , do grant , that nature being moist , is receiveable , yea , is the subject of four elementary qualities : how then can they hold a contrariety in them , which they place in one and the same subject ? for though those four humours are distinguished by their respective differences , yet have they but one base , one common root to all , to wit , humour : for yellow choller which resembles fire , is no less an humour than flegm , which resembles water : and the same may be said of adust choller and bloud , although they do not absolutely , but comparatively confound the four elements in a moist being . . if there were any repugnancy in the qualities and elements of nature , the greatest would be betwixt hot and cold , and so betwixt water and fire , but the nature of these are not adversary , many generations which are under the waters , do evidence : for wheresoever there is any generation or life , there must be fire , as the nearest intrinsical , efficient , moving and altering cause of the matter for generation : hence men , beasts , and the fowls their being have , and ghastly monsters rowling on a wave ; a fiery vigour to their seeds is given , the homage for their birth is due to heaven . . there fore certainly he will be in the right , who shall acknowledge those four first qualities , inborn and essential to the things themselves , and to their elements , to be apt to a mixture by the direction of nature , and not contrary , for they are as it were four organs or instruments which nature makes use of in the perfecting of her alterations and generations . . nature sets up a potters trade , for she is wholly taken with making her matter circular , these four qualities are as the wheels , by which she doth by degrees and wisely inform her works through a circular and slow motion . . of those four wheels , two , viz , those of moist and drie , are most agreeable to the matter , because nature doth turn and work the matter between these two : those two qualities are nearest the matter , because more subject to be passive , and to a change . but the other two , to wit , of hot and cold , are more of action , because by their turns they alter and change the former ; these are passive , those active , & are as it were the active instruments of nature , working upon her passive matter . . let us therefore cast off that tenent of contraries , as contrary to natures concord , and dash out it with a pen of iron , with the good leave of learning , from the depraved table of philosophy , and let us in the room of it , inscribe the symbole of concord , which nature doth acknowledge of the same standing with her self , by whose help the delightfull copulation of actives with passives is procured in every generation . . those , who according to the flying opinion do stand for four elements contrary each to other , do necessarily introduce a fifth , as the knot or bond-tye of concord , as the peace-maker , otherwise they could not receive any perfect mixture , or any temperature in the work of generation , but without a rudder or a ruler would float a drift through the vast ocean of nature , never able to reach a port , or bring forth a birth : and so would they cheat the common genius of nature of her proper end . . for these four being acknowledged by reason of their repugnant qualities to keep up an eternal war betwixt themselves , cannot be united or appeased in the generation of mixt beings , but rather with their mutual conflict rushing in , will procure an abort , than a birth in nature , unless their contrary actings be composed to a peaceable love by the part of some fifth heavenly and tempering nature , which may introduce a temperature void of hot and cold , drie and moist . . that fifth element , as they call it , or heavenly and incorruptible spirit , springing from the light , motion , and virtue of the heavenly bodies upon these lower beings , and preparing the elements for motion and life , and stopping from ruin particular individuals , as far as their setledness will permit , hath merited the name of the salt nature , the tie of the elements , the spirit of the world , to be given it by the searchers of occult philosophie . . if there were any contrariety between the principles of things , certainly it was between light and darkness , by reason of their opposite qualities , but those qualities were tempered by the coition of both principles , and from the extreams became a middle temper , and such were they when they dislodged from the first , and went into the second principles or elements . the extreams are contrary each to other , onely by reason of the intension of their opposite qualities , but those things that spring from the mixture of these extreams are not ●dverse , because they are of a middle nature , and the ●fflux of the union of the two extreams , to wit , of light and darkness . . that out of the mixture of contraries , to wit , of light and darkness , do not come contraries forth but in a temperature , is plain by that of the kingly prophet , breaking forth into these words of the eternal light , he bowed the heavens and came down , and darkness was under his feet , &c. he made darkness his covert , his pavilion in the middest of it , &c. the very fountain of eternal light , that he might exhibit the brightnes of his infinite glory to mortal eyes , did wrap it up in a cloud and dark mask , and brought the darkness to the light , that he might make of the two extreams a moderate light , and so allay the splendour of so great a light , as was not to be gazed on without the ruin of the spectatour ; yea , philosophers do affirm , the rain-bow that was given by god as a sign and token of a covenant made with man , to be produced out of a mixture of light and darkness , that so that symbole of the temperature of gods wrath , existing out of contraries , might be tempered of various coherent and friendly colours . . those that have delivered that the earth , water , air and fire , in their sphears are distinct elements of the world , and are turned each into other , by mutual reciprocation , did but slightly look into the depths of nature ; for it is more safe to call them the compleating parts of nature , or the shops of the elements : for the elements of the world do not lye under our view or senses , as separated in their proper regions , but do lye hid and keep close in their wombs , till they come together in the generation of mixt bodies , and make up a body . but those parts of the world , as so far mutually different , can never have a conversion in them , neither can that one common quality , whereby those natures are linked together , beget such a change , that out of things of a diverse , should be formed a like nature , yea , that they should be turned into the same . . if those four elements asserted by them , do change and barter their rooms , natures and offices , all the compact frame of the world , devoted to a chance and motion , would be in a perpetual fluctuation , which we know is established by god in a certain and constant order and scite , and distinction of parts : for earth will quickly be made water , water air , air fire , and so backward , and by this the centre shall run out to circumference , and the circumference run into the centre , the farthest and the middle parts of the world , shall of their own accord remove out of their places , that so after a long time the order of nature shall be inverted , whilest the top and the bottom , and the bottom and the top change places , and clash together . he who doth fancy this so fair composure of a world , doth not deserve to have so fine a piece termed a world , but a chaos , an abyss , which nature , a friend to order , doth absolutely detest . . they which do say that those extream bodies of the lower world , earth and fire , ( supposing , not granting a sphear of fire ) are turned into each other , do wrong themselves and truth too . for their distant and repugnant natures do disagree from such a change , for the heightened cold , thickness , and gravity of the earth are so opposite to the same degree or heat , subtility , and levity in fire , that they can never be brought to change . besides , the earth , a fixed body , will not yield to fire , but slighteth its virtue , if we may believe the opinions of chymists and common experience , neither doth any thing flie out from it , but a fat and warry humour , both of them not natural to the earth : but if any thing is to be turned into elementary fire , it must necessarily be light and volatile , that it may be translated into its orb and nature . the earth therefore being most weighty , and so the centre of all , being most fixt , and so least volatile , how can it be turned into fire , and be carried up into the sphear of fire , or how can fre , the highest and lightest of all , be beaten down to be essentially united with the earth , contrary to the laws of nature ? it were a more easie conversion of water and fire , because they are nearer by one degree than earth and fire . they that believed , the exhalations from the region of the earth drawn up into the air , and because kindled there , to be earthie , and converted into the element of fire , are far out of the way of truth , for they are not earthie , but rather airie natures : for our air being moist , through the contagion of water lying in the drie bosom of the earth , gather a fatness , and by the consortship of the earth , doth temper the moist with the drie , but when it exhales through the pores and crevises of the earth being drawn by heat , or else the abundance of the matter forcing out , it breaks not forth out of its prison without a noise & crack , whence proceed earth-quakes and openings not without much ruin ; that exhalation , got loose , doth flie up into the region proper to light bodies , and there is set on fire , being digested by its errant motion and heat , more fully into a sulphureous matter . therefore that matter is not truly earthie , since it is neither ponderous nor cold , but because it is made fat and combustible by the concourse of hot , drie , and moist ; it may more properly be called the accidental food of fire , than the fire of nature , or the elementarie fire . that is a bastard , a spurious generation , which for that very reason ought not to have been placed amongst the natures , or been called by the names of elements ; therefore these firings are rightly called by aristotle , imperfectly-mixed things . the same we must conceive of the smoke of combustibles : for smoke being unctious , doth quickly take fire , which is nothing else but smoke kindled . fire feeds upon fat and unctious matter , but the fat moisture of the air is contempered with drought , whence we often may see a sulfureous matter , extrinsecally drie and terminated with drought , as our ordinarie sulfur , gun-powder , and the like ; which though they seem to be outwardly drie , do close within them a fat moisture , and upon the firing are resolved into it . and truly they slip to purpose , that have taken an opinion , seeing stones and heavie bodies sometimes generated in the air , and shot down thence by lightnings , thunders , and breaking of the clouds , that the fire turns to a stone , or is converted into earth , or have a conceit , that the earth is carried up thither . this is done far otherwise ; for that hardened matter was never fire or earth , nor proceeded from the orb of fire ( if there be any ) or from the bodie of the earth , but an unctious and viscous humour , in a manner clayish , shut up in a cloud as in a fornace , is so hardened and decocted , as an earthen vessel by the heat of the burning exhalations , that it turns a stone : hence proceed those darted thunder-bolts . such meteors as these are the wens , weaknesses , and diseases of nature , not elements . in the same , though after a slower manner , is the stone generated in the bodie out of flegm in the reins or bladder . for the microcosm hath also his meteors . the fire of nature is far different from our artificial or accidental fire . the fire of nature is double , either universal and particular , or individual . the universal is diffused through all the parts of the universe , doth sweetly excite and move the propensive virtues of the celestial bodies , doth impregnate and supply with engendering seed this globe of ours , designed for the generation of things ; doth infuse virtues into the seeds ; doth untwist the intangled power of nature ; mingles the elements ; informs the matter ; and finally doth unlock the secret of nature : but the fountain of it is in the sun , who as the heart of the world doth stream forth his enlivening heat as his love through all regions . but the particular fire of nature , is in-born and in-bred in every mixed bodie , and individual , which flows as a rivulet from that general , and doth work all things in this microcosm or little world man , according to an analogie with the sun in the macrocosm or greater world . but who is there that would not stile our common fire , being an opposite of all generation , living onely upon prey , subsisting upon the ruins of other beings , the destruction of life , deputing all things to ashes , rather a foe than a friend to nature , its enemie , not its inmate ; and rather the ruin than the raising of life ? but those fires that are bred in the airie region , are rather engendred by chance , than by any intention of nature . neither are those two bodies of the earth and water , situated next one to the other , convertible each into the other , but onely by reason of their neighbourhood are mingled together ; so that the water washeth the earth , and the earth thickens the water ; and hence is made clay , being a bodie of neither , but a middle betwixt both ; which if resolved by the force of fire , will separate it self into both these natures . the water flying out , the earth settles : neither will there be any conversion of each into the other , for that cannot be effected by that single common qualitie of cold , since the driness and moisture are not less powerful to resist , than the mutual consent of cold can bring them to a conversion . besides the driness and fixation of the earth , are quite opposite to the moist and volatile nature of the water , so there is but one qualitie agreeing to an alteration , and many disagreeings , which will prevail in the combate . besides , here is the help of nature always readie to conserve it self , and doth never incline , unless upon force and conquest to its ruin or change . we may guess the whole globe of the earth , not to be of a less settled nature than the heaven , the moon , or the stars ; for it , if it be the centre of the world , as it is generally received , then certainly the constancie is not less necessary to it than to the rest of the bodies of the world . besides the earth is the same without any essential immutation of what it was from the beginning , and what it will be to the end of ages . but if it did suffer any notable detriment by the universal deluge in the general , or any accidental in particular , as by some chasme , or by the breakings in of rivers , or the sea ; this falls out by the supream order of him that doth change at list , the laws of the whole and every region : or by the discordant harmonie of the world , or by some disease of some distempered nature , rather than by any propensiveness or viciousness of the earth . for all the bodies of the universe do lie under their burdens and diseases , although they be diversified according to the disagreement of nature , and difference of perfection , yet the accidents do not change the nature and constancie of them in respect of the whole . absolute constancie and impassibilitie do onely suit to god alone : but the heaven , water , earth , and the rest of the bodies of the universe shall stand firm , in regard of their essence to the designed period of their age . if any one of those four natures have a propensitie to conversion , it will be strongest in the mean qualities ; for water and air are joyned in greater affinitie between themselves than with the rest , or the others amongst themselves . for they seem not to differ so much in their qualities , as in the intension and remission of them , not so much naturally as accidentally . for since water doth by a right of nature challenge to it self moisture and coldness , it doth also communicate them to the lower region of the air by way of commerce , ( for air obtains no proper qualitie almost besides the highest tenuitie , yet capable of receiving the rest , therefore is it of an heavenly nature , being of it self most temperate , and not addict to any proper qualitie , doth readily receive and-despence the dispositions , influences , and virtues of the heavenly bodies . ) densitie and raritie , which in a remiss degree are of kin , seem to make the principal difference between water and our air ; for which reason god is said in genesis , to have separated the waters from the waters ; as if by reason of the unity of their nature , it seemed more truely to be a division of their situation , than a mutation in respect of their essence . yet these bordering natures , do not entertain any true and essential reciprocation , but onely according to some respect , not altogether changed , but after some manner ▪ and this change is acted in the lower region of the air , which is bound in by the cover of the clouds , and reacheth not the middle , much less the highest region . water being rarified into a vapour flies up , and is rather raised then turned into air ; and that vapour condensed doth resolve , and fall down again . the ancients , being led by the legerdemain of sence , more than the light of reason , conceived this circulation , and returning into it self of one and the same nature , to be the turning of nature into another : but it is found to be otherwise by those that have and use a sharp insight into the depths of nature . he is also deceived that shall call the air simply a thin vapour , because a vapour is a middle and imperfect bodie betwixt the two waters , those above , and these below , betwixt our water and air , yet it is neither of them , because although it rarifie , yet will it never be heightened to the great degree of the nobilitie of the air . it may be made a spurious but never a pure air : neither will the refined nature of the air be so depressed and fall from its puritie ▪ as to thicken into a vapour , cloud , or water . for the right of nature never got that first separation of the waters , which was really and actually done by that architect spirit , and that the established bounds of the parts of the world , which god hath sealed with an indelible signature , should either be blurred or removed by any new confusion . but those that dive deeper into things , will acknowledge the earth to be the womb of the world , the vessel of generation , the mother of a multiplied , and almost numberless issue , which being rescued in the beginning of the creation from the power of the covering waters , and priviledged to it self , was made and remained drie land ; and her bodie being condensed , sunk to the foundation and the centre of the whole , and spread out her lap as a parent to all vegetables , and all other creatures ; yet did she want moisture , whereby she might be made apt for a fruitful generation . gods providence set out a remedie for this exigence : therefore from the beginning was the water made volatile , that so it might be carried up in vapours , which being frozen by cold in this cloud , might by heat be thawed again into waters . by this master-piece of divine providence , was this exigence of the earth supplied , and that driness , which threatened barrenness , was tempered with a large moisture , and the womb of our mother conceived . therefore onely water hath the circulation , to the intent that it might moisten the bosom of the earth , or more truly it is distilled in the lower region of the air as in its alembick ; that so by often pouring in , and reiterated distillations , it being abounded , and having gotten virtues both from above and below , and endued with that celestial nectar , it might more effectually soften the bosom of the earth , and endue it with a prolifical virtue . the chief worker of all , who maketh use of the art of nature , hath added nothing superfluous to his work , nor left any thing defective in it . but the water being the menstruum of the world , doth cherish and contain in it the seeds of things and their elements ; but she having this circulation , the true and genuine elements of things which are in the earth , as in the matrix and vessel of generation ; and in the water , as in the menstruum , are also whirled about . in the vapour therefore , are the elements of the earth , the water , and the air , & have their sublimation , and exuberation with it . they are not the bodies of earth , water , and air , which have their proper sphears , and constitute the several regions of the world , but they are the very spiritual elements of nature , which lye hid and inhabit in them , out of which many bodies , as stones may be generated and excocted in the air . for where all the elements well mixt , do meet , as they do in a vapour , there bodies may be generated ; but when they find not a convenient matrix , as in the air , there are ingendered imperfect mixtures , not by reason of any fault in the mixture , but in the matrix . . the water being seated as middle , betwixt the earth and the air , doth trouble both it by its flowing , and always moving inconstancy , infesting the air with a black soote , and noisom vapours , and often drowning the earth by flouds ; causing tempests in the air , ruines to the earth , and corruption to both ; and it doth assault the region of the one with its levity , and of the other with its gravity ; and doth cross the order of nature , and the nature of times by its defect or excess , yea , doth shake all her borderers with her terrible claps and tumultuous ragings . her nature being altogether female ▪ the supream creatour seems to have bestowed her on the world in the nature of a woman , or a necessary evil , even so doth she arrogate all things as subject to her , and turns those things that were given her for a general good , to a publick ruin . finally , it is the scourge of divine justice , revenging nemeses , which being designed to the vengeance of sin , doth break out to punish , and sets the hopes and wealth of many the very roots of pride , under several shapes of judgements , the scoff and blast of the world . . the universal natures , the more thick they are , the more impure , the more endued with tenuity ; the more purity . the earth , because more thick than water , therefore is less noble , and so water than air ; and air than heaven : and so the highest region of the heavens is the most noble , because it is most subtile . for it is an undoubted truth , that spiritual natures are more excellent than corporeal , and the more bordering upon the spiritual natures , the more they draw nigh to perfection . . the foundation of generation and corruption is in moisture , for in both the travails of nature , moisture , of all the elements , is the first patient , receiving the first seal of the form . the natural spirits are easily united with it , because flowing from it , do lightly return to it , because the root of them , in that , and by that , are the rest of the elements mixed . the moist element hath its circulation no less in mixed and individual bodies , than in the world , both in the work of generation and of nutrition , for it was natures pleasure , that both these works should be performed by the same instruments of condensation and rarefaction , and by the same means , to wit , spirits . . the earth is the vessel of generation , water the menstruum of nature , containing in it the formal and seminal virtues , which it borrows from the sun , the male and the formal universal principle ; from him is derived into all things the influence of the fire of nature , and of formal spirits , in which are all things necessary for generation , the in-bred heat being wrapt up in the moist : therefore hippocrates did rightly affirm , that these two elements , fire and water , could do all , contained all things in them : for from them do issue two masculine qualities of hot and drie , from the other two more of cold and moist , being the female qualities , which so concurring and mixing , perfect the generation of mixed bodies . over those two principal elements , the two greater lights were set , the sun the authour of fire , and the moon the lady of moisture . . nature perfects the circulation of the volatile element , by a three-fold action or instrument , by sublimation , demission or refusion , and by decoction , which stand in need of a divers temperament . so doth the rightly ordered intention of nature , wandering through various motions , directeth her interrupted actions to their designed end , and attaineth the same mark , though it trades through divers wayes . sublimation is the conversion of a moist and a ponderous nature , into a light , or the exhalation of it into a vapour . the end and benefit of it is three-fold : first , that a gross and impure body might be mundefied by attenuation , and might by degrees be drawn off the dregs ; then that by sublimation it might gain the higher virtues , which continually flow down . lastly , that by such an evacuation the earth might be disburthened of its superfluous and loading humours , which seizing upon its passages , do hinder the action of the heat , and the free pass of the natural spirits , yea , do violently choak them . this drawing away of the superfluous moisture , takes away the cause of obstructions , and gives ease to the squeazy stomach of the earth , and makes it more fit for digestion . . but the moisture is sublimated by the impulsive operation of heat . for nature useth her fire as its proper instrument for rarefaction of moist bodies . therefore the vapours that generates clouds & rain , are most frequently drawn up in the fall and spring , because then the womb of the earth doth more abound with hot and moist ; now moisture is the material , and heat the efficient cause of exhalations . nature doth shew a kind of intense heat in sublimation , whilest it is bound in within the terms and latitude of temperature . . demission is the second wheel of nature ; in the work of circulation is the returning of the spirituous vapour into a gross and watry body : or the refusion of a rarefied and sublimated humour , being again condensed , and its descent into earth , that it may dilute it of its exuberant liquour , and suck it up by a sweet and celestial draught . . nature doth intend three things by irrigation . first , that it might not pour out , but by degrees distil its abundant humour , lest there fall out a gulf , and by the abundance of water , the passage for the vivifical spirit in the bowels of the earth be dammed up , and the intrinsecal heat of the earth be extinguished , for that wise and righteous governess doth dispense all her benefits in number , weight and measure . secondly , that it might distribute the humour by divers drops , and by a various manner , to wit , a rain sometimes larger , sometimes less , sometimes a dew , sometimes a hoar frost , sometimes pouring out a greater , sometimes a less plenty , that so it might water the earth according to its appetite or necessity , thirsting for more or less . thirdly , that these irrigations or waterings may be not continual , but by turns and betwixt other works ; for the sun doth in its course succeed the showers , and the showers in theirs the sun , the day the night , and the night the day . . the lightest cold or the departing heat , doth unloose and make fit to fall those vapours that are brought up into the middle region , and there frozen . for an immoderate heat doth dissipate and hinders their condensation , and an intense heat doth so knit and freeze them , that they cannot produce a humour that may be fit to fall down . . the last wheel or action of the circulation of nature , is decoction , which is nothing else but the digestion , ripening , and conversion into aliment of a crude humour instilled on the bosom of the earth . this seemeth to be the end and the scope of the others , because it is the release of their labour , and a receiving of the food , attained by the former labours . for that crude humour , by force of that internal heat , is chewed , concocted , and digested by it , being as it were without motion and in a trance , silently and without noise , moving that secret fire as the proper instrument of nature , that it may turn that crude liquour tempered with driness into a food . this is the compleat circle of nature , which she rowls round by various degrees of labour and heat . these three operations of nature are so knit together , and have such a relation each to the other , that the beginning of the one is the end of the other , and according to natures intention , they do in a necessary order succeed one another by turns . and the orders of these vicistitudes , are so interwoven and linkt together , as that combining to the good of the whole , they do in their operations prove serviceable each to other . yet nature is forcedly sometimes drawn out of her bounds and verges , and ranges in an uncertain path , especially in the guidance of the moist element , whose orders being interrupted do deceive , and they do easily as well as suffer wrong , by reason of the inconstancy of its volatile and flitting nature , as also by reason of the various disposition of the superiour bodies , which do bend these things below , especially moisture , and draw them from their setled track , according to the beck of the sovereign moderatour , who doth use them as organs and instruments to the motion of the frame of the universe . hence is raised the deceitfull and inconstant temperature of this our mansion , and the changed seasons of the year . so doth the womb of the earth , being diversly affected , bring forth either more plentifully or more sparingly , generous or castling births . so doth the bordering air being either pure or impure , produce either health or sickness , the moist nature rowling and tossing all things amongst us . the rule of our heavens is uncertain and deceitful to us , because things below receive their orders from things above , whose natures and affections are for the most part unknown to us , yet let the philosopher set always before his eyes the intention rather than the action of nature , the order rather than the disturbance of the order . we may observe the volubility or flittingness of the moist nature , not onely in the general harmony of the world , but also in the particular of mixed beings . for they are generated by the revolution of moisture , they are nourished and grow by drying , moistening , and digesting ; wherefore those three operations of nature are resembled to food , drink , and sleep , because meat answers to driness , drink to moisture , and sleep to concoction . lest man should dream fancies to himself , glory in divers priviledges , assume to himself as proper onely to him the name of microcosm , or the worlds lesser draught , because there are discernable in his material workmanship , an analogie of all the natural motions of the microcosm , or the larger volume of the world , let him consider that every creature , even a worm , that every plant , even the weed of the sea , is a lesser world , having in it an epitome of the greater . therefore let man seek for a world out of himself , and he shall find it every where , for there is one and the same first copy of all creatures , out of which were made infinite worlds of the same matter , yet in form differenced . let therefore man share humility and lowliness of spirit , and attribute to god glory and honour . the inferiour natures are leavened by the superiour : but the water not enduring delay , doth hast to meet the operations of the heavens , for the air , giving way to the vapour that flies up to it , receives it to lodge in the region of the clouds , as in a large hall , but ere it comes thither , its body being in a manner spiritualized , the moist being is divested of its ponderous nature , that so it might by this addition of agility , the sooner compass its desire , and enjoy the priviledge of an ambiguous nature . in the mean time the sun , the prince of the celestial quire , and the rest of the superiour natures , taking care of the inferiour , do instil by continual breathings enlivening spirits , as so many trilling rivulets from their most clear and pure fountains : but the vapours being thin , and so swimming in the air , or else bound up into a cloud , do most eagerly suck in in that spiritual nectar , and attract it to them by a magnetick virtue , and having received it , they grow big , and being impregnated and quickened with that ingendering seed , as being delivered of their burden , do freely fall down back into the lap of the earth in some dew , hoar frost , rain , or some other nature ; and this mother of the elements doth receive into her womb the returning moisture , and being quickened by this heavenly seed , sends forth in her due time innumerable issues , according to divers degrees , more or less generous , according to the goodness of the seed , or the disposition of the womb : and the inferiour waters also are made partakers of the benevolence of the superiour and celestial , because she goes with the earth to the making up of one and the same globe , and so they receive joynt and common benefits . but by the nature of water is the fermentation of the rest of the elements . but this ferment or leaven is a vivifical spirit , flowing down from the superiour natures upon these inferiour , without which the earth would be again void and empty . for it is the seed of life , without which neither man , nor any creature , nor any growing thing could enjoy the benefit of a generation or life ; for man lives not by bread alone , but especially by that heavenly food by air , to wit , by such a spirit so breathed in , and fermented . the three material elements being remote in the composition of things , do onely obey god and nature , and come not under the laws of art , or of humane invention : but there are three others that issue from the copulation of these , which being extracted by resolution , do sufficiently shew that they are the nearest in the composition of mixt beings , to wit , salt , sulphur , and mercury . and so it is manifested , that there is a trinity of elements , and a signature of the universal nature . these three last elements are the issue of a three-fold copulation of the three former , mercury of the mixture of earth and water , sulphur of the copulation of earth and air , salt produced out of the condensation of air and water , and there can be no more combinations of them named . the fire of nature is in all of them as their formal principle , the virtue of the celestial bodies contributing their influence and co-operation . neither are these latter produced out of any copulation of the former bodies , for mercury comes forth of an unctious earth and clear water well diluted and mixt . sulphur is generated of the most subtile and driest earth coupled with the moist air ; finally salt is congealed of salt and thick water , and crude air . it may be lawfull to affirm that democritus his opinion , that all bodies were composed out of atoms , is not far distant from truth : for both reason and experience do vindicate him from biting tongues , for the knowing philosopher would not wholly conceal , but would unfold in an obscure and dark term , the mixture of the elements , which that it might be agreeable to the intention of nature , must necessarily be done by the smallest , and by actually indivisible beings : other wise the elements could not combine into a continuous & natural body . experience teacheth us in the artifical resolution & composition of mixt beings , which are tryed by distillations , that the perfect mixtion of two or more bodies , is not done but in a subtile vapour . but nature doth make her mixtions far more subtile , and as it were spiritual , which we may safely believe was the opinion of democritus : for the grosseness of bodies is an impediment to mixtion , therefore the more any thing is attenuated , the more apt and fitted it is for mixtion . the three-fold degree of existence in mixt beings , doth offer to us three supream kinds of mixt beings , to wit , of minerals , vegetables , and of animal beings . natures law hath appointed a being for minerals in the earth , for vegetables in the earth and the water , for animals in the earth , water , and air ; yet to all the air is the principal food and foster of life . minerals , are thought simply not to have an existence or a life , although metals from minerals may be said to be endowed with a principal life , both because in their generation there is a kind of a copulation , and a commixiton of a double seed , male and female , viz. sulphure and mercurie , which two , by a long and multiplied circulation , are turned and purged , and being seasoned with the salt of nature , and fermented by it , and being perfectly mixed in a most subtile vapour , are formed into a clay or soft mass , the spirit of sulphure by degrees closing in the mercurie , at length that mass doth grow hard , and is confirmed to a metallick body . as also , because perfect mettals , especially do contain in them a principle of life , to wit , in-set fire infused from heaven , which being dulled by being bound in with the hard outside of the mettal , lies hid as void of motion , and as an enchanted treasure , till getting libertie by philosophical solution , and the subtile artifice of the work-man , it doth powerfully display its refined spirit and celestial soul , by a motion of vegetation , & in the issue , heightned to the sudden perfection of art & nature vegetables also are invested with a vegetative soul or spirit , they grow by a vegetative motion , and multiply● , yet want an animal sence and motion . their seeds are of an hermaphroditical nature , for every particular grain doth contain in it a fruitfull seed without copulation or mixture of a double seed , although in every kind , almost , of vegetables , experience sheweth , there are both sexes to be found . god also hath wrapt up in the seeds of vegetables , a secret spirit , the authour of generation ennobled with a special character , which is wholly celestial , and a ray of the heavenly light , void of corruption , in which is preserved the specifical form under the bodie of every individual subsistance , which being through corruption resolved & lost , that immortal spirit being called out by the vivifical and homogeneal heat of the sun , doth rise up in a new stalk , and doth bring into it the form of the fo●mer . animals , besides their existence and faculty of vegetation , do exceed in a sensitive soul , which is in them the principle of life and motion . therefore an animal , seated in the highest degree of things below , doth compleat the work of nature in her elementary kingdom , doth live properly , generate properly , and in it hath nature truly distinguished each sex , that from two , a third , to wit , their issue might be produced . so in the more perfect beings the most perfect symbole of the trinity is most apparent . man , the prince of all creatures , and of the lower world , is accounted the summary of universal nature : for his soul is an immortal ray of the divine light , his body is a beautified composure of the elements . the inward and unperceiveable faculties of the sense , by which man doth comprehend all things obvious , are altogether celestial , and as it were stars , giving the influence of knowledge of things ; the motions and perturbations of the mind , are as it were the winds & tempests , lightenings and thunders ; the meteors , which break forth in the aerial region of the spirit , do trouble the heart and the bloud . therefore was man deservedly called a microcosm , and the accomplisht draught of the universe . but not onely man , but even every living creature , yea , every plant is a microcosm . so is every grain or seed a chaos , in which are the seeds of the whole world compendiously bound up , out of which in its season a little world will spring . whatsoever beings of natnre have a perfect mixture and life , they have a body , spirit , and soul . the body is made of clay , in which are all things necessary for the matter of generation , for it is most agreeable to reason , that bodies should be made of two corporeal elements especially , viz. earth and water . the spirit is a small portion of the purest air , or the heaven , a middle nature betwixt the body and the soul , the knot and bond of both , the case of the soul , and the conduit of the more subtile and spiritual parts of the body . the soul or form of a mixt body , is a spark of the fire of nature , an undiscernable ray of celestial light , brought into act from the power of the seed , by the motion of generation , bound to an elementary body by the mediation of the spirit , giving its individual being to the mixt body , the nearest principle and the efficient cause of life . it acts according to the disposed matter , and the qualities of the organs . the nature or from of the soul , because it is altogether full of light in living creatures especially , hath so great a distance from the dark and earthy matter of bodies , that this is wholly irrational in respect of that , and this unproportionably more noble , and therefore is fastened by that strictest tye which nature makes use of in her works to the body , by reason of the disconveniency and distance , unless the conjunction and knot had been made by the virtue and efficacy of a peculiar and powerfull mean , therefore did the provident creatour assign a subtile mean , which is the aetherial spirit , which receives and retains the begotten from , and is the tye of it to the body , communicating in its nature with both . these things are to be conceived to be spoken of the celestial soul of natural things , not of the super-celestial and divine soul of man , which notwithstanding is according to the good pleasure of the creatour , brought into a consortship with the body of man by natural mediums . the specifical forms from the first day of the creation , were imprinted in the first individual and particular persons , by the character of the idaeal copie , and that diviue and indelible impress was according to the direction of the creatour , by the way of generation traduced to posterity , that so by the perpetual succession of particular individual natures , the priviledge of immortality might be continued in the kind . it cannot , nor must be conceived , that forms do generate in the matter their like , for to generate is the alone property of bodies , but by an harmonious motion of their organs , they do by them dispose the seminal matter for generation , and shut up in it a ray of light , or a secret spark of life , as a treasure : this is the office and priviledge of the form , as also to imprint its own specifical character on that vivifical spirit , wrapt up close in the seed , which in its set season , doth in the work of generation by the engendering heat , display it self into a soul , whether vegetative or animal , so that what was a formal and hidden spirit in the seed , is now a form in the mixt body . so that occult thing that was closed in the bosom of nature , is now made manifest , and brought forth from a power to an act . the form issues not forth onely out of the power and virtue of the seed , because there is an influence of celestial virtues in the generations of beings , which do heighten the efficacies of the matter , do multiply them , and as it were midwife it to groaning nature , yea , they do get into , and mixe themselves with , and bring in auxiliary strength to the formal and seminal spirit that is in the matter , which is also by its original , celestial . there do not onely meet in the generation of every mixt being , the corporeal elements , but also all the virtues , all the powers of nature in general , and these do contribute something of their own ; so are the parts of the universe bound up together , that they have an unanimous combination for life , and couple by a mutual affection . the natural forms of things though they are potentially in the seeds , yet are they neither of , nor generated by the substance of the lower elements , for they have their rise from a more noble spring , their original is from heaven , for their father is the sun , the heavenly nature the bond whereby these matters are knit together . the specifical forms of mixt beings have within themselves closed a dark kind of knowledge of their original , and are carried up by their own strength , and by a secret motion , like unto waters , to the height of their fountain head . so the soul of man being derived from the divine spring of the uncreated light , is reflected to the same by the sharp sight of his mind , and by the soaring contemplations of his soul , but the forms of other living creatures being taken out of the privy treasury of the heavens and the sun , do by the instinct of nature , and by a weak kind of reminiscency , glance back thither . hence we may observe the frequent prognosticks of several creatures concerning the courses of the sun , and the changes of the heavens . but the forms of vegetables , being for the most part airy and inspired from the lowest region of our air , therefore they are not able to extend or reach forth their power , or faculties beyond it , they do , according to their ability , lift up their heads into the air , as willing to visit their countrey , but they are stopped so , as that they are not able to pass the narrow confines of their bodies , wanting the sense and life of a soul , because there is so little of the suns virtue in them , as will not carry them above the motion of a vegetation . for in the order of creation , the vegetables were first before the sun , wherefore creatures are not equally indebted to him for their originals , and the aged principles of their life , but must acknowledge them received from the lightsom air , as a nearer agent . for the disposition of their matter was adjudged by nature as too weak to receive so sublime a form . but for stones , since they are not so much generated out of a true mixture of the elements , as from a concourse of earth and water , by an external force of heat and cold , they are decocted as an earthen work or vessel , therefore they are altogether senseless , having borrowed a feeble form from the dark and cold nature of the earth and water . concerning precious stones and gems , we must conceive otherwise , for they derive their forms from the chrystal fouutains of the heavens and the sun , and their bodies are the purest drops of a refined dew , engendered by celestial influences , and as it were the congealed tears of of heaven , whence they possess and contain many sublime virtues . but the matter of metals , because it is watry and earthy , and most compacted , by reason of the principal & subtile commixtion of weighty elements , is therefore heavy and exceedingly ponderous , and of it self capable of no motion : but because it is sublimated and mundefied by the wonderfull artifice of nature , in an earthy and stony matrix , as in a limbick , and its mixture is compleated in a most thin vapour , by reiterated distillations , that by reason of its exceeding subtility and exuberancy , the influential helps of the sun and the heavens , get in and mix with it , especially in the generation of perfect mettals ; for this cause , though they fetch their bodies from water and earth , yet nature performing the office of workman , doth so ingeniously make up the bodies , especially of a perfect mettal , that it delivers them to the heavenly deities , as those that deserve to be informed with the most eminent form . it is a work of long travail , but an absolute one , & heightned to the utmost of natures actings , in which heaven and earth seem rather to copulate , than to consent . but the formal spirits of mettals being bound up in a hard cover , do stick immoveable , till released of their bands by philosophical fire , they do produce by their heavenly seed in their matter , that noble son of the sun , and at length that quint-essence of admirable virtue , in which the heavens seem to lodge with , and come down to us . it was provided by the decree of the supream creatour , that a nature more noble should not degenerate into one less noble , or that one more eminent , into a nature that is more base , or that it should , abjuring its native priviledge of birth-right , come under a servile vassalage . superiour beings are coupled with these below , and those of greater power do communicate themselves with those of a less , that they may inform and compleat them by their emissary spirits , which notwithstanding in this do no way derogate from their stock or kind . nay , when they work themselves into the seeds of things , or also into mixed beings , they subject not themselves to a bondage , but do attain a new honour and priviledged power . for every mixt being of whatsoever kind it is , is a kind of an empire , yea the whole world , who hath a spiritual form of her own to rule her , whose office it is to have dominion over the organs and faculties of nature , yea over the whole frame , so that that , which being void and without distinction , did drift it rowling hither and thither in the vast ocean of nature , is now called to an empire . the formal act of the first matter , as also of the elements , doth inform nothing besides the verie principles of nature , therefore the specifical form doth constitute a perfect mixt being , neither is it to be thought to contain any more forms , since the very elements in their mixtion , have the charge of the fashioning , not of the informing of the bodie . it is most probable , that the virtue of multiplication , which lyes in the seeds of beings , doth not flow from the elementary matter as its efficient cause , but from a celestial form : for to multiply , is the most natural and proper action of light , for from one ray are almost an infinite number darted forth ; from whence it proceeds , that the sun , who is the fountain of immortal light , is also in nature the first efficient cause of generation and multiplication : that therefore every form receives a natural power of multiplication from the celestial light , is prov'd by this weighty argument , because it is lightfull and furnished with its native endowments , ergo multiplying ; it is lightfull , because it doth enlighten with its rays the sensitive and imaginative faculties in creatures , that so out of that double faculty , springs a double apprehension & knowledge of things ; an external by the senses , an internal by imagination ; but all knowledge is a light , as all ignorance is a darkness : but there peeps up some enlightening and lightsomness , when there is an apprehension of the images of things , and when that , which lay unknown in the dark , is now manifested by a light of knowledge , for it is onely by the good office of light , that obscure things receive a revelation . god did adde to man a third light , to wit , his understanding , by the help of which he attains by their causes , a far more perfect way of knowledge . all these things are produced by the operation of light , and of a perspicuity flowing out of an enlightened soul . this last action of light is onely proper to man , the two former are shared with beasts as well as by him , for their souls are also partakers of celestial light . therefore reason doth convince , that the virtue of multiplication in the individual beings of animals and vegetables , doth proceed from the souls multiplication of light , and that some rays of it are included in the seed with the aetherial spirit , until at length they are set upon the rising of the sun of life . light and darkness are the principles of life and death , for the rays of light are the forms of mixt beings , their bodies a dark abyss . by light all things live , yea light is life ; but those that loose their life , loose their light , and are hurried into their former darkness , in which they lay close and hidden , before they were drawn to light by the fatal wheel of predestination . the specifical forms of animals , as also of vegetables , are rational , though not after the manner of men , but after a property of their own , according to the virtues and impress of their nature . for they have their vital endowments , their cognizances , knowledge , and their predestinations . the vital endowments of vegetables , are an endeavour of generating the like , the multiplying virtues , nutritive , augmenting , motive and sensitive , and the like . but their knowledge is experienced by their wise fore-knowledge of times , their strict observation of change , as of the orders of nature , in a variety agreeable to the motion of the sun and heaven , in the fastening the roots , the erecting the stalk , spreading the branches , in the opening the leaves and the flowers , in the forming the fruit , in their beautifying , in their ripening , in the transmutations of elements into aliments , in the inspiring of a vivifical virtue into the seeds ; lastly , in constituting a various difference of nature and parts , according to the benign or malign concurrence of the sun or soil . that the souls of bruits are endowed with knowledge , is sufficiently , by their copulations and generations upon set times , their just distributions in the forming and nourishing of the parts of the individual beings , the distinct offices of those parts free from any confusion , the various motions of their souls , the nimble faculties of their senses , the secret spirits , harmoniously moving the members as organs , their proneness to discipline , their obsequious reverence to their masters , the presaging instinct of things to come ; in most a devout worship , an art in getting their provision , in choice of their raunges , providing their fence , their prudence in the avoiding dangers , and the rest actions so agreeable to knowledge and reason , bestowed upon them by nature . but nature in every individual , is nothing else but the form it self , which is the principle of motion , and rest of action , and life to it , in which it is , to which is committed the charge , direction and conservation of its body , as a ship to a pilot. but who will deny the certain predestination of times for the birth of things , unless he fancy a confusion and disorder in the nature of the universe , for she draws forth all those things out of her bosom , according to setled and fore-appointed order , for she had a prescript from her maker for the law of order , and the times of production ; their quickening , birth , life and death have their set times , and do fulfil their designed seasons ; those things that either this or that year receive their being , or return to darkness , are pre-ordained to it , which pre ordination , nature , gods vicegerent in the rule of the universe , doth fore-know by the suggestion of the divine spirit , that she might be ministerial to the compassing of it ; neither do those things casually fall out , but they have a necessary , though unknown cause , yet the grand ruler of all is not comprized within the law of necessity , but appoints all things , and changeth them according to his own will . he it is that decrees concerning all , even the least things , whose decrees want neither certainty nor order . therefore that order , that runs through the series and succession of things & times , hath the law of its necessity from the divine decrees . as all things which afterwards were actually produced and separated , in respect of their matter were potentially in the chaos , so all individuals before they come to light , are in the world in their matter and potentiality , and will in their time and order come forth and break into act , but when they fail and die , they return as rivers into the sea , into that general mass from whence they came , every nature recovering its proper region , and being to be brought again and again into natures shop ▪ are wrought into new beings upon her anvile . it may be this was that opinion of the pythagoreans , therefore exploded , because not comprehended concerning their tenet of transanimation . when the mixt body is dissolved , and the corruption of the frail elements come to a loss , the aetherial nature returns to its native home , and there is nothing left in the carkass but a perturbation and confusion of the elements , having lost their governour , then there reigns nothing but corruption , death , and darkness in the widowed matter , untill she through corruption be made fit for generation , and the virtue of heaven do again flow down into the matter thus disposed , and gathering and mingling the wandering elements , do re-kindle the weak light of a new form , which at length breaks forth , the forces of the elements being corroborated , and so compleats the new mixture . in that corruption which tends to generation , which is a corruption in the mean , and is done with the conservation of the specifical form potentially inherent in the seed or matter , that sublime spirit departs not , but being weak and impotent , is excited by external heat , and begins to move , and withal give motion to the matter , till at length it works more vigorously , and gives information to the perfectly mixed body . the elements as well as the aliments of nature , do begin their generation and nutrition , which are in most respects the same from corruption . for both must necessarily be putrified , and by putrefaction be resolved into a moist , and as it were a first matter , then is there made a chaos , in which are all things necessary for generation and nutrition . so doth the birth and repair of every microcosm bear with an analogical resemblance with the creation and conservation of the macrocosm . the insensible seeds of things , and those mixed bodies which are begot from them , do consist of a threefold nature , of a celestial , elementary , and mixt nature . the celestial is a ray of the light of the sun , endued with all heavenly vigour , the principle of action , motion , generation and life , by whose help the seeds , by their renewed vigour , do resemble the constant permanency of the stars , and being in a manner as so many immortal grafts of celestial plants , ingrafted upon corruptible nature , as upon a strange stock , do by a kind of an eternal succession , vindicate it from death : the elementary , corporeal and sensible portion , which in creatures is called the sperm , is the case and keeper of the seed , which putrifies and is corrupted , and generates an invisible seed . the radical moisture , or the ferment of nature , in which lyes the spirit , is a middle substance , coupling the celestial and elementary , in the material part answering the elements ; in the spiritual , the form . like the day-break , whose cheek being covered with a duskie light , doth knit together the two extreams of light and darkness , and being neither , doth hold forth a mixture of both . life is an harmonical act , proceeding from the copulation of the matter and the form , constituting the perfect being of an individual nature . death is the term or end of this act , the separation of the matter and form , and a resolution of the mixt body . these mixt bodies have the roots of their generation and life in heaven , from whence springs their causes and principles , whence also as inverted trees , they do suck their juice and aliment . neither is it suitable for the understanding , to be envassaled to the rule of the senses , which comprehend nothing but what is sensible . but the mind rangeth far abroad beyond the cloysters of the senses , and searcheth to a greater height , for the hunting out of the bounds of nature . the bodies are as it were the barks , the grosser parts of the elements the accidents of things , under which lye hid the pure and sprightly essences , which acknowledge not the subjection and censure of the senses , and which it was a necessity to cloth under a dark cloud , that they might pass from their heavenly , to their earthly province of the corporeal beings . the supream creatour of nature enacted this copulation of spirituals with corporeals , whereby his uncreated spirit communicating it self , first to the more spiritual and simple natures , might be conveyed through them , as by so many conduits , to corporeal beings , and in this manner diffusing it self gradually and orderly , through all the regions of the world , through all and every being , doth sustain all things by the divine presence , as also that by a sensible creature , the insensible creatour might be apprehended through corporeal and sensible resemblances . whatsoever lives either an animal or vegetable life , stands in need of food , that the natural spirits might be recruited , which do continually slide forth through the pores , and that so the loss of nature might have a successive repair . for the nourishing juice is made by the more succulent substance of the meat , whereby the parts and humours of the body are re-inforced . the radical moisture is renewed out of the purer portion of the humours , especially of the bloud , the celestial influence intermingling it self by respiration with it . living things have a two-fold nourishment , to wit , a corporeal and a spiritual , the former being of small avail to life without the latter . for vegetables do evidently referre the benefit of their increase and nourishment no less to the air and heaven , than to the earth : yea the earth it self , unless suckled with the milk of heaven , would quickly find her own breast to flag drie , this that holy diver into natures secrets , when he blessed joseph , doth thus express : blest be the lord for his earth , for the apples of heaven , for the dew , and for the deep that coucheth beneath , for the pleasant apples of the sun and of the moon , for the top of the everlasting mountains , for the fruits of the eternal hills , &c. by which mystical speech , the prophet fore-ensureth the earths plenty , by the abundant influence of the sun , moon , and of the rest of the celestial bodies . that spiritual diet , as far as it conduceth to the life of creatures , is acknowledged by every vulgar capacity , that sees the renewed respiration , and the frequent sucking in of the external air . for not onely according to the opinion of ordinary physicians , hath nature so workmanlike framed those bellows , bordering upon the heart to cool it , but also that by their continued fanning , they might breath in an aethereal air , and hand to it celestial spirits , that so by their recruits the vital spirits may be kept in repair , and be alwayes multiplied . philosophers do not onely call those spiritual natures , which being created without matter , are onely comprehended by the understanding , as the intelligencies , angels ▪ and devils are accounted to be : but also those that , which although they have their original from matter , yet in respect of their great tenuity & nobility , do not subject themselvs to the search of the senses , and nearer approching to spiritual beings , are rather under stood by reason , than found by sense such is the pure part of the air , such are the influencies of heavenly bodies , such the in-set fire and seminal virtues , such the vegetable spirits , such the animal , and the vital , and the like , in which consists the very nature of beings , than in grosser bodies . such like natures spring from heaven , and in relation to sensibles , do assume to themselves the name and right of spirits . it is suitable that we should give the fire of nature a place amongst the spiritual beings , for in it self it is not perceivable by any sense , but discovers it self onely in bodies , by heat and other effects and accidents . this is apparent in living creatures , into which by this unperceiveable fire , is infused a sensible heat , and that fire with the life stealing away , the elementary body or the carkass , yet the mixed being dissolved , remains sound and unhurt . in vegetables , because this fire is weaker , it doth elude the sense , and is not to be perceived by any heat . reason also convinceth , that our common fire is to be sorted amongst the spiritual , rather than corporeal beings . for if it were corporeal , it should have from it self a peculiar and inseparable body , no less than earth , water , or air , and the rest of the sensible natures , which do consist and are bounded within their proper bodies , which do exist in them and by them , which do act according to their virtues , and produce them to the senses . but fire hath not a peculiar and sensible body , lodgeth onely in anothers , for a coal is not fire , but wood fired , neither is the flame fire , but smoke inflamed ; finally , that robber onely feeds upon what is not his own , lives upon the prey , and is extinguished when this fails , having nothing in it self to feed it . besides , a body super-added to another body , doth augment the quantity of it , but this not found in fire put into wood or smoke , for the smoke or wood is no way increased by the accession of fire in their quantities , from which it is evident , that a fiery spirit rather than a body , doth invade the wood or smoke . a sword melted , the scabbard being untouch't , the bones shattered by the fiery bolt of thunder , and yet the flesh unhurt , do sufficiently argue the spiritual nature , even of that thundering fire . yet we must know that fire is not wholly immaterial , for it hath a matter , though a very subtile and light one , whereby it cleaves to the encompassing air , whereby it may be kept in by a more gross body . yet doth it rather deserve the name of a spirit , than of a body , because it hath not a sensible quantity , neither can it be comprehended , but when it is arrayed in another body . for light the original of it doth evince , that it ought to be seated amongst those things that are truly spiritual . there was no light but in god before the informing of the first matter , & the birth of the world . but when nature received her being , then began there a spiritual light to issue forth from the fiery spirit of god upon the matter , and there to settle as in its lamp , and this was the creation and original of light : that was the first act of the deity upon the matter ; the first copulation of the creatour with the creature , of a spirit with a body . therefore the first informing light , was a meer spirit , which did kindle with its fiery virtue , as with heat , the nearest matter , being exceedingly rarefied by its spiritual light , and so were the darkness converted to light . the heaven , being distinguished by the first light , although it be not material and fiery , yet is nevertheless invisible , because in respect of the matter , it is brought to the highest degree of tenuity , and in respect of its form , is endowed with spirituality . but the light that was scattered in the middle heaven , being bounded into a narrower compass , was cast into the globe of the sun , which was necessarily to be formed into a kind of a thick body , as it were into a smoke fit to be kindled , yet not combustible , that so it might be setled , being kindled by that immortal light , and be in the room of the general lamp of nature , or as a fiery mass . the light of the sun therefore is nothing else but a lightsome spirit , deriving its rise from the spirit of eternal light , gathered in , and inseparably cleaving to the body of the sun , and made sensible by reason of the thickness of the body , communicating to all the natures of the universe , light , and a manifold virtue : constituting the spirit of the world by its non-intermitted influence : and bound up in a body for the good and welfare of the corporeal nature . yet the sun-beams that are perceivable by our eyes , are not pure spirits , for issuing continually from the sun , have their progress , being clothed with the encompassing air . they are therefore nothing else but a continued flowing forth of the spirit of light , which springing forth as so many rivulets from their eternal fountain , and working themselves into the aetherial nature , as a flame into a most thin smoke , do over-spread the whole face of the universal world with their light . it is natural to light to flow continually from its fountain . we call those rays issuing forth , and mixing themselves with the airy nature , and they are the first actings of light in the sun , and the conveyance of it from the sun . for it is the property of a lightfull body , to act by it rays , and to send forth heat and light , and that might spread its light abroad by a darting forth , and multiplying of its beams . we do by light signifie both the first act of the lightsom body , as also a secondary lightsomness which floweth out from the former . the lamp being out , either for want of matter , or blown out by the wind , the fiery and lightsom spirit that kindled the lamp doth not perish , neither is it extinguished , as it commonly seems , but onely loosing what it feeds on , and being stript from it , is scattered in and vanisheth to air , which is the abyss and universal receptacle of all lights and spiritual natures of the material world : from whence we may learn , that the nature of this lightsomness is spiritual , and is derived from the spiritual fountain , not otherwise than natural forms from their matrix , which is the spirit of the universe , perpetually flowing from the sun , as from an eternal and immortal spring . for as the bodies of mixt beings in their making , do rise from the first matter , and the elements , and do gradually at their departure , slide into the same again , so the natural forms of individuals in their approch , do flow from the universal form ( which in the manner of a form of forms , doth inspire a formal virtue into the seeds ) and in their recess do again return into it . but that form is the spirit of the light of the universe , to which , as to their principle , and as to a nature of the same kind , do all single forms and sparks of light got loose from their tyes , return . so are all mixt beings resolved into their first principles , but these principles do return to that eternal spring of nature , as to their proper centre and peculiar countrey . but that spirit of the universe is from the sun , yet not the very light of the sun , conspicuous to us by reason of the presence of its body ; but that invisible spirit , which is continually dispersed by the beams of the sun , through the universal region of the air , and doth extend it self perpetually by communication through our heaven , yea , even to the centre of the earth , and that in the absence of the sun , and in the darkest night , pouring out all gifts for generation and life , through all the bodies of the universe . the divine love was not able to contain it self within it self , but did wholly go out of it self in the creation , by multiplication of it self , and pouring out himself wholly also in the conservation of creatures in themselves . light also , which is the exactest copie of the deity , doth also imitate the divine love : for it is not able to be comprized within its own lightsom body , but is diffused far and near for the good of other beings , by a strong multiplication of its beams , being not so much born for it self as for others , being as it were the token of divine love , communicating it self to its power , and reaching forth into the most remote places , unless it meet with a stop from a thick bodie . light also doth hold forth to us the infinite nature of god ; for the small light of a lamp or candle cannot , as long as it is fed , by all its continued effluence of rays , and by its infinite communication of its flames , be exhausted or diminished . as many beams so many streams flow from it . yet though it gives , though it diffuseth it self , although much be taken from it , yet is it not brought to nothing , neither receives loss , which is the alone property of a spiritual nature , and is altogether unappliable to a corporeal . so the intellectual endowments , as the understanding and knowledge of things , which are justly esteemed spiritual lights , are of the same kind , that though alwayes bestowed abroad , yet are preserved entire at home . therefore must we confess that there is something divine in light . the beams of a lightsom body , although they be of a spiritual nature , yet are they stopt by a thick body , because their conveyance is by means of the air , without which they are not perceivable by us , by which copulation also they are in a manner made corporeal , and therefore cannot pierce or enter into the bodies that are not porous . so spiritual things do act with us by some sensible mean , that so we may perceive them to act . but the lightsom body being absent , the beams also depart , neither do they part from his presence , because they immediately flow from him . but the air is without enlightened , not onely by the presence of a body of light , and of the beams from it , but also the body being gone , and the beams withdrawn , by a lightsom spirit flowing from them : as is clear in the darkest eclipse , or the heavens over-cast with the blackest clouds , or wrapt up in the mask of night , yea , the sun being sunk under the horizon : for that act of present light cannot proceed from the body of light , and its beams being absent , but from the access and presence of a spiritual light . a transparent body as glass , being pointed with the sun beams , doth gather them , and receives in it the image of the sun , and is made lightsom , & as it were a brief draught of the sun , which sends forth its beams on the farthest side opposite to the sun , from which the beams of the sun being refracted , by the concourse of the glass , seem to pass through the glass , which yet indeed they do not , for the rays by reason of the air that cleaves to them , are setled about the glass , the spirit of light onely passing forward , but by the beams which are darted out on the other side , are the beams of the sun , or of the glass being kindled by the sun-beams into a lightsom bodie . every transparent body , especially glass , is a medium of light , because it receives light into it , and having received it , doth communicate it to the air that is beyond it , not by the sending forth of lightsom air about it , which is repugnant to nature , but by another double way . first , because a transparent body yields to , and le ts pass the spirit of light , and doth send it forth abroad being received by it , which sent forth , gets into the adjoyning air , hence springs that plentifull light ; and besides , because that transparent medium is made by the benefit of the light , it receives not onely light in it self , but lightsom to others , and by the spirit of light , which is in love with transparent bodies , becomes as it were a lighted lamp . but now every lightsom body hath the priviledge and power to scatter its light , which is not granted to thick and dark bodies , unless by reflection . those which are the pure natures of mixt beings , are mearly spiritual , the bodies are as it were the barks and vessels , in which they are contained and kept . and not otherwise could those sublime natures , unless tied to the corporeal elements , and so bound in by their weight , pass this lower sea , and lodge in the centre of this abyss . they come subject to sense by their bodies , the bodies are moved and acted by them , so do they do interchangeable offices . this that secret of homers juno , whom jupiter let down with a weight at her heels . since the whole frame of the universe is but one onely body , one onely universal nature , consisting of many natures and bodies , bound together by their proper mediums and bonds , it should not be wondered at , that such parts & members are knit together by a strong , but secret tye , and do give a mutual assistance each to other , for they have not onely a mutual relation to , but also a communication with one the other , and these various natures do exercise a kind of a commerce , the extreams by the middle , the middle by the nearest . but this communication is performed by spirits sent forth : for all the parts of the world , all the individual natures of the world do abound in spirits ; many of which flowing forth , leave room and give way for those that flow in , and so is there by the continual ebbing out and flowing in of spirits , a continual reparation of the world , and of the natures thereof . this is the scale of general nature presented in a vision to the patriarch jacob , these are mercuries wings , by whose help being mistically termed by the ancients , the messenger of the gods , he was thought frequently to visit the coasts of the earth , and the courts of heaven . the active principles of every kind of vegetables or animals are spiritual , their bodies are the passive organs of the spirits , by which they exercise the faculties of the senses , and do by various actings put forth their powers , as the authours of actions , so that in the general life may be termed a concent of actions , or a continued act diversified by the multiplicitie of actions , flowing from a spiritual fountain , and brought forth by corporeal organs . it is the propertie of the spiritual nature to act , of the corporeal to be passive , where therefore there is a concourse of both , as in mixed bodies , that as the more noble doth act and rule this as passive doth obey . for the power of act is the priviledge of ruling , but the burden of being passive is the mark of being servile ; so the in-set fire in the seed , is the principle of generation and life , the highest operating spirit , the archaeus of nature , the orderer in the preparing and forming the matter in the mixtion and distribution of the elements . so doth the form in the mixt being exercise its rule at his will , as the fountain of all actions . so do the virtues of the heavenly beings dispose and seal all inferiour elements and corporeal matter . natural bodies which have an active vigour , and an occult cause of acting , do not , as is commonly thought , act alone by their qualities , but by secret spirits . for the fire doth not heat and burn by the single qualitie of heat , but by the continual flux of spirits and rayes . neither do the earth and water refrigerate or moisten by the alone qualities of cold and moist , but by their vapours and in-nate spirits sent forth , do affect the sense from without . neither do poysons onely by cold or hot qualities , but by malignant spirits bring death or infection sooner or later . concerning plants or herbs , we must judge alike , because their active virtues do not lie hid in their qualities , but in their essence , which nature hath made abundant in spirits , whose basis and principle powers are concerning spirituals , for the bodies are as the shadows or the investments of things , under which the invisible nature is hidden , but since qualities are the accidents of things , are not therefore able to constitute their essence , nor shew forth in their actings those wonderful virtues , but are onely as the in set instruments of actions & passions , which the working spirits , that are the workers of all actions make use of in their actings , but yet nature indures them not as principles and efficient causes of actions . the natural tinctures , odours and tasts of things are special and spiritual gifts of nature , with which it hath suitably inriched her beings , & which do not onely contribute to their ornament , or onely are inherent in them , as extrinsecal accidents , but also have an in-set and radical cause , and are not so much to be termed accidents , as demonstrative tokens of inward virtues , by which the occult and formal signatures of things discover themselves . rarefaction and condensation are the two instruments of nature , by which spirits are converted into bodies , and bodies into spirits , or also by which corporeal elements are changed into spiritual beings , and spiritual into corporeal ; for elements do suffer these changes in mixt bodies . so the earth doth minister spiritual food to the roots of vegetables , which being fed upon , doth go into the stalk , the bark , the boughs , the branches , the flowrs , and into the corporeal substance . the same is done by nature in animals . for the meat and drink , which they diet on , or at least the better part , is terminated into humours , and at length into spirits , which getting through the pores , and knit to the flesh , nerves , bones , and the rest of the parts of the bodie , do nourish and augment them , and do by the never-tired work of supply , repair decaying nature . so the spiritual and the portion of the purer substance , is curdled to the frothie bodie of seed . art the ape of nature , doth experience the like in her resolutions and compositions . the life of individuals is in a rational and strict union of the matter and form : but the knot of both natures , their tie and base lieth hid in the fortified embraces of the innate heat and fire , and the radical moisture . for that formal fire is an heavenly ray , which is united with the radical moisture , which is the purest and best digested portion of the matter , and as it were an oyl defaecated , exuberated , and turned as it were into a spiritual nature , by the organs of nature , as by so many alembicks . there is much of the radical moisture in the seed of things , in which , as in its food , is kept a celestial spark , which doth act all things necessarie to generation in a convenient matrix . but wheresoever there is a constant principle of heat , there is conceived to be a fire , because the natural principle of heat is his in which it is , a man may observe something immortal in the radical moisture , which doth neither vanish by death , nor consume by the force of the most violent fire , but remains unvanquished in the carkases and ashes of bodies burnt . there is a double moisture lies in every mixed being , to wit , an elementarie and a radical . the elementarie , being partly of an aeriall , parly of a watrie nature , yields not to fire , but flies away into a vapour or smoke , which being drawn forth , the bodie is resolved into ashes ; for by it , as by a glue , the elements in their mixture are knit together . but the radical moisture scorns the tyrannical assaults of common fire , but it neither dies in the martyrdom , nor flies away in the combat , but surviving the mixt bodie , doth stubbornly stick to its ashes , which is an evidence of its exact puritie . the experience of this radical moisture , hidden in the ashes , did teach a secret to the glas-makers , being ignorant of the nature of things , for by bringing glass out of ashes by the sharp point of their casting flames , they have made a hidden thing evident , beyond which , neither the strength of fire or art are able to stretch it . but the ashes must necessarily run , that there might be a continued quantitie , and a solid bodie made as glass is , which could not be otherwise , for there can be no flowing of any thing without moisture . therefore that moisture being inseparable from its matter , is at length brought to terminate into that noble and as it were aetherial transparent bodie . the extraction of salts out of ashes , in which is the chief virtue of mixt beings , the fertilitie of ground increased by the burning of stubble , and by ashes , doth evidence , that that moisture preserved free from fire , is the radical principal of generation , & the root of nature . although this virtue lies hid , solitarie and idle , till being received by the earth , the common matrix of natures principles , yet shew forth a hidden facultie convenient for generation and multiplication , as it is also accustomable in the seed of things . that radical balsame , is natures ferment or leaven , infecting the whole mass of the bodie . it is an indelible and multiplying tincture , for it pierceth and tingeth even the more loathsom excrements , which is evident by the frequent , although imperfect generation , that is made from out of them , as also by the frequent dunging of ground , which is known by the most unskilfull husbandmen , that so the languishing land may be set forward to pay its due , and that with an advantage to the expecting labourer . we may guess , that that root of nature , which survives the ruin of the mixt bodie , is a foot-step , and the purest and immortal portion of the first matter informed , and signed with the divine character of light . for that ancient matrimonie betwixt the first matter and its form , is not to be untied , from which copulation the other bodies drew their original . moreover , it was necessarie that this incorruptible base of corruptible things , and as it were the cube-root of them should lie hid , always remaining and immortal in the depth of bodies , that it might be constantly and perpetually a material principle , having a potentiality and aptitude to life , about which , as about an immoveable axle-tree , there might be a continual turning of the elements and things . and if we may have the liberty in dark things , to guess at what is most likely truth , that immortal substance is the foundation of the material world , and the ferment of its immortality , which the eternal measurer of all things hath fore-established to survive the day of the conflagration of all things , when the elements shall be purified by that refining fire , that so he might renew and repair out of this pure and ever-remaining matter , his work vindicated from original sin , and the taint of corruption . that this radical basis is not of the kind of special forms , is evident , because every individual hath its individual and singular form , which doth depart the body upon the dissolution of the mixt being , yet that radical principle remaining unextinguished , although it abide much weakened , and of little efficacy , by reason of the absence of the form , yet do those vital sparkles remain apt for the production of more debased and imperfect births , which production belongs not so much to nature , as to the matter in its birth ; this attempteth , but is not able to generate without a companion , by reason of the absence of the formal and specifical virtue . so the carkass of a man or an horse , by reason of the defect of seed is not capable for the generation of a man or an horse , but of loathed worms and other insects , from whence we may guess , that that feeble principle of life proceeds from the scarcity of the first matter , and rather to be of the family of the lower elements , than of the higher and celestial , yet that there is in it some of that tincture of light . for certainly that slight spark of that former light , which did in the beginning inform the dark matter of the lower abyss , may be sufficient for the generation of insects : for it doth work the matter by a confused and disordered motion , that it might bring forth the power into a feeble act , but the matter warmed by this spark , and as it were languishing , being corrupted rather by the fancy than the copulation of a male , doth rush into the lustfull act , and being unable to bring forth a just issue of nature , doth form loathsom phantasms , as worms , hornets , beetles , and the like , in the filthy excrements . therefore that radical moisture is the nearest and never-ceasing subject of generation and life , in which is first kindled the fire of nature , and the formal act in a well disposed and prepared matter . but in a confused and ill ordered matter , where that humour doth act the part of the male , it begets spurious and bastard births of nature , for that generation which is made without specifical seed , seems to be made rather by chance and default , than by the intention of nature , although in it seems to be a dark and confused kind of copulation of actives with passives , which is required also to the production of every , though imperfect , being . that radical ferment constantly abiding in the depth of mixt bodies , seem to be the band , seat and tye of that matrimony contracted between light and darkness , between the first matter and the universal form , finally of all the contraries : otherwise the matter and form , by reason of their repugnant natures , would not be knit together . but that dark unbridledness of the first matter and its averseness from light was tamed , and its hatred turned into love , by the good office of that lightsom tincture , which doth reconcile things repugnant . the inbred heat and the radical moisture are of a divers kind , for that is wholly spiritual and of the sun , this of a middle nature , betwixt a spiritual and a corporeal , both participating of an aethereal and elementary nature ; that is of the degree of things above , this of things below , in which was celebrated the first marriage of heaven & earth , by which also heaven hath its abode in the very centre of the earth . they are therefore deceived , that do confound the inbred heat and the radical moisture , for they differ no less than smoke and flame , the light of the sun and the air , sulphur and mercury : in mixt beings , the radical moisture is the seat and food of the inbred and celestial fire , its bond with the elementary body : but that power of fire is the form and soul of mixt beings . in seeds , that moisture is the immediate keeper and case of that spirit of fire inclosed in the seed , till it be set on to generation in a disposed matrix , by an adventitious heat . finally , that radical substance is vulcan's shop in every mixt being , the chimney in which is kept that immortal fire , which is the first mover of all the faculties in an individual nature . that radical moisture is the catholical balsam , the most precious elixar of nature , the mercury of life , having a perfect sublimation by nature , a dose of which is administered to every individual of her family , weighed to a just quantity by plenteous nature . they that have attained the happiness to fetch out this hidden treasure of nature , wrapt up close in the heart , and in the closets of natures birth , and can get it out of those close coverts of the elements , let him boast that he hath attained the chiefest staff and help of life , and a most precious treasure , the order of reason and of creation doth require , that the first copies of things , being first of all concealed in the celestial natures , were transmitted into inferiour beings : but in the first they are of a far greater perfection , both because of their greater tenuity and dignity , as also because of their neighbouring seats to the eternal being : but with us they are much meaner , because carved in a grosser and less valuable matter , and more distant from their eternal principle . there is nothing therefore printed in this lower margin of the world , which was not at first copied in the heavenly being : neither is there any particular kind of being of the inferiour natures , which doth not acknowledge the dominion of one superiour agreeable to it , and which it hath not the secret seal and signature of it . so do things below depend on things above . the world is a creature of an ambiguous nature , for it is of both sexes , the higher part , to wit , the celestial , is active and masculine ; the lower elementary nature , is the passive and feminine nature . the globe of the earth is the womb , in which the engendering seed of heaven is received and kept . from the masculine part proceed life and strength ; from the female part corruption and death do issue . since superiour and inferiour bodies have their original from the same principles , as from their parts , yet are they not such as have their equal lot : it is equal , that those things that have the honour of being nobler substances , and advanced to higher offices , should distribute to their brethren of a lower degree , being poor and in want , some of their wealth , and so provide for their life and conversation . for it was provided by the foresight of the deity , that since there was a necessity that the world should be made up of unequal natures , the more powerfull natures should aid the weaker , & hand help to the fainting natures . so love is the indissoluble knot of the parts of the universe . in this sublunary region , diseased nature sickens out of a defect of the proportion and temperament of the elements , either by reason of the quantity , or of the qualities , either out of a too great intension or remission , and so is there a dissonancy in natures musick , and a distemper in her bodies . therefore the consonancy of the elements , which riseth from a proportion , and constitutes their temperament , being gone , the matter and form of the whole mixt being hath a bad coherence ; nature is troubled and staggers with a perplexed confusion , and hence do first diseases , and then death assault disordering and falling nature . that discord of those principles , have either an intrinsecal and radical cause , as from a vicious seed , an evil generation , or age ; or an intrinsecal and accidental , as from a too great repletion or emptiness , from whence either an excess or defect in humours and spirits ; or from putrefaction , mortal poison , infection , grief , hurt , or some other impediment brought upon the organs of life with the like , which do hurt nature . the four radical qualities of the elements , are as so many harmonious tones of nature , not contrary but divers , and distant each from other by certain pauses , from whose rational difference , intension and remission , is made a perfect consent of nature , perceivable by the understanding , bearing an analogy to that vocal musick which is heard by the senses . sharp and flat in musick , though they are extreams , yet are not contraries in musick , they are the terms of those means , which lye betwixt them , and are composed and tempered after a divers manner by these two extreams . so heat and cold , driness and moisture , are the extream qualities in nature , yet not therefore contrary , but onely the bounds of the middle and interjacent qualities , from whose mixture and temperament , do the middle proceed . the motion of nature is continual and not tyred , no less in every part than in the whole . for she always acts , never idle , so that if she were but out of action for a moment , it would ruine the whole frame of the universe , which is addicted to a decree of a perpetual motion . for neither doth the setled earth , the calm sea , the quiet air , therefore altogether rest , because they are not seen to be moved , they rest no more than a sleeping man : that rest is a remission of action , not an omission or cessation . nature acts within , neither doth it ever desist its action or motion of the organs . even a very carkass hath a motion , to wit , of corruption : but living beings , though they are not acted by a local , yet are they by an organical motion . nature doth move the frame of the universe in a uniform and orderly motiō , yet so that wheels things unequal and unlike , by an unequal unlike motion . this unequality of the motion is required by a geometrical equity , and so all the motions of all the heavenly bodies , may be geometrically termed equal , considering the difference of the magnitude , distance , and nature of them . nature being no less powerfull than wise , in the informing and governing of her works , doth attain her certain end by many wanderings and windings , which is most evident in the births of the earth , for she handling the elements in an unequal temper , doth , especially in the winter , replenish the womb of the earth with a fruitfull seed , in the spring brings forth an easie birth , in the summer ripens the fruit , and in the autumn all fall . this diversity doth especially proceed from the approch and recess of the sun , appointed to this end by the creatour : for he hath destinated the sun to the rule of the elements , that by his various distance , inflection and reflection , they may have a divers and various temperament , and so there might be some help for nature , working divers things by divers means , and that she might perfect her changes , by the various changes of times . this variety of nature is worth the exactest thoughts of the most acute philosophers . the heavenly bodies , though not subject to that stain of alteration , do notwithstanding introduce manifold changes in the elementary region , and do inspire various affections by their divers propension , and the various motions of the planetick bodies , which do alter their site and distance between themselves , and also the figure of the heavens , which actions do diversly form and incline the pliable natures of the elements , and they never cease to ferment them by their continual influence . the whole substance of the heaven , hath parts continuous , though not contiguous ; let not any therefore fancie the world to be the works of art , which is the work of nature , which cannot endure any section into sphears and circles ; for they that first divided the aetherial region into many orbs and circles , did propose to themselves rather the easie teaching by it , than to shew the truth of the thing . for the divine nature being an unitie , is desirous of and endeavours unitie , and so avoideth multiplicitie : wherefore we must conceive she created not many heavens , separated by their matter and superficies , when one bodie , in respect of the continuitie of the matter , though distinct in the dignitie and virtue of the parts , might suffice . neither is this taken off by the motions of the stars in their courses and customs , which because we know not , we therefore make a fancied astrologie , and do too boldly bring the power of god under the weakness of man , though the continuitie of the heaven hinder not the motion of the stars , and there might be some help for mans reason to find out their orders , that there should be a first moveable above the heavens , by whose hurrying motion the lower heavens are turned about , is not an invention of the wisdom of god , but onely a fancied help for mans ignorance : for if we assign the principle of motion to that first mover , why do we denie it to the globe of heaven ? why should we fancie an external cause of motion , which may be all this time intrinsecal ? as this lowest province of the world is subject to the rule of the middle , so is the middle , viz. the aetherial to the highest and supercelestial for its priviledges and deputieship . for the empyrean heaven , and the quire of the intelligible beings , do inspire into the celestial orb those virtues , which they receive from the archetype , in order of succession , and do move those natures that lie nearest them , not without a concent , as the first organs of the material world : by which motion the inferiour bodies , being also moved , do exercise their turns , as so many dances to a set pace , and do borrow whatsoever is excellent from the superiour bodies . but intelligences are illuminated at hand , according to their orders from the mind of god , as from the spring of eternal light , by which illumination they are fed , as with an immortal food , and in it , as in a glass , do they read , receive the commands and will of the divine majestie , and by it are enkindled to an honourable obedience . this is the manner and union of the threefold nature of the universe , the knot and herculean bond of this union is the love of god . so in a ternarie is compleated the whole state of the world , whose creatour is by no means part of it , no otherwise than unitie is neither a number , nor the part of a number , although it constitutes all number , but is the principle and measure of number , neither is the musician or lutonist a part , but the authour of the concent . they which believe that an almost innumerable multitude of heavenly bodies , were created for the commoditie of the globe of the earth , and for her inhabitants , as to their proper end , are deceived , for reason will denie , that natures , so far more noble and transcendent , were enslaved to the service of more vile and low-born beings . is it not rather more likely , that every globe doth rather of it self make a peculiar world , and that so many worlds as feodaries to the eternal empire of a god , are diffused through the vast range of the heaven , and there do hang as bound each to the other by that common bond of the heaven , and that the whole large universe doth consist of those manifold natures ? these , though so far severed in nature and place , yet do joyn in a mutual love , so as to make up a perfect harmonie in the universe , the heaven is the common place of all , yet is it more pure about those more perfect beings , therefore it is of great tenuitie and almost spiritual , and so fils up the places between , that so it may the better receive the various affections of so many natures , and the secret virtues continually issuing from them , and having received them , it might swiftly communicate them to others , though far distant . for the heaven is natures conveyance , by the mediation of which , all the cities of nature do traffique one with another , and are made partakers of each the others wealth and store . so are they linked together by a most powerfull bond of friendship and nearness , as it were by some magnetick virtue . what hinders , but that we may reckon the globe of the earth , as well as the moon amongst the stars ? for both are naturally dark bodies , both do borrow light from the sun , both are solid bodies , and reflect the beams of the sun , both send forth spirits and virtues , both hang in their heaven or their air . but the doubt is , whether it moves or no . but to what end is her motion needfull ? why may not she also stand fixt amongst so many fixt bodies ? and it may be the moon hath her inhabitants , for it is not credible , that orbs of so immense and vast a compass , should be idle and useless , not inhabited by any creatures ; that their motions , actions , and travels should onely tend to the good of this lowest and most despicable globe : since god himself , not liking solitude , did go out of himself in the creation , and poured out himself upon the creatures , and gave them a law for multiplication . is it not more for gods glorie , to assert the intire fabrick of the whole universe to be like a great empire , graced with the various natures of many worlds , as with so many provinces or cities ? and that the worlds themselves are as so many habitations & tenements for innumerable citizens of divers kinds , and all created to set forth the superlative glorie of the great creatour . and who will not admire the sun as an immortal lamp , hanging up in the middle of the hall of the great lord , and enlightening all the corners & recesses of it , or else as the vicegerent of the divine majestie , infusing light , spirit and life into all the creatures of the world ? for it was fit that god , being altogether immaterial , should rule and order his material works by an organ , which should be of a middle and most excellent material being , which also ought to be full of vivifical spirits , and so to set over sensible things , a sensible monarch . this doctrine of many worlds is not repugnant to scripture , which doth onely relate to us the creation of our world , describing all things concerning the others in a mystical , rather than an open & clear way , onely touching at them , that so mens feeble souls , that had alreadie fallen , as too curious of knowledge , might rather sit and admire , than rise and understand . the clouding of this truth , this darkness of mans soul , was part of the punishment of sin , by which he fell from the pleasures of paradise , the delights of knowledge , the knowledge of nature and heavenly things , that so he that would stretch himself to a sinfull desire of a forbidden knowledge , might be nipt by a just deprivement of what was given : and so he having brought in a multiplication and confusion of knowledge , might be punished with the loss of that true knowledge , which was one of all things . that is the cherub , the guardian of the garden , he that hath his flaming faulcheon , striking blind the guiltie souls of men with the brightness of his light , and forcing us off from the secrets of nature , and the truth of the universe . the divine nature , although it be a most perfect unitie , yet seems to consist of , and to be perfected by two things , viz. understanding and will . by his understanding , he knows all things from eternitie ; by his will , he acts all ; and both he doth most absolutely . his knowledge and wisdom belong to his understanding : but his goodness , mercy , justice and the rest of those virtues , which are accounted moral with us , belong to his will ; yea so doth also gods omnipotencie , which is nothing else but his omnipotent will . the intelligible natures , viz. the angelical nature , and the soul of man , which are small draughts of the divine nature , have also these two faculties , according to their weight and measure . for in them the understanding is the organ of knowledge , the will of working , and beyond these can they not act . finis . notes, typically marginal, from the original text notes for div a e- in pimand . in smarag . tab lucret. nu . . * cap. . l. . de ort . & interitu . † cap. & . de ort . & interitu de sariis philo's sopinion . the creation of the sun lucret. lib. . cap. . l. . de mat. aeneid . . psal. . lib. . de diaeia . deut. cap. . decameron physiologicum, or, ten dialogues of natural philosophy by thomas hobbes ... ; to which is added the proportion of a straight line to half the arc of a quadrant, by the same author. hobbes, thomas, - . approx. kb of xml-encoded text transcribed from -bit group-iv tiff page images. text creation partnership, ann arbor, 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(eebo-tcp ; phase , no. a ) transcribed from: (early english books online ; image set ) images scanned from microfilm: (early english books, - ; : ) decameron physiologicum, or, ten dialogues of natural philosophy by thomas hobbes ... ; to which is added the proportion of a straight line to half the arc of a quadrant, by the same author. hobbes, thomas, - . hobbes, thomas, - . proportion of a straight line to half the arc of a quadrant. [ ], p. printed by j.c. for w. crook ..., london : . reproduction of original in union theological seminary library, new york. created by converting tcp files to tei p using tcp tei.xsl, tei @ oxford. re-processed by university of nebraska-lincoln and northwestern, with changes to facilitate morpho-syntactic tagging. gap elements of known extent have been transformed into placeholder characters or elements to simplify the filling in of gaps by user contributors. eebo-tcp is a partnership between the universities of michigan and oxford and the publisher proquest to create accurately transcribed and encoded texts based on the image sets published by proquest via their early english books online (eebo) database (http://eebo.chadwyck.com). the general aim of eebo-tcp is to encode one copy (usually the first edition) of every monographic english-language title published between and available in eebo. eebo-tcp aimed to produce large quantities of textual data within the usual project restraints of time and funding, and therefore chose to create diplomatic transcriptions (as opposed to critical editions) with light-touch, mainly structural encoding based on the text encoding initiative (http://www.tei-c.org). the eebo-tcp project was divided into two phases. the , texts created during phase of the project have been released into the public domain as of january . anyone can now take and use these texts for their own purposes, but we respectfully request that due credit and attribution is given to their original source. users should be aware of the process of creating the tcp texts, and therefore of any assumptions that can be made about the data. text selection was based on the new cambridge bibliography of english literature (ncbel). if an author (or for an anonymous work, the title) appears in ncbel, then their works are eligible for inclusion. selection was intended to range over a wide variety of subject areas, to reflect the true nature of the print record of the period. in general, first editions of a works in english were prioritized, although there are a number of works in other languages, notably latin and welsh, included and sometimes a second or later edition of a work was chosen if there was a compelling reason to do so. image sets were sent to external keying companies for transcription and basic encoding. quality assurance was then carried out by editorial teams in oxford and michigan. % (or pages, whichever is the greater) of each text was proofread for accuracy and those which did not meet qa standards were returned to the keyers to be redone. after proofreading, the encoding was enhanced and/or corrected and characters marked as illegible were corrected where possible up to a limit of instances per text. any remaining illegibles were encoded as <gap>s. understanding these processes should make clear that, while the overall quality of tcp data is very good, some errors will remain and some readable characters will be marked as illegible. users should bear in mind that in all likelihood such instances will never have been looked at by a tcp editor. the texts were encoded and linked to page images in accordance with level of the tei in libraries guidelines. copies of the texts have been issued variously as sgml (tcp schema; ascii text with mnemonic sdata character entities); displayable xml (tcp schema; characters represented either as utf- unicode or text strings within braces); or lossless xml (tei p , characters represented either as utf- unicode or tei g elements). keying and markup guidelines are available at the text creation partnership web site . eng physics -- early works to . - tcp assigned for keying and markup - apex covantage keyed and coded from proquest page images - jonathan blaney sampled and proofread - jonathan blaney text and markup reviewed and edited - pfs batch review (qc) and xml conversion licensed may . . ro. l'strange . decameron physiologicum : or , ten dialogues of natural philosophy . by thomas hobbes of malmsbury . to which is added the proportion of a straight line to half the arc of a quadrant . by the same author . london : printed by j. c. for w. crook at the green dragon without temple-bar . . the contents . dial. . of the original of natural philosophy . pag. . . of the principles and method of natural philosophy . p. . . of vacuum . p. . . of the systeme of the world. p. . . of the motions of water and air. p. . . of the causes and , effects of heat and cold. p. . . of hard and soft , and of the atomes that fly in the air. p. . . of gravity and gravitation . p. . . of the loadstone , and its poles ; and whether they shew the longitude of places on the earth . p. . . of transparence , refraction , and of the power of the earth to produce living creatures . p. . the proportion of a straight line to half the arc of a quadrant ; by the same author . p. . cap. i. of the original of natural philosophy . a. i have heard exceeding highly commended a kinde of thing which i do not well understand , though it be much talkt of , by such as have not otherwise much to do , by the name of philosophy . and the same again by others as much despised and derided . so that i cannot tell whether it be good or ill , nor what to make of it , though i see many other men that thrive by it . b. i doubt not , but what so many do so highly praise must be very admirable , and what is derided and scorn'd by many , foolish and ridiculous . the honour and scorn falleth finally not upon philosophy , but upon the professors . philosophy is the knowledge of natural causes . and there is no knowledge but of truth . and to know the true causes of things , was never in contempt , but in admiration . scorn can never fasten upon truth . but the difference is all in the writers and teachers . whereof some have neither studied , nor care for it , otherwise than as a trade to maintain themselves or gain preferment ; and some for fashion , and to make themselves fit for ingenious company : and their study hath not been meditation , but acquiescence in the authority of those authors whom they have heard commended . and some ( but few ) there be , that have studied it for curiosity , and the delight which commonly men have in the acquisition of science , and in the mastery of difficult and subtil doctrines . of this last sort i count aristotle , and a few others of the ancients , and some few moderns : and to these it is that properly belong the praises which are given to philosophy . a. if i have a minde to study ( for example natural philosophy ) must i then needs read aristotle , or some of those that now are in request ? b. there 's no necessity of it . but if in your own meditation you light upon a difficulty , i think 't is no loss of time , to enquire what other men say of it , but to rely onely upon reason . for though there be some few effects of nature ( especially concerning the heavens ) whereof the philosophers of old time have assigned very rational causes , such as any man may acquiesce in , as of eclipses of the sun and moon by long observation , and by the calculation of their visible motions ; yet what is that to the numberless and quotidian phaenomena of nature ? who is there amongst them or their successors , that has satisfied you with the causes of gravity , heat , cold , light , sense , colour , noise , rain , snow , frost , winds , tides of the sea , and a thousand other things which a few mens lives are too short to go through , and which you and other curious spirits admire ( as quotidian as they are ) and fain would know the causes of them , but shall not finde them in the books of naturalists ; and when you ask what are the causes of any of them , of a philosopher now , he will put you off with mere words ; which words , examined to the bottom , signifie not a jot more than i cannot tell , or because it is : such as are intrinsecal quality , occult quality , sympathy , antipathy , antiperistasis , and the like . which pass well enough with those that care not much for such wisdom , though wise enough in their own ways ; but will not pass with you that ask not simply what 's the cause , but in what manner it comes about that such effects are produced . a. that 's cozening . what need had they of that ? when began they thus to play the charletants ? b. need had they none . but know you not that men from their very birth , and naturally , scramble for every thing they covet , and would have all the world , if they could , to fear and obey them ? if by fortune or industry one light upon a secret in nature , and thereby obtain the credit of an extraordinary knowing man , should he not make use of it to his own benefit ? there is scarce one of a thousand but would live upon the charges of the people as far as he dares . what poor geometrician is there , but takes pride to be thought a conjurer ? what mountebank would not make a living out of a false opinion that he were a great physician ? and when many of them are once engaged in the maintenance of an errour , they will joyn together for the saving of their authority to decry the truth . a. i pray , tell me , if you can , how and where the study of philosophy first began . b. if we may give credit to old histories , the first that studyed any of the natural sciences were the astronomers of aethiopia . my author is diodorus siculus , accounted a very faithful writer , who begins his history as high as is possible , and tells us that in aethiopia were the first astronomers ; and that for their predictions of eclipses , and other conjunctions and aspects of the planets , they obtained of their king not onely towns and fields to a third part of the whole land , but were also in such veneration with the people , that they were thought to have discourse with their gods , which were the stars ; and made their kings thereby to stand in awe of them , that they durst not either eat or drink but what and when they prescribed ; no nor live , if they said the gods commanded them to die . and thus they continued in subjection to their false prophets , till by one of their kings , called ergamenes , ( about the time of the ptolemies ) they were put to the sword. but long before the time of ergamenes , the race of these astrologers ( for they had no disciples but their own children ) was so numerous , that abundance of them ( whether sent for or no i cannot tell ) transplanted themselves into egypt , and there also had their cities and lands allowed them , and were in request not onely for astronomy and astrologie , but also for geometry . and egypt was then as it were an university to all the world , and thither went the curious greeks , as pythagoras , plato , thales , and others , to fetch philosophy into greece . but long before that time , abundance of them went into assyria , and had their towns and lands assigned them also there ; and were by the hebrews called chaldies . a. why so ? b. i cannot tell ; but i finde in martinius lexicon they were called chasdim , and chesdim , and ( as he saith ) from one chesed the son of nachor ; but i finde no such man as chesed amongst the issue of noah in the scripture . nor do i finde that there was any certain country called chaldaea ; though a town where any of them inhabited were called a town of the chaldies . martinius saith further , that the same word chasdim did signifie also demons . a. by this reckoning i should conjecture they were called chusdim , as being a race of ethiopians . for the land of chus is aethiopia ; and so the name degenerated first into chuldim , and then into chaldim ; so that they were such another kinde of people as we call gypsies ; saving that they were admired and feared for their knavery , and the gypsies counted rogues . b. nay pray , except claudius ptolomaeus , author of that great work of astronomy , the almegest . a. i grant he was excellent both in astronomy and geometry , and to be commended for his almegest ; but then for his judiciar astrologie annexed to it , he is again a gypsie . but the greeks that travelled ( you say ) into egypt , what philosophy did they carry home ? b. the mathematiques and astronomy . but for that sublunary physiques , which is commonly called natural philosophy , i have not read of any nation that studied it earlier than the greeks , from whom it proceeded to the romans . yet both greeks and romans were more addicted to moral than to natural philosophy ; in which kinde we have their writings , but loosly and incoherently , written upon no other principles than their own passions and presumptions , without any respect to the laws of common-wealth , which are the ground and measure of all true morality . so that their books tend rather to teach men to censure than to obey the laws . which has been a great hinderance to the peace of the western world ever since . but they that seriously applied themselves to natural philosophy were but few , as plato and aristotle , whose works we have ; and epicurus , whose doctrine we have in lucretius . the writings of philolaus and many other curious students being by fire or negligence now lost : though the doctrine of philolaus concerning the motion of the earth have been revived by copernicus , and explained and confirmed by galileo now of late . a. but methinks the natural philosophy of plato and aristotle , and the rest , should have been cultivated and made to flourish by their disciples . b. whom do you mean , the successors of plato , epicurus , aristotle , and the other first philosophers ? it may be some of them may have been learned and worthy men . but not long after , and down to the time of our saviour and his apostles , they were for the most part a sort of needy , ignorant , impudent cheating fellows , who by the profession of the doctrine of those first philosophers , got their living . for at that time , the name of philosophy was so much in fashion and honour amongst great persons , that every rich man had a philosopher of one sect or another to be a schoolmaster to his children . and these were they that faining christianity , with their disputing and readiness of talking got themselves into christian commons , and brought so many heresies into the primitive church , every one retaining still a tang of what they had been us'd to teach . a. but those heresies were all condemned in the first council of nice . b. yes . but the arrian heresie for a long time flourished no less than the roman , and was upheld by divers emperours , and never fully extinguished as long as there were vandals in christendom . besides , there arose daily other sects , opposing their philosophy to the doctrine of the councils concerning the divinity of our saviour ; as , how many persons he was , how many natures he had . and thus it continued till the time of charlemain , when he and pope leo the third divided the power of the empire into temporal and spiritual . a. a very unequal division . b. why ? which of them think you had the greater share ? a. no doubt , the emperour : for he onely had the sword. b. when the swords are in the hands of men , whether had you rather command the men or the swords ? a. i understand you . for he that hath the hands of the men , has also the use both of their swords and strength . b. the empire thus divided into spiritual and temporal , the freedom of philosophy was to the power spiritual very dangerous . and for that cause it behoved the pope to get schools set up not onely for divinity , but also for other sciences , especially for natural philosophy . which when by the power of the emperour he had effected , out of the mixture of aristotle's metaphysicks with the scripture , there arose a new science called school-divinity ; which has been the principal learning of these western parts from the time of charlemain till of very late . a. but i finde not in any of the writings of the school-men in what manner , from the causes they assigne , the effect is naturally and necessarily produced . b. you must not wonder at that . for you enquire not so much , when you see a change of any thing , what may be said to be the cause of it , as how the same is generated ; which generation is the entire progress of nature from the efficient cause to the effect produced . which is always a hard question , and for the most part impossible for a man to answer to . for the alterations of the things we perceive by our five senses are made by the motion of bodies ( for the most part ) either for distance , smalness , or transparence , invisible . a. but what need had they then to assigne any cause at all , seeing they could not shew the effect was to follow from it ? b. the schools ( as i said ) were erected by the pope and emperour , but directed by the pope onely , to answer and confute the heresies of the philosophers . would you have them then betray their profession and authority , that is to say , their livelihood , by confessing their ignorance ? or rather uphold the same , by putting for causes , strange and unintelligible words ; which might serve well enough not onely to satisfie the people whom they relied on , but also to trouble the philosophers themselves to finde a fault in . a. seeing you say that alteration is wrought by the motion of bodies , pray tell me first what i am to understand by the word body . b. it is a hard question , though most men think they can easily answer it , as that it is whatsoever they can see , feel , or take notice of by their senses . but if you will know indeed what is body , we must enquire first what there is that is not body . you have seen ( i suppose ) the effects of glasses , how they multiply and magnifie the object of our sight ; as when a glass of a certain figure will make a counter or a shilling seem twenty , though you be well assured there is but one . and if you set a mark upon it , you will finde the mark upon them all . the counter is certainly one of those things we call bodies : are not the others so too ? a. no , without doubt . for looking through a glass cannot make them really more than they are . b. what then be they but fancies , so many fancies of one and the same thing in several places ? a. 't is manifest they are so many idols , mere nothings . b. when you have look'd upon a star or candle with both your eyes , but one of them a little turn'd awry with your finger , has not there appeared two stars , or two candles ? and though you call it a deception of the sight , you cannot deny but there were two images of the object . a. 't is true , and observed by all men . and the same i say of our faces seen in looking-glasses , and of all dreams , and of all apparitions of dead mens ghosts ; and wonder , since 't is so manifest , i never thought upon 't before , for it is a very happy encounter , and such as being by every body well understood , would utterly destroy both idolatry and superstition , and defeat abundance of knaves that cheat and trouble the world with their devices . b. but you must not hence conclude that whosoever tells his dream , or sometimes takes his direction from it , is therefore an idolater , or superstitious , or a cheater . for god doth often admonish men by dreams of what they ought to do ; yet men must be wary in this case that they trust not dreams with the conduct of their lives further than by the laws of their country is allow'd : for you know what god says , deut. . if a prophet or a dreamer of dreams give thee a signe or a wonder , and the signe come to pass , yet if he did thee serve other gods , let him be put to death . here by serving other gods ( since they had chosen god for their king ) we are to understand revolting from their king , or disobeying of his laws . otherwise i see no idolatry nor superstition in following a dream , as many of the patriarches ( in the old testament ) and of the saints ( in the new testament ) did . a. yes : their own dreams . but when another man shall dream , or say that he has dream'd , and require me to follow that , he must pardon me if i ask him by what authority , especially if he look i should pay him for it . b. but if commanded by the laws you live under , you ought to follow it . but when there proceed from one sound divers echoes , what are those echoes ? and when with fingers cross'd you touch a small bullet , and think it two ; and when the same herb or flower smells well to one and ill to another , and the same at several times , well and ill to your self , and the like of tastes , what are those echoes , feelings , odours , and tastes ? a. 't is manifest they are all but fancies . but certainly when the sun seems to my eye no bigger than a dish , there is behinde it somewhere somewhat else ( i suppose a real sun ) which creates those fancies , by working ( one way or other ) upon my eyes , and other organs of my senses , to cause that diversity of fancy . b. you say right ; and that is it i mean by the word body , which briefly i define to be any thing that hath a being in it self , without the help of sense . a. aristotle ( i think ) meaneth by body , substance , or subjectum , wherein colour , sound , and other fancies are ( as he says ) inherent . for the word essence has no affinity with substance . and seneca says , he understands it not . and no wonder : for essence is no part of the language of mankinde , but a word devised by philosophers out of the copulation of two names , as if a man having two hounds could make a third ( if 't were need ) of ther● couples . b. 't is just fo . for having said in themselves ( for example ) a tree is a plant , and conceiving well enough what is the signification of those names , knew not what to make of the word is that couples those names ; nor daring to call it a body , they called it by a new name , ( derived from the word est ) essentia , and substantia , deceived by the idiome of their own language . for in many other tongues , and namely in the hebrew , there is no such copulative . they thought the names of things sufficiently connected , when they are placed in their natural consequence ; and were therefore never troubled with essences , nor other fallacy from the copulative est. cap. ii. of the principles and method of natural philosophy . a. this history of the old philosophers has not put me out of love , but out of hope of philosophy from any of their writings . i would therefore try if i could attain any knowledge therein by my own meditation : but i know neither where to begin , nor which way to proceed . b. your desire ( you say ) is to know the causes of the effects or phaenomena of nature ; and you confess they are fancies , and ( consequently ) that they are in your self ; so that the causes you seek for onely are without you , and now you would know how those external bodies work upon you to produce those phaenomena . the beginning therefore of your enquiry ought to be at what it is you call a cause , i mean an efficient cause : for the philosophers make four kindes of causes , whereof the efficient is one . another they call the formal cause , or simply the form or essence of the thing caused ; as when they say , four equal angles and four equal sides are the cause of a square figure , or that heaviness is the cause that makes heavie bodies to descend . but that 's not the cause you seek for , nor any thing but this : it descends because it descends . the third is the material cause , as when they say , the walls and roof , &c. of a house , are the cause of a house . the fourth is the final cause , and hath place onely in moral philosophy . a. we will think of final causes upon some other occasion ; of formal and material not at all : i seek onely the efficient , and how it acteth from the beginning to the production of the effect . b. i say then , that in the first place you are to enquire diligently into the nature of motion . for the variations of fancies , or ( which is the same thing ) of the phaenomena of nature , have all of them one universal efficient cause , namely the variety of motion . for if all things in the world were absolutely at rest , there could be no variety of fancy , but living creatures would be without sense of all objects , which is little less than to be dead . a. what if a childe new taken from the womb should with open eyes be exposed to the azure-sky , do not you think it would have some sense of the light , but that all would seem unto him darkness ? b. truly , if he had no memory of any thing formerly seen , or by any other sense perceived ( which is my supposition ) i think he would be in the dark . for darkness is darkness , whether it be black or blue , to him that cannot distinguish . a. howsoever that be , it is evident enough that whatsoever worketh is moved : for action is motion . b. having well considered the nature of motion , you must thence take your principles for the foundation and beginning of your enquiry . a. as how ? b. explain as fully and as briefly as you can what you constantly mean by motion ; which will save your self as well as others from being seduced by aequivocation . a. then i say , motion is nothing but change of place : for all the effect of a body upon the organs of our senses is nothing but fancy . therefore we can fancy nothing from seeing it moved , but change of place . b. 't is right . but you must then tell me also what you understand by place : for all men are not yet agreed on that . a. well then ; seeing we fancy a body , we cannot but fancy it somewhere . and therefore i think place is the fancy of here or there . b. that is not enough . here and there are not understood by any but your self , except you point towards it . but pointing is no part of a definition . besides , though it help him to finde the place , it will never bring him to it . a. but seeing sense is fancy , when we fancy a body , we fancy also the figure of it , and the space it fills up . and then i may define place to be the precise space within which the body is contained . for space is also part of the image we have of the object seen . b. and how define you time ? a. as place is to a body , so ( i think ) is time to the motion of it ; and consequently i take time to be our fancy or image of the motion . but is there any necessity of so much niceness ? b. yes . the want of it is the greatest , if not the onely cause , of all the discord amongst philosophers , as may easily be perceived by their abusing and confounding the names of things that differ in their nature ; as you shall see when there is occasion to recite some of the tenets of divers philosophers . a. i will avoid aequivocation as much as i can . and for the nature of motion , i suppose i understand it by the definition . what is next to be done ? b. you are to draw from these definitions , and from whatsoever truth else you know by the light of nature , such general consequences as may serve for axiomes , or principles of your ratiocination . a. that is hard to do . b. i will draw them my self , as many as for our present discourse of natural causes we shall have need of ; so that your part will be no more than to take heed i do not deceive you . a. i will look to that . b. my first axiome then shall be this : two bodies , at the same time , cannot be in one place . a. that 's true : for we number bodies as we fancy them distinct , and distinguish them by their places . you may therefore adde , nor one body at the same time in two places . and philosophers mean the same , when they say , there is no penetration of bodies . b. but they understand not their own words : for penetration signifies it not . my second axiome is , that nothing can begin , change , or put an end to its own motion . for supposing it begin just now , or being now in motion , change its way or stop ; i require the cause why now rather than before or after , having all that is necessary to such motion , change , or rest , alike at all times . a. i do not doubt but the argument is good in bodies inanimate ; but perhaps in voluntary agents it does not hold . b. how it holds in voluntary agents we will then consider when our method hath brought us to the powers and passions of the minde . a third axiome shall be this : whatsoever body being at rest is afterwards moved , hath for its immediate movent some other body which is in motion and toucheth it . for , since nothing can move it self , the movent must be external . and because motion is change of place , the movent must put it from its place , which it cannot do till it touch it . a. that is manifest , and that it must more than touch it , it must also follow it . and if more parts of the body are moved than are by the movent touched , the movent is not immediate . and by this reason , a continued body though never so great , if the first superficies be prest never so little back , the motion will proceed through it . b. do you think that to be impossible ? i will prove it from your own words : for you say that the movent does then touch the body which it moveth . therefore it puts it back ; but that which is put back , puts back the next behinde , and that again the next ; and so onward to any distance , the body being continued . the same is also manifest by experience , seeing one that walks with a staff can distinguish ( though blinde ) between stone and glass ; which were impossible , if the parts of his staff between the ground and his hand made no resistance . so also he that in the silence of the night lays his ear to the ground , shall hear the treading of mens feet further than if he stood upright . a. this is certainly true of a staff or other hard body , because it keeps the motion in a straight line from diffusion . but in such a fluid body as the air , which being put back must fill an orb , and the further it is put back , the greater orb , the motion will decrease , and in time , by the resistance of air to air , come to an end . b. that any body in the world is absolutely at rest , i think not true : but i grant , that in a space filled every where with body , though never so fluid , if you give motion to any part thereof , that motion will by resistance of the parts moved , grow less and less , and at last cease ; but if you suppose the space utterly void , and nothing in it , then whatsoever is once moved shall go on eternally : or else that which you have granted is not true , viz. that nothing can put an end to its own motion . a. but what mean you by resistance ? b. resistance is the motion of a body in a way wholly or partly contrary to the way of its movent , and thereby repelling or retarding it . as when a man runs swiftly , he shall feel the motion of the air in his face . but when two hard bodies meet , much more may you see how they abate each others motion , and rebound from one another . for in a space already full , the movent cannot , in an instant , be communicated through the whole depth of the body that is to be moved . a. what other definitions have i need of ? b. in all motion , as in all quantity , you must take the beginning of your reckoning from the least supposed motion . and this i call the first endeavour of the movent ; which endeavour , how weak soever , is also motion . for if it have no effect at all , neither will it do any thing though doubled , trebled , or by what number soever multiplied : for nothing , though multiplied , is still nothing . other axiomes and definitions we will take in , as we need them , by the way . a. is this all the preparation i am to make ? b. no , you are to consider also the several kinds and properties of motion , viz. when a body being moved by one or more movents at once , in what way it is carried , straight , circular , or otherwise crooked ; and what degree of swiftness ; as also the action of the movent , whether trusion , vection , percussion , reflexion , or refraction ; and further you must furnish your self with as many experiments ( which they call phaenomenon ) as you can . and supposing some motion for the cause of your phaenomenon , try if by evident consequence , without contradiction to any other manifest truth or experiment , you can derive the cause you seek for from your supposition . if you can , 't is all that is expected ( as to that one question ) from philosophy . for there is no effect in nature which the author of nature cannot bring to pass by more ways than one . a. what i want of experiments you may supply out of your own store , or such natural history as you know to be true ; though i can be well content with the knowledge of the causes of those things which every body sees commonly produced . let us therefore now enquire the cause of some effect particular . b. we will begin with that which is the most universal , the universe , and enquire in the first place , if any place be absolutely empty , that is to say in the language of philosophers , whether there be any vacuum in nature . cap. iii. of vacuum . a. 't is hard to suppose , and harder to believe that the infinite and omnipotent creator of all things should make a work so vast as is the world we see , and leave a few little spaces with nothing at all in them ; which put altogether in respect of the whole creature , would be insensible . b. why say you that ? do you think any argument can be drawn from it to prove there is vacuum ? a. why not ? for in so great an agitation of natural bodies , may not some small parts of them be cast out , and leave the places empty from whence they were thrown ? b. because he that created them is not a fancy , but the most real substance that is ; who being infinite , there can be no place empty where he is , nor full where he is not . a. 't is hard to answer this argument , because i do not remember that there is any argument for the maintenance of vacuum in the writings of divines : therefore i will quit that argument , and come to another . if you take a glass vial with a narrow neck , and having suckt it , dip it presently at the neck into a bason of water , you shall manifestly see the water rise into the vial. is not this a certain signe that you had suckt out some of the air , and consequently that some part of the vial was left empty ? b. no : for when i am about to suck , and have air in my mouth , contracting my cheeks i drive the same against the air in the glass , and thereby against every part of the sides of the hard glass . and this gives to the air within an endeavour outward , by which ( if it be presently dipt into the water ) it will penetrate and enter into it . for air if it be prest will enter into any fluid , much more into water . therefore there shall rise into the vial so much water as there was air forced into the bason . a. this i confess is possible , and not improbable . b. if sucking would make vacuum , what would become of those women that are nurses ? should they not be in a very few days exhausted , were it not that either the air which is in the childs mouth penetrateth the milk as it descends , and passeth through it , or the breast is contracted ? a. from what experiment can you evidently infer that there is no vacuum ? b. from many , and such as to almost all men are known and familiar . if two hard bodies , flat and smooth , be joyned together in a common superficies parallel to the horizontal plain , you cannot without great force pull them asunder , if you apply your force perpendicularly to the common superficies : but if you place that common superficies erect to the horizon , they will fall asunder with their own weight . from whence i argue thus : since their contiguity , in what posture soever , is the same , and that they cannot be pull'd asunder by a perpendicular force without letting in the ambient air in an instant , which is impossible ; or almost in an instant , which is difficult : and on the other side , when the common superficies is erect , the weight of the same hard bodies are able to break the contiguity , and let in the air successively , it is manifest that the difficulty of separation proceeds from this , that neither air nor any other body can be moved to any ( how small soever ) distance in an instant ; but may easily be moved ( the hardness at the sides once mastered ) successively . so that the cause of this difficulty of separation is this , that they cannot be parted except the air or other matter can enter and fill the space made by their diremption . and if they were infinitely hard , not at all . and hence also you may understand the cause why any hard body , when it is suddenly broken , is heard to crack ; which is the swift motion of the air to fill the space between . another experiment , and commonly known , is of a barrel of liquor , whose tap-hole is very little , and the bung so stopt as to admit no air ; for then the liquor will not run : but if the tap-hole be large it will , because the air prest by a heavier bodie will pierce through it into the barrel . the like reason holds of a gardeners watering-pot , when the holes in the bottom are not too great . a third experiment is this : turn a thin brass kettle the bottom upwards , and lay it flat upon the water . it will sink till the water rise within to a certain height , but no higher : yet let the bottom be perforated , and the kettle will be full and sink , and the air rise again through the water without . but if a bell were so laid on , it would be fill'd and sink , though it were not perforated , because the weight is greater than the weight of the same bulk of water . a. by these experiments , without any more , i am convinced , that there is not actually in nature any vacuum ; but i am not sure but that there may be made some little place empty , and this from two experiments , one whereof is torricellius his experiment , which is this : take a cylinder of glass , hollow throughout , but close at the end , in form of a sack. b. how long ? a. as long as you will , so it be more than inches . b. and how broad ? a. as broad as you will , so it be broad enough to pour into it quicksilver . and fill it with quicksilver , and stop up the entrance with your finger , so as to unstop it again at your pleasure . then set down a bason , or ( if you will ) a sea of quicksilver , and inverting the cylinder full as it is , dip the end into the quicksilver , and remove your finger , that the cylinder may empt it self . do you conceive me ? for there is so many passing by , that i cannot paint it . b. yes , i conceive you well enough . what follows ? a. the quicksilver will descend in the cylinder , not till it be level with that in the bason according to the nature of heavie fluids , but stay and stand above it at the height of inches or very neer it , the bottom being now uppermost that no air can get in . b. what do you infer from this ? a. that all the cavitie above inches is fill'd with vacuum . b. 't is very strange that i , from this same experiment , should infer ( and i think evidently ) that it is fill'd with air. i pray , tell me , when you had inverted the cylinder , full as it was , and stopt with your finger , dipt into the bason , if you had then removed your finger , whether you think the quicksilver would not all have fallen out ? a. no sure . the air would have been prest upward through the quicksilver it self : for a man with his hand can easily thrust a bladder of air to the bottom of a bason of quicksilver . b. it is therefore manifest that quicksilver can press the air through the same quicksilver . a. 't is manifest ; and also it self rise into the air. b. what cause then can there be , why it should stand still at inches above the level of the bason , rather than any place else ? a. 't is not hard to assigne the cause of that . for so much quicksilver as was above the inches , will raise the first level of that in the bason , as much as if you had pour'd it on ; and thereby bring it to an aequilibrium . so that i see plainly now , that there is no necessity of vacuum from this experiment . for i considered onely that naturally quicksilver cannot ascend in air , nor air descend in quicksilver , though by force it may . b. nor do i think that torricellius or any other vacuist thought of it more than you . but what is the second experiment ? a. there is a sphere of glass , which they call a recipient , of the capacity of three or four gallons . and there is inserted into it the end of a hollow cylinder of brass above a foot long ; so that the whole is one vessel , and the bore of the cylinder three inches diameter . into which is thrust by force a solid cylinder of wood , covered with leather so just , as it may in every point exactly touch the concave superficies of the brass . there is also to let out the air which the wooden cylinder as it enters ( called the sucker ) drives before it , a flap to keep out the external air while they are pulling the sucker . besides , at the top of the recipient there is a hole to put into it any thing for experiment . the sucker being now forc'd up into the cylinder , what do you think must follow ? b. i think it will require as much strength to pull it back , as it did to force it in . a. that is not it i ask , but what would happen to the recipient . b. i think so much air as would fill the place the sucker leaves , would descend into it out of the recipient ; and also that just so much from the external air would enter into the recipient , between the brass and the wood , at first very swiftly , but , as the place increased , more leasurely . a. why may not so much air rather descend into the place forsaken , and leave as much vacuum as that comes to , in the recipient ? for otherwise no air will be pumpt out ; nor can that wooden pestle be called a sucker . b. that 's it i say . there is no air either pumpt or sucked out . a. how can the air pass between the leather and the brass , or between the leather and the wood being so exactly contiguous , or through the leather it self ? b. i conceive no such exact contiguity , nor such fastness of the leather : for i never yet had any that in a storm would keep out either air or water . a. but how then could there be made in the recipient such strange alteration both on animate and inanimate bodies ? b. i will tell you how : the air descends out of the recipient , because the air which the sucker removeth from behinde it self as it is pulling out , has no place to retire into without . and therefore is driven into the engine between the wood of the sucker and the brass of the cylinder , and causes as much air to come into the place forsaken by the retiring sucker ; which causeth by oft repetition of the force , a violent circulation of the air within the recipient , which is able quickly to kill any thing that lives by respiration , and make all the alterations that have appeared in the engine . cap. iv. of the systeme of the world. b. you are come in good time ; let us therefore sit down . there is ink , paper , ruler , and compass . draw a little circle to represent the body of the sun. a. 't is done . the centre is a , the circumference is l m. b. upon the same centre a , draw a larger circle to stand for the ecliptick : for you know the sun is always in the plain of the ecliptick . a. there ' t is . the diameters of it at right angles are b z. b. draw the diameter of the aequator . a. how ? b. through the centre a ( for the earth is also always in the plain of the aequator or of some of its parallels ) so as to be distant from b deg . and a half . a. let it be h i : and let c g be equal to b h ; and so g will be one of the poles of the ecliptick , suppose the north-pole ; and then h will be east , and i west . and c a produced to the circumference in e , makes e the south-pole . b. take c k equal to c g , and the chord g k will be the diameter of the arctick-circle , and parallel to h i , the diameter of the aequator . lastly , upon the point b , draw a little circle wherein i suppose to be the globe of the earth . a. 't is drawn , and marked with l m. and b d and k g joyned will be parallel ; and as h and i are east and west , and so are b and d , and g and k. b. true ; but producing z b to the circumference l m in b , the line b b will be in the diameter of the ecliptick of the earth , and b m in the diameter of the aequator of the earth . in like manner , if you produce k g cutting the circle , whose centre is g , in d and e , and make an angle n g d equal to b b m , the line n g will be in the ecliptick of the earth , because g d is in the aequator of the earth . so that in the annual motion of the earth through the ecliptick , every streight line drawn in the earth , is perpetually kept parallel to the place from whence it is removed . a. 't is true ; and 't is the doctrine of copernicus . but i cannot yet conceive by what one motion this circle can be described otherwise than we are taught by euclid . and then i am sure that all the diameters shall cross one another in the centre , which in this figure is a. b. i do not say that the diameters of a sphere or circle can be parallel ; but that if a circle of a lesser sphere be moved upon the circumference of a great circle of a greater sphere , that the streight lines that are in the lesser sphere may be kept parallel perpetually to the places they proceed from . a. how ? and by what motion ? b. take into your hand any streight line , ( as in this figure ) the line l a m , which we suppose to be the diameter of the suns body ; and moving it parallelly , with the ends in the circumference , so as that the end m may withal describe a small circle , as m a. it is manifest that all the other points of the same line l m will by the same motion , at the same time , describe equal circles to it . likewise if you take in your hand any two diameters fastened together , the same parallel-motion of the line l m , shall cause all the points of the other diameter to make equal circles to the same m a. a. 't is evident ; as also that every point of the suns body shall do the like . and not onely so , but also if one end describe any other figure , all the other points of the body shall describe like and equal figures to it . b. you see by this , that this parallel-motion is compounded of two motions , one circular upon the superficies of a sphere , the other a streight motion from the centre to every point of the same superficies , and beyond it . a. i see it . b. it follows hence , that the sun by this motion must every way repel the air ; and since there is no empty place for retiring , the air must turn about in a circular stream ; but slower or swifter according as it is more or less remote from the sun , and that according to the nature of fluids , the particles of the air must continually change place with one another ; and also that the stream of the air shall be the contrary way to that of the motion , for else the air cannot be repelled . a. all this is certain . b. well . then if you suppose the globe of the earth to be in this stream which is made by the motion of the suns body from east to west , the stream of air wherein is the earths annual motion will be from west to east . a. 't is certain . b. well . then if you suppose the globe of the earth , whose circle is moved annually , to be l m , the stream of the air without the ecliptick falling upon the superficies of the earth l m without the ecliptick , being slower , and the stream that falleth within swifter , the earth shall be turned upon its own centre proportionally to the greatness of the circles ; and consequently their diameters shall be parallel ; as also are other streight lines correspondent . a. i deny not but the streams are as you say ; and confess that the proportion of the swiftness without , is to the swiftness within , as the suns ecliptick to the ecliptick of the earth ; that is to say , as the angle hab to the angle m b b. and i like your argument the better , because it is drawn from copernicus his foundation . i mean the compounded motion of streight and circular . b. i think i shall not offer you many demonstrations of physical conclusions that are not derived from the motions supposed or proved by copernicus . for those conclusions in natural philosophy i most suspect of falshood , which require most variety of suppositions for their demonstrations . a. the next thing i would know , is how great or little you suppose that circle a m. b. i suppose it less than you can make it : for there appears in the sun no such motion sensible . 't is the first endeavour of the suns motion . but for all that , as small as the circle is , the motion may be as swift , and of as great strength as 't is possible to be named . 't is but a kinde of trembling that necessarily happeneth in those bodies , which with great resistance press upon one another . a. i understand now from what cause proceedeth the annual motion : is the sun the cause also of the diurnal motion ? b. not the immediate cause . for the diurnal motion of the earth is upon its own centre , and therefore the suns motion cannot describe it . but it proceedeth as a necessary consequence from the annual motion . for which i have both experience and demonstration . the experiment is this : into a large hemisphere of wood , spherically concave , put in a globe of lead , and with your hands hold it fast by the brim , moving your hands circularly , but in a very small compass , you shall see the globe circulate about the concave vessel , just in the same manner as the earth doth every year in the air ; and you shall see withal , that as it goes , it turns perpetually upon its own centre , and very swiftly . a. i have seen it : and 't is used in some great kitchins to grinde mustard . b. is it so ? therefore take a hemisphere of gold ( if you have it ) the greater the better , and a bullet of gold , ( and without mustard ) you shall see the same effect . a. i doubt it not . but the of it cause is evident . for any spherical body being in motion upon the sides of a concave and hard sphere , is all the way turned upon its own centre by the resistance of the hard wood or metal . but the earth is a bullet without weight , and meeteth onely with air , without any harder body in the way to resist it . b. do you think the air makes no resistance , especially to so swift a motion as is the annual motion of the earth ? if it do make any resistance , you cannot doubt but that it shall turn the earth circularly , and in a contrary way to its annual motion ; that is to say , from east to west , because the annual motion is from west to east . a. i confess it . but what deduce you from these motions of the sun ? b. i deduce ( first ) that the air must of necessity be moved both circularly about the body of the sun according to the ecliptick , and also every way directly from it . for the motion of the suns body is compounded of this circular motion upon the sphere l m , and of the streight motion of its semi-diameters from the centre a to the superficies of the suns body , which is lm . and therefore the air must needs be repelled every way , and also continually change place to fill up the places forsaken by other parts of the air , which else would be empty , there being no vacuum to retire unto . so that there would be a perpetual stream of air , and in a contrary way to the motion of the suns body , such as is the motion of water by the sides of a ship under sail . a. but this motion of the earth from west to east , is onely circular , such as is described by a compass about a centre ; and cannot therefore repel the air as the sun does . and the disciples of copernicus will have it to be the cause of the moons monthly motion about the earth . b. and i think copernicus himself would have said the same , if his purpose had been to have shewn the natural causes of the motions of the stars . but that was no part of his designe ; which was onely from his own observations , and those of former astronomers , to compute the times of their motions ; partly to foretel the conjunctions , oppositions , and other aspects of the planets ; and partly to regulate the times of the churches festivals . but his followers , kepler and galileo , make the earths motion to be the efficient cause of the monthly motion of the moon about the earth ; which without the like motion to that of the sun in lm , is impossible . let us therefore for the present take it in as a necessary hypothesis ; which from some experiment that i shall produce in our following discourses , may prove to be a certain truth . a. but seeing a is the centre both of the suns body and of the annual motion of the earth , how can it be ( as all astronomers say it is ) that the orb of the annual motion of the earth should be excentrique to the suns body ? for you know that from the vernal aequinox to the autumnal , there be days ; but from the autumnal aequinox to the vernal , there be but days . what natural cause can you assigne for this excentricity ? b. kepler ascribes it to a magnetique vertue , viz. that one part of the earths superficies has a greater kindness for the sun than the other part . a. i am not satisfied with that . it is magical rather than natural , and unworthy of kepler . tell me your own opinion of it . b. i think that the magnetical vertue he speaks of , consisteth in this : that the southern hemisphere of the earth is for the greatest part sea , and that the greatest part of the northern hemisphere is dry land. but how it is possible that from thence should proceed the excentricity ( the sun being neerest to the earth , when he is in the winter-solstice ) i shall shew you when we come to speak of the motions of air and water . a. that 's time enough : for i intend it for our next meeting . in the mean time i pray you tell me what you think to be the cause why the equinoctial ( and consequently the solstitial ) points are not always in one and the same point of the ecliptique of the fixt stars . i know they are not , because the sun does not rise and set in points diametrally opposite : for if it did , there would be no difference of the seasons of the year . b. the cause of that can be no other , than that the earth ( which is l m ) hath the like motion to that which i suppose the sun to have in l m , compounded of streight and circular from west to east in a day , as the annual motion hath in a year ; so that ( not reckoning the excentricity ) it will be moved through the ecliptiques one revolution ( as copernicus proveth ) about one degree . suppose then the whole earth moved from h to i , ( which is half the year ) circularly , but falling from i to i in the same time about minutes , and as much in the other hemisphere from h to k ; then draw the line i k , which will be equal and parallel to h i , and be the diameter of the aequator for the next year . but it shall not cut the diameter of the ecliptick b z in a , which was the equinoctial of the former year , but in o seconds from the first degree of aries . suppose the same done in the hemisphere under the plain of the paper , and so you have the double of seconds , that is seconds , or very neer , for the progress of the vernal equinox in a year . the cause why i suppose the arch i i to be half a degree in the ecliptique of the earth , is , that copernicus and other astronomers , and experience , agree in this , that the aequinoctial points proceed according to the order of the signes , aries , taurus , gemini , &c. from west to east every year one degree or very neer . a. in what time do they make the whole revolution through the ecliptique of the sky ? b. that you may reckon . for we know by experience that it hath proceeded about one degree , that is minutes constantly a long time in a hundred years . but as years to one degree , so is years to degrees . also as years to one degree , so is one year to the hundred part of one degree or minutes ; which is / , or seconds for the progress of one year ; which must be somewhat more than a degree according to copernicus , who , lib. . cap. . saith , that for years before ptolomie it was one degree almost constantly . which is well enough as to the natural cause of the precession of the aequinoctial points , which is the often-said compounded motion , though not an exact astronomical calculation . a. and 't is a great signe that his supposition is true . but what is the cause that the obliquity of the ecliptique , that is , the distance between the aequinoctial and the solstice , is not always the same ? b. the necessity of the obliquity of the ecliptique is but a consequence to the precession of the aequinoctial points . and therefore if from c the north-pole you make a little circle c u equal to minutes of a degree upon the earth , and another u s equal to the same , which will appear like this figure , that is ( as copernicus calls it ) a circle twined , the pole c will be moved half the time of the aequinoctial points , in the arc c u , and as much in the alternate arc u s descending to s. but in the arc s u , and its alternate rising to c. the cause of the twining is the earths annual motion the same way in the ecliptique , and makes the four quarters of it ; and makes also their revolution twice as slow as that of the aequinoctial points . and therefore the motion of it is the same compounded motion which copernicus takes for his supposition , and is the cause of the precession of the aequinoctial points , and consequently of the variation of the obliquity , adding to it or taking from it somewhere more , somewhere less ; so as that one with another the addition is not much more , nor the substraction much less than minutes . but as for the natural efficient cause of this compounded motion , either in the sun , or the earth , or any other natural body , it can be none but the immediate hand of the creator . a. by this it seems that the poles of the earth are always the same , but make this in the sphere of the fixt stars neer that which is called cynosura . b. no : 't is described on the earth , but the annual motion describes a circle in the sphere of the fixed stars . though i think it improper to say a sphere of the fixt stars , when 't is so unlikely that all the fixt stars should be in the superficies of one and the same globe . a. i do not believe they are . b. nor i , since they may seem less one than another , as well by their different distances , as by their different magnitudes . nor is it likely that the sun ( which is a fixt star ) is the efficient cause of the motion of those remoter planets , mars , jupiter , and saturn ; seeing the whole sphere , whose diameter is the distance between the sun and the earth , is but a point in respect of the distance between the sun and any other fixed star. which i say onely to excite those that value the knowledge of the cause of comets , to look for it in the dominion of some other sun than that which moveth the earth . for why may not there be some other fixed star , neerer to some planet than is the sun , and cause such a light in it as we call a comet ? a. as how ? b. you have seen how in high and thin clouds above the earth , the sun-beams piercing them have appeared like a beard ; and why might not such a beard have appeared to you like a comet , if you had lookt upon it from as high as some of the fixed stars ? a. but because it is a thing impossible for me to know , i will proceed in my own way of enquiry . and seeing you ascribe this compounded motion to the sun and earth , i would grant you that the earth ( whose annual motion is from west to east ) shall give the moon her monthly-motion from east to west . but then i ask you whether the moon have also that compounded motion of the earth , and with it a motion upon its own centre , as hath the earth ? for seeing the moon has no other planet to carry about her , she needs it not . b. i see reason enough , and some necessity , that the moon should have both those motions . for you cannot think that the creator of the stars , when he gave them their circular motion , did first take a centre , and then describe a circle with a chain or compass , as men do ? no ; he moved all the parts of a star together and equally in the creation : and that 's the reason i give you . the necessity of it , comes from this phaenomenon , that the moon doth turn one and the same face towards the earth : which cannot be by being moved about the earth parallelly , unless also it turn about its own centre . besides , we know by experience , that the motion of the moon doth adde not a little to the motion of the sea : which were impossible if it did not adde to the stream of the air , and by consequence to that of the water . a. if you could get a piece of the true and intimate substance of the earth , of the bigness of a musquet-bullet , do you believe that the bullet would have the like compounded motion to that which you attribute to the sun , earth , and moon ? b. yes truly ; but with less strength , according to its magnitude ; saving that by its gravity falling to the earth , the activity of it would be unperceived . a. i will trouble you no more with the nature of celestial appearances . but i pray you tell me by what art a man may finde what part of a circle the diameter of the suns body doth subtend in the ecliptique circle . b. kepler says it subtends minutes , which is half a degree . his way to finde it is by letting in the sun-beams into a close room through a small hole , and receiving the image of it upon a plain perpendicularly . for by this means he hath a triangle , whose sides and angles he can know by measure ; and the vertical angle he seeks for , and the substance of the arc of the suns body . a. but i think it impossible to distinguish where the part illuminate toucheth the part not illuminate . b. another way is this : upon the aequinoctial-day , with a watch that shews the minutes standing by you , observe when the lower brim of the suns setting first comes to the horizon , and set the index to some minute of the watch ; and observe again the upper brim when it comes to the horizon : then count the minutes , and you have what you look for . other way i know none . cap. v. of the motions of water and air. a. i have considered , as you bad me , this compounded motion with great admiration . first , it is that which makes the difference between continuum and contiguum , which till now i never could distinguish . for bodies that are but contiguous , with any little force are parted ; but by this compounded motion ( because every point of the body makes an equal line in equal time , and every line crosses all the rest ) one part cannot be separated from another , without disturbing the motion of all the other parts at once . and is not that the cause , think you , that some bodies when they are prest or bent , as soon as the force is removed , return again of themselves to their former figure ? b. yes sure ; saving that it is not of themselves that they return , ( for we were agreed that nothing can move it self ) but it is the motion of the parts which are not prest , that delivers those that are . and this restitution the learned now call the spring of a body . the greeks called it antitypia . a. when i considered this motion in the sun and the earth and planets , i fancied them as so many bodies of the army of the almighty in an immense field of air , marching swiftly , and commanded ( under god ) by his glorious officer the sun , or rather forced so to keep their order in every part of every of those bodies , as never to go out from the distance in which he had set them . b. but the parts of the air and other fluids keep not their places so . a. no. you told me that this motion is not natural in the air , but received from the sun. b. true. but since we seek the natural causes of sublunary effects , where shall we begin ? a. i would fain know what makes the sea to ebbe and flow at certain periods , and what causeth such variety in the tides . b. remember that the earth turneth every day upon its own axis from west to east ; and all the while it so turneth , every point thereof by its compounded motion makes other circlings , but not on the same centre , which is ( you know ) a rising in one part of the day , and a falling in the other part . what think you must happen to the sea , which resteth on it , and is a fluid body ? a. i think it must make the sea rise and fall . and the same happeneth also to the air , from the motion of the sun. b. remember also , in what manner the sea is situated in respect of the dry land. a. is not there a great sea that reacheth from the straight of magellan eastward to the indies , and thence to the same straight again ? and is not there a great sea called the atlantick sea that runneth northward to us ? and does not the great south-sea run also up into the northern seas ? but i think the indian and the south-sea of themselves to be greater than all the rest of the surface of the globe . b. how lieth the water in those two seas ? a. east and west , and rises and falls a little , as it is forc'd to do by this compounded motion , which is a kind of succussion of the earth , and fills both the atlantick and northern seas . b. all this would not make a visible difference between high and low water , because this motion being so regular , the unevenness would not be great enough to be seen . for though in a bason the water would be thrown into the air , yet the earth cannot throw the sea into the air. a. yes . the bason , if gently moved , will make the water so move , that you shall hardly see it rise . b. it may be so . but you should never see it rise as it doth , if it were not checkt . for at the straight of magellan , the great south-sea is checkt by the shore of the continent of peru and chily , and forced to rise to a great height , and made to run up into the northern seas on that side by the coast of china ; and at the return is checkt again and forced through the atlantick into the british and german seas . and this is done every day . for we have supposed that the earths motion in the ecliptique caused by the sun is annual ; and that its motion in the aequinoctial , is diurnal . it followeth therefore from this compounded motion of the earth , the sea must ebb and flow twice in the space of twenty four hours , or thereabout . a. has the moon nothing to do in this business ? b. yes . for she hath also the like motion . and is , though less swift , yet much neerer to the earth . and therefore when the sun and moon are in conjunction or opposition , the earth , as from two agents at once , must needs have a greater succussion . and if it chance at the same time the moon also be in the ecliptique , it will be yet greater , because the moon then worketh on the earth less obliquely . a. but when the full or new moon happen to be then when the earth is in the aequinoctial points , the tides are greater than ordinary . why is that ? b. because then the force by which they move the sea , is at that time , to the force by which they move the same at other times , as the aequinoctial circle to one of its parallels , which is a lesser circle . a. 't is evident . and 't is pleasant to see the concord of so many and various motions , when they proceed from one and the same hypothesis . but what say you to the stupendious tides which happen on the coasts of lincolnshire on the east , and in the river of severn on the west ? b. the cause of that , is their proper scituation . for the current of the ocean through the atlantick sea , and the current of the south-sea through the northern seas meeting together , raise the water in the irish and british seas a great deal higher than ordinary . therefore the mouth of the severn being directly opposite to the current from the atlantick sea , and those sands on the coast of lincolnshire directly opposite to the current of the german sea , those tides must needs fall furiously into them , by this succussion of the water . a. does , when the tide runs up into a river , the water all rise together , and fall together when it goes out ? no : one part riseth and another falleth at the same time ; because the motion of the earth rising and falling , is that which makes the tide . a. have you any experiment that shews it ? b. yes . you know that in the thames , it is high water at greenwich before it is high water at london-bridge . the water therefore falls at greenwich whilst it riseth all the way to london . but except the top of the water went up , and the lower part downward , it were impossible . a. 't is certain . it is strange that this one motion should salve so many apparences , and so easily . but i will produce one experiment of water , not in the sea , but in a glass . if you can shew me that the cause of it is this compounded motion , i shall go neer to think it the cause of all other effects of nature hitherto disputed of . the experiment is common , and described by the lord chancellour bacon , in the third page of his natural history . take ( saith he ) a glass of water , and draw your finger round about the lip of the glass , pressing it somewhat hard ; after you have done so a few times , it will make the water frisk up into a fine dew . after i had read this , i tried the same with all diligence my self , and found true not onely the frisking of the water to above an inch high , but also the whole superficies to circulate , and withal to make a pleasant sound . the cause of the frisking he attributes to a tumult of the inward parts of the substance of the glass striving to free it self from the pressure . b. i have tried and found both the sound and motion ; and do not doubt but the pressure of the parts of the glass was part of the cause . but the motion of my finger about the glass was always parallel ; and when it chanced to be otherwise , both sound and motion ceased . a. i found the same . and being satisfied , i proceed to other questions . how is the water ( being a heavie body ) made to ascend in small particles into the air , and be there for a time sustained in form of a cloud , and then fall down again in rain ? b. i have shewn already , that this compounded motion of the sun , in one part of its circumlation , drives the air one way , and in the other part , the contrary way ; and that it cannot draw it back again , no more than he that sets a stone a flying can pull it back . the air therefore , which is contiguous to the water , being thus distracted , must either leave a vacuum , or else some part of the water must rise and fill the spaces continually forsaken by the air. but , that there is no vacuum , you have granted . therefore the water riseth into the air , and maketh the clouds ; and seeing they are very small and invisible parts of the water , are ( though naturally heavie ) easily carried up and down with the wind , till , meeting with some mountain or other clouds , they be prest together into greater drops , and fall by their weight . so also it is forced up in moist ground , and with it many small atomes of the earth , which are either twisted with the rising water into plants , or are carried up and down in the air incertainly . but the greatest quantity of water is forced up from the great south and indian seas , that lie under the tropique of capricorn . and this climate is that which makes the suns perigaeum to be always on the winter-solstice . and that is the part of the terrestrial globe which keplerus says is kinde to the sun ; whereas the other part of the globe ( which is almost all dry land ) has an antipathy to the sun. and so you see where this magnetical vertue of the earth lies . for the globe of the earth having no natural appetite to any place , may be drawn by this motion of the sun a little neerer to it , together with the water which it raiseth . a. can you guess what may be the cause of wind ? b. i think it manifest that the unconstant winds proceed from the uncertain motion of the clouds ascending and descending , or meeting with one another . for the winds after they are generated in any place by the descent of a cloud , they drive other clouds this way and that way before them , the air seeking to free it self from being pent up in a straight . for when a cloud descendeth , it makes no wind sensible directly under it self . but the air between it and the earth is prest and forced to move violently outward . for it is a certain experiment of mariners , that if the sea go high when they are becalmed , they say they shall have more wind than they would ; and take in their sails all but what is necessary for steering . they know ( it seems ) that the sea is moved by the descent of clouds at some distance off : which presseth the water , and makes it come to them in great waves . for a horizontal wind does but curl the water . a. from whence come the rivers ? b. from the rain , or from the falling of snow on the higher ground . but when it descendeth under ground , the place where it again ariseth is called the spring . a. how then can there be a spring upon the top of a hill ? b. there is no spring upon the very top of a hill , unless some natural pipe bring it thither from a higher hill. a. julius scaliger says , there is a river , and in it a lake , upon the top of mount cenis in savoy ; and will therefore have the springs to be ingendred in the caverns of the earth by condensation of the air. b. i wonder he should say that . i have pass'd over that hill twice since the time i read that in scaliger , and found that river as i pass'd , and went by the side of it in plain ground almost two miles . where i saw the water from two great hills , one on one side , the other on the other , in a thousand small rillets of melting snow fall down into it . which has made me never to use any experiment the which i have not my self seen . as for the conversion of air into water by condensation , and of water into air by rarefaction ( though it be the doctrine of the peripatetiques ) it is a thing incogitable , and the words are insignificant . for by densum is signified onely frequencie and closeness of parts ; and by rarum the contrary . as when we say a town is thick with houses , or a wood with trees , we mean not that one house or tree is thicker than another , but that the spaces between are not so great . but ( since there is no vacuum ) the spaces between the parts of air are no larger than between the parts of water , or of any thing else . a. what think you of those things which mariners that have sailed through the atlantick sea called spouts , which pour down water enough at once to drown a great ship ? b. 't is a thing i have not seen . and therefore can say nothing to it ; though i doubt not but when two very large and heavie clouds shall be driven together by two great and contrary winds , the thing is possible . a. i think your reason good . and now will propound to you another experiment . i have seen an exceeding small tube of glass with both ends open set upright in a vessel of water , and that the superficies of the water within the tube was higher a good deal than of that in the vessel ; but i see no reason for it . b. was not part of the glass under water ? must not then the water in the vessel rise ? must not the air that lay upon it rise with it ? whither should this rising air go , since there is no place empty to receive it ? it is therefore no wonder if the water , press'd by the substance of the glass which is dipt into it , do rather rise into a very small pipe , than come about a longer way into the open air. a. 't is very probable . i observed also that the top of the inclosed water was a concave superficies ; which i never saw in other fluids . b. the water hath some degree of tenacity , though not so great but that it will yield a little to the motion of the air ; as is manifest in the bubbles of water , where the concavity is always towards the air. and this i think the cause why the air and water meeting in the tube make the superficies towards the air concave , which it cannot do to a fluid of greater tenacity . a. if you put into a bason of water a long rag of cloth , first drenched in water , and let the longer part of it hang out , it is known by experience , that the water will drop out as long as there is any part of the other end under water . b. the cause of it is , that water ( as i told you ) hath a degree of tenacity . and therefore being continued in the rag till it be lower without than within , the weight will make it continue dropping , though not onely because it is heavie ( for if the rag lay higher without than within , and were made heavier by the breadth , it would not descend ) but 't is because all heavie bodies naturally descend with proportion of swiftness duplicate to that of the time ; whereof i shall say more when we talk of gravity . a. you see how despicable experiments i trouble you with . but i hope you will pardon me . b. as for mean and common experiments , i think them a great deal better witnesses of nature , than those that are forced by fire , and known but to very few . cap. vi. of the causes and effects of heat and cold. a. 't is a fine day , and pleasant walking through the fields , but that the sun is a little too hot . b. how know you that the sun is hot ? a. i feel it . b. that is to say , you know that your self , but not that the sun is hot . but when you finde your self hot , what body do you feel ? a. none . b. how then can you infer your heat from the sense of feeling ? your walking may have made you hot : is motion therefore hot ? no. you are to consider the concomitants of your heat ; as , that you are more faint , or more ruddy , or that you sweat , or feel some endeavour of moisture or spirits tending outward ; and when you have found the causes of those accidents , you have found the causes of heat , which in a living creature , and specially in a man , is many times the motion of the parts within him , such as happen in sickness , anger , and other passions of the minde ; which are not in the sun nor in fire . a. that which i desire now to know , is what motions and of what bodies without me are the efficient causes of my heat . b. i shewed you yesterday in discoursing of rain , how by this compounded motion of the suns body , the air was every way at once thrust off west and east ; so that where it was contiguous , the small parts of the water were forced to rise , for the avoiding of vacuum . think then that your hand were in the place of water so exposed to the sun. must not the sun work upon it as it did upon the water ? though it break not the skin , yet it will give to the inner fluids and looser parts of your hand , an endeavour to get forth , which will extend the skin , and in some climates fetch up the bloud , and in time make the skin black . the fire also will do the same to them that often sit with their naked skins too neer it . nay , one may sit so neer ( without touching it ) as it shall blister or break the skin , and fetch up both spirits and bloud mixt into a putrid oyly matter sooner , than in a furnace oyl can be extracted out of a plant. a. but if the water be above the fire in a kettle , what then will it do ? shall the particles of water go toward the fire , as it did toward the sun ? b. no. for it cannot . but the motion of the parts of the kettle which are caused by the fire , shall dissipate the water into vapour till it be all cast out . a. what is that you call fire ? is it a hard or fluid body ? b. it is not any other body but that of the shining coal ; which coal , though extinguished with water , is still the same body . so also in a very hot furnace , the hollow spaces between the shining coals , though they burn that you put into them , are no other body than air moved . a. is it not flame ? b. no. for flame is nothing but a multitude of sparks , and sparks are but the atomes of the fewel dissipated by the incredible swift motion of the movent , which makes every spark to seem a hundred times greater than it is , as appears by this ; that when a man swings in the air a small stick fired at one end ( though the motion cannot be very swift ) yet the fire will appear to the eye to be a long , streight , or crooked line . therefore a great many sparks together flying upward , must needs appear unto the sight as one continued flame . nor are the sparks striken out of a flint any thing else but small particles of the stone , which by their swift motion are made to shine . but that fire is not a substance of it self , is evident enough by this , that the sun-beams passing through a globe of water will burn as other fire does . which beams , if they were indeed fire , would be quenched in the passage . a. this is so evident , that i wonder so wise men as aristotle and his followers , for so long a time could hold it for an element , and one of the primary parts of the universe . but the natural heat of a man or other living creature , whence proceedeth it ? is there any thing within their bodies that hath this compounded motion ? b. at the breaking up of a deer i have seen it plainly in his bowels as long as they were warm . and it is called the peristaltique motion , and in the heart of a beast newly taken out of his body ; and this motion is called systole and diastole . but they are both of them this compounded motion , whereof the former causeth the food to winde up and down through the guts , and the later makes the circulation of the blood. a. what kind of motion is the cause of cold ? methinks it should be contrary to that which causeth heat . b. so it is in some respect . for seeing the motion that begets heat , tendeth to the separation of the parts of the body whereon it acteth , it stands with reason , that the motion which maketh cold , should be such as sets them closer together . but contrary motions are ( to speak properly ) when upon two ends of a line two bodies move towards each other , the effect whereof is to make them meet . but each of them ( as to this question ) is the same . a. do you think ( as many philosophers have held and now hold ) that cold is nothing but a privation of heat ? b. no. have you never heard the fable of the satyre that dwelling with a husbandman , and seeing him blow his fingers to warm them , and his pottage to cool it , was so scandalized , that he ran from him , saying he would no longer dwell with one that could blow both hot and cold with one breath ? yet the cause is evident enough . for the air which had gotten a calefactive power from his vital parts , was from his mouth and throat gently diffused on his fingers , and retained still that power . but to cool his pottage he streightened the passage at his lips , which extinguished the calefactive motion . a. do you think wind the general cause of cold ? if that were true , in the greatest winds we should have the greatest frosts . b. i mean not any of those uncertain winds which , i said , were made by the clouds , but such as a body moved in the air makes to and against it self . for it is all one motion of the air , whether it be carried against the body , or the body against it . such a wind as is constant ( if no other be stirring ) from east to west made by the earth turning dayly upon its own centre . which is so swift , as ( except it be kept off by some hill ) to kill a man , as by experience hath been found by those who have passed over great mountains , and specially over the andies which are opposed to the east . and such is the wind which the earth maketh in the air by her annual motion , which is so swift , as that ( by the calculation of astronomers ) to go sixty miles in a minute of an hour . and therefore this must be the motion which makes it so cold about the poles of the ecliptique . a. does not the earth make the wind as great in one part of the ecliptique as in another ? b. yes . but when the sun is in cancer , it tempers the cold , and still less and less , but least of all in the winter-solstice , where his beams are most oblique to the superficies of the earth . a. i thought the greatest cold had been about the poles of the aequator . b. and so did i once . but the reason commonly given for it is so improbable , that i do not think so now . for the cause they render of it , is onely , that the motion of the earth is swiftest in the aequinoctial , and slowest about the poles ; and consequently ( since motion is the cause of heat , and cold is but ( as 't was thought ) a want of the same ) they inferr'd that the greatest cold must be about the poles of the aequinoctial . wherein they miscounted . for not every motion causeth heat , but this agitation onely , which we call compounded motion ; though some have alleadged experience for that opinion ; as that a bullet out of a gun will with its own swiftness melt . which i never shall believe . a. 't is a common thing with many philosophers to maintain their fancies with any rash report , and sometimes with a lye. but how is it possible that so soft a substance as water should be turned into so hard a substance as ice ? b. when the air shaves the globe of the earth with such swiftness , as that of sixty miles in a minute of an hour , it cannot ( where it meets with still water ) but beat it up into small and undistinguishable bubbles , and involve it self in them as in so many bladders or skins of water . and ice is nothing else but the smallest imaginable parts of air and water mixt ; which is made hard by this compounded motion , that keeps the parts so close together , as not to be separated in one place without disordering the motion of them all . for when a body will not easily yield to the impression of an external movent in one place without yielding in all , we call it hard ; and when it does , we say 't is soft . a. why is not ice as well made in a moved as in a still water ? are there not great seas of ice in the northern parts of the earth ? b. yes , and perhaps also in the southern parts . but i cannot imagine how ice can be made in such agitation as is always in the open sea made by the tides and by the winds . but how it may be made at the shoar , it is not hard to imagine . for in a river or current , though swift , the water that adhereth to the banks is quiet , and easily by the motion of the air driven into small insensible bubbles ; and so may the water that adhereth to those bubbles , and so forwards till it come into a stream that breaks it , and then it is no wonder though the fragments be driven into the open sea , and freeze together into greater lumps . but when in the open sea , or at the shoar , the tide or a great wave shall arise , this young and tender ice will presently be washt away . and therefore i think it evident , that as in the thames the ice is first made at the banks where the tide is weak or none , and broken by the stream comes down to london , and part goes to the sea floating till it dissolve , and part ( being too great to pass the bridge ) stoppeth there and sustains that which follows , till the river be quite frozen over : so also the ice in the northern seas begins first at the banks of the continent and islands which are scituated in that climate , and then broken off , are carried up and down , and one against another , till they become great bodies . a. but what if there be islands , and narrow inlets of the sea , or rivers also about the pole of the aequinoctial ? b. if there be , 't is very likely the sea may also there be covered all over with ice . but for the truth of this , we must stay for some further discovery . a. when the ice is once made and hard , what dissolves it ? b. the principal cause of it , is the weight of the water it self ; but not without some abatement in the stream of the air that hardned it ; as when the sun-beams are less oblique to the earth , or some contrary wind resisteth the stream of the air. for when the impediment is removed , then the nature of the water only worketh , and ( being a heavie body ) downward . a. i forgot to ask you , why two pieces of wood rub'd swiftly one against another , will at length set on fire . b. not onely at length , but quickly , if the wood be dry . and the cause is evident , viz. the compounded motion which dissipates the external small parts of the wood. and then the inner parts must of necessity ( to preserve the plenitude of the universe ) come after ; first the most fluid , and then those also of greater consistence , which are first erected , and ( the motion continued ) made to flie swiftly out ; whereby the air driven to the eye of the beholder , maketh that fancie which is called light. a. yes . i remember you told me before , that upon any strong pressure of the eye , the resistance from within would appear a light. but to return to the enquiry of heat and cold , there be two things that beyond all other put me into admiration . one is the swiftness of kindling in gunpowder . the other is the freezing of water in a vessel ( though not far from the fire ) set about with other water with ice and snow in it . when paper or flax is flaming , the flame creeps gently on ; and if a house full of paper were to be burnt with putting a candle to it , it will be long in burning ; whereas a spark of fire would set on flame a mountain of gunpowder in almost an instant . b. know you not gunpowder is made of the powder of charcole , brimstone , and salt-peter ? whereof the first will kindle with a spark , the second flame as soon as toucht with fire ; and the third blows it , as being composed of many orbs of salt fill'd with air , and as it dissolveth in the flame , furiously blowing increaseth it . and as for making ice by the fire side . it is manifest that whilst the snow is dissolving in the external vessel , the air must in the like manner break forth , and shave the superficies of the inner vessel , and work through the water till it be frozen . a. i could easily assent to this , if i could conceive how the air that shaves ( as you say ) the outside of the vessel , could work through it . i conceive well enough a pail of water with ice or snow dissolving in it , and how it causeth wind. but how that wind should communicate it self through the vessel of wood or metal , so as to make it shave the superficies of the water which is within it , i do not so well understand . b. i do not say the inner superficies of the vessel shaves the water within it . but 't is manifest that the wind made in the pail of water by the melting snow or ice presseth the sides of the vessel that standeth in it ; and that the pressure worketh clean through , how hard soever the vessel be ; and that again worketh on the water within , by restitution of its parts , and so hardeneth the water by degrees . a. i understand you now . the ice in the pail by its dissolution transfers its hardness to the water within . b. you are merry . but supposing , as i do , that the ice in the pail is more than the water in the vessel , you will finde no absurdity in the argument . besides , the experiment , you know , is common . a. i confess it is probable . the greeks have the word 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 ( whence the latins have their word frigus ) to signifie the curling of water by the wind ; and use the same also for horrour , which is the passion of one that cometh suddenly into a cold air , or is put into a sudden affright , whereby he shrinks , and his hair stands upright . which manifestly shews that the motion which causeth cold , is that which pressing the superficies of a body , sets the parts of it closer together . but to proceed in my quaeries . monsieur des cartes , who ( you know ) hath written somewhere , that the noise we hear in thunder , proceeds from breaking of the ice in the clouds ; what think you of it ? can a cloud be turned into ice ? b. why not ? a cloud is but water in the air. a. but how ? for he has not told us that . b. you know that 't is onely in summer , and in hot weather , that it thunders ; or if in winter , it is taken for a prodigie . you know also , that of clouds , some are higher , some lower , and many in number , as you cannot but have oftentimes observed , with spaces between them . therefore , as in all currents of water , the water is there swiftest where it is streightned with islands , so must the current of air made by the annual motion be swiftest there , where it is checkt with many clouds through which it must ( as it were ) be strained , and leave behinde it many small particles of earth , always in it , and in hot weather more than ordinary . a. this i understand , and that it may cause ice . but when the ice is made , how is it broken ? and why falls it not down in shivers ? b. the particles are inclosed in small caverns of the ice ; and their natural motion being the same which we have ascribed to the globe of the earth , requires a sufficient space to move in . but when it is imprisoned in a less room that that , then a great part of the ice breaks : and this is the thunder-clap . the murmur following is from the settling of the air. the lightening is the fancie made by the recoiling of the air against the eye . the fall is in rain , not in shivers ; because the prisons which they break are extreme narrow , and the shivers being small , are dissolved by the heat . but in less heat they would fall in drops of hail , that is to say , half frozen by the shaving of the air as they fall , and be in a very little time ( much less than snow or ice ) dissolved . a. will not that lightning burn ? b. no. but it hath often kill'd men with cold. but this extraordinary swiftness of lightning consisteth not in the expansion of the air , but in a straight and direct stream from where it breaks forth ; which is in many places successively , according to the motion of the cloud . a. experience tells us that . i have now done with my problems concerning the great bodies of the world , the stars , and element of air in which they are moved , and am therein satisfied , and the rather , because you have answered me by the supposition of one onely motion , and commonly known , and the same with that of copernicus , whose opinion is received by all the learned ; and because you have not used any of these empty terms , sympathy , antipathy , antiperistasis , &c. for a natural cause , as the old philosophers have done to save their credit . for though they were many of them wise men , as plato , aristotle , seneca , and others , and have written excellently of morals and politiques , yet there is very little natural philosophy to be gathered out of their writings . b. their ethiques and politiques are pleasant reading , but i finde not any argument in their discourses of justice or vertue drawn from the supreme authority , on whose laws all justice , vertue , and good politiques depend . a. concerning this cover , or ( as some have called it ) the scurf or scab of the terrestrial star , i will begin with you to morrow . for it is a large subject , containing animals , vegetables , metals , stones , and many other kinds of bodies , the knowledge whereof is desired by most men , and of the greatest and most general profit . b. and this is it , in which i shall give you the least satisfaction ; so great is the variety of motion , and so concealed from humane senses . cap. vii . of hard and soft , and of the atomes that flie in the air. a. concerning this cover of the earth , made up of an infinite number of parts of different natures , i had much ado to finde any tolerable method of enquiry . but i resolved at last to begin with the questions concerning hard and soft , and what kinde of motion it is that makes them so . i know that in any pulsion of air , the parts of it go innumerable and inexplicable ways ; but i ask only if every point of it be moved . b. no. if you mean a mathematical point , you know it is impossible . for nothing is movable but body . but i suppose it divisible ( as all other bodies ) into parts divisible . for no substance can be divided into nothings . a. why may not that substance within our bodies , which are called animal spirits , be another kind of body , and more subtile than the common air ? b. i know not why , no more than you or any man else knows why it is not very air , though purer perhaps than the common air , as being strained through the blood into the brain and nerves . but howsoever that be , there is no doubt , but the least parts of the common air , ( respectively to the whole ) will easilier pierce ( with equal motion ) the body that resisteth them , than the least parts of water . for it is by motion onely that any mutation is made in any thing ; and all things standing as they did , will appear as they did . and that which changeth soft into hard , must be such as makes the parts not easily to be moved without being moved all together ; which cannot be done but by some motion compounded . and we call hard , that whereof no part can be put out of order without disordering all the rest ; which is not easily done . a. how water and air beaten into extreme small bubbles is hardned into ice , you have told me already , and i understand it . but how a soft homogeneous body , as air , or water , should be so hardned , i cannot imagine . b. there is no hard body that hath not also some degree of gravity ; and consequently , being loose , there must be some efficient cause , that is , some motion , when it is severed from the earth , to bring the same to it again . and seeing this compounded motion gives to the air and water an endeavour from the earth , the motion which must hinder it , must be in a way contrary to the compounded motion of the earth . for whatsoever , having been asunder , comes together again , must come contrary ways , as those that follow one another go the same way , though both move upon the same line . a. what experiment have you seen to this purpose ? b. i have seen a drop of glass like that of the second figure , newly taken out of the furnace , and hanging at the end of an iron rod , and yet fluid , and let fall into the water and hardned . the club-end of it a a coming first to the water , the tail b c following it . 't is proved before , that the motion that makes it is a compounded motion , and gives an endeavour outward to every part of it ; and that the motion which maketh cold , is such as shaving the body in every point of contact , and turning it , gives them all an endeavour inward . such is this motion made by the sinking of the hot and fluid glass into the water . 't is therefore manifest that the motion which hardneth a soft body , must in every point of contact be in the contrary way to that which makes a hard body soft . and further , that slender tail b c shall be made much more hard than common glass . for towards the upper end , in c , you cannot easily break it , as small as it is . and when you have broken it , the whole body will fall into dust , as it must do , seeing the bending is so difficult . for all the parts are bent with such force , that upon the breaking at d , by their sudden restitution to their liberty , they will break together . and the cause why the tail b c , being so slender , becomes so hard , is , that all the endeavour in the great part a b , is propagated to the small part b c , in the same manner as the force of the sun-beams is derived almost to a point by a burning-glass . but the cause why , when it is broken in d , it breaks also in so many other places , is , that the endeavour in all the other parts ( which is called the spring ) unbends it ; from whence a motion is caused the contrary way , and that motion continued bends it more the other way and breaks it , as a bow over-bent is broken into shivers by a sudden breaking of the string . a. i conceive now how a body which having been hard and softned again , may be re-hardned ; but how a fluid and meer homogeneous body , as air or water , may be so , i see not yet . for the hardning of water is making a hard body of two fluids , whereof one ( which is the water ) hath some tenacity ; and so a man may make a bladder hard with blowing into it . b. as for meer air , which hath no natural motion of it self , but is moved onely by other bodies of a greater consistence , i think it impossible to be hardned . for the parts of it so easily change places , that they can never be fixt by any motion . no more i think can water , which though somewhat less fluid , is with an insensible force very easily broken . a. it is the opinion of many learned men , that ice ( in long time ) will be turned into christal ; and they alleadge experience for it . for they say that christal is found hanging on high rocks in the alps like isicles on the eaves of a house , and why may not that have formerly been ice , and in many years have lost the power of being reduced ? b. if that were so , it would still be ice , though also christal : which cannot be , because christal is heavier than water , and therefore much heavier than ice . a. is there then no transubstantiation of bodies but by mixture ? b. mixture is no transubstantiation . a. have you never seen a stone that seemed to have been formerly wood , and some like shells , and some like serpents , and others like other things ? b. yes . i have seen such things , and particularly i saw at rome in a stone-cutters work-house a billet of wood , as i thought it , partly covered with bark , and partly with the grain bare , as long as a mans arm , and as thick as the calf of a mans leg ; which handling i found extreme heavie , and saw a small part of it which was polished , and had a very fine gloss , and thought it a substance between stone and metal , but neerest to stone . i have seen also a kind of slate painted naturally with forest-work . and i have seen in the hands of a chymist of my acquaintance at paris , a broken glass , part of a retort , in which had been the rozin of turpentine , wherein though there were left no rozin , yet there appeared in the piece of glass many trees ; and plants in the ground about them , such as grow in woods ; and better designed than they could be done by any painter ; and continued so for a long time . these be great wonders of nature , but i will not undertake to shew their causes . but yet this is most certain , that nothing can make a hard body of a soft , but by some motion of its parts . for the parts of the hardest body in the world can be no closer together than to touch ; and so close are the parts of air and water , and consequently they should be equally hard , if their smallest parts had not different natural motions . therefore if you ask me the causes of these effects , i answer , they are different motions . but if you expect from me how and by what motions , i shall fail you . for there is no kind of substance in the world now , that was not at the first creation , when the creator gave to all things what natural and special motion he thought good . and as he made some bodies wondrous great , so he made others wondrous little . for all his works are wondrous . man can but guess , nor guess further , than he hath knowledge of the variety of motion . i am therefore of opinion , that whatsoever perfectly homogeneous is hard , consisteth of the smallest parts ( or , as some call them , atomes ) that were made hard in the beginning , and consequently by an eternal cause ; and that the hardness of the whole body is caused onely by the contact of the parts by pressure . a. what motion is it that maketh a hard body to melt ? b. the same compounded motion that heats , namely , that of fire , if it be strong enough . for all motion compounded is an endeavour to dissipate ( as i have said before ) the parts of the body to be moved by it . if therefore hardness consist onely in the pressing contact of the least parts , this motion will make the same parts slide off from one another , and the whole to take such a figure as the weight of the parts shall dispose them to , as in lead , iron , gold , and other things melted with heat . but if the small parts have such figures as they cannot exactly touch , but must leave spaces between them filled with air or other fluids , then this motion of the fire , will dissipate those parts some one way , some another , the hard part still hard ; as in the burning of wood or stone into ashes or lime . for this motion is that which maketh fermentation , scattering dissimilar parts , and congregating similar . a. why do some hard bodies resist breaking more one way than another ? b. the bodies that do so , are for the most part wood , and receive that quality from their generation . for the heat of the sun in the spring-time draweth up the moisture at the root , and together with it the small parts of the earth , and twisteth it into a small twig by its motion upwards to some length , but to very little other dimensions , and so leaves it to dry till the spring following ; and then does the same to that , and to every small part round about it ; so that upward the strength is doubled , and the next year trebled , &c. and these are called the grain of the wood , and but touch one another , like sticks with little or no binding , and therefore can hardly be broken across the grain , but easily all-along it . also some other hard bodies have this quality of being more fragile one way than another , as we see in quarrels of a glass-window , that are aptest many times to break in some crooked line . the cause of this may be , that when the glass , hot from the furnace , is poured out upon a plain , any small stones in or under it will break the stream of it into divers lines , and not onely weaken it , but also cause it falsly to represent the object you look on through it . a. what is the cause why a bow of wood or steel , or other very hard body , being bent , but not broken , will recover its former degree of straightness ? b. i have told you already , how the smallest parts of a hard body have every one ( by the generation of hardness ) a circular , or other compounded motion ; such motion is that of the smallest parts of the bow. which circles in the bending you press into narrower figures , as a circle into an ellipsis , and an ellipsis into a narrower but longer ellipsis with violence ; which turns their natural motion against the outward parts of the bow so bent , and is an endeavour to stretch the bow into its former posture . therefore if the impediment be removed , the bow must needs recover its former figure . a. 't is manifest ; and the cause can be no other but that , except the bow have sense . b. and though the bow had sense , and appetite to boot , the cause will be still the same . a. do you think air and water to be pure and homogeneous bodies ? b. yes , and many bodies both hard and heavie to be so too , and many liquors also besides water . a. why then do men say they finde one air healthy , another infectious ? b. not because the nature of the air varies , but because there are in the air drawn , or rather , beaten up by the sun , many little bodies , whereof some have such motion as is healthful , others such as is hurtful to the life of man. for the sun ( as you see in the generation of plants ) can fetch up earth as well as water ; and from the driest ground any kind of body that lieth loose , so it be small enough , rather than admit any emptiness . by some of these small bodies it is that we live ; which being taken in with our breath , pass into our blood , and cause it ( by their compounded motion ) to circulate through the veins and arteries ; which the blood of it self ( being a heavie body ) without it cannot do . what kind of substance these atomes are , i cannot tell . some suppose them to be nitre . as for those infectious creatures in the air , whereof so many die of the plague , i have heard that monsieur des cartes , a very ingenious man , was of opinion , that they were little flies . but what grounds he had for it , i know not , though there be many experiments that invite me to believe it . for first , we know that the air is never universally infected over a whole country , but onely in or neer to some populous town . and therefore the cause must also be partly ascribed to the multitude thronged together , and constrained to carry their excrements into the fields round about and neer to their habitation . which in time fermenting breed worms , which commonly in a month or little more , naturally become flies ; and though engendred at one town , may flie to another . secondly , in the beginning of a plague , those that dwell in the suburbs , that is to say , neerest to this corruption , are the poorest of the people , that are nourished for the most part with the roots and herbs which grow in that corrupted dirt ; so that the same filth makes both the blood of poor people , and the substance of the fly. and 't is said by aristotle , that every thing is nourished by the matter whereof it is generated . thirdly , when a town is infected , the gentlemen , and those that live on wholsomest food , scarce one of five hundred die of the plague . it seems therefore , whatsoever creatures they be that invade us from the air , they can discern their proper nourishment , and do not enter into the mouth and nostrils with the breath of every man alike , as they would do if they were inanimate . fourthly , a man may carry the infection with him a great way into the country in his clothes , and infect a village . shall another man there draw the infection from the clothes onely by his breath ? or from the hangings of a chamber wherein a man hath died ? it is impossible . therefore whatsoever killing thing is in the clothes or hangings , it must rise and go into his mouth or nostrils before it can do him hurt . it must therefore be a fly , whereof great numbers get into the blood , and there feeding and breeding worms , obstruct the circulation of the blood , and kill the man. a. i would we knew the palate of those little animals ; we might perhaps finde some medicine to fright them from mingling with our breath . but what is that which kills men that lie asleep too neer a charcole-fire ? is it another kind of fly ? or is charcole venimous ? b. it is neither fly nor venim , but the effect of a flameless glowing fire , which dissipates those atomes that maintain the circulation of the blood ; so that for want of it , by degrees they faint , and being asleep cannot remove , but in short time , there sleeping die , as is evident by this , that being brought into the open air ( without other help ) they recover . a. 't is very likely . the next thing i would be informed of , is the nature of gravity . but for that , if you please , we will take another day . cap. viii . of gravity and gravitation . b. what books are those ? a. two books written by two learned men concerning gravity . i brought them with me , because they furnish me with some material questions about that doctrine ; though of the nature of gravity , i finde no more in either of them than this , that gravity is an intrinsecal quality by which a body so qualified descendeth perpendicularly towards the superficies of the earth . b. did neither of them consider that descending is local motion , that they might have called it an intrinsecal motion rather than an intrinsecal quality ? a. yes . but not how motion should be intrinsecal to the special individual body moved . for how should they , when you are the first that ever sought the differences of qualities in local motion , except your authority in philosophy were greater with them than it is ? for 't is hard for a man to conceive ( except he see it ) how there should be motion within a body , otherwise than as it is in living creatures . b. but it may be they never sought , or despaired of finding what natural motion could make any inanimate thing tend one way rather than another . a. so it seems . but the first of them enquires no further than , why so much water ( being a heavie body ) as lies perpendicularly on a fishes back in the bottom of the sea , should not kill it . the other ( whereof the author is dr. wallis ) treateth universally of gravity . b. well . but what are the questions which from these books you intend to ask me ? a. the author of the first book tells me , that water and other fluids are bodies continued , and act ( as to gravity ) as a piece of ice would do of the same figure and quantity . is that true ? b. that the universe ( supposing there is no place empty ) is one entire body , and also , as he saith it is , a continual body , is very true . and yet the parts thereof may be contiguous , without any other cohesion but touch. and it is also true , that a vessel of water will descend in a medium less heavie ( but fluid ) as ice would do . a. but he means that water in a tub would have the same effect upon a fish in the bottom of the tub , as so much ice would have . b. that also would be true , if the water were frozen to the sides of it . otherwise the ice ( if there be enough ) will crush the fish to death . but how applies he this , to prove that the water cannot hurt a fish in the sea by its weight ? a. it plainly appears that water does not gravitate on any part of it self beneath it . b. it appears by experience , but not by this argument , though instead of water the tub were fill'd with quicksilver . a. i thought so . but how it comes to pass that the fish remains uncrush'd , i cannot tell . b. the endeavour of the quicksilver downward , is stopt by the resistance of the hard bottom . but all resistance is a contrary endeavour ; that is , an endeavour upwards , which gives the like endeavour to the quicksilver , which is also heavie , and thereby the endeavour of the quicksilver is diverted to the sides round-about ; where stopt again by the resistance of the sides , it receives an endeavour upwards , which carries the fish to the top , lying all the way upon a soft bed of quicksilver . this is the true manner how the fish is saved harmless . but your author , i believe , either wanted age , or had too much business , to study the doctrine of motion ; and never considered that resistance is not an impediment onely , or privation , but a contrary motion ; and that when a man claps two pieces of wax together , their contrary endeavour will turn both the pieces into one cake of wax . a. i know not the author ; but it seems he has deeplier considered this question than other men . for in the introduction to his book , he saith , that men have pre-engaged themselves to maintain certain principles of their own invention , and are therefore unwilling to receive any thing that may render their labour fruitless : and that they have not strictly enough considered the several interventions that abate , impede , advance , or direct the gravitation of bodies . b. this is true enough ; and he himself is one of those men , in that he considered not , that resistance is one of those interventions , which abate , impede , and direct gravitation . but what are his suppositions for the question he handles ? a. his first is , that as in a pyramide of brick , wherein the bricks are so joyned , that the uppermost lies every where over the joynt or cement of the two next below it , you may break down a part , and leave a cavity , and yet the bricks above will stand firm and sustain one another by their cross posture : so also it is in wheat , hail-shot , sand , or water ; and so they arch themselves , and thereby the fish is every way secured by an arch of water over it . b. that the cause why fishes are not crusht nor hurt in the bottom of the sea by the weight of the water , is the waters arching it self , is very manifest . for if the uppermost orb of the water should descend by its gravity , it would tend toward the centre of the earth , and place it self all the way in a less and lesser orb ; which is impossible . for the places of the same body are always equal . but that wheat , sand , hail-shot , or loose stones should make a firm arch , is not credible . a. the author therefore ( it seems ) quits it : and taketh a second hypothesis for the true cause , though the former ( he saith ) be not useless , but contributes its part to it . b. i see , though he depart from his hypothesis , he looks back upon it with some kindness . what is his second hypothesis ? a. it is , that air and water have an endeavour to motion upward , downward , directly , obliquely , and every way . for air ( he saith ) will come down his chimney , and in at his door , and up his stairs . b. yes , and mine too ; and so would water if i dwelt under water , rather than admit of vacuum . but what of that ? a. why then it would follow , that those several tendencies or endeavours would so abate , impede , and correct one another , as none of them should gravitate . which being granted , the fish can take no harm . wherein i finde one difficulty . which is this : the water having an endeavour to motion every way at once , methinks it should go no way , but lie at rest ; which , he saith , was the opinion of stevinus , and rejecteth it , saying , it would crush the fish into pieces . b. i think the water in this case would neither rest nor crush . for the endeavour being ( as he saith ) intrinsecal , and every way , must needs drive the water perpetually outward , that is to say ( as to this question ) upwards ; and seeing the same endeavour in one individual body cannot be more ways at once than one , it will carry it on perpetually without limit , beyond the fixed stars ; and so we shall never more have rain . a. as ridiculous as it is , it necessarily follows . b. what are dr. wallis his suppositions ? a. he goes upon experiments . and first he alleadgeth this , that water left to it self without disturbance , does naturally settle it self into a horizontal plain . b. he does not then ( as your author and all other men ) take gravity for that quality whereby a body tendeth to the centre of the earth . a. yes , he defines gravity to be a natural propension towards the centre of the earth . b. then he contradicteth himself . for if all heavie bodies tend naturally to one centre , they shall never settle in a plain , but in a spherical superficies . but against this , that such an horizontal plain is found in water by experience , i say it is impossible . for the experiment cannot be made in a bason , but in half a mile at sea , experience visibly shews the contrary . according to this , he should think also that a pair of scales should hang parallel . a. he thinks that too . b. let us then leave this experiment . what saies he further concerning gravity ? a. he takes for granted ( not as an experiment , but an axiome ) that nature worketh not by election , but ad ultimum virium , with all the power it can . b. i think he means ( for 't is a very obscure passage ) that every inanimate body by nature worketh all it can without election ; which may be true . but 't is certain that men ( and beasts ) work often by election , and often without election ; as when he goes by election , and falls without it . in this sence i grant him , that nature does all it can . but what infers he from it ? a. that naturally every body has every way ( if the ways oppose not one another ) an endeavour to motion . and consequently , that if a vessel have two holes , one at the side , another at the bottom , the water will run out at both . b. does he think the body of water that runs out at the side , and that which runs out at the bottom is but one and the same body of water ? a. no sure . he cannot think but that they are two several parts of the whole water in the vessel . b. what wonder is it then , if two parts of water run two ways at once , or a thousand parts a thousand ways ? does it follow thence that one body can go more than one way at once ? why is he still medling with things of such difficulty ? he will finde at last that he has not a genius either for natural philosophy or for geometry . what other suppositions has he ? a. my first author had affirmed , that a lighter body does not gravitate on a heavier ; against this dr. wallis thus argueth : let there be a siphon a b c d filled with quicksilver to the level a d. if then you pour oyl upon a as high as to e , he asketh if the oyl in a e ( as being heavie ) shall not press down the quicksilver a little at a , and make it rise a little at d , suppose to f. and answers himself , that certainly it will. so that it is neither an experiment nor an hypothesis , but onely his opinion . b. whatsoever it be , it is not true ; though the doctor may be pardoned , because the contrary was never proved . a. can you prove the contrary ? b. yes . for the endeavour of the quicksilver both from a and d downward , is stronger than that of the oyl downward . if therefore the endeavour of the quicksilver were not resisted by the bottom b c , it would fall so , by reason of the acceleration of heavie bodies in their descending , as to leave the oyl , so that it should not onely not press , but also not touch the quicksilver . it is true in a pair of scales equally charged with quicksilver , that the addition of a little oyl to either scale , will make it praeponderate . and that was it deceiv'd him . a. 't is evident . the last experiment he cites is the weighing of air in a pair of scales , where 't is found manifestly that it has some little weight . for if you weigh a bladder , and put the weight into one scale , and then blow the bladder full of air , and put it into the other scale , the full bladder will outweigh the empty . must not then the air gravitate ? b. it does not follow . i have seen the experiment just as you describe it , but it can never be thence demonstrated that air has any weight . for as much air as is prest downward by the weight of the blown bladder , so much will rise from below , and lay it self spherically at the altitude of the center of gravity of the bladder so blown . so that all the air within the bladder above that centre , is carried thither imprisoned , and by violence : and the force that carries it up , is equal to that which presseth it down . there must therefore be allowed some little counterpoise in the other scale to ballance it . therefore the experiment proves nothing to his purpose . and whereas they say there be small heavie bodies in the air , which make it gravitate , do they think the force which brought them thither cannot hold them there ? a. i leave this question of the fish , as cleerly resolved , because the water tending every way to one point ( which is the centre of the earth ) must of necessity arch it self . and now tell me your own opinion concerning the cause of gravity , and why all bodies descend or ascend not all alike . for there can be no more matter in one place than another if the places be equal . b. i have already shewed you in general , that the difference of motion in the parts of several bodies makes the difference of their natures . and all the difference of motions consisteth either in swiftness , or in the way , or in the duration . but to tell you in special , why gold is heaviest , and then quicksilver , and then ( perhaps ) lead , is more than i hope to know , or mean to enquire : for i doubt not but that the species of heavie , hard , opaque , and diaphanous , were all made so at their creation , and at the same time separated from different species . so that i cannot guess at any particular motions that should constitute their natures , further than i am guided by the experiments made by fire or mixture . a. you hope not then to make gold by art ? b. no , unless i could make one and the same thing heavier than it was . god hath from the beginning made all the kindes of hard , and heavie , and diaphanous bodies that are , and of such figure and magnitude as he thought fit ; but how small soever , they may by accretion become greater in the mine , or perhaps by generation , though we know not how . but that gold , by the art of man should be made of not gold , i cannot understand ; nor can they that pretend to shew how . for the heaviest of all bodies , by what mixture soever of other bodies , will be made lighter ; and not to be received for gold. a. why , when the cause of gravity consisteth in motion , should you despair of finding it ? b. it is certain , that when any two bodies meet , as the earth and any heavie body will , the motion that brings them to or towards one another , must be upon two contrary ways ; and so also it is when two bodies press each other in order to make them hard. so that one contrariety of motion might cause both hard and heavie . but it doth not . for the hardest bodies are not always the heaviest . therefore i finde no access that way to compare the causes of different endeavours of heavie bodies to descend . a. but shew me at least how any heavie body that is once above in the air , can descend to the earth , when there is no visible movent to thrust or pull it down . b. 't is already granted , that the earth hath this compounded motion supposed by copernicus , and that thereby it casteth the contiguous air from it self every way round-about . which air so cast off , must continually by its nature , range it self in a spherical orb. suppose a stone ( for instance ) were taken up from the ground , and held up in the air by a mans hand , what shall come into the place it fill'd when it lay upon the earth ? a. so much air as is equal to the stone in magnitude , must descend and place it self in an orb upon the earth . but then i see that to avoid vacuum , another orb of air of the same magnitude must descend , and place it self in that , and so perpetually to the mans hand ; and then so much air as would fill the place must descend in the same manner , and bring the stone down with it . for the stone having no endeavour upward , the least motion of the air ( the hand being removed ) will thrust it downward . b. 't is just so . and further , the motion of the stone downward shall continually be accelerated according to the odde numbers from unity ; as you know hath been demonstrated by galileo . but we are nothing the nearer by this , to the knowledge of why one body should have a greater endeavour downward than another . you see the cause of gravity is this compounded motion with exclusion of vacuum . a. it may be 't is the figure that makes the difference . for though figure be not motion , yet it may facilitate motion , as you see commonly the breadth of a heavie body retardeth the sinking of it . and the cause of it is , that it makes the air have further to go laterally , before it can rise from under it . for suppose a body of quicksilver falling in the air from a certain height , must it not ( going as it does towards the centre of the earth ) as it draws neerer and neerer to the earth , become more and more slender , in the form of a solid sector ? and if it have far to go , divide it self into drops ? this figure of a solid sector is like a needle with the point downward , and therefore i should think that facilitating the motion of it does the same that would be done by increasing the endeavour . b. do not you see that this way of facilitating is the same in water , and in all other fluid heavy bodies . besides , your argument ought to be applicable to the weighing of bodies in a pair of scales ( which it is not , for there they have no such figure ) it should also hold in the comparison of gravity in hard and fluid bodies . a. i had not sufficiently consider'd it . but supposing now ( as you do ) that both heavy and hard bodies , in their smallest parts , were made so in the creation ; yet , because quicksilver is harder than water , a drop of water shall in descending be prest into a more slender sector than a drop of quicksilver , and consequently the earth shall more easily cast off any quantity of water than the same quantity of quicksilver . b. this one would think were true ; as also that of simple fluid bodies , those whose smallest parts , naturally , without the force of fire do strongliest cohere , are generally the heaviest . but why then should quicksilver be heavier than stone or steel ? fluidity and hardness are but degrees between greater fluidity and greater hardness . therefore to the knowledge of what it is that causeth the difference , in different bodies , of their endeavour downward , there are required ( if it can be known at all ) a great many more experiments than have been yet made . it is not difficult to find why water is heavier than ice , or other body mix'd of air and water . but to believe that all bodies are heavier or lighter according to the quantity of air within them , is very hard . a. i see by this , that the creator of the world , as by his power he ordered it , so by his wisdom he provided it should be never disordered . therefore leaving this question , i desire to know whether if a heavy body were as high as a fixt star , it would return to the earth . b. 't is hard to try . but if there be this compounded motion in the great bodies so high , such as is in the earth , it is very likely that some heavy bodies will be carried to them . but we shall never know it till we be at the like height . a. what think you is the reason why a drop of water ( though heavy ) will stand upon a horizontal plain of dry or unctuous wood , and not spread it self upon it ? for let a b ( in the th figure ) be the dry plain , d the drop of water , and d c perpendicular to a b. the drop d ( though higher ) will not descend and spread it self upon it . b. the reason i think is manifest . for those bodies which are made by beating of water and air together , shew plainly that the parts of water have a great degree of cohesion . for the skin of the bubble is water , and yet it can keep the air ( though moved ) from getting out . therefore the whole drop of water at d , hath a good deal of cohesion of parts . and seeing a b is an horizontal plain , the way from the contact in d either to a or b is upwards , and consequently there is no endeavour in d either of those ways , but what proceeds from so much weight of water as is able to break that cohesion , which so small a drop is too weak to do . but the cohesion being once broken , as with your finger , the water will follow . a. seeing the descent of a heavy body increaseth according to the odd numbers , , , , &c. and the aggregates of those numbers , viz. of and ; and and and ; and of and and and , &c. are square numbers , namely . . , the whole swiftness of the descent will be , i think , to the aggregate of so many swiftnesses equal to the first endeavour , as square numbers are to their sides , , , , . is it so ? b. yes , you know it hath been demonstrated by galileo . a. then if ( for instance ) you put into a pair of scales equal quantities of quicksilver and water , seeing they are both accelerated in the same proportion , why should not the weight of quicksilver to the weight of water be in duplicate proportions to their first endeavours ? b. because they are in a pair scales . for there the motion of neither of them is accelerated . and therefore it will be , as the first endeavour of the quicksilver to the first endeavour of the water , so the whole weight to the whole weight . by which you may see , that the cause which takes away the gravitation of liquid bodies from fish or other lighter bodies within them , can never be derived from the weight . a. i have one question more to ask concerning gravity . if gravity be ( as some define it ) an intrinsecal quality , whereby a body descendeth towards the center of the earth , how is it possible that a piece of iron that hath this intrinsecal quality , should rise from the earth , to go to a loadstone ? hath it also an intrinsecal quality to go from the earth ? it cannot be . the cause therefore must be extrinsecal . and because when they are come together in the air , if you leave them to their own nature , they will fall down together , they must also have some like extrinsecal cause . and so this magnetique vertue will be such another vertue as makes all other heavy bodies to descend ( in this our world ) to the earth . if therefore you can from this your hypothesis of compounded motion , by which you have so probably salved the problem of gravity , salve also this of the loadstone , i shall acknowledge both your hypothesis to be true , and your conclusion to be well deduced . b. i think it not impossible . but i will proceed no further in it now , than ( for the facilitating of the demonstrations ) to tell you the several proprieties of the magnet , whereof i am to shew the causes . as first , that iron , and no other body , at some little distance ( though heavy ) will rise to it . secondly , that if it be laid upon a still water in a floating vessel , and left to it self , it will turn it self till it lye in a meridian , that is to say , with one and the same line still north and south . thirdly , if you take a long slender piece of iron , and apply the loadstone to it , and ( according to the position of the poles of the loadstone ) draw it over to the end of the iron , the iron will have the same poles with the magnet , so it be drawn with some pressure ; but the poles will lye in a contrary position ; and also this long iron will draw other iron to it as the magnet doth . fourthly , this long iron , if it be so small as that poiz'd upon a pin , the weight of it have no visible effect , the navigators use it for the needle of their compass , because it points north and south ; saving that in most places by particular accidents it is diverted ; which diversion is called the variation of the horizontal needle . fifthly , the same needle placed in a plain perpendicular to the horizon , hath another motion called the inclination . which that you may the better conceive , draw a fourth figure ; wherein let there be a circle to represent the terrella , that is to say , a spherical magnet . a. let this be it , whose center is a , the north pole b , the south pole c. b. join b c , and cross it at right angles with the diameter d e. a. 't is done . b. upon the point d set the needle parallel to b c , with the cross for the south pole , and the barb for the north ; and describe a square about the circle b d c e , and divide the arch d b into four equal parts in a , b , c. a. 't is done . b. then place the middle of the needle on the points a , b , c , so that they may freely turn ; and set the barb which is at d toward the north , and that which is at c towards the south . you see plainly by this , that the angles of inclination through the arch d c taken all together , are double to a right angle . for when the south point of the needle , looking north , as at d , comes to look south , as at c , it must make half a circle . a. that is true . and if you draw the sine of the arch d a ( which is d a ) and the sine of the arch b a ( which is a c ) and the sine of the arch d b ( which is b f ) and the sine of the arch b c ( which is c g ) the needle will lye upon b f with the north-point downwards , so that the needle will be parallel to a d. then from a draw the line a h , making the angle e a h equal to the angle d a a. and then the needle at a shall lye in the line a h with the south point toward h. finally , draw the line c h , which ( with c g ) will also make a quarter of a right angle ; and therefore if the needle be plac'd on the point c it will lye in c h with the south point toward h. and thus you see by what degrees the needle inclines or dips under the horizon more and more from d till it come to the north pole at b ; where it will lye parallel to the needle in d ; but with their barbs looking contrary ways . and this is certain by experience , and by none contradicted . b. you see then why the degrees of the inclinatory needle in coming from d to b are double to the degrees of a quadrant . it is found also by experience , that iron both of the mine and of the furnace put into a vessel so as to float , will lay it self ( if some accident in the earth hinder it not ) exactly north and south . and now i am , from this compounded motion supposed by copernicus , to derive the causes why a loadstone draws iron ; why it makes iron to do the same ; why naturally it placeth it self in a parallel to the axis of the earth ; why by passing it over the needle it changes its poles ; and what is the cause that it inclines . but it is your part to remember what i told you of motion at our second meeting ; and what i told you of this compounded motion supposed by copernicus , at our fourth meeting . cap. ix . of the loadstone , and its poles ; and whether they shew the longitude of places on the earth . a. i come now to hear what natural causes you can assign of the vertues of the magnet ; and first , why it draws iron to it , and only iron . b. you know i have no other cause to assign but some local motion , and that i never approved of any argument drawn from sympathy , influence , substantial forms , or incorporeal effluvia . for i am not , nor am accounted by my antagonists for a witch . but to answer this question , i should describe the globe of the earth greater than it is at b in the first figure , but that the terrella in the fourth figure will serve our turn . for 't is but calling b and c the poles of the earth , and d e the diameter of the aequinoctial circle , and making d the east , and e the west . and then you must remember that the annual motion of the earth is from west to east , and compounded of a straight and circular motion , so as that every point of it shall describe a small circle from west to east , as is done by the whole globe . and let the circles about a b c be three of those small circles . a. before you go any further , i pray you shew me how i must distinguish east and west in every part of this figure . for wheresoever i am on earth ( suppose at london ) and see the sun rise ( suppose in cancer ) is not a straight line from my eye to the sun terminated in the east ? b. 't is not due east , but partly east , partly south . for the earth ( being but a point compared to the sun ) all the parallels to d e the aequator , such as are e a , f b , e g , if they be produced , will fall upon the body of the sun. and therefore a b is north-east ; a a east north-east ; and a c north north-east . a. proceed now to the cause of attraction . b. suppose now that the internal parts of the loadstone had the same motion with that of the internal parts of the sun which make the annual motion of the earth from west to east , but in a contrary way , for otherwise the loadstone and the iron can never be made to meet . then set the loadstone at a little distance from the earth , marked with z ; and the iron marked with x upon the superficies of the earth . now that which makes x rise to z , can be nothing else but air ; for nothing touches it but air. and that which makes the air to rise , can be nothing but those small circles made by the parts of the earth ( such as are at a b c , ) for nothing else touches the air. seeing then the motion of each point of the loadstone is from east to west in circles , and the motion of each point of the iron from west to east ; it follows , that the air between the loadstone and the iron shall be cast off both east and west ; and consequently the place left empty , if the iron did not rise up and fill it . thus you see the cause that maketh the loadstone and the iron to meet . a. hitherto i assent . but why they should meet when some heterogeneous body lyes in the air between them , i cannot imagine . and yet i have seen a knife , though within the sheath , attract one end of the needle of a mariners compass ; and have heard it will do the same though a stone-wall were between . b. such iron were indeed a very and vigorous loadstone . but the cause of it is the same that causeth fire or hot water ( which have the same compounded motion ) to work through a vessel of brass . for though the motion be altered by restraint within the heterogeneous body , yet being continued quite through it restores it self . a. what is the cause why the iron rub'd over by a loadstone will receive the vertue which the loadstone hath of drawing iron to it ? b. since the motion that brings two bodies to meet must have contrary ways , and that the motions of the internal parts of the magnet and of the iron are contrary ; the rubbing of them together does not give the iron the first edeavour to rise , but multiplies it . for the iron untouch'd will rise to a loadstone ; but if touch'd , it becomes a loadstone to other iron . for when they touch a piece of iron they pass the loadstone over it only one way , viz. from pole to pole ; not back again , for that would undo what before had been done ; also they press it in passing , to the very end of the iron , and somewhat hard . so that by this pressing motion all the small circles about the points a b c , are turned the contrary way . and the halves of those small circles made on the arch d b will be taken away , and the poles changed , so as that the north-poles shall point south , and the south poles north , as in the figure . a. but how comes it to pass , that when a loadstone hath drawn a piece of iron , you may add to it another , as if they begat one another ? is there the like motion in the generation of animals ? b. i have told you that iron of it self will rise to the loadstone . much more then will it adhere to it when it is armed with iron , and both it and the iron have a plain superficies . for then not only the points of contact will be many ( which make the coherence stronger ) but also the iron wherewith it is armed is now another loadstone , differing a little ( which you perhaps think ) as male and female . but whether this compounded motion and confrication causeth the generation of animals , how should i know , that never had so much leasure as to make any observation which might conduce to that ? a. my next question is , seeing you say the loadstone , or a needle touch'd with it , naturally respecteth the poles of the earth , but that the variation of it proceedeth from some accidents in the superficies of the earth ; what are those accidents ? b. suppose there be a hill upon the earth ( for example ) at r ; then the stream of the air which was between z and x westward , coming to the hill , shall go up the hills side , and so down to the other side , according to the crooked line which i have mark'd about the hill by points ; and this infallibly will turn the north-point of the needle , being on the east side , more toward the east , and that on the other side more towards the west , than if there had been no hill. and where upon the earth are there not eminencies and depressions , except in some wide sea , and a great way from land ? a. but if that be true , the variation in the same place should be always the same . for the hills are not removed . b. the variation of the needle at the same place is still the same : but the variation of the variation is partly from the motion of the pole it self , which by the astronomers is called motus trepidationis ; and partly from that , that the variation cannot be truly observ'd : for the horizontal needle and the inclinatory needle incline alike , but cannot incline in due quantity . for whether set upon a pin or an axis , their inclination is hindred in the horizontal needle by the pin it self . if upon an axis , if the axis be just , it cannot move ; if slack , the weight will hinder it . but chiefly because the north pole of the earth draws away from it the north pole of the needle . for two like poles cannot come together . and this is the cause why the variation in one place is east , and another west . a. this is indeed the most probable reason why the variation varies , that ever i heard given . and i should presently acknowledge that this parallel motion of the axis of the earth in the ecliptick , supposed by copernicus , is the true annual motion of the earth , but that there is lately come forth a book called longitude found , which makes the magnetical poles distant from the poles of the earth eight degrees and a half . b. i have the book . 't is far from being demonstrated , as you shall find if you have the patience to see it examined . for wheresoever his demonstration is true , the conclusion ( if rightly inferred ) will be this , that the poles of the loadstone and the poles of the earth are the same . and where on the contrary his demonstrations are fallacies , it is because sometimes he fancieth the lines he hath drawn , not where they are ; sometimes because he mistakes his station ; and sometimes because he goes on some false principle of natural philosophy ; and sometimes also because he knoweth not sufficiently the doctrine of spherical triangles . a. i think that 's the book there which lyes at your elbow . pray you read . b. i find first ( pag. . ) that the ground of his argument are the two observations made by mr. burroughs ; one at vaygates , in , where the variation from the pole of the earth he found to be deg . min. east ; the other at lime-house near london , in , where the variation from the pole of the earth was deg . min. west . by which he saith , he might find out the magnetical pole. a. where is vaygate ? b. in degrees of north latitude , the difference of longitude between london and it being degrees . a. the longitude of places being yet to seek , how came he to know this difference of degrees , except the poles of the magnet and the earth be the same ? b. i believe he trusted to the globe for that . for the distance between the places is not above miles the nearest way . but we will pass by that , and come to his demonstration , and to his diagram , wherein l is london , p the north-pole of the earth , v vaygates . so that l p is deg . min. p v deg . the angle l p v deg . for the difference between the longitudes of vaygates and london . this is the construction . but before i come to the demonstration , i have an inference to draw from these observations , which is this . because in the same year the variation at london was deg . min. east , and at vaygates deg . min. west ; if you substract deg . min. from the arc l p ; and deg . min. from the arc l v , the variation on both sides will be taken away ; so that p v being the meridian of vaygates , and l p the meridian of london , they shall both of them meet in p the pole of the earth . and if the pole of the magnet be nearer to the zenith of london than is the pole of the earth , it shall be just as much nearer to the zenith of vaygates in the meridian of vaygates which is p v ; as is manifest by the diurnal motion of the earth . a. all this i conceive without difficulty . proceed to the demonstration . b. mark well now . his words are these , ( pag. . ) from p l v substract deg . min. and there remains the angle v l m. consider now which is the angle p l v , and which is the remaining angle v l m , and tell what you understand by it . a. he has mark'd the angle p l v with two numbers , deg . min. and deg . min. which together make deg . min. and the angle deg . min. being substracted from p l v , there will remain deg . min. for the angle v l m. i know not what to say to it . for i thought the arc p v , which is deg . had been the arc of the spherical angle p l v ; and that the arc l v had been deg . because he says the angle l p v is so ; and that the arc l m had been deg . because the angle l p m is so ; and lastly , that the angle p l m had been deg . min. because the arc p m is so . b. and what you thought had been true , if a spherical angle were a very angle . for all men that have written of spherical triangles take for the ground of their calculation ( as regiomontanus , copernicus , and clavius , ) that the arch of a spherical angle is the side opposite to the angle . you should have considered also that he makes the angle v p m deg . but sets down no arc to answer it . but that you may find i am in the right , look into the definitions which clavius hath put down before his treatise of spherical triangles , and amongst them is this ; the arc of a spherical triangle is a part of a great circle intercepted between the two sides drawn from the pole of the said great circle . a. the book is nothing worth ; for it is impossible to substract an arc of a circle out of a spherical angle . and i see besides that he takes the superficies that lyeth between the sides l p and l m for an arch , which is the quantity of an angle ; and is a line , and cannot be taken out of a superficies . i wonder how any man that pretends to mathematicks could be so much mistaken . b. 't is no great wonder . for clavius himself striving to maintain that a right angle is greater than the angle made by the diameter and the circumference , fell into the same errour . a corner ( in vulgar speech , ) and an angle ( in the language of geometry ) are not the same thing . but it is easie even for a learned man sometimes to take them for the same , as this author now has done ; and proceeding he saith , substract deg . min. from the angle p v l , and there remains the angle l v m. a. that again is false , because impossible . what was it that deceiv'd him now ? b. the same misunderstanding of the nature of a spherical angle . which appears further in this , that when he knew the arc v p was part of a great circle , he thought v m ( which he maketh deg . min. ) were also parts of a great circle ; which is manifestly false . for two great circles ( because they pass through the center ) do cut each other into halves . but p v is not half a circle . he sure thought himself at vaygates , and that p m v was equal to p v , although in the same hemisphere . a. but how proves he that the arc pm is deg . min ? b. thus. we have in two triangles , p l m and p v m , two sides and one angle included , to find p m the distance of the magnetical pole from the pole of the earth deg . min. a. is that all ? 't is very short for a demonstration of two so difficult problems , as the quantity of deg . min. and of the place of the magnetical pole. but he has proved nothing till he has shew'd how he found it . and though p m be deg . min. it follows not that m is the magnetical pole. b. nor is it true . for if p m be deg . min. and v m deg . min. the whole arc p m v will be deg . min. which should be deg . besides , whereas the variations were east and west , the substracting of them should be also east and west , but they are north and south . a. i am satisfied that the magnetical poles and the poles of the earth are the same . but thus much i confess , that if they were not the same , the longitude were found . for the difference of the latitudes of the earths aequator and of the magnetical aequator is the difference of the longitude . but proceed . b. the earth being a solid body , and the magnetick sphere that encompasseth the earth being a substance that hath not solidity to keep pace with the earth , looseth in its motion . and that may be the cause of the motion of the magnetick poles from east to west . a. this is very fine , and unexpected . the magnetick sphere ( which i took for a globe made of a magnet ) has not solidity to keep pace with the earth , though it be one of the hardest stones that are . it encompasseth the earth ; yet i thought nothing had encompassed the earth but air in which i breath and move . by this also the whole earth must be a loadstone . for two bodies cannot be in one place . so that he is yet no further than dr. gilbert whom he sleights . and if the sphere be a magnet , then the earth and loadstone have the same poles . see the force of truth ! which though it could not draw to it his reason , hath drawn his words to it . b. but perhaps he meant that the magnetick vertue encompasseth the earth , and not the magnetick body . a. but that helpeth him not . for if the body of the magnet be not there , the vertue then is the vertue of the earth ; and so again the poles of the earth are magnetick poles . b. you see how unsafe it is to boast of doctrines as of gods gifts , till we are sure that they are true . for god giveth and denieth as he pleaseth , not as our selves wish ; as now to him he hath given confidence enough , but hath denied him ( at least hitherto ) the finding of the longitudes . in the next place ( pag. . ) he seems much pleased that his doctrine agrees with an opinion of keplerus , that from the creation to the year of our lord it is to the year now years ; and with that which he saith some divines have held in times past , that as this world was created in six days , so it should continue six thousand years . by which account the world will be at an end years hence ; though the scripture tell us it shall come as a thief in the night . o what advantage years hence will they have that know this , over them that know it not , by taking up money at interest , or selling lands at years purchase ! a. but he says he will not meddle with that . b. yes , when he had medled with it too much already . a. but you have not told me wherein consisteth this agreement between him and keplerus . b. i forgot it . 't is in the motion of the magnetick poles . for precedently ( pag. . ) he had said that their period or revolution was years ; their yearly motion min. and ( pag. . ) that their motion is by sixes . six tenths of a degree in one year ; six degrees in ten year ; sixty degrees in a hundred year ; and six times sixty degrees in year . a. but what natural cause doth he assign of this revolution of years ? b. none at all . for the magnet lying upon the earth , can have no motion at all but what the earth and the air give it . and because it is always at deg . min. distance from the pole of the earth , the earth can give it no other motion than what it gives to its own poles by the precession of the aequinoctial points . nor can the air give it any motion but by its stream ; which must needs vary when the stream varieth . but what a vast difference does he make between the period of the motion of the aequinoctial points , which are about or near years according to copernicus ( lib. . cap. . ) which makes the annual precession to be seconds , and the period of the magnetical poles motion , which is but years . a. go on . b. he comes now ( pag. . ) to the inclinatory needle upon a spherical loadstone . where he shews , by diagram , that the needle and the instrument together moved toward the magnetical pole , make the sum of the inclinations equal to two quadrants , setting the north-point of the needle southward . which i confess is true . but ( in the same page ) he ascribeth the same motion to the earth in these words : as the horizontal needle hath a double motion about the round loadstone or terrulla , so also the inclinatory needle hath a double motion about the earth . what is this , but a confession that the poles of the magnet and of the earth are the same ? a. 't is plain enough . b. besides , seeing he placeth the magnetical pole at m in the meridian of vaygates , the needle being touch'd shall incline to the pole of the earth which is p , as well there as at london , and make the north-pole of the earth point south . a. 't is certain , because he puts both the magnetical pole and the pole of the earth in the same meridian of the earth . nor see i any cause why , the needle being the same , it should not be as subject to variation , and to variation of variation , and to all accidents of the earth there , as in any other part . b. he putteth ( pag. . ) a question , at what distance from the earth are the magnetick poles ? and answers to it , they are very near the earth , because the nearer the earth , the greater the strength . what think you of this ? a. i think they are in the superficies of the magnet , as the pole of the earth is in the superficies of the earth . and consequently , that then the earth must be a part of the magnet , and their poles the same . for the body of the magnet and the body of the earth , if they be two , cannot be in one place . b. his next words are , some things are to be considered concerning those variations of the horizontal needle which are not according to the scituation of the place from the magnetick poles , but are contrary ; as all the west-indies according to the poles should be easterly , and they are westerly . which is by some accidental cause in the earth ; and their motion , as i formerly said , is a forced motion , and not natural . a. he has clearly overthrown his main doctrine . for to say the motion of the needle is forced and unnatural , is a most pityful shift , and manifestly false , no motion being more constant or less accidental , notwithstanding the variation , to which the inclinatory needle is no less subject than the horizontal needle . b. that which deceived him , was , that he thought them two sorts of needles , forgetting what he had said of normans invention of the inclinatory needle by the inclining of the horizontal needle , pag. . for i will shew you that what he says is easterly and should be westerly , should be easterly as it is . consider the fourth figure , in which b is the north-pole , and b c deg . min. easterly , which was the variation at london in easterly . suppose a c to be the needle , shall it not incline , as well here as at d a , and the variation b c be easterly ? again , d a is deg . min. and the needle in d parallel to a b , and at a inclining also deg . min. westerly . and is not the variation there d a westerly , with the north-point of the needle in the line a h ? a. but the west-indies are not in this hemisphere b c d e. the variation therefore will proceed in an arc of the opposite hemisphere , which is westerly . b. i believe he might think so , forgetting that he and his compass were on the superficies of the earth , and fancying them in the center at a. a. 't is like enough . if we had a straight line exactly equal to the arc of a quadrant , i think it would very much facilitate the doctrine of spherical triangles . b. when you have done with your questions of natural philosophy , i will give you a clear demonstration of the equality of a straight line to the arc of a quadrant , which , if it satisfie you , you may carry with you , and try thereby if you can find the angle of a spherical triangle given . a. it is time now to give over . and at our next meeting i desire your opinion concerning the causes of diaphaniety , and refraction . this copernicus has done much more than he thought of . for he has not only restored to us astronomy , but also made the way open to physiology . cap. x. of transparence , refraction ; and of the power of the earth to produce living creatures . a. thinking upon what you said yesterday , it lookt like a generation of living creatures . i saw the love between the loadstone and the iron in their mutual attraction , their engendring in their close and contrary motion ; and their issue in the iron , which being touch'd hath the same attractive vertue . now seeing they have the same internal motion of parts with that of the earth , why should not their substance be the same , or very near a kin ? b. the most of them ( if not all ) that have written of this subject , when they call the loadstone a terrella , seem to think as you do . but i , except i could find proof for it , will not affirm it . for the earth attracteth all kind of bodies but air , and the loadstone none but iron . the earth is a star , and it were too bold to pronounce any sentence of its substance , especially of the planets , that are so lapt up in their several coats , as that they cannot work on our eyes , or any organ of our other senses . a. i come therefore now to the business of the day . seeing all generation , augmentation , and alteration is local motion , how can a body not transparent be made transparent ? b. i think it can never be done by the art of man. for as i said of hard and heavy bodies in the creation , so i think of diaphanous , that the very same individual body which was not transparent then , shall never be made transparent by humane art. a. do not you see that every day men make glass , and other diaphanous bodies not much inferior in beauty to the fairest gems ? b. it is one thing to make one transparent of many by mixture , and another to make transparent of not transparent . any very hard stone , if it be beaten into small sands , such as is used for hour-glasses , every one of those sands , if you look upon it with a microscope , you will find to be transparent ; and the harder and whiter the sone is , so much the more transparent , as i have seen in the stone of which are made milstones , which stone is here called greet . and i doubt not but the sands of white marble must be more transparent . but there are no sands so transparent that they have not a scurf upon them as hard , perhaps , as the stone it self ; which they whose profession it is to make glass , have the art to scour and wash away . and therefore i think it no great wonder to bring those sands into one lump , though i know not how they do it . a. i know they do it with lie made with a salt extracted from the ashes of an herb , of which salt they make a strong lie , and mingle it with the sand , and then bake it . b. like enough . but still it is a compound of two transparent bodies , whereof one is the natural stone , the other is the morter . this therefore doth not prove , that one and the same body , of not transparent can be made transparent . a. since they can make one transparent body of many , why do they not of a great many small sparks of natural diamant compound one great one ? it would bear the charges of all the materials , and beside , enrich them . b. 't is probable it would . but it may be they know no salt that howsoever prepared , which ( with how great a fire soever ) can make them melt . and , it may be the true chrystal of the mountain , which is found in great pieces in the alps , is but a compound of many small ones , and made by the earths annual motion . for it is a very swift motion . suppose now that within a very small cavern of those rocks whose smallest atomes are chrystal , and the cavity fill'd with air ; and consider what a tumult would be made by the swift reciprocation of that air ; whether it would not in time separate those atomes from the rock , and jumbling them together make them rub off their scruf from one another , and by little and little to touch one another in polish'd plains , and consequently stick together , till in length of time they become one lump of clean chrystal . a. i believe that the least parts of created substances lay mingled together at first , till it pleased god to separate all dissimilar natures , and congregate the similar , to which this annual motion is proper . but they say that chrystal is found in the open air hanging like icicles upon the rocks . which ( if true ) defeats this supposition of a narrow cavern . and therefore i must have some further experience of it before i make it my opinion . but howsoever , it still holds true that diaphanous bodies of all sorts , in their least parts , were made by god in the beginning of the world. but it may be true , notwithstanding those icicles . for the force of the air that could break off those diaphanous atomes in a cavern , can do the same in the open air. and i know that a less force of air can break some bodies into small pieces , not much less hard than chystal , by corrupting them . b. that which you now have said is somewhat . but i deny not the possibility , but only doubt of the operation . you may therefore pass to some other question . a. well , i will ask you then a question about refraction . i know already that for the cause of refraction ( when the light falleth through a thinner medium upon a thicker ) you assign the resistance of the thicker body ; but you do not mean there by rarum and densum , two bodies whereof in equal spaces one has more substance in it than the other . b. no. for equal spaces contain equal bodies . but i mean by densum any body which more resisteth the motion of the air , and by rarum that which resisteth less . a. but you have not declared in what that resistance consisteth . b. i suppose it proceedeth from the hardness . a. but from thence it will follow , that all transparent bodies that equally refract are equally hard. which i think is not true , because the refraction of glass is not greater ( at least in comparison of their hardnesses ) than that of water . b. i confess it . therefore i think we must take in gravity to a share in the production of this refraction . for i never considered refraction but in glass ; because my business then was only to find the causes of the phaenomena of telescopes and microscopes . let therefore a b ( in fig. . ) be a hard , and consequently , a heavy body . and from above ( as from the sun ) let c a be the line of incidence , and produced to d. and draw a e perpendicular to a b. it is manifest that the hardness in a b shall turn the stream of the light inwards toward a e , suppose in the line a e. it is also evident that the endeavour in b , which is ( being heavy ) downward , shall turn the stream again inward , towards a e as in a b. thus it is in refraction from the sun downwards . in like manner , if the light come from below , as from a candle in the point d , the line of incidence will be d a , and produced will pass to c. and the resistance of the hardness in a will turn the stream a c inward , suppose into b l , and make c l equal to d e. for passing into a thinner medium , it will depart from the perpendicular in an angle equal to the angle d a e , by which it came nearer to it in a e. so also the resistance of the gravity in the point a shall turn the stream of the light into the line a i , and make the angle l a i equal to the angle e a b. and thus you see in what manner , though not in what proportion hardness and gravity conjoyn their resistance in the causing of refraction . a. but you proved yesterday , that a heavy body does not gravitate upon a body equally heavy . now this a b has upper parts , and lower parts ; and if the upper parts do not gravitate upon the lower parts , how can there be any endeavour at all downward to contribute to the refraction ? b. i told you yesterday , that when a heavy body was set upon another body heavier or harder than it self , the endeavour of it downward was diverted another way , but not that it was extinguished . but in this case , where it lyeth upon air , the first endeavour of the lowest part worketh downward . for neither motion nor body can be utterly extinguished by a less than an omnipotent power . all bodies as long as they are bodies , are in motion one way or other , though the farther it be communicated , so much the less . a. but since you hold that motion is propagated through all bodies , how hard or heavy soever they be , i see no cause but that all bodies should be transparent . b. there are divers causes that take away transparency . first , if the body be not perfectly homogeneous , that is to say , if the smallest parts of it be not all precisely of the same nature , or do not so touch one another as to leave no vacuum within it ; or though they touch , if they be not as hard in the contact as in any other line . for then the refractions will be so changed both in their direction , and in their strength , as that no light shall come through it to the eye ; as in wood and ordinary stone and metal . secondly , the gravity and hardness may be so great , as to make the angle refracted so great , as the second refraction shall not direct the beam of light to the eye ; as if the angle of refraction were d a e , the refracted line would be perpendicular to a b , and never come to the line a d , in which is the eye . a. to know how much of the refraction is due to the hardness , and how much to the gravity , i believe it is impossible , though the quantity of the whole be easily measured in a diaphanous body given . and both you and mr. warner have demonstrated , that as the sine of the angle refracted in one inclination is to the sine of the angle refracted in another inclination , so is the sine of one inclination to the sine of the angle of the other inclination . which demonstrations are both published by mersennus in the end of the first volume of his cogitata physico-mathematica . but since there be many bodies , through which though there pass light enough , yet no object appears through them to the eye , what is the reason of that ? b. you mean paper . for paper-windows will enlighten a room , and yet not show the image of an object without the room . but 't is because there are in paper abundance of pores , through which the air passing moveth the air within ; by the reflections whereof any thing within may be seen . and in the same paper there are again as many parts not transparent , through which the air cannot pass , but must be reflected first to all parts of the object , and from them again to the paper ; and at the paper either reflected again or transmitted , according as it falls upon pores or not pores ; so that the light from the object can never come together at the eye . a. there belongs yet to this subject the causes of the diversity of colours . but i am so well satisfied with that which you have written of it in the th chapter of your book de corpore , that i need not trouble you further in it . and now i have but one question more to ask you , which i thought upon last night . i have read in an antient historian that living creatures after a great deluge were produced by the earth , which being then very soft , there were bred in it ( it may be by the rapid motion of the sun ) many blisters , which in time breaking , brought forth ( like so many eggs ) all manner of living creatures great and small , which since it is grown hard it cannot do . what think you of it ? b. it is true that the earth produced the first living creatures of all sorts but man. for god said , ( gen. . vers . . ) let the earth produce every living creature , cattle , and creeping thing , &c. but then again ( ver . . ) it is said that god made the beast of the earth , &c. so that it is evident that god gave unto the earth that vertue . which vertue must needs consist in motion , because all generation is motion . but man , though the same day , was made afterward . a. why hath not the earth the same vertue now ? is not the sun the same it was ? or is there no earth now soft enough ? b. yes . and it may be the earth may yet produce some very small living creatures : and perhaps male and female . for the smallest creatures which we take notice of , do engender , though they do not all by conjunction ; therefore if the earth produce living creatures at this day , god did not absolutely rest from all his works on the seventh day , but ( as it is cap. . ver . . ) he rested from all the work he had made . and therefore it is no harm to think that god worketh still , and when and where and what he pleaseth . beside , 't is very hard to believe , that to produce male and female , and all that belongs thereto , as also the several and curious organs of sense and memory , could be the work of any thing that had not understanding . from whence , i think we may conclude , that whatsoever was made after the creation , was a new creature made by god no therwise than the first creatures were , excepting only man. a. they are then in an errour that think there are no more different kinds of animals in the world now , than there were in the ark of noah . b. yes doubtless . for they have no text of scripture from which it can be proved . a. the questions of nature which i could yet propound are innumerable . and since i cannot go through them , i must give over somewhere , and why not here ? for i have troubled you enough , though i hope you will forgive me . b. so god forgive us both as we do one another . but forget not to take with you the demonstration of a straight line equal to an arc of a circle . finis . notes, typically marginal, from the original text notes for div a -e fig. . notes for div a -e fig. . fig. .